Reduce sk specific code

The application id can be stored in signkey, then we don't need
to call sk-specific functions from svr-authpubkey

.github/workflows/build.yml

@@ -0,0 +1,151 @@
+# Can be used locally with https://github.com/nektos/act
+
+name: BuildTest
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+jobs:
+  build:
+    runs-on: ${{ matrix.os || 'ubuntu-20.04' }}
+    strategy:
+      matrix:
+        # Rather than a boolean False we use eg
+        #   runcheck: 'no'
+        # Otherwise GH expressions will make a None var
+        # compare with False. We want an undefined default of True.
+
+        # MULTI and NOWRITEV are passed as integers to the build
+        include:
+          - name: plain linux
+
+          - name: multi binary
+            multi: 1
+
+          - name: bundled libtom, bionic , no writev()
+            # test can use an older distro with bundled libtommath
+            os: ubuntu-18.04
+            configure_flags: --enable-bundled-libtom --enable-werror
+            # NOWRITEV is unrelated, test here to save a job
+            nowritev: 1
+            # our tests expect >= python3.7
+            runcheck: 'no'
+
+          - name: linux clang
+            cc: clang
+
+          - name: macos 10.15
+            os: macos-10.15
+            cc: clang
+            # OS X says daemon() and utmp are deprecated
+            extracflags: -Wno-deprecated-declarations
+            runcheck: 'no'
+            apt: 'no'
+            # fails with:
+            # .../ranlib: file: libtomcrypt.a(cbc_setiv.o) has no symbols
+            ranlib: ranlib -no_warning_for_no_symbols
+
+          - name: macos 11
+            os: macos-11
+            cc: clang
+            extracflags: -Wno-deprecated-declarations
+            runcheck: 'no'
+            apt: 'no'
+            ranlib: ranlib -no_warning_for_no_symbols
+
+          # # Fuzzers run standalone. A bit superfluous with cifuzz, but
+          # # good to run the whole corpus to keep it working.
+          # - name: fuzzing with address sanitizer
+          #   configure_flags: --enable-fuzz --disable-harden --enable-bundled-libtom --enable-werror
+          #   ldflags: -fsanitize=address
+          #   extracflags: -fsanitize=address
+          #   fuzz: True
+          #   cc: clang
+
+          # # Undefined Behaviour sanitizer
+          # - name: fuzzing with undefined behaviour sanitizer
+          #   configure_flags: --enable-fuzz --disable-harden --enable-bundled-libtom --enable-werror
+          #   ldflags: -fsanitize=undefined
+          #   # don't fail with alignment due to https://github.com/libtom/libtomcrypt/issues/549
+          #   extracflags: -fsanitize=undefined -fno-sanitize-recover=undefined -fsanitize-recover=alignment
+          #   fuzz: True
+          #   cc: clang
+
+    env:
+      MULTI: ${{ matrix.multi }}
+      CC: ${{ matrix.cc || 'gcc' }}
+      LDFLAGS: ${{ matrix.ldflags }}
+      EXTRACFLAGS: ${{ matrix.extracflags }}
+      CONFIGURE_FLAGS: ${{ matrix.configure_flags || '--enable-werror' }}
+      # for fuzzing
+      CXX: clang++
+      RANLIB: ${{ matrix.ranlib || 'ranlib' }}
+
+    steps:
+      - name: deps
+        if: ${{ matrix.apt != 'no' }}
+        run: |
+          sudo apt-get -y update
+          sudo apt-get -y install zlib1g-dev libtomcrypt-dev libtommath-dev mercurial python3-venv $CC
+
+      - uses: actions/checkout@v2
+
+      - name: configure
+        run: ./configure $CONFIGURE_FLAGS CFLAGS="-O2 -Wall -Wno-pointer-sign $EXTRACFLAGS" --prefix="$HOME/inst" || (cat config.log; exit 1)
+
+      - name: nowritev
+        if: ${{ matrix.nowritev }}
+        run: sed -i -e s/HAVE_WRITEV/DONT_HAVE_WRITEV/ config.h
+
+      - name: make
+        run: make -j3
+
+      - name: multilink
+        if: ${{ matrix.multi }}
+        run: make multilink
+
+      - name: makefuzz
+        run: make fuzzstandalone
+        if: ${{ matrix.fuzz }}
+
+        # avoid concurrent install, osx/freebsd is racey (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=208093)
+      - name: make install
+        run: make install
+
+      - name: keys
+        run: |
+          mkdir -p ~/.ssh
+          ~/inst/bin/dropbearkey -t ecdsa -f ~/.ssh/id_dropbear | grep ^ecdsa > ~/.ssh/authorized_keys
+          chmod 700 ~ ~/.ssh ~/.ssh/authorized_keys
+          ls -ld ~ ~/.ssh ~/.ssh/authorized_keys
+
+        # upload config.log if something has failed
+      - name: config.log
+        if: ${{ !env.ACT && (failure() || cancelled()) }}
+        uses: actions/upload-artifact@v2
+        with:
+          name: config.log
+          path: config.log
+
+      - name: check
+        if: ${{ matrix.runcheck != 'no' }}
+        run: make check
+
+      # Sanity check that the binary runs
+      - name: genrsa
+        run: ~/inst/bin/dropbearkey -t rsa -f testrsa
+      - name: gendss
+        run: ~/inst/bin/dropbearkey -t dss -f testdss
+      - name: genecdsa256
+        run: ~/inst/bin/dropbearkey -t ecdsa -f testec256 -s 256
+      - name: genecdsa384
+        run: ~/inst/bin/dropbearkey -t ecdsa -f testec384 -s 384
+      - name: genecdsa521
+        run: ~/inst/bin/dropbearkey -t ecdsa -f testec521 -s 521
+      - name: gened25519
+        run: ~/inst/bin/dropbearkey -t ed25519 -f tested25519
+
+      - name: fuzz
+        if: ${{ matrix.fuzz }}
+        run: ./fuzzers_test.sh

.github/workflows/cifuzz.yml

@@ -0,0 +1,30 @@
+# Runs fuzzers for a little while on pull requests.
+# From https://google.github.io/oss-fuzz/getting-started/continuous-integration/
+name: CIFuzz
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+jobs:
+  Fuzzing:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Build Fuzzers
+      id: build
+      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'dropbear'
+        dry-run: false
+    - name: Run Fuzzers
+      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
+      with:
+        oss-fuzz-project-name: 'dropbear'
+        fuzz-seconds: 1200
+        dry-run: false
+    - name: Upload Crash
+      uses: actions/upload-artifact@v1
+      if: failure() && steps.build.outcome == 'success'
+      with:
+        name: artifacts
+        path: ./out/artifacts

.gitignore

@@ -5,6 +5,7 @@
 *.bb
 *.bbg
 *.prof
+.*.swp
 /autom4te.cache
 /config.log
 /config.status
@@ -13,10 +14,15 @@
 /dropbearconvert
 /dropbearkey
 /dropbearmulti
+/fuzzcorpus
+/fuzzer-*
+/fuzzer-*.options
 /scp
 /scp-progress
 Makefile
 config.h
-config.h.in
-configure
 default_options_guard.h
+tags
+.pytest*
+*.pyc
+/test/venv

.hgignore

@@ -0,0 +1,6 @@
+\..*\.swp
+.*~
+tags
+.pytest*
+.*\.pyc
+test/venv

.hgsigs

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.hgtags

@@ -55,3 +55,9 @@ cbd674d63cd4f3781464a8d4056a5506c8ae926f DROPBEAR_2015.67
 309e1c4a87682b6ca7d80b8555a1db416c3cb7ac DROPBEAR_2016.73
 0ed3d2bbf956cb8a9bf0f4b5a86b7dd9688205cb DROPBEAR_2016.74
 c31276613181c5cff7854e7ef586ace03424e55e DROPBEAR_2017.75
+1c66ca4f3791c82501c88e7637312182c7294978 DROPBEAR_2018.76
+6d1bbe7d5fa5827c7eae28bca044d691f7efa785 DROPBEAR_2019.77
+009d52ae26d35f3381c801e02318fa9be34be93c DROPBEAR_2019.78
+e2e4929d057b09422f2ea4556fb64209aff58161 DROPBEAR_2020.79
+73646de50f1351735c868d4874f058ff9ad62c96 DROPBEAR_2020.80
+4b984c42372d01fcc2fd487c58af6a5aa65eb88e DROPBEAR_2020.81

.travis.yml

@@ -1,56 +0,0 @@
-language: c
-
-git:
-  depth: 3
-
-matrix:
-  include:
-    # subsequent matrix options use these first settings
-    - os: linux
-      compiler: gcc
-      env: WEXTRAFLAGS=-Werror
-    - env: MULTI=1 WEXTRAFLAGS=-Werror
-    # libtom has some warnings, so no WEXTRAFLAGS
-    - env: BUNDLEDLIBTOM=--enable-bundled-libtom WEXTRAFLAGS=""
-    - env: NOWRITEV=1 WEXTRAFLAGS=-Werror
-    # libtomcrypt 1.18.1 fixes clang problems, distro doesn't have that yet
-    - os: linux
-      compiler: clang
-      env: BUNDLEDLIBTOM=--enable-bundled-libtom WEXTRAFLAGS=""
-    - os: osx
-      compiler: clang
-      env: WEXTRAFLAGS=""
-
-# container-based builds
-sudo: false
-addons:
-  apt:
-    packages:
-    # packages list: https://github.com/travis-ci/apt-package-whitelist/blob/master/ubuntu-precise
-    - zlib1g-dev
-    - libtomcrypt-dev
-    - libtommath-dev
-
-
-before_install:
-  - if [ "$CC" = "clang" ]; then WEXTRAFLAGS="$WEXTRAFLAGS -Wno-error=incompatible-library-redeclaration" ; fi  # workaround
-
-script:
-  - autoconf && autoheader && ./configure "$BUNDLEDLIBTOM" CFLAGS="-O2 -Wall -Wno-pointer-sign $WEXTRAFLAGS" --prefix="$HOME/inst"
-  - if [ "$NOWRITEV" = "1" ]; then sed -i -e s/HAVE_WRITEV/DONT_HAVE_WRITEV/ config.h ; fi
-  - make -j3 
-  # avoid concurrent install, osx/freebsd is racey (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=208093)
-  - make install 
-
-after_success:
-  - ~/inst/bin/dropbearkey -t rsa -f testrsa
-  - ~/inst/bin/dropbearkey -t dss -f testdss
-  - ~/inst/bin/dropbearkey -t ecdsa -f testec256 -s 256
-  - ~/inst/bin/dropbearkey -t ecdsa -f testec384 -s 384
-  - ~/inst/bin/dropbearkey -t ecdsa -f testec521 -s 521
-
-branches:
-  only:
-    - master
-    - coverity
-

CHANGES

@@ -1,13 +1,146 @@
+2020.81 - 29 October 2020
+
+- Fix regression in 2020.79 which prevented connecting with some SSH 
+  implementations. Increase MAX_PROPOSED_ALGO to 50, and print a log 
+  message if the limit is hit. This fixes interoperability with sshj 
+  library (used by PyCharm), and GoAnywhere.
+  Reported by Pirmin Walthert and Piotr Jurkiewicz
+
+- Fix building with non-GCC compilers, reported by Kazuo Kuroi
+
+- Fix potential long delay in dbclient, found by OSS Fuzz
+
+- Fix null pointer dereference crash, found by OSS Fuzz
+
+- libtommath now uses the same random source as Dropbear (in 2020.79 
+  and 2020.80 used getrandom() separately)
+
+- Some fuzzing improvements, start of a dbclient fuzzer
+
+2020.80 - 26 June 2020
+
+- Don't block authorized_keys logins with no-X11-forwarding or no-agent-forwarding 
+  restrictions when X11 or agent forwarding are disabled at compile time.
+  This is more of a problem now X11 is disabled by default, reported by Guilhem Moulin
+
+- Reduce binary size by 4kB (x64) when using bundled libtommath
+
+- Define GNU_SOURCE for getrandom() on uclibc, reported by Laurent Bercot and
+  Fabrice Fontaine
+
+- Improve checking libtomcrypt version compatibility
+
+- Add some style notes to DEVELOPING.md
+
+2020.79 - 15 June 2020
+
+- Support ed25519 hostkeys and authorized_keys, many thanks to Vladislav Grishenko.
+  This also replaces curve25519 with a TweetNaCl implementation that reduces code size.
+
+- Add chacha20-poly1305 authenticated cipher. This will perform faster than AES
+  on many platforms. Thanks to Vladislav Grishenko
+
+- Support using rsa-sha2 signatures. No changes are needed to hostkeys/authorized_keys
+  entries, existing RSA keys can be used with the new signature format (signatures
+  are ephemeral within a session). Old ssh-rsa signatures will no longer
+  be supported by OpenSSH in future so upgrading is recommended.
+
+- Use getrandom() call on Linux to ensure sufficient entropy has been gathered at startup.
+  Dropbear now avoids reading from the random source at startup, instead waiting until
+  the first connection. It is possible that some platforms were running without enough 
+  entropy previously, those could potentially block at first boot generating host keys.
+  The dropbear "-R" option is one way to avoid that.
+
+- Upgrade libtomcrypt to 1.18.2 and libtommath to 1.2.0, many thanks to Steffen Jaeckel for
+  updating Dropbear to use the current API. Dropbear's configure script will check 
+  for sufficient system library versions, otherwise using the bundled versions.
+
+- CBC ciphers, 3DES, hmac-sha1-96, and x11 forwarding are now disabled by default.
+  They can be set in localoptions.h if required.
+  Blowfish has been removed.
+
+- Support AES GCM, patch from Vladislav Grishenko. This is disabled by default,
+  Dropbear doesn't currently use hardware accelerated AES.
+
+- Added an API for specifying user public keys as an authorized_keys replacement.
+  See pubkeyapi.h for details, thanks to Fabrizio Bertocci
+
+- Fix idle detection clashing with keepalives, thanks to jcmathews
+
+- Include IP addresses in more early exit messages making it easier for fail2ban
+  processing. Patch from Kevin Darbyshire-Bryant
+
+- scp fix for CVE-2018-20685 where a server could modify name of output files
+
+- SSH_ORIGINAL_COMMAND is set for "dropbear -c" forced command too
+
+- Fix writing key files on systems without hard links, from Matt Robinson
+
+- Compatibility fixes for IRIX from Kazuo Kuroi
+
+- Re-enable printing MOTD by default, was lost moving from options.h. Thanks to zciendor
+
+- Call fsync() is called on parent directory when writing key files to ensure they are flushed
+
+- Fix "make install" for manpages in out-of-tree builds, from Gabor Z. Papp
+
+- Some notes are added in DEVELOPING.md
+
+2019.78 - 27 March 2019
+
+- Fix dbclient regression in 2019.77. After exiting the terminal would be left
+  in a bad state. Reported by Ryan Woodsmall
+  
+2019.77 - 23 March 2019
+
+- Fix server -R option with ECDSA - only advertise one key size which will be accepted.
+  Reported by Peter Krefting, 2018.76 regression.
+
+- Fix server regression in 2018.76 where multiple client -R forwards were all forwarded 
+  to the first destination. Reported by Iddo Samet.
+
+- Make failure delay more consistent to avoid revealing valid usernames, set server password 
+  limit of 100 characters. Problem reported by usd responsible disclosure team
+
+- Change handling of failed authentication to avoid disclosing valid usernames,
+  CVE-2018-15599. 
+
+- Fix dbclient to reliably return the exit code from the remote server.
+  Reported by W. Mike Petullo
+
+- Fix export of 521-bit ECDSA keys, from Christian Hohnstädt
+
+- Add -o Port=xxx option to work with sshfs, from xcko
+
+- Merged fuzzing code, see FUZZER-NOTES.md
+
+- Add a DROPBEAR_SVR_MULTIUSER=0 compile option to run on 
+  single-user Linux kernels (CONFIG_MULTIUSER disabled). From Patrick Stewart
+
+- Increase allowed username to 100 characters, reported by W. Mike Petullo
+
+- Update config.sub and config.guess, should now work with RISC-V
+
+- Cygwin compile fix from karel-m
+
+- Don't require GNU sed (accidentally in 2018.76), reported by Samuel Hsu
+
+- Fix for IRIX and writev(), reported by Kazuo Kuroi
+
+- Other fixes and cleanups from François Perrad, Andre McCurdy, Konstantin Demin,
+  Michael Jones, Pawel Rapkiewicz
+
+
 2018.76 - 27 February 2018
 
 > > > Configuration/compatibility changes
   IMPORTANT
-  Custom configuration is now specified in local_options.h rather than options.h
+  Custom configuration is now specified in localoptions.h rather than options.h
   Available options and defaults can be seen in default_options.h
 
   To migrate your configuration, compare your customised options.h against the
   upstream options.h from your relevant version. Any customised options should
-  be put in localoptions.h
+  be put in localoptions.h in the build directory.
 
 - "configure --enable-static" should now be used instead of "make STATIC=1"
   This will avoid 'hardened build' flags that conflict with static binaries
@@ -101,7 +234,7 @@
   dropbear is running with -a (Allow connections to forwarded ports from any host)
   This could potentially allow arbitrary code execution as root by an authenticated user.
   Affects versions 2013.56 to 2016.74. Thanks to Mark Shepard for reporting the crash.
-  CVE-2017-9078 https://secure.ucc.asn.au/hg/dropbear/rev/c8114a48837c
+  CVE-2017-9078 https://hg.ucc.asn.au/dropbear/rev/c8114a48837c
 
 - Security: Fix information disclosure with ~/.ssh/authorized_keys symlink.
   Dropbear parsed authorized_keys as root, even if it were a symlink. The fix
@@ -113,7 +246,7 @@
   contents of that file.
   This information disclosure is to an already authenticated user.
   Thanks to Jann Horn of Google Project Zero for reporting this.
-  CVE-2017-9079 https://secure.ucc.asn.au/hg/dropbear/rev/0d889b068123
+  CVE-2017-9079 https://hg.ucc.asn.au/dropbear/rev/0d889b068123
 
 - Generate hostkeys with dropbearkey atomically and flush to disk with fsync
   Thanks to Andrei Gherzan for a patch
@@ -133,23 +266,23 @@
   run arbitrary code as the dbclient user. This could be a problem if scripts
   or webpages pass untrusted input to the dbclient program.
   CVE-2016-7406
-  https://secure.ucc.asn.au/hg/dropbear/rev/b66a483f3dcb
+  https://hg.ucc.asn.au/dropbear/rev/b66a483f3dcb
 
 - Security: dropbearconvert import of OpenSSH keys could run arbitrary code as
   the local dropbearconvert user when parsing malicious key files
   CVE-2016-7407
-  https://secure.ucc.asn.au/hg/dropbear/rev/34e6127ef02e
+  https://hg.ucc.asn.au/dropbear/rev/34e6127ef02e
 
 - Security: dbclient could run arbitrary code as the local dbclient user if
   particular -m or -c arguments are provided. This could be an issue where
   dbclient is used in scripts.
   CVE-2016-7408
-  https://secure.ucc.asn.au/hg/dropbear/rev/eed9376a4ad6
+  https://hg.ucc.asn.au/dropbear/rev/eed9376a4ad6
 
 - Security: dbclient or dropbear server could expose process memory to the
   running user if compiled with DEBUG_TRACE and running with -v
   CVE-2016-7409
-  https://secure.ucc.asn.au/hg/dropbear/rev/6a14b1f6dc04
+  https://hg.ucc.asn.au/dropbear/rev/6a14b1f6dc04
 
   The security issues were reported by an anonymous researcher working with
   Beyond Security's SecuriTeam Secure Disclosure www.beyondsecurity.com/ssd.html
@@ -195,7 +328,7 @@
 
 - Validate X11 forwarding input. Could allow bypass of authorized_keys command= restrictions,
   found by github.com/tintinweb. Thanks for Damien Miller for a patch. CVE-2016-3116
-  https://secure.ucc.asn.au/hg/dropbear/rev/a3e8389e01ff
+  https://hg.ucc.asn.au/dropbear/rev/a3e8389e01ff
 
 2015.71 - 3 December 2015
 
@@ -476,11 +609,11 @@ kernels, from Steve Dover
 - Limit the size of decompressed payloads, avoids memory exhaustion denial
   of service 
   Thanks to Logan Lamb for reporting and investigating it. CVE-2013-4421
-  https://secure.ucc.asn.au/hg/dropbear/rev/0bf76f54de6f
+  https://hg.ucc.asn.au/dropbear/rev/0bf76f54de6f
 
 - Avoid disclosing existence of valid users through inconsistent delays
   Thanks to Logan Lamb for reporting. CVE-2013-4434
-  https://secure.ucc.asn.au/hg/dropbear/rev/d7784616409a
+  https://hg.ucc.asn.au/dropbear/rev/d7784616409a
 
 - Update config.guess and config.sub for newer architectures
 
@@ -583,7 +716,7 @@ though probably will be soon
   This bug affects releases 0.52 onwards. Ref CVE-2012-0920.
   Thanks to Danny Fullerton of Mantor Organization for reporting
   the bug.
-  https://secure.ucc.asn.au/hg/dropbear/rev/818108bf7749
+  https://hg.ucc.asn.au/dropbear/rev/818108bf7749
 
 - Compile fix, only apply IPV6 socket options if they are available in headers
   Thanks to Gustavo Zacarias for the patch
@@ -627,7 +760,7 @@ though probably will be soon
 - New version numbering scheme.
 
 Source repository has now migrated to Mercurial at 
-https://secure.ucc.asn.au/hg/dropbear/graph/default
+https://hg.ucc.asn.au/dropbear/graph/default
 
 0.53.1 - Wednesday 2 March 2011
 

DEVELOPING.md

@@ -0,0 +1,75 @@
+# Developer Notes
+
+## Building
+
+See [INSTALL](INSTALL) for build instructions. 
+[SMALL](SMALL) has hints for building smaller binaries, also see comments
+in default_options.h.
+
+## Debug printing
+
+Set `#define DEBUG_TRACE 1` in localoptions.h to enable a `-v` option
+for dropbear and dbclient. That prints various details of the session. For
+development running `dropbear -F -E` is useful to run in the foreground. You
+can set `#define DEBUG_NOFORK 1` to make dropbear a one-shot server, easy to 
+run under a debugger.
+
+## Random sources
+
+Most cryptography requires a good random entropy source, both to generate secret
+keys and in the course of a session. Dropbear uses the Linux kernel's
+`getrandom()` syscall to ensure that the system RNG has been initialised before
+using it. On some systems there is insufficient entropy gathered during early
+boot - generating hostkeys then will block for some amount of time. 
+Dropbear has a `-R` option to generate hostkeys upon the first connection 
+as required - that will allow the system more time to gather entropy.
+
+## Algorithms
+
+Default algorithm lists are specified in [common-algo.c](common-algo.c).
+They are in priority order, the client's first matching choice is used
+(see rfc4253). 
+Dropbear client has `-c` and `-m` arguments to choose which are enabled at
+runtime (doesn't work for server as of June 2020).
+
+Enabling/disabling algorithms is done in [localoptions.h](localoptions.h),
+see [default_options.h](default_options.h).
+
+## Style
+
+Source code is indented with tabs, width set to 4 (though width shouldn't
+matter much). Braces are on the same line as functions/loops/if - try
+to keep consistency with existing code.
+
+All `if` statements should have braces, no exceptions.
+
+Avoid using pointer arithmetic, instead the functions in
+[buffer.h](buffer.h) should be used.
+
+Some Dropbear platforms have old compilers.
+Variable declarations must be at the top of a scope and
+comments must be `/* */` rather than `//`.
+
+Pointer variables should be initialised to NULL - it can reduce the
+severity of bugs.
+
+## Third party code
+
+Libtomcrypt and libtommath are periodically synced from upstream, so
+avoid making changes to that code which will need to be maintained.
+Improvements can be sent upstream to the libtom project.
+
+## Non-root user
+
+Dropbear server will run fine as a non-root user, allowing logins only for 
+that user. Password authentication probably won't work (can't read shadow 
+passwords). You will need to create hostkeys that are readable.
+
+## Connection setup 
+
+Dropbear implements first_kex_packet_follows to reduce 
+handshake latency (rfc 4253 7.1). Some less common implementations don't 
+handle that, it can be a cause of problems connecting. Note also that
+Dropbear may send several ssh packets within a single TCP packet - it's just a 
+stream.
+

FUZZER-NOTES.md

@@ -0,0 +1,77 @@
+# Fuzzing Dropbear
+
+Dropbear is process-per-session so it assumes calling `dropbear_exit()`
+is fine at any point to clean up. This makes fuzzing a bit trickier. 
+A few pieces of wrapping infrastructure are used to work around this.
+
+The [libfuzzer](http://llvm.org/docs/LibFuzzer.html#fuzz-target) harness
+expects a long running process to continually run a test function with 
+a string of crafted input. That process should not leak resources or exit.
+
+## longjmp
+
+When dropbear runs in fuzz mode it sets up a 
+[`setjmp()`](http://man7.org/linux/man-pages/man3/setjmp.3.html) target prior 
+to launching the code to be fuzzed, and then [`dropbear_exit()`](dbutil.c#L125)
+calls `longjmp()` back there. This avoids exiting though it doesn't free 
+memory or other resources.
+
+## malloc Wrapper
+
+Dropbear normally uses a [`m_malloc()`](dbmalloc.c) function that is the same as `malloc()` but
+exits if allocation fails. In fuzzing mode this is replaced with a tracking allocator
+that stores all allocations in a linked list. After the `longjmp()` occurs the fuzzer target
+calls [`m_malloc_free_epoch(1, 1)`](dbmalloc.c) to clean up any unreleased memory.
+
+If the fuzz target runs to completion it calls `m_malloc_free_epoch(1, 0)` which will reset 
+the tracked allocations but will not free memory - that allows libfuzzer's leak checking
+to detect leaks in normal operation.
+
+## File Descriptor Input
+
+As a network process Dropbear reads and writes from a socket. The wrappers for
+`read()`/`write()`/`select()` in [fuzz-wrapfd.c](fuzz-wrapfd.c) will read from the
+fuzzer input that has been set up with `wrapfd_add()`. `write()` output is
+currently discarded.
+These also test error paths such as EINTR and short reads with certain probabilities.
+
+This allows running the entire dropbear server process with network input provided by the
+fuzzer, without many modifications to the main code. At the time of writing this 
+only runs the pre-authentication stages, though post-authentication could be run similarly.
+
+## Encryption and Randomness
+
+When running in fuzzing mode Dropbear uses a [fixed seed](dbrandom.c#L185)
+every time so that failures can be reproduced. 
+
+Since the fuzzer cannot generate valid encrypted input the packet decryption and
+message authentication calls are disabled, see [packet.c](packet.c). 
+MAC failures are set to occur with a low probability to test that error path.
+
+## Fuzzers
+
+Current fuzzers are
+
+- [fuzzer-preauth](fuzzer-preauth.c) - the fuzzer input is treated as a stream of session input. This will
+  test key exchange, packet ordering, authentication attempts etc.
+
+- [fuzzer-preauth_nomaths](fuzzer-preauth_nomaths.c) - the same as fuzzer-preauth but with asymmetric crypto
+  routines replaced with dummies for faster runtime. corpora are shared 
+  between fuzzers by [oss-fuzz](https://github.com/google/oss-fuzz) so this 
+  will help fuzzer-preauth too.
+
+- [fuzzer-verify](fuzzer-verify.c) - read a key and signature from fuzzer input and verify that signature. 
+  It would not be expected to pass, though some keys with bad parameters are 
+  able to validate with a trivial signature - extra checks are added for that.
+
+- [fuzzer-pubkey](fuzzer-pubkey.c) - test parsing of an `authorized_keys` line.
+
+- [fuzzer-kexdh](fuzzer-kexdh.c) - test Diffie-Hellman key exchange where the fuzz input is the 
+  ephemeral public key that would be received over the network. This is testing `mp_expt_mod()`
+  and and other libtommath routines.
+
+- [fuzzer-kexecdh](fuzzer-kexecdh.c) - test Elliptic Curve Diffie-Hellman key exchange like fuzzer-kexdh.
+  This is testing libtommath ECC routines.
+
+- [fuzzer-kexcurve25519](fuzzer-kexcurve25519.c) - test Curve25519 Elliptic Curve Diffie-Hellman key exchange
+  like fuzzer-kexecdh. This is testing `dropbear_curve25519_scalarmult()` and other libtommath routines.

INSTALL

@@ -3,13 +3,15 @@ Basic Dropbear build instructions:
 - Edit localoptions.h to set which features you want. Available options
   are described in default_options.h, these will be overridden by
   anything set in localoptions.h
-
-- If using a Mercurial or Git checkout, "autoconf; autoheader"
+  localoptions.h should be located in the build directory if you are
+  building out of tree.
 
 - Configure for your system:
   ./configure     (optionally with --disable-zlib or --disable-syslog,
                   or --help for other options)
 
+  (you'll need to first run "autoconf; autoheader" if you edit configure.ac)
+
 - Compile:
 
   make PROGRAMS="dropbear dbclient dropbearkey dropbearconvert scp"
@@ -26,6 +28,8 @@ Basic Dropbear build instructions:
 recompile after changing the PROGRAMS list, you *MUST* "make clean" before
 recompiling - bad things will happen otherwise)
 
+DEVELOPING.md has some notes on other developer topics, including debugging.
+
 See MULTI for instructions on making all-in-one binaries.
 
 If you want to compile statically use ./configure --enable-static
@@ -54,7 +58,7 @@ Compiling for uClibc should be the same as normal, just set CC to the magic
 uClibc toolchain compiler (ie export CC=i386-uclibc-gcc or whatever).
 You can use "make STATIC=1" to make statically linked binaries, and it is
 advisable to strip the binaries too. If you're looking to make a small binary,
-you should remove unneeded ciphers and MD5, by editing options.h
+you should remove unneeded ciphers and MD5, by editing localoptions.h
 
 It is possible to compile zlib in, by copying zlib.h and zconf.h into a
 subdirectory (ie zlibincludes), and 

LICENSE

@@ -8,7 +8,7 @@ The majority of code is written by Matt Johnston, under the license below.
 Portions of the client-mode work are (c) 2004 Mihnea Stoenescu, under the
 same license:
 
-Copyright (c) 2002-2015 Matt Johnston
+Copyright (c) 2002-2020 Matt Johnston
 Portions copyright (c) 2004 Mihnea Stoenescu
 All rights reserved.
 
@@ -32,7 +32,8 @@ SOFTWARE.
 
 =====
 
-LibTomCrypt and LibTomMath are written by Tom St Denis, and are Public Domain.
+LibTomCrypt and LibTomMath are written by Tom St Denis and others, see
+libtomcrypt/LICENSE and libtommath/LICENSE.
 
 =====
 
@@ -90,52 +91,24 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 =====
 
-curve25519-donna:
+curve25519.c:
 
-/* Copyright 2008, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * curve25519-donna: Curve25519 elliptic curve, public key function
- *
- * http://code.google.com/p/curve25519-donna/
- *
- * Adam Langley <agl@imperialviolet.org>
- *
- * Derived from public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
- *
- * More information about curve25519 can be found here
- *   http://cr.yp.to/ecdh.html
- *
- * djb's sample implementation of curve25519 is written in a special assembly
- * language called qhasm and uses the floating point registers.
- *
- * This is, almost, a clean room reimplementation from the curve25519 paper. It
- * uses many of the tricks described therein. Only the crecip function is taken
- * from the sample implementation.
- */
+Modified TweetNaCl version 20140427, a self-contained public-domain C library.
+https://tweetnacl.cr.yp.to/
+
+Contributors (alphabetical order)
+Daniel J. Bernstein, University of Illinois at Chicago and Technische
+Universiteit Eindhoven
+Bernard van Gastel, Radboud Universiteit Nijmegen
+Wesley Janssen, Radboud Universiteit Nijmegen
+Tanja Lange, Technische Universiteit Eindhoven
+Peter Schwabe, Radboud Universiteit Nijmegen
+Sjaak Smetsers, Radboud Universiteit Nijmegen
+
+Acknowledgments
+This work was supported by the U.S. National Science Foundation under grant
+1018836. "Any opinions, findings, and conclusions or recommendations expressed
+in this material are those of the author(s) and do not necessarily reflect the
+views of the National Science Foundation."
+This work was supported by the Netherlands Organisation for Scientific
+Research (NWO) under grant 639.073.005 and Veni 2013 project 13114.

Makefile.in

@@ -35,8 +35,10 @@ COMMONOBJS=dbutil.o buffer.o dbhelpers.o \
 		signkey.o rsa.o dbrandom.o \
 		queue.o \
 		atomicio.o compat.o fake-rfc2553.o \
-		ltc_prng.o ecc.o ecdsa.o crypto_desc.o \
-		gensignkey.o gendss.o genrsa.o
+		ltc_prng.o ecc.o ecdsa.o sk-ecdsa.o crypto_desc.o \
+		curve25519.o ed25519.o sk-ed25519.o \
+		dbmalloc.o \
+		gensignkey.o gendss.o genrsa.o gened25519.o
 
 SVROBJS=svr-kex.o svr-auth.o sshpty.o \
 		svr-authpasswd.o svr-authpubkey.o svr-authpubkeyoptions.o svr-session.o svr-service.o \
@@ -51,7 +53,7 @@ CLIOBJS=cli-main.o cli-auth.o cli-authpasswd.o cli-kex.o \
 CLISVROBJS=common-session.o packet.o common-algo.o common-kex.o \
 			common-channel.o common-chansession.o termcodes.o loginrec.o \
 			tcp-accept.o listener.o process-packet.o dh_groups.o \
-			common-runopts.o circbuffer.o curve25519-donna.o list.o netio.o
+			common-runopts.o circbuffer.o list.o netio.o chachapoly.o gcm.o
 
 KEYOBJS=dropbearkey.o
 
@@ -59,11 +61,34 @@ CONVERTOBJS=dropbearconvert.o keyimport.o
 
 SCPOBJS=scp.o progressmeter.o atomicio.o scpmisc.o compat.o
 
-dropbearobjs=$(COMMONOBJS) $(CLISVROBJS) $(SVROBJS)
-dbclientobjs=$(COMMONOBJS) $(CLISVROBJS) $(CLIOBJS)
-dropbearkeyobjs=$(COMMONOBJS) $(KEYOBJS)
-dropbearconvertobjs=$(COMMONOBJS) $(CONVERTOBJS)
-scpobjs=$(SCPOBJS)
+ifeq (@DROPBEAR_FUZZ@, 1)
+	allobjs = $(COMMONOBJS) fuzz/fuzz-common.o  fuzz/fuzz-wrapfd.o $(CLISVROBJS) $(CLIOBJS) $(SVROBJS) @CRYPTLIB@
+	allobjs:=$(subst svr-main.o, ,$(allobjs))
+	allobjs:=$(subst cli-main.o, ,$(allobjs))
+
+	dropbearobjs=$(allobjs) svr-main.o
+	dbclientobjs=$(allobjs) cli-main.o
+	dropbearkeyobjs=$(allobjs) $(KEYOBJS)
+	dropbearconvertobjs=$(allobjs) $(CONVERTOBJS)
+	# CXX only set when fuzzing
+	CXX=@CXX@
+	FUZZ_CLEAN=fuzz-clean
+else
+	dropbearobjs=$(COMMONOBJS) $(CLISVROBJS) $(SVROBJS)
+	dbclientobjs=$(COMMONOBJS) $(CLISVROBJS) $(CLIOBJS)
+	dropbearkeyobjs=$(COMMONOBJS) $(KEYOBJS)
+	dropbearconvertobjs=$(COMMONOBJS) $(CONVERTOBJS)
+	scpobjs=$(SCPOBJS)
+endif
+
+ifeq (@DROPBEAR_PLUGIN@, 1)
+    # rdynamic makes all the global symbols of dropbear available to all the loaded shared libraries
+    # this allow a plugin to reuse existing crypto/utilities like base64_decode/base64_encode without
+    # the need to rewrite them.
+    PLUGIN_LIBS=-ldl -rdynamic
+else
+    PLUGIN_LIBS=
+endif
 
 VPATH=@srcdir@
 srcdir=@srcdir@
@@ -150,7 +175,7 @@ insmulti%: dropbearmulti$(EXEEXT)
 	-rm -f $(DESTDIR)$(bindir)/$*$(EXEEXT) 
 	-ln -s $(bindir)/dropbearmulti$(EXEEXT) $(DESTDIR)$(bindir)/$*$(EXEEXT) 
 	$(INSTALL) -d $(DESTDIR)$(mandir)/man1
-	if test -e $*.1; then $(INSTALL) -m 644 $*.1 $(DESTDIR)$(mandir)/man1/$*.1; fi
+	if test -e $(srcdir)/$*.1; then $(INSTALL) -m 644 $(srcdir)/$*.1 $(DESTDIR)$(mandir)/man1/$*.1; fi
 
 # dropbear should go in sbin, so it needs a separate rule
 inst_dropbear: dropbear
@@ -163,7 +188,7 @@ inst_%: %
 	$(INSTALL) -d $(DESTDIR)$(bindir)
 	$(INSTALL) $*$(EXEEXT) $(DESTDIR)$(bindir)
 	$(INSTALL) -d $(DESTDIR)$(mandir)/man1
-	if test -e $*.1; then $(INSTALL) -m 644 $*.1 $(DESTDIR)$(mandir)/man1/$*.1; fi
+	if test -e $(srcdir)/$*.1; then $(INSTALL) -m 644 $(srcdir)/$*.1 $(DESTDIR)$(mandir)/man1/$*.1; fi
 
 inst_dropbearmulti: $(addprefix insmulti, $(PROGRAMS)) 
 
@@ -174,13 +199,13 @@ dropbearkey: $(dropbearkeyobjs)
 dropbearconvert: $(dropbearconvertobjs)
 
 dropbear: $(HEADERS) $(LIBTOM_DEPS) Makefile
-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@
+	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS) @CRYPTLIB@ $(PLUGIN_LIBS)
 
 dbclient: $(HEADERS) $(LIBTOM_DEPS) Makefile
 	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS)
 
 dropbearkey dropbearconvert: $(HEADERS) $(LIBTOM_DEPS) Makefile
-	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS)
+	$(CC) $(LDFLAGS) -o $@$(EXEEXT) $($@objs) $(LIBTOM_LIBS) $(LIBS)
 
 # scp doesn't use the libs so is special.
 scp: $(SCPOBJS)  $(HEADERS) Makefile
@@ -211,7 +236,7 @@ $(STATIC_LTC): $(OPTION_HEADERS)
 $(STATIC_LTM): $(OPTION_HEADERS)
 	$(MAKE) -C libtommath
 
-.PHONY : clean sizes thisclean distclean tidy ltc-clean ltm-clean
+.PHONY : clean sizes thisclean distclean tidy ltc-clean ltm-clean lint check
 
 ltc-clean:
 	$(MAKE) -C libtomcrypt clean
@@ -222,7 +247,7 @@ ltm-clean:
 sizes: dropbear
 	objdump -t dropbear|grep ".text"|cut -d "." -f 2|sort -rn
 
-clean: $(LIBTOM_CLEAN) thisclean
+clean: $(LIBTOM_CLEAN) $(FUZZ_CLEAN) thisclean
 
 thisclean:
 	-rm -f dropbear$(EXEEXT) dbclient$(EXEEXT) dropbearkey$(EXEEXT) \
@@ -236,3 +261,67 @@ distclean: clean tidy
 
 tidy:
 	-rm -f *~ *.gcov */*~
+
+lint:
+	cd $(srcdir); ./dropbear_lint.sh
+
+check: lint
+	make -C test
+
+## Fuzzing targets
+
+# list of fuzz targets
+FUZZ_TARGETS=fuzzer-preauth fuzzer-pubkey fuzzer-verify fuzzer-preauth_nomaths \
+	fuzzer-kexdh fuzzer-kexecdh fuzzer-kexcurve25519 fuzzer-client fuzzer-client_nomaths \
+	fuzzer-postauth_nomaths
+
+FUZZER_OPTIONS = $(addsuffix .options, $(FUZZ_TARGETS))
+FUZZ_OBJS = $(addprefix fuzz/,$(addsuffix .o,$(FUZZ_TARGETS))) \
+	fuzz/fuzz-sshpacketmutator.o
+
+list-fuzz-targets:
+	@echo $(FUZZ_TARGETS)
+
+# fuzzers that don't use libfuzzer, just a standalone harness that feeds inputs
+fuzzstandalone: FUZZLIB=fuzz/fuzz-harness.o
+fuzzstandalone: fuzz/fuzz-harness.o fuzz-targets
+
+# Build all the fuzzers. Usually like
+#   make fuzz-targets FUZZLIB=-lFuzzer.a 
+# the library provides main(). Otherwise
+#   make fuzzstandalone
+# provides a main in fuzz-harness.c
+fuzz-targets: $(FUZZ_TARGETS) $(FUZZER_OPTIONS)
+
+$(FUZZ_TARGETS): $(FUZZ_OBJS) $(allobjs) $(LIBTOM_DEPS) 
+	$(CXX) $(CXXFLAGS) fuzz/$@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
+
+# fuzzers that use the custom mutator - these expect a SSH network stream
+MUTATOR_FUZZERS=fuzzer-client fuzzer-client_nomaths \
+	fuzzer-preauth fuzzer-preauth_nomaths fuzzer-postauth_nomaths
+
+# Skip custom mutators for -fsanitize-memory since libfuzzer doesn't initialise memory
+# Pending fix for it https://github.com/google/oss-fuzz/issues/4605
+ifeq (,$(findstring fsanitize=memory, $(CFLAGS)))
+$(MUTATOR_FUZZERS): allobjs += fuzz/fuzz-sshpacketmutator.o
+endif
+
+fuzzer-%.options: Makefile
+	echo "[libfuzzer]"               > $@
+	echo "max_len = 50000"          >> $@
+
+# run this to update hardcoded hostkeys for for fuzzing. 
+# hostkeys.c is checked in to hg.
+fuzz-hostkeys:
+	dropbearkey -t rsa -f keyr
+	dropbearkey -t dss -f keyd
+	dropbearkey -t ecdsa -size 256 -f keye
+	dropbearkey -t ed25519 -f keyed25519
+	echo > hostkeys.c
+	/usr/bin/xxd -i -a keyr >> hostkeys.c
+	/usr/bin/xxd -i -a keye >> hostkeys.c
+	/usr/bin/xxd -i -a keyd >> hostkeys.c
+	/usr/bin/xxd -i -a keyed25519 >> hostkeys.c
+
+fuzz-clean:
+	-rm -f fuzz/*.o $(FUZZ_TARGETS) $(FUZZER_OPTIONS)

README

@@ -51,10 +51,11 @@ dropbearkey's '-y' option.
 
 ============================================================================
 
-To run the server, you need to server keys, this is one-off:
+To run the server, you need to generate server keys, this is one-off:
 ./dropbearkey -t rsa -f dropbear_rsa_host_key
 ./dropbearkey -t dss -f dropbear_dss_host_key
 ./dropbearkey -t ecdsa -f dropbear_ecdsa_host_key
+./dropbearkey -t ed25519 -f dropbear_ed25519_host_key
 
 or alternatively convert OpenSSH keys to Dropbear:
 ./dropbearconvert openssh dropbear /etc/ssh/ssh_host_dsa_key dropbear_dss_host_key

agentfwd.h

@@ -32,6 +32,9 @@
 
 #if DROPBEAR_CLI_AGENTFWD
 
+/* From OpenSSH authfd.h */
+#define SSH_AGENT_RSA_SHA2_256          0x02
+
 /* An agent reply can be reasonably large, as it can
  * contain a list of all public keys held by the agent.
  * 10000 is arbitrary */
@@ -40,7 +43,7 @@
 /* client functions */
 void cli_load_agent_keys(m_list * ret_list);
 void agent_buf_sign(buffer *sigblob, sign_key *key, 
-	const buffer *data_buf);
+		const buffer *data_buf, enum signature_type type);
 void cli_setup_agent(const struct Channel *channel);
 
 #ifdef __hpux

algo.h

@@ -47,7 +47,7 @@ typedef struct Algo_Type algo_type;
 
 /* lists mapping ssh types of algorithms to internal values */
 extern algo_type sshkex[];
-extern algo_type sshhostkey[];
+extern algo_type sigalgs[];
 extern algo_type sshciphers[];
 extern algo_type sshhashes[];
 extern algo_type ssh_compress[];
@@ -72,6 +72,14 @@ struct dropbear_cipher_mode {
 			unsigned long len, void *cipher_state);
 	int (*decrypt)(const unsigned char *ct, unsigned char *pt, 
 			unsigned long len, void *cipher_state);
+	int (*aead_crypt)(unsigned int seq,
+			const unsigned char *in, unsigned char *out,
+			unsigned long len, unsigned long taglen,
+			void *cipher_state, int direction);
+	int (*aead_getlength)(unsigned int seq,
+			const unsigned char *in, unsigned int *outlen,
+			unsigned long len, void *cipher_state);
+	const struct dropbear_hash *aead_mac;
 };
 
 struct dropbear_hash {
@@ -112,21 +120,17 @@ struct dropbear_kex {
 	const struct ltc_hash_descriptor *hash_desc;
 };
 
-int have_algo(const char* algo, size_t algolen, const algo_type algos[]);
+/* Includes all algorithms is useall is set */
+void buf_put_algolist_all(buffer * buf, const algo_type localalgos[], int useall);
+/* Includes "usable" algorithms */
 void buf_put_algolist(buffer * buf, const algo_type localalgos[]);
 
-enum kexguess2_used {
-	KEXGUESS2_LOOK,
-	KEXGUESS2_NO,
-	KEXGUESS2_YES,
-};
-
 #define KEXGUESS2_ALGO_NAME "kexguess2@matt.ucc.asn.au"
-#define KEXGUESS2_ALGO_ID 99
-
 
+int buf_has_algo(buffer *buf, const char *algo);
+algo_type * first_usable_algo(algo_type algos[]);
 algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],
-		enum kexguess2_used *kexguess2, int *goodguess);
+		int kexguess2, int *goodguess);
 
 #if DROPBEAR_USER_ALGO_LIST
 int check_user_algos(const char* user_algo_list, algo_type * algos, 

auth.h

@@ -30,16 +30,15 @@
 #include "chansession.h"
 
 void svr_authinitialise(void);
-void cli_authinitialise(void);
 
 /* Server functions */
 void recv_msg_userauth_request(void);
 void send_msg_userauth_failure(int partial, int incrfail);
 void send_msg_userauth_success(void);
 void send_msg_userauth_banner(const buffer *msg);
-void svr_auth_password(void);
-void svr_auth_pubkey(void);
-void svr_auth_pam(void);
+void svr_auth_password(int valid_user);
+void svr_auth_pubkey(int valid_user);
+void svr_auth_pam(int valid_user);
 
 #if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
 int svr_pubkey_allows_agentfwd(void);
@@ -78,7 +77,7 @@ char* getpass_or_cancel(const char* prompt);
 void cli_auth_pubkey_cleanup(void);
 
 
-#define MAX_USERNAME_LEN 25 /* arbitrary for the moment */
+#define MAX_USERNAME_LEN 100 /* arbitrary for the moment */
 
 #define AUTH_TYPE_NONE      1
 #define AUTH_TYPE_PUBKEY    (1 << 1)
@@ -108,11 +107,14 @@ struct AuthState {
 	unsigned int authdone; /* 0 if we haven't authed, 1 if we have. Applies for
 							  client and server (though has differing 
 							  meanings). */
+
 	unsigned int perm_warn; /* Server only, set if bad permissions on 
 							   ~/.ssh/authorized_keys have already been
 							   logged. */
 	unsigned int checkusername_failed;  /* Server only, set if checkusername
 	                                has already failed */
+	struct timespec auth_starttime; /* Server only, time of receiving current 
+									SSH_MSG_USERAUTH_REQUEST */
 
 	/* These are only used for the server */
 	uid_t pw_uid;

bignum.c

@@ -86,7 +86,7 @@ void m_mp_free_multi(mp_int **mp, ...)
 
 void bytes_to_mp(mp_int *mp, const unsigned char* bytes, unsigned int len) {
 
-	if (mp_read_unsigned_bin(mp, (unsigned char*)bytes, len) != MP_OKAY) {
+	if (mp_from_ubin(mp, (unsigned char*)bytes, len) != MP_OKAY) {
 		dropbear_exit("Mem alloc error");
 	}
 }

buffer.c

@@ -39,44 +39,30 @@
 
 /* Create (malloc) a new buffer of size */
 buffer* buf_new(unsigned int size) {
-
 	buffer* buf;
-	
 	if (size > BUF_MAX_SIZE) {
 		dropbear_exit("buf->size too big");
 	}
 
 	buf = (buffer*)m_malloc(sizeof(buffer)+size);
-
-	if (size > 0) {
-		buf->data = (unsigned char*)buf + sizeof(buffer);
-	} else {
-		buf->data = NULL;
-	}
-
+	buf->data = (unsigned char*)buf + sizeof(buffer);
 	buf->size = size;
-
 	return buf;
-
 }
 
 /* free the buffer's data and the buffer itself */
 void buf_free(buffer* buf) {
-
 	m_free(buf);
 }
 
 /* overwrite the contents of the buffer to clear it */
 void buf_burn(const buffer* buf) {
-	
 	m_burn(buf->data, buf->size);
-
 }
 
 /* resize a buffer, pos and len will be repositioned if required when
  * downsizing */
 buffer* buf_resize(buffer *buf, unsigned int newsize) {
-
 	if (newsize > BUF_MAX_SIZE) {
 		dropbear_exit("buf->size too big");
 	}
@@ -139,18 +125,23 @@ void buf_incrwritepos(buffer* buf, unsigned int incr) {
 	}
 }
 
-/* increment the position by incr, negative values are allowed, to
- * decrement the pos*/
-void buf_incrpos(buffer* buf,  int incr) {
+/* increment the position by incr */
+void buf_incrpos(buffer* buf, unsigned int incr) {
 	if (incr > BUF_MAX_INCR 
-		|| incr < -BUF_MAX_INCR 
-		|| (unsigned int)((int)buf->pos + incr) > buf->len
-		|| ((int)buf->pos + incr) < 0) {
+		|| (buf->pos + incr) > buf->len) {
 		dropbear_exit("Bad buf_incrpos");
 	}
 	buf->pos += incr;
 }
 
+/* decrement the position by decr */
+void buf_decrpos(buffer* buf, unsigned int decr) {
+	if (decr > buf->pos) {
+		dropbear_exit("Bad buf_decrpos");
+	}
+	buf->pos -= decr;
+}
+
 /* Get a byte from the buffer and increment the pos */
 unsigned char buf_getbyte(buffer* buf) {
 
@@ -209,6 +200,7 @@ char* buf_getstring(buffer* buf, unsigned int *retlen) {
 
 	unsigned int len;
 	char* ret;
+	void* src = NULL;
 	len = buf_getint(buf);
 	if (len > MAX_STRING_LEN) {
 		dropbear_exit("String too long");
@@ -217,8 +209,9 @@ char* buf_getstring(buffer* buf, unsigned int *retlen) {
 	if (retlen != NULL) {
 		*retlen = len;
 	}
+	src = buf_getptr(buf, len);
 	ret = m_malloc(len+1);
-	memcpy(ret, buf_getptr(buf, len), len);
+	memcpy(ret, src, len);
 	buf_incrpos(buf, len);
 	ret[len] = '\0';
 
@@ -226,19 +219,37 @@ char* buf_getstring(buffer* buf, unsigned int *retlen) {
 }
 
 /* Return a string as a newly allocated buffer */
-buffer * buf_getstringbuf(buffer *buf) {
+static buffer * buf_getstringbuf_int(buffer *buf, int incllen) {
 	buffer *ret = NULL;
 	unsigned int len = buf_getint(buf);
+	int extra = 0;
 	if (len > MAX_STRING_LEN) {
 		dropbear_exit("String too long");
 	}
-	ret = buf_new(len);
+	if (incllen) {
+		extra = 4;
+	}
+	ret = buf_new(len+extra);
+	if (incllen) {
+		buf_putint(ret, len);
+	}
 	memcpy(buf_getwriteptr(ret, len), buf_getptr(buf, len), len);
 	buf_incrpos(buf, len);
 	buf_incrlen(ret, len);
+	buf_setpos(ret, 0);
 	return ret;
 }
 
+/* Return a string as a newly allocated buffer */
+buffer * buf_getstringbuf(buffer *buf) {
+	return buf_getstringbuf_int(buf, 0);
+}
+
+/* Returns a string in a new buffer, including the length */
+buffer * buf_getbuf(buffer *buf) {
+	return buf_getstringbuf_int(buf, 1);
+}
+
 /* Just increment the buffer position the same as if we'd used buf_getstring,
  * but don't bother copying/malloc()ing for it */
 void buf_eatstring(buffer *buf) {
@@ -287,18 +298,18 @@ void buf_putbytes(buffer *buf, const unsigned char *bytes, unsigned int len) {
 /* for our purposes we only need positive (or 0) numbers, so will
  * fail if we get negative numbers */
 void buf_putmpint(buffer* buf, mp_int * mp) {
-
+	size_t written;
 	unsigned int len, pad = 0;
 	TRACE2(("enter buf_putmpint"))
 
 	dropbear_assert(mp != NULL);
 
-	if (SIGN(mp) == MP_NEG) {
+	if (mp_isneg(mp)) {
 		dropbear_exit("negative bignum");
 	}
 
 	/* zero check */
-	if (USED(mp) == 1 && DIGIT(mp, 0) == 0) {
+	if (mp_iszero(mp)) {
 		len = 0;
 	} else {
 		/* SSH spec requires padding for mpints with the MSB set, this code
@@ -319,10 +330,10 @@ void buf_putmpint(buffer* buf, mp_int * mp) {
 		if (pad) {
 			buf_putbyte(buf, 0x00);
 		}
-		if (mp_to_unsigned_bin(mp, buf_getwriteptr(buf, len-pad)) != MP_OKAY) {
+		if (mp_to_ubin(mp, buf_getwriteptr(buf, len-pad), len-pad, &written) != MP_OKAY) {
 			dropbear_exit("mpint error");
 		}
-		buf_incrwritepos(buf, len-pad);
+		buf_incrwritepos(buf, written);
 	}
 
 	TRACE2(("leave buf_putmpint"))
@@ -350,7 +361,7 @@ int buf_getmpint(buffer* buf, mp_int* mp) {
 		return DROPBEAR_FAILURE;
 	}
 
-	if (mp_read_unsigned_bin(mp, buf_getptr(buf, len), len) != MP_OKAY) {
+	if (mp_from_ubin(mp, buf_getptr(buf, len), len) != MP_OKAY) {
 		return DROPBEAR_FAILURE;
 	}
 

buffer.h

@@ -49,7 +49,8 @@ buffer* buf_newcopy(const buffer* buf);
 void buf_setlen(buffer* buf, unsigned int len);
 void buf_incrlen(buffer* buf, unsigned int incr);
 void buf_setpos(buffer* buf, unsigned int pos);
-void buf_incrpos(buffer* buf, int incr); /* -ve is ok, to go backwards */
+void buf_incrpos(buffer* buf, unsigned int incr);
+void buf_decrpos(buffer* buf, unsigned int decr);
 void buf_incrwritepos(buffer* buf, unsigned int incr);
 unsigned char buf_getbyte(buffer* buf);
 unsigned char buf_getbool(buffer* buf);
@@ -58,6 +59,7 @@ unsigned char* buf_getptr(const buffer* buf, unsigned int len);
 unsigned char* buf_getwriteptr(const buffer* buf, unsigned int len);
 char* buf_getstring(buffer* buf, unsigned int *retlen);
 buffer * buf_getstringbuf(buffer *buf);
+buffer * buf_getbuf(buffer *buf);
 void buf_eatstring(buffer *buf);
 void buf_putint(buffer* buf, unsigned int val);
 void buf_putstring(buffer* buf, const char* str, unsigned int len);

chachapoly.c

@@ -0,0 +1,148 @@
+/*
+ * Dropbear SSH
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * Copyright (c) 2020 by Vladislav Grishenko
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "algo.h"
+#include "dbutil.h"
+#include "chachapoly.h"
+
+#if DROPBEAR_CHACHA20POLY1305
+
+#define CHACHA20_KEY_LEN 32
+#define CHACHA20_BLOCKSIZE 8
+#define POLY1305_KEY_LEN 32
+#define POLY1305_TAG_LEN 16
+
+static const struct ltc_cipher_descriptor dummy = {.name = NULL};
+
+static const struct dropbear_hash dropbear_chachapoly_mac =
+	{NULL, POLY1305_KEY_LEN, POLY1305_TAG_LEN};
+
+const struct dropbear_cipher dropbear_chachapoly =
+	{&dummy, CHACHA20_KEY_LEN*2, CHACHA20_BLOCKSIZE};
+
+static int dropbear_chachapoly_start(int UNUSED(cipher), const unsigned char* UNUSED(IV),
+			const unsigned char *key, int keylen,
+			int UNUSED(num_rounds), dropbear_chachapoly_state *state) {
+	int err;
+
+	TRACE2(("enter dropbear_chachapoly_start"))
+
+	if (keylen != CHACHA20_KEY_LEN*2) {
+		return CRYPT_ERROR;
+	}
+
+	if ((err = chacha_setup(&state->chacha, key,
+				CHACHA20_KEY_LEN, 20)) != CRYPT_OK) {
+		return err;
+	}
+
+	if ((err = chacha_setup(&state->header, key + CHACHA20_KEY_LEN,
+				CHACHA20_KEY_LEN, 20) != CRYPT_OK)) {
+		return err;
+	}
+
+	TRACE2(("leave dropbear_chachapoly_start"))
+	return CRYPT_OK;
+}
+
+static int dropbear_chachapoly_crypt(unsigned int seq,
+			const unsigned char *in, unsigned char *out,
+			unsigned long len, unsigned long taglen,
+			dropbear_chachapoly_state *state, int direction) {
+	poly1305_state poly;
+	unsigned char seqbuf[8], key[POLY1305_KEY_LEN], tag[POLY1305_TAG_LEN];
+	int err;
+
+	TRACE2(("enter dropbear_chachapoly_crypt"))
+
+	if (len < 4 || taglen != POLY1305_TAG_LEN) {
+		return CRYPT_ERROR;
+	}
+
+	STORE64H((uint64_t)seq, seqbuf);
+	chacha_ivctr64(&state->chacha, seqbuf, sizeof(seqbuf), 0);
+	if ((err = chacha_keystream(&state->chacha, key, sizeof(key))) != CRYPT_OK) {
+		return err;
+	}
+
+	poly1305_init(&poly, key, sizeof(key));
+	if (direction == LTC_DECRYPT) {
+		poly1305_process(&poly, in, len);
+		poly1305_done(&poly, tag, &taglen);
+		if (constant_time_memcmp(in + len, tag, taglen) != 0) {
+			return CRYPT_ERROR;
+		}
+	}
+
+	chacha_ivctr64(&state->header, seqbuf, sizeof(seqbuf), 0);
+	if ((err = chacha_crypt(&state->header, in, 4, out)) != CRYPT_OK) {
+		return err;
+	}
+
+	chacha_ivctr64(&state->chacha, seqbuf, sizeof(seqbuf), 1);
+	if ((err = chacha_crypt(&state->chacha, in + 4, len - 4, out + 4)) != CRYPT_OK) {
+		return err;
+	}
+
+	if (direction == LTC_ENCRYPT) {
+		poly1305_process(&poly, out, len);
+		poly1305_done(&poly, out + len, &taglen);
+	}
+
+	TRACE2(("leave dropbear_chachapoly_crypt"))
+	return CRYPT_OK;
+}
+
+static int dropbear_chachapoly_getlength(unsigned int seq,
+			const unsigned char *in, unsigned int *outlen,
+			unsigned long len, dropbear_chachapoly_state *state) {
+	unsigned char seqbuf[8], buf[4];
+	int err;
+
+	TRACE2(("enter dropbear_chachapoly_getlength"))
+
+	if (len < sizeof(buf)) {
+		return CRYPT_ERROR;
+	}
+
+	STORE64H((uint64_t)seq, seqbuf);
+	chacha_ivctr64(&state->header, seqbuf, sizeof(seqbuf), 0);
+	if ((err = chacha_crypt(&state->header, in, sizeof(buf), buf)) != CRYPT_OK) {
+		return err;
+	}
+
+	LOAD32H(*outlen, buf);
+
+	TRACE2(("leave dropbear_chachapoly_getlength"))
+	return CRYPT_OK;
+}
+
+const struct dropbear_cipher_mode dropbear_mode_chachapoly =
+	{(void *)dropbear_chachapoly_start, NULL, NULL,
+	 (void *)dropbear_chachapoly_crypt,
+	 (void *)dropbear_chachapoly_getlength, &dropbear_chachapoly_mac};
+
+#endif /* DROPBEAR_CHACHA20POLY1305 */

chachapoly.h

@@ -0,0 +1,44 @@
+/*
+ * Dropbear SSH
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * Copyright (c) 2020 by Vladislav Grishenko
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#ifndef DROPBEAR_DROPBEAR_CHACHAPOLY_H_
+#define DROPBEAR_DROPBEAR_CHACHAPOLY_H_
+
+#include "includes.h"
+#include "algo.h"
+
+#if DROPBEAR_CHACHA20POLY1305
+
+typedef struct {
+	chacha_state chacha;
+	chacha_state header;
+} dropbear_chachapoly_state;
+
+extern const struct dropbear_cipher dropbear_chachapoly;
+extern const struct dropbear_cipher_mode dropbear_mode_chachapoly;
+
+#endif /* DROPBEAR_CHACHA20POLY1305 */
+
+#endif /* DROPBEAR_DROPBEAR_CHACHAPOLY_H_ */

channel.h

@@ -60,6 +60,9 @@ struct Channel {
 	int readfd; /* read from insecure side, written to wire */
 	int errfd; /* used like writefd or readfd, depending if it's client or server.
 				  Doesn't exactly belong here, but is cleaner here */
+	int bidir_fd; /* a boolean indicating that writefd/readfd are the same
+			file descriptor (bidirectional), such as a network socket or PTY.
+			That is handled differently when closing FDs */
 	circbuffer *writebuf; /* data from the wire, for local consumption. Can be
 							 initially NULL */
 	circbuffer *extrabuf; /* extended-data for the program - used like writebuf
@@ -68,10 +71,9 @@ struct Channel {
 	/* whether close/eof messages have been exchanged */
 	int sent_close, recv_close;
 	int recv_eof, sent_eof;
-
-	/* Set after running the ChanType-specific close hander
-	 * to ensure we don't run it twice (nor type->checkclose()). */
-	int close_handler_done;
+	/* once flushing is set, readfd will close once no more data is available
+	(not waiting for EOF) */
+	int flushing;
 
 	struct dropbear_progress_connection *conn_pending;
 	int initconn; /* used for TCP forwarding, whether the channel has been
@@ -81,8 +83,6 @@ struct Channel {
 					   for this channel (and are awaiting a confirmation
 					   or failure). */
 
-	int flushing;
-
 	/* Used by client chansession to handle ~ escaping, NULL ignored otherwise */
 	void (*read_mangler)(const struct Channel*, const unsigned char* bytes, int *len);
 
@@ -93,15 +93,21 @@ struct Channel {
 
 struct ChanType {
 
-	int sepfds; /* Whether this channel has separate pipes for in/out or not */
 	const char *name;
+	/* Sets up the channel */
 	int (*inithandler)(struct Channel*);
-	int (*check_close)(const struct Channel*);
+	/* Called to check whether a channel should close, separately from the FD being EOF.
+	Used for noticing process exiting */
+	int (*check_close)(struct Channel*);
+	/* Handler for ssh_msg_channel_request */
 	void (*reqhandler)(struct Channel*);
+	/* Called prior to sending ssh_msg_channel_close, used for sending exit status */
 	void (*closehandler)(const struct Channel*);
+	/* Frees resources, called just prior to channel being removed */
+	void (*cleanup)(const struct Channel*);
 };
 
-/* Callback for connect_remote */
+/* Callback for connect_remote. errstring may be NULL if result == DROPBEAR_SUCCESS */
 void channel_connect_done(int result, int sock, void* user_data, const char* errstring);
 
 void chaninitialise(const struct ChanType *chantypes[]);

chansession.h

@@ -41,6 +41,9 @@ struct ChanSess {
 
 	char * cmd; /* command to exec */
 	pid_t pid; /* child process pid */
+	/* command that was sent by the client, if authorized_keys command= or
+	dropbear -c was used */
+	char *original_command;
 
 	/* pty details */
 	int master; /* the master terminal fd*/
@@ -72,10 +75,6 @@ struct ChanSess {
 	char * agentfile;
 	char * agentdir;
 #endif
-
-#if DROPBEAR_SVR_PUBKEY_OPTIONS_BUILT
-	char *original_command;
-#endif
 };
 
 struct ChildPid {

cli-agentfwd.c

@@ -47,11 +47,11 @@
 static int new_agent_chan(struct Channel * channel);
 
 const struct ChanType cli_chan_agent = {
-	0, /* sepfds */
 	"auth-agent@openssh.com",
 	new_agent_chan,
 	NULL,
 	NULL,
+	NULL,
 	NULL
 };
 
@@ -93,6 +93,7 @@ static int new_agent_chan(struct Channel * channel) {
 
 	channel->readfd = fd;
 	channel->writefd = fd;
+	channel->bidir_fd = 1;
 
 	return 0;
 }
@@ -254,11 +255,12 @@ void cli_load_agent_keys(m_list *ret_list) {
 }
 
 void agent_buf_sign(buffer *sigblob, sign_key *key, 
-		const buffer *data_buf) {
+		const buffer *data_buf, enum signature_type sigtype) {
 	buffer *request_data = NULL;
 	buffer *response = NULL;
 	unsigned int siglen;
 	int packet_type;
+	int flags = 0;
 	
 	/* Request format
 	byte			SSH2_AGENTC_SIGN_REQUEST
@@ -270,7 +272,12 @@ void agent_buf_sign(buffer *sigblob, sign_key *key,
 	buf_put_pub_key(request_data, key, key->type);
 	
 	buf_putbufstring(request_data, data_buf);
-	buf_putint(request_data, 0);
+#if DROPBEAR_RSA_SHA256
+	if (sigtype == DROPBEAR_SIGNATURE_RSA_SHA256) {
+		flags |= SSH_AGENT_RSA_SHA2_256;
+	}
+#endif
+	buf_putint(request_data, flags);
 	
 	response = agent_request(SSH2_AGENTC_SIGN_REQUEST, request_data);
 	

cli-auth.c

@@ -32,12 +32,6 @@
 #include "packet.h"
 #include "runopts.h"
 
-void cli_authinitialise() {
-
-	memset(&ses.authstate, 0, sizeof(ses.authstate));
-}
-
-
 /* Send a "none" auth request to get available methods */
 void cli_auth_getmethods() {
 	TRACE(("enter cli_auth_getmethods"))
@@ -267,6 +261,9 @@ void recv_msg_userauth_success() {
 	if DROPBEAR_CLI_IMMEDIATE_AUTH is set */
 
 	TRACE(("received msg_userauth_success"))
+	if (cli_opts.disable_trivial_auth && cli_ses.is_trivial_auth) {
+		dropbear_exit("trivial authentication not allowed");
+	}
 	/* Note: in delayed-zlib mode, setting authdone here 
 	 * will enable compression in the transport layer */
 	ses.authstate.authdone = 1;

cli-authinteract.c

@@ -114,6 +114,7 @@ void recv_msg_userauth_info_request() {
 	m_free(instruction);
 
 	for (i = 0; i < num_prompts; i++) {
+		cli_ses.is_trivial_auth = 0;
 		unsigned int response_len = 0;
 		prompt = buf_getstring(ses.payload, NULL);
 		cleantext(prompt);

cli-authpasswd.c

@@ -155,7 +155,7 @@ void cli_auth_password() {
 
 	encrypt_packet();
 	m_burn(password, strlen(password));
-
+	cli_ses.is_trivial_auth = 0;
 	TRACE(("leave cli_auth_password"))
 }
 #endif	/* DROPBEAR_CLI_PASSWORD_AUTH */

cli-authpubkey.c

@@ -33,7 +33,7 @@
 #include "agentfwd.h"
 
 #if DROPBEAR_CLI_PUBKEY_AUTH
-static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign);
+static void send_msg_userauth_pubkey(sign_key *key, enum signature_type sigtype, int realsign);
 
 /* Called when we receive a SSH_MSG_USERAUTH_FAILURE for a pubkey request.
  * We use it to remove the key we tried from the list */
@@ -59,13 +59,15 @@ void recv_msg_userauth_pk_ok() {
 	char* algotype = NULL;
 	unsigned int algolen;
 	enum signkey_type keytype;
+	enum signature_type sigtype;
 	unsigned int remotelen;
 
 	TRACE(("enter recv_msg_userauth_pk_ok"))
 
 	algotype = buf_getstring(ses.payload, &algolen);
-	keytype = signkey_type_from_name(algotype, algolen);
-	TRACE(("recv_msg_userauth_pk_ok: type %d", keytype))
+	sigtype = signature_type_from_name(algotype, algolen);
+	keytype = signkey_type_from_signature(sigtype);
+	TRACE(("recv_msg_userauth_pk_ok: type %d", sigtype))
 	m_free(algotype);
 
 	keybuf = buf_new(MAX_PUBKEY_SIZE);
@@ -112,7 +114,7 @@ void recv_msg_userauth_pk_ok() {
 		TRACE(("matching key"))
 		/* XXX TODO: if it's an encrypted key, here we ask for their
 		 * password */
-		send_msg_userauth_pubkey((sign_key*)iter->item, keytype, 1);
+		send_msg_userauth_pubkey((sign_key*)iter->item, sigtype, 1);
 	} else {
 		TRACE(("That was whacky. We got told that a key was valid, but it didn't match our list. Sounds like dodgy code on Dropbear's part"))
 	}
@@ -120,31 +122,32 @@ void recv_msg_userauth_pk_ok() {
 	TRACE(("leave recv_msg_userauth_pk_ok"))
 }
 
-void cli_buf_put_sign(buffer* buf, sign_key *key, int type, 
+static void cli_buf_put_sign(buffer* buf, sign_key *key, enum signature_type sigtype,
 			const buffer *data_buf) {
 #if DROPBEAR_CLI_AGENTFWD
+	/* TODO: rsa-sha256 agent */
 	if (key->source == SIGNKEY_SOURCE_AGENT) {
 		/* Format the agent signature ourselves, as buf_put_sign would. */
 		buffer *sigblob;
 		sigblob = buf_new(MAX_PUBKEY_SIZE);
-		agent_buf_sign(sigblob, key, data_buf);
+		agent_buf_sign(sigblob, key, data_buf, sigtype);
 		buf_putbufstring(buf, sigblob);
 		buf_free(sigblob);
 	} else 
 #endif /* DROPBEAR_CLI_AGENTFWD */
 	{
-		buf_put_sign(buf, key, type, data_buf);
+		buf_put_sign(buf, key, sigtype, data_buf);
 	}
 }
 
-/* TODO: make it take an agent reference to use as well */
-static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) {
+static void send_msg_userauth_pubkey(sign_key *key, enum signature_type sigtype, int realsign) {
 
 	const char *algoname = NULL;
 	unsigned int algolen;
 	buffer* sigbuf = NULL;
+	enum signkey_type keytype = signkey_type_from_signature(sigtype);
 
-	TRACE(("enter send_msg_userauth_pubkey"))
+	TRACE(("enter send_msg_userauth_pubkey sigtype %d", sigtype))
 	CHECKCLEARTOWRITE();
 
 	buf_putbyte(ses.writepayload, SSH_MSG_USERAUTH_REQUEST);
@@ -160,10 +163,9 @@ static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) {
 
 	buf_putbyte(ses.writepayload, realsign);
 
-	algoname = signkey_name_from_type(type, &algolen);
-
+	algoname = signature_name_from_type(sigtype, &algolen);
 	buf_putstring(ses.writepayload, algoname, algolen);
-	buf_put_pub_key(ses.writepayload, key, type);
+	buf_put_pub_key(ses.writepayload, key, keytype);
 
 	if (realsign) {
 		TRACE(("realsign"))
@@ -172,8 +174,9 @@ static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) {
 		sigbuf = buf_new(4 + ses.session_id->len + ses.writepayload->len);
 		buf_putbufstring(sigbuf, ses.session_id);
 		buf_putbytes(sigbuf, ses.writepayload->data, ses.writepayload->len);
-		cli_buf_put_sign(ses.writepayload, key, type, sigbuf);
+		cli_buf_put_sign(ses.writepayload, key, sigtype, sigbuf);
 		buf_free(sigbuf); /* Nothing confidential in the buffer */
+		cli_ses.is_trivial_auth = 0;
 	}
 
 	encrypt_packet();
@@ -182,7 +185,7 @@ static void send_msg_userauth_pubkey(sign_key *key, int type, int realsign) {
 
 /* Returns 1 if a key was tried */
 int cli_auth_pubkey() {
-
+	enum signature_type sigtype = DROPBEAR_SIGNATURE_NONE;
 	TRACE(("enter cli_auth_pubkey"))
 
 #if DROPBEAR_CLI_AGENTFWD
@@ -190,13 +193,79 @@ int cli_auth_pubkey() {
 		/* get the list of available keys from the agent */
 		cli_load_agent_keys(cli_opts.privkeys);
 		cli_opts.agent_keys_loaded = 1;
+		TRACE(("cli_auth_pubkey: agent keys loaded"))
 	}
 #endif
 
+	/* iterate through privkeys to remove ones not allowed in server-sig-algs */
+ 	while (cli_opts.privkeys->first) {
+		sign_key * key = (sign_key*)cli_opts.privkeys->first->item;
+		if (cli_ses.server_sig_algs) {
+#if DROPBEAR_RSA
+			if (key->type == DROPBEAR_SIGNKEY_RSA) {
+#if DROPBEAR_RSA_SHA256
+				if (buf_has_algo(cli_ses.server_sig_algs, SSH_SIGNATURE_RSA_SHA256) 
+						== DROPBEAR_SUCCESS) {
+					sigtype = DROPBEAR_SIGNATURE_RSA_SHA256;
+					TRACE(("server-sig-algs allows rsa sha256"))
+					break;
+				}
+#endif /* DROPBEAR_RSA_SHA256 */
+#if DROPBEAR_RSA_SHA1
+				if (buf_has_algo(cli_ses.server_sig_algs, SSH_SIGNKEY_RSA)
+						== DROPBEAR_SUCCESS) {
+					sigtype = DROPBEAR_SIGNATURE_RSA_SHA1;
+					TRACE(("server-sig-algs allows rsa sha1"))
+					break;
+				}
+#endif /* DROPBEAR_RSA_SHA256 */
+			} else
+#endif /* DROPBEAR_RSA */
+			{
+				/* Not RSA */
+				const char *name = NULL;
+				sigtype = signature_type_from_signkey(key->type);
+				name = signature_name_from_type(sigtype, NULL);
+				if (buf_has_algo(cli_ses.server_sig_algs, name)
+						== DROPBEAR_SUCCESS) {
+					TRACE(("server-sig-algs allows %s", name))
+					break;
+				}
+			}
+
+			/* No match, skip this key */
+			TRACE(("server-sig-algs no match keytype %d, skipping", key->type))
+			key = list_remove(cli_opts.privkeys->first);
+			sign_key_free(key); 
+			continue;
+		} else {
+			/* Server didn't provide a server-sig-algs list, we'll 
+			   assume all except rsa-sha256 are OK. */
+#if DROPBEAR_RSA
+			if (key->type == DROPBEAR_SIGNKEY_RSA) {
+#if DROPBEAR_RSA_SHA1
+				sigtype = DROPBEAR_SIGNATURE_RSA_SHA1;
+				TRACE(("no server-sig-algs, using rsa sha1"))
+				break;
+#else
+				/* only support rsa-sha256, skip this key */
+				TRACE(("no server-sig-algs, skipping rsa sha256"))
+				key = list_remove(cli_opts.privkeys->first);
+				sign_key_free(key); 
+				continue;
+#endif
+			} /* key->type == DROPBEAR_SIGNKEY_RSA */
+#endif /* DROPBEAR_RSA */
+			sigtype = signature_type_from_signkey(key->type);
+			TRACE(("no server-sig-algs, using key"))
+			break;
+		}
+	}
+
 	if (cli_opts.privkeys->first) {
 		sign_key * key = (sign_key*)cli_opts.privkeys->first->item;
 		/* Send a trial request */
-		send_msg_userauth_pubkey(key, key->type, 0);
+		send_msg_userauth_pubkey(key, sigtype, 0);
 		cli_ses.lastprivkey = key;
 		TRACE(("leave cli_auth_pubkey-success"))
 		return 1;

cli-chansession.c

@@ -46,12 +46,12 @@ static int cli_init_netcat(struct Channel *channel);
 static void cli_tty_setup(void);
 
 const struct ChanType clichansess = {
-	0, /* sepfds */
 	"session", /* name */
 	cli_initchansess, /* inithandler */
 	NULL, /* checkclosehandler */
 	cli_chansessreq, /* reqhandler */
 	cli_closechansess, /* closehandler */
+	NULL, /* cleanup */
 };
 
 static void cli_chansessreq(struct Channel *channel) {
@@ -343,6 +343,7 @@ static int cli_init_stdpipe_sess(struct Channel *channel) {
 	setnonblocking(STDERR_FILENO);
 
 	channel->extrabuf = cbuf_new(opts.recv_window);
+	channel->bidir_fd = 0;
 	return 0;
 }
 
@@ -382,12 +383,12 @@ static int cli_initchansess(struct Channel *channel) {
 #if DROPBEAR_CLI_NETCAT
 
 static const struct ChanType cli_chan_netcat = {
-	0, /* sepfds */
 	"direct-tcpip",
 	cli_init_netcat, /* inithandler */
 	NULL,
 	NULL,
-	cli_closechansess
+	cli_closechansess,
+	NULL,
 };
 
 void cli_send_netcat_request() {

cli-kex.c

@@ -46,6 +46,13 @@ void send_msg_kexdh_init() {
 	TRACE(("send_msg_kexdh_init()"))	
 
 	CHECKCLEARTOWRITE();
+
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing && fuzz.skip_kexmaths) {
+		return;
+	}
+#endif
+
 	buf_putbyte(ses.writepayload, SSH_MSG_KEXDH_INIT);
 	switch (ses.newkeys->algo_kex->mode) {
 #if DROPBEAR_NORMAL_DH
@@ -81,7 +88,7 @@ void send_msg_kexdh_init() {
 				}
 				cli_ses.curve25519_param = gen_kexcurve25519_param();
 			}
-			buf_putstring(ses.writepayload, (const char*)cli_ses.curve25519_param->pub, CURVE25519_LEN);
+			buf_putstring(ses.writepayload, cli_ses.curve25519_param->pub, CURVE25519_LEN);
 			break;
 #endif
 	}
@@ -94,16 +101,22 @@ void send_msg_kexdh_init() {
 void recv_msg_kexdh_reply() {
 
 	sign_key *hostkey = NULL;
-	unsigned int type, keybloblen;
+	unsigned int keytype, keybloblen;
 	unsigned char* keyblob = NULL;
 
 	TRACE(("enter recv_msg_kexdh_reply"))
+	
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing && fuzz.skip_kexmaths) {
+		return;
+	}
+#endif
 
 	if (cli_ses.kex_state != KEXDH_INIT_SENT) {
 		dropbear_exit("Received out-of-order kexdhreply");
 	}
-	type = ses.newkeys->algo_hostkey;
-	TRACE(("type is %d", type))
+	keytype = ses.newkeys->algo_hostkey;
+	TRACE(("keytype is %d", keytype))
 
 	hostkey = new_sign_key();
 	keybloblen = buf_getint(ses.payload);
@@ -114,7 +127,7 @@ void recv_msg_kexdh_reply() {
 		checkhostkey(keyblob, keybloblen);
 	}
 
-	if (buf_get_pub_key(ses.payload, hostkey, &type) != DROPBEAR_SUCCESS) {
+	if (buf_get_pub_key(ses.payload, hostkey, &keytype) != DROPBEAR_SUCCESS) {
 		TRACE(("failed getting pubkey"))
 		dropbear_exit("Bad KEX packet");
 	}
@@ -155,10 +168,12 @@ void recv_msg_kexdh_reply() {
 #endif
 	}
 
+#if DROPBEAR_NORMAL_DH
 	if (cli_ses.dh_param) {
 		free_kexdh_param(cli_ses.dh_param);
 		cli_ses.dh_param = NULL;
 	}
+#endif
 #if DROPBEAR_ECDH
 	if (cli_ses.ecdh_param) {
 		free_kexecdh_param(cli_ses.ecdh_param);
@@ -173,7 +188,8 @@ void recv_msg_kexdh_reply() {
 #endif
 
 	cli_ses.param_kex_algo = NULL;
-	if (buf_verify(ses.payload, hostkey, ses.hash) != DROPBEAR_SUCCESS) {
+	if (buf_verify(ses.payload, hostkey, ses.newkeys->algo_signature, 
+			ses.hash) != DROPBEAR_SUCCESS) {
 		dropbear_exit("Bad hostkey signature");
 	}
 
@@ -410,3 +426,38 @@ out:
 	}
 	m_free(fingerprint);
 }
+
+void recv_msg_ext_info(void) {
+	/* This message is not client-specific in the protocol but Dropbear only handles
+	a server-sent message at present. */
+	unsigned int num_ext;
+	unsigned int i;
+
+	TRACE(("enter recv_msg_ext_info"))
+
+	/* Must be after the first SSH_MSG_NEWKEYS */
+	TRACE(("last %d, donefirst %d, donescond %d", ses.lastpacket, ses.kexstate.donefirstkex, ses.kexstate.donesecondkex))
+	if (!(ses.lastpacket == SSH_MSG_NEWKEYS && !ses.kexstate.donesecondkex)) {
+		TRACE(("leave recv_msg_ext_info: ignoring packet received at the wrong time"))
+		return;
+	}
+
+	num_ext = buf_getint(ses.payload);
+	TRACE(("received SSH_MSG_EXT_INFO with %d items", num_ext))
+
+	for (i = 0; i < num_ext; i++) {
+		unsigned int name_len;
+		char *ext_name = buf_getstring(ses.payload, &name_len);
+		TRACE(("extension %d name '%s'", i, ext_name))
+		if (cli_ses.server_sig_algs == NULL
+				&& name_len == strlen(SSH_SERVER_SIG_ALGS)
+				&& strcmp(ext_name, SSH_SERVER_SIG_ALGS) == 0) {
+			cli_ses.server_sig_algs = buf_getbuf(ses.payload);
+		} else {
+			/* valid extension values could be >MAX_STRING_LEN */
+			buf_eatstring(ses.payload);
+		}
+		m_free(ext_name);
+	}
+	TRACE(("leave recv_msg_ext_info"))
+}

cli-main.c

@@ -31,9 +31,7 @@
 #include "dbrandom.h"
 #include "crypto_desc.h"
 #include "netio.h"
-
-static void cli_dropbear_exit(int exitcode, const char* format, va_list param) ATTRIB_NORETURN;
-static void cli_dropbear_log(int priority, const char* format, va_list param);
+#include "fuzz.h"
 
 #if DROPBEAR_CLI_PROXYCMD
 static void cli_proxy_cmd(int *sock_in, int *sock_out, pid_t *pid_out);
@@ -49,6 +47,7 @@ int main(int argc, char ** argv) {
 
 	int sock_in, sock_out;
 	struct dropbear_progress_connection *progress = NULL;
+	pid_t proxy_cmd_pid = 0;
 
 	_dropbear_exit = cli_dropbear_exit;
 	_dropbear_log = cli_dropbear_log;
@@ -73,7 +72,6 @@ int main(int argc, char ** argv) {
 		dropbear_exit("signal() error");
 	}
 
-	pid_t proxy_cmd_pid = 0;
 #if DROPBEAR_CLI_PROXYCMD
 	if (cli_opts.proxycmd) {
 		cli_proxy_cmd(&sock_in, &sock_out, &proxy_cmd_pid);
@@ -98,51 +96,6 @@ int main(int argc, char ** argv) {
 }
 #endif /* DBMULTI stuff */
 
-static void cli_dropbear_exit(int exitcode, const char* format, va_list param) {
-	char exitmsg[150];
-	char fullmsg[300];
-
-	/* Note that exit message must be rendered before session cleanup */
-
-	/* Render the formatted exit message */
-	vsnprintf(exitmsg, sizeof(exitmsg), format, param);
-
-	/* Add the prefix depending on session/auth state */
-	if (!ses.init_done) {
-		snprintf(fullmsg, sizeof(fullmsg), "Exited: %s", exitmsg);
-	} else {
-		snprintf(fullmsg, sizeof(fullmsg), 
-				"Connection to %s@%s:%s exited: %s", 
-				cli_opts.username, cli_opts.remotehost, 
-				cli_opts.remoteport, exitmsg);
-	}
-
-	/* Do the cleanup first, since then the terminal will be reset */
-	session_cleanup();
-	/* Avoid printing onwards from terminal cruft */
-	fprintf(stderr, "\n");
-
-	dropbear_log(LOG_INFO, "%s", fullmsg);
-	exit(exitcode);
-}
-
-static void cli_dropbear_log(int priority,
-		const char* format, va_list param) {
-
-	char printbuf[1024];
-
-	vsnprintf(printbuf, sizeof(printbuf), format, param);
-
-#ifndef DISABLE_SYSLOG
-	if (opts.usingsyslog) {
-		syslog(priority, "%s", printbuf);
-	}
-#endif
-
-	fprintf(stderr, "%s: %s\n", cli_opts.progname, printbuf);
-	fflush(stderr);
-}
-
 static void exec_proxy_cmd(const void *user_data_cmd) {
 	const char *cmd = user_data_cmd;
 	char *usershell;
@@ -192,4 +145,5 @@ static void kill_proxy_sighandler(int UNUSED(signo)) {
 	kill_proxy_command();
 	_exit(1);
 }
+
 #endif /* DROPBEAR_CLI_PROXYCMD */

cli-runopts.c

@@ -79,7 +79,7 @@ static void printhelp() {
 #if DROPBEAR_CLI_REMOTETCPFWD
 					"-R <[listenaddress:]listenport:remotehost:remoteport> Remote port forwarding\n"
 #endif
-					"-W <receive_window_buffer> (default %d, larger may be faster, max 1MB)\n"
+					"-W <receive_window_buffer> (default %d, larger may be faster, max 10MB)\n"
 					"-K <keepalive>  (0 is never, default %d)\n"
 					"-I <idle_timeout>  (0 is never, default %d)\n"
 #if DROPBEAR_CLI_NETCAT
@@ -152,6 +152,7 @@ void cli_getopts(int argc, char ** argv) {
 #if DROPBEAR_CLI_ANYTCPFWD
 	cli_opts.exit_on_fwd_failure = 0;
 #endif
+	cli_opts.disable_trivial_auth = 0;
 #if DROPBEAR_CLI_LOCALTCPFWD
 	cli_opts.localfwds = list_new();
 	opts.listen_fwd_all = 0;
@@ -214,7 +215,7 @@ void cli_getopts(int argc, char ** argv) {
 					cli_opts.always_accept_key = 1;
 					break;
 				case 'p': /* remoteport */
-					next = &cli_opts.remoteport;
+					next = (char**)&cli_opts.remoteport;
 					break;
 #if DROPBEAR_CLI_PUBKEY_AUTH
 				case 'i': /* an identityfile */
@@ -378,6 +379,11 @@ void cli_getopts(int argc, char ** argv) {
 		}
 	}
 
+#if DROPBEAR_USER_ALGO_LIST
+	/* -c help doesn't need a hostname */
+	parse_ciphers_macs();
+#endif
+
 	/* Done with options/flags; now handle the hostname (which may not
 	 * start with a hyphen) and optional command */
 
@@ -408,10 +414,6 @@ void cli_getopts(int argc, char ** argv) {
 
 	/* And now a few sanity checks and setup */
 
-#if DROPBEAR_USER_ALGO_LIST
-	parse_ciphers_macs();
-#endif
-
 #if DROPBEAR_CLI_PROXYCMD                                                                                                                                   
 	if (cli_opts.proxycmd) {
 		/* To match the common path of m_freeing it */
@@ -449,12 +451,9 @@ void cli_getopts(int argc, char ** argv) {
 			&& cli_opts.no_cmd == 0) {
 		dropbear_exit("Command required for -f");
 	}
-	
+
 	if (recv_window_arg) {
-		opts.recv_window = atol(recv_window_arg);
-		if (opts.recv_window == 0 || opts.recv_window > MAX_RECV_WINDOW) {
-			dropbear_exit("Bad recv window '%s'", recv_window_arg);
-		}
+		parse_recv_window(recv_window_arg);
 	}
 	if (keepalive_arg) {
 		unsigned int val;
@@ -888,9 +887,11 @@ static void add_extendedopt(const char* origstr) {
 #if DROPBEAR_CLI_ANYTCPFWD
 			"\tExitOnForwardFailure\n"
 #endif
+			"\tDisableTrivialAuth\n"
 #ifndef DISABLE_SYSLOG
 			"\tUseSyslog\n"
 #endif
+			"\tPort\n"
 		);
 		exit(EXIT_SUCCESS);
 	}
@@ -909,5 +910,15 @@ static void add_extendedopt(const char* origstr) {
 	}
 #endif
 
+	if (match_extendedopt(&optstr, "Port") == DROPBEAR_SUCCESS) {
+		cli_opts.remoteport = optstr;
+		return;
+	}
+
+	if (match_extendedopt(&optstr, "DisableTrivialAuth") == DROPBEAR_SUCCESS) {
+		cli_opts.disable_trivial_auth = parse_flag_value(optstr);
+		return;
+	}
+
 	dropbear_log(LOG_WARNING, "Ignoring unknown configuration option '%s'", origstr);
 }

cli-session.c

@@ -81,6 +81,7 @@ static const packettype cli_packettypes[] = {
 	{SSH_MSG_REQUEST_SUCCESS, ignore_recv_response},
 	{SSH_MSG_REQUEST_FAILURE, ignore_recv_response},
 #endif
+	{SSH_MSG_EXT_INFO, recv_msg_ext_info},
 	{0, NULL} /* End */
 };
 
@@ -164,6 +165,7 @@ static void cli_session_init(pid_t proxy_cmd_pid) {
 	/* Auth */
 	cli_ses.lastprivkey = NULL;
 	cli_ses.lastauthtype = 0;
+	cli_ses.is_trivial_auth = 1;
 
 	/* For printing "remote host closed" for the user */
 	ses.remoteclosed = cli_remoteclosed;
@@ -244,6 +246,9 @@ static void cli_sessionloop() {
 			/* We've got the transport layer sorted, we now need to request
 			 * userauth */
 			send_msg_service_request(SSH_SERVICE_USERAUTH);
+			/* We aren't using any "implicit server authentication" methods,
+			so don't need to wait for a response for SSH_SERVICE_USERAUTH
+			before sending the auth messages (rfc4253 10) */
 			cli_auth_getmethods();
 			cli_ses.state = USERAUTH_REQ_SENT;
 			TRACE(("leave cli_sessionloop: sent userauth methods req"))
@@ -351,11 +356,19 @@ static void cli_session_cleanup(void) {
 	(void)fcntl(cli_ses.stdoutcopy, F_SETFL, cli_ses.stdoutflags);
 	(void)fcntl(cli_ses.stderrcopy, F_SETFL, cli_ses.stderrflags);
 
-	cli_tty_cleanup();
+	/* Don't leak */
+	m_close(cli_ses.stdincopy);
+	m_close(cli_ses.stdoutcopy);
+	m_close(cli_ses.stderrcopy);
 
+	cli_tty_cleanup();
+	if (cli_ses.server_sig_algs) {
+		buf_free(cli_ses.server_sig_algs);
+	}
 }
 
 static void cli_finished() {
+	TRACE(("cli_finished()"))
 
 	session_cleanup();
 	fprintf(stderr, "Connection to %s@%s:%s closed.\n", cli_opts.username,
@@ -399,7 +412,75 @@ void cleantext(char* dirtytext) {
 }
 
 static void recv_msg_global_request_cli(void) {
-	TRACE(("recv_msg_global_request_cli"))
-	/* Send a proper rejection */
-	send_msg_request_failure();
+	unsigned int wantreply = 0;
+
+	buf_eatstring(ses.payload);
+	wantreply = buf_getbool(ses.payload);
+
+	TRACE(("recv_msg_global_request_cli: want_reply: %u", wantreply));
+
+	if (wantreply) {
+		/* Send a proper rejection */
+		send_msg_request_failure();
+	}
 }
+
+void cli_dropbear_exit(int exitcode, const char* format, va_list param) {
+	char exitmsg[150];
+	char fullmsg[300];
+
+	/* Note that exit message must be rendered before session cleanup */
+
+	/* Render the formatted exit message */
+	vsnprintf(exitmsg, sizeof(exitmsg), format, param);
+	TRACE(("Exited, cleaning up: %s", exitmsg))
+
+	/* Add the prefix depending on session/auth state */
+	if (!ses.init_done) {
+		snprintf(fullmsg, sizeof(fullmsg), "Exited: %s", exitmsg);
+	} else {
+		snprintf(fullmsg, sizeof(fullmsg), 
+				"Connection to %s@%s:%s exited: %s", 
+				cli_opts.username, cli_opts.remotehost, 
+				cli_opts.remoteport, exitmsg);
+	}
+
+	/* Do the cleanup first, since then the terminal will be reset */
+	session_cleanup();
+	
+#if DROPBEAR_FUZZ
+    if (fuzz.do_jmp) {
+        longjmp(fuzz.jmp, 1);
+    }
+#endif
+
+	/* Avoid printing onwards from terminal cruft */
+	fprintf(stderr, "\n");
+
+	dropbear_log(LOG_INFO, "%s", fullmsg);
+
+	exit(exitcode);
+}
+
+void cli_dropbear_log(int priority, const char* format, va_list param) {
+
+	char printbuf[1024];
+	const char *name;
+
+	name = cli_opts.progname;
+	if (!name) {
+		name = "dbclient";
+	}
+
+	vsnprintf(printbuf, sizeof(printbuf), format, param);
+
+#ifndef DISABLE_SYSLOG
+	if (opts.usingsyslog) {
+		syslog(priority, "%s", printbuf);
+	}
+#endif
+
+	fprintf(stderr, "%s: %s\n", name, printbuf);
+	fflush(stderr);
+}
+

cli-tcpfwd.c

@@ -35,11 +35,11 @@
 static int newtcpforwarded(struct Channel * channel);
 
 const struct ChanType cli_chan_tcpremote = {
-	1, /* sepfds */
 	"forwarded-tcpip",
 	newtcpforwarded,
 	NULL,
 	NULL,
+	NULL,
 	NULL
 };
 #endif
@@ -50,11 +50,11 @@ static int cli_localtcp(const char* listenaddr,
 		const char* remoteaddr,
 		unsigned int remoteport);
 static const struct ChanType cli_chan_tcplocal = {
-	1, /* sepfds */
 	"direct-tcpip",
 	tcp_prio_inithandler,
 	NULL,
 	NULL,
+	NULL,
 	NULL
 };
 #endif
@@ -135,7 +135,7 @@ static int cli_localtcp(const char* listenaddr,
 	tcpinfo->chantype = &cli_chan_tcplocal;
 	tcpinfo->tcp_type = direct;
 
-	ret = listen_tcpfwd(tcpinfo);
+	ret = listen_tcpfwd(tcpinfo, NULL);
 
 	if (ret == DROPBEAR_FAILURE) {
 		m_free(tcpinfo);
@@ -271,12 +271,12 @@ static int newtcpforwarded(struct Channel * channel) {
                 origaddr, origport);
 		goto out;
 	}
-	
+
+	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
+
 	snprintf(portstring, sizeof(portstring), "%u", fwd->connectport);
 	channel->conn_pending = connect_remote(fwd->connectaddr, portstring, channel_connect_done, channel, NULL, NULL);
 
-	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
-	
 	err = SSH_OPEN_IN_PROGRESS;
 
 out:

common-algo.c

@@ -30,6 +30,9 @@
 #include "dh_groups.h"
 #include "ltc_prng.h"
 #include "ecc.h"
+#include "gcm.h"
+#include "chachapoly.h"
+#include "ssh.h"
 
 /* This file (algo.c) organises the ciphers which can be used, and is used to
  * decide which ciphers/hashes/compression/signing to use during key exchange*/
@@ -61,10 +64,6 @@ static const struct dropbear_cipher dropbear_aes256 =
 static const struct dropbear_cipher dropbear_aes128 = 
 	{&aes_desc, 16, 16};
 #endif
-#if DROPBEAR_BLOWFISH
-static const struct dropbear_cipher dropbear_blowfish = 
-	{&blowfish_desc, 16, 8};
-#endif
 #if DROPBEAR_TWOFISH256
 static const struct dropbear_cipher dropbear_twofish256 = 
 	{&twofish_desc, 32, 16};
@@ -86,11 +85,11 @@ const struct dropbear_cipher dropbear_nocipher =
  * about the symmetric_CBC vs symmetric_CTR cipher_state pointer */
 #if DROPBEAR_ENABLE_CBC_MODE
 const struct dropbear_cipher_mode dropbear_mode_cbc =
-	{(void*)cbc_start, (void*)cbc_encrypt, (void*)cbc_decrypt};
+	{(void*)cbc_start, (void*)cbc_encrypt, (void*)cbc_decrypt, NULL, NULL, NULL};
 #endif /* DROPBEAR_ENABLE_CBC_MODE */
 
 const struct dropbear_cipher_mode dropbear_mode_none =
-	{void_start, void_cipher, void_cipher};
+	{void_start, void_cipher, void_cipher, NULL, NULL, NULL};
 
 #if DROPBEAR_ENABLE_CTR_MODE
 /* a wrapper to make ctr_start and cbc_start look the same */
@@ -101,7 +100,7 @@ static int dropbear_big_endian_ctr_start(int cipher,
 	return ctr_start(cipher, IV, key, keylen, num_rounds, CTR_COUNTER_BIG_ENDIAN, ctr);
 }
 const struct dropbear_cipher_mode dropbear_mode_ctr =
-	{(void*)dropbear_big_endian_ctr_start, (void*)ctr_encrypt, (void*)ctr_decrypt};
+	{(void*)dropbear_big_endian_ctr_start, (void*)ctr_encrypt, (void*)ctr_decrypt, NULL, NULL, NULL};
 #endif /* DROPBEAR_ENABLE_CTR_MODE */
 
 /* Mapping of ssh hashes to libtomcrypt hashes, including keysize etc.
@@ -137,6 +136,19 @@ const struct dropbear_hash dropbear_nohash =
  * that is also supported by the server will get used. */
 
 algo_type sshciphers[] = {
+#if DROPBEAR_CHACHA20POLY1305
+	{"chacha20-poly1305@openssh.com", 0, &dropbear_chachapoly, 1, &dropbear_mode_chachapoly},
+#endif
+
+#if DROPBEAR_ENABLE_GCM_MODE
+#if DROPBEAR_AES128
+	{"aes128-gcm@openssh.com", 0, &dropbear_aes128, 1, &dropbear_mode_gcm},
+#endif
+#if DROPBEAR_AES256
+	{"aes256-gcm@openssh.com", 0, &dropbear_aes256, 1, &dropbear_mode_gcm},
+#endif
+#endif /* DROPBEAR_ENABLE_GCM_MODE */
+
 #if DROPBEAR_ENABLE_CTR_MODE
 #if DROPBEAR_AES128
 	{"aes128-ctr", 0, &dropbear_aes128, 1, &dropbear_mode_ctr},
@@ -169,15 +181,18 @@ algo_type sshciphers[] = {
 #if DROPBEAR_TWOFISH128
 	{"twofish128-cbc", 0, &dropbear_twofish128, 1, &dropbear_mode_cbc},
 #endif
+#endif /* DROPBEAR_ENABLE_CBC_MODE */
+
 #if DROPBEAR_3DES
+#if DROPBEAR_ENABLE_CTR_MODE
 	{"3des-ctr", 0, &dropbear_3des, 1, &dropbear_mode_ctr},
 #endif
-#if DROPBEAR_3DES
+#if DROPBEAR_ENABLE_CBC_MODE
 	{"3des-cbc", 0, &dropbear_3des, 1, &dropbear_mode_cbc},
 #endif
-#if DROPBEAR_BLOWFISH
-	{"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc},
-#endif
+#endif /* DROPBEAR_3DES */
+
+#if DROPBEAR_ENABLE_CBC_MODE
 #endif /* DROPBEAR_ENABLE_CBC_MODE */
 	{NULL, 0, NULL, 0, NULL}
 };
@@ -221,23 +236,37 @@ algo_type ssh_nocompress[] = {
 	{NULL, 0, NULL, 0, NULL}
 };
 
-algo_type sshhostkey[] = {
+algo_type sigalgs[] = {
+#if DROPBEAR_ED25519
+	{"ssh-ed25519", DROPBEAR_SIGNATURE_ED25519, NULL, 1, NULL},
+#if DROPBEAR_SK_ED25519
+	{"sk-ssh-ed25519@openssh.com", DROPBEAR_SIGNATURE_SK_ED25519, NULL, 1, NULL},
+#endif
+#endif
 #if DROPBEAR_ECDSA
 #if DROPBEAR_ECC_256
-	{"ecdsa-sha2-nistp256", DROPBEAR_SIGNKEY_ECDSA_NISTP256, NULL, 1, NULL},
+	{"ecdsa-sha2-nistp256", DROPBEAR_SIGNATURE_ECDSA_NISTP256, NULL, 1, NULL},
 #endif
 #if DROPBEAR_ECC_384
-	{"ecdsa-sha2-nistp384", DROPBEAR_SIGNKEY_ECDSA_NISTP384, NULL, 1, NULL},
+	{"ecdsa-sha2-nistp384", DROPBEAR_SIGNATURE_ECDSA_NISTP384, NULL, 1, NULL},
 #endif
 #if DROPBEAR_ECC_521
-	{"ecdsa-sha2-nistp521", DROPBEAR_SIGNKEY_ECDSA_NISTP521, NULL, 1, NULL},
+	{"ecdsa-sha2-nistp521", DROPBEAR_SIGNATURE_ECDSA_NISTP521, NULL, 1, NULL},
+#endif
+#if DROPBEAR_SK_ECDSA
+	{"sk-ecdsa-sha2-nistp256@openssh.com", DROPBEAR_SIGNATURE_SK_ECDSA_NISTP256, NULL, 1, NULL},
 #endif
 #endif
 #if DROPBEAR_RSA
-	{"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1, NULL},
+#if DROPBEAR_RSA_SHA256
+	{"rsa-sha2-256", DROPBEAR_SIGNATURE_RSA_SHA256, NULL, 1, NULL},
+#endif
+#if DROPBEAR_RSA_SHA1
+	{"ssh-rsa", DROPBEAR_SIGNATURE_RSA_SHA1, NULL, 1, NULL},
+#endif
 #endif
 #if DROPBEAR_DSS
-	{"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1, NULL},
+	{"ssh-dss", DROPBEAR_SIGNATURE_DSS, NULL, 1, NULL},
 #endif
 	{NULL, 0, NULL, 0, NULL}
 };
@@ -255,8 +284,6 @@ static const struct dropbear_kex kex_dh_group14_sha256 = {DROPBEAR_KEX_NORMAL_DH
 static const struct dropbear_kex kex_dh_group16_sha512 = {DROPBEAR_KEX_NORMAL_DH, dh_p_16, DH_P_16_LEN, NULL, &sha512_desc };
 #endif
 
-/* These can't be const since dropbear_ecc_fill_dp() fills out
- ecc_curve at runtime */
 #if DROPBEAR_ECDH
 #if DROPBEAR_ECC_256
 static const struct dropbear_kex kex_ecdh_nistp256 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp256, &sha256_desc };
@@ -274,6 +301,7 @@ static const struct dropbear_kex kex_ecdh_nistp521 = {DROPBEAR_KEX_ECDH, NULL, 0
 static const struct dropbear_kex kex_curve25519 = {DROPBEAR_KEX_CURVE25519, NULL, 0, NULL, &sha256_desc };
 #endif
 
+/* data == NULL for non-kex algorithm identifiers */
 algo_type sshkex[] = {
 #if DROPBEAR_CURVE25519
 	{"curve25519-sha256", 0, &kex_curve25519, 1, NULL},
@@ -303,49 +331,122 @@ algo_type sshkex[] = {
 	{"diffie-hellman-group16-sha512", 0, &kex_dh_group16_sha512, 1, NULL},
 #endif
 #if DROPBEAR_KEXGUESS2
-	{KEXGUESS2_ALGO_NAME, KEXGUESS2_ALGO_ID, NULL, 1, NULL},
+	{KEXGUESS2_ALGO_NAME, 0, NULL, 1, NULL},
+#endif
+#if DROPBEAR_EXT_INFO
+#if DROPBEAR_CLIENT
+	/* Set unusable by svr_algos_initialise() */
+	{SSH_EXT_INFO_C, 0, NULL, 1, NULL},
+#endif
 #endif
 	{NULL, 0, NULL, 0, NULL}
 };
 
-/* algolen specifies the length of algo, algos is our local list to match
- * against.
- * Returns DROPBEAR_SUCCESS if we have a match for algo, DROPBEAR_FAILURE
- * otherwise */
-int have_algo(const char* algo, size_t algolen, const algo_type algos[]) {
-
-	int i;
-
-	for (i = 0; algos[i].name != NULL; i++) {
-		if (strlen(algos[i].name) == algolen
-				&& (strncmp(algos[i].name, algo, algolen) == 0)) {
-			return DROPBEAR_SUCCESS;
-		}
-	}
-
-	return DROPBEAR_FAILURE;
-}
-
 /* Output a comma separated list of algorithms to a buffer */
-void buf_put_algolist(buffer * buf, const algo_type localalgos[]) {
-
+void buf_put_algolist_all(buffer * buf, const algo_type localalgos[], int useall) {
 	unsigned int i, len;
 	unsigned int donefirst = 0;
-	buffer *algolist = NULL;
+	unsigned int startpos;
 
-	algolist = buf_new(300);
+	startpos = buf->pos;
+	/* Placeholder for length */
+	buf_putint(buf, 0); 
 	for (i = 0; localalgos[i].name != NULL; i++) {
-		if (localalgos[i].usable) {
-			if (donefirst)
-				buf_putbyte(algolist, ',');
+		if (localalgos[i].usable || useall) {
+			if (donefirst) {
+				buf_putbyte(buf, ',');
+			}
 			donefirst = 1;
 			len = strlen(localalgos[i].name);
-			buf_putbytes(algolist, (const unsigned char *) localalgos[i].name, len);
+			buf_putbytes(buf, (const unsigned char *) localalgos[i].name, len);
 		}
 	}
-	buf_putstring(buf, (const char*)algolist->data, algolist->len);
-	TRACE(("algolist add '%*s'", algolist->len, algolist->data))
-	buf_free(algolist);
+	/* Fill out the length */
+	len = buf->pos - startpos - 4;
+	buf_setpos(buf, startpos);
+	buf_putint(buf, len);
+	TRACE(("algolist add %d '%*s'", len, len, buf_getptr(buf, len)))
+	buf_incrwritepos(buf, len);
+}
+
+void buf_put_algolist(buffer * buf, const algo_type localalgos[]) {
+	buf_put_algolist_all(buf, localalgos, 0);
+}
+
+/* returns a list of pointers into algolist, of null-terminated names.
+   ret_list should be passed in with space for *ret_count elements,
+   on return *ret_count has the number of names filled.
+   algolist is modified. */
+static void get_algolist(char* algolist, unsigned int algolist_len,
+				const char* *ret_list, unsigned int *ret_count) {
+	unsigned int max_count = *ret_count;
+	unsigned int i;
+
+	if (*ret_count == 0) {
+		return;
+	}
+	if (algolist_len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
+		*ret_count = 0;
+	}
+
+	/* ret_list will contain a list of the strings parsed out.
+	   We will have at least one string (even if it's just "") */
+	ret_list[0] = algolist;
+	*ret_count = 1;
+	for (i = 0; i < algolist_len; i++) {
+		if (algolist[i] == '\0') {
+			/* someone is trying something strange */
+			*ret_count = 0;
+			return;
+		}
+
+		if (algolist[i] == ',') {
+			if (*ret_count >= max_count) {
+				dropbear_exit("Too many remote algorithms");
+				*ret_count = 0;
+				return;
+			}
+			algolist[i] = '\0';
+			ret_list[*ret_count] = &algolist[i+1];
+			(*ret_count)++;
+		}
+	}
+}
+
+/* Return DROPBEAR_SUCCESS if the namelist contains algo,
+DROPBEAR_FAILURE otherwise. buf position is not incremented. */
+int buf_has_algo(buffer *buf, const char *algo) {
+	unsigned char* algolist = NULL;
+	unsigned int orig_pos = buf->pos;
+	unsigned int len, remotecount, i;
+	const char *remotenames[MAX_PROPOSED_ALGO];
+	int ret = DROPBEAR_FAILURE;
+
+	algolist = buf_getstring(buf, &len);
+	remotecount = MAX_PROPOSED_ALGO;
+	get_algolist(algolist, len, remotenames, &remotecount);
+	for (i = 0; i < remotecount; i++)
+	{
+		if (strcmp(remotenames[i], algo) == 0) {
+			ret = DROPBEAR_SUCCESS;
+			break;
+		}
+	}
+	if (algolist) {
+		m_free(algolist);
+	}
+	buf_setpos(buf, orig_pos);
+	return ret;
+}
+
+algo_type * first_usable_algo(algo_type algos[]) {
+	int i;
+	for (i = 0; algos[i].name != NULL; i++) {
+		if (algos[i].usable) {
+			return &algos[i];
+		}
+	}
+	return NULL;
 }
 
 /* match the first algorithm in the comma-separated list in buf which is
@@ -354,9 +455,7 @@ void buf_put_algolist(buffer * buf, const algo_type localalgos[]) {
  * 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are
  * guessed correctly */
 algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],
-		enum kexguess2_used *kexguess2, int *goodguess)
-{
-
+		int kexguess2, int *goodguess) {
 	char * algolist = NULL;
 	const char *remotenames[MAX_PROPOSED_ALGO], *localnames[MAX_PROPOSED_ALGO];
 	unsigned int len;
@@ -371,40 +470,8 @@ algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],
 	/* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */
 	algolist = buf_getstring(buf, &len);
 	TRACE(("buf_match_algo: %s", algolist))
-	if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
-		goto out;
-	}
-
-	/* remotenames will contain a list of the strings parsed out */
-	/* We will have at least one string (even if it's just "") */
-	remotenames[0] = algolist;
-	remotecount = 1;
-	for (i = 0; i < len; i++) {
-		if (algolist[i] == '\0') {
-			/* someone is trying something strange */
-			goto out;
-		}
-		if (algolist[i] == ',') {
-			algolist[i] = '\0';
-			remotenames[remotecount] = &algolist[i+1];
-			remotecount++;
-		}
-		if (remotecount >= MAX_PROPOSED_ALGO) {
-			break;
-		}
-	}
-	if (kexguess2 && *kexguess2 == KEXGUESS2_LOOK) {
-		for (i = 0; i < remotecount; i++)
-		{
-			if (strcmp(remotenames[i], KEXGUESS2_ALGO_NAME) == 0) {
-				*kexguess2 = KEXGUESS2_YES;
-				break;
-			}
-		}
-		if (*kexguess2 == KEXGUESS2_LOOK) {
-			*kexguess2 = KEXGUESS2_NO;
-		}
-	}
+	remotecount = MAX_PROPOSED_ALGO;
+	get_algolist(algolist, len, remotenames, &remotecount);
 
 	for (i = 0; localalgos[i].name != NULL; i++) {
 		if (localalgos[i].usable) {
@@ -436,12 +503,11 @@ algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],
 			}
 			if (strcmp(servnames[j], clinames[i]) == 0) {
 				/* set if it was a good guess */
-				if (goodguess && kexguess2) {
-					if (*kexguess2 == KEXGUESS2_YES) {
+				if (goodguess != NULL) {
+					if (kexguess2) {
 						if (i == 0) {
 							*goodguess = 1;
 						}
-
 					} else {
 						if (i == 0 && j == 0) {
 							*goodguess = 1;

common-channel.c

@@ -144,7 +144,6 @@ static struct Channel* newchannel(unsigned int remotechan,
 	newchan->index = i;
 	newchan->sent_close = newchan->recv_close = 0;
 	newchan->sent_eof = newchan->recv_eof = 0;
-	newchan->close_handler_done = 0;
 
 	newchan->remotechan = remotechan;
 	newchan->transwindow = transwindow;
@@ -155,7 +154,6 @@ static struct Channel* newchannel(unsigned int remotechan,
 	newchan->readfd = FD_UNINIT;
 	newchan->errfd = FD_CLOSED; /* this isn't always set to start with */
 	newchan->await_open = 0;
-	newchan->flushing = 0;
 
 	newchan->writebuf = cbuf_new(opts.recv_window);
 	newchan->recvwindow = opts.recv_window;
@@ -285,24 +283,29 @@ static void check_close(struct Channel *channel) {
 				channel->writebuf ? cbuf_getused(channel->writebuf) : 0,
 				channel->extrabuf ? cbuf_getused(channel->extrabuf) : 0))
 
-	if (!channel->flushing 
-		&& !channel->close_handler_done
-		&& channel->type->check_close
-		&& channel->type->check_close(channel))
-	{
-		channel->flushing = 1;
-	}
-	
 	/* if a type-specific check_close is defined we will only exit
 	   once that has been triggered. this is only used for a server "session"
-	   channel, to ensure that the shell has exited (and the exit status 
+	   channel, to ensure that the shell has exited (and the exit status
 	   retrieved) before we close things up. */
-	if (!channel->type->check_close	
-		|| channel->close_handler_done
+	if (!channel->type->check_close
+		|| channel->sent_close
 		|| channel->type->check_close(channel)) {
 		close_allowed = 1;
 	}
 
+	/* In flushing mode we close FDs as soon as pipes are empty.
+	This is used to drain out FDs when the process exits, in the case
+	where the FD doesn't have EOF - "sleep 10&echo hello" case */
+	if (channel->flushing) {
+		if (channel->readfd >= 0 && !fd_read_pending(channel->readfd)) {
+			close_chan_fd(channel, channel->readfd, SHUT_RD);
+		}
+		if (ERRFD_IS_READ(channel)
+			&& channel->errfd >= 0 && !fd_read_pending(channel->errfd)) {
+			close_chan_fd(channel, channel->errfd, SHUT_RD);
+		}
+	}
+
 	if (channel->recv_close && !write_pending(channel) && close_allowed) {
 		if (!channel->sent_close) {
 			TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
@@ -318,22 +321,6 @@ static void check_close(struct Channel *channel) {
 		close_chan_fd(channel, channel->writefd, SHUT_WR);
 	}
 
-	/* Special handling for flushing read data after an exit. We
-	   read regardless of whether the select FD was set,
-	   and if there isn't data available, the channel will get closed. */
-	if (channel->flushing) {
-		TRACE(("might send data, flushing"))
-		if (channel->readfd >= 0 && channel->transwindow > 0) {
-			TRACE(("send data readfd"))
-			send_msg_channel_data(channel, 0);
-		}
-		if (ERRFD_IS_READ(channel) && channel->errfd >= 0 
-			&& channel->transwindow > 0) {
-			TRACE(("send data errfd"))
-			send_msg_channel_data(channel, 1);
-		}
-	}
-
 	/* If we're not going to send any more data, send EOF */
 	if (!channel->sent_eof
 			&& channel->readfd == FD_CLOSED 
@@ -357,8 +344,7 @@ static void check_close(struct Channel *channel) {
  * if so, set up the channel properly. Otherwise, the channel is cleaned up, so
  * it is important that the channel reference isn't used after a call to this
  * function */
-void channel_connect_done(int result, int sock, void* user_data, const char* UNUSED(errstring)) {
-
+void channel_connect_done(int result, int sock, void* user_data, const char* errstring) {
 	struct Channel *channel = user_data;
 
 	TRACE(("enter channel_connect_done"))
@@ -366,6 +352,7 @@ void channel_connect_done(int result, int sock, void* user_data, const char* UNU
 	if (result == DROPBEAR_SUCCESS)
 	{
 		channel->readfd = channel->writefd = sock;
+		channel->bidir_fd = 1;
 		channel->conn_pending = NULL;
 		send_msg_channel_open_confirmation(channel, channel->recvwindow,
 				channel->recvmaxpacket);
@@ -374,9 +361,9 @@ void channel_connect_done(int result, int sock, void* user_data, const char* UNU
 	else
 	{
 		send_msg_channel_open_failure(channel->remotechan,
-				SSH_OPEN_CONNECT_FAILED, "", "");
+				SSH_OPEN_CONNECT_FAILED, errstring, "");
 		remove_channel(channel);
-		TRACE(("leave check_in_progress: fail"))
+		TRACE(("leave check_in_progress: fail. internal errstring: %s", errstring))
 	}
 }
 
@@ -385,10 +372,8 @@ void channel_connect_done(int result, int sock, void* user_data, const char* UNU
 static void send_msg_channel_close(struct Channel *channel) {
 
 	TRACE(("enter send_msg_channel_close %p", (void*)channel))
-	if (channel->type->closehandler 
-			&& !channel->close_handler_done) {
+	if (channel->type->closehandler) {
 		channel->type->closehandler(channel);
-		channel->close_handler_done = 1;
 	}
 	
 	CHECKCLEARTOWRITE();
@@ -661,10 +646,8 @@ static void remove_channel(struct Channel * channel) {
 		m_close(channel->errfd);
 	}
 
-	if (!channel->close_handler_done
-		&& channel->type->closehandler) {
-		channel->type->closehandler(channel);
-		channel->close_handler_done = 1;
+	if (channel->type->cleanup) {
+		channel->type->cleanup(channel);
 	}
 
 	if (channel->conn_pending) {
@@ -690,13 +673,7 @@ void recv_msg_channel_request() {
 
 	TRACE(("enter recv_msg_channel_request %p", (void*)channel))
 
-	if (channel->sent_close) {
-		TRACE(("leave recv_msg_channel_request: already closed channel"))
-		return;
-	}
-
-	if (channel->type->reqhandler 
-			&& !channel->close_handler_done) {
+	if (channel->type->reqhandler) {
 		channel->type->reqhandler(channel);
 	} else {
 		int wantreply;
@@ -791,14 +768,6 @@ static void send_msg_channel_data(struct Channel *channel, int isextended) {
 	channel->transwindow -= len;
 
 	encrypt_packet();
-	
-	/* If we receive less data than we requested when flushing, we've
-	   reached the equivalent of EOF */
-	if (channel->flushing && len < (ssize_t)maxlen)
-	{
-		TRACE(("closing from channel, flushing out."))
-		close_chan_fd(channel, fd, SHUT_RD);
-	}
 	TRACE(("leave send_msg_channel_data"))
 }
 
@@ -1011,6 +980,11 @@ cleanup:
 void send_msg_channel_failure(const struct Channel *channel) {
 
 	TRACE(("enter send_msg_channel_failure"))
+
+	if (channel->sent_close) {
+		TRACE(("Skipping sending msg_channel_failure for closed channel"))
+		return;
+	}
 	CHECKCLEARTOWRITE();
 
 	buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_FAILURE);
@@ -1024,6 +998,10 @@ void send_msg_channel_failure(const struct Channel *channel) {
 void send_msg_channel_success(const struct Channel *channel) {
 
 	TRACE(("enter send_msg_channel_success"))
+	if (channel->sent_close) {
+		TRACE(("Skipping sending msg_channel_success for closed channel"))
+		return;
+	}
 	CHECKCLEARTOWRITE();
 
 	buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_SUCCESS);
@@ -1075,7 +1053,7 @@ static void close_chan_fd(struct Channel *channel, int fd, int how) {
 
 	int closein = 0, closeout = 0;
 
-	if (channel->type->sepfds) {
+	if (channel->bidir_fd) {
 		TRACE(("SHUTDOWN(%d, %d)", fd, how))
 		shutdown(fd, how);
 		if (how == 0) {
@@ -1105,7 +1083,7 @@ static void close_chan_fd(struct Channel *channel, int fd, int how) {
 
 	/* if we called shutdown on it and all references are gone, then we 
 	 * need to close() it to stop it lingering */
-	if (channel->type->sepfds && channel->readfd == FD_CLOSED 
+	if (channel->bidir_fd && channel->readfd == FD_CLOSED 
 		&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
 		TRACE(("CLOSE (finally) of %d", fd))
 		m_close(fd);
@@ -1138,6 +1116,7 @@ int send_msg_channel_open_init(int fd, const struct ChanType *type) {
 
 	chan->writefd = chan->readfd = fd;
 	ses.maxfd = MAX(ses.maxfd, fd);
+	chan->bidir_fd = 1;
 
 	chan->await_open = 1;
 
@@ -1154,7 +1133,7 @@ int send_msg_channel_open_init(int fd, const struct ChanType *type) {
 	return DROPBEAR_SUCCESS;
 }
 
-/* Confirmation that our channel open request (for forwardings) was 
+/* Confirmation that our channel open request was 
  * successful*/
 void recv_msg_channel_open_confirmation() {
 

common-kex.c

@@ -36,6 +36,7 @@
 #include "dbrandom.h"
 #include "runopts.h"
 #include "ecc.h"
+#include "curve25519.h"
 #include "crypto_desc.h"
 
 static void kexinitialise(void);
@@ -48,7 +49,6 @@ static void read_kex_algos(void);
 /* helper function for gen_new_keys */
 static void hashkeys(unsigned char *out, unsigned int outlen, 
 		const hash_state * hs, const unsigned char X);
-static void finish_kexhashbuf(void);
 
 
 /* Send our list of algorithms we can use */
@@ -65,7 +65,7 @@ void send_msg_kexinit() {
 	buf_put_algolist(ses.writepayload, sshkex);
 
 	/* server_host_key_algorithms */
-	buf_put_algolist(ses.writepayload, sshhostkey);
+	buf_put_algolist(ses.writepayload, sigalgs);
 
 	/* encryption_algorithms_client_to_server */
 	buf_put_algolist(ses.writepayload, sshciphers);
@@ -110,8 +110,9 @@ void send_msg_kexinit() {
 	ses.newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
 
 	if (ses.send_kex_first_guess) {
-		ses.newkeys->algo_kex = sshkex[0].data;
-		ses.newkeys->algo_hostkey = sshhostkey[0].val;
+		ses.newkeys->algo_kex = first_usable_algo(sshkex)->data;
+		ses.newkeys->algo_signature = first_usable_algo(sigalgs)->val;
+		ses.newkeys->algo_hostkey = signkey_type_from_signature(ses.newkeys->algo_signature);
 		ses.send_kex_first_guess();
 	}
 
@@ -152,6 +153,7 @@ static void switch_keys() {
 		TRACE(("switch_keys done"))
 		ses.keys->algo_kex = ses.newkeys->algo_kex;
 		ses.keys->algo_hostkey = ses.newkeys->algo_hostkey;
+		ses.keys->algo_signature = ses.newkeys->algo_signature;
 		ses.keys->allow_compress = 0;
 		m_free(ses.newkeys);
 		ses.newkeys = NULL;
@@ -173,6 +175,9 @@ void send_msg_newkeys() {
 	
 	/* set up our state */
 	ses.kexstate.sentnewkeys = 1;
+	if (ses.kexstate.donefirstkex) {
+		ses.kexstate.donesecondkex = 1;
+	}
 	ses.kexstate.donefirstkex = 1;
 	ses.dataallowed = 1; /* we can send other packets again now */
 	gen_new_keys();
@@ -195,8 +200,6 @@ void recv_msg_newkeys() {
 
 /* Set up the kex for the first time */
 void kexfirstinitialise() {
-	ses.kexstate.donefirstkex = 0;
-
 #ifdef DISABLE_ZLIB
 	ses.compress_algos = ssh_nocompress;
 #else
@@ -329,9 +332,13 @@ static void gen_new_keys() {
 	hashkeys(S2C_key, sizeof(S2C_key), &hs, 'D');
 
 	if (ses.newkeys->recv.algo_crypt->cipherdesc != NULL) {
-		int recv_cipher = find_cipher(ses.newkeys->recv.algo_crypt->cipherdesc->name);
-		if (recv_cipher < 0)
-			dropbear_exit("Crypto error");
+		int recv_cipher = -1;
+		if (ses.newkeys->recv.algo_crypt->cipherdesc->name != NULL) {
+			recv_cipher = find_cipher(ses.newkeys->recv.algo_crypt->cipherdesc->name);
+			if (recv_cipher < 0) {
+				dropbear_exit("Crypto error");
+			}
+		}
 		if (ses.newkeys->recv.crypt_mode->start(recv_cipher, 
 				recv_IV, recv_key, 
 				ses.newkeys->recv.algo_crypt->keysize, 0, 
@@ -341,9 +348,13 @@ static void gen_new_keys() {
 	}
 
 	if (ses.newkeys->trans.algo_crypt->cipherdesc != NULL) {
-		int trans_cipher = find_cipher(ses.newkeys->trans.algo_crypt->cipherdesc->name);
-		if (trans_cipher < 0)
-			dropbear_exit("Crypto error");
+		int trans_cipher = -1;
+		if (ses.newkeys->trans.algo_crypt->cipherdesc->name != NULL) {
+			trans_cipher = find_cipher(ses.newkeys->trans.algo_crypt->cipherdesc->name);
+			if (trans_cipher < 0) {
+				dropbear_exit("Crypto error");
+			}
+		}
 		if (ses.newkeys->trans.crypt_mode->start(trans_cipher, 
 				trans_IV, trans_key, 
 				ses.newkeys->trans.algo_crypt->keysize, 0, 
@@ -391,6 +402,14 @@ int is_compress_recv() {
 			&& ses.keys->recv.algo_comp == DROPBEAR_COMP_ZLIB_DELAY);
 }
 
+static void* dropbear_zalloc(void* UNUSED(opaque), uInt items, uInt size) {
+	return m_calloc(items, size);
+}
+
+static void dropbear_zfree(void* UNUSED(opaque), void* ptr) {
+	m_free(ptr);
+}
+
 /* Set up new zlib compression streams, close the old ones. Only
  * called from gen_new_keys() */
 static void gen_new_zstream_recv() {
@@ -399,8 +418,8 @@ static void gen_new_zstream_recv() {
 	if (ses.newkeys->recv.algo_comp == DROPBEAR_COMP_ZLIB
 			|| ses.newkeys->recv.algo_comp == DROPBEAR_COMP_ZLIB_DELAY) {
 		ses.newkeys->recv.zstream = (z_streamp)m_malloc(sizeof(z_stream));
-		ses.newkeys->recv.zstream->zalloc = Z_NULL;
-		ses.newkeys->recv.zstream->zfree = Z_NULL;
+		ses.newkeys->recv.zstream->zalloc = dropbear_zalloc;
+		ses.newkeys->recv.zstream->zfree = dropbear_zfree;
 		
 		if (inflateInit(ses.newkeys->recv.zstream) != Z_OK) {
 			dropbear_exit("zlib error");
@@ -423,8 +442,8 @@ static void gen_new_zstream_trans() {
 	if (ses.newkeys->trans.algo_comp == DROPBEAR_COMP_ZLIB
 			|| ses.newkeys->trans.algo_comp == DROPBEAR_COMP_ZLIB_DELAY) {
 		ses.newkeys->trans.zstream = (z_streamp)m_malloc(sizeof(z_stream));
-		ses.newkeys->trans.zstream->zalloc = Z_NULL;
-		ses.newkeys->trans.zstream->zfree = Z_NULL;
+		ses.newkeys->trans.zstream->zalloc = dropbear_zalloc;
+		ses.newkeys->trans.zstream->zfree = dropbear_zfree;
 	
 		if (deflateInit2(ses.newkeys->trans.zstream, Z_DEFAULT_COMPRESSION,
 					Z_DEFLATED, DROPBEAR_ZLIB_WINDOW_BITS, 
@@ -468,6 +487,12 @@ void recv_msg_kexinit() {
 		TRACE(("continue recv_msg_kexinit: sent kexinit"))
 	}
 
+	/* "Once a party has sent a SSH_MSG_KEXINIT message ...
+	further SSH_MSG_KEXINIT messages MUST NOT be sent" */
+	if (ses.kexstate.recvkexinit) {
+		dropbear_exit("Unexpected KEXINIT");
+	}
+
 	/* start the kex hash */
 	local_ident_len = strlen(LOCAL_IDENT);
 	remote_ident_len = strlen(ses.remoteident);
@@ -529,6 +554,7 @@ void recv_msg_kexinit() {
 	TRACE(("leave recv_msg_kexinit"))
 }
 
+#if DROPBEAR_NORMAL_DH
 static void load_dh_p(mp_int * dh_p)
 {
 	bytes_to_mp(dh_p, ses.newkeys->algo_kex->dh_p_bytes, 
@@ -553,9 +579,7 @@ struct kex_dh_param *gen_kexdh_param() {
 	/* read the prime and generator*/
 	load_dh_p(&dh_p);
 	
-	if (mp_set_int(&dh_g, DH_G_VAL) != MP_OKAY) {
-		dropbear_exit("Diffie-Hellman error");
-	}
+	mp_set_ul(&dh_g, DH_G_VAL);
 
 	/* calculate q = (p-1)/2 */
 	/* dh_priv is just a temp var here */
@@ -639,6 +663,7 @@ void kexdh_comb_key(struct kex_dh_param *param, mp_int *dh_pub_them,
 	/* calculate the hash H to sign */
 	finish_kexhashbuf();
 }
+#endif
 
 #if DROPBEAR_ECDH
 struct kex_ecdh_param *gen_kexecdh_param() {
@@ -687,29 +712,27 @@ void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them,
 	/* K, the shared secret */
 	buf_putmpint(ses.kexhashbuf, ses.dh_K);
 
+	ecc_free(Q_them);
+	m_free(Q_them);
+
 	/* calculate the hash H to sign */
 	finish_kexhashbuf();
 }
 #endif /* DROPBEAR_ECDH */
 
 #if DROPBEAR_CURVE25519
-struct kex_curve25519_param *gen_kexcurve25519_param () {
+struct kex_curve25519_param *gen_kexcurve25519_param() {
 	/* Per http://cr.yp.to/ecdh.html */
 	struct kex_curve25519_param *param = m_malloc(sizeof(*param));
 	const unsigned char basepoint[32] = {9};
 
 	genrandom(param->priv, CURVE25519_LEN);
-	param->priv[0] &= 248;
-	param->priv[31] &= 127;
-	param->priv[31] |= 64;
-
-	curve25519_donna(param->pub, param->priv, basepoint);
+	dropbear_curve25519_scalarmult(param->pub, param->priv, basepoint);
 
 	return param;
 }
 
-void free_kexcurve25519_param(struct kex_curve25519_param *param)
-{
+void free_kexcurve25519_param(struct kex_curve25519_param *param) {
 	m_burn(param->priv, CURVE25519_LEN);
 	m_free(param);
 }
@@ -726,7 +749,7 @@ void kexcurve25519_comb_key(const struct kex_curve25519_param *param, const buff
 		dropbear_exit("Bad curve25519");
 	}
 
-	curve25519_donna(out, param->priv, buf_pub_them->data);
+	dropbear_curve25519_scalarmult(out, param->priv, buf_pub_them->data);
 
 	if (constant_time_memcmp(zeroes, out, CURVE25519_LEN) == 0) {
 		dropbear_exit("Bad curve25519");
@@ -761,8 +784,7 @@ void kexcurve25519_comb_key(const struct kex_curve25519_param *param, const buff
 #endif /* DROPBEAR_CURVE25519 */
 
 
-
-static void finish_kexhashbuf(void) {
+void finish_kexhashbuf(void) {
 	hash_state hs;
 	const struct ltc_hash_descriptor *hash_desc = ses.newkeys->algo_kex->hash_desc;
 
@@ -813,21 +835,36 @@ static void read_kex_algos() {
 	int goodguess = 0;
 	int allgood = 1; /* we AND this with each goodguess and see if its still
 						true after */
-
-#if DROPBEAR_KEXGUESS2
-	enum kexguess2_used kexguess2 = KEXGUESS2_LOOK;
-#else
-	enum kexguess2_used kexguess2 = KEXGUESS2_NO;
-#endif
+	int kexguess2 = 0;
 
 	buf_incrpos(ses.payload, 16); /* start after the cookie */
 
 	memset(ses.newkeys, 0x0, sizeof(*ses.newkeys));
 
 	/* kex_algorithms */
-	algo = buf_match_algo(ses.payload, sshkex, &kexguess2, &goodguess);
+#if DROPBEAR_KEXGUESS2
+	if (buf_has_algo(ses.payload, KEXGUESS2_ALGO_NAME) == DROPBEAR_SUCCESS) {
+		kexguess2 = 1;
+	}
+#endif
+
+#if DROPBEAR_EXT_INFO
+	/* Determine if SSH_MSG_EXT_INFO messages should be sent.
+	Should be done for the first key exchange. Only required on server side
+    for server-sig-algs */
+	if (IS_DROPBEAR_SERVER) {
+		if (!ses.kexstate.donefirstkex) {
+			if (buf_has_algo(ses.payload, SSH_EXT_INFO_C) == DROPBEAR_SUCCESS) {
+				ses.allow_ext_info = 1;
+			}
+		}
+	}
+#endif
+
+	algo = buf_match_algo(ses.payload, sshkex, kexguess2, &goodguess);
 	allgood &= goodguess;
-	if (algo == NULL || algo->val == KEXGUESS2_ALGO_ID) {
+	if (algo == NULL || algo->data == NULL) {
+		/* kexguess2, ext-info-c, ext-info-s should not match negotiation */
 		erralgo = "kex";
 		goto error;
 	}
@@ -836,17 +873,18 @@ static void read_kex_algos() {
 	ses.newkeys->algo_kex = algo->data;
 
 	/* server_host_key_algorithms */
-	algo = buf_match_algo(ses.payload, sshhostkey, &kexguess2, &goodguess);
+	algo = buf_match_algo(ses.payload, sigalgs, kexguess2, &goodguess);
 	allgood &= goodguess;
 	if (algo == NULL) {
 		erralgo = "hostkey";
 		goto error;
 	}
-	TRACE(("hostkey algo %s", algo->name))
-	ses.newkeys->algo_hostkey = algo->val;
+	TRACE(("signature algo %s", algo->name))
+	ses.newkeys->algo_signature = algo->val;
+	ses.newkeys->algo_hostkey = signkey_type_from_signature(ses.newkeys->algo_signature);
 
 	/* encryption_algorithms_client_to_server */
-	c2s_cipher_algo = buf_match_algo(ses.payload, sshciphers, NULL, NULL);
+	c2s_cipher_algo = buf_match_algo(ses.payload, sshciphers, 0, NULL);
 	if (c2s_cipher_algo == NULL) {
 		erralgo = "enc c->s";
 		goto error;
@@ -854,7 +892,7 @@ static void read_kex_algos() {
 	TRACE(("enc c2s is  %s", c2s_cipher_algo->name))
 
 	/* encryption_algorithms_server_to_client */
-	s2c_cipher_algo = buf_match_algo(ses.payload, sshciphers, NULL, NULL);
+	s2c_cipher_algo = buf_match_algo(ses.payload, sshciphers, 0, NULL);
 	if (s2c_cipher_algo == NULL) {
 		erralgo = "enc s->c";
 		goto error;
@@ -862,23 +900,33 @@ static void read_kex_algos() {
 	TRACE(("enc s2c is  %s", s2c_cipher_algo->name))
 
 	/* mac_algorithms_client_to_server */
-	c2s_hash_algo = buf_match_algo(ses.payload, sshhashes, NULL, NULL);
+	c2s_hash_algo = buf_match_algo(ses.payload, sshhashes, 0, NULL);
+#if DROPBEAR_AEAD_MODE
+	if (((struct dropbear_cipher_mode*)c2s_cipher_algo->mode)->aead_crypt != NULL) {
+		c2s_hash_algo = NULL;
+	} else
+#endif
 	if (c2s_hash_algo == NULL) {
 		erralgo = "mac c->s";
 		goto error;
 	}
-	TRACE(("hash c2s is  %s", c2s_hash_algo->name))
+	TRACE(("hash c2s is  %s", c2s_hash_algo ? c2s_hash_algo->name : "<implicit>"))
 
 	/* mac_algorithms_server_to_client */
-	s2c_hash_algo = buf_match_algo(ses.payload, sshhashes, NULL, NULL);
+	s2c_hash_algo = buf_match_algo(ses.payload, sshhashes, 0, NULL);
+#if DROPBEAR_AEAD_MODE
+	if (((struct dropbear_cipher_mode*)s2c_cipher_algo->mode)->aead_crypt != NULL) {
+		s2c_hash_algo = NULL;
+	} else
+#endif
 	if (s2c_hash_algo == NULL) {
 		erralgo = "mac s->c";
 		goto error;
 	}
-	TRACE(("hash s2c is  %s", s2c_hash_algo->name))
+	TRACE(("hash s2c is  %s", s2c_hash_algo ? s2c_hash_algo->name : "<implicit>"))
 
 	/* compression_algorithms_client_to_server */
-	c2s_comp_algo = buf_match_algo(ses.payload, ses.compress_algos, NULL, NULL);
+	c2s_comp_algo = buf_match_algo(ses.payload, ses.compress_algos, 0, NULL);
 	if (c2s_comp_algo == NULL) {
 		erralgo = "comp c->s";
 		goto error;
@@ -886,7 +934,7 @@ static void read_kex_algos() {
 	TRACE(("hash c2s is  %s", c2s_comp_algo->name))
 
 	/* compression_algorithms_server_to_client */
-	s2c_comp_algo = buf_match_algo(ses.payload, ses.compress_algos, NULL, NULL);
+	s2c_comp_algo = buf_match_algo(ses.payload, ses.compress_algos, 0, NULL);
 	if (s2c_comp_algo == NULL) {
 		erralgo = "comp s->c";
 		goto error;
@@ -920,8 +968,14 @@ static void read_kex_algos() {
 		ses.newkeys->trans.crypt_mode =
 			(struct dropbear_cipher_mode*)c2s_cipher_algo->mode;
 		ses.newkeys->recv.algo_mac = 
+#if DROPBEAR_AEAD_MODE
+			s2c_hash_algo == NULL ? ses.newkeys->recv.crypt_mode->aead_mac :
+#endif
 			(struct dropbear_hash*)s2c_hash_algo->data;
 		ses.newkeys->trans.algo_mac = 
+#if DROPBEAR_AEAD_MODE
+			c2s_hash_algo == NULL ? ses.newkeys->trans.crypt_mode->aead_mac :
+#endif
 			(struct dropbear_hash*)c2s_hash_algo->data;
 		ses.newkeys->recv.algo_comp = s2c_comp_algo->val;
 		ses.newkeys->trans.algo_comp = c2s_comp_algo->val;
@@ -936,13 +990,25 @@ static void read_kex_algos() {
 		ses.newkeys->trans.crypt_mode =
 			(struct dropbear_cipher_mode*)s2c_cipher_algo->mode;
 		ses.newkeys->recv.algo_mac = 
+#if DROPBEAR_AEAD_MODE
+			c2s_hash_algo == NULL ? ses.newkeys->recv.crypt_mode->aead_mac :
+#endif
 			(struct dropbear_hash*)c2s_hash_algo->data;
 		ses.newkeys->trans.algo_mac = 
+#if DROPBEAR_AEAD_MODE
+			s2c_hash_algo == NULL ? ses.newkeys->trans.crypt_mode->aead_mac :
+#endif
 			(struct dropbear_hash*)s2c_hash_algo->data;
 		ses.newkeys->recv.algo_comp = c2s_comp_algo->val;
 		ses.newkeys->trans.algo_comp = s2c_comp_algo->val;
 	}
 
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		fuzz_kex_fakealgos();
+	}
+#endif
+
 	/* reserved for future extensions */
 	buf_getint(ses.payload);
 

common-runopts.c

@@ -64,45 +64,36 @@ out:
 
 #if DROPBEAR_USER_ALGO_LIST
 void
-parse_ciphers_macs()
-{
-	if (opts.cipher_list)
-	{
-		if (strcmp(opts.cipher_list, "help") == 0)
-		{
+parse_ciphers_macs() {
+	int printed_help = 0;
+	if (opts.cipher_list) {
+		if (strcmp(opts.cipher_list, "help") == 0) {
 			char *ciphers = algolist_string(sshciphers);
-			dropbear_log(LOG_INFO, "Available ciphers:\n%s\n", ciphers);
+			dropbear_log(LOG_INFO, "Available ciphers: %s", ciphers);
 			m_free(ciphers);
-			dropbear_exit(".");
-		}
-
-		if (strcmp(opts.cipher_list, "none") == 0)
-		{
-			/* Encryption is required during authentication */
-			opts.cipher_list = "none,aes128-ctr";
-		}
-
-		if (check_user_algos(opts.cipher_list, sshciphers, "cipher") == 0)
-		{
-			dropbear_exit("No valid ciphers specified for '-c'");
+			printed_help = 1;
+		} else {
+			if (check_user_algos(opts.cipher_list, sshciphers, "cipher") == 0) {
+				dropbear_exit("No valid ciphers specified for '-c'");
+			}
 		}
 	}
 
-	if (opts.mac_list)
-	{
-		if (strcmp(opts.mac_list, "help") == 0)
-		{
+	if (opts.mac_list) {
+		if (strcmp(opts.mac_list, "help") == 0) {
 			char *macs = algolist_string(sshhashes);
-			dropbear_log(LOG_INFO, "Available MACs:\n%s\n", macs);
+			dropbear_log(LOG_INFO, "Available MACs: %s", macs);
 			m_free(macs);
-			dropbear_exit(".");
-		}
-
-		if (check_user_algos(opts.mac_list, sshhashes, "MAC") == 0)
-		{
-			dropbear_exit("No valid MACs specified for '-m'");
+			printed_help = 1;
+		} else {
+			if (check_user_algos(opts.mac_list, sshhashes, "MAC") == 0) {
+				dropbear_exit("No valid MACs specified for '-m'");
+			}
 		}
 	}
+	if (printed_help) {
+		dropbear_exit(".");
+	}
 }
 #endif
 
@@ -110,4 +101,20 @@ void print_version() {
 	fprintf(stderr, "Dropbear v%s\n", DROPBEAR_VERSION);
 }
 
+void parse_recv_window(const char* recv_window_arg) {
+	int ret;
+	unsigned int rw;
+
+	ret = m_str_to_uint(recv_window_arg, &rw);
+	if (ret == DROPBEAR_FAILURE || rw == 0 || rw > MAX_RECV_WINDOW) {
+		if (rw > MAX_RECV_WINDOW) {
+			opts.recv_window = MAX_RECV_WINDOW;
+		}
+		dropbear_log(LOG_WARNING, "Bad recv window '%s', using %d",
+			recv_window_arg, opts.recv_window);
+	} else {
+		opts.recv_window = rw;
+	}
+
+}
 

common-session.c

@@ -68,6 +68,16 @@ void common_session_init(int sock_in, int sock_out) {
 	/* Sets it to lowdelay */
 	update_channel_prio();
 
+#if !DROPBEAR_SVR_MULTIUSER
+	/* A sanity check to prevent an accidental configuration option
+	   leaving multiuser systems exposed */
+	errno = 0;
+	getuid();
+	if (errno != ENOSYS) {
+		dropbear_exit("Non-multiuser Dropbear requires a non-multiuser kernel");
+	}
+#endif
+
 	now = monotonic_now();
 	ses.connect_time = now;
 	ses.last_packet_time_keepalive_recv = now;
@@ -75,14 +85,18 @@ void common_session_init(int sock_in, int sock_out) {
 	ses.last_packet_time_any_sent = 0;
 	ses.last_packet_time_keepalive_sent = 0;
 	
+#if DROPBEAR_FUZZ
+	if (!fuzz.fuzzing)
+#endif
+	{
 	if (pipe(ses.signal_pipe) < 0) {
 		dropbear_exit("Signal pipe failed");
 	}
 	setnonblocking(ses.signal_pipe[0]);
 	setnonblocking(ses.signal_pipe[1]);
-
 	ses.maxfd = MAX(ses.maxfd, ses.signal_pipe[0]);
 	ses.maxfd = MAX(ses.maxfd, ses.signal_pipe[1]);
+	}
 	
 	ses.writepayload = buf_new(TRANS_MAX_PAYLOAD_LEN);
 	ses.transseq = 0;
@@ -133,6 +147,10 @@ void common_session_init(int sock_in, int sock_out) {
 
 	ses.allowprivport = 0;
 
+#if DROPBEAR_PLUGIN
+        ses.plugin_session = NULL;
+#endif
+
 	TRACE(("leave session_init"))
 }
 
@@ -148,13 +166,19 @@ void session_loop(void(*loophandler)(void)) {
 
 		timeout.tv_sec = select_timeout();
 		timeout.tv_usec = 0;
-		FD_ZERO(&writefd);
-		FD_ZERO(&readfd);
+		DROPBEAR_FD_ZERO(&writefd);
+		DROPBEAR_FD_ZERO(&readfd);
+
 		dropbear_assert(ses.payload == NULL);
 
 		/* We get woken up when signal handlers write to this pipe.
 		   SIGCHLD in svr-chansession is the only one currently. */
+#if DROPBEAR_FUZZ
+		if (!fuzz.fuzzing) 
+#endif
+		{
 		FD_SET(ses.signal_pipe[0], &readfd);
+		}
 
 		/* set up for channels which can be read/written */
 		setchannelfds(&readfd, &writefd, writequeue_has_space);
@@ -195,8 +219,8 @@ void session_loop(void(*loophandler)(void)) {
 			 * want to iterate over channels etc for reading, to handle
 			 * server processes exiting etc. 
 			 * We don't want to read/write FDs. */
-			FD_ZERO(&writefd);
-			FD_ZERO(&readfd);
+			DROPBEAR_FD_ZERO(&writefd);
+			DROPBEAR_FD_ZERO(&readfd);
 		}
 		
 		/* We'll just empty out the pipe if required. We don't do
@@ -298,6 +322,16 @@ void session_cleanup() {
 		buf_free(dequeue(&ses.writequeue));
 	}
 
+	m_free(ses.newkeys);
+#ifndef DISABLE_ZLIB
+	if (ses.keys->recv.zstream != NULL) {
+		if (inflateEnd(ses.keys->recv.zstream) == Z_STREAM_ERROR) {
+			dropbear_exit("Crypto error");
+		}
+		m_free(ses.keys->recv.zstream);
+	}
+#endif
+
 	m_free(ses.remoteident);
 	m_free(ses.authstate.pw_dir);
 	m_free(ses.authstate.pw_name);
@@ -327,7 +361,7 @@ void session_cleanup() {
 void send_session_identification() {
 	buffer *writebuf = buf_new(strlen(LOCAL_IDENT "\r\n") + 1);
 	buf_putbytes(writebuf, (const unsigned char *) LOCAL_IDENT "\r\n", strlen(LOCAL_IDENT "\r\n"));
-	writebuf_enqueue(writebuf, 0);
+	writebuf_enqueue(writebuf);
 }
 
 static void read_session_identification() {
@@ -336,8 +370,11 @@ static void read_session_identification() {
 	int len = 0;
 	char done = 0;
 	int i;
-	/* If they send more than 50 lines, something is wrong */
-	for (i = 0; i < 50; i++) {
+
+	/* Servers may send other lines of data before sending the
+	 * version string, client must be able to process such lines.
+	 * If they send more than 50 lines, something is wrong */
+	for (i = IS_DROPBEAR_CLIENT ? 50 : 1; i > 0; i--) {
 		len = ident_readln(ses.sock_in, linebuf, sizeof(linebuf));
 
 		if (len < 0 && errno != EINTR) {
@@ -387,7 +424,7 @@ static int ident_readln(int fd, char* buf, int count) {
 		return -1;
 	}
 
-	FD_ZERO(&fds);
+	DROPBEAR_FD_ZERO(&fds);
 
 	/* select since it's a non-blocking fd */
 	
@@ -428,6 +465,11 @@ static int ident_readln(int fd, char* buf, int count) {
 				TRACE(("leave ident_readln: EOF"))
 				return -1;
 			}
+
+#if DROPBEAR_FUZZ
+			fuzz_dump(&in, 1);
+#endif
+
 			if (in == '\n') {
 				/* end of ident string */
 				break;

config.h.in

@@ -0,0 +1,453 @@
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Using AIX */
+#undef AIX
+
+/* Broken getaddrinfo */
+#undef BROKEN_GETADDRINFO
+
+/* Use bundled libtom */
+#undef BUNDLED_LIBTOM
+
+/* lastlog file location */
+#undef CONF_LASTLOG_FILE
+
+/* utmpx file location */
+#undef CONF_UTMPX_FILE
+
+/* utmp file location */
+#undef CONF_UTMP_FILE
+
+/* wtmpx file location */
+#undef CONF_WTMPX_FILE
+
+/* wtmp file location */
+#undef CONF_WTMP_FILE
+
+/* Disable use of lastlog() */
+#undef DISABLE_LASTLOG
+
+/* Use PAM */
+#undef DISABLE_PAM
+
+/* Disable use of pututline() */
+#undef DISABLE_PUTUTLINE
+
+/* Disable use of pututxline() */
+#undef DISABLE_PUTUTXLINE
+
+/* Using syslog */
+#undef DISABLE_SYSLOG
+
+/* Disable use of utmp */
+#undef DISABLE_UTMP
+
+/* Disable use of utmpx */
+#undef DISABLE_UTMPX
+
+/* Disable use of wtmp */
+#undef DISABLE_WTMP
+
+/* Disable use of wtmpx */
+#undef DISABLE_WTMPX
+
+/* Use zlib */
+#undef DISABLE_ZLIB
+
+/* Fuzzing */
+#undef DROPBEAR_FUZZ
+
+/* External Public Key Authentication */
+#undef DROPBEAR_PLUGIN
+
+/* Define to 1 if you have the `basename' function. */
+#undef HAVE_BASENAME
+
+/* Define to 1 if you have the `clearenv' function. */
+#undef HAVE_CLEARENV
+
+/* Define to 1 if you have the `clock_gettime' function. */
+#undef HAVE_CLOCK_GETTIME
+
+/* Define if gai_strerror() returns const char * */
+#undef HAVE_CONST_GAI_STRERROR_PROTO
+
+/* crypt() function */
+#undef HAVE_CRYPT
+
+/* Define to 1 if you have the <crypt.h> header file. */
+#undef HAVE_CRYPT_H
+
+/* Define to 1 if you have the `daemon' function. */
+#undef HAVE_DAEMON
+
+/* Use /dev/ptc & /dev/pts */
+#undef HAVE_DEV_PTS_AND_PTC
+
+/* Define to 1 if you have the `endutent' function. */
+#undef HAVE_ENDUTENT
+
+/* Define to 1 if you have the `endutxent' function. */
+#undef HAVE_ENDUTXENT
+
+/* Define to 1 if you have the `explicit_bzero' function. */
+#undef HAVE_EXPLICIT_BZERO
+
+/* Define to 1 if you have the `fork' function. */
+#undef HAVE_FORK
+
+/* Define to 1 if you have the `freeaddrinfo' function. */
+#undef HAVE_FREEADDRINFO
+
+/* Define to 1 if you have the `gai_strerror' function. */
+#undef HAVE_GAI_STRERROR
+
+/* Define to 1 if you have the `getaddrinfo' function. */
+#undef HAVE_GETADDRINFO
+
+/* Define to 1 if you have the `getgrouplist' function. */
+#undef HAVE_GETGROUPLIST
+
+/* Define to 1 if you have the `getnameinfo' function. */
+#undef HAVE_GETNAMEINFO
+
+/* Define to 1 if you have the `getpass' function. */
+#undef HAVE_GETPASS
+
+/* Define to 1 if you have the `getrandom' function. */
+#undef HAVE_GETRANDOM
+
+/* Define to 1 if you have the `getspnam' function. */
+#undef HAVE_GETSPNAM
+
+/* Define to 1 if you have the `getusershell' function. */
+#undef HAVE_GETUSERSHELL
+
+/* Define to 1 if you have the `getutent' function. */
+#undef HAVE_GETUTENT
+
+/* Define to 1 if you have the `getutid' function. */
+#undef HAVE_GETUTID
+
+/* Define to 1 if you have the `getutline' function. */
+#undef HAVE_GETUTLINE
+
+/* Define to 1 if you have the `getutxent' function. */
+#undef HAVE_GETUTXENT
+
+/* Define to 1 if you have the `getutxid' function. */
+#undef HAVE_GETUTXID
+
+/* Define to 1 if you have the `getutxline' function. */
+#undef HAVE_GETUTXLINE
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the <lastlog.h> header file. */
+#undef HAVE_LASTLOG_H
+
+/* Define to 1 if you have the <libgen.h> header file. */
+#undef HAVE_LIBGEN_H
+
+/* Define to 1 if you have the `pam' library (-lpam). */
+#undef HAVE_LIBPAM
+
+/* Define to 1 if you have the <libutil.h> header file. */
+#undef HAVE_LIBUTIL_H
+
+/* Define to 1 if you have the `z' library (-lz). */
+#undef HAVE_LIBZ
+
+/* Define to 1 if you have the <linux/pkt_sched.h> header file. */
+#undef HAVE_LINUX_PKT_SCHED_H
+
+/* Have login() function */
+#undef HAVE_LOGIN
+
+/* Define to 1 if you have the `logout' function. */
+#undef HAVE_LOGOUT
+
+/* Define to 1 if you have the `logwtmp' function. */
+#undef HAVE_LOGWTMP
+
+/* Define to 1 if you have the `mach_absolute_time' function. */
+#undef HAVE_MACH_ABSOLUTE_TIME
+
+/* Define to 1 if you have the <mach/mach_time.h> header file. */
+#undef HAVE_MACH_MACH_TIME_H
+
+/* Define to 1 if you have the <memory.h> header file. */
+#undef HAVE_MEMORY_H
+
+/* Define to 1 if you have the `memset_s' function. */
+#undef HAVE_MEMSET_S
+
+/* Define to 1 if you have the <netdb.h> header file. */
+#undef HAVE_NETDB_H
+
+/* Define to 1 if you have the <netinet/in.h> header file. */
+#undef HAVE_NETINET_IN_H
+
+/* Define to 1 if you have the <netinet/in_systm.h> header file. */
+#undef HAVE_NETINET_IN_SYSTM_H
+
+/* Define to 1 if you have the <netinet/tcp.h> header file. */
+#undef HAVE_NETINET_TCP_H
+
+/* Have openpty() function */
+#undef HAVE_OPENPTY
+
+/* Define to 1 if you have the `pam_fail_delay' function. */
+#undef HAVE_PAM_FAIL_DELAY
+
+/* Define to 1 if you have the <pam/pam_appl.h> header file. */
+#undef HAVE_PAM_PAM_APPL_H
+
+/* Define to 1 if you have the <paths.h> header file. */
+#undef HAVE_PATHS_H
+
+/* Define to 1 if you have the <pty.h> header file. */
+#undef HAVE_PTY_H
+
+/* Define to 1 if you have the `putenv' function. */
+#undef HAVE_PUTENV
+
+/* Define to 1 if you have the `pututline' function. */
+#undef HAVE_PUTUTLINE
+
+/* Define to 1 if you have the `pututxline' function. */
+#undef HAVE_PUTUTXLINE
+
+/* Define to 1 if you have the <security/pam_appl.h> header file. */
+#undef HAVE_SECURITY_PAM_APPL_H
+
+/* Define to 1 if you have the `setutent' function. */
+#undef HAVE_SETUTENT
+
+/* Define to 1 if you have the `setutxent' function. */
+#undef HAVE_SETUTXENT
+
+/* Define to 1 if you have the <shadow.h> header file. */
+#undef HAVE_SHADOW_H
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the `strlcat' function. */
+#undef HAVE_STRLCAT
+
+/* Define to 1 if you have the `strlcpy' function. */
+#undef HAVE_STRLCPY
+
+/* Define to 1 if you have the <stropts.h> header file. */
+#undef HAVE_STROPTS_H
+
+/* Have struct addrinfo */
+#undef HAVE_STRUCT_ADDRINFO
+
+/* Have struct in6_addr */
+#undef HAVE_STRUCT_IN6_ADDR
+
+/* Have struct sockaddr_in6 */
+#undef HAVE_STRUCT_SOCKADDR_IN6
+
+/* Define to 1 if the system has the type `struct sockaddr_storage'. */
+#undef HAVE_STRUCT_SOCKADDR_STORAGE
+
+/* Define to 1 if `ss_family' is a member of `struct sockaddr_storage'. */
+#undef HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY
+
+/* Define to 1 if `ut_addr' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_ADDR
+
+/* Define to 1 if `ut_addr_v6' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_ADDR_V6
+
+/* Define to 1 if `ut_host' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_HOST
+
+/* Define to 1 if `ut_id' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_ID
+
+/* Define to 1 if `ut_syslen' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_SYSLEN
+
+/* Define to 1 if `ut_time' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_TIME
+
+/* Define to 1 if `ut_tv' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_TV
+
+/* Define to 1 if `ut_type' is a member of `struct utmpx'. */
+#undef HAVE_STRUCT_UTMPX_UT_TYPE
+
+/* Define to 1 if `ut_addr' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_ADDR
+
+/* Define to 1 if `ut_addr_v6' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_ADDR_V6
+
+/* Define to 1 if `ut_exit' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_EXIT
+
+/* Define to 1 if `ut_host' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_HOST
+
+/* Define to 1 if `ut_id' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_ID
+
+/* Define to 1 if `ut_pid' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_PID
+
+/* Define to 1 if `ut_time' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_TIME
+
+/* Define to 1 if `ut_tv' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_TV
+
+/* Define to 1 if `ut_type' is a member of `struct utmp'. */
+#undef HAVE_STRUCT_UTMP_UT_TYPE
+
+/* Define to 1 if you have the <sys/random.h> header file. */
+#undef HAVE_SYS_RANDOM_H
+
+/* Define to 1 if you have the <sys/select.h> header file. */
+#undef HAVE_SYS_SELECT_H
+
+/* Define to 1 if you have the <sys/socket.h> header file. */
+#undef HAVE_SYS_SOCKET_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <sys/uio.h> header file. */
+#undef HAVE_SYS_UIO_H
+
+/* Define to 1 if you have <sys/wait.h> that is POSIX.1 compatible. */
+#undef HAVE_SYS_WAIT_H
+
+/* Define to 1 if the system has the type `uint16_t'. */
+#undef HAVE_UINT16_T
+
+/* Define to 1 if the system has the type `uint32_t'. */
+#undef HAVE_UINT32_T
+
+/* Define to 1 if the system has the type `uint8_t'. */
+#undef HAVE_UINT8_T
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Define to 1 if you have the `updwtmp' function. */
+#undef HAVE_UPDWTMP
+
+/* Define to 1 if you have the <util.h> header file. */
+#undef HAVE_UTIL_H
+
+/* Define to 1 if you have the `utmpname' function. */
+#undef HAVE_UTMPNAME
+
+/* Define to 1 if you have the `utmpxname' function. */
+#undef HAVE_UTMPXNAME
+
+/* Define to 1 if you have the <utmpx.h> header file. */
+#undef HAVE_UTMPX_H
+
+/* Define to 1 if you have the <utmp.h> header file. */
+#undef HAVE_UTMP_H
+
+/* Define to 1 if the system has the type `u_int16_t'. */
+#undef HAVE_U_INT16_T
+
+/* Define to 1 if the system has the type `u_int32_t'. */
+#undef HAVE_U_INT32_T
+
+/* Define to 1 if the system has the type `u_int8_t'. */
+#undef HAVE_U_INT8_T
+
+/* Define to 1 if you have the `writev' function. */
+#undef HAVE_WRITEV
+
+/* Define to 1 if you have the `_getpty' function. */
+#undef HAVE__GETPTY
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Define to the type of arg 1 for `select'. */
+#undef SELECT_TYPE_ARG1
+
+/* Define to the type of args 2, 3 and 4 for `select'. */
+#undef SELECT_TYPE_ARG234
+
+/* Define to the type of arg 5 for `select'. */
+#undef SELECT_TYPE_ARG5
+
+/* Define to 1 if you have the ANSI C header files. */
+#undef STDC_HEADERS
+
+/* Use /dev/ptmx */
+#undef USE_DEV_PTMX
+
+/* Enable large inode numbers on Mac OS X 10.5.  */
+#ifndef _DARWIN_USE_64_BIT_INODE
+# define _DARWIN_USE_64_BIT_INODE 1
+#endif
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+#undef _FILE_OFFSET_BITS
+
+/* Use GNU extensions if glibc */
+#undef _GNU_SOURCE
+
+/* Define for large files, on AIX-style hosts. */
+#undef _LARGE_FILES
+
+/* Define to empty if `const' does not conform to ANSI C. */
+#undef const
+
+/* Define to `int' if <sys/types.h> doesn't define. */
+#undef gid_t
+
+/* Define to `int' if <sys/types.h> does not define. */
+#undef mode_t
+
+/* Define to `int' if <sys/types.h> does not define. */
+#undef pid_t
+
+/* Define to `unsigned int' if <sys/types.h> does not define. */
+#undef size_t
+
+/* type to use in place of socklen_t if not defined */
+#undef socklen_t
+
+/* Define to `int' if <sys/types.h> doesn't define. */
+#undef uid_t

configure.ac

@@ -5,10 +5,18 @@
 # of the platform checks have been taken straight from OpenSSH's configure.ac
 # Huge thanks to them for dealing with the horrible platform-specifics :)
 
-AC_PREREQ(2.59)
+AC_PREREQ([2.59])
 AC_INIT
 AC_CONFIG_SRCDIR(buffer.c)
 
+# Record which revision is being built
+if test -s "`which hg`" && test -d "$srcdir/.hg"; then
+	hgrev=`hg id -i -R "$srcdir"`
+	AC_MSG_NOTICE([Source directory Mercurial base revision $hgrev])
+fi
+
+ORIGCFLAGS="$CFLAGS"
+LATE_CFLAGS=""
 # Checks for programs.
 AC_PROG_CC
 
@@ -29,7 +37,7 @@ AC_DEFUN(DB_TRYADDCFLAGS,
 }])
 
 # set compile flags prior to other tests
-if test -z "$OLDCFLAGS" && test "$GCC" = "yes"; then
+if test -z "$ORIGCFLAGS" && test "$GCC" = "yes"; then
 	AC_MSG_NOTICE(No \$CFLAGS set... using "-Os -W -Wall" for GCC)
 	CFLAGS="-Os -W -Wall"
 fi
@@ -40,6 +48,9 @@ DB_TRYADDCFLAGS([-Wno-pointer-sign])
 AC_MSG_NOTICE([Checking if compiler '$CC' supports -fno-strict-overflow])
 DB_TRYADDCFLAGS([-fno-strict-overflow])
 
+# needed for various extensions. define early before autoconf tests
+AC_DEFINE([_GNU_SOURCE], [], [Use GNU extensions if glibc])
+
 STATIC=0
 AC_ARG_ENABLE(static,
 	[  --enable-static         Build static binaries],
@@ -117,6 +128,17 @@ if test "$hardenbuild" -eq 1; then
 
 fi
 
+AC_ARG_ENABLE(werror,
+	[  --enable-werror         Set -Werror when building],
+	[
+		if test "x$enableval" = "xyes"; then
+			# -Werror shouldn't be set when configure runs tests.
+			# We add it to the Makefile's CFLAGS
+			LATE_CFLAGS+="$LATE_CFLAGS -Werror"
+			AC_MSG_NOTICE(Enabling -Werror)
+		fi
+	], [])
+
 # large file support is useful for scp
 AC_SYS_LARGEFILE
 
@@ -315,16 +337,56 @@ AC_ARG_ENABLE(shadow,
 		AC_MSG_NOTICE(Using shadow passwords if available)
 	]
 )
-			
+
+AC_ARG_ENABLE(plugin,
+	[  --enable-plugin         Enable support for External Public Key Authentication plug-in],
+	[
+		AC_DEFINE(DROPBEAR_PLUGIN, 1, External Public Key Authentication)
+		AC_MSG_NOTICE(Enabling support for External Public Key Authentication)
+		DROPBEAR_PLUGIN=1
+	],
+	[
+		AC_DEFINE(DROPBEAR_PLUGIN, 0, External Public Key Authentication)
+		DROPBEAR_PLUGIN=0
+	]
+
+)
+AC_SUBST(DROPBEAR_PLUGIN)
+
+AC_ARG_ENABLE(fuzz,
+	[  --enable-fuzz           Build fuzzing. Not recommended for deployment.],
+	[
+		if test "x$enableval" = "xyes"; then
+            AC_DEFINE(DROPBEAR_FUZZ, 1, Fuzzing)
+            AC_MSG_NOTICE(Enabling fuzzing)
+            DROPBEAR_FUZZ=1
+            # libfuzzer needs linking with c++ libraries
+            AC_PROG_CXX
+			mkdir -pv fuzz
+        else
+            AC_DEFINE(DROPBEAR_FUZZ, 0, Fuzzing)
+            AC_MSG_NOTICE(Disabling fuzzing)
+            DROPBEAR_FUZZ=0
+        fi
+	],
+	[
+		AC_DEFINE(DROPBEAR_FUZZ, 0, Fuzzing)
+		AC_MSG_NOTICE(Disabling fuzzing)
+		DROPBEAR_FUZZ=0
+	]
+
+)
+AC_SUBST(DROPBEAR_FUZZ)
+AC_SUBST(CXX)
 
 # Checks for header files.
-AC_HEADER_STDC
 AC_HEADER_SYS_WAIT
 AC_CHECK_HEADERS([netinet/in.h netinet/tcp.h \
 	crypt.h \
 	pty.h libutil.h libgen.h inttypes.h stropts.h utmp.h \
 	utmpx.h lastlog.h paths.h util.h netdb.h security/pam_appl.h \
-	pam/pam_appl.h netinet/in_systm.h sys/uio.h linux/pkt_sched.h])
+	pam/pam_appl.h netinet/in_systm.h sys/uio.h linux/pkt_sched.h \
+	sys/random.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST
@@ -332,7 +394,6 @@ AC_TYPE_UID_T
 AC_TYPE_MODE_T
 AC_TYPE_PID_T
 AC_TYPE_SIZE_T
-AC_HEADER_TIME
 
 AC_CHECK_TYPES([uint8_t, u_int8_t, uint16_t, u_int16_t, uint32_t, u_int32_t])
 AC_CHECK_TYPES([struct sockaddr_storage])
@@ -473,32 +534,36 @@ AC_CHECK_FUNCS(endutxent getutxent getutxid getutxline pututxline )
 AC_CHECK_FUNCS(setutxent utmpxname)
 AC_CHECK_FUNCS(logout updwtmp logwtmp)
 
+# POSIX monotonic time
+AC_CHECK_FUNCS(clock_gettime)
+
 # OS X monotonic time
 AC_CHECK_HEADERS([mach/mach_time.h])
 AC_CHECK_FUNCS(mach_absolute_time)
 
-AC_CHECK_FUNCS(explicit_bzero memset_s)
+AC_CHECK_FUNCS(explicit_bzero memset_s getrandom)
 
 AC_ARG_ENABLE(bundled-libtom,
 [  --enable-bundled-libtom       Force using bundled libtomcrypt/libtommath even if a system version exists.
   --disable-bundled-libtom      Force using system libtomcrypt/libtommath, fail if it does not exist.
-                                Default is to use system if available, otherwise bundled.],
+                                Default is to use system if available, otherwise bundled.
+                                Dropbear requires system libtommath >= 1.2.0 and libtomcrypt >= 1.18.0],
 	[
 		if test "x$enableval" = "xyes"; then
 			BUNDLED_LIBTOM=1
 			AC_MSG_NOTICE(Forcing bundled libtom*)
 		else
 			BUNDLED_LIBTOM=0
-			AC_CHECK_LIB(tommath, mp_exptmod, LIBTOM_LIBS="-ltommath $LIBTOM_LIBS",
-				[AC_MSG_ERROR([Missing system libtommath and --disable-bundled-libtom was specified])] )
-			AC_CHECK_LIB(tomcrypt, register_cipher, LIBTOM_LIBS="-ltomcrypt $LIBTOM_LIBS",
-				[AC_MSG_ERROR([Missing system libtomcrypt and --disable-bundled-libtom was specified])] )
+			AC_CHECK_LIB(tommath, mp_to_ubin, LIBTOM_LIBS="-ltommath $LIBTOM_LIBS",
+				[AC_MSG_ERROR([Missing/old system libtommath and --disable-bundled-libtom was specified])] )
+			AC_CHECK_LIB(tomcrypt, poly1305_init, LIBTOM_LIBS="-ltomcrypt $LIBTOM_LIBS",
+				[AC_MSG_ERROR([Missing/old system libtomcrypt and --disable-bundled-libtom was specified])] )
 		fi
 	],
 	[
 		BUNDLED_LIBTOM=0
-		AC_CHECK_LIB(tommath, mp_exptmod, LIBTOM_LIBS="-ltommath $LIBTOM_LIBS", BUNDLED_LIBTOM=1)
-		AC_CHECK_LIB(tomcrypt, register_cipher, LIBTOM_LIBS="-ltomcrypt $LIBTOM_LIBS", BUNDLED_LIBTOM=1)
+		AC_CHECK_LIB(tommath, mp_to_ubin, LIBTOM_LIBS="-ltommath $LIBTOM_LIBS", BUNDLED_LIBTOM=1)
+		AC_CHECK_LIB(tomcrypt, poly1305_init, LIBTOM_LIBS="-ltomcrypt $LIBTOM_LIBS", BUNDLED_LIBTOM=1)
 	]
 )
 
@@ -808,8 +873,11 @@ if test $BUNDLED_LIBTOM = 1 ; then
 LIBTOM_FILES="libtomcrypt/Makefile libtommath/Makefile"
 fi
 
-AC_CONFIG_HEADER(config.h)
-AC_CONFIG_FILES(Makefile $LIBTOM_FILES)
+# flags that should be set in Makefile but not for configure tests
+CFLAGS="$CFLAGS $LATE_CFLAGS"
+
+AC_CONFIG_HEADERS([config.h])
+AC_CONFIG_FILES(Makefile $LIBTOM_FILES test/Makefile)
 AC_OUTPUT
 
 AC_MSG_NOTICE()
@@ -831,4 +899,4 @@ AC_MSG_NOTICE([crypt() not available, dropbear server will not have password aut
 fi
 
 AC_MSG_NOTICE()
-AC_MSG_NOTICE([Now edit options.h to choose features.])
+AC_MSG_NOTICE([Now edit localoptions.h to choose features.])

crypto_desc.c

@@ -3,11 +3,18 @@
 #include "crypto_desc.h"
 #include "ltc_prng.h"
 #include "ecc.h"
+#include "dbrandom.h"
 
 #if DROPBEAR_LTC_PRNG
 	int dropbear_ltc_prng = -1;
 #endif
 
+/* Wrapper for libtommath */
+static mp_err dropbear_rand_source(void* out, size_t size) {
+	genrandom((unsigned char*)out, (unsigned int)size);
+	return MP_OKAY;
+}
+
 
 /* Register the compiled in ciphers.
  * This should be run before using any of the ciphers/hashes */
@@ -67,6 +74,8 @@ void crypto_init() {
 	}
 #endif
 
+	mp_rand_source(dropbear_rand_source);
+
 #if DROPBEAR_ECC
 	ltc_mp = ltm_desc;
 	dropbear_ecc_fill_dp();

curve25519-donna.c

@@ -1,860 +0,0 @@
-/* Copyright 2008, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * curve25519-donna: Curve25519 elliptic curve, public key function
- *
- * http://code.google.com/p/curve25519-donna/
- *
- * Adam Langley <agl@imperialviolet.org>
- *
- * Derived from public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
- *
- * More information about curve25519 can be found here
- *   http://cr.yp.to/ecdh.html
- *
- * djb's sample implementation of curve25519 is written in a special assembly
- * language called qhasm and uses the floating point registers.
- *
- * This is, almost, a clean room reimplementation from the curve25519 paper. It
- * uses many of the tricks described therein. Only the crecip function is taken
- * from the sample implementation. */
-
-#include <string.h>
-#include <stdint.h>
-
-#ifdef _MSC_VER
-#define inline __inline
-#endif
-
-typedef uint8_t u8;
-typedef int32_t s32;
-typedef int64_t limb;
-
-/* Field element representation:
- *
- * Field elements are written as an array of signed, 64-bit limbs, least
- * significant first. The value of the field element is:
- *   x[0] + 2^26·x[1] + x^51·x[2] + 2^102·x[3] + ...
- *
- * i.e. the limbs are 26, 25, 26, 25, ... bits wide. */
-
-/* Sum two numbers: output += in */
-static void fsum(limb *output, const limb *in) {
-  unsigned i;
-  for (i = 0; i < 10; i += 2) {
-    output[0+i] = output[0+i] + in[0+i];
-    output[1+i] = output[1+i] + in[1+i];
-  }
-}
-
-/* Find the difference of two numbers: output = in - output
- * (note the order of the arguments!). */
-static void fdifference(limb *output, const limb *in) {
-  unsigned i;
-  for (i = 0; i < 10; ++i) {
-    output[i] = in[i] - output[i];
-  }
-}
-
-/* Multiply a number by a scalar: output = in * scalar */
-static void fscalar_product(limb *output, const limb *in, const limb scalar) {
-  unsigned i;
-  for (i = 0; i < 10; ++i) {
-    output[i] = in[i] * scalar;
-  }
-}
-
-/* Multiply two numbers: output = in2 * in
- *
- * output must be distinct to both inputs. The inputs are reduced coefficient
- * form, the output is not.
- *
- * output[x] <= 14 * the largest product of the input limbs. */
-static void fproduct(limb *output, const limb *in2, const limb *in) {
-  output[0] =       ((limb) ((s32) in2[0])) * ((s32) in[0]);
-  output[1] =       ((limb) ((s32) in2[0])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[0]);
-  output[2] =  2 *  ((limb) ((s32) in2[1])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[0]);
-  output[3] =       ((limb) ((s32) in2[1])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[0]);
-  output[4] =       ((limb) ((s32) in2[2])) * ((s32) in[2]) +
-               2 * (((limb) ((s32) in2[1])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[1])) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[0]);
-  output[5] =       ((limb) ((s32) in2[2])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[0]);
-  output[6] =  2 * (((limb) ((s32) in2[3])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[1])) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[0]);
-  output[7] =       ((limb) ((s32) in2[3])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[0]);
-  output[8] =       ((limb) ((s32) in2[4])) * ((s32) in[4]) +
-               2 * (((limb) ((s32) in2[3])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[1])) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[0]);
-  output[9] =       ((limb) ((s32) in2[4])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[2]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[1]) +
-                    ((limb) ((s32) in2[0])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[0]);
-  output[10] = 2 * (((limb) ((s32) in2[5])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[1])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[1])) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[2]);
-  output[11] =      ((limb) ((s32) in2[5])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[4]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[3]) +
-                    ((limb) ((s32) in2[2])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[2]);
-  output[12] =      ((limb) ((s32) in2[6])) * ((s32) in[6]) +
-               2 * (((limb) ((s32) in2[5])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[3])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[3])) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[4]);
-  output[13] =      ((limb) ((s32) in2[6])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[7])) * ((s32) in[6]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[5]) +
-                    ((limb) ((s32) in2[4])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[4]);
-  output[14] = 2 * (((limb) ((s32) in2[7])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[5])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[5])) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[6]);
-  output[15] =      ((limb) ((s32) in2[7])) * ((s32) in[8]) +
-                    ((limb) ((s32) in2[8])) * ((s32) in[7]) +
-                    ((limb) ((s32) in2[6])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[6]);
-  output[16] =      ((limb) ((s32) in2[8])) * ((s32) in[8]) +
-               2 * (((limb) ((s32) in2[7])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[7]));
-  output[17] =      ((limb) ((s32) in2[8])) * ((s32) in[9]) +
-                    ((limb) ((s32) in2[9])) * ((s32) in[8]);
-  output[18] = 2 *  ((limb) ((s32) in2[9])) * ((s32) in[9]);
-}
-
-/* Reduce a long form to a short form by taking the input mod 2^255 - 19.
- *
- * On entry: |output[i]| < 14*2^54
- * On exit: |output[0..8]| < 280*2^54 */
-static void freduce_degree(limb *output) {
-  /* Each of these shifts and adds ends up multiplying the value by 19.
-   *
-   * For output[0..8], the absolute entry value is < 14*2^54 and we add, at
-   * most, 19*14*2^54 thus, on exit, |output[0..8]| < 280*2^54. */
-  output[8] += output[18] << 4;
-  output[8] += output[18] << 1;
-  output[8] += output[18];
-  output[7] += output[17] << 4;
-  output[7] += output[17] << 1;
-  output[7] += output[17];
-  output[6] += output[16] << 4;
-  output[6] += output[16] << 1;
-  output[6] += output[16];
-  output[5] += output[15] << 4;
-  output[5] += output[15] << 1;
-  output[5] += output[15];
-  output[4] += output[14] << 4;
-  output[4] += output[14] << 1;
-  output[4] += output[14];
-  output[3] += output[13] << 4;
-  output[3] += output[13] << 1;
-  output[3] += output[13];
-  output[2] += output[12] << 4;
-  output[2] += output[12] << 1;
-  output[2] += output[12];
-  output[1] += output[11] << 4;
-  output[1] += output[11] << 1;
-  output[1] += output[11];
-  output[0] += output[10] << 4;
-  output[0] += output[10] << 1;
-  output[0] += output[10];
-}
-
-#if (-1 & 3) != 3
-#error "This code only works on a two's complement system"
-#endif
-
-/* return v / 2^26, using only shifts and adds.
- *
- * On entry: v can take any value. */
-static inline limb
-div_by_2_26(const limb v)
-{
-  /* High word of v; no shift needed. */
-  const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
-  /* Set to all 1s if v was negative; else set to 0s. */
-  const int32_t sign = ((int32_t) highword) >> 31;
-  /* Set to 0x3ffffff if v was negative; else set to 0. */
-  const int32_t roundoff = ((uint32_t) sign) >> 6;
-  /* Should return v / (1<<26) */
-  return (v + roundoff) >> 26;
-}
-
-/* return v / (2^25), using only shifts and adds.
- *
- * On entry: v can take any value. */
-static inline limb
-div_by_2_25(const limb v)
-{
-  /* High word of v; no shift needed*/
-  const uint32_t highword = (uint32_t) (((uint64_t) v) >> 32);
-  /* Set to all 1s if v was negative; else set to 0s. */
-  const int32_t sign = ((int32_t) highword) >> 31;
-  /* Set to 0x1ffffff if v was negative; else set to 0. */
-  const int32_t roundoff = ((uint32_t) sign) >> 7;
-  /* Should return v / (1<<25) */
-  return (v + roundoff) >> 25;
-}
-
-/* Reduce all coefficients of the short form input so that |x| < 2^26.
- *
- * On entry: |output[i]| < 280*2^54 */
-static void freduce_coefficients(limb *output) {
-  unsigned i;
-
-  output[10] = 0;
-
-  for (i = 0; i < 10; i += 2) {
-    limb over = div_by_2_26(output[i]);
-    /* The entry condition (that |output[i]| < 280*2^54) means that over is, at
-     * most, 280*2^28 in the first iteration of this loop. This is added to the
-     * next limb and we can approximate the resulting bound of that limb by
-     * 281*2^54. */
-    output[i] -= over << 26;
-    output[i+1] += over;
-
-    /* For the first iteration, |output[i+1]| < 281*2^54, thus |over| <
-     * 281*2^29. When this is added to the next limb, the resulting bound can
-     * be approximated as 281*2^54.
-     *
-     * For subsequent iterations of the loop, 281*2^54 remains a conservative
-     * bound and no overflow occurs. */
-    over = div_by_2_25(output[i+1]);
-    output[i+1] -= over << 25;
-    output[i+2] += over;
-  }
-  /* Now |output[10]| < 281*2^29 and all other coefficients are reduced. */
-  output[0] += output[10] << 4;
-  output[0] += output[10] << 1;
-  output[0] += output[10];
-
-  output[10] = 0;
-
-  /* Now output[1..9] are reduced, and |output[0]| < 2^26 + 19*281*2^29
-   * So |over| will be no more than 2^16. */
-  {
-    limb over = div_by_2_26(output[0]);
-    output[0] -= over << 26;
-    output[1] += over;
-  }
-
-  /* Now output[0,2..9] are reduced, and |output[1]| < 2^25 + 2^16 < 2^26. The
-   * bound on |output[1]| is sufficient to meet our needs. */
-}
-
-/* A helpful wrapper around fproduct: output = in * in2.
- *
- * On entry: |in[i]| < 2^27 and |in2[i]| < 2^27.
- *
- * output must be distinct to both inputs. The output is reduced degree
- * (indeed, one need only provide storage for 10 limbs) and |output[i]| < 2^26. */
-static void
-fmul(limb *output, const limb *in, const limb *in2) {
-  limb t[19];
-  fproduct(t, in, in2);
-  /* |t[i]| < 14*2^54 */
-  freduce_degree(t);
-  freduce_coefficients(t);
-  /* |t[i]| < 2^26 */
-  memcpy(output, t, sizeof(limb) * 10);
-}
-
-/* Square a number: output = in**2
- *
- * output must be distinct from the input. The inputs are reduced coefficient
- * form, the output is not.
- *
- * output[x] <= 14 * the largest product of the input limbs. */
-static void fsquare_inner(limb *output, const limb *in) {
-  output[0] =       ((limb) ((s32) in[0])) * ((s32) in[0]);
-  output[1] =  2 *  ((limb) ((s32) in[0])) * ((s32) in[1]);
-  output[2] =  2 * (((limb) ((s32) in[1])) * ((s32) in[1]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[2]));
-  output[3] =  2 * (((limb) ((s32) in[1])) * ((s32) in[2]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[3]));
-  output[4] =       ((limb) ((s32) in[2])) * ((s32) in[2]) +
-               4 *  ((limb) ((s32) in[1])) * ((s32) in[3]) +
-               2 *  ((limb) ((s32) in[0])) * ((s32) in[4]);
-  output[5] =  2 * (((limb) ((s32) in[2])) * ((s32) in[3]) +
-                    ((limb) ((s32) in[1])) * ((s32) in[4]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[5]));
-  output[6] =  2 * (((limb) ((s32) in[3])) * ((s32) in[3]) +
-                    ((limb) ((s32) in[2])) * ((s32) in[4]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[6]) +
-               2 *  ((limb) ((s32) in[1])) * ((s32) in[5]));
-  output[7] =  2 * (((limb) ((s32) in[3])) * ((s32) in[4]) +
-                    ((limb) ((s32) in[2])) * ((s32) in[5]) +
-                    ((limb) ((s32) in[1])) * ((s32) in[6]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[7]));
-  output[8] =       ((limb) ((s32) in[4])) * ((s32) in[4]) +
-               2 * (((limb) ((s32) in[2])) * ((s32) in[6]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[8]) +
-               2 * (((limb) ((s32) in[1])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[3])) * ((s32) in[5])));
-  output[9] =  2 * (((limb) ((s32) in[4])) * ((s32) in[5]) +
-                    ((limb) ((s32) in[3])) * ((s32) in[6]) +
-                    ((limb) ((s32) in[2])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[1])) * ((s32) in[8]) +
-                    ((limb) ((s32) in[0])) * ((s32) in[9]));
-  output[10] = 2 * (((limb) ((s32) in[5])) * ((s32) in[5]) +
-                    ((limb) ((s32) in[4])) * ((s32) in[6]) +
-                    ((limb) ((s32) in[2])) * ((s32) in[8]) +
-               2 * (((limb) ((s32) in[3])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[1])) * ((s32) in[9])));
-  output[11] = 2 * (((limb) ((s32) in[5])) * ((s32) in[6]) +
-                    ((limb) ((s32) in[4])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[3])) * ((s32) in[8]) +
-                    ((limb) ((s32) in[2])) * ((s32) in[9]));
-  output[12] =      ((limb) ((s32) in[6])) * ((s32) in[6]) +
-               2 * (((limb) ((s32) in[4])) * ((s32) in[8]) +
-               2 * (((limb) ((s32) in[5])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[3])) * ((s32) in[9])));
-  output[13] = 2 * (((limb) ((s32) in[6])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[5])) * ((s32) in[8]) +
-                    ((limb) ((s32) in[4])) * ((s32) in[9]));
-  output[14] = 2 * (((limb) ((s32) in[7])) * ((s32) in[7]) +
-                    ((limb) ((s32) in[6])) * ((s32) in[8]) +
-               2 *  ((limb) ((s32) in[5])) * ((s32) in[9]));
-  output[15] = 2 * (((limb) ((s32) in[7])) * ((s32) in[8]) +
-                    ((limb) ((s32) in[6])) * ((s32) in[9]));
-  output[16] =      ((limb) ((s32) in[8])) * ((s32) in[8]) +
-               4 *  ((limb) ((s32) in[7])) * ((s32) in[9]);
-  output[17] = 2 *  ((limb) ((s32) in[8])) * ((s32) in[9]);
-  output[18] = 2 *  ((limb) ((s32) in[9])) * ((s32) in[9]);
-}
-
-/* fsquare sets output = in^2.
- *
- * On entry: The |in| argument is in reduced coefficients form and |in[i]| <
- * 2^27.
- *
- * On exit: The |output| argument is in reduced coefficients form (indeed, one
- * need only provide storage for 10 limbs) and |out[i]| < 2^26. */
-static void
-fsquare(limb *output, const limb *in) {
-  limb t[19];
-  fsquare_inner(t, in);
-  /* |t[i]| < 14*2^54 because the largest product of two limbs will be <
-   * 2^(27+27) and fsquare_inner adds together, at most, 14 of those
-   * products. */
-  freduce_degree(t);
-  freduce_coefficients(t);
-  /* |t[i]| < 2^26 */
-  memcpy(output, t, sizeof(limb) * 10);
-}
-
-/* Take a little-endian, 32-byte number and expand it into polynomial form */
-static void
-fexpand(limb *output, const u8 *input) {
-#define F(n,start,shift,mask) \
-  output[n] = ((((limb) input[start + 0]) | \
-                ((limb) input[start + 1]) << 8 | \
-                ((limb) input[start + 2]) << 16 | \
-                ((limb) input[start + 3]) << 24) >> shift) & mask;
-  F(0, 0, 0, 0x3ffffff);
-  F(1, 3, 2, 0x1ffffff);
-  F(2, 6, 3, 0x3ffffff);
-  F(3, 9, 5, 0x1ffffff);
-  F(4, 12, 6, 0x3ffffff);
-  F(5, 16, 0, 0x1ffffff);
-  F(6, 19, 1, 0x3ffffff);
-  F(7, 22, 3, 0x1ffffff);
-  F(8, 25, 4, 0x3ffffff);
-  F(9, 28, 6, 0x1ffffff);
-#undef F
-}
-
-#if (-32 >> 1) != -16
-#error "This code only works when >> does sign-extension on negative numbers"
-#endif
-
-/* s32_eq returns 0xffffffff iff a == b and zero otherwise. */
-static s32 s32_eq(s32 a, s32 b) {
-  a = ~(a ^ b);
-  a &= a << 16;
-  a &= a << 8;
-  a &= a << 4;
-  a &= a << 2;
-  a &= a << 1;
-  return a >> 31;
-}
-
-/* s32_gte returns 0xffffffff if a >= b and zero otherwise, where a and b are
- * both non-negative. */
-static s32 s32_gte(s32 a, s32 b) {
-  a -= b;
-  /* a >= 0 iff a >= b. */
-  return ~(a >> 31);
-}
-
-/* Take a fully reduced polynomial form number and contract it into a
- * little-endian, 32-byte array.
- *
- * On entry: |input_limbs[i]| < 2^26 */
-static void
-fcontract(u8 *output, limb *input_limbs) {
-  int i;
-  int j;
-  s32 input[10];
-  s32 mask;
-
-  /* |input_limbs[i]| < 2^26, so it's valid to convert to an s32. */
-  for (i = 0; i < 10; i++) {
-    input[i] = input_limbs[i];
-  }
-
-  for (j = 0; j < 2; ++j) {
-    for (i = 0; i < 9; ++i) {
-      if ((i & 1) == 1) {
-        /* This calculation is a time-invariant way to make input[i]
-         * non-negative by borrowing from the next-larger limb. */
-        const s32 mask = input[i] >> 31;
-        const s32 carry = -((input[i] & mask) >> 25);
-        input[i] = input[i] + (carry << 25);
-        input[i+1] = input[i+1] - carry;
-      } else {
-        const s32 mask = input[i] >> 31;
-        const s32 carry = -((input[i] & mask) >> 26);
-        input[i] = input[i] + (carry << 26);
-        input[i+1] = input[i+1] - carry;
-      }
-    }
-
-    /* There's no greater limb for input[9] to borrow from, but we can multiply
-     * by 19 and borrow from input[0], which is valid mod 2^255-19. */
-    {
-      const s32 mask = input[9] >> 31;
-      const s32 carry = -((input[9] & mask) >> 25);
-      input[9] = input[9] + (carry << 25);
-      input[0] = input[0] - (carry * 19);
-    }
-
-    /* After the first iteration, input[1..9] are non-negative and fit within
-     * 25 or 26 bits, depending on position. However, input[0] may be
-     * negative. */
-  }
-
-  /* The first borrow-propagation pass above ended with every limb
-     except (possibly) input[0] non-negative.
-
-     If input[0] was negative after the first pass, then it was because of a
-     carry from input[9]. On entry, input[9] < 2^26 so the carry was, at most,
-     one, since (2**26-1) >> 25 = 1. Thus input[0] >= -19.
-
-     In the second pass, each limb is decreased by at most one. Thus the second
-     borrow-propagation pass could only have wrapped around to decrease
-     input[0] again if the first pass left input[0] negative *and* input[1]
-     through input[9] were all zero.  In that case, input[1] is now 2^25 - 1,
-     and this last borrow-propagation step will leave input[1] non-negative. */
-  {
-    const s32 mask = input[0] >> 31;
-    const s32 carry = -((input[0] & mask) >> 26);
-    input[0] = input[0] + (carry << 26);
-    input[1] = input[1] - carry;
-  }
-
-  /* All input[i] are now non-negative. However, there might be values between
-   * 2^25 and 2^26 in a limb which is, nominally, 25 bits wide. */
-  for (j = 0; j < 2; j++) {
-    for (i = 0; i < 9; i++) {
-      if ((i & 1) == 1) {
-        const s32 carry = input[i] >> 25;
-        input[i] &= 0x1ffffff;
-        input[i+1] += carry;
-      } else {
-        const s32 carry = input[i] >> 26;
-        input[i] &= 0x3ffffff;
-        input[i+1] += carry;
-      }
-    }
-
-    {
-      const s32 carry = input[9] >> 25;
-      input[9] &= 0x1ffffff;
-      input[0] += 19*carry;
-    }
-  }
-
-  /* If the first carry-chain pass, just above, ended up with a carry from
-   * input[9], and that caused input[0] to be out-of-bounds, then input[0] was
-   * < 2^26 + 2*19, because the carry was, at most, two.
-   *
-   * If the second pass carried from input[9] again then input[0] is < 2*19 and
-   * the input[9] -> input[0] carry didn't push input[0] out of bounds. */
-
-  /* It still remains the case that input might be between 2^255-19 and 2^255.
-   * In this case, input[1..9] must take their maximum value and input[0] must
-   * be >= (2^255-19) & 0x3ffffff, which is 0x3ffffed. */
-  mask = s32_gte(input[0], 0x3ffffed);
-  for (i = 1; i < 10; i++) {
-    if ((i & 1) == 1) {
-      mask &= s32_eq(input[i], 0x1ffffff);
-    } else {
-      mask &= s32_eq(input[i], 0x3ffffff);
-    }
-  }
-
-  /* mask is either 0xffffffff (if input >= 2^255-19) and zero otherwise. Thus
-   * this conditionally subtracts 2^255-19. */
-  input[0] -= mask & 0x3ffffed;
-
-  for (i = 1; i < 10; i++) {
-    if ((i & 1) == 1) {
-      input[i] -= mask & 0x1ffffff;
-    } else {
-      input[i] -= mask & 0x3ffffff;
-    }
-  }
-
-  input[1] <<= 2;
-  input[2] <<= 3;
-  input[3] <<= 5;
-  input[4] <<= 6;
-  input[6] <<= 1;
-  input[7] <<= 3;
-  input[8] <<= 4;
-  input[9] <<= 6;
-#define F(i, s) \
-  output[s+0] |=  input[i] & 0xff; \
-  output[s+1]  = (input[i] >> 8) & 0xff; \
-  output[s+2]  = (input[i] >> 16) & 0xff; \
-  output[s+3]  = (input[i] >> 24) & 0xff;
-  output[0] = 0;
-  output[16] = 0;
-  F(0,0);
-  F(1,3);
-  F(2,6);
-  F(3,9);
-  F(4,12);
-  F(5,16);
-  F(6,19);
-  F(7,22);
-  F(8,25);
-  F(9,28);
-#undef F
-}
-
-/* Input: Q, Q', Q-Q'
- * Output: 2Q, Q+Q'
- *
- *   x2 z3: long form
- *   x3 z3: long form
- *   x z: short form, destroyed
- *   xprime zprime: short form, destroyed
- *   qmqp: short form, preserved
- *
- * On entry and exit, the absolute value of the limbs of all inputs and outputs
- * are < 2^26. */
-static void fmonty(limb *x2, limb *z2,  /* output 2Q */
-                   limb *x3, limb *z3,  /* output Q + Q' */
-                   limb *x, limb *z,    /* input Q */
-                   limb *xprime, limb *zprime,  /* input Q' */
-                   const limb *qmqp /* input Q - Q' */) {
-  limb origx[10], origxprime[10], zzz[19], xx[19], zz[19], xxprime[19],
-        zzprime[19], zzzprime[19], xxxprime[19];
-
-  memcpy(origx, x, 10 * sizeof(limb));
-  fsum(x, z);
-  /* |x[i]| < 2^27 */
-  fdifference(z, origx);  /* does x - z */
-  /* |z[i]| < 2^27 */
-
-  memcpy(origxprime, xprime, sizeof(limb) * 10);
-  fsum(xprime, zprime);
-  /* |xprime[i]| < 2^27 */
-  fdifference(zprime, origxprime);
-  /* |zprime[i]| < 2^27 */
-  fproduct(xxprime, xprime, z);
-  /* |xxprime[i]| < 14*2^54: the largest product of two limbs will be <
-   * 2^(27+27) and fproduct adds together, at most, 14 of those products.
-   * (Approximating that to 2^58 doesn't work out.) */
-  fproduct(zzprime, x, zprime);
-  /* |zzprime[i]| < 14*2^54 */
-  freduce_degree(xxprime);
-  freduce_coefficients(xxprime);
-  /* |xxprime[i]| < 2^26 */
-  freduce_degree(zzprime);
-  freduce_coefficients(zzprime);
-  /* |zzprime[i]| < 2^26 */
-  memcpy(origxprime, xxprime, sizeof(limb) * 10);
-  fsum(xxprime, zzprime);
-  /* |xxprime[i]| < 2^27 */
-  fdifference(zzprime, origxprime);
-  /* |zzprime[i]| < 2^27 */
-  fsquare(xxxprime, xxprime);
-  /* |xxxprime[i]| < 2^26 */
-  fsquare(zzzprime, zzprime);
-  /* |zzzprime[i]| < 2^26 */
-  fproduct(zzprime, zzzprime, qmqp);
-  /* |zzprime[i]| < 14*2^52 */
-  freduce_degree(zzprime);
-  freduce_coefficients(zzprime);
-  /* |zzprime[i]| < 2^26 */
-  memcpy(x3, xxxprime, sizeof(limb) * 10);
-  memcpy(z3, zzprime, sizeof(limb) * 10);
-
-  fsquare(xx, x);
-  /* |xx[i]| < 2^26 */
-  fsquare(zz, z);
-  /* |zz[i]| < 2^26 */
-  fproduct(x2, xx, zz);
-  /* |x2[i]| < 14*2^52 */
-  freduce_degree(x2);
-  freduce_coefficients(x2);
-  /* |x2[i]| < 2^26 */
-  fdifference(zz, xx);  /* does zz = xx - zz */
-  /* |zz[i]| < 2^27 */
-  memset(zzz + 10, 0, sizeof(limb) * 9);
-  fscalar_product(zzz, zz, 121665);
-  /* |zzz[i]| < 2^(27+17) */
-  /* No need to call freduce_degree here:
-     fscalar_product doesn't increase the degree of its input. */
-  freduce_coefficients(zzz);
-  /* |zzz[i]| < 2^26 */
-  fsum(zzz, xx);
-  /* |zzz[i]| < 2^27 */
-  fproduct(z2, zz, zzz);
-  /* |z2[i]| < 14*2^(26+27) */
-  freduce_degree(z2);
-  freduce_coefficients(z2);
-  /* |z2|i| < 2^26 */
-}
-
-/* Conditionally swap two reduced-form limb arrays if 'iswap' is 1, but leave
- * them unchanged if 'iswap' is 0.  Runs in data-invariant time to avoid
- * side-channel attacks.
- *
- * NOTE that this function requires that 'iswap' be 1 or 0; other values give
- * wrong results.  Also, the two limb arrays must be in reduced-coefficient,
- * reduced-degree form: the values in a[10..19] or b[10..19] aren't swapped,
- * and all all values in a[0..9],b[0..9] must have magnitude less than
- * INT32_MAX. */
-static void
-swap_conditional(limb a[19], limb b[19], limb iswap) {
-  unsigned i;
-  const s32 swap = (s32) -iswap;
-
-  for (i = 0; i < 10; ++i) {
-    const s32 x = swap & ( ((s32)a[i]) ^ ((s32)b[i]) );
-    a[i] = ((s32)a[i]) ^ x;
-    b[i] = ((s32)b[i]) ^ x;
-  }
-}
-
-/* Calculates nQ where Q is the x-coordinate of a point on the curve
- *
- *   resultx/resultz: the x coordinate of the resulting curve point (short form)
- *   n: a little endian, 32-byte number
- *   q: a point of the curve (short form) */
-static void
-cmult(limb *resultx, limb *resultz, const u8 *n, const limb *q) {
-  limb a[19] = {0}, b[19] = {1}, c[19] = {1}, d[19] = {0};
-  limb *nqpqx = a, *nqpqz = b, *nqx = c, *nqz = d, *t;
-  limb e[19] = {0}, f[19] = {1}, g[19] = {0}, h[19] = {1};
-  limb *nqpqx2 = e, *nqpqz2 = f, *nqx2 = g, *nqz2 = h;
-
-  unsigned i, j;
-
-  memcpy(nqpqx, q, sizeof(limb) * 10);
-
-  for (i = 0; i < 32; ++i) {
-    u8 byte = n[31 - i];
-    for (j = 0; j < 8; ++j) {
-      const limb bit = byte >> 7;
-
-      swap_conditional(nqx, nqpqx, bit);
-      swap_conditional(nqz, nqpqz, bit);
-      fmonty(nqx2, nqz2,
-             nqpqx2, nqpqz2,
-             nqx, nqz,
-             nqpqx, nqpqz,
-             q);
-      swap_conditional(nqx2, nqpqx2, bit);
-      swap_conditional(nqz2, nqpqz2, bit);
-
-      t = nqx;
-      nqx = nqx2;
-      nqx2 = t;
-      t = nqz;
-      nqz = nqz2;
-      nqz2 = t;
-      t = nqpqx;
-      nqpqx = nqpqx2;
-      nqpqx2 = t;
-      t = nqpqz;
-      nqpqz = nqpqz2;
-      nqpqz2 = t;
-
-      byte <<= 1;
-    }
-  }
-
-  memcpy(resultx, nqx, sizeof(limb) * 10);
-  memcpy(resultz, nqz, sizeof(limb) * 10);
-}
-
-/* -----------------------------------------------------------------------------
- * Shamelessly copied from djb's code
- * ----------------------------------------------------------------------------- */
-static void
-crecip(limb *out, const limb *z) {
-  limb z2[10];
-  limb z9[10];
-  limb z11[10];
-  limb z2_5_0[10];
-  limb z2_10_0[10];
-  limb z2_20_0[10];
-  limb z2_50_0[10];
-  limb z2_100_0[10];
-  limb t0[10];
-  limb t1[10];
-  int i;
-
-  /* 2 */ fsquare(z2,z);
-  /* 4 */ fsquare(t1,z2);
-  /* 8 */ fsquare(t0,t1);
-  /* 9 */ fmul(z9,t0,z);
-  /* 11 */ fmul(z11,z9,z2);
-  /* 22 */ fsquare(t0,z11);
-  /* 2^5 - 2^0 = 31 */ fmul(z2_5_0,t0,z9);
-
-  /* 2^6 - 2^1 */ fsquare(t0,z2_5_0);
-  /* 2^7 - 2^2 */ fsquare(t1,t0);
-  /* 2^8 - 2^3 */ fsquare(t0,t1);
-  /* 2^9 - 2^4 */ fsquare(t1,t0);
-  /* 2^10 - 2^5 */ fsquare(t0,t1);
-  /* 2^10 - 2^0 */ fmul(z2_10_0,t0,z2_5_0);
-
-  /* 2^11 - 2^1 */ fsquare(t0,z2_10_0);
-  /* 2^12 - 2^2 */ fsquare(t1,t0);
-  /* 2^20 - 2^10 */ for (i = 2;i < 10;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
-  /* 2^20 - 2^0 */ fmul(z2_20_0,t1,z2_10_0);
-
-  /* 2^21 - 2^1 */ fsquare(t0,z2_20_0);
-  /* 2^22 - 2^2 */ fsquare(t1,t0);
-  /* 2^40 - 2^20 */ for (i = 2;i < 20;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
-  /* 2^40 - 2^0 */ fmul(t0,t1,z2_20_0);
-
-  /* 2^41 - 2^1 */ fsquare(t1,t0);
-  /* 2^42 - 2^2 */ fsquare(t0,t1);
-  /* 2^50 - 2^10 */ for (i = 2;i < 10;i += 2) { fsquare(t1,t0); fsquare(t0,t1); }
-  /* 2^50 - 2^0 */ fmul(z2_50_0,t0,z2_10_0);
-
-  /* 2^51 - 2^1 */ fsquare(t0,z2_50_0);
-  /* 2^52 - 2^2 */ fsquare(t1,t0);
-  /* 2^100 - 2^50 */ for (i = 2;i < 50;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
-  /* 2^100 - 2^0 */ fmul(z2_100_0,t1,z2_50_0);
-
-  /* 2^101 - 2^1 */ fsquare(t1,z2_100_0);
-  /* 2^102 - 2^2 */ fsquare(t0,t1);
-  /* 2^200 - 2^100 */ for (i = 2;i < 100;i += 2) { fsquare(t1,t0); fsquare(t0,t1); }
-  /* 2^200 - 2^0 */ fmul(t1,t0,z2_100_0);
-
-  /* 2^201 - 2^1 */ fsquare(t0,t1);
-  /* 2^202 - 2^2 */ fsquare(t1,t0);
-  /* 2^250 - 2^50 */ for (i = 2;i < 50;i += 2) { fsquare(t0,t1); fsquare(t1,t0); }
-  /* 2^250 - 2^0 */ fmul(t0,t1,z2_50_0);
-
-  /* 2^251 - 2^1 */ fsquare(t1,t0);
-  /* 2^252 - 2^2 */ fsquare(t0,t1);
-  /* 2^253 - 2^3 */ fsquare(t1,t0);
-  /* 2^254 - 2^4 */ fsquare(t0,t1);
-  /* 2^255 - 2^5 */ fsquare(t1,t0);
-  /* 2^255 - 21 */ fmul(out,t1,z11);
-}
-
-int
-curve25519_donna(u8 *mypublic, const u8 *secret, const u8 *basepoint) {
-  limb bp[10], x[10], z[11], zmone[10];
-  uint8_t e[32];
-  int i;
-
-  for (i = 0; i < 32; ++i) e[i] = secret[i];
-  e[0] &= 248;
-  e[31] &= 127;
-  e[31] |= 64;
-
-  fexpand(bp, basepoint);
-  cmult(x, z, e, bp);
-  crecip(zmone, z);
-  fmul(z, x, zmone);
-  fcontract(mypublic, z);
-  return 0;
-}

curve25519.c

@@ -0,0 +1,497 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "dbrandom.h"
+#include "curve25519.h"
+
+#if DROPBEAR_CURVE25519 || DROPBEAR_ED25519
+
+/* Modified TweetNaCl version 20140427, a self-contained public-domain C library.
+ * https://tweetnacl.cr.yp.to/ */
+
+#define FOR(i,n) for (i = 0;i < n;++i)
+#define sv static void
+
+typedef unsigned char u8;
+typedef unsigned long u32;
+typedef unsigned long long u64;
+typedef long long i64;
+typedef i64 gf[16];
+
+#if DROPBEAR_CURVE25519
+static const gf
+  _121665 = {0xDB41,1};
+#endif /* DROPBEAR_CURVE25519 */
+#if DROPBEAR_ED25519
+static const gf
+  gf0,
+  gf1 = {1},
+  D2 = {0xf159, 0x26b2, 0x9b94, 0xebd6, 0xb156, 0x8283, 0x149a, 0x00e0, 0xd130, 0xeef3, 0x80f2, 0x198e, 0xfce7, 0x56df, 0xd9dc, 0x2406},
+  X = {0xd51a, 0x8f25, 0x2d60, 0xc956, 0xa7b2, 0x9525, 0xc760, 0x692c, 0xdc5c, 0xfdd6, 0xe231, 0xc0a4, 0x53fe, 0xcd6e, 0x36d3, 0x2169},
+  Y = {0x6658, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666, 0x6666};
+#if DROPBEAR_SIGNKEY_VERIFY
+static const gf
+  D = {0x78a3, 0x1359, 0x4dca, 0x75eb, 0xd8ab, 0x4141, 0x0a4d, 0x0070, 0xe898, 0x7779, 0x4079, 0x8cc7, 0xfe73, 0x2b6f, 0x6cee, 0x5203},
+  I = {0xa0b0, 0x4a0e, 0x1b27, 0xc4ee, 0xe478, 0xad2f, 0x1806, 0x2f43, 0xd7a7, 0x3dfb, 0x0099, 0x2b4d, 0xdf0b, 0x4fc1, 0x2480, 0x2b83};
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+#endif /* DROPBEAR_ED25519 */
+
+#if DROPBEAR_ED25519
+#if DROPBEAR_SIGNKEY_VERIFY
+static int vn(const u8 *x,const u8 *y,u32 n)
+{
+  u32 i,d = 0;
+  FOR(i,n) d |= x[i]^y[i];
+  return (1 & ((d - 1) >> 8)) - 1;
+}
+
+static int crypto_verify_32(const u8 *x,const u8 *y)
+{
+  return vn(x,y,32);
+}
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+
+sv set25519(gf r, const gf a)
+{
+  int i;
+  FOR(i,16) r[i]=a[i];
+}
+#endif /* DROPBEAR_ED25519 */
+
+sv car25519(gf o)
+{
+  int i;
+  i64 c;
+  FOR(i,16) {
+    o[i]+=(1LL<<16);
+    c=o[i]>>16;
+    o[(i+1)*(i<15)]+=c-1+37*(c-1)*(i==15);
+    o[i]-=c<<16;
+  }
+}
+
+sv sel25519(gf p,gf q,int b)
+{
+  i64 t,i,c=~(b-1);
+  FOR(i,16) {
+    t= c&(p[i]^q[i]);
+    p[i]^=t;
+    q[i]^=t;
+  }
+}
+
+sv pack25519(u8 *o,const gf n)
+{
+  int i,j,b;
+  gf m,t;
+  FOR(i,16) t[i]=n[i];
+  car25519(t);
+  car25519(t);
+  car25519(t);
+  FOR(j,2) {
+    m[0]=t[0]-0xffed;
+    for(i=1;i<15;i++) {
+      m[i]=t[i]-0xffff-((m[i-1]>>16)&1);
+      m[i-1]&=0xffff;
+    }
+    m[15]=t[15]-0x7fff-((m[14]>>16)&1);
+    b=(m[15]>>16)&1;
+    m[14]&=0xffff;
+    sel25519(t,m,1-b);
+  }
+  FOR(i,16) {
+    o[2*i]=t[i]&0xff;
+    o[2*i+1]=t[i]>>8;
+  }
+}
+
+#if DROPBEAR_ED25519
+#if DROPBEAR_SIGNKEY_VERIFY
+static int neq25519(const gf a, const gf b)
+{
+  u8 c[32],d[32];
+  pack25519(c,a);
+  pack25519(d,b);
+  return crypto_verify_32(c,d);
+}
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+
+static u8 par25519(const gf a)
+{
+  u8 d[32];
+  pack25519(d,a);
+  return d[0]&1;
+}
+#endif /* DROPBEAR_ED25519 */
+
+sv unpack25519(gf o, const u8 *n)
+{
+  int i;
+  FOR(i,16) o[i]=n[2*i]+((i64)n[2*i+1]<<8);
+  o[15]&=0x7fff;
+}
+
+sv A(gf o,const gf a,const gf b)
+{
+  int i;
+  FOR(i,16) o[i]=a[i]+b[i];
+}
+
+sv Z(gf o,const gf a,const gf b)
+{
+  int i;
+  FOR(i,16) o[i]=a[i]-b[i];
+}
+
+sv M(gf o,const gf a,const gf b)
+{
+  i64 i,j,t[31];
+  FOR(i,31) t[i]=0;
+  FOR(i,16) FOR(j,16) t[i+j]+=a[i]*b[j];
+  FOR(i,15) t[i]+=38*t[i+16];
+  FOR(i,16) o[i]=t[i];
+  car25519(o);
+  car25519(o);
+}
+
+sv S(gf o,const gf a)
+{
+  M(o,a,a);
+}
+
+sv inv25519(gf o,const gf i)
+{
+  gf c;
+  int a;
+  FOR(a,16) c[a]=i[a];
+  for(a=253;a>=0;a--) {
+    S(c,c);
+    if(a!=2&&a!=4) M(c,c,i);
+  }
+  FOR(a,16) o[a]=c[a];
+}
+
+#if DROPBEAR_ED25519 && DROPBEAR_SIGNKEY_VERIFY
+sv pow2523(gf o,const gf i)
+{
+  gf c;
+  int a;
+  FOR(a,16) c[a]=i[a];
+  for(a=250;a>=0;a--) {
+    S(c,c);
+    if(a!=1) M(c,c,i);
+  }
+  FOR(a,16) o[a]=c[a];
+}
+#endif /* DROPBEAR_ED25519 && DROPBEAR_SIGNKEY_VERIFY */
+
+#if DROPBEAR_CURVE25519
+void dropbear_curve25519_scalarmult(u8 *q,const u8 *n,const u8 *p)
+{
+  u8 z[32];
+  i64 x[80],r,i;
+  gf a,b,c,d,e,f;
+  FOR(i,31) z[i]=n[i];
+  z[31]=(n[31]&127)|64;
+  z[0]&=248;
+  unpack25519(x,p);
+  FOR(i,16) {
+    b[i]=x[i];
+    d[i]=a[i]=c[i]=0;
+  }
+  a[0]=d[0]=1;
+  for(i=254;i>=0;--i) {
+    r=(z[i>>3]>>(i&7))&1;
+    sel25519(a,b,r);
+    sel25519(c,d,r);
+    A(e,a,c);
+    Z(a,a,c);
+    A(c,b,d);
+    Z(b,b,d);
+    S(d,e);
+    S(f,a);
+    M(a,c,a);
+    M(c,b,e);
+    A(e,a,c);
+    Z(a,a,c);
+    S(b,a);
+    Z(c,d,f);
+    M(a,c,_121665);
+    A(a,a,d);
+    M(c,c,a);
+    M(a,d,f);
+    M(d,b,x);
+    S(b,e);
+    sel25519(a,b,r);
+    sel25519(c,d,r);
+  }
+  FOR(i,16) {
+    x[i+16]=a[i];
+    x[i+32]=c[i];
+    x[i+48]=b[i];
+    x[i+64]=d[i];
+  }
+  inv25519(x+32,x+32);
+  M(x+16,x+16,x+32);
+  pack25519(q,x+16);
+}
+#endif /* DROPBEAR_CURVE25519 */
+
+#if DROPBEAR_ED25519
+static int crypto_hash(u8 *out,const u8 *m,u64 n)
+{
+  hash_state hs;
+
+  sha512_init(&hs);
+  sha512_process(&hs, m, n);
+  return sha512_done(&hs, out);
+}
+
+sv add(gf p[4],gf q[4])
+{
+  gf a,b,c,d,t,e,f,g,h;
+  
+  Z(a, p[1], p[0]);
+  Z(t, q[1], q[0]);
+  M(a, a, t);
+  A(b, p[0], p[1]);
+  A(t, q[0], q[1]);
+  M(b, b, t);
+  M(c, p[3], q[3]);
+  M(c, c, D2);
+  M(d, p[2], q[2]);
+  A(d, d, d);
+  Z(e, b, a);
+  Z(f, d, c);
+  A(g, d, c);
+  A(h, b, a);
+
+  M(p[0], e, f);
+  M(p[1], h, g);
+  M(p[2], g, f);
+  M(p[3], e, h);
+}
+
+sv cswap(gf p[4],gf q[4],u8 b)
+{
+  int i;
+  FOR(i,4)
+    sel25519(p[i],q[i],b);
+}
+
+sv pack(u8 *r,gf p[4])
+{
+  gf tx, ty, zi;
+  inv25519(zi, p[2]); 
+  M(tx, p[0], zi);
+  M(ty, p[1], zi);
+  pack25519(r, ty);
+  r[31] ^= par25519(tx) << 7;
+}
+
+sv scalarmult(gf p[4],gf q[4],const u8 *s)
+{
+  int i;
+  set25519(p[0],gf0);
+  set25519(p[1],gf1);
+  set25519(p[2],gf1);
+  set25519(p[3],gf0);
+  for (i = 255;i >= 0;--i) {
+    u8 b = (s[i/8]>>(i&7))&1;
+    cswap(p,q,b);
+    add(q,p);
+    add(p,p);
+    cswap(p,q,b);
+  }
+}
+
+sv scalarbase(gf p[4],const u8 *s)
+{
+  gf q[4];
+  set25519(q[0],X);
+  set25519(q[1],Y);
+  set25519(q[2],gf1);
+  M(q[3],X,Y);
+  scalarmult(p,q,s);
+}
+
+void dropbear_ed25519_make_key(u8 *pk,u8 *sk)
+{
+  u8 d[64];
+  gf p[4];
+
+  genrandom(sk, 32);
+
+  crypto_hash(d, sk, 32);
+  d[0] &= 248;
+  d[31] &= 127;
+  d[31] |= 64;
+
+  scalarbase(p,d);
+  pack(pk,p);
+}
+
+static const u64 L[32] = {0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7, 0xa2, 0xde, 0xf9, 0xde, 0x14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x10};
+
+sv modL(u8 *r,i64 x[64])
+{
+  i64 carry,i,j;
+  for (i = 63;i >= 32;--i) {
+    carry = 0;
+    for (j = i - 32;j < i - 12;++j) {
+      x[j] += carry - 16 * x[i] * L[j - (i - 32)];
+      carry = (x[j] + 128) >> 8;
+      x[j] -= carry << 8;
+    }
+    x[j] += carry;
+    x[i] = 0;
+  }
+  carry = 0;
+  FOR(j,32) {
+    x[j] += carry - (x[31] >> 4) * L[j];
+    carry = x[j] >> 8;
+    x[j] &= 255;
+  }
+  FOR(j,32) x[j] -= carry * L[j];
+  FOR(i,32) {
+    x[i+1] += x[i] >> 8;
+    r[i] = x[i] & 255;
+  }
+}
+
+sv reduce(u8 *r)
+{
+  i64 x[64],i;
+  FOR(i,64) x[i] = (u64) r[i];
+  FOR(i,64) r[i] = 0;
+  modL(r,x);
+}
+
+void dropbear_ed25519_sign(const u8 *m,u32 mlen,u8 *s,u32 *slen,const u8 *sk, const u8 *pk)
+{
+  hash_state hs;
+  u8 d[64],h[64],r[64];
+  i64 x[64];
+  gf p[4];
+  u32 i,j;
+
+  crypto_hash(d, sk, 32);
+  d[0] &= 248;
+  d[31] &= 127;
+  d[31] |= 64;
+
+  *slen = 64;
+
+  sha512_init(&hs);
+  sha512_process(&hs,d + 32,32);
+  sha512_process(&hs,m,mlen);
+  sha512_done(&hs,r);
+  reduce(r);
+  scalarbase(p,r);
+  pack(s,p);
+
+  sha512_init(&hs);
+  sha512_process(&hs,s,32);
+  sha512_process(&hs,pk,32);
+  sha512_process(&hs,m,mlen);
+  sha512_done(&hs,h);
+  reduce(h);
+
+  FOR(i,64) x[i] = 0;
+  FOR(i,32) x[i] = (u64) r[i];
+  FOR(i,32) FOR(j,32) x[i+j] += h[i] * (u64) d[j];
+  modL(s + 32,x);
+}
+
+#if DROPBEAR_SIGNKEY_VERIFY
+static int unpackneg(gf r[4],const u8 p[32])
+{
+  gf t, chk, num, den, den2, den4, den6;
+  set25519(r[2],gf1);
+  unpack25519(r[1],p);
+  S(num,r[1]);
+  M(den,num,D);
+  Z(num,num,r[2]);
+  A(den,r[2],den);
+
+  S(den2,den);
+  S(den4,den2);
+  M(den6,den4,den2);
+  M(t,den6,num);
+  M(t,t,den);
+
+  pow2523(t,t);
+  M(t,t,num);
+  M(t,t,den);
+  M(t,t,den);
+  M(r[0],t,den);
+
+  S(chk,r[0]);
+  M(chk,chk,den);
+  if (neq25519(chk, num)) M(r[0],r[0],I);
+
+  S(chk,r[0]);
+  M(chk,chk,den);
+  if (neq25519(chk, num)) return -1;
+
+  if (par25519(r[0]) == (p[31]>>7)) Z(r[0],gf0,r[0]);
+
+  M(r[3],r[0],r[1]);
+  return 0;
+}
+
+int dropbear_ed25519_verify(const u8 *m,u32 mlen,const u8 *s,u32 slen,const u8 *pk)
+{
+  hash_state hs;
+  u8 t[32],h[64];
+  gf p[4],q[4];
+
+  if (slen < 64) return -1;
+
+  if (unpackneg(q,pk)) return -1;
+
+  sha512_init(&hs);
+  sha512_process(&hs,s,32);
+  sha512_process(&hs,pk,32);
+  sha512_process(&hs,m,mlen);
+  sha512_done(&hs,h);
+
+  reduce(h);
+  scalarmult(p,q,h);
+
+  scalarbase(q,s + 32);
+  add(p,q);
+  pack(t,p);
+
+  if (crypto_verify_32(s, t))
+    return -1;
+
+  return 0;
+}
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+
+#endif /* DROPBEAR_ED25519 */
+
+#endif /* DROPBEAR_CURVE25519 || DROPBEAR_ED25519 */

curve25519.h

@@ -0,0 +1,37 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#ifndef DROPBEAR_CURVE25519_H
+#define DROPBEAR_CURVE25519_H
+
+void dropbear_curve25519_scalarmult(unsigned char *q, const unsigned char *n, const unsigned char *p);
+void dropbear_ed25519_make_key(unsigned char *pk, unsigned char  *sk);
+void dropbear_ed25519_sign(const unsigned char *m, unsigned long mlen,
+			  unsigned char *s, unsigned long *slen,
+			  const unsigned char *sk, const unsigned char *pk);
+int dropbear_ed25519_verify(const unsigned char *m, unsigned long mlen,
+			    const unsigned char *s, unsigned long slen,
+			    const unsigned char *pk);
+
+#endif /* DROPBEAR_CURVE25519_H */

dbclient.1

@@ -19,7 +19,7 @@ dbclient \- lightweight SSH client
 
 .SH DESCRIPTION
 .B dbclient
-is a small SSH client 
+is the client part of Dropbear SSH
 .SH OPTIONS
 .TP
 .TP
@@ -44,27 +44,27 @@ from OpenSSH with dropbearconvert(1). The default path ~/.ssh/id_dropbear is use
 .TP
 .B \-L\fR [\fIlistenaddress\fR]:\fIlistenport\fR:\fIhost\fR:\fIport\fR
 Local port forwarding.
-Forward the port
+Forward 
 .I listenport
-on the local host through the SSH connection to port
+on the local host through the SSH connection to 
 .I port
-on the host
+on 
 .IR host .
 .TP
 .B \-R\fR [\fIlistenaddress\fR]:\fIlistenport\fR:\fIhost\fR:\fIport\fR
 Remote port forwarding.
-Forward the port
+Forward 
 .I listenport
-on the remote host through the SSH connection to port
+on the remote host through the SSH connection to 
 .I port
-on the host
+on 
 .IR host .
 .TP
 .B \-l \fIuser
 Username.
 Login as
 .I user
-on the remote host.
+on the remote host. An alternative is to specify user@host.
 .TP
 .B \-t
 Allocate a PTY. This is the default when no command is given, it gives a full
@@ -72,7 +72,7 @@ interactive remote session. The main effect is that keystrokes are sent remotely
 immediately as opposed to local line-based editing.
 .TP
 .B \-T
-Don't allocate a PTY. This is the default a command is given. See -t.
+Don't allocate a PTY. This is the default when a command is given. See -t.
 .TP
 .B \-N
 Don't request a remote shell or run any commands. Any command arguments are ignored.
@@ -149,10 +149,13 @@ The following options have currently been implemented:
 .RS
 .TP
 .B ExitOnForwardFailure
-Specifies whether dbclient should terminate the connection if it cannot set up all requested local and remote port forwardings. The argument must be “yes” or “no”.  The default is “no”.
+Specifies whether dbclient should terminate the connection if it cannot set up all requested local and remote port forwardings. The argument must be "yes" or "no".  The default is "no".
 .TP
 .B UseSyslog
 Send dbclient log messages to syslog in addition to stderr.
+.TP
+.B Port
+Specify a listening port, like the \fI-p\fR argument.
 .RE
 .TP
 .B \-s 

dbhelpers.c

@@ -9,16 +9,9 @@ void m_burn(void *data, unsigned int len) {
 #elif defined(HAVE_EXPLICIT_BZERO)
 	explicit_bzero(data, len);
 #else
-/* Based on the method in David Wheeler's
- * "Secure Programming for Linux and Unix HOWTO". May not be safe
- * against link-time optimisation. */
-	volatile char *p = data;
-
-	if (data == NULL)
-		return;
-	while (len--) {
-		*p++ = 0x0;
-	}
+	/* This must be volatile to avoid compiler optimisation */
+	volatile void *p = data;
+	memset((void*)p, 0x0, len);
 #endif
 }
 

dbmalloc.c

@@ -0,0 +1,192 @@
+#include "dbmalloc.h"
+#include "dbutil.h"
+
+
+void * m_calloc(size_t nmemb, size_t size) {
+    if (SIZE_T_MAX / nmemb < size) {
+        dropbear_exit("m_calloc failed");
+    }
+    return m_malloc(nmemb*size);
+}
+
+void * m_strdup(const char * str) {
+    char* ret;
+    unsigned int len;
+    len = strlen(str);
+
+    ret = m_malloc(len+1);
+    if (ret == NULL) {
+        dropbear_exit("m_strdup failed");
+    }
+    memcpy(ret, str, len+1);
+    return ret;
+}
+
+#if !DROPBEAR_TRACKING_MALLOC
+
+/* Simple wrappers around malloc etc */
+void * m_malloc(size_t size) {
+
+	void* ret;
+
+	if (size == 0) {
+		dropbear_exit("m_malloc failed");
+	}
+	ret = calloc(1, size);
+	if (ret == NULL) {
+		dropbear_exit("m_malloc failed");
+	}
+	return ret;
+
+}
+
+void * m_realloc(void* ptr, size_t size) {
+
+	void *ret;
+
+	if (size == 0) {
+		dropbear_exit("m_realloc failed");
+	}
+	ret = realloc(ptr, size);
+	if (ret == NULL) {
+		dropbear_exit("m_realloc failed");
+	}
+	return ret;
+}
+
+
+#else
+
+/* For fuzzing */
+
+struct dbmalloc_header {
+    unsigned int epoch;
+    struct dbmalloc_header *prev;
+    struct dbmalloc_header *next;
+};
+
+static void put_alloc(struct dbmalloc_header *header);
+static void remove_alloc(struct dbmalloc_header *header);
+
+/* end of the linked list */
+static struct dbmalloc_header* staple;
+
+unsigned int current_epoch = 0;
+
+void m_malloc_set_epoch(unsigned int epoch) {
+    current_epoch = epoch;
+}
+
+void m_malloc_free_epoch(unsigned int epoch, int dofree) {
+    struct dbmalloc_header* header;
+    struct dbmalloc_header* nextheader = NULL;
+    struct dbmalloc_header* oldstaple = staple;
+    staple = NULL;
+    /* free allocations from this epoch, create a new staple-anchored list from
+    the remainder */
+    for (header = oldstaple; header; header = nextheader)
+    {
+        nextheader = header->next;
+        if (header->epoch == epoch) {
+            if (dofree) {
+                free(header);
+            }
+        } else {
+            header->prev = NULL;
+            header->next = NULL;
+            put_alloc(header);
+        }
+    }
+}
+
+static void put_alloc(struct dbmalloc_header *header) {
+    assert(header->next == NULL);
+    assert(header->prev == NULL);
+    if (staple) {
+        staple->prev = header;
+    }
+    header->next = staple;
+    staple = header;
+}
+
+static void remove_alloc(struct dbmalloc_header *header) {
+    if (header->prev) {
+        header->prev->next = header->next;
+    }
+    if (header->next) {
+        header->next->prev = header->prev;
+    }
+    if (staple == header) {
+        staple = header->next;
+    }
+    header->prev = NULL;
+    header->next = NULL;
+}
+
+static struct dbmalloc_header* get_header(void* ptr) {
+    char* bptr = ptr;
+    return (struct dbmalloc_header*)&bptr[-sizeof(struct dbmalloc_header)];
+}
+
+void * m_malloc(size_t size) {
+    char* mem = NULL;
+    struct dbmalloc_header* header = NULL;
+
+    if (size == 0 || size > 1e9) {
+        dropbear_exit("m_malloc failed");
+    }
+
+    size = size + sizeof(struct dbmalloc_header);
+
+    mem = calloc(1, size);
+    if (mem == NULL) {
+        dropbear_exit("m_malloc failed");
+    }
+    header = (struct dbmalloc_header*)mem;
+    put_alloc(header);
+    header->epoch = current_epoch;
+    return &mem[sizeof(struct dbmalloc_header)];
+}
+
+void * m_realloc(void* ptr, size_t size) {
+    char* mem = NULL;
+    struct dbmalloc_header* header = NULL;
+    if (size == 0 || size > 1e9) {
+        dropbear_exit("m_realloc failed");
+    }
+
+    header = get_header(ptr);
+    remove_alloc(header);
+
+    size = size + sizeof(struct dbmalloc_header);
+    mem = realloc(header, size);
+    if (mem == NULL) {
+        dropbear_exit("m_realloc failed");
+    }
+
+    header = (struct dbmalloc_header*)mem;
+    put_alloc(header);
+    return &mem[sizeof(struct dbmalloc_header)];
+}
+
+void m_free_direct(void* ptr) {
+    struct dbmalloc_header* header = NULL;
+    if (!ptr) {
+        return;
+    }
+    header = get_header(ptr);
+    remove_alloc(header);
+    free(header);
+}
+
+#endif /* DROPBEAR_TRACKING_MALLOC */
+
+void * m_realloc_ltm(void* ptr, size_t oldsize, size_t newsize) {
+   (void)oldsize;
+   return m_realloc(ptr, newsize);
+}
+
+void m_free_ltm(void *mem, size_t size) {
+   (void)size;
+   m_free_direct(mem);
+}

dbmalloc.h

@@ -0,0 +1,27 @@
+#ifndef DBMALLOC_H_
+#define DBMALLOC_H_
+
+#include "options.h"
+#include <stdint.h>
+#include <stdlib.h>
+
+void * m_malloc(size_t size);
+void * m_calloc(size_t nmemb, size_t size);
+void * m_strdup(const char * str);
+void * m_realloc(void* ptr, size_t size);
+
+#if DROPBEAR_TRACKING_MALLOC
+void m_free_direct(void* ptr);
+void m_malloc_set_epoch(unsigned int epoch);
+void m_malloc_free_epoch(unsigned int epoch, int dofree);
+
+#else
+/* plain wrapper */
+#define m_free_direct free
+
+#endif
+
+#define m_free(X) do {m_free_direct(X); (X) = NULL;} while (0)
+
+
+#endif /* DBMALLOC_H_ */

dbrandom.c

@@ -27,7 +27,7 @@
 #include "dbutil.h"
 #include "bignum.h"
 #include "dbrandom.h"
-
+#include "runopts.h"
 
 /* this is used to generate unique output from the same hashpool */
 static uint32_t counter = 0;
@@ -49,24 +49,19 @@ static int donerandinit = 0;
  *
  */
 
-/* Pass len=0 to hash an entire file */
+/* Pass wantlen=0 to hash an entire file */
 static int
 process_file(hash_state *hs, const char *filename,
-		unsigned int len, int prngd)
-{
-	static int already_blocked = 0;
-	int readfd;
+		unsigned int wantlen, int prngd) {
+	int readfd = -1;
 	unsigned int readcount;
 	int ret = DROPBEAR_FAILURE;
 
+	if (prngd) {
 #if DROPBEAR_USE_PRNGD
-	if (prngd)
-	{
 		readfd = connect_unix(filename);
-	}
-	else
 #endif
-	{
+	} else {
 		readfd = open(filename, O_RDONLY);
 	}
 
@@ -75,58 +70,31 @@ process_file(hash_state *hs, const char *filename,
 	}
 
 	readcount = 0;
-	while (len == 0 || readcount < len)
-	{
+	while (wantlen == 0 || readcount < wantlen) {
 		int readlen, wantread;
 		unsigned char readbuf[4096];
-		if (!already_blocked && !prngd)
-		{
-			int res;
-			struct timeval timeout;
-			fd_set read_fds;
-
- 			timeout.tv_sec  = 2;
- 			timeout.tv_usec = 0;
-
-			FD_ZERO(&read_fds);
-			FD_SET(readfd, &read_fds);
-			res = select(readfd + 1, &read_fds, NULL, NULL, &timeout);
-			if (res == 0)
-			{
-				dropbear_log(LOG_WARNING, "Warning: Reading the randomness source '%s' seems to have blocked.\nYou may need to find a better entropy source.", filename);
-				already_blocked = 1;
-			}
-		}
-
-		if (len == 0)
-		{
+		if (wantlen == 0) {
 			wantread = sizeof(readbuf);
-		} 
-		else
-		{
-			wantread = MIN(sizeof(readbuf), len-readcount);
+		} else {
+			wantread = MIN(sizeof(readbuf), wantlen-readcount);
 		}
 
 #if DROPBEAR_USE_PRNGD
-		if (prngd)
-		{
+		if (prngd) {
 			char egdcmd[2];
 			egdcmd[0] = 0x02;	/* blocking read */
 			egdcmd[1] = (unsigned char)wantread;
-			if (write(readfd, egdcmd, 2) < 0)
-			{
+			if (write(readfd, egdcmd, 2) < 0) {
 				dropbear_exit("Can't send command to egd");
 			}
 		}
 #endif
-
 		readlen = read(readfd, readbuf, wantread);
 		if (readlen <= 0) {
 			if (readlen < 0 && errno == EINTR) {
 				continue;
 			}
-			if (readlen == 0 && len == 0)
-			{
+			if (readlen == 0 && wantlen == 0) {
 				/* whole file was read as requested */
 				break;
 			}
@@ -145,6 +113,12 @@ void addrandom(const unsigned char * buf, unsigned int len)
 {
 	hash_state hs;
 
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return;
+	}
+#endif
+
 	/* hash in the new seed data */
 	sha1_init(&hs);
 	/* existing state (zeroes on startup) */
@@ -157,6 +131,11 @@ void addrandom(const unsigned char * buf, unsigned int len)
 
 static void write_urandom()
 {
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return;
+	}
+#endif
 #if !DROPBEAR_USE_PRNGD
 	/* This is opportunistic, don't worry about failure */
 	unsigned char buf[INIT_SEED_SIZE];
@@ -170,6 +149,75 @@ static void write_urandom()
 #endif
 }
 
+#if DROPBEAR_FUZZ
+void fuzz_seed(const unsigned char* dat, unsigned int len) {
+	hash_state hs;
+	sha1_init(&hs);
+	sha1_process(&hs, "fuzzfuzzfuzz", strlen("fuzzfuzzfuzz"));
+	sha1_process(&hs, dat, len);
+	sha1_done(&hs, hashpool);
+	counter = 0;
+	donerandinit = 1;
+}
+#endif
+
+
+#ifdef HAVE_GETRANDOM
+/* Reads entropy seed with getrandom(). 
+ * May block if the kernel isn't ready.
+ * Return DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+static int process_getrandom(hash_state *hs) {
+	char buf[INIT_SEED_SIZE];
+	ssize_t ret;
+
+	/* First try non-blocking so that we can warn about waiting */
+	ret = getrandom(buf, sizeof(buf), GRND_NONBLOCK);
+	if (ret == -1) {
+		if (errno == ENOSYS) {
+			/* Old kernel */
+			return DROPBEAR_FAILURE;
+		}
+		/* Other errors fall through to blocking getrandom() */
+		TRACE(("first getrandom() failed: %d %s", errno, strerror(errno)))
+		if (errno == EAGAIN) {
+			dropbear_log(LOG_WARNING, "Waiting for kernel randomness to be initialised...");
+		}
+	}
+
+	/* Wait blocking if needed. Loop in case we get EINTR */
+	while (ret != sizeof(buf)) {
+		ret = getrandom(buf, sizeof(buf), 0);
+
+		if (ret == sizeof(buf)) {
+			/* Success */
+			break;
+		}
+		if (ret == -1 && errno == EINTR) {
+			/* Try again. */
+			continue;
+		}
+		if (ret >= 0) {
+			TRACE(("Short read %zd from getrandom() shouldn't happen", ret))
+			/* Try again? */
+			continue;
+		}
+
+		/* Unexpected problem, fall back to /dev/urandom */
+		TRACE(("2nd getrandom() failed: %d %s", errno, strerror(errno)))
+		break;
+	}
+
+	if (ret == sizeof(buf)) {
+		/* Success, stir in the entropy */
+		sha1_process(hs, (void*)buf, sizeof(buf));
+		return DROPBEAR_SUCCESS;
+	}
+
+	return DROPBEAR_FAILURE;
+
+}
+#endif /* HAVE_GETRANDOM */
+
 /* Initialise the prng from /dev/urandom or prngd. This function can
  * be called multiple times */
 void seedrandom() {
@@ -179,27 +227,45 @@ void seedrandom() {
 	pid_t pid;
 	struct timeval tv;
 	clock_t clockval;
+	int urandom_seeded = 0;
+
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return;
+	}
+#endif
 
 	/* hash in the new seed data */
 	sha1_init(&hs);
+
 	/* existing state */
 	sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
 
-#if DROPBEAR_USE_PRNGD
-	if (process_file(&hs, DROPBEAR_PRNGD_SOCKET, INIT_SEED_SIZE, 1) 
-			!= DROPBEAR_SUCCESS) {
-		dropbear_exit("Failure reading random device %s", 
-				DROPBEAR_PRNGD_SOCKET);
-	}
-#else
-	/* non-blocking random source (probably /dev/urandom) */
-	if (process_file(&hs, DROPBEAR_URANDOM_DEV, INIT_SEED_SIZE, 0) 
-			!= DROPBEAR_SUCCESS) {
-		dropbear_exit("Failure reading random device %s", 
-				DROPBEAR_URANDOM_DEV);
+#ifdef HAVE_GETRANDOM
+	if (process_getrandom(&hs) == DROPBEAR_SUCCESS) {
+		urandom_seeded = 1;
 	}
 #endif
 
+	if (!urandom_seeded) {
+#if DROPBEAR_USE_PRNGD
+		if (process_file(&hs, DROPBEAR_PRNGD_SOCKET, INIT_SEED_SIZE, 1) 
+				!= DROPBEAR_SUCCESS) {
+			dropbear_exit("Failure reading random device %s", 
+					DROPBEAR_PRNGD_SOCKET);
+			urandom_seeded = 1;
+		}
+#else
+		/* non-blocking random source (probably /dev/urandom) */
+		if (process_file(&hs, DROPBEAR_URANDOM_DEV, INIT_SEED_SIZE, 0) 
+				!= DROPBEAR_SUCCESS) {
+			dropbear_exit("Failure reading random device %s", 
+					DROPBEAR_URANDOM_DEV);
+			urandom_seeded = 1;
+		}
+#endif
+	} /* urandom_seeded */
+
 	/* A few other sources to fall back on. 
 	 * Add more here for other platforms */
 #ifdef __linux__

dbutil.c

@@ -120,6 +120,12 @@ static void generic_dropbear_exit(int exitcode, const char* format,
 
 	_dropbear_log(LOG_INFO, fmtbuf, param);
 
+#if DROPBEAR_FUZZ
+    if (fuzz.do_jmp) {
+        longjmp(fuzz.jmp, 1);
+    }
+#endif
+
 	exit(exitcode);
 }
 
@@ -251,6 +257,12 @@ int spawn_command(void(*exec_fn)(const void *user_data), const void *exec_data,
 	const int FDIN = 0;
 	const int FDOUT = 1;
 
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return fuzz_spawn_command(ret_writefd, ret_readfd, ret_errfd, ret_pid);
+	}
+#endif
+
 	/* redirect stdin/stdout/stderr */
 	if (pipe(infds) != 0) {
 		return DROPBEAR_FAILURE;
@@ -373,25 +385,43 @@ void run_shell_command(const char* cmd, unsigned int maxfd, char* usershell) {
 
 #if DEBUG_TRACE
 void printhex(const char * label, const unsigned char * buf, int len) {
-
-	int i;
+	int i, j;
 
 	fprintf(stderr, "%s\n", label);
-	for (i = 0; i < len; i++) {
-		fprintf(stderr, "%02x", buf[i]);
-		if (i % 16 == 15) {
-			fprintf(stderr, "\n");
+	/* for each 16 byte line */
+	for (j = 0; j < len; j += 16) {
+		const int linelen = MIN(16, len - j);
+
+		/* print hex digits */
+		for (i = 0; i < 16; i++) {
+			if (i < linelen) {
+				fprintf(stderr, "%02x", buf[j+i]);
+			} else {
+				fprintf(stderr, "  ");
+			}
+			// separator between pairs
+			if (i % 2 ==1) {
+				fprintf(stderr, " ");
+			}
 		}
-		else if (i % 2 == 1) {
-			fprintf(stderr, " ");
+
+		/* print characters */
+		fprintf(stderr, "  ");
+		for (i = 0; i < linelen; i++) {
+			char c = buf[j+i];
+			if (!isprint(c)) {
+				c = '.';
+			}
+			fputc(c, stderr);
 		}
+		fprintf(stderr, "\n");
 	}
-	fprintf(stderr, "\n");
 }
 
 void printmpint(const char *label, mp_int *mp) {
 	buffer *buf = buf_new(1000);
 	buf_putmpint(buf, mp);
+	fprintf(stderr, "%d bits ", mp_count_bits(mp));
 	printhex(label, buf->data, buf->len);
 	buf_free(buf);
 
@@ -520,57 +550,26 @@ void m_close(int fd) {
 	}
 }
 	
-void * m_malloc(size_t size) {
-
-	void* ret;
-
-	if (size == 0) {
-		dropbear_exit("m_malloc failed");
-	}
-	ret = calloc(1, size);
-	if (ret == NULL) {
-		dropbear_exit("m_malloc failed");
-	}
-	return ret;
-
-}
-
-void * m_strdup(const char * str) {
-	char* ret;
-
-	ret = strdup(str);
-	if (ret == NULL) {
-		dropbear_exit("m_strdup failed");
-	}
-	return ret;
-}
-
-void * m_realloc(void* ptr, size_t size) {
-
-	void *ret;
-
-	if (size == 0) {
-		dropbear_exit("m_realloc failed");
-	}
-	ret = realloc(ptr, size);
-	if (ret == NULL) {
-		dropbear_exit("m_realloc failed");
-	}
-	return ret;
-}
-
 void setnonblocking(int fd) {
 
 	TRACE(("setnonblocking: %d", fd))
 
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return;
+	}
+#endif
+
 	if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) {
 		if (errno == ENODEV) {
 			/* Some devices (like /dev/null redirected in)
 			 * can't be set to non-blocking */
 			TRACE(("ignoring ENODEV for setnonblocking"))
 		} else {
+		{
 			dropbear_exit("Couldn't set nonblocking");
 		}
+		}
 	}
 	TRACE(("leave setnonblocking"))
 }
@@ -584,8 +583,15 @@ void disallow_core() {
 /* Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE, with the result in *val */
 int m_str_to_uint(const char* str, unsigned int *val) {
 	unsigned long l;
-	errno = 0;
-	l = strtoul(str, NULL, 10);
+	char *endp;
+
+	l = strtoul(str, &endp, 10);
+
+	if (endp == str || *endp != '\0') {
+		// parse error
+		return DROPBEAR_FAILURE;
+	}
+
 	/* The c99 spec doesn't actually seem to define EINVAL, but most platforms
 	 * I've looked at mention it in their manpage */
 	if ((l == 0 && errno == EINVAL)
@@ -603,11 +609,19 @@ otherwise home directory is prepended */
 char * expand_homedir_path(const char *inpath) {
 	struct passwd *pw = NULL;
 	if (inpath[0] != '/') {
-		pw = getpwuid(getuid());
-		if (pw && pw->pw_dir) {
-			int len = strlen(inpath) + strlen(pw->pw_dir) + 2;
+		char *homedir = getenv("HOME");
+
+		if (!homedir) {
+			pw = getpwuid(getuid());
+			if (pw) {
+				homedir = pw->pw_dir;
+			}
+		}
+
+		if (homedir) {
+			int len = strlen(inpath) + strlen(homedir) + 2;
 			char *buf = m_malloc(len);
-			snprintf(buf, len, "%s/%s", pw->pw_dir, inpath);
+			snprintf(buf, len, "%s/%s", homedir, inpath);
 			return buf;
 		}
 	}
@@ -628,61 +642,67 @@ int constant_time_memcmp(const void* a, const void *b, size_t n)
 	return c;
 }
 
-#if defined(__linux__) && defined(SYS_clock_gettime)
-/* CLOCK_MONOTONIC_COARSE was added in Linux 2.6.32 but took a while to
-reach userspace include headers */
-#ifndef CLOCK_MONOTONIC_COARSE
-#define CLOCK_MONOTONIC_COARSE 6
+/* higher-resolution monotonic timestamp, falls back to gettimeofday */
+void gettime_wrapper(struct timespec *now) {
+	struct timeval tv;
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		/* time stands still when fuzzing */
+		now->tv_sec = 5;
+		now->tv_nsec = 0;
+	}
 #endif
-/* Some old toolchains know SYS_clock_gettime but not CLOCK_MONOTONIC */
-#ifndef CLOCK_MONOTONIC
-#define CLOCK_MONOTONIC 1
+
+#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_MONOTONIC)
+	/* POSIX monotonic clock. Newer Linux, BSD, MacOSX >10.12 */
+	if (clock_gettime(CLOCK_MONOTONIC, now) == 0) {
+		return;
+	}
 #endif
-static clockid_t get_linux_clock_source() {
-	struct timespec ts;
-	if (syscall(SYS_clock_gettime, CLOCK_MONOTONIC_COARSE, &ts) == 0) {
-		return CLOCK_MONOTONIC_COARSE;
-	}
 
-	if (syscall(SYS_clock_gettime, CLOCK_MONOTONIC, &ts) == 0) {
-		return CLOCK_MONOTONIC;
-	}
-	return -1;
-}
-#endif 
-
-time_t monotonic_now() {
 #if defined(__linux__) && defined(SYS_clock_gettime)
-	static clockid_t clock_source = -2;
-
-	if (clock_source == -2) {
-		/* First run, find out which one works. 
-		-1 will fall back to time() */
-		clock_source = get_linux_clock_source();
-	}
-
-	if (clock_source >= 0) {
-		struct timespec ts;
-		if (syscall(SYS_clock_gettime, clock_source, &ts) != 0) {
-			/* Intermittent clock failures should not happen */
-			dropbear_exit("Clock broke");
+	{
+	/* Old linux toolchain - kernel might support it but not the build headers */
+	/* Also glibc <2.17 requires -lrt which we neglect to add */
+	static int linux_monotonic_failed = 0;
+	if (!linux_monotonic_failed) {
+		/* CLOCK_MONOTONIC isn't in some headers */
+		int clock_source_monotonic = 1; 
+		if (syscall(SYS_clock_gettime, clock_source_monotonic, now) == 0) {
+			return;
+		} else {
+			/* Don't try again */
+			linux_monotonic_failed = 1;
 		}
-		return ts.tv_sec;
 	}
-#endif /* linux clock_gettime */
+	}
+#endif /* linux fallback clock_gettime */
 
 #if defined(HAVE_MACH_ABSOLUTE_TIME)
-	/* OS X, see https://developer.apple.com/library/mac/qa/qa1398/_index.html */
+	{
+	/* OS X pre 10.12, see https://developer.apple.com/library/mac/qa/qa1398/_index.html */
 	static mach_timebase_info_data_t timebase_info;
+	uint64_t scaled_time;
 	if (timebase_info.denom == 0) {
 		mach_timebase_info(&timebase_info);
 	}
-	return mach_absolute_time() * timebase_info.numer / timebase_info.denom
-		/ 1e9;
+	scaled_time = mach_absolute_time() * timebase_info.numer / timebase_info.denom;
+	now->tv_sec = scaled_time / 1000000000;
+	now->tv_nsec = scaled_time % 1000000000;
+	}
 #endif /* osx mach_absolute_time */
 
 	/* Fallback for everything else - this will sometimes go backwards */
-	return time(NULL);
+	gettimeofday(&tv, NULL);
+	now->tv_sec = tv.tv_sec;
+	now->tv_nsec = 1000*tv.tv_usec;
+}
+
+/* second-resolution monotonic timestamp */
+time_t monotonic_now() {
+	struct timespec ts;
+	gettime_wrapper(&ts);
+	return ts.tv_sec;
 }
 
 void fsync_parent_dir(const char* fn) {
@@ -700,6 +720,25 @@ void fsync_parent_dir(const char* fn) {
 		TRACE(("error opening directory %s for fsync: %s", dir, strerror(errno)))
 	}
 
-	free(fn_dir);
+	m_free(fn_dir);
 #endif
 }
+
+int fd_read_pending(int fd) {
+	fd_set fds;
+	struct timeval timeout;
+
+	DROPBEAR_FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+	while (1) {
+		timeout.tv_sec = 0;
+		timeout.tv_usec = 0;
+		if (select(fd+1, &fds, NULL, NULL, &timeout) < 0) {
+			if (errno == EINTR) {
+				continue;
+			}
+			return 0;
+		}
+		return FD_ISSET(fd, &fds);
+	}
+}

dbutil.h

@@ -30,6 +30,7 @@
 #include "buffer.h"
 #include "queue.h"
 #include "dbhelpers.h"
+#include "dbmalloc.h"
 
 #ifndef DISABLE_SYSLOG
 void startsyslog(const char *ident);
@@ -66,10 +67,6 @@ int buf_readfile(buffer* buf, const char* filename);
 int buf_getline(buffer * line, FILE * authfile);
 
 void m_close(int fd);
-void * m_malloc(size_t size);
-void * m_strdup(const char * str);
-void * m_realloc(void* ptr, size_t size);
-#define m_free(X) do {free(X); (X) = NULL;} while (0)
 void setnonblocking(int fd);
 void disallow_core(void);
 int m_str_to_uint(const char* str, unsigned int *val);
@@ -86,9 +83,20 @@ int constant_time_memcmp(const void* a, const void *b, size_t n);
 /* Returns a time in seconds that doesn't go backwards - does not correspond to
 a real-world clock */
 time_t monotonic_now(void);
+/* Higher resolution clock_gettime(CLOCK_MONOTONIC) wrapper */
+void gettime_wrapper(struct timespec *now);
 
 char * expand_homedir_path(const char *inpath);
 
 void fsync_parent_dir(const char* fn);
 
+int fd_read_pending(int fd);
+
+#if DROPBEAR_MSAN
+/* FD_ZERO seems to leave some memory uninitialized. clear it to avoid false positives */
+#define DROPBEAR_FD_ZERO(fds) do { memset((fds), 0x0, sizeof(fd_set)); FD_ZERO(fds); } while(0)
+#else
+#define DROPBEAR_FD_ZERO(fds) FD_ZERO(fds)
+#endif
+
 #endif /* DROPBEAR_DBUTIL_H_ */

debian/changelog

@@ -1,3 +1,33 @@
+dropbear (2020.81-0.1) unstable; urgency=low
+
+  * New upstream release.
+
+ -- Matt Johnston <matt@ucc.asn.au>  Thu, 29 Oct 2020 22:51:57 +0800
+
+dropbear (2020.80-0.1) unstable; urgency=low
+
+  * New upstream release.
+
+ -- Matt Johnston <matt@ucc.asn.au>  Fri, 26 Jun 2020 22:51:57 +0800
+
+dropbear (2020.79-0.1) unstable; urgency=low
+
+  * New upstream release.
+
+ -- Matt Johnston <matt@ucc.asn.au>  Mon, 15 Jun 2020 22:51:57 +0800
+
+dropbear (2019.78-0.1) unstable; urgency=low
+
+  * New upstream release.
+
+ -- Matt Johnston <matt@ucc.asn.au>  Wed, 27 Mar 2019 22:51:57 +0800
+
+dropbear (2019.77-0.1) unstable; urgency=low
+
+  * New upstream release.
+
+ -- Matt Johnston <matt@ucc.asn.au>  Sat, 23 Mar 2019 22:51:57 +0800
+
 dropbear (2018.76-0.1) unstable; urgency=low
 
   * New upstream release.

debug.h

@@ -39,13 +39,9 @@
 /*#define CHECKCLEARTOWRITE() assert(ses.writepayload->len == 0 && \
 		ses.writepayload->pos == 0)*/
 
+#ifndef CHECKCLEARTOWRITE
 #define CHECKCLEARTOWRITE()
-
-/* Define this, compile with -pg and set GMON_OUT_PREFIX=gmon to get gmon
- * output when Dropbear forks. This will allow it gprof to be used.
- * It's useful to run dropbear -F, so you don't fork as much */
-/* (This is Linux specific) */
-/*#define DEBUG_FORKGPROF*/
+#endif
 
 /* A couple of flags, not usually useful, and mightn't do anything */
 
@@ -54,6 +50,7 @@
 
 /* you don't need to touch this block */
 #if DEBUG_TRACE
+extern int debug_trace;
 #define TRACE(X) dropbear_trace X;
 #define TRACE2(X) dropbear_trace2 X;
 #else /*DEBUG_TRACE*/
@@ -63,7 +60,9 @@
 
 /* To debug with GDB it is easier to run with no forking of child processes.
    You will need to pass "-F" as well. */
-/* #define DEBUG_NOFORK */
+#ifndef DEBUG_NOFORK
+#define DEBUG_NOFORK 0
+#endif
 
 
 /* For testing as non-root on shadowed systems, include the crypt of a password

default_options.h

@@ -6,8 +6,8 @@
 default_options.h  documents compile-time options, and provides default values.
 
 Local customisation should be added to localoptions.h which is
-used if it exists. Options defined there will override any options in this
-file.
+used if it exists in the build directory. Options defined there will override 
+any options in this file.
 
 Options can also be defined with -DDROPBEAR_XXX=[0,1] in Makefile CFLAGS
 
@@ -22,6 +22,7 @@ IMPORTANT: Some options will require "make clean" after changes */
 #define DSS_PRIV_FILENAME "/etc/dropbear/dropbear_dss_host_key"
 #define RSA_PRIV_FILENAME "/etc/dropbear/dropbear_rsa_host_key"
 #define ECDSA_PRIV_FILENAME "/etc/dropbear/dropbear_ecdsa_host_key"
+#define ED25519_PRIV_FILENAME "/etc/dropbear/dropbear_ed25519_host_key"
 
 /* Set NON_INETD_MODE if you require daemon functionality (ie Dropbear listens
  * on chosen ports and keeps accepting connections. This is the default.
@@ -47,7 +48,7 @@ IMPORTANT: Some options will require "make clean" after changes */
 #define DROPBEAR_SMALL_CODE 1
 
 /* Enable X11 Forwarding - server only */
-#define DROPBEAR_X11FWD 1
+#define DROPBEAR_X11FWD 0
 
 /* Enable TCP Fowarding */
 /* 'Local' is "-L" style (client listening port forwarded via server)
@@ -82,27 +83,36 @@ IMPORTANT: Some options will require "make clean" after changes */
  * Including both AES keysize variants (128 and 256) will result in 
  * a minimal size increase */
 #define DROPBEAR_AES128 1
-#define DROPBEAR_3DES 1
 #define DROPBEAR_AES256 1
+#define DROPBEAR_3DES 0
 #define DROPBEAR_TWOFISH256 0
 #define DROPBEAR_TWOFISH128 0
-/* Compiling in Blowfish will add ~6kB to runtime heap memory usage */
-#define DROPBEAR_BLOWFISH 0
+
+/* Enable Chacha20-Poly1305 authenticated encryption mode. This is
+ * generally faster than AES256 on CPU w/o dedicated AES instructions,
+ * having the same key size. Recommended.
+ * Compiling in will add ~5,5kB to binary size on x86-64 */
+#define DROPBEAR_CHACHA20POLY1305 1
+
+/* Enable "Counter Mode" for ciphers. Recommended. */
+#define DROPBEAR_ENABLE_CTR_MODE 1
 
 /* Enable CBC mode for ciphers. This has security issues though
- * is the most compatible with older SSH implementations */
-#define DROPBEAR_ENABLE_CBC_MODE 1
+   may be required for compatibility with old implementations */
+#define DROPBEAR_ENABLE_CBC_MODE 0
 
-/* Enable "Counter Mode" for ciphers. This is more secure than
- * CBC mode against certain attacks. It is recommended for security
- * and forwards compatibility */
-#define DROPBEAR_ENABLE_CTR_MODE 1
+/* Enable "Galois/Counter Mode" for ciphers. This authenticated
+ * encryption mode is combination of CTR mode and GHASH. Recommended
+ * for security and forwards compatibility, but slower than CTR on
+ * CPU w/o dedicated AES/GHASH instructions.
+ * Compiling in will add ~6kB to binary size on x86-64 */
+#define DROPBEAR_ENABLE_GCM_MODE 0
 
 /* Message integrity. sha2-256 is recommended as a default, 
    sha1 for compatibility */
 #define DROPBEAR_SHA1_HMAC 1
-#define DROPBEAR_SHA1_96_HMAC 1
 #define DROPBEAR_SHA2_256_HMAC 1
+#define DROPBEAR_SHA1_96_HMAC 0
 
 /* Hostkey/public key algorithms - at least one required, these are used
  * for hostkey as well as for verifying signatures with pubkey auth.
@@ -116,11 +126,17 @@ IMPORTANT: Some options will require "make clean" after changes */
  * code (either ECDSA or ECDH) increases binary size - around 30kB
  * on x86-64 */
 #define DROPBEAR_ECDSA 1
+#define DROPBEAR_SK_ECDSA 1
+/* Ed25519 is faster than ECDSA. Compiling in Ed25519 code increases
+   binary size - around 7,5kB on x86-64 */
+#define DROPBEAR_ED25519 1
+#define DROPBEAR_SK_ED25519 1
 
 /* RSA must be >=1024 */
 #define DROPBEAR_DEFAULT_RSA_SIZE 2048
 /* DSS is always 1024 */
 /* ECDSA defaults to largest size configured, usually 521 */
+/* Ed25519 is always 256 */
 
 /* Add runtime flag "-R" to generate hostkeys as-needed when the first 
    connection using that key type occurs.
@@ -143,7 +159,7 @@ IMPORTANT: Some options will require "make clean" after changes */
  * group14 is supported by most implementations.
  * group16 provides a greater strength level but is slower and increases binary size
  * curve25519 and ecdh algorithms are faster than non-elliptic curve methods
- * curve25519 increases binary size by ~8kB on x86-64
+ * curve25519 increases binary size by ~2,5kB on x86-64
  * including either ECDH or ECDSA increases binary size by ~30kB on x86-64
 
  * Small systems should generally include either curve25519 or ecdh for performance.
@@ -174,7 +190,7 @@ group1 in Dropbear server too */
 #define DO_HOST_LOOKUP 0
 
 /* Whether to print the message of the day (MOTD). */
-#define DO_MOTD 0
+#define DO_MOTD 1
 #define MOTD_FILENAME "/etc/motd"
 
 /* Authentication Types - at least one required.
@@ -196,6 +212,11 @@ group1 in Dropbear server too */
  * authorized_keys file into account */
 #define DROPBEAR_SVR_PUBKEY_OPTIONS 1
 
+/* Set this to 0 if your system does not have multiple user support.
+   (Linux kernel CONFIG_MULTIUSER option)
+   The resulting binary will not run on a normal system. */
+#define DROPBEAR_SVR_MULTIUSER 1
+
 /* Client authentication options */
 #define DROPBEAR_CLI_PASSWORD_AUTH 1
 #define DROPBEAR_CLI_PUBKEY_AUTH 1
@@ -237,6 +258,12 @@ Homedir is prepended unless path begins with / */
 /* -T server option overrides */
 #define MAX_AUTH_TRIES 10
 
+/* Delay introduced before closing an unauthenticated session (seconds).
+   Disabled by default, can be set to say 30 seconds to reduce the speed
+   of password brute forcing. Note that there is a risk of denial of 
+   service by setting this */
+#define UNAUTH_CLOSE_DELAY 0
+
 /* The default file to store the daemon's process ID, for shutdown
    scripts etc. This can be overridden with the -P flag */
 #define DROPBEAR_PIDFILE "/var/run/dropbear.pid"

dh_groups.c

@@ -1,6 +1,8 @@
 #include "options.h"
 #include "dh_groups.h"
 
+#if DROPBEAR_NORMAL_DH
+
 #if DROPBEAR_DH_GROUP1
 /* diffie-hellman-group1-sha1 value for p */
 const unsigned char dh_p_1[DH_P_1_LEN] = {
@@ -92,3 +94,4 @@ const unsigned char dh_p_16[DH_P_16_LEN] = {
 /* Same for all groups */
 const int DH_G_VAL = 2;
 
+#endif /* DROPBEAR_NORMAL_DH */

dh_groups.h

@@ -2,6 +2,8 @@
 #define DROPBEAR_DH_GROUPS_H
 #include "options.h"
 
+#if DROPBEAR_NORMAL_DH
+
 #if DROPBEAR_DH_GROUP1
 #define DH_P_1_LEN 128
 extern const unsigned char dh_p_1[DH_P_1_LEN];
@@ -17,8 +19,8 @@ extern const unsigned char dh_p_14[DH_P_14_LEN];
 extern const unsigned char dh_p_16[DH_P_16_LEN];
 #endif
 
-
 extern const int DH_G_VAL;
 
+#endif /* DROPBEAR_NORMAL_DH */
 
 #endif

dropbear.8

@@ -35,6 +35,12 @@ Don't fork into background.
 .B \-E
 Log to standard error rather than syslog.
 .TP
+.B \-e
+Pass on the server environment to all child processes. This is required, for example,
+if Dropbear is launched on the fly from a SLURM workload manager. The environment is not
+passed by default. Note that this could expose secrets in environment variables from 
+the calling process - use with caution.
+.TP
 .B \-m
 Don't display the message of the day on login.
 .TP
@@ -60,7 +66,7 @@ and TCP
 .I port.
 If just a port is given listen
 on all addresses.
-up to 10 can be specified (default 22 if none specified).
+Up to 10 can be specified (default 22 if none specified).
 .TP
 .B \-i
 Service program mode.
@@ -86,7 +92,7 @@ Ensure that traffic is transmitted at a certain interval in seconds. This is
 useful for working around firewalls or routers that drop connections after
 a certain period of inactivity. The trade-off is that a session may be
 closed if there is a temporary lapse of network connectivity. A setting
-if 0 disables keepalives. If no response is received for 3 consecutive keepalives the connection will be closed.
+of 0 disables keepalives. If no response is received for 3 consecutive keepalives the connection will be closed.
 .TP
 .B \-I \fIidle_timeout
 Disconnect the session if no traffic is transmitted or received for \fIidle_timeout\fR seconds.
@@ -96,7 +102,8 @@ Set the number of authentication attempts allowed per connection. If unspecified
 .TP
 .B \-c \fIforced_command
 Disregard the command provided by the user and always run \fIforced_command\fR. This also
-overrides any authorized_keys command= option.
+overrides any authorized_keys command= option. The original command is saved in the 
+SSH_ORIGINAL_COMMAND environment variable (see below).
 .TP
 .B \-V
 Print the version
@@ -107,7 +114,7 @@ Print the version
 Authorized Keys
 
 ~/.ssh/authorized_keys can be set up to allow remote login with a RSA,
-ECDSA, or DSS
+ECDSA, Ed25519 or DSS
 key. Each line is of the form
 .TP
 [restrictions] ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIgAsp... [comment]
@@ -133,6 +140,10 @@ Don't allow X11 forwarding for this connection
 Disable PTY allocation. Note that a user can still obtain most of the
 same functionality with other means even if no-pty is set.
 
+.TP
+.B restrict
+Applies all the no- restrictions listed above.
+
 .TP
 .B command=\fR"\fIforced_command\fR"
 Disregard the command provided by the user and always run \fIforced_command\fR.
@@ -146,8 +157,8 @@ key authentication.
 Host Key Files
 
 Host key files are read at startup from a standard location, by default
-/etc/dropbear/dropbear_dss_host_key, /etc/dropbear/dropbear_rsa_host_key, and 
-/etc/dropbear/dropbear_ecdsa_host_key
+/etc/dropbear/dropbear_dss_host_key, /etc/dropbear/dropbear_rsa_host_key,
+/etc/dropbear/dropbear_ecdsa_host_key and /etc/dropbear/dropbear_ed25519_host_key
 
 If the -r command line option is specified the default files are not loaded.
 Host key files are of the form generated by dropbearkey. 

dropbear_lint.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+EXITCODE=0
+
+# #ifdef instead of #if
+grep '#ifdef DROPBEAR' -I *.c *.h && EXITCODE=1
+
+exit $EXITCODE

dropbearkey.1

@@ -13,7 +13,7 @@ dropbearkey \- create private keys for the use with dropbear(8) or dbclient(1)
 .SH DESCRIPTION
 .B dropbearkey
 generates a
-\fIRSA\fR, \fIDSS\fR, or \fIECDSA\fR
+\fIRSA\fR, \fIDSS\fR, \fIECDSA\fR, or \fIEd25519\fR
 format SSH private key, and saves it to a file for the use with the
 Dropbear client or server.
 Note that 
@@ -26,6 +26,7 @@ Type of key to generate.
 Must be one of
 .I rsa
 .I ecdsa
+.I ed25519
 or
 .IR dss .
 .TP

dropbearkey.c

@@ -43,6 +43,10 @@
  * mp_int	y
  * mp_int	x
  *
+ * Ed25519:
+ * string	"ssh-ed25519"
+ * string	k (32 bytes) + A (32 bytes)
+ *
  */
 #include "includes.h"
 #include "signkey.h"
@@ -51,6 +55,7 @@
 
 #include "genrsa.h"
 #include "gendss.h"
+#include "gened25519.h"
 #include "ecdsa.h"
 #include "crypto_desc.h"
 #include "dbrandom.h"
@@ -75,6 +80,9 @@ static void printhelp(char * progname) {
 #endif
 #if DROPBEAR_ECDSA
 					"		ecdsa\n"
+#endif
+#if DROPBEAR_ED25519
+					"		ed25519\n"
 #endif
 					"-f filename    Use filename for the secret key.\n"
 					"               ~/.ssh/id_dropbear is recommended for client keys.\n"
@@ -94,6 +102,9 @@ static void printhelp(char * progname) {
 					"521 "
 #endif
 					"\n"
+#endif
+#if DROPBEAR_ED25519
+					"           Ed25519 has a fixed size of 256 bits\n"
 #endif
 					"-y		Just print the publickey and fingerprint for the\n		private key in <filename>.\n"
 #if DEBUG_TRACE
@@ -106,6 +117,14 @@ static void printhelp(char * progname) {
 static void check_signkey_bits(enum signkey_type type, int bits)
 {
 	switch (type) {
+#if DROPBEAR_ED25519
+		case DROPBEAR_SIGNKEY_ED25519:
+			if (bits != 256) {
+				dropbear_exit("Ed25519 keys have a fixed size of 256 bits\n");
+				exit(EXIT_FAILURE);
+			}
+			break;
+#endif
 #if DROPBEAR_RSA
 		case DROPBEAR_SIGNKEY_RSA:
 			if (bits < 512 || bits > 4096 || (bits % 8 != 0)) {
@@ -114,7 +133,7 @@ static void check_signkey_bits(enum signkey_type type, int bits)
 			}
 			break;
 #endif
-#ifdef DROPEAR_DSS
+#if DROPEAR_DSS
 		case DROPBEAR_SIGNKEY_DSS:
 			if (bits != 1024) {
 				dropbear_exit("DSS keys have a fixed size of 1024 bits\n");
@@ -224,6 +243,12 @@ int main(int argc, char ** argv) {
 		keytype = DROPBEAR_SIGNKEY_ECDSA_KEYGEN;
 	}
 #endif
+#if DROPBEAR_ED25519
+	if (strcmp(typetext, "ed25519") == 0)
+	{
+		keytype = DROPBEAR_SIGNKEY_ED25519;
+	}
+#endif
 
 	if (keytype == DROPBEAR_SIGNKEY_NONE) {
 		fprintf(stderr, "Unknown key type '%s'\n", typetext);

dss.c

@@ -73,6 +73,18 @@ int buf_get_dss_pub_key(buffer* buf, dropbear_dss_key *key) {
 		goto out;
 	}
 
+	/* test 1 < g < p */
+	if (mp_cmp_d(key->g, 1) != MP_GT) {
+		dropbear_log(LOG_WARNING, "Bad DSS g");
+		ret = DROPBEAR_FAILURE;
+		goto out;
+	}
+	if (mp_cmp(key->g, key->p) != MP_LT) {
+		dropbear_log(LOG_WARNING, "Bad DSS g");
+		ret = DROPBEAR_FAILURE;
+		goto out;
+	}
+
 	ret = DROPBEAR_SUCCESS;
 	TRACE(("leave buf_get_dss_pub_key: success"))
 out:
@@ -172,6 +184,13 @@ int buf_dss_verify(buffer* buf, const dropbear_dss_key *key, const buffer *data_
 		goto out;
 	}
 
+#if DEBUG_DSS_VERIFY
+	printmpint("dss verify p", key->p);
+	printmpint("dss verify q", key->q);
+	printmpint("dss verify g", key->g);
+	printmpint("dss verify y", key->y);
+#endif
+
 	/* hash the data */
 	sha1_init(&hs);
 	sha1_process(&hs, data_buf->data, data_buf->len);
@@ -181,6 +200,9 @@ int buf_dss_verify(buffer* buf, const dropbear_dss_key *key, const buffer *data_
 	/* w = (s')-1 mod q */
 	/* let val1 = s' */
 	bytes_to_mp(&val1, (const unsigned char*) &string[SHA1_HASH_SIZE], SHA1_HASH_SIZE);
+#if DEBUG_DSS_VERIFY
+	printmpint("dss verify s'", &val1);
+#endif
 
 	if (mp_cmp(&val1, key->q) != MP_LT) {
 		TRACE(("verify failed, s' >= q"))
@@ -198,6 +220,9 @@ int buf_dss_verify(buffer* buf, const dropbear_dss_key *key, const buffer *data_
 	/* u1 = ((SHA(M')w) mod q */
 	/* let val1 = SHA(M') = msghash */
 	bytes_to_mp(&val1, msghash, SHA1_HASH_SIZE);
+#if DEBUG_DSS_VERIFY
+	printmpint("dss verify r'", &val1);
+#endif
 
 	/* let val3 = u1 = ((SHA(M')w) mod q */
 	if (mp_mulmod(&val1, &val2, key->q, &val3) != MP_OKAY) {
@@ -259,6 +284,7 @@ void buf_put_dss_sign(buffer* buf, const dropbear_dss_key *key, const buffer *da
 	unsigned char msghash[SHA1_HASH_SIZE];
 	unsigned int writelen;
 	unsigned int i;
+	size_t written;
 	DEF_MP_INT(dss_k);
 	DEF_MP_INT(dss_m);
 	DEF_MP_INT(dss_temp1);
@@ -315,31 +341,31 @@ void buf_put_dss_sign(buffer* buf, const dropbear_dss_key *key, const buffer *da
 	buf_putstring(buf, SSH_SIGNKEY_DSS, SSH_SIGNKEY_DSS_LEN);
 	buf_putint(buf, 2*SHA1_HASH_SIZE);
 
-	writelen = mp_unsigned_bin_size(&dss_r);
+	writelen = mp_ubin_size(&dss_r);
 	dropbear_assert(writelen <= SHA1_HASH_SIZE);
 	/* need to pad to 160 bits with leading zeros */
 	for (i = 0; i < SHA1_HASH_SIZE - writelen; i++) {
 		buf_putbyte(buf, 0);
 	}
-	if (mp_to_unsigned_bin(&dss_r, buf_getwriteptr(buf, writelen)) 
+	if (mp_to_ubin(&dss_r, buf_getwriteptr(buf, writelen), writelen, &written)
 			!= MP_OKAY) {
 		dropbear_exit("DSS error");
 	}
 	mp_clear(&dss_r);
-	buf_incrwritepos(buf, writelen);
+	buf_incrwritepos(buf, written);
 
-	writelen = mp_unsigned_bin_size(&dss_s);
+	writelen = mp_ubin_size(&dss_s);
 	dropbear_assert(writelen <= SHA1_HASH_SIZE);
 	/* need to pad to 160 bits with leading zeros */
 	for (i = 0; i < SHA1_HASH_SIZE - writelen; i++) {
 		buf_putbyte(buf, 0);
 	}
-	if (mp_to_unsigned_bin(&dss_s, buf_getwriteptr(buf, writelen)) 
+	if (mp_to_ubin(&dss_s, buf_getwriteptr(buf, writelen), writelen, &written)
 			!= MP_OKAY) {
 		dropbear_exit("DSS error");
 	}
 	mp_clear(&dss_s);
-	buf_incrwritepos(buf, writelen);
+	buf_incrwritepos(buf, written);
 
 	mp_clear_multi(&dss_k, &dss_temp1, &dss_temp2, &dss_r, &dss_s,
 			&dss_m, NULL);

dss.h

@@ -30,7 +30,7 @@
 
 #if DROPBEAR_DSS 
 
-typedef struct {
+typedef struct dropbear_DSS_Key {
 
 	mp_int* p;
 	mp_int* q;

ecc.c

@@ -166,13 +166,13 @@ ecc_key * buf_get_ecc_raw_pubkey(buffer *buf, const struct dropbear_ecc_curve *c
 	key = new_ecc_key();
 	key->dp = curve->dp;
 
-	if (mp_read_unsigned_bin(key->pubkey.x, buf_getptr(buf, size), size) != MP_OKAY) {
+	if (mp_from_ubin(key->pubkey.x, buf_getptr(buf, size), size) != MP_OKAY) {
 		TRACE(("failed to read x"))
 		goto out;
 	}
 	buf_incrpos(buf, size);
 
-	if (mp_read_unsigned_bin(key->pubkey.y, buf_getptr(buf, size), size) != MP_OKAY) {
+	if (mp_from_ubin(key->pubkey.y, buf_getptr(buf, size), size) != MP_OKAY) {
 		TRACE(("failed to read y"))
 		goto out;
 	}

ecdsa.c

@@ -81,18 +81,25 @@ ecc_key *buf_get_ecdsa_pub_key(buffer* buf) {
 	struct dropbear_ecc_curve **curve;
 	ecc_key *new_key = NULL;
 
-	/* string   "ecdsa-sha2-[identifier]" */
+	/* string   "ecdsa-sha2-[identifier]" or "sk-ecdsa-sha2-nistp256@openssh.com" */
 	key_ident = (unsigned char*)buf_getstring(buf, &key_ident_len);
 	/* string   "[identifier]" */
 	identifier = (unsigned char*)buf_getstring(buf, &identifier_len);
 
-	if (key_ident_len != identifier_len + strlen("ecdsa-sha2-")) {
-		TRACE(("Bad identifier lengths"))
-		goto out;
-	}
-	if (memcmp(&key_ident[strlen("ecdsa-sha2-")], identifier, identifier_len) != 0) {
-		TRACE(("mismatching identifiers"))
-		goto out;
+	if (strcmp (key_ident, "sk-ecdsa-sha2-nistp256@openssh.com") == 0) {
+		if (strcmp (identifier, "nistp256") != 0) {
+			TRACE(("mismatching identifiers"))
+			goto out;
+		}
+	} else {
+		if (key_ident_len != identifier_len + strlen ("ecdsa-sha2-")) {
+			TRACE(("Bad identifier lengths"))
+			goto out;
+		}
+		if (memcmp(&key_ident[strlen ("ecdsa-sha2-")], identifier, identifier_len) != 0) {
+			TRACE(("mismatching identifiers"))
+			goto out;
+		}
 	}
 
 	for (curve = dropbear_ecc_curves; *curve; curve++) {

ecdsa.h

@@ -16,7 +16,7 @@
 #elif DROPBEAR_ECC_521
 #define ECDSA_DEFAULT_SIZE 521
 #else
-#define ECDSA_DEFAULT_SIZE 0
+#error ECDSA cannot be enabled without enabling at least one size (256, 384, 521)
 #endif
 
 ecc_key *gen_ecdsa_priv_key(unsigned int bit_size);

ed25519.c

@@ -0,0 +1,193 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+/* Perform Ed25519 operations on data, including reading keys, signing and
+ * verification. */
+
+#include "includes.h"
+#include "dbutil.h"
+#include "buffer.h"
+#include "ssh.h"
+#include "curve25519.h"
+#include "ed25519.h"
+
+#if DROPBEAR_ED25519
+
+/* Load a public ed25519 key from a buffer, initialising the values.
+ * The key will have the same format as buf_put_ed25519_key.
+ * These should be freed with ed25519_key_free.
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key,
+	enum signkey_type expect_keytype) {
+
+
+	unsigned int len, typelen;
+	char *keytype = NULL;
+	enum signkey_type buf_keytype;
+
+	TRACE(("enter buf_get_ed25519_pub_key"))
+	dropbear_assert(key != NULL);
+
+	/* consume and check the key string */
+	keytype = buf_getstring(buf, &typelen);
+	buf_keytype = signkey_type_from_name(keytype, typelen);
+	m_free(keytype);
+	if (buf_keytype != expect_keytype) {
+		TRACE(("leave buf_get_ed25519_pub_key: mismatch key type"))
+		return DROPBEAR_FAILURE;
+	}
+
+	len = buf_getint(buf);
+	if (len != CURVE25519_LEN || buf->len - buf->pos < len) {
+		TRACE(("leave buf_get_ed25519_pub_key: failure"))
+		return DROPBEAR_FAILURE;
+	}
+
+	m_burn(key->priv, CURVE25519_LEN);
+	memcpy(key->pub, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+
+	TRACE(("leave buf_get_ed25519_pub_key: success"))
+	return DROPBEAR_SUCCESS;
+}
+
+/* Same as buf_get_ed25519_pub_key, but reads private key at the end.
+ * Loads a public and private ed25519 key from a buffer
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_get_ed25519_priv_key(buffer *buf, dropbear_ed25519_key *key) {
+
+	unsigned int len;
+
+	TRACE(("enter buf_get_ed25519_priv_key"))
+	dropbear_assert(key != NULL);
+
+	buf_incrpos(buf, 4+SSH_SIGNKEY_ED25519_LEN); /* int + "ssh-ed25519" */
+
+	len = buf_getint(buf);
+	if (len != CURVE25519_LEN*2 || buf->len - buf->pos < len) {
+		TRACE(("leave buf_get_ed25519_priv_key: failure"))
+		return DROPBEAR_FAILURE;
+	}
+
+	memcpy(key->priv, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+	memcpy(key->pub, buf_getptr(buf, CURVE25519_LEN), CURVE25519_LEN);
+	buf_incrpos(buf, CURVE25519_LEN);
+
+	TRACE(("leave buf_get_ed25519_priv_key: success"))
+	return DROPBEAR_SUCCESS;
+}
+
+/* Clear and free the memory used by a public or private key */
+void ed25519_key_free(dropbear_ed25519_key *key) {
+
+	TRACE2(("enter ed25519_key_free"))
+
+	if (key == NULL) {
+		TRACE2(("leave ed25519_key_free: key == NULL"))
+		return;
+	}
+	m_burn(key->priv, CURVE25519_LEN);
+	m_free(key);
+
+	TRACE2(("leave ed25519_key_free"))
+}
+
+/* Put the public ed25519 key into the buffer in the required format */
+void buf_put_ed25519_pub_key(buffer *buf, const dropbear_ed25519_key *key) {
+
+	TRACE(("enter buf_put_ed25519_pub_key"))
+	dropbear_assert(key != NULL);
+
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putstring(buf, key->pub, CURVE25519_LEN);
+
+	TRACE(("leave buf_put_ed25519_pub_key"))
+}
+
+/* Put the public and private ed25519 key into the buffer in the required format */
+void buf_put_ed25519_priv_key(buffer *buf, const dropbear_ed25519_key *key) {
+
+	TRACE(("enter buf_put_ed25519_priv_key"))
+	dropbear_assert(key != NULL);
+
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putint(buf, CURVE25519_LEN*2);
+	buf_putbytes(buf, key->priv, CURVE25519_LEN);
+	buf_putbytes(buf, key->pub, CURVE25519_LEN);
+
+	TRACE(("leave buf_put_ed25519_priv_key"))
+}
+
+/* Sign the data presented with key, writing the signature contents
+ * to the buffer */
+void buf_put_ed25519_sign(buffer* buf, const dropbear_ed25519_key *key, const buffer *data_buf) {
+
+	unsigned char s[64];
+	unsigned long slen = sizeof(s);
+
+	TRACE(("enter buf_put_ed25519_sign"))
+	dropbear_assert(key != NULL);
+
+	dropbear_ed25519_sign(data_buf->data, data_buf->len, s, &slen, key->priv, key->pub);
+	buf_putstring(buf, SSH_SIGNKEY_ED25519, SSH_SIGNKEY_ED25519_LEN);
+	buf_putstring(buf, s, slen);
+
+	TRACE(("leave buf_put_ed25519_sign"))
+}
+
+#if DROPBEAR_SIGNKEY_VERIFY
+/* Verify a signature in buf, made on data by the key given.
+ * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
+int buf_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf) {
+
+	int ret = DROPBEAR_FAILURE;
+	unsigned char *s;
+	unsigned long slen;
+
+	TRACE(("enter buf_ed25519_verify"))
+	dropbear_assert(key != NULL);
+
+	slen = buf_getint(buf);
+	if (slen != 64 || buf->len - buf->pos < slen) {
+		TRACE(("leave buf_ed25519_verify: bad size"))
+		goto out;
+	}
+	s = buf_getptr(buf, slen);
+
+	if (dropbear_ed25519_verify(data_buf->data, data_buf->len,
+				    s, slen, key->pub) == 0) {
+		/* signature is valid */
+		TRACE(("leave buf_ed25519_verify: success!"))
+		ret = DROPBEAR_SUCCESS;
+	}
+
+out:
+	TRACE(("leave buf_ed25519_verify: ret %d", ret))
+	return ret;
+}
+
+#endif /* DROPBEAR_SIGNKEY_VERIFY */
+
+#endif /* DROPBEAR_ED25519 */

ed25519.h

@@ -0,0 +1,56 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#ifndef DROPBEAR_ED25519_H_
+#define DROPBEAR_ED25519_H_
+
+#include "includes.h"
+#include "buffer.h"
+#include "signkey.h"
+
+#if DROPBEAR_ED25519 
+
+#define CURVE25519_LEN 32
+
+typedef struct dropbear_ED25519_Key {
+
+	unsigned char priv[CURVE25519_LEN];
+	unsigned char pub[CURVE25519_LEN];
+
+} dropbear_ed25519_key;
+
+void buf_put_ed25519_sign(buffer* buf, const dropbear_ed25519_key *key, const buffer *data_buf);
+#if DROPBEAR_SIGNKEY_VERIFY
+int buf_ed25519_verify(buffer * buf, const dropbear_ed25519_key *key, const buffer *data_buf);
+#endif
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key,
+        enum signkey_type expect_keytype);
+int buf_get_ed25519_priv_key(buffer* buf, dropbear_ed25519_key *key);
+void buf_put_ed25519_pub_key(buffer* buf, const dropbear_ed25519_key *key);
+void buf_put_ed25519_priv_key(buffer* buf, const dropbear_ed25519_key *key);
+void ed25519_key_free(dropbear_ed25519_key *key);
+
+#endif /* DROPBEAR_ED25519 */
+
+#endif /* DROPBEAR_ED25519_H_ */

filelist.txt

@@ -99,6 +99,10 @@ rsa.c			RSA asymmetric crypto routines
 
 dss.c			DSS asymmetric crypto routines
 
+ed25519.c		Ed25519 asymmetric crypto routines
+
+gened25519.c		Ed25519 key generation
+
 gendss.c		DSS key generation
 
 genrsa.c		RSA key generation

fuzz-wrapfd.h

@@ -0,0 +1,27 @@
+#ifndef FUZZ_WRAPFD_H
+#define FUZZ_WRAPFD_H
+
+#include "includes.h"
+#include "buffer.h"
+
+enum wrapfd_mode {
+    UNUSED = 0,
+    COMMONBUF, // using the common buffer
+    DUMMY, // reads return fixed output, of random length
+};
+
+// buf is a common buffer read by all wrapped FDs. doesn't take ownership of buf
+void wrapfd_setup(buffer *buf);
+void wrapfd_setseed(uint32_t seed);
+int wrapfd_new_fuzzinput(void);
+int wrapfd_new_dummy(void);
+
+// called via #defines for read/write/select
+int wrapfd_read(int fd, void *out, size_t count);
+int wrapfd_write(int fd, const void* in, size_t count);
+int wrapfd_select(int nfds, fd_set *readfds, fd_set *writefds, 
+    fd_set *exceptfds, struct timeval *timeout);
+int wrapfd_close(int fd);
+int fuzz_kill(pid_t pid, int sig);
+
+#endif // FUZZ_WRAPFD_H

fuzz.h

@@ -0,0 +1,114 @@
+#ifndef DROPBEAR_FUZZ_H
+#define DROPBEAR_FUZZ_H
+
+#include "config.h"
+
+#if DROPBEAR_FUZZ
+
+#include "includes.h"
+#include "buffer.h"
+#include "algo.h"
+#include "netio.h"
+#include "fuzz-wrapfd.h"
+
+// once per process
+void fuzz_common_setup(void);
+void fuzz_svr_setup(void);
+void fuzz_cli_setup(void);
+
+// constructor attribute so it runs before main(), including
+// in non-fuzzing mode.
+void fuzz_early_setup(void) __attribute__((constructor));
+
+// must be called once per fuzz iteration. 
+// returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE
+int fuzz_set_input(const uint8_t *Data, size_t Size);
+
+int fuzz_run_server(const uint8_t *Data, size_t Size, int skip_kexmaths, int postauth);
+int fuzz_run_client(const uint8_t *Data, size_t Size, int skip_kexmaths);
+const void* fuzz_get_algo(const algo_type *algos, const char* name);
+
+// fuzzer functions that intrude into general code
+void fuzz_kex_fakealgos(void);
+int fuzz_checkpubkey_line(buffer* line, int line_num, char* filename,
+        const char* algo, unsigned int algolen,
+        const unsigned char* keyblob, unsigned int keybloblen);
+extern const char * const * fuzz_signkey_names;
+void fuzz_seed(const unsigned char* dat, unsigned int len);
+void fuzz_svr_hook_preloop(void);
+
+int fuzz_dropbear_listen(const char* address, const char* port,
+        int *socks, unsigned int sockcount, char **errstring, int *maxfd);
+
+// helpers
+void fuzz_get_socket_address(int fd, char **local_host, char **local_port,
+                        char **remote_host, char **remote_port, int host_lookup);
+void fuzz_fake_send_kexdh_reply(void);
+int fuzz_spawn_command(int *ret_writefd, int *ret_readfd, int *ret_errfd, pid_t *ret_pid);
+void fuzz_dump(const unsigned char* data, size_t len);
+
+// fake IO wrappers
+#ifndef FUZZ_SKIP_WRAP
+#define select(nfds, readfds, writefds, exceptfds, timeout) \
+        wrapfd_select(nfds, readfds, writefds, exceptfds, timeout)
+#define write(fd, buf, count) wrapfd_write(fd, buf, count)
+#define read(fd, buf, count) wrapfd_read(fd, buf, count)
+#define close(fd) wrapfd_close(fd)
+#define kill(pid, sig) fuzz_kill(pid, sig)
+#endif // FUZZ_SKIP_WRAP
+
+struct dropbear_fuzz_options {
+    int fuzzing;
+
+    // fuzzing input
+    buffer *input;
+    struct dropbear_cipher recv_cipher;
+    struct dropbear_hash recv_mac;
+    int wrapfds;
+
+    // whether to skip slow bignum maths
+    int skip_kexmaths;
+    // whether is svr_postauth mode
+    int svr_postauth;
+
+    // dropbear_exit() jumps back
+    int do_jmp;
+    sigjmp_buf jmp;
+
+    // write out decrypted session data to this FD if it is set
+    // flag - this needs to be set manually in cli-main.c etc
+    int dumping;
+    // the file descriptor
+    int recv_dumpfd;
+
+    // avoid filling fuzzing logs, this points to /dev/null
+    FILE *fake_stderr;
+};
+
+extern struct dropbear_fuzz_options fuzz;
+
+/* guard for when fuzz.h is included by fuzz-common.c */
+#ifndef FUZZ_NO_REPLACE_STDERR
+
+/* This is a bodge but seems to work.
+ glibc stdio.h has the comment 
+ "C89/C99 say they're macros.  Make them happy." */
+/* OS X has it as a macro */
+#ifdef stderr
+#undef stderr
+#endif
+#define stderr (fuzz.fake_stderr)
+
+#endif /* FUZZ_NO_REPLACE_STDERR */
+
+struct passwd* fuzz_getpwuid(uid_t uid);
+struct passwd* fuzz_getpwnam(const char *login);
+/* guard for when fuzz.h is included by fuzz-common.c */
+#ifndef FUZZ_NO_REPLACE_GETPW
+#define getpwnam(x) fuzz_getpwnam(x)
+#define getpwuid(x) fuzz_getpwuid(x)
+#endif // FUZZ_NO_REPLACE_GETPW
+
+#endif /* DROPBEAR_FUZZ */
+
+#endif /* DROPBEAR_FUZZ_H */

fuzz/fuzz-common.c

@@ -0,0 +1,398 @@
+#define FUZZ_NO_REPLACE_STDERR
+#define FUZZ_NO_REPLACE_GETPW
+#include "includes.h"
+
+#include "includes.h"
+#include "dbutil.h"
+#include "runopts.h"
+#include "crypto_desc.h"
+#include "session.h"
+#include "dbrandom.h"
+#include "bignum.h"
+#include "atomicio.h"
+#include "fuzz-wrapfd.h"
+#include "fuzz.h"
+
+struct dropbear_fuzz_options fuzz;
+
+static void fuzz_dropbear_log(int UNUSED(priority), const char* format, va_list param);
+static void load_fixed_hostkeys(void);
+static void load_fixed_client_key(void);
+
+// This runs automatically before main, due to contructor attribute in fuzz.h
+void fuzz_early_setup(void) {
+    /* Set stderr to point to normal stderr by default */
+    fuzz.fake_stderr = stderr;
+}
+
+void fuzz_common_setup(void) {
+	disallow_core();
+    fuzz.fuzzing = 1;
+    fuzz.wrapfds = 1;
+    fuzz.do_jmp = 1;
+    fuzz.input = m_malloc(sizeof(buffer));
+    _dropbear_log = fuzz_dropbear_log;
+    crypto_init();
+    fuzz_seed("start", 5);
+    /* let any messages get flushed */
+    setlinebuf(stdout);
+#if DEBUG_TRACE
+    if (debug_trace)
+    {
+        fprintf(stderr, "Dropbear fuzzer: -v specified, not disabling stderr output\n");
+    }
+    else
+#endif
+    if (getenv("DROPBEAR_KEEP_STDERR")) {
+        fprintf(stderr, "Dropbear fuzzer: DROPBEAR_KEEP_STDERR, not disabling stderr output\n");
+    } 
+    else 
+    {
+        fprintf(stderr, "Dropbear fuzzer: Disabling stderr output\n");
+        fuzz.fake_stderr = fopen("/dev/null", "w");
+        assert(fuzz.fake_stderr);
+    }
+}
+
+int fuzz_set_input(const uint8_t *Data, size_t Size) {
+
+    fuzz.input->data = (unsigned char*)Data;
+    fuzz.input->size = Size;
+    fuzz.input->len = Size;
+    fuzz.input->pos = 0;
+
+    memset(&ses, 0x0, sizeof(ses));
+    memset(&svr_ses, 0x0, sizeof(svr_ses));
+    memset(&cli_ses, 0x0, sizeof(cli_ses));
+    wrapfd_setup(fuzz.input);
+    // printhex("input", fuzz.input->data, fuzz.input->len);
+
+    fuzz_seed(fuzz.input->data, MIN(fuzz.input->len, 16));
+
+    return DROPBEAR_SUCCESS;
+}
+
+#if DEBUG_TRACE
+static void fuzz_dropbear_log(int UNUSED(priority), const char* format, va_list param) {
+    if (debug_trace) {
+        char printbuf[1024];
+        vsnprintf(printbuf, sizeof(printbuf), format, param);
+        fprintf(stderr, "%s\n", printbuf);
+    }
+}
+#else
+static void fuzz_dropbear_log(int UNUSED(priority), const char* UNUSED(format), va_list UNUSED(param)) {
+    /* No print */
+}
+#endif /* DEBUG_TRACE */
+
+void fuzz_svr_setup(void) {
+    fuzz_common_setup();
+    
+    _dropbear_exit = svr_dropbear_exit;
+
+    char *argv[] = { 
+		"dropbear",
+        "-E", 
+    };
+
+    int argc = sizeof(argv) / sizeof(*argv);
+    svr_getopts(argc, argv);
+
+    load_fixed_hostkeys();
+}
+
+void fuzz_svr_hook_preloop() {
+    if (fuzz.svr_postauth) {
+        ses.authstate.authdone = 1;
+        fill_passwd("root");
+    }
+}
+
+void fuzz_cli_setup(void) {
+    fuzz_common_setup();
+    
+	_dropbear_exit = cli_dropbear_exit;
+	_dropbear_log = cli_dropbear_log;
+
+    char *argv[] = { 
+		"dbclient",
+		"-y",
+        "localhost",
+        "uptime"
+    };
+
+    int argc = sizeof(argv) / sizeof(*argv);
+    cli_getopts(argc, argv);
+
+    load_fixed_client_key();
+    /* Avoid password prompt */
+    setenv(DROPBEAR_PASSWORD_ENV, "password", 1);
+}
+
+#include "fuzz-hostkeys.c"   
+
+static void load_fixed_client_key(void) {
+
+    buffer *b = buf_new(3000);
+    sign_key *key;
+    enum signkey_type keytype;
+
+    key = new_sign_key();
+    keytype = DROPBEAR_SIGNKEY_ANY;
+    buf_putbytes(b, keyed25519, keyed25519_len);
+    buf_setpos(b, 0);
+    if (buf_get_priv_key(b, key, &keytype) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ed25519 hostkey");
+    }
+    list_append(cli_opts.privkeys, key);
+
+    buf_free(b);
+}
+
+static void load_fixed_hostkeys(void) {
+
+    buffer *b = buf_new(3000);
+    enum signkey_type type;
+
+    TRACE(("load fixed hostkeys"))
+
+    svr_opts.hostkey = new_sign_key();
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyr, keyr_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_RSA;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed rsa hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyd, keyd_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_DSS;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed dss hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keye, keye_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ecdsa hostkey");
+    }
+
+    buf_setlen(b, 0);
+    buf_putbytes(b, keyed25519, keyed25519_len);
+    buf_setpos(b, 0);
+    type = DROPBEAR_SIGNKEY_ED25519;
+    if (buf_get_priv_key(b, svr_opts.hostkey, &type) == DROPBEAR_FAILURE) {
+        dropbear_exit("failed fixed ed25519 hostkey");
+    }
+
+    buf_free(b);
+}
+
+void fuzz_kex_fakealgos(void) {
+    ses.newkeys->recv.crypt_mode = &dropbear_mode_none;
+    ses.newkeys->recv.algo_mac = &dropbear_nohash;
+}
+
+void fuzz_get_socket_address(int UNUSED(fd), char **local_host, char **local_port,
+                        char **remote_host, char **remote_port, int UNUSED(host_lookup)) {
+    if (local_host) {
+        *local_host = m_strdup("fuzzlocalhost");
+    }
+    if (local_port) {
+        *local_port = m_strdup("1234");
+    }
+    if (remote_host) {
+        *remote_host = m_strdup("fuzzremotehost");
+    }
+    if (remote_port) {
+        *remote_port = m_strdup("9876");
+    }
+}
+
+/* cut down version of svr_send_msg_kexdh_reply() that skips slow maths. Still populates structures */
+void fuzz_fake_send_kexdh_reply(void) {
+    assert(!ses.dh_K);
+    m_mp_alloc_init_multi(&ses.dh_K, NULL);
+    mp_set_ul(ses.dh_K, 12345678uL);
+    finish_kexhashbuf();
+}
+
+/* fake version of spawn_command() */
+int fuzz_spawn_command(int *ret_writefd, int *ret_readfd, int *ret_errfd, pid_t *ret_pid) {
+    *ret_writefd = wrapfd_new_dummy();
+    *ret_readfd = wrapfd_new_dummy();
+    if (ret_errfd) {
+        *ret_errfd = wrapfd_new_dummy();
+    }
+    if (*ret_writefd == -1 || *ret_readfd == -1 || (ret_errfd && *ret_errfd == -1)) {
+        m_close(*ret_writefd);
+        m_close(*ret_readfd);
+        if (ret_errfd) {
+            m_close(*ret_errfd);
+        }
+        return DROPBEAR_FAILURE;
+    } else {
+        *ret_pid = 999;
+        return DROPBEAR_SUCCESS;
+
+    }
+}
+
+/* Fake dropbear_listen, always returns failure for now.
+TODO make it sometimes return success with wrapfd_new_dummy() sockets.
+Making the listeners fake a new incoming connection will be harder. */
+/* Listen on address:port. 
+ * Special cases are address of "" listening on everything,
+ * and address of NULL listening on localhost only.
+ * Returns the number of sockets bound on success, or -1 on failure. On
+ * failure, if errstring wasn't NULL, it'll be a newly malloced error
+ * string.*/
+int fuzz_dropbear_listen(const char* UNUSED(address), const char* UNUSED(port),
+        int *UNUSED(socks), unsigned int UNUSED(sockcount), char **errstring, int *UNUSED(maxfd)) {
+    if (errstring) {
+        *errstring = m_strdup("fuzzing can't listen (yet)");
+    }
+    return -1;
+}
+
+int fuzz_run_server(const uint8_t *Data, size_t Size, int skip_kexmaths, int postauth) {
+    static int once = 0;
+    if (!once) {
+        fuzz_svr_setup();
+        fuzz.skip_kexmaths = skip_kexmaths;
+        once = 1;
+    }
+
+    fuzz.svr_postauth = postauth;
+
+    if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+        return 0;
+    }
+
+    uint32_t wrapseed;
+    genrandom((void*)&wrapseed, sizeof(wrapseed));
+    wrapfd_setseed(wrapseed);
+
+    int fakesock = wrapfd_new_fuzzinput();
+
+    m_malloc_set_epoch(1);
+    fuzz.do_jmp = 1;
+    if (setjmp(fuzz.jmp) == 0) {
+        svr_session(fakesock, fakesock);
+        m_malloc_free_epoch(1, 0);
+    } else {
+        fuzz.do_jmp = 0;
+        m_malloc_free_epoch(1, 1);
+        TRACE(("dropbear_exit longjmped"))
+        /* dropbear_exit jumped here */
+    }
+
+    return 0;
+}
+
+int fuzz_run_client(const uint8_t *Data, size_t Size, int skip_kexmaths) {
+    static int once = 0;
+    if (!once) {
+        fuzz_cli_setup();
+        fuzz.skip_kexmaths = skip_kexmaths;
+        once = 1;
+    }
+
+    if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+        return 0;
+    }
+
+    // Allow to proceed sooner
+    ses.kexstate.donefirstkex = 1;
+
+    uint32_t wrapseed;
+    genrandom((void*)&wrapseed, sizeof(wrapseed));
+    wrapfd_setseed(wrapseed);
+
+    int fakesock = wrapfd_new_fuzzinput();
+
+    m_malloc_set_epoch(1);
+    fuzz.do_jmp = 1;
+    if (setjmp(fuzz.jmp) == 0) {
+        cli_session(fakesock, fakesock, NULL, 0);
+        m_malloc_free_epoch(1, 0);
+    } else {
+        fuzz.do_jmp = 0;
+        m_malloc_free_epoch(1, 1);
+        TRACE(("dropbear_exit longjmped"))
+        /* dropbear_exit jumped here */
+    }
+
+    return 0;
+}
+
+const void* fuzz_get_algo(const algo_type *algos, const char* name) {
+    const algo_type *t;
+    for (t = algos; t->name; t++) {
+        if (strcmp(t->name, name) == 0) {
+            return t->data;
+        }
+    }
+    assert(0);
+}
+
+void fuzz_dump(const unsigned char* data, size_t len) {
+    if (fuzz.dumping) {
+        TRACE(("dump %zu", len))
+        assert(atomicio(vwrite, fuzz.recv_dumpfd, (void*)data, len) == len);
+    }
+}
+
+static struct passwd pwd_root = {
+    .pw_name = "root",
+    .pw_passwd = "!",
+    .pw_uid = 0,
+    .pw_gid = 0,
+    .pw_dir = "/root",
+    .pw_shell = "/bin/sh",
+};
+
+static struct passwd pwd_other = {
+    .pw_name = "other",
+    .pw_passwd = "!",
+    .pw_uid = 100,
+    .pw_gid = 100,
+    .pw_dir = "/home/other",
+    .pw_shell = "/bin/sh",
+};
+
+
+/* oss-fuzz runs fuzzers under minijail, without /etc/passwd.
+We provide sufficient values for the fuzzers to run */
+struct passwd* fuzz_getpwnam(const char *login) {
+    if (!fuzz.fuzzing) {
+        return getpwnam(login);
+    }
+    if (strcmp(login, pwd_other.pw_name) == 0) {
+        return &pwd_other;
+    }
+    if (strcmp(login, pwd_root.pw_name) == 0) {
+        return &pwd_root;
+    }
+    return NULL;
+}
+
+struct passwd* fuzz_getpwuid(uid_t uid) {
+    if (!fuzz.fuzzing) {
+        return getpwuid(uid);
+    }
+    if (uid == pwd_other.pw_uid) {
+        return &pwd_other;
+    }
+    if (uid == pwd_root.pw_uid) {
+        return &pwd_root;
+    }
+    return NULL;
+}
+

fuzz/fuzz-harness.c

@@ -0,0 +1,66 @@
+#include "includes.h"
+#include "buffer.h"
+#include "dbutil.h"
+
+extern int LLVMFuzzerTestOneInput(const unsigned char *data, size_t size);
+
+int main(int argc, char ** argv) {
+    int i;
+    buffer *input = buf_new(100000);
+    int quiet = 0;
+
+    for (i = 1; i < argc; i++) {
+#if DEBUG_TRACE
+        if (strcmp(argv[i], "-v") == 0) {
+            debug_trace = 1;
+            TRACE(("debug printing on"))
+        }
+#endif
+        if (strcmp(argv[i], "-q") == 0) {
+            printf("Running quiet\n");
+            quiet = 1;
+        }
+    }
+
+    int old_fuzz_wrapfds = 0;
+    for (i = 1; i < argc; i++) {
+        if (argv[i][0] == '-') {
+            /* ignore arguments */
+            continue;
+        }
+
+        char* fn = argv[i];
+        buf_setlen(input, 0);
+        buf_readfile(input, fn);
+        buf_setpos(input, 0);
+
+		/* Run twice to catch problems with statefulness */
+        fuzz.wrapfds = old_fuzz_wrapfds;
+        if (!quiet) {
+            printf("Running %s once \n", fn);
+        }
+        LLVMFuzzerTestOneInput(input->data, input->len);
+        if (!quiet) {
+            printf("Running %s twice \n", fn);
+        }
+        LLVMFuzzerTestOneInput(input->data, input->len);
+        if (!quiet) {
+            printf("Done %s\n", fn);
+        }
+
+        /* Disable wrapfd so it won't interfere with buf_readfile() above */
+        old_fuzz_wrapfds = fuzz.wrapfds;
+        fuzz.wrapfds = 0;
+    }
+
+    printf("Finished\n");
+
+    return 0;
+}
+
+// Just to let it link
+size_t LLVMFuzzerMutate(uint8_t *UNUSED(Data), size_t UNUSED(Size), size_t UNUSED(MaxSize)) {
+    printf("standalone fuzzer harness shouldn't call LLVMFuzzerMutate");
+    abort();
+    return 0;
+}

fuzz/fuzz-hostkeys.c

@@ -0,0 +1,140 @@
+/* To be included in fuzz-common.c */
+
+static unsigned char keyr[] = {
+  0x00, 0x00, 0x00, 0x07, 0x73, 0x73, 0x68, 0x2d, 0x72, 0x73, 0x61, 0x00,
+  0x00, 0x00, 0x03, 0x01, 0x00, 0x01, 0x00, 0x00, 0x01, 0x01, 0x00, 0xb1,
+  0x06, 0x95, 0xc9, 0xa8, 0x38, 0xb9, 0x99, 0x91, 0xb5, 0x17, 0x39, 0xb9,
+  0xfa, 0xa4, 0x49, 0xf8, 0x2a, 0x4c, 0x14, 0xbd, 0xb6, 0x85, 0xdb, 0x38,
+  0x99, 0x44, 0xfa, 0xd6, 0xaa, 0x67, 0xef, 0x00, 0x75, 0x2b, 0x6a, 0x5c,
+  0x1b, 0x50, 0xa8, 0x52, 0xf9, 0xa7, 0xee, 0xe2, 0xb3, 0x80, 0x38, 0x92,
+  0x20, 0x86, 0x7c, 0xe5, 0x89, 0xb3, 0x06, 0xe4, 0x3b, 0xd1, 0xe2, 0x45,
+  0xea, 0xc1, 0xd5, 0x8e, 0x05, 0xfb, 0x90, 0x29, 0xd9, 0x41, 0xb3, 0x05,
+  0x31, 0x1e, 0xcc, 0xeb, 0x89, 0xdc, 0xd2, 0x6a, 0x99, 0x23, 0xbd, 0x7a,
+  0xbe, 0x8c, 0xe3, 0x3f, 0xa1, 0xe8, 0xf5, 0xb4, 0x51, 0x40, 0xb4, 0xb1,
+  0xc1, 0x16, 0x9f, 0x07, 0xbb, 0x99, 0xaa, 0x4b, 0x8f, 0x11, 0x19, 0x3c,
+  0x18, 0xbd, 0x6e, 0xce, 0x14, 0x54, 0x2c, 0x16, 0x4a, 0x5f, 0x89, 0xe4,
+  0x6b, 0x9f, 0x55, 0x68, 0xcc, 0x09, 0x8e, 0x4b, 0x92, 0xc8, 0x87, 0xfe,
+  0x09, 0xed, 0x53, 0x6e, 0xff, 0x5f, 0x15, 0x0d, 0x19, 0x9d, 0xa6, 0x54,
+  0xd2, 0xea, 0x59, 0x4f, 0xa1, 0x7c, 0xf6, 0xf5, 0x7f, 0x32, 0x23, 0xed,
+  0x72, 0xa8, 0x96, 0x17, 0x87, 0x06, 0xf2, 0xc7, 0xcd, 0xda, 0x4a, 0x10,
+  0xd1, 0xfd, 0xb8, 0xf1, 0xaf, 0x25, 0x55, 0x32, 0x45, 0x39, 0x95, 0xec,
+  0x0c, 0xa9, 0xf0, 0x47, 0x8b, 0x66, 0xe0, 0xb7, 0xa2, 0xf6, 0x35, 0x50,
+  0x27, 0xe7, 0x2f, 0x90, 0x35, 0x5b, 0xd5, 0x62, 0x19, 0xb4, 0x41, 0xd4,
+  0x52, 0xe7, 0x7f, 0x97, 0xfc, 0x5b, 0x4a, 0x5b, 0x19, 0x06, 0x65, 0x2d,
+  0x23, 0x29, 0x15, 0x8b, 0x05, 0xaf, 0xbe, 0xd3, 0x4a, 0x27, 0x5b, 0xc9,
+  0xc0, 0xd0, 0xd2, 0xba, 0x8b, 0x00, 0x7a, 0x2f, 0x39, 0xa0, 0x13, 0xb9,
+  0xe6, 0xf5, 0x4b, 0x21, 0x54, 0x57, 0xb3, 0xf9, 0x6c, 0x6f, 0xd0, 0x17,
+  0xf4, 0x50, 0x9d, 0x00, 0x00, 0x01, 0x00, 0x01, 0xf2, 0xda, 0x5f, 0xfb,
+  0xe2, 0xda, 0xfc, 0xe0, 0xdf, 0x3a, 0x0e, 0x14, 0x18, 0xc1, 0xd9, 0x1f,
+  0x43, 0xe3, 0x65, 0x3e, 0x07, 0xe7, 0x8d, 0xdc, 0x1d, 0x11, 0xc1, 0xd6,
+  0xc0, 0xd8, 0xda, 0x53, 0xf5, 0x04, 0x73, 0x51, 0x1b, 0x26, 0xef, 0x4e,
+  0xf5, 0xce, 0x3d, 0x77, 0x21, 0x94, 0xd0, 0xc7, 0xc1, 0xda, 0x19, 0x7d,
+  0xf8, 0xc5, 0x4c, 0xc8, 0xee, 0x7d, 0xd1, 0xbb, 0x02, 0x90, 0x2b, 0xff,
+  0x4e, 0x4d, 0xd7, 0x9d, 0x72, 0x0c, 0x60, 0x0f, 0x4b, 0x83, 0xf5, 0xc2,
+  0x26, 0xd6, 0x22, 0xb8, 0x60, 0x3a, 0xf9, 0x2f, 0x92, 0x2a, 0x2e, 0x14,
+  0xa7, 0x56, 0x1c, 0x56, 0x05, 0x41, 0x92, 0xac, 0xb1, 0x4e, 0x44, 0x1e,
+  0x70, 0x42, 0xda, 0xc7, 0xc8, 0x9c, 0xae, 0x29, 0x2d, 0x0c, 0x3a, 0xff,
+  0x9b, 0xb6, 0xad, 0xb4, 0xfb, 0x49, 0x28, 0x96, 0x74, 0xf5, 0x94, 0x74,
+  0xb7, 0x40, 0x93, 0x2b, 0x34, 0x29, 0xd2, 0x8a, 0xf3, 0x99, 0xf9, 0xe9,
+  0xd8, 0xcc, 0x48, 0x1d, 0x3e, 0xc1, 0x82, 0x35, 0x4f, 0xef, 0xb1, 0x81,
+  0x3c, 0xe1, 0xa1, 0x03, 0x65, 0xac, 0x21, 0x21, 0x40, 0x61, 0xfb, 0xd3,
+  0x54, 0xac, 0xa1, 0xf2, 0xf0, 0x61, 0xd9, 0x01, 0x4e, 0xc2, 0x28, 0xb1,
+  0x7c, 0x27, 0x6e, 0x56, 0x68, 0x69, 0x8f, 0xc5, 0xfd, 0xca, 0x39, 0x6e,
+  0x22, 0x09, 0xf1, 0xb4, 0xd5, 0xac, 0xb8, 0xe0, 0x1b, 0x21, 0x86, 0xf4,
+  0xc8, 0x15, 0xc6, 0x1f, 0x21, 0xae, 0xcb, 0xab, 0x5a, 0x09, 0x30, 0x9e,
+  0xdd, 0x6c, 0x38, 0x59, 0xec, 0x59, 0x3a, 0x08, 0xee, 0x46, 0x7b, 0x78,
+  0x23, 0xbc, 0xfc, 0xe2, 0xda, 0xe8, 0x1a, 0x65, 0xe6, 0xe0, 0x78, 0xd3,
+  0xb0, 0x03, 0x2e, 0xf1, 0xb8, 0xca, 0x8e, 0x90, 0x75, 0xaf, 0xf7, 0xa8,
+  0x48, 0xed, 0x82, 0xc9, 0xcf, 0x44, 0x56, 0xfc, 0x05, 0xfd, 0x6b, 0x00,
+  0x00, 0x00, 0x81, 0x00, 0xfc, 0x94, 0xdf, 0x42, 0xc7, 0x9a, 0xa2, 0xff,
+  0x32, 0xdf, 0x06, 0xb6, 0x4d, 0x90, 0x31, 0x28, 0x28, 0xdb, 0x03, 0xf9,
+  0xa6, 0xb3, 0xa2, 0x91, 0x4c, 0xdf, 0x6e, 0xf6, 0xb9, 0x44, 0x3b, 0xdd,
+  0x17, 0xc1, 0xc8, 0x1d, 0xd1, 0xc0, 0xc0, 0x30, 0x22, 0xbe, 0x24, 0x2e,
+  0x0e, 0xdf, 0xe0, 0x18, 0x37, 0x3e, 0xb8, 0x7f, 0xb2, 0x50, 0x34, 0xc4,
+  0x08, 0x5e, 0x69, 0x1f, 0xd5, 0xc9, 0xce, 0x47, 0x7d, 0x75, 0x5e, 0x3b,
+  0x87, 0xdd, 0x46, 0x35, 0x01, 0x0f, 0x17, 0x8a, 0xf1, 0xf1, 0xc4, 0xa9,
+  0x94, 0xa7, 0x6e, 0xce, 0x80, 0xe3, 0x17, 0x2e, 0xb0, 0xef, 0x63, 0xa7,
+  0x11, 0x86, 0x96, 0x4a, 0x63, 0x2d, 0x9e, 0x92, 0x62, 0x43, 0x43, 0x72,
+  0xa5, 0xdc, 0xa0, 0xcd, 0x19, 0x93, 0xd7, 0xe0, 0x80, 0x41, 0x27, 0xea,
+  0xe4, 0xe8, 0xc1, 0x91, 0x9e, 0x13, 0xb3, 0x9c, 0xd1, 0xed, 0xcb, 0xbf,
+  0x00, 0x00, 0x00, 0x81, 0x00, 0xb3, 0x6b, 0xee, 0xa4, 0x70, 0x4e, 0xfb,
+  0xf9, 0x7e, 0x2e, 0x74, 0x5d, 0x3e, 0x8b, 0x3f, 0xff, 0x8c, 0xde, 0x68,
+  0x38, 0xda, 0xce, 0xc0, 0x66, 0x4b, 0xca, 0x35, 0xc3, 0x97, 0xa8, 0xf0,
+  0x00, 0x8e, 0xb3, 0x46, 0x60, 0xd0, 0x4d, 0x7e, 0x7b, 0xdf, 0x17, 0x7b,
+  0x2f, 0xc4, 0x16, 0xee, 0x45, 0xdb, 0xa5, 0x5d, 0xc0, 0x72, 0xe9, 0xc6,
+  0x91, 0x0f, 0xd9, 0x30, 0x74, 0x6c, 0xde, 0x93, 0xb5, 0xb6, 0xaf, 0x52,
+  0x53, 0x3c, 0x08, 0x55, 0xea, 0xb8, 0x66, 0x07, 0xbe, 0xce, 0xf9, 0x80,
+  0x8d, 0xe0, 0xca, 0xdc, 0x63, 0xe8, 0x58, 0x94, 0x22, 0x4f, 0x08, 0x66,
+  0x13, 0x9e, 0x63, 0x2e, 0x92, 0x7a, 0xb6, 0x66, 0x94, 0x9b, 0x71, 0x66,
+  0xd3, 0x08, 0xc9, 0x89, 0xea, 0x78, 0x35, 0x0d, 0xf2, 0x25, 0x55, 0xd4,
+  0xb0, 0x9b, 0xea, 0x18, 0x77, 0xf6, 0x25, 0x02, 0xb4, 0x5e, 0x71, 0xea,
+  0xa3
+};
+static unsigned int keyr_len = 805;
+static unsigned char keye[] = {
+  0x00, 0x00, 0x00, 0x13, 0x65, 0x63, 0x64, 0x73, 0x61, 0x2d, 0x73, 0x68,
+  0x61, 0x32, 0x2d, 0x6e, 0x69, 0x73, 0x74, 0x70, 0x32, 0x35, 0x36, 0x00,
+  0x00, 0x00, 0x08, 0x6e, 0x69, 0x73, 0x74, 0x70, 0x32, 0x35, 0x36, 0x00,
+  0x00, 0x00, 0x41, 0x04, 0x0a, 0x00, 0x6c, 0x7c, 0x1c, 0xc4, 0x03, 0x44,
+  0x46, 0x70, 0xba, 0x00, 0x7c, 0x79, 0x89, 0x7b, 0xc3, 0xd6, 0x32, 0x98,
+  0x34, 0xe7, 0x1c, 0x60, 0x04, 0x73, 0xd9, 0xb5, 0x7e, 0x94, 0x04, 0x04,
+  0xea, 0xc8, 0xb8, 0xfb, 0xd4, 0x70, 0x9f, 0x29, 0xa7, 0x8d, 0x9a, 0x64,
+  0x3a, 0x8c, 0x45, 0x23, 0x37, 0x5a, 0x2b, 0x4f, 0x54, 0x91, 0x80, 0xf1,
+  0xac, 0x3a, 0xf5, 0x6d, 0xfa, 0xe8, 0x76, 0x20, 0x00, 0x00, 0x00, 0x21,
+  0x00, 0xc2, 0xaf, 0xbe, 0xdc, 0x06, 0xff, 0x3d, 0x08, 0x9b, 0x73, 0xe0,
+  0x3c, 0x58, 0x28, 0x70, 0x9b, 0x23, 0x39, 0x51, 0xd7, 0xbc, 0xa7, 0x1a,
+  0xf5, 0xb4, 0x23, 0xd3, 0xf6, 0x17, 0xa6, 0x9c, 0x02
+};
+static unsigned int keye_len = 141;
+static unsigned char keyd[] = {
+  0x00, 0x00, 0x00, 0x07, 0x73, 0x73, 0x68, 0x2d, 0x64, 0x73, 0x73, 0x00,
+  0x00, 0x00, 0x81, 0x00, 0xb0, 0x02, 0x19, 0x8b, 0xf3, 0x46, 0xf9, 0xc5,
+  0x47, 0x78, 0x3d, 0x7f, 0x04, 0x10, 0x0a, 0x43, 0x8e, 0x00, 0x9e, 0xa4,
+  0x30, 0xfd, 0x47, 0xb9, 0x05, 0x9e, 0x95, 0xaa, 0x37, 0x9a, 0x91, 0xbf,
+  0xf8, 0xb9, 0xe0, 0x8d, 0x97, 0x49, 0x87, 0xe2, 0xe6, 0x90, 0xc1, 0xe4,
+  0x61, 0x57, 0x77, 0xfd, 0x91, 0x1d, 0xe1, 0x4b, 0xa0, 0xb2, 0xbc, 0xa1,
+  0x6a, 0x6a, 0xdd, 0x31, 0xda, 0xe7, 0x54, 0x03, 0xfd, 0x48, 0x62, 0x8a,
+  0x1d, 0x1d, 0xe2, 0x26, 0x76, 0x29, 0x08, 0xab, 0x65, 0x88, 0x74, 0x02,
+  0x1e, 0xa9, 0x29, 0x1b, 0x69, 0x3b, 0xb4, 0x5f, 0x62, 0x80, 0xa3, 0xa6,
+  0x4b, 0xc3, 0x0e, 0x89, 0x24, 0xe4, 0x8a, 0x31, 0xae, 0x89, 0x7a, 0x7a,
+  0x58, 0x44, 0x46, 0x77, 0x62, 0x33, 0xa2, 0x5d, 0x17, 0x0e, 0x0b, 0x64,
+  0xee, 0x1a, 0x02, 0xbd, 0xf8, 0x27, 0x86, 0xe1, 0x87, 0x92, 0x84, 0xc7,
+  0x00, 0x00, 0x00, 0x15, 0x00, 0xb3, 0x8b, 0x81, 0x39, 0x9c, 0xba, 0xe1,
+  0x1d, 0x9a, 0x8b, 0x89, 0xb3, 0x08, 0x9b, 0x12, 0xa8, 0x7b, 0xea, 0x25,
+  0x8d, 0x00, 0x00, 0x00, 0x80, 0x76, 0x3f, 0x72, 0xb2, 0xef, 0xc3, 0x16,
+  0xd8, 0x09, 0x36, 0x23, 0x03, 0xf9, 0x5c, 0xac, 0x8b, 0x51, 0x35, 0x2e,
+  0x36, 0xba, 0x39, 0xd0, 0x57, 0x19, 0x4f, 0x14, 0x8b, 0xea, 0x32, 0xfc,
+  0x86, 0x41, 0xea, 0x85, 0x71, 0x4d, 0x52, 0x0c, 0xff, 0xc1, 0xd3, 0xd5,
+  0xcd, 0x2e, 0x37, 0xcc, 0xe1, 0xcc, 0x22, 0x38, 0xa8, 0x47, 0x16, 0x34,
+  0x3b, 0x32, 0x9c, 0x2f, 0x0f, 0xcd, 0x5f, 0x7f, 0x06, 0x64, 0x89, 0xc5,
+  0x02, 0x4f, 0x9a, 0x70, 0x11, 0xf0, 0xaa, 0xe1, 0x7a, 0x75, 0x49, 0x8d,
+  0x0f, 0x8d, 0x5b, 0x54, 0xe2, 0xe7, 0x10, 0x6e, 0xe5, 0xbd, 0xb7, 0x62,
+  0xf7, 0x40, 0x59, 0x39, 0x31, 0xd9, 0x13, 0x7b, 0xa3, 0xdf, 0x0d, 0x31,
+  0x52, 0x43, 0xe0, 0xaf, 0x19, 0x12, 0x15, 0x12, 0x34, 0x01, 0x6f, 0xcf,
+  0x62, 0x21, 0xe4, 0xc8, 0x34, 0x69, 0xc9, 0x85, 0xe3, 0xde, 0xd7, 0x0c,
+  0xac, 0x00, 0x00, 0x00, 0x80, 0x41, 0xa3, 0xc5, 0xa4, 0x89, 0x86, 0xc8,
+  0x17, 0xf3, 0x8e, 0x68, 0x72, 0xbe, 0x13, 0x8b, 0x63, 0xe3, 0x07, 0xe3,
+  0xd5, 0xa4, 0xa2, 0xd3, 0x2c, 0x2f, 0xbe, 0x16, 0x71, 0xc9, 0x79, 0x64,
+  0x5a, 0x1e, 0x19, 0x82, 0x07, 0xe2, 0x93, 0xda, 0x22, 0xcf, 0x6d, 0xdd,
+  0x38, 0xcb, 0x6e, 0x6b, 0x0f, 0x95, 0x8d, 0xfa, 0x3f, 0xbb, 0xb8, 0x6a,
+  0x7d, 0xc3, 0x22, 0x1e, 0x49, 0xcf, 0x98, 0x73, 0x05, 0x5d, 0x97, 0xfa,
+  0x4c, 0xf2, 0x82, 0x3d, 0x98, 0x61, 0x4e, 0x96, 0x80, 0x26, 0x79, 0xda,
+  0x24, 0xf8, 0xa1, 0x9c, 0x71, 0x82, 0xe6, 0xc7, 0xdc, 0xc2, 0xa5, 0xd0,
+  0xf4, 0x36, 0xba, 0xaa, 0xee, 0xd3, 0x43, 0x46, 0x1d, 0xaa, 0x53, 0xea,
+  0x85, 0x2c, 0x1b, 0xc8, 0x7c, 0x3c, 0xe7, 0x06, 0x44, 0xab, 0x16, 0xad,
+  0xc6, 0x54, 0x91, 0x9a, 0xb9, 0xc0, 0xeb, 0x93, 0x8c, 0xca, 0x39, 0xcf,
+  0x6f, 0x00, 0x00, 0x00, 0x15, 0x00, 0x90, 0x26, 0x0a, 0xfc, 0x15, 0x99,
+  0x7b, 0xac, 0xaa, 0x0c, 0xa2, 0xca, 0x7b, 0xa8, 0xd4, 0xdf, 0x68, 0x56,
+  0xf9, 0x39
+};
+static unsigned int keyd_len = 458;
+static unsigned char keyed25519[] = {
+  0x00, 0x00, 0x00, 0x0b, 0x73, 0x73, 0x68, 0x2d, 0x65, 0x64, 0x32, 0x35,
+  0x35, 0x31, 0x39, 0x00, 0x00, 0x00, 0x40, 0x10, 0xb3, 0x79, 0x06, 0xe5,
+  0x9b, 0xe7, 0xe4, 0x6e, 0xec, 0xfe, 0xa5, 0x39, 0x21, 0x7c, 0xf6, 0x66,
+  0x8c, 0x0b, 0x6a, 0x01, 0x09, 0x05, 0xc7, 0x4f, 0x64, 0xa8, 0x24, 0xd2,
+  0x8d, 0xbd, 0xdd, 0xc6, 0x3c, 0x99, 0x1b, 0x2d, 0x3e, 0x33, 0x90, 0x19,
+  0xa4, 0xd5, 0xe9, 0x23, 0xfe, 0x8e, 0xd6, 0xd4, 0xf9, 0xb1, 0x11, 0x69,
+  0x7c, 0x57, 0x52, 0x0e, 0x41, 0xdb, 0x1b, 0x12, 0x87, 0xfa, 0xc9
+};
+static unsigned int keyed25519_len = 83;

fuzz/fuzz-sshpacketmutator.c

@@ -0,0 +1,306 @@
+/* A mutator/crossover for SSH protocol streams.
+   Attempts to mutate each SSH packet individually, keeping
+   lengths intact.
+   It will prepend a SSH-2.0-dbfuzz\r\n version string.
+
+   Linking this file to a binary will make libfuzzer pick up the custom mutator.
+
+   Care is taken to avoid memory allocation which would otherwise
+   slow exec/s substantially */
+
+#include "fuzz.h"
+#include "dbutil.h"
+
+size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize);
+
+static const char* FIXED_VERSION = "SSH-2.0-dbfuzz\r\n";
+static const char* FIXED_IGNORE_MSG = 
+        "\x00\x00\x00\x10\x06\x02\x00\x00\x00\x00\x11\x22\x33\x44\x55\x66";
+static const unsigned int FIXED_IGNORE_MSG_LEN = 16;
+#define MAX_FUZZ_PACKETS 500
+/* XXX This might need tuning */
+static const size_t MAX_OUT_SIZE = 50000;
+
+/* Splits packets from an input stream buffer "inp".
+The initial SSH version identifier is discarded.
+If packets are not recognised it will increment until an uint32 of valid
+packet length is found. */
+
+/* out_packets an array of num_out_packets*buffer, each of size RECV_MAX_PACKET_LEN */
+static void fuzz_get_packets(buffer *inp, buffer **out_packets, unsigned int *num_out_packets) {
+    /* Skip any existing banner. Format is
+          SSH-protoversion-softwareversion SP comments CR LF
+    so we look for SSH-2. then a subsequent LF */
+    unsigned char* version = memmem(inp->data, inp->len, "SSH-2.", strlen("SSH-2."));
+    if (version) {
+        buf_incrpos(inp, version - inp->data);
+        unsigned char* newline = memchr(&inp->data[inp->pos], '\n', inp->len - inp->pos);
+        if (newline) {
+            buf_incrpos(inp, newline - &inp->data[inp->pos]+1);
+        } else {
+            /* Give up on any version string */
+            buf_setpos(inp, 0);
+        }
+    }
+
+    const unsigned int max_out_packets = *num_out_packets;
+    *num_out_packets = 0;
+    while (1) {
+        if (inp->pos + 4 > inp->len) {
+            /* End of input */
+            break;
+        }
+
+        if (*num_out_packets >= max_out_packets) {
+            /* End of output */
+            break;
+        }
+
+        /* Read packet */
+        unsigned int packet_len = buf_getint(inp);
+        if (packet_len > RECV_MAX_PACKET_LEN-4) {
+            /* Bad length, try skipping a single byte */
+            buf_decrpos(inp, 3);
+            continue;
+        }
+        packet_len = MIN(packet_len, inp->len - inp->pos);
+
+        /* Check the packet length makes sense */
+        if (packet_len >= MIN_PACKET_LEN-4) {
+            /* Copy to output buffer. We're reusing buffers */
+            buffer* new_packet = out_packets[*num_out_packets];
+            (*num_out_packets)++;
+            buf_setlen(new_packet, 0);
+            // packet_len doesn't include itself
+            buf_putint(new_packet, packet_len);
+            buf_putbytes(new_packet, buf_getptr(inp, packet_len), packet_len);
+        }
+        buf_incrpos(inp, packet_len);
+    }
+}
+
+/* Mutate a packet buffer in-place.
+Returns DROPBEAR_FAILURE if it's too short */
+static int buf_llvm_mutate(buffer *buf) {
+    int ret;
+    /* Position it after packet_length and padding_length */
+    const unsigned int offset = 5;
+    buf_setpos(buf, 0);
+    buf_incrwritepos(buf, offset);
+    size_t max_size = buf->size - buf->pos;
+    size_t new_size = LLVMFuzzerMutate(buf_getwriteptr(buf, max_size),
+        buf->len - buf->pos, max_size);
+    size_t new_total = new_size + 1 + 4;
+    // Round down to a block size
+    new_total = new_total - (new_total % dropbear_nocipher.blocksize);
+
+    if (new_total >= 16) {
+        buf_setlen(buf, new_total);
+        // Fix up the length fields
+        buf_setpos(buf, 0);
+        // packet_length doesn't include itself, does include padding_length byte
+        buf_putint(buf, new_size+1);
+        // always just put minimum padding length = 4
+        buf_putbyte(buf, 4);
+        ret = DROPBEAR_SUCCESS;
+    } else {
+        // instead put a fake packet
+        buf_setlen(buf, 0);
+        buf_putbytes(buf, FIXED_IGNORE_MSG, FIXED_IGNORE_MSG_LEN);
+        ret = DROPBEAR_FAILURE;
+    }
+    return ret;
+}
+
+
+/* Persistent buffers to avoid constant allocations */
+static buffer *oup;
+static buffer *alloc_packetA;
+static buffer *alloc_packetB;
+static buffer* packets1[MAX_FUZZ_PACKETS];
+static buffer* packets2[MAX_FUZZ_PACKETS];
+
+/* Allocate buffers once at startup.
+   'constructor' here so it runs before dbmalloc's interceptor */
+static void alloc_static_buffers() __attribute__((constructor));
+static void alloc_static_buffers() {
+
+    int i;
+    oup = buf_new(MAX_OUT_SIZE);
+    alloc_packetA = buf_new(RECV_MAX_PACKET_LEN);
+    alloc_packetB = buf_new(RECV_MAX_PACKET_LEN);
+
+    for (i = 0; i < MAX_FUZZ_PACKETS; i++) {
+        packets1[i] = buf_new(RECV_MAX_PACKET_LEN);
+    }
+    for (i = 0; i < MAX_FUZZ_PACKETS; i++) {
+        packets2[i] = buf_new(RECV_MAX_PACKET_LEN);
+    }
+}
+
+size_t LLVMFuzzerCustomMutator(uint8_t *Data, size_t Size,
+              size_t MaxSize, unsigned int Seed) {
+
+    buf_setlen(alloc_packetA, 0);
+    buf_setlen(alloc_packetB, 0);
+    buf_setlen(oup, 0);
+
+    unsigned int i;
+    size_t ret_len;
+    unsigned short randstate[3] = {0,0,0};
+    memcpy(randstate, &Seed, sizeof(Seed));
+
+    // printhex("mutator input", Data, Size);
+
+    /* 0.1% chance straight llvm mutate */
+    // if (nrand48(randstate) % 1000 == 0) {
+    //     ret_len = LLVMFuzzerMutate(Data, Size, MaxSize);
+    //     // printhex("mutator straight llvm", Data, ret_len);
+    //     return ret_len;
+    // }
+
+    buffer inp_buf = {.data = Data, .size = Size, .len = Size, .pos = 0};
+    buffer *inp = &inp_buf;
+
+    /* Parse packets */
+    unsigned int num_packets = MAX_FUZZ_PACKETS;
+    buffer **packets = packets1;
+    fuzz_get_packets(inp, packets, &num_packets);
+
+    if (num_packets == 0) {
+        // Make up a packet, writing direct to the buffer
+        inp->size = MaxSize;
+        buf_setlen(inp, 0);
+        buf_putbytes(inp, FIXED_VERSION, strlen(FIXED_VERSION));
+        buf_putbytes(inp, FIXED_IGNORE_MSG, FIXED_IGNORE_MSG_LEN);
+        // printhex("mutator no input", Data, inp->len);
+        return inp->len;
+    }
+
+    /* Start output */
+    /* Put a new banner to output */
+    buf_putbytes(oup, FIXED_VERSION, strlen(FIXED_VERSION));
+
+    /* Iterate output */
+    for (i = 0; i < num_packets+1; i++) {
+        // These are pointers to output
+        buffer *out_packetA = NULL, *out_packetB = NULL;
+        buf_setlen(alloc_packetA, 0);
+        buf_setlen(alloc_packetB, 0);
+
+        /* 2% chance each */
+        const int optA = nrand48(randstate) % 50;
+        if (optA == 0) {
+            /* Copy another */
+            unsigned int other = nrand48(randstate) % num_packets;
+            out_packetA = packets[other];
+            // printf("copy another %d / %d len %u\n", other, num_packets, out_packetA->len);
+        }
+        if (optA == 1) {
+            /* Mutate another */
+            unsigned int other = nrand48(randstate) % num_packets;
+            out_packetA = alloc_packetA;
+            buffer *from = packets[other];
+            buf_putbytes(out_packetA, from->data, from->len);
+            if (buf_llvm_mutate(out_packetA) == DROPBEAR_FAILURE) {
+                out_packetA = NULL;
+            }
+            // printf("mutate another %d / %d len %u -> %u\n", other, num_packets, from->len, out_packetA->len);
+        }
+
+        if (i < num_packets) {
+            int optB = nrand48(randstate) % 100;
+            if (optB == 1) {
+                /* small chance of drop */
+                /* Drop it */
+                //printf("%d drop\n", i);
+            } else { 
+                /* Odds of modification are proportional to packet position.
+                First packet has 20% chance, last has 100% chance */
+                int optC = nrand48(randstate) % 1000;
+                int mutate_cutoff = MAX(200, (1000 * (i+1) / num_packets));
+                if (optC < mutate_cutoff) {
+                    // // printf("%d mutate\n", i);
+                    out_packetB = alloc_packetB;
+                    buffer *from = packets[i];
+                    buf_putbytes(out_packetB, from->data, from->len);
+                    if (buf_llvm_mutate(out_packetB) == DROPBEAR_FAILURE) {
+                        out_packetB = from;
+                    }
+                    // printf("mutate self %d / %d len %u -> %u\n", i, num_packets, from->len, out_packetB->len);
+                } else {
+                    /* Copy as-is */
+                    out_packetB = packets[i];
+                    // printf("%d as-is len %u\n", i, out_packetB->len);
+                } 
+            }
+        }
+
+        if (out_packetA && oup->len + out_packetA->len <= oup->size) {
+            buf_putbytes(oup, out_packetA->data, out_packetA->len);
+        }
+        if (out_packetB && oup->len + out_packetB->len <= oup->size) {
+            buf_putbytes(oup, out_packetB->data, out_packetB->len);
+        }
+    }
+
+    ret_len = MIN(MaxSize, oup->len);
+    memcpy(Data, oup->data, ret_len);
+    // printhex("mutator done", Data, ret_len);
+    return ret_len;
+}
+
+size_t LLVMFuzzerCustomCrossOver(const uint8_t *Data1, size_t Size1,
+                                            const uint8_t *Data2, size_t Size2,
+                                            uint8_t *Out, size_t MaxOutSize,
+                                            unsigned int Seed) {
+    unsigned short randstate[3] = {0,0,0};
+    memcpy(randstate, &Seed, sizeof(Seed));
+
+    unsigned int i;
+    buffer inp_buf1 = {.data = (void*)Data1, .size = Size1, .len = Size1, .pos = 0};
+    buffer *inp1 = &inp_buf1;
+    buffer inp_buf2 = {.data = (void*)Data2, .size = Size2, .len = Size2, .pos = 0};
+    buffer *inp2 = &inp_buf2;
+
+    unsigned int num_packets1 = MAX_FUZZ_PACKETS;
+    fuzz_get_packets(inp1, packets1, &num_packets1);
+    unsigned int num_packets2 = MAX_FUZZ_PACKETS;
+    fuzz_get_packets(inp2, packets2, &num_packets2);
+
+    // fprintf(stderr, "input 1 %u packets\n", num_packets1);
+    // printhex("crossover input1", Data1, Size1);
+    // fprintf(stderr, "input 2 %u packets\n", num_packets2);
+    // printhex("crossover input2", Data2, Size2);
+
+    buf_setlen(oup, 0);
+    /* Put a new banner to output */
+    buf_putbytes(oup, FIXED_VERSION, strlen(FIXED_VERSION));
+
+    if (num_packets1 == 0 && num_packets2 == 0) {
+        buf_putbytes(oup, FIXED_IGNORE_MSG, FIXED_IGNORE_MSG_LEN);
+    } else {
+        unsigned int min_out = MIN(num_packets1, num_packets2);
+        unsigned int max_out = num_packets1 + num_packets2;
+        unsigned int num_out = min_out + nrand48(randstate) % (max_out-min_out+1);
+
+        for (i = 0; i < num_out; i++) {
+            unsigned int choose = nrand48(randstate) % (num_packets1 + num_packets2);
+            buffer *p = NULL;
+            if (choose < num_packets1) {
+                p = packets1[choose];
+            } else {
+                p = packets2[choose-num_packets1];
+            }
+            if (oup->len + p->len <= oup->size) {
+                buf_putbytes(oup, p->data, p->len);
+            }
+        }
+    }
+
+    size_t ret_len = MIN(MaxOutSize, oup->len);
+    memcpy(Out, oup->data, ret_len);
+    // printhex("crossover output", Out, ret_len);
+    return ret_len;
+}
+

fuzz/fuzz-wrapfd.c

@@ -0,0 +1,279 @@
+#define FUZZ_SKIP_WRAP 1
+#include "includes.h"
+#include "fuzz-wrapfd.h"
+
+#include "dbutil.h"
+
+#include "fuzz.h"
+
+#define IOWRAP_MAXFD (FD_SETSIZE-1)
+static const int MAX_RANDOM_IN = 50000;
+static const double CHANCE_CLOSE = 1.0 / 600;
+static const double CHANCE_INTR = 1.0 / 900;
+static const double CHANCE_READ1 = 0.96;
+static const double CHANCE_READ2 = 0.5;
+static const double CHANCE_WRITE1 = 0.96;
+static const double CHANCE_WRITE2 = 0.5;
+
+struct fdwrap {
+	enum wrapfd_mode mode;
+	int closein;
+	int closeout;
+};
+
+static struct fdwrap wrap_fds[IOWRAP_MAXFD+1] = {{UNUSED, 0, 0}};
+static int wrapfd_maxfd = -1;
+static unsigned short rand_state[3];
+static buffer *input_buf;
+static int devnull_fd = -1;
+
+static void wrapfd_remove(int fd);
+
+void wrapfd_setup(buffer *buf) {
+	TRACE(("wrapfd_setup"))
+
+	// clean old ones
+	int i;
+	for (i = 0; i <= wrapfd_maxfd; i++) {
+		if (wrap_fds[i].mode != UNUSED) {
+			wrapfd_remove(i);
+		}
+	}
+	wrapfd_maxfd = -1;
+
+	memset(rand_state, 0x0, sizeof(rand_state));
+	wrapfd_setseed(50);
+	input_buf = buf;
+}
+
+void wrapfd_setseed(uint32_t seed) {
+	memcpy(rand_state, &seed, sizeof(seed));
+	nrand48(rand_state);
+}
+
+int wrapfd_new_fuzzinput() {
+	if (devnull_fd == -1) {
+		devnull_fd = open("/dev/null", O_RDONLY);
+		assert(devnull_fd != -1);
+	}
+
+	int fd = dup(devnull_fd);
+	assert(fd != -1);
+	assert(wrap_fds[fd].mode == UNUSED);
+	wrap_fds[fd].mode = COMMONBUF;
+	wrap_fds[fd].closein = 0;
+	wrap_fds[fd].closeout = 0;
+	wrapfd_maxfd = MAX(fd, wrapfd_maxfd);
+
+	return fd;
+}
+
+int wrapfd_new_dummy() {
+	if (devnull_fd == -1) {
+		devnull_fd = open("/dev/null", O_RDONLY);
+		assert(devnull_fd != -1);
+	}
+
+	int fd = dup(devnull_fd);
+	if (fd == -1) {
+		return -1;
+	}
+	if (fd > IOWRAP_MAXFD) {
+		close(fd);
+		errno = EMFILE;
+		return -1;
+	}
+	assert(wrap_fds[fd].mode == UNUSED);
+	wrap_fds[fd].mode = DUMMY;
+	wrap_fds[fd].closein = 0;
+	wrap_fds[fd].closeout = 0;
+	wrapfd_maxfd = MAX(fd, wrapfd_maxfd);
+
+	return fd;
+}
+
+
+static void wrapfd_remove(int fd) {
+	TRACE(("wrapfd_remove %d", fd))
+	assert(fd >= 0);
+	assert(fd <= IOWRAP_MAXFD);
+	assert(wrap_fds[fd].mode != UNUSED);
+	wrap_fds[fd].mode = UNUSED;
+	close(fd);
+}
+
+int wrapfd_close(int fd) {
+	if (fd >= 0 && fd <= IOWRAP_MAXFD && wrap_fds[fd].mode != UNUSED) {
+		wrapfd_remove(fd);
+		return 0;
+	} else {
+		return close(fd);
+	}
+}
+
+int wrapfd_read(int fd, void *out, size_t count) {
+	size_t maxread;
+
+	if (!fuzz.wrapfds) {
+		return read(fd, out, count);
+	}
+
+	if (fd < 0 || fd > IOWRAP_MAXFD || wrap_fds[fd].mode == UNUSED) {
+		/* XXX - assertion failure? */
+		TRACE(("Bad read descriptor %d\n", fd))
+		errno = EBADF;
+		return -1;
+	}
+
+	assert(count != 0);
+
+	if (wrap_fds[fd].closein || erand48(rand_state) < CHANCE_CLOSE) {
+		wrap_fds[fd].closein = 1;
+		errno = ECONNRESET;
+		return -1;
+	}
+
+	if (erand48(rand_state) < CHANCE_INTR) {
+		errno = EINTR;
+		return -1;
+	}
+
+	if (input_buf && wrap_fds[fd].mode == COMMONBUF) {
+		maxread = MIN(input_buf->len - input_buf->pos, count);
+		/* returns 0 if buf is EOF, as intended */
+		if (maxread > 0) {
+			maxread = nrand48(rand_state) % maxread + 1;
+		}
+		memcpy(out, buf_getptr(input_buf, maxread), maxread);
+		buf_incrpos(input_buf, maxread);
+		return maxread;
+	}
+
+	// return fixed output, of random length
+	maxread = MIN(MAX_RANDOM_IN, count);
+	maxread = nrand48(rand_state) % maxread + 1;
+	memset(out, 0xef, maxread);
+	return maxread;
+}
+
+int wrapfd_write(int fd, const void* in, size_t count) {
+	unsigned const volatile char* volin = in;
+	unsigned int i;
+
+	if (!fuzz.wrapfds) {
+		return write(fd, in, count);
+	}
+
+	if (fd < 0 || fd > IOWRAP_MAXFD || wrap_fds[fd].mode == UNUSED) {
+		/* XXX - assertion failure? */
+		TRACE(("Bad read descriptor %d\n", fd))
+		errno = EBADF;
+		return -1;
+	}
+
+	assert(count != 0);
+
+	/* force read to exercise sanitisers */
+	for (i = 0; i < count; i++) {
+		(void)volin[i];
+	}
+
+	if (wrap_fds[fd].closeout || erand48(rand_state) < CHANCE_CLOSE) {
+		wrap_fds[fd].closeout = 1;
+		errno = ECONNRESET;
+		return -1;
+	}
+
+	if (erand48(rand_state) < CHANCE_INTR) {
+		errno = EINTR;
+		return -1;
+	}
+
+	return nrand48(rand_state) % (count+1);
+}
+
+int wrapfd_select(int nfds, fd_set *readfds, fd_set *writefds, 
+	fd_set *exceptfds, struct timeval *timeout) {
+	int i, nset, sel;
+	int ret = 0;
+	int fdlist[IOWRAP_MAXFD+1];
+
+	if (!fuzz.wrapfds) {
+		return select(nfds, readfds, writefds, exceptfds, timeout);
+	}
+
+	assert(nfds <= IOWRAP_MAXFD+1);
+
+	if (erand48(rand_state) < CHANCE_INTR) {
+		errno = EINTR;
+		return -1;
+	}
+
+	/* read */
+	if (readfds != NULL && erand48(rand_state) < CHANCE_READ1) {
+		for (i = 0, nset = 0; i < nfds; i++) {
+			if (FD_ISSET(i, readfds)) {
+				assert(wrap_fds[i].mode != UNUSED);
+				fdlist[nset] = i;
+				nset++;
+			}
+		}
+		DROPBEAR_FD_ZERO(readfds);
+
+		if (nset > 0) {
+			/* set one */
+			sel = fdlist[nrand48(rand_state) % nset];
+			FD_SET(sel, readfds);
+			ret++;
+
+			if (erand48(rand_state) < CHANCE_READ2) {
+				sel = fdlist[nrand48(rand_state) % nset];
+				if (!FD_ISSET(sel, readfds)) {
+					FD_SET(sel, readfds);
+					ret++;
+				}
+			}
+		}
+	}
+
+	/* write */
+	if (writefds != NULL && erand48(rand_state) < CHANCE_WRITE1) {
+		for (i = 0, nset = 0; i < nfds; i++) {
+			if (FD_ISSET(i, writefds)) {
+				assert(wrap_fds[i].mode != UNUSED);
+				fdlist[nset] = i;
+				nset++;
+			}
+		}
+		DROPBEAR_FD_ZERO(writefds);
+
+		/* set one */
+		if (nset > 0) {
+			sel = fdlist[nrand48(rand_state) % nset];
+			FD_SET(sel, writefds);
+			ret++;
+
+			if (erand48(rand_state) < CHANCE_WRITE2) {
+				sel = fdlist[nrand48(rand_state) % nset];
+				if (!FD_ISSET(sel, writefds)) {
+					FD_SET(sel, writefds);
+					ret++;
+				}
+			}
+		}
+	}
+	return ret;
+}
+
+int fuzz_kill(pid_t pid, int sig) {
+	if (fuzz.fuzzing) {
+		TRACE(("fuzz_kill ignoring pid %d signal %d", (pid), sig))
+		if (sig >= 0) {
+			return 0;
+		} else {
+			errno = EINVAL;
+			return -1;
+		}
+	}
+	return kill(pid, sig);
+}

fuzz/fuzzer-client.c

@@ -0,0 +1,6 @@
+#include "fuzz.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	return fuzz_run_client(Data, Size, 0);
+}
+

fuzz/fuzzer-client_nomaths.c

@@ -0,0 +1,6 @@
+#include "fuzz.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	return fuzz_run_client(Data, Size, 1);
+}
+

fuzz/fuzzer-kexcurve25519.c

@@ -0,0 +1,69 @@
+#include "fuzz.h"
+#include "session.h"
+#include "fuzz-wrapfd.h"
+#include "debug.h"
+#include "runopts.h"
+#include "algo.h"
+#include "bignum.h"
+
+static struct key_context* keep_newkeys = NULL;
+/* An arbitrary limit */
+#define NUM_PARAMS 80
+static struct kex_curve25519_param *curve25519_params[NUM_PARAMS];
+
+static void setup() __attribute__((constructor));
+// Perform initial setup here to avoid hitting timeouts on first run
+static void setup() {
+	fuzz_common_setup();
+	fuzz_svr_setup();
+
+	keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
+	keep_newkeys->algo_kex = fuzz_get_algo(sshkex, "curve25519-sha256");
+	keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ED25519;
+	ses.newkeys = keep_newkeys;
+
+	/* Pre-generate parameters */
+	int i;
+	for (i = 0; i < NUM_PARAMS; i++) {
+		curve25519_params[i] = gen_kexcurve25519_param();
+	}
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+		return 0;
+	}
+
+	m_malloc_set_epoch(1);
+
+	if (setjmp(fuzz.jmp) == 0) {
+		/* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply() 
+		with DROPBEAR_KEX_CURVE25519 */
+		ses.newkeys = keep_newkeys;
+
+		/* Choose from the collection of curve25519 params */
+		unsigned int e = buf_getint(fuzz.input);
+		struct kex_curve25519_param *curve25519_param = curve25519_params[e % NUM_PARAMS];
+
+		buffer * ecdh_qs = buf_getstringbuf(fuzz.input);
+
+		ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS);
+		kexcurve25519_comb_key(curve25519_param, ecdh_qs, svr_opts.hostkey);
+
+		mp_clear(ses.dh_K);
+		m_free(ses.dh_K);
+		buf_free(ecdh_qs);
+
+		buf_free(ses.hash);
+		buf_free(ses.session_id);
+		/* kexhashbuf is freed in kexdh_comb_key */
+
+		m_malloc_free_epoch(1, 0);
+	} else {
+		m_malloc_free_epoch(1, 1);
+		TRACE(("dropbear_exit longjmped"))
+		/* dropbear_exit jumped here */
+	}
+
+	return 0;
+}

fuzz/fuzzer-kexdh.c

@@ -0,0 +1,72 @@
+#include "fuzz.h"
+#include "session.h"
+#include "fuzz-wrapfd.h"
+#include "debug.h"
+#include "runopts.h"
+#include "algo.h"
+#include "bignum.h"
+
+static struct key_context* keep_newkeys = NULL;
+#define NUM_PARAMS 80
+static struct kex_dh_param *dh_params[NUM_PARAMS];
+
+static void setup() __attribute__((constructor));
+// Perform initial setup here to avoid hitting timeouts on first run
+static void setup() {
+	fuzz_common_setup();
+	fuzz_svr_setup();
+
+	keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
+	keep_newkeys->algo_kex = fuzz_get_algo(sshkex, "diffie-hellman-group14-sha256");
+	keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
+	ses.newkeys = keep_newkeys;
+
+	/* Pre-generate parameters */
+	int i;
+	for (i = 0; i < NUM_PARAMS; i++) {
+		dh_params[i] = gen_kexdh_param();
+	}
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+		return 0;
+	}
+
+	m_malloc_set_epoch(1);
+
+	if (setjmp(fuzz.jmp) == 0) {
+		/* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply() 
+		with DROPBEAR_KEX_NORMAL_DH */
+		ses.newkeys = keep_newkeys;
+
+		/* Choose from the collection of ecdh params */
+		unsigned int e = buf_getint(fuzz.input);
+		struct kex_dh_param * dh_param = dh_params[e % NUM_PARAMS];
+
+		DEF_MP_INT(dh_e);
+		m_mp_init(&dh_e);
+		if (buf_getmpint(fuzz.input, &dh_e) != DROPBEAR_SUCCESS) {
+			dropbear_exit("Bad kex value");
+		}
+
+		ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS);
+		kexdh_comb_key(dh_param, &dh_e, svr_opts.hostkey);
+
+		mp_clear(ses.dh_K);
+		m_free(ses.dh_K);
+		mp_clear(&dh_e);
+
+		buf_free(ses.hash);
+		buf_free(ses.session_id);
+		/* kexhashbuf is freed in kexdh_comb_key */
+
+		m_malloc_free_epoch(1, 0);
+	} else {
+		m_malloc_free_epoch(1, 1);
+		TRACE(("dropbear_exit longjmped"))
+		/* dropbear_exit jumped here */
+	}
+
+	return 0;
+}

fuzz/fuzzer-kexecdh.c

@@ -0,0 +1,82 @@
+#include "fuzz.h"
+#include "session.h"
+#include "fuzz-wrapfd.h"
+#include "debug.h"
+#include "runopts.h"
+#include "algo.h"
+#include "bignum.h"
+
+static const struct dropbear_kex *ecdh[3]; /* 256, 384, 521 */
+static struct key_context* keep_newkeys = NULL;
+/* number of generated parameters. An arbitrary limit, but will delay startup */
+#define NUM_PARAMS 80
+static struct kex_ecdh_param *ecdh_params[NUM_PARAMS];
+
+static void setup() __attribute__((constructor));
+// Perform initial setup here to avoid hitting timeouts on first run
+static void setup() {
+	fuzz_common_setup();
+	fuzz_svr_setup();
+
+	/* ses gets zeroed by fuzz_set_input */
+	keep_newkeys = (struct key_context*)m_malloc(sizeof(struct key_context));
+	ecdh[0] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp256");
+	ecdh[1] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp384");
+	ecdh[2] = fuzz_get_algo(sshkex, "ecdh-sha2-nistp521");
+	assert(ecdh[0]);
+	assert(ecdh[1]);
+	assert(ecdh[2]);
+	keep_newkeys->algo_hostkey = DROPBEAR_SIGNKEY_ECDSA_NISTP256;
+	ses.newkeys = keep_newkeys;
+
+	/* Pre-generate parameters */
+	int i;
+	for (i = 0; i < NUM_PARAMS; i++) {
+		ses.newkeys->algo_kex = ecdh[i % 3];
+		ecdh_params[i] = gen_kexecdh_param();
+	}
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+
+	if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+		return 0;
+	}
+
+	m_malloc_set_epoch(1);
+
+	if (setjmp(fuzz.jmp) == 0) {
+		/* Based on recv_msg_kexdh_init()/send_msg_kexdh_reply() 
+		with DROPBEAR_KEX_ECDH */
+		ses.newkeys = keep_newkeys;
+
+		/* random choice of ecdh 256, 384, 521 */
+		unsigned char b = buf_getbyte(fuzz.input);
+		ses.newkeys->algo_kex = ecdh[b % 3];
+
+		/* Choose from the collection of ecdh params */
+		unsigned int e = buf_getint(fuzz.input);
+		struct kex_ecdh_param *ecdh_param = ecdh_params[e % NUM_PARAMS];
+
+		buffer * ecdh_qs = buf_getstringbuf(fuzz.input);
+
+		ses.kexhashbuf = buf_new(KEXHASHBUF_MAX_INTS);
+		kexecdh_comb_key(ecdh_param, ecdh_qs, svr_opts.hostkey);
+
+		mp_clear(ses.dh_K);
+		m_free(ses.dh_K);
+		buf_free(ecdh_qs);
+
+		buf_free(ses.hash);
+		buf_free(ses.session_id);
+		/* kexhashbuf is freed in kexdh_comb_key */
+
+		m_malloc_free_epoch(1, 0);
+	} else {
+		m_malloc_free_epoch(1, 1);
+		TRACE(("dropbear_exit longjmped"))
+		/* dropbear_exit jumped here */
+	}
+
+	return 0;
+}

fuzz/fuzzer-postauth_nomaths.c

@@ -0,0 +1,6 @@
+#include "fuzz.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	return fuzz_run_server(Data, Size, 1, 1);
+}
+

fuzz/fuzzer-preauth.c

@@ -0,0 +1,6 @@
+#include "fuzz.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	return fuzz_run_server(Data, Size, 0, 0);
+}
+

fuzz/fuzzer-preauth_nomaths.c

@@ -0,0 +1,6 @@
+#include "fuzz.h"
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	return fuzz_run_server(Data, Size, 1, 0);
+}
+

fuzz/fuzzer-pubkey.c

@@ -0,0 +1,54 @@
+#include "fuzz.h"
+#include "session.h"
+#include "fuzz-wrapfd.h"
+#include "debug.h"
+
+static void setup_fuzzer(void) {
+	fuzz_common_setup();
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	static int once = 0;
+	if (!once) {
+		setup_fuzzer();
+		once = 1;
+	}
+
+	if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+		return 0;
+	}
+
+	m_malloc_set_epoch(1);
+
+	if (setjmp(fuzz.jmp) == 0) {
+		buffer *line = buf_getstringbuf(fuzz.input);
+		buffer *keyblob = buf_getstringbuf(fuzz.input);
+
+		unsigned int algolen;
+		char* algoname = buf_getstring(keyblob, &algolen);
+
+		if (signature_type_from_name(algoname, algolen) == DROPBEAR_SIGNATURE_NONE) {
+			dropbear_exit("fuzzer imagined a bogus algorithm");
+		}
+
+		int ret = fuzz_checkpubkey_line(line, 5, "/home/me/authorized_keys",
+			algoname, algolen,
+			keyblob->data, keyblob->len);
+
+		if (ret == DROPBEAR_SUCCESS) {
+			/* fuzz_checkpubkey_line() should have cleaned up for failure */
+			svr_pubkey_options_cleanup();
+		}
+
+		buf_free(line);
+		buf_free(keyblob);
+		m_free(algoname);
+		m_malloc_free_epoch(1, 0);
+	} else {
+		m_malloc_free_epoch(1, 1);
+		TRACE(("dropbear_exit longjmped"))
+		/* dropbear_exit jumped here */
+	}
+
+	return 0;
+}

fuzz/fuzzer-verify.c

@@ -0,0 +1,79 @@
+#include "fuzz.h"
+#include "session.h"
+#include "fuzz-wrapfd.h"
+#include "debug.h"
+#include "dss.h"
+
+static void setup_fuzzer(void) {
+	fuzz_common_setup();
+}
+
+static buffer *verifydata;
+
+/* Tests reading a public key and verifying a signature */
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+	static int once = 0;
+	if (!once) {
+		setup_fuzzer();
+		verifydata = buf_new(30);
+		buf_putstring(verifydata, "x", 1);
+		once = 1;
+	}
+
+	if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
+		return 0;
+	}
+
+	m_malloc_set_epoch(1);
+
+	if (setjmp(fuzz.jmp) == 0) {
+		sign_key *key = new_sign_key();
+		enum signkey_type keytype = DROPBEAR_SIGNKEY_ANY;
+		if (buf_get_pub_key(fuzz.input, key, &keytype) == DROPBEAR_SUCCESS) {
+			enum signature_type sigtype;
+			if (keytype == DROPBEAR_SIGNKEY_RSA) {
+				/* Flip a coin to decide rsa signature type */
+				int flag = buf_getbyte(fuzz.input);
+				if (flag & 0x01) {
+					sigtype = DROPBEAR_SIGNATURE_RSA_SHA256;
+				} else {
+					sigtype = DROPBEAR_SIGNATURE_RSA_SHA1;
+				}
+			} else {
+				sigtype = signature_type_from_signkey(keytype);
+			}
+			if (buf_verify(fuzz.input, key, sigtype, verifydata) == DROPBEAR_SUCCESS) {
+				/* The fuzzer is capable of generating keys with a signature to match.
+				We don't want false positives if the key is bogus, since a client/server 
+				wouldn't be trusting a bogus key anyway */
+				int boguskey = 0;
+
+				if (keytype == DROPBEAR_SIGNKEY_DSS) {
+					/* So far have seen dss keys with bad p/q/g domain parameters */
+					int pprime, qprime, trials;
+					trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->p));
+					assert(mp_prime_is_prime(key->dsskey->p, trials, &pprime) == MP_OKAY);
+					trials = mp_prime_rabin_miller_trials(mp_count_bits(key->dsskey->q));
+					assert(mp_prime_is_prime(key->dsskey->q, trials, &qprime) == MP_OKAY);
+					boguskey = !(pprime && qprime);
+					/* Could also check g**q mod p == 1 */
+				}
+
+				if (!boguskey) {
+					printf("Random key/signature managed to verify!\n");
+					abort();
+				}
+
+
+			}
+		}
+		sign_key_free(key);
+		m_malloc_free_epoch(1, 0);
+	} else {
+		m_malloc_free_epoch(1, 1);
+		TRACE(("dropbear_exit longjmped"))
+		/* dropbear_exit jumped here */
+	}
+
+	return 0;
+}

fuzzers_test.sh

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# runs fuzz corpus with standalone fuzzers
+
+result=0
+
+test -d fuzzcorpus && hg --repository fuzzcorpus/ pull || hg clone https://hg.ucc.asn.au/dropbear-fuzzcorpus fuzzcorpus || exit 1
+for f in `make list-fuzz-targets`; do
+    # use xargs to split the too-long argument list
+    # -q quiet because travis has a logfile limit
+    echo fuzzcorpus/$f/* | xargs -n 1000 ./$f -q || result=1
+done
+
+exit $result

gcm.c

@@ -0,0 +1,120 @@
+/*
+ * Dropbear SSH
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * Copyright (c) 2020 by Vladislav Grishenko
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "algo.h"
+#include "dbutil.h"
+#include "gcm.h"
+
+#if DROPBEAR_ENABLE_GCM_MODE
+
+#define GHASH_LEN 16
+
+static const struct dropbear_hash dropbear_ghash =
+	{NULL, 0, GHASH_LEN};
+
+static int dropbear_gcm_start(int cipher, const unsigned char *IV,
+			const unsigned char *key, int keylen,
+			int UNUSED(num_rounds), dropbear_gcm_state *state) {
+	int err;
+
+	TRACE2(("enter dropbear_gcm_start"))
+
+	if ((err = gcm_init(&state->gcm, cipher, key, keylen)) != CRYPT_OK) {
+		return err;
+	}
+	memcpy(state->iv, IV, GCM_NONCE_LEN);
+
+	TRACE2(("leave dropbear_gcm_start"))
+	return CRYPT_OK;
+}
+
+static int dropbear_gcm_crypt(unsigned int UNUSED(seq),
+			const unsigned char *in, unsigned char *out,
+			unsigned long len, unsigned long taglen,
+			dropbear_gcm_state *state, int direction) {
+	unsigned char *iv, tag[GHASH_LEN];
+	int i, err;
+
+	TRACE2(("enter dropbear_gcm_crypt"))
+
+	if (len < 4 || taglen != GHASH_LEN) {
+		return CRYPT_ERROR;
+	}
+
+	gcm_reset(&state->gcm);
+
+	if ((err = gcm_add_iv(&state->gcm,
+				state->iv, GCM_NONCE_LEN)) != CRYPT_OK) {
+		return err;
+	}
+
+	if ((err = gcm_add_aad(&state->gcm, in, 4)) != CRYPT_OK) {
+		return err;
+	}
+
+	if ((err = gcm_process(&state->gcm, (unsigned char *) in + 4,
+				len - 4, out + 4, direction)) != CRYPT_OK) {
+		return err;
+	}
+
+	if (direction == LTC_ENCRYPT) {
+		gcm_done(&state->gcm, out + len, &taglen);
+	} else {
+		gcm_done(&state->gcm, tag, &taglen);
+		if (constant_time_memcmp(in + len, tag, taglen) != 0) {
+			return CRYPT_ERROR;
+		}
+	}
+
+	/* increment invocation counter */
+	iv = state->iv + GCM_IVFIX_LEN;
+	for (i = GCM_IVCTR_LEN - 1; i >= 0 && ++iv[i] == 0; i--);
+
+	TRACE2(("leave dropbear_gcm_crypt"))
+	return CRYPT_OK;
+}
+
+static int dropbear_gcm_getlength(unsigned int UNUSED(seq),
+			const unsigned char *in, unsigned int *outlen,
+			unsigned long len, dropbear_gcm_state* UNUSED(state)) {
+	TRACE2(("enter dropbear_gcm_getlength"))
+
+	if (len < 4) {
+		return CRYPT_ERROR;
+	}
+
+	LOAD32H(*outlen, in);
+
+	TRACE2(("leave dropbear_gcm_getlength"))
+	return CRYPT_OK;
+}
+
+const struct dropbear_cipher_mode dropbear_mode_gcm =
+	{(void *)dropbear_gcm_start, NULL, NULL,
+	 (void *)dropbear_gcm_crypt,
+	 (void *)dropbear_gcm_getlength, &dropbear_ghash};
+
+#endif /* DROPBEAR_ENABLE_GCM_MODE */

gcm.h

@@ -0,0 +1,47 @@
+/*
+ * Dropbear SSH
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * Copyright (c) 2020 by Vladislav Grishenko
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#ifndef DROPBEAR_DROPBEAR_GCM_H_
+#define DROPBEAR_DROPBEAR_GCM_H_
+
+#include "includes.h"
+#include "algo.h"
+
+#if DROPBEAR_ENABLE_GCM_MODE
+
+#define GCM_IVFIX_LEN 4
+#define GCM_IVCTR_LEN 8
+#define GCM_NONCE_LEN (GCM_IVFIX_LEN + GCM_IVCTR_LEN)
+
+typedef struct {
+	gcm_state gcm;
+	unsigned char iv[GCM_NONCE_LEN];
+} dropbear_gcm_state;
+
+extern const struct dropbear_cipher_mode dropbear_mode_gcm;
+
+#endif /* DROPBEAR_ENABLE_GCM_MODE */
+
+#endif /* DROPBEAR_DROPBEAR_GCM_H_ */

gendss.c

@@ -68,6 +68,7 @@ dropbear_dss_key * gen_dss_priv_key(unsigned int size) {
 static void getq(const dropbear_dss_key *key) {
 
 	unsigned char buf[QSIZE];
+	int trials;
 
 	/* 160 bit prime */
 	genrandom(buf, QSIZE);
@@ -76,8 +77,9 @@ static void getq(const dropbear_dss_key *key) {
 
 	bytes_to_mp(key->q, buf, QSIZE);
 
-	/* 18 rounds are required according to HAC */
-	if (mp_prime_next_prime(key->q, 18, 0) != MP_OKAY) {
+	/* ask FIPS 186.4 how many Rabin-Miller trials are required */
+	trials = mp_prime_rabin_miller_trials(mp_count_bits(key->q));
+	if (mp_prime_next_prime(key->q, trials, 0) != MP_OKAY) {
 		fprintf(stderr, "DSS key generation failed\n");
 		exit(1);
 	}
@@ -89,7 +91,7 @@ static void getp(const dropbear_dss_key *key, unsigned int size) {
 	DEF_MP_INT(tempC);
 	DEF_MP_INT(tempP);
 	DEF_MP_INT(temp2q);
-	int result;
+	int result, trials;
 	unsigned char *buf;
 
 	m_mp_init_multi(&tempX, &tempC, &tempP, &temp2q, NULL);
@@ -129,9 +131,10 @@ static void getp(const dropbear_dss_key *key, unsigned int size) {
 			exit(1);
 		}
 
-		/* now check for prime, 5 rounds is enough according to HAC */
+		/* ask FIPS 186.4 how many Rabin-Miller trials are required */
+		trials = mp_prime_rabin_miller_trials(mp_count_bits(key->p));
 		/* result == 1  =>  p is prime */
-		if (mp_prime_is_prime(key->p, 5, &result) != MP_OKAY) {
+		if (mp_prime_is_prime(key->p, trials, &result) != MP_OKAY) {
 			fprintf(stderr, "DSS key generation failed\n");
 			exit(1);
 		}

gened25519.c

@@ -0,0 +1,47 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#include "includes.h"
+#include "dbutil.h"
+#include "dbrandom.h"
+#include "curve25519.h"
+#include "gened25519.h"
+
+#if DROPBEAR_ED25519
+
+dropbear_ed25519_key * gen_ed25519_priv_key(unsigned int size) {
+
+	dropbear_ed25519_key *key;
+
+	if (size != 256) {
+		dropbear_exit("Ed25519 keys have a fixed size of 256 bits");
+	}
+
+	key = m_malloc(sizeof(*key));
+	dropbear_ed25519_make_key(key->pub, key->priv);
+
+	return key;
+}
+
+#endif /* DROPBEAR_ED25519 */

gened25519.h

@@ -0,0 +1,36 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+
+#ifndef DROPBEAR_GENED25519_H_
+#define DROPBEAR_GENED25519_H_
+
+#include "ed25519.h"
+
+#if DROPBEAR_ED25519
+
+dropbear_ed25519_key * gen_ed25519_priv_key(unsigned int size);
+
+#endif /* DROPBEAR_ED25519 */
+
+#endif /* DROPBEAR_GENED25519_H_ */

genrsa.c

@@ -53,10 +53,7 @@ dropbear_rsa_key * gen_rsa_priv_key(unsigned int size) {
 	m_mp_alloc_init_multi(&key->e, &key->n, &key->d, &key->p, &key->q, NULL);
 	m_mp_init_multi(&pminus, &lcm, &qminus, NULL);
 
-	if (mp_set_int(key->e, RSA_E) != MP_OKAY) {
-		fprintf(stderr, "RSA generation failed\n");
-		exit(1);
-	}
+	mp_set_ul(key->e, RSA_E);
 
 	while (1) {
 		getrsaprime(key->p, &pminus, key->e, size/16);
@@ -95,6 +92,7 @@ static void getrsaprime(mp_int* prime, mp_int *primeminus,
 		mp_int* rsa_e, unsigned int size_bytes) {
 
 	unsigned char *buf;
+	int trials;
 	DEF_MP_INT(temp_gcd);
 
 	buf = (unsigned char*)m_malloc(size_bytes);
@@ -108,8 +106,9 @@ static void getrsaprime(mp_int* prime, mp_int *primeminus,
 
 		bytes_to_mp(prime, buf, size_bytes);
 
-		/* find the next integer which is prime, 8 round of miller-rabin */
-		if (mp_prime_next_prime(prime, 8, 0) != MP_OKAY) {
+		/* find the next integer which is prime */
+		trials = mp_prime_rabin_miller_trials(mp_count_bits(prime));
+		if (mp_prime_next_prime(prime, trials, 0) != MP_OKAY) {
 			fprintf(stderr, "RSA generation failed\n");
 			exit(1);
 		}

gensignkey.c

@@ -4,18 +4,26 @@
 #include "ecdsa.h"
 #include "genrsa.h"
 #include "gendss.h"
+#include "gened25519.h"
 #include "signkey.h"
 #include "dbrandom.h"
 
 /* Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
-static int buf_writefile(buffer * buf, const char * filename) {
+static int buf_writefile(buffer * buf, const char * filename, int skip_exist) {
 	int ret = DROPBEAR_FAILURE;
 	int fd = -1;
 
 	fd = open(filename, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
 	if (fd < 0) {
-		dropbear_log(LOG_ERR, "Couldn't create new file %s: %s",
-			filename, strerror(errno));
+		/* If generating keys on connection (skip_exist) it's OK to get EEXIST
+		- we probably just lost a race with another connection to generate the key */
+		if (skip_exist && errno == EEXIST) {
+			ret = DROPBEAR_SUCCESS;
+		} else {
+			dropbear_log(LOG_ERR, "Couldn't create new file %s: %s",
+				filename, strerror(errno));
+		}
+
 		goto out;
 	}
 
@@ -68,6 +76,10 @@ static int get_default_bits(enum signkey_type keytype)
 			return 384;
 		case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
 			return 256;
+#endif
+#if DROPBEAR_ED25519
+		case DROPBEAR_SIGNKEY_ED25519:
+			return 256;
 #endif
 		default:
 			return 0;
@@ -118,6 +130,11 @@ int signkey_generate(enum signkey_type keytype, int bits, const char* filename,
 				*signkey_key_ptr(key, keytype) = ecckey;
 			}
 			break;
+#endif
+#if DROPBEAR_ED25519
+		case DROPBEAR_SIGNKEY_ED25519:
+			key->ed25519key = gen_ed25519_priv_key(bits);
+			break;
 #endif
 		default:
 			dropbear_exit("Internal error");
@@ -134,7 +151,7 @@ int signkey_generate(enum signkey_type keytype, int bits, const char* filename,
 
 	fn_temp = m_malloc(strlen(filename) + 30);
 	snprintf(fn_temp, strlen(filename)+30, "%s.tmp%d", filename, getpid());
-	ret = buf_writefile(buf, fn_temp);
+	ret = buf_writefile(buf, fn_temp, 0);
 
 	if (ret == DROPBEAR_FAILURE) {
 		goto out;
@@ -144,14 +161,24 @@ int signkey_generate(enum signkey_type keytype, int bits, const char* filename,
 		/* If generating keys on connection (skipexist) it's OK to get EEXIST 
 		- we probably just lost a race with another connection to generate the key */
 		if (!(skip_exist && errno == EEXIST)) {
-			dropbear_log(LOG_ERR, "Failed moving key file to %s: %s", filename,
-				strerror(errno));
-			/* XXX fallback to non-atomic copy for some filesystems? */
-			ret = DROPBEAR_FAILURE;
+			if (errno == EPERM || errno == EACCES) {
+				/* Non-atomic fallback when hard-links not allowed or unsupported */
+				buf_setpos(buf, 0);
+				ret = buf_writefile(buf, filename, skip_exist);
+			} else {
+				dropbear_log(LOG_ERR, "Failed moving key file to %s: %s", filename,
+					strerror(errno));
+				ret = DROPBEAR_FAILURE;
+			}
+
 			goto out;
 		}
 	}
 
+	/* ensure directory update is flushed to disk, otherwise we can end up
+	with zero-byte hostkey files if the power goes off */
+	fsync_parent_dir(filename);
+
 out:
 	if (buf) {
 		buf_burn(buf);

ifndef_wrapper.sh

@@ -2,6 +2,6 @@
 
 # Wrap all "#define X Y" with a #ifndef X...#endif"
 
-sed -E 's/^( *#define ([^ ]+) .*)/#ifndef \2\
+sed 's/^\( *#define \([^ ][^ ]*\) .*\)/#ifndef \2\
 \1\
 #endif/' 

includes.h

@@ -25,7 +25,6 @@
 #ifndef DROPBEAR_INCLUDES_H_
 #define DROPBEAR_INCLUDES_H_
 
-
 #include "options.h"
 #include "debug.h"
 
@@ -56,6 +55,7 @@
 #include <stdarg.h>
 #include <dirent.h>
 #include <time.h>
+#include <setjmp.h>
 
 #ifdef HAVE_UTMP_H
 #include <utmp.h>
@@ -123,6 +123,10 @@
 #include <sys/uio.h>
 #endif
 
+#ifdef HAVE_SYS_RANDOM_H
+#include <sys/random.h>
+#endif
+
 #ifdef BUNDLED_LIBTOM
 #include "libtomcrypt/src/headers/tomcrypt.h"
 #include "libtommath/tommath.h"
@@ -131,7 +135,6 @@
 #include <tommath.h>
 #endif
 
-
 #include "compat.h"
 
 #ifndef HAVE_U_INT8_T
@@ -155,13 +158,23 @@ typedef unsigned int u_int32_t;
 typedef u_int32_t uint32_t;
 #endif /* HAVE_UINT32_T */
 
+#ifndef SIZE_T_MAX
+#define SIZE_T_MAX ULONG_MAX
+#endif /* SIZE_T_MAX */
+
 #ifdef HAVE_LINUX_PKT_SCHED_H
 #include <linux/types.h>
 #include <linux/pkt_sched.h>
 #endif
 
+#if DROPBEAR_PLUGIN
+#include <dlfcn.h>
+#endif
+
 #include "fake-rfc2553.h"
 
+#include "fuzz.h"
+
 #ifndef LOG_AUTHPRIV
 #define LOG_AUTHPRIV LOG_AUTH
 #endif