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

@@ -21,7 +21,8 @@
 /scp-progress
 Makefile
 config.h
-config.h.in
-configure
 default_options_guard.h
 tags
+.pytest*
+*.pyc
+/test/venv

.hgignore

@@ -1,2 +1,6 @@
-.*\.o
+\..*\.swp
 .*~
+tags
+.pytest*
+.*\.pyc
+test/venv

.hgsigs

@@ -28,3 +28,4 @@ fd1981f41c626a969f07b4823848deaefef3c8aa 0 iQIcBAABCgAGBQJW4W2TAAoJEESTFJTynGdzu
 ebcdb893992d286d363e60f5353d6e1401e7084b 0 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
 4877afd51e041eca7749cc46b57fd80aa23815b4 0 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
 88f63b8b0f131f24aa90c9b852622b922b1ad738 0 iQIzBAABCgAdFiEE9zR+8u4uB6JnYoypRJMUlPKcZ3MFAl71/sAACgkQRJMUlPKcZ3OlSQ/9GYLotOmsYK0gvSfWLYR9a8WGgT/4EU6RgAkMBLS9TBp0E3V4VUDralnqoId7hNO2cUkRS7boOM2g4/YRShah8gonSJa70lKjUpDeQUPuGwUYWLNKr9qxJtnAcd1rOE4WYxKEUfjPWHBbVsT3QIIdj1Zy31GDKZgELRBQeOyt62RdXYHMaMHHDgg2U/wO9bcRRe5G7mYJf7Vm8sAWyTZXvta2jORxgs4XxWe7xJ9Dj0lMSG5HmfvH5NrGHM1GK3pL0GREKj2+xNSFdkSeHIgSSoHM2qZTVSWtNfx0+fZaRBgvXPPYzDTTghj1mKEaPFoRzg/B8s+NmHupJftT1yyapKFjALo1N6eaPHRRSwVfmnoWSJLu4fwL8TK5wMJr9eGl3QgAnperQPEFT9UHJBIwZ1D+RMuI3pEESdHBJFAYIAyisJI6XyzMhLsysoShlHs6OjFcJ9jTe4pzg9pO+KaPbLYsBJxJUsrtHwV8P9CHxY6CEuKm0AZjYDopYhzLuAUjGJjYDf/C9vJ/xtTOqIm9nywfcFwqgLrmQFhNHHGyOJVr+y/cey1sT9E4/gBv9kor+6qSITALv2g0JTaOpzpkE0zbafUy2r777Wex4WNQEha6bYZFi2aiqxqqX93UHzv+YhmN8n9mlc21xoZMPNtAb2mSxx7rO+PScb5uflKOCYE=
+5879c5829e8569466386e7c64252b01b99705628 0 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

.hgtags

@@ -60,3 +60,4 @@ c31276613181c5cff7854e7ef586ace03424e55e DROPBEAR_2017.75
 009d52ae26d35f3381c801e02318fa9be34be93c DROPBEAR_2019.78
 e2e4929d057b09422f2ea4556fb64209aff58161 DROPBEAR_2020.79
 73646de50f1351735c868d4874f058ff9ad62c96 DROPBEAR_2020.80
+4b984c42372d01fcc2fd487c58af6a5aa65eb88e DROPBEAR_2020.81

.travis.yml

@@ -1,78 +0,0 @@
-language: c
-
-git:
-  depth: 3
-
-# use focal which provides libtommath 1.20
-dist: focal
-
-matrix:
-  include:
-    - name: "plain linux"
-      compiler: gcc
-      env: WEXTRAFLAGS=-Werror
-    - name: "multi binary"
-      env: MULTI=1 WEXTRAFLAGS=-Werror
-    - name: "bundled libtom, xenial, no writev()"
-      # NOWRITEV is unrelated to libtom/xenial, test here to save a job
-      env: CONFIGURE_FLAGS=--enable-bundled-libtom WEXTRAFLAGS=-Werror NOWRITEV=1 
-      # can use an older distro with bundled libtom
-      dist: xenial
-    - name: "linux clang"
-      os: linux
-      compiler: clang
-      env: WEXTRAFLAGS=-Werror
-    - name: "osx"
-      os: osx
-      compiler: clang
-      # OS X says daemon() and utmp are deprecated
-      env: WEXTRAFLAGS="-Wno-deprecated-declarations -Werror"
-    # Note: the fuzzing malloc wrapper doesn't replace free() in system libtomcrypt, so need bundled.
-    # Address sanitizer
-    - name: "fuzz-asan"
-      env: DO_FUZZ=1 CONFIGURE_FLAGS="--enable-fuzz --disable-harden --enable-bundled-libtom" WEXTRAFLAGS=-Werror LDFLAGS=-fsanitize=address EXTRACFLAGS=-fsanitize=address CXX=clang++
-      compiler: clang
-    # Undefined Behaviour sanitizer
-    - name: "fuzz-ubsan"
-      # don't fail with alignment due to https://github.com/libtom/libtomcrypt/issues/549
-      env: DO_FUZZ=1 CONFIGURE_FLAGS="--enable-fuzz --disable-harden --enable-bundled-libtom" WEXTRAFLAGS=-Werror LDFLAGS=-fsanitize=undefined EXTRACFLAGS="-fsanitize=undefined -fno-sanitize-recover=undefined -fsanitize-recover=alignment" CXX=clang++
-      compiler: clang
-
-# container-based builds
-addons:
-  apt:
-    packages:
-    # packages list: https://github.com/travis-ci/apt-package-whitelist/blob/master/ubuntu-precise
-    - zlib1g-dev
-    - libtomcrypt-dev
-    - libtommath-dev
-    - mercurial
-
-before_install:
-  - if [ "$CC" = "clang" ]; then WEXTRAFLAGS="$WEXTRAFLAGS -Wno-error=incompatible-library-redeclaration" ; fi  # workaround
-
-install:
-  - autoconf 
-  - autoheader 
-  - ./configure $CONFIGURE_FLAGS CFLAGS="-O2 -Wall -Wno-pointer-sign $WEXTRAFLAGS $EXTRACFLAGS" --prefix="$HOME/inst" || (cat config.log; exit 1)
-  - if [ "$NOWRITEV" = "1" ]; then sed -i -e s/HAVE_WRITEV/DONT_HAVE_WRITEV/ config.h ; fi
-  - make lint
-  - make -j3 
-  - test -z $DO_FUZZ || make fuzzstandalone
-  # avoid concurrent install, osx/freebsd is racey (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=208093)
-  - make install 
-
-script:
-  - ~/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
-  - ~/inst/bin/dropbearkey -t ed25519 -f tested25519
-  - test -z $DO_FUZZ || ./fuzzers_test.sh
-
-branches:
-  only:
-    - master
-    - coverity
-

INSTALL

@@ -6,12 +6,12 @@ Basic Dropbear build instructions:
   localoptions.h should be located in the build directory if you are
   building out of tree.
 
-- If using a Mercurial or Git checkout, "autoconf; autoheader"
-
 - 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"

Makefile.in

@@ -35,8 +35,8 @@ 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 \
-		curve25519.o ed25519.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
 
@@ -62,7 +62,7 @@ CONVERTOBJS=dropbearconvert.o keyimport.o
 SCPOBJS=scp.o progressmeter.o atomicio.o scpmisc.o compat.o
 
 ifeq (@DROPBEAR_FUZZ@, 1)
-	allobjs = $(COMMONOBJS) fuzz-common.o  fuzz-wrapfd.o $(CLISVROBJS) $(CLIOBJS) $(SVROBJS) @CRYPTLIB@
+	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))
 
@@ -72,6 +72,7 @@ ifeq (@DROPBEAR_FUZZ@, 1)
 	dropbearconvertobjs=$(allobjs) $(CONVERTOBJS)
 	# CXX only set when fuzzing
 	CXX=@CXX@
+	FUZZ_CLEAN=fuzz-clean
 else
 	dropbearobjs=$(COMMONOBJS) $(CLISVROBJS) $(SVROBJS)
 	dbclientobjs=$(COMMONOBJS) $(CLISVROBJS) $(CLIOBJS)
@@ -235,7 +236,7 @@ $(STATIC_LTC): $(OPTION_HEADERS)
 $(STATIC_LTM): $(OPTION_HEADERS)
 	$(MAKE) -C libtommath
 
-.PHONY : clean sizes thisclean distclean tidy ltc-clean ltm-clean lint
+.PHONY : clean sizes thisclean distclean tidy ltc-clean ltm-clean lint check
 
 ltc-clean:
 	$(MAKE) -C libtomcrypt clean
@@ -246,7 +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) \
@@ -264,54 +265,46 @@ tidy:
 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-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-harness.o
-fuzzstandalone: fuzz-harness.o fuzz-targets
+fuzzstandalone: FUZZLIB=fuzz/fuzz-harness.o
+fuzzstandalone: fuzz/fuzz-harness.o fuzz-targets
 
-fuzz-harness.o: $(HEADERS) $(LIBTOM_DEPS) Makefile $(allobjs) fuzz-common.o
-
-# build all the fuzzers. This will require fail to link unless built with
-# make fuzz-targets FUZZLIB=-lFuzzer.a 
-# or similar - the library provides main().
+# 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)
 
-fuzzer-preauth: fuzzer-preauth.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
+$(FUZZ_TARGETS): $(FUZZ_OBJS) $(allobjs) $(LIBTOM_DEPS) 
+	$(CXX) $(CXXFLAGS) fuzz/$@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
 
-fuzzer-preauth_nomaths: fuzzer-preauth_nomaths.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.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
 
-fuzzer-pubkey: fuzzer-pubkey.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-verify: fuzzer-verify.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-kexdh: fuzzer-kexdh.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-kexecdh: fuzzer-kexecdh.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-kexcurve25519: fuzzer-kexcurve25519.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-client: fuzzer-client.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
-
-fuzzer-client_nomaths: fuzzer-client_nomaths.o fuzz-harness.o
-	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(allobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
+# Skip custom mutators for -fsanitize-memory since libfuzzer doesn't initialise memory
+# Pending fix for it https://github.com/google/oss-fuzz/issues/4605
+ifeq (,$(findstring fsanitize=memory, $(CFLAGS)))
+$(MUTATOR_FUZZERS): allobjs += fuzz/fuzz-sshpacketmutator.o
+endif
 
 fuzzer-%.options: Makefile
 	echo "[libfuzzer]"               > $@
@@ -329,3 +322,6 @@ fuzz-hostkeys:
 	/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)

auth.h

@@ -30,7 +30,6 @@
 #include "chansession.h"
 
 void svr_authinitialise(void);
-void cli_authinitialise(void);
 
 /* Server functions */
 void recv_msg_userauth_request(void);

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
@@ -68,6 +71,9 @@ struct Channel {
 	/* whether close/eof messages have been exchanged */
 	int sent_close, recv_close;
 	int recv_eof, sent_eof;
+	/* 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
@@ -77,8 +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);
 
@@ -89,13 +93,12 @@ 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*);
-	/* Called to check whether a channel should close, separately from the FD being closed.
+	/* Called to check whether a channel should close, separately from the FD being EOF.
 	Used for noticing process exiting */
-	int (*check_close)(const struct Channel*);
+	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 */
@@ -104,7 +107,7 @@ struct ChanType {
 	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[]);

cli-agentfwd.c

@@ -47,7 +47,6 @@
 static int new_agent_chan(struct Channel * channel);
 
 const struct ChanType cli_chan_agent = {
-	0, /* sepfds */
 	"auth-agent@openssh.com",
 	new_agent_chan,
 	NULL,
@@ -94,6 +93,7 @@ static int new_agent_chan(struct Channel * channel) {
 
 	channel->readfd = fd;
 	channel->writefd = fd;
+	channel->bidir_fd = 1;
 
 	return 0;
 }

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

@@ -125,7 +125,7 @@ void recv_msg_userauth_pk_ok() {
 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
+	/* TODO: rsa-sha256 agent */
 	if (key->source == SIGNKEY_SOURCE_AGENT) {
 		/* Format the agent signature ourselves, as buf_put_sign would. */
 		buffer *sigblob;
@@ -176,6 +176,7 @@ static void send_msg_userauth_pubkey(sign_key *key, enum signature_type sigtype,
 		buf_putbytes(sigbuf, ses.writepayload->data, ses.writepayload->len);
 		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();

cli-chansession.c

@@ -46,7 +46,6 @@ 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 */
@@ -344,6 +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;
 }
 
@@ -383,7 +383,6 @@ 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,

cli-main.c

@@ -47,6 +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;
@@ -71,7 +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);

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;
@@ -450,12 +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;
@@ -889,6 +887,7 @@ static void add_extendedopt(const char* origstr) {
 #if DROPBEAR_CLI_ANYTCPFWD
 			"\tExitOnForwardFailure\n"
 #endif
+			"\tDisableTrivialAuth\n"
 #ifndef DISABLE_SYSLOG
 			"\tUseSyslog\n"
 #endif
@@ -916,5 +915,10 @@ static void add_extendedopt(const char* origstr) {
 		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

@@ -165,6 +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;
@@ -245,6 +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"))
@@ -408,9 +412,17 @@ 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) {

cli-tcpfwd.c

@@ -35,7 +35,6 @@
 static int newtcpforwarded(struct Channel * channel);
 
 const struct ChanType cli_chan_tcpremote = {
-	1, /* sepfds */
 	"forwarded-tcpip",
 	newtcpforwarded,
 	NULL,
@@ -51,7 +50,6 @@ 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,
@@ -273,12 +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

@@ -239,6 +239,9 @@ algo_type ssh_nocompress[] = {
 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
@@ -250,6 +253,9 @@ algo_type sigalgs[] = {
 #if DROPBEAR_ECC_521
 	{"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
 #if DROPBEAR_RSA_SHA256

common-channel.c

@@ -154,7 +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;
@@ -284,24 +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->sent_close
-		&& 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	
+	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."))
@@ -317,22 +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 
@@ -356,8 +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"))
@@ -365,6 +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);
@@ -373,9 +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))
 	}
 }
 
@@ -780,14 +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"))
 }
 
@@ -1073,7 +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) {
@@ -1103,7 +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);
@@ -1136,6 +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;
 
@@ -1152,7 +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-runopts.c

@@ -101,4 +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;
+	}
+
+}
 

config.guess

@@ -1,8 +1,8 @@
 #! /bin/sh
 # Attempt to guess a canonical system name.
-#   Copyright 1992-2019 Free Software Foundation, Inc.
+#   Copyright 1992-2021 Free Software Foundation, Inc.
 
-timestamp='2019-03-04'
+timestamp='2021-01-25'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -27,12 +27,12 @@ timestamp='2019-03-04'
 # Originally written by Per Bothner; maintained since 2000 by Ben Elliston.
 #
 # You can get the latest version of this script from:
-# https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+# https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
 #
 # Please send patches to <config-patches@gnu.org>.
 
 
-me=`echo "$0" | sed -e 's,.*/,,'`
+me=$(echo "$0" | sed -e 's,.*/,,')
 
 usage="\
 Usage: $0 [OPTION]
@@ -50,7 +50,7 @@ version="\
 GNU config.guess ($timestamp)
 
 Originally written by Per Bothner.
-Copyright 1992-2019 Free Software Foundation, Inc.
+Copyright 1992-2021 Free Software Foundation, Inc.
 
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE."
@@ -99,9 +99,11 @@ tmp=
 trap 'test -z "$tmp" || rm -fr "$tmp"' 0 1 2 13 15
 
 set_cc_for_build() {
+    # prevent multiple calls if $tmp is already set
+    test "$tmp" && return 0
     : "${TMPDIR=/tmp}"
     # shellcheck disable=SC2039
-    { tmp=`(umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null` && test -n "$tmp" && test -d "$tmp" ; } ||
+    { tmp=$( (umask 077 && mktemp -d "$TMPDIR/cgXXXXXX") 2>/dev/null) && test -n "$tmp" && test -d "$tmp" ; } ||
 	{ test -n "$RANDOM" && tmp=$TMPDIR/cg$$-$RANDOM && (umask 077 && mkdir "$tmp" 2>/dev/null) ; } ||
 	{ tmp=$TMPDIR/cg-$$ && (umask 077 && mkdir "$tmp" 2>/dev/null) && echo "Warning: creating insecure temp directory" >&2 ; } ||
 	{ echo "$me: cannot create a temporary directory in $TMPDIR" >&2 ; exit 1 ; }
@@ -129,16 +131,14 @@ if test -f /.attbin/uname ; then
 	PATH=$PATH:/.attbin ; export PATH
 fi
 
-UNAME_MACHINE=`(uname -m) 2>/dev/null` || UNAME_MACHINE=unknown
-UNAME_RELEASE=`(uname -r) 2>/dev/null` || UNAME_RELEASE=unknown
-UNAME_SYSTEM=`(uname -s) 2>/dev/null`  || UNAME_SYSTEM=unknown
-UNAME_VERSION=`(uname -v) 2>/dev/null` || UNAME_VERSION=unknown
+UNAME_MACHINE=$( (uname -m) 2>/dev/null) || UNAME_MACHINE=unknown
+UNAME_RELEASE=$( (uname -r) 2>/dev/null) || UNAME_RELEASE=unknown
+UNAME_SYSTEM=$( (uname -s) 2>/dev/null) || UNAME_SYSTEM=unknown
+UNAME_VERSION=$( (uname -v) 2>/dev/null) || UNAME_VERSION=unknown
 
 case "$UNAME_SYSTEM" in
 Linux|GNU|GNU/*)
-	# If the system lacks a compiler, then just pick glibc.
-	# We could probably try harder.
-	LIBC=gnu
+	LIBC=unknown
 
 	set_cc_for_build
 	cat <<-EOF > "$dummy.c"
@@ -147,17 +147,29 @@ Linux|GNU|GNU/*)
 	LIBC=uclibc
 	#elif defined(__dietlibc__)
 	LIBC=dietlibc
-	#else
+	#elif defined(__GLIBC__)
 	LIBC=gnu
+	#else
+	#include <stdarg.h>
+	/* First heuristic to detect musl libc.  */
+	#ifdef __DEFINED_va_list
+	LIBC=musl
+	#endif
 	#endif
 	EOF
-	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g'`"
+	eval "$($CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^LIBC' | sed 's, ,,g')"
 
-	# If ldd exists, use it to detect musl libc.
-	if command -v ldd >/dev/null && \
-		ldd --version 2>&1 | grep -q ^musl
-	then
-	    LIBC=musl
+	# Second heuristic to detect musl libc.
+	if [ "$LIBC" = unknown ] &&
+	   command -v ldd >/dev/null &&
+	   ldd --version 2>&1 | grep -q ^musl; then
+		LIBC=musl
+	fi
+
+	# If the system lacks a compiler, then just pick glibc.
+	# We could probably try harder.
+	if [ "$LIBC" = unknown ]; then
+		LIBC=gnu
 	fi
 	;;
 esac
@@ -176,20 +188,20 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	#
 	# Note: NetBSD doesn't particularly care about the vendor
 	# portion of the name.  We always set it to "unknown".
-	sysctl="sysctl -n hw.machine_arch"
-	UNAME_MACHINE_ARCH=`(uname -p 2>/dev/null || \
-	    "/sbin/$sysctl" 2>/dev/null || \
-	    "/usr/sbin/$sysctl" 2>/dev/null || \
-	    echo unknown)`
+	UNAME_MACHINE_ARCH=$( (uname -p 2>/dev/null || \
+	    /sbin/sysctl -n hw.machine_arch 2>/dev/null || \
+	    /usr/sbin/sysctl -n hw.machine_arch 2>/dev/null || \
+	    echo unknown))
 	case "$UNAME_MACHINE_ARCH" in
+	    aarch64eb) machine=aarch64_be-unknown ;;
 	    armeb) machine=armeb-unknown ;;
 	    arm*) machine=arm-unknown ;;
 	    sh3el) machine=shl-unknown ;;
 	    sh3eb) machine=sh-unknown ;;
 	    sh5el) machine=sh5le-unknown ;;
 	    earmv*)
-		arch=`echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,'`
-		endian=`echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p'`
+		arch=$(echo "$UNAME_MACHINE_ARCH" | sed -e 's,^e\(armv[0-9]\).*$,\1,')
+		endian=$(echo "$UNAME_MACHINE_ARCH" | sed -ne 's,^.*\(eb\)$,\1,p')
 		machine="${arch}${endian}"-unknown
 		;;
 	    *) machine="$UNAME_MACHINE_ARCH"-unknown ;;
@@ -220,7 +232,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	case "$UNAME_MACHINE_ARCH" in
 	    earm*)
 		expr='s/^earmv[0-9]/-eabi/;s/eb$//'
-		abi=`echo "$UNAME_MACHINE_ARCH" | sed -e "$expr"`
+		abi=$(echo "$UNAME_MACHINE_ARCH" | sed -e "$expr")
 		;;
 	esac
 	# The OS release
@@ -233,7 +245,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 		release='-gnu'
 		;;
 	    *)
-		release=`echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2`
+		release=$(echo "$UNAME_RELEASE" | sed -e 's/[-_].*//' | cut -d. -f1,2)
 		;;
 	esac
 	# Since CPU_TYPE-MANUFACTURER-KERNEL-OPERATING_SYSTEM:
@@ -242,15 +254,15 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	echo "$machine-${os}${release}${abi-}"
 	exit ;;
     *:Bitrig:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/Bitrig.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/Bitrig.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-bitrig"$UNAME_RELEASE"
 	exit ;;
     *:OpenBSD:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/OpenBSD.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/OpenBSD.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-openbsd"$UNAME_RELEASE"
 	exit ;;
     *:LibertyBSD:*:*)
-	UNAME_MACHINE_ARCH=`arch | sed 's/^.*BSD\.//'`
+	UNAME_MACHINE_ARCH=$(arch | sed 's/^.*BSD\.//')
 	echo "$UNAME_MACHINE_ARCH"-unknown-libertybsd"$UNAME_RELEASE"
 	exit ;;
     *:MidnightBSD:*:*)
@@ -262,6 +274,9 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
     *:SolidBSD:*:*)
 	echo "$UNAME_MACHINE"-unknown-solidbsd"$UNAME_RELEASE"
 	exit ;;
+    *:OS108:*:*)
+	echo "$UNAME_MACHINE"-unknown-os108_"$UNAME_RELEASE"
+	exit ;;
     macppc:MirBSD:*:*)
 	echo powerpc-unknown-mirbsd"$UNAME_RELEASE"
 	exit ;;
@@ -271,26 +286,29 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
     *:Sortix:*:*)
 	echo "$UNAME_MACHINE"-unknown-sortix
 	exit ;;
+    *:Twizzler:*:*)
+	echo "$UNAME_MACHINE"-unknown-twizzler
+	exit ;;
     *:Redox:*:*)
 	echo "$UNAME_MACHINE"-unknown-redox
 	exit ;;
     mips:OSF1:*.*)
-        echo mips-dec-osf1
-        exit ;;
+	echo mips-dec-osf1
+	exit ;;
     alpha:OSF1:*:*)
 	case $UNAME_RELEASE in
 	*4.0)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $3}'`
+		UNAME_RELEASE=$(/usr/sbin/sizer -v | awk '{print $3}')
 		;;
 	*5.*)
-		UNAME_RELEASE=`/usr/sbin/sizer -v | awk '{print $4}'`
+		UNAME_RELEASE=$(/usr/sbin/sizer -v | awk '{print $4}')
 		;;
 	esac
 	# According to Compaq, /usr/sbin/psrinfo has been available on
 	# OSF/1 and Tru64 systems produced since 1995.  I hope that
 	# covers most systems running today.  This code pipes the CPU
 	# types through head -n 1, so we only detect the type of CPU 0.
-	ALPHA_CPU_TYPE=`/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1`
+	ALPHA_CPU_TYPE=$(/usr/sbin/psrinfo -v | sed -n -e 's/^  The alpha \(.*\) processor.*$/\1/p' | head -n 1)
 	case "$ALPHA_CPU_TYPE" in
 	    "EV4 (21064)")
 		UNAME_MACHINE=alpha ;;
@@ -328,7 +346,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	# A Tn.n version is a released field test version.
 	# A Xn.n version is an unreleased experimental baselevel.
 	# 1.2 uses "1.2" for uname -r.
-	echo "$UNAME_MACHINE"-dec-osf"`echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`"
+	echo "$UNAME_MACHINE"-dec-osf"$(echo "$UNAME_RELEASE" | sed -e 's/^[PVTX]//' | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz)"
 	# Reset EXIT trap before exiting to avoid spurious non-zero exit code.
 	exitcode=$?
 	trap '' 0
@@ -362,7 +380,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	exit ;;
     Pyramid*:OSx*:*:* | MIS*:OSx*:*:* | MIS*:SMP_DC-OSx*:*:*)
 	# akee@wpdis03.wpafb.af.mil (Earle F. Ake) contributed MIS and NILE.
-	if test "`(/bin/universe) 2>/dev/null`" = att ; then
+	if test "$( (/bin/universe) 2>/dev/null)" = att ; then
 		echo pyramid-pyramid-sysv3
 	else
 		echo pyramid-pyramid-bsd
@@ -375,17 +393,17 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	echo sparc-icl-nx6
 	exit ;;
     DRS?6000:UNIX_SV:4.2*:7* | DRS?6000:isis:4.2*:7*)
-	case `/usr/bin/uname -p` in
+	case $(/usr/bin/uname -p) in
 	    sparc) echo sparc-icl-nx7; exit ;;
 	esac ;;
     s390x:SunOS:*:*)
-	echo "$UNAME_MACHINE"-ibm-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	echo "$UNAME_MACHINE"-ibm-solaris2"$(echo "$UNAME_RELEASE" | sed -e 's/[^.]*//')"
 	exit ;;
     sun4H:SunOS:5.*:*)
-	echo sparc-hal-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo sparc-hal-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
     sun4*:SunOS:5.*:* | tadpole*:SunOS:5.*:*)
-	echo sparc-sun-solaris2"`echo "$UNAME_RELEASE" | sed -e 's/[^.]*//'`"
+	echo sparc-sun-solaris2"$(echo "$UNAME_RELEASE" | sed -e 's/[^.]*//')"
 	exit ;;
     i86pc:AuroraUX:5.*:* | i86xen:AuroraUX:5.*:*)
 	echo i386-pc-auroraux"$UNAME_RELEASE"
@@ -396,7 +414,7 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	# If there is a compiler, see if it is configured for 64-bit objects.
 	# Note that the Sun cc does not turn __LP64__ into 1 like gcc does.
 	# This test works for both compilers.
-	if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
 	    if (echo '#ifdef __amd64'; echo IS_64BIT_ARCH; echo '#endif') | \
 		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
 		grep IS_64BIT_ARCH >/dev/null
@@ -404,30 +422,30 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 		SUN_ARCH=x86_64
 	    fi
 	fi
-	echo "$SUN_ARCH"-pc-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo "$SUN_ARCH"-pc-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
     sun4*:SunOS:6*:*)
 	# According to config.sub, this is the proper way to canonicalize
 	# SunOS6.  Hard to guess exactly what SunOS6 will be like, but
 	# it's likely to be more like Solaris than SunOS4.
-	echo sparc-sun-solaris3"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo sparc-sun-solaris3"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
     sun4*:SunOS:*:*)
-	case "`/usr/bin/arch -k`" in
+	case "$(/usr/bin/arch -k)" in
 	    Series*|S4*)
-		UNAME_RELEASE=`uname -v`
+		UNAME_RELEASE=$(uname -v)
 		;;
 	esac
 	# Japanese Language versions have a version number like `4.1.3-JL'.
-	echo sparc-sun-sunos"`echo "$UNAME_RELEASE"|sed -e 's/-/_/'`"
+	echo sparc-sun-sunos"$(echo "$UNAME_RELEASE"|sed -e 's/-/_/')"
 	exit ;;
     sun3*:SunOS:*:*)
 	echo m68k-sun-sunos"$UNAME_RELEASE"
 	exit ;;
     sun*:*:4.2BSD:*)
-	UNAME_RELEASE=`(sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null`
+	UNAME_RELEASE=$( (sed 1q /etc/motd | awk '{print substr($5,1,3)}') 2>/dev/null)
 	test "x$UNAME_RELEASE" = x && UNAME_RELEASE=3
-	case "`/bin/arch`" in
+	case "$(/bin/arch)" in
 	    sun3)
 		echo m68k-sun-sunos"$UNAME_RELEASE"
 		;;
@@ -507,8 +525,8 @@ case "$UNAME_MACHINE:$UNAME_SYSTEM:$UNAME_RELEASE:$UNAME_VERSION" in
 	}
 EOF
 	$CC_FOR_BUILD -o "$dummy" "$dummy.c" &&
-	  dummyarg=`echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p'` &&
-	  SYSTEM_NAME=`"$dummy" "$dummyarg"` &&
+	  dummyarg=$(echo "$UNAME_RELEASE" | sed -n 's/\([0-9]*\).*/\1/p') &&
+	  SYSTEM_NAME=$("$dummy" "$dummyarg") &&
 	    { echo "$SYSTEM_NAME"; exit; }
 	echo mips-mips-riscos"$UNAME_RELEASE"
 	exit ;;
@@ -535,11 +553,11 @@ EOF
 	exit ;;
     AViiON:dgux:*:*)
 	# DG/UX returns AViiON for all architectures
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
-	if [ "$UNAME_PROCESSOR" = mc88100 ] || [ "$UNAME_PROCESSOR" = mc88110 ]
+	UNAME_PROCESSOR=$(/usr/bin/uname -p)
+	if test "$UNAME_PROCESSOR" = mc88100 || test "$UNAME_PROCESSOR" = mc88110
 	then
-	    if [ "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx ] || \
-	       [ "$TARGET_BINARY_INTERFACE"x = x ]
+	    if test "$TARGET_BINARY_INTERFACE"x = m88kdguxelfx || \
+	       test "$TARGET_BINARY_INTERFACE"x = x
 	    then
 		echo m88k-dg-dgux"$UNAME_RELEASE"
 	    else
@@ -563,17 +581,17 @@ EOF
 	echo m68k-tektronix-bsd
 	exit ;;
     *:IRIX*:*:*)
-	echo mips-sgi-irix"`echo "$UNAME_RELEASE"|sed -e 's/-/_/g'`"
+	echo mips-sgi-irix"$(echo "$UNAME_RELEASE"|sed -e 's/-/_/g')"
 	exit ;;
     ????????:AIX?:[12].1:2)   # AIX 2.2.1 or AIX 2.1.1 is RT/PC AIX.
 	echo romp-ibm-aix     # uname -m gives an 8 hex-code CPU id
-	exit ;;               # Note that: echo "'`uname -s`'" gives 'AIX '
+	exit ;;               # Note that: echo "'$(uname -s)'" gives 'AIX '
     i*86:AIX:*:*)
 	echo i386-ibm-aix
 	exit ;;
     ia64:AIX:*:*)
-	if [ -x /usr/bin/oslevel ] ; then
-		IBM_REV=`/usr/bin/oslevel`
+	if test -x /usr/bin/oslevel ; then
+		IBM_REV=$(/usr/bin/oslevel)
 	else
 		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
 	fi
@@ -593,7 +611,7 @@ EOF
 			exit(0);
 			}
 EOF
-		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"`
+		if $CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=$("$dummy")
 		then
 			echo "$SYSTEM_NAME"
 		else
@@ -606,15 +624,15 @@ EOF
 	fi
 	exit ;;
     *:AIX:*:[4567])
-	IBM_CPU_ID=`/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }'`
+	IBM_CPU_ID=$(/usr/sbin/lsdev -C -c processor -S available | sed 1q | awk '{ print $1 }')
 	if /usr/sbin/lsattr -El "$IBM_CPU_ID" | grep ' POWER' >/dev/null 2>&1; then
 		IBM_ARCH=rs6000
 	else
 		IBM_ARCH=powerpc
 	fi
-	if [ -x /usr/bin/lslpp ] ; then
-		IBM_REV=`/usr/bin/lslpp -Lqc bos.rte.libc |
-			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/`
+	if test -x /usr/bin/lslpp ; then
+		IBM_REV=$(/usr/bin/lslpp -Lqc bos.rte.libc |
+			   awk -F: '{ print $3 }' | sed s/[0-9]*$/0/)
 	else
 		IBM_REV="$UNAME_VERSION.$UNAME_RELEASE"
 	fi
@@ -642,14 +660,14 @@ EOF
 	echo m68k-hp-bsd4.4
 	exit ;;
     9000/[34678]??:HP-UX:*:*)
-	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	HPUX_REV=$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//')
 	case "$UNAME_MACHINE" in
 	    9000/31?)            HP_ARCH=m68000 ;;
 	    9000/[34]??)         HP_ARCH=m68k ;;
 	    9000/[678][0-9][0-9])
-		if [ -x /usr/bin/getconf ]; then
-		    sc_cpu_version=`/usr/bin/getconf SC_CPU_VERSION 2>/dev/null`
-		    sc_kernel_bits=`/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null`
+		if test -x /usr/bin/getconf; then
+		    sc_cpu_version=$(/usr/bin/getconf SC_CPU_VERSION 2>/dev/null)
+		    sc_kernel_bits=$(/usr/bin/getconf SC_KERNEL_BITS 2>/dev/null)
 		    case "$sc_cpu_version" in
 		      523) HP_ARCH=hppa1.0 ;; # CPU_PA_RISC1_0
 		      528) HP_ARCH=hppa1.1 ;; # CPU_PA_RISC1_1
@@ -661,7 +679,7 @@ EOF
 			esac ;;
 		    esac
 		fi
-		if [ "$HP_ARCH" = "" ]; then
+		if test "$HP_ARCH" = ""; then
 		    set_cc_for_build
 		    sed 's/^		//' << EOF > "$dummy.c"
 
@@ -696,11 +714,11 @@ EOF
 		    exit (0);
 		}
 EOF
-		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=`"$dummy"`
+		    (CCOPTS="" $CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null) && HP_ARCH=$("$dummy")
 		    test -z "$HP_ARCH" && HP_ARCH=hppa
 		fi ;;
 	esac
-	if [ "$HP_ARCH" = hppa2.0w ]
+	if test "$HP_ARCH" = hppa2.0w
 	then
 	    set_cc_for_build
 
@@ -724,7 +742,7 @@ EOF
 	echo "$HP_ARCH"-hp-hpux"$HPUX_REV"
 	exit ;;
     ia64:HP-UX:*:*)
-	HPUX_REV=`echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//'`
+	HPUX_REV=$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*.[0B]*//')
 	echo ia64-hp-hpux"$HPUX_REV"
 	exit ;;
     3050*:HI-UX:*:*)
@@ -754,7 +772,7 @@ EOF
 	  exit (0);
 	}
 EOF
-	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=`"$dummy"` &&
+	$CC_FOR_BUILD -o "$dummy" "$dummy.c" && SYSTEM_NAME=$("$dummy") &&
 		{ echo "$SYSTEM_NAME"; exit; }
 	echo unknown-hitachi-hiuxwe2
 	exit ;;
@@ -774,7 +792,7 @@ EOF
 	echo hppa1.0-hp-osf
 	exit ;;
     i*86:OSF1:*:*)
-	if [ -x /usr/sbin/sysversion ] ; then
+	if test -x /usr/sbin/sysversion ; then
 	    echo "$UNAME_MACHINE"-unknown-osf1mk
 	else
 	    echo "$UNAME_MACHINE"-unknown-osf1
@@ -823,14 +841,14 @@ EOF
 	echo craynv-cray-unicosmp"$UNAME_RELEASE" | sed -e 's/\.[^.]*$/.X/'
 	exit ;;
     F30[01]:UNIX_System_V:*:* | F700:UNIX_System_V:*:*)
-	FUJITSU_PROC=`uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz`
-	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
-	FUJITSU_REL=`echo "$UNAME_RELEASE" | sed -e 's/ /_/'`
+	FUJITSU_PROC=$(uname -m | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz)
+	FUJITSU_SYS=$(uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///')
+	FUJITSU_REL=$(echo "$UNAME_RELEASE" | sed -e 's/ /_/')
 	echo "${FUJITSU_PROC}-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
 	exit ;;
     5000:UNIX_System_V:4.*:*)
-	FUJITSU_SYS=`uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///'`
-	FUJITSU_REL=`echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/'`
+	FUJITSU_SYS=$(uname -p | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/\///')
+	FUJITSU_REL=$(echo "$UNAME_RELEASE" | tr ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz | sed -e 's/ /_/')
 	echo "sparc-fujitsu-${FUJITSU_SYS}${FUJITSU_REL}"
 	exit ;;
     i*86:BSD/386:*:* | i*86:BSD/OS:*:* | *:Ascend\ Embedded/OS:*:*)
@@ -843,25 +861,25 @@ EOF
 	echo "$UNAME_MACHINE"-unknown-bsdi"$UNAME_RELEASE"
 	exit ;;
     arm:FreeBSD:*:*)
-	UNAME_PROCESSOR=`uname -p`
+	UNAME_PROCESSOR=$(uname -p)
 	set_cc_for_build
 	if echo __ARM_PCS_VFP | $CC_FOR_BUILD -E - 2>/dev/null \
 	    | grep -q __ARM_PCS_VFP
 	then
-	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`"-gnueabi
+	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"$(echo ${UNAME_RELEASE}|sed -e 's/[-(].*//')"-gnueabi
 	else
-	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"`echo ${UNAME_RELEASE}|sed -e 's/[-(].*//'`"-gnueabihf
+	    echo "${UNAME_PROCESSOR}"-unknown-freebsd"$(echo ${UNAME_RELEASE}|sed -e 's/[-(].*//')"-gnueabihf
 	fi
 	exit ;;
     *:FreeBSD:*:*)
-	UNAME_PROCESSOR=`/usr/bin/uname -p`
+	UNAME_PROCESSOR=$(/usr/bin/uname -p)
 	case "$UNAME_PROCESSOR" in
 	    amd64)
 		UNAME_PROCESSOR=x86_64 ;;
 	    i386)
 		UNAME_PROCESSOR=i586 ;;
 	esac
-	echo "$UNAME_PROCESSOR"-unknown-freebsd"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	echo "$UNAME_PROCESSOR"-unknown-freebsd"$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')"
 	exit ;;
     i*:CYGWIN*:*)
 	echo "$UNAME_MACHINE"-pc-cygwin
@@ -897,15 +915,15 @@ EOF
 	echo x86_64-pc-cygwin
 	exit ;;
     prep*:SunOS:5.*:*)
-	echo powerpcle-unknown-solaris2"`echo "$UNAME_RELEASE"|sed -e 's/[^.]*//'`"
+	echo powerpcle-unknown-solaris2"$(echo "$UNAME_RELEASE"|sed -e 's/[^.]*//')"
 	exit ;;
     *:GNU:*:*)
 	# the GNU system
-	echo "`echo "$UNAME_MACHINE"|sed -e 's,[-/].*$,,'`-unknown-$LIBC`echo "$UNAME_RELEASE"|sed -e 's,/.*$,,'`"
+	echo "$(echo "$UNAME_MACHINE"|sed -e 's,[-/].*$,,')-unknown-$LIBC$(echo "$UNAME_RELEASE"|sed -e 's,/.*$,,')"
 	exit ;;
     *:GNU/*:*:*)
 	# other systems with GNU libc and userland
-	echo "$UNAME_MACHINE-unknown-`echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]"``echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`-$LIBC"
+	echo "$UNAME_MACHINE-unknown-$(echo "$UNAME_SYSTEM" | sed 's,^[^/]*/,,' | tr "[:upper:]" "[:lower:]")$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')-$LIBC"
 	exit ;;
     *:Minix:*:*)
 	echo "$UNAME_MACHINE"-unknown-minix
@@ -918,7 +936,7 @@ EOF
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
     alpha:Linux:*:*)
-	case `sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' < /proc/cpuinfo` in
+	case $(sed -n '/^cpu model/s/^.*: \(.*\)/\1/p' /proc/cpuinfo 2>/dev/null) in
 	  EV5)   UNAME_MACHINE=alphaev5 ;;
 	  EV56)  UNAME_MACHINE=alphaev56 ;;
 	  PCA56) UNAME_MACHINE=alphapca56 ;;
@@ -977,6 +995,9 @@ EOF
     k1om:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
+    loongarch32:Linux:*:* | loongarch64:Linux:*:* | loongarchx32:Linux:*:*)
+	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
+	exit ;;
     m32r*:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
@@ -1027,7 +1048,7 @@ EOF
 	#endif
 	#endif
 EOF
-	eval "`$CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU\|^MIPS_ENDIAN\|^LIBCABI'`"
+	eval "$($CC_FOR_BUILD -E "$dummy.c" 2>/dev/null | grep '^CPU\|^MIPS_ENDIAN\|^LIBCABI')"
 	test "x$CPU" != x && { echo "$CPU${MIPS_ENDIAN}-unknown-linux-$LIBCABI"; exit; }
 	;;
     mips64el:Linux:*:*)
@@ -1047,7 +1068,7 @@ EOF
 	exit ;;
     parisc:Linux:*:* | hppa:Linux:*:*)
 	# Look for CPU level
-	case `grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2` in
+	case $(grep '^cpu[^a-z]*:' /proc/cpuinfo 2>/dev/null | cut -d' ' -f2) in
 	  PA7*) echo hppa1.1-unknown-linux-"$LIBC" ;;
 	  PA8*) echo hppa2.0-unknown-linux-"$LIBC" ;;
 	  *)    echo hppa-unknown-linux-"$LIBC" ;;
@@ -1065,7 +1086,7 @@ EOF
     ppcle:Linux:*:*)
 	echo powerpcle-unknown-linux-"$LIBC"
 	exit ;;
-    riscv32:Linux:*:* | riscv64:Linux:*:*)
+    riscv32:Linux:*:* | riscv32be:Linux:*:* | riscv64:Linux:*:* | riscv64be:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
 	exit ;;
     s390:Linux:*:* | s390x:Linux:*:*)
@@ -1087,7 +1108,17 @@ EOF
 	echo "$UNAME_MACHINE"-dec-linux-"$LIBC"
 	exit ;;
     x86_64:Linux:*:*)
-	echo "$UNAME_MACHINE"-pc-linux-"$LIBC"
+	set_cc_for_build
+	LIBCABI=$LIBC
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    if (echo '#ifdef __ILP32__'; echo IS_X32; echo '#endif') | \
+		(CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		grep IS_X32 >/dev/null
+	    then
+		LIBCABI="$LIBC"x32
+	    fi
+	fi
+	echo "$UNAME_MACHINE"-pc-linux-"$LIBCABI"
 	exit ;;
     xtensa*:Linux:*:*)
 	echo "$UNAME_MACHINE"-unknown-linux-"$LIBC"
@@ -1127,7 +1158,7 @@ EOF
 	echo "$UNAME_MACHINE"-pc-msdosdjgpp
 	exit ;;
     i*86:*:4.*:*)
-	UNAME_REL=`echo "$UNAME_RELEASE" | sed 's/\/MP$//'`
+	UNAME_REL=$(echo "$UNAME_RELEASE" | sed 's/\/MP$//')
 	if grep Novell /usr/include/link.h >/dev/null 2>/dev/null; then
 		echo "$UNAME_MACHINE"-univel-sysv"$UNAME_REL"
 	else
@@ -1136,7 +1167,7 @@ EOF
 	exit ;;
     i*86:*:5:[678]*)
 	# UnixWare 7.x, OpenUNIX and OpenServer 6.
-	case `/bin/uname -X | grep "^Machine"` in
+	case $(/bin/uname -X | grep "^Machine") in
 	    *486*)	     UNAME_MACHINE=i486 ;;
 	    *Pentium)	     UNAME_MACHINE=i586 ;;
 	    *Pent*|*Celeron) UNAME_MACHINE=i686 ;;
@@ -1145,10 +1176,10 @@ EOF
 	exit ;;
     i*86:*:3.2:*)
 	if test -f /usr/options/cb.name; then
-		UNAME_REL=`sed -n 's/.*Version //p' </usr/options/cb.name`
+		UNAME_REL=$(sed -n 's/.*Version //p' </usr/options/cb.name)
 		echo "$UNAME_MACHINE"-pc-isc"$UNAME_REL"
 	elif /bin/uname -X 2>/dev/null >/dev/null ; then
-		UNAME_REL=`(/bin/uname -X|grep Release|sed -e 's/.*= //')`
+		UNAME_REL=$( (/bin/uname -X|grep Release|sed -e 's/.*= //'))
 		(/bin/uname -X|grep i80486 >/dev/null) && UNAME_MACHINE=i486
 		(/bin/uname -X|grep '^Machine.*Pentium' >/dev/null) \
 			&& UNAME_MACHINE=i586
@@ -1198,7 +1229,7 @@ EOF
     3[345]??:*:4.0:3.0 | 3[34]??A:*:4.0:3.0 | 3[34]??,*:*:4.0:3.0 | 3[34]??/*:*:4.0:3.0 | 4400:*:4.0:3.0 | 4850:*:4.0:3.0 | SKA40:*:4.0:3.0 | SDS2:*:4.0:3.0 | SHG2:*:4.0:3.0 | S7501*:*:4.0:3.0)
 	OS_REL=''
 	test -r /etc/.relid \
-	&& OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	&& OS_REL=.$(sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid)
 	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
 	  && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
 	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
@@ -1209,7 +1240,7 @@ EOF
     NCR*:*:4.2:* | MPRAS*:*:4.2:*)
 	OS_REL='.3'
 	test -r /etc/.relid \
-	    && OS_REL=.`sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid`
+	    && OS_REL=.$(sed -n 's/[^ ]* [^ ]* \([0-9][0-9]\).*/\1/p' < /etc/.relid)
 	/bin/uname -p 2>/dev/null | grep 86 >/dev/null \
 	    && { echo i486-ncr-sysv4.3"$OS_REL"; exit; }
 	/bin/uname -p 2>/dev/null | /bin/grep entium >/dev/null \
@@ -1242,7 +1273,7 @@ EOF
 	exit ;;
     *:SINIX-*:*:*)
 	if uname -p 2>/dev/null >/dev/null ; then
-		UNAME_MACHINE=`(uname -p) 2>/dev/null`
+		UNAME_MACHINE=$( (uname -p) 2>/dev/null)
 		echo "$UNAME_MACHINE"-sni-sysv4
 	else
 		echo ns32k-sni-sysv
@@ -1276,7 +1307,7 @@ EOF
 	echo mips-sony-newsos6
 	exit ;;
     R[34]000:*System_V*:*:* | R4000:UNIX_SYSV:*:* | R*000:UNIX_SV:*:*)
-	if [ -d /usr/nec ]; then
+	if test -d /usr/nec; then
 		echo mips-nec-sysv"$UNAME_RELEASE"
 	else
 		echo mips-unknown-sysv"$UNAME_RELEASE"
@@ -1324,44 +1355,48 @@ EOF
     *:Rhapsody:*:*)
 	echo "$UNAME_MACHINE"-apple-rhapsody"$UNAME_RELEASE"
 	exit ;;
+    arm64:Darwin:*:*)
+	echo aarch64-apple-darwin"$UNAME_RELEASE"
+	exit ;;
     *:Darwin:*:*)
-	UNAME_PROCESSOR=`uname -p` || UNAME_PROCESSOR=unknown
-	set_cc_for_build
-	if test "$UNAME_PROCESSOR" = unknown ; then
-	    UNAME_PROCESSOR=powerpc
+	UNAME_PROCESSOR=$(uname -p)
+	case $UNAME_PROCESSOR in
+	    unknown) UNAME_PROCESSOR=powerpc ;;
+	esac
+	if command -v xcode-select > /dev/null 2> /dev/null && \
+		! xcode-select --print-path > /dev/null 2> /dev/null ; then
+	    # Avoid executing cc if there is no toolchain installed as
+	    # cc will be a stub that puts up a graphical alert
+	    # prompting the user to install developer tools.
+	    CC_FOR_BUILD=no_compiler_found
+	else
+	    set_cc_for_build
 	fi
-	if test "`echo "$UNAME_RELEASE" | sed -e 's/\..*//'`" -le 10 ; then
-	    if [ "$CC_FOR_BUILD" != no_compiler_found ]; then
-		if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       grep IS_64BIT_ARCH >/dev/null
-		then
-		    case $UNAME_PROCESSOR in
-			i386) UNAME_PROCESSOR=x86_64 ;;
-			powerpc) UNAME_PROCESSOR=powerpc64 ;;
-		    esac
-		fi
-		# On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
-		if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
-		       (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
-		       grep IS_PPC >/dev/null
-		then
-		    UNAME_PROCESSOR=powerpc
-		fi
+	if test "$CC_FOR_BUILD" != no_compiler_found; then
+	    if (echo '#ifdef __LP64__'; echo IS_64BIT_ARCH; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_64BIT_ARCH >/dev/null
+	    then
+		case $UNAME_PROCESSOR in
+		    i386) UNAME_PROCESSOR=x86_64 ;;
+		    powerpc) UNAME_PROCESSOR=powerpc64 ;;
+		esac
+	    fi
+	    # On 10.4-10.6 one might compile for PowerPC via gcc -arch ppc
+	    if (echo '#ifdef __POWERPC__'; echo IS_PPC; echo '#endif') | \
+		   (CCOPTS="" $CC_FOR_BUILD -E - 2>/dev/null) | \
+		   grep IS_PPC >/dev/null
+	    then
+		UNAME_PROCESSOR=powerpc
 	    fi
 	elif test "$UNAME_PROCESSOR" = i386 ; then
-	    # Avoid executing cc on OS X 10.9, as it ships with a stub
-	    # that puts up a graphical alert prompting to install
-	    # developer tools.  Any system running Mac OS X 10.7 or
-	    # later (Darwin 11 and later) is required to have a 64-bit
-	    # processor. This is not true of the ARM version of Darwin
-	    # that Apple uses in portable devices.
-	    UNAME_PROCESSOR=x86_64
+	    # uname -m returns i386 or x86_64
+	    UNAME_PROCESSOR=$UNAME_MACHINE
 	fi
 	echo "$UNAME_PROCESSOR"-apple-darwin"$UNAME_RELEASE"
 	exit ;;
     *:procnto*:*:* | *:QNX:[0123456789]*:*)
-	UNAME_PROCESSOR=`uname -p`
+	UNAME_PROCESSOR=$(uname -p)
 	if test "$UNAME_PROCESSOR" = x86; then
 		UNAME_PROCESSOR=i386
 		UNAME_MACHINE=pc
@@ -1429,10 +1464,10 @@ EOF
 	echo mips-sei-seiux"$UNAME_RELEASE"
 	exit ;;
     *:DragonFly:*:*)
-	echo "$UNAME_MACHINE"-unknown-dragonfly"`echo "$UNAME_RELEASE"|sed -e 's/[-(].*//'`"
+	echo "$UNAME_MACHINE"-unknown-dragonfly"$(echo "$UNAME_RELEASE"|sed -e 's/[-(].*//')"
 	exit ;;
     *:*VMS:*:*)
-	UNAME_MACHINE=`(uname -p) 2>/dev/null`
+	UNAME_MACHINE=$( (uname -p) 2>/dev/null)
 	case "$UNAME_MACHINE" in
 	    A*) echo alpha-dec-vms ; exit ;;
 	    I*) echo ia64-dec-vms ; exit ;;
@@ -1442,13 +1477,13 @@ EOF
 	echo i386-pc-xenix
 	exit ;;
     i*86:skyos:*:*)
-	echo "$UNAME_MACHINE"-pc-skyos"`echo "$UNAME_RELEASE" | sed -e 's/ .*$//'`"
+	echo "$UNAME_MACHINE"-pc-skyos"$(echo "$UNAME_RELEASE" | sed -e 's/ .*$//')"
 	exit ;;
     i*86:rdos:*:*)
 	echo "$UNAME_MACHINE"-pc-rdos
 	exit ;;
-    i*86:AROS:*:*)
-	echo "$UNAME_MACHINE"-pc-aros
+    *:AROS:*:*)
+	echo "$UNAME_MACHINE"-unknown-aros
 	exit ;;
     x86_64:VMkernel:*:*)
 	echo "$UNAME_MACHINE"-unknown-esx
@@ -1468,6 +1503,14 @@ cat > "$dummy.c" <<EOF
 #include <sys/types.h>
 #include <sys/utsname.h>
 #endif
+#if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
+#if defined (vax) || defined (__vax) || defined (__vax__) || defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
+#include <signal.h>
+#if defined(_SIZE_T_) || defined(SIGLOST)
+#include <sys/utsname.h>
+#endif
+#endif
+#endif
 main ()
 {
 #if defined (sony)
@@ -1492,7 +1535,7 @@ main ()
 #define __ARCHITECTURE__ "m68k"
 #endif
   int version;
-  version=`(hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null`;
+  version=$( (hostinfo | sed -n 's/.*NeXT Mach \([0-9]*\).*/\1/p') 2>/dev/null);
   if (version < 4)
     printf ("%s-next-nextstep%d\n", __ARCHITECTURE__, version);
   else
@@ -1554,19 +1597,24 @@ main ()
 #else
   printf ("vax-dec-bsd\n"); exit (0);
 #endif
+#else
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname un;
+  uname (&un);
+  printf ("vax-dec-ultrix%s\n", un.release); exit (0);
 #else
   printf ("vax-dec-ultrix\n"); exit (0);
 #endif
 #endif
+#endif
 #if defined(ultrix) || defined(_ultrix) || defined(__ultrix) || defined(__ultrix__)
 #if defined(mips) || defined(__mips) || defined(__mips__) || defined(MIPS) || defined(__MIPS__)
-#include <signal.h>
-#if defined(_SIZE_T_) /* >= ULTRIX4 */
-  printf ("mips-dec-ultrix4\n"); exit (0);
+#if defined(_SIZE_T_) || defined(SIGLOST)
+  struct utsname *un;
+  uname (&un);
+  printf ("mips-dec-ultrix%s\n", un.release); exit (0);
 #else
-#if defined(ULTRIX3) || defined(ultrix3) || defined(SIGLOST)
-  printf ("mips-dec-ultrix3\n"); exit (0);
-#endif
+  printf ("mips-dec-ultrix\n"); exit (0);
 #endif
 #endif
 #endif
@@ -1579,7 +1627,7 @@ main ()
 }
 EOF
 
-$CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null && SYSTEM_NAME=`$dummy` &&
+$CC_FOR_BUILD -o "$dummy" "$dummy.c" 2>/dev/null && SYSTEM_NAME=$($dummy) &&
 	{ echo "$SYSTEM_NAME"; exit; }
 
 # Apollos put the system type in the environment.
@@ -1604,9 +1652,15 @@ This script (version $timestamp), has failed to recognize the
 operating system you are using. If your script is old, overwrite *all*
 copies of config.guess and config.sub with the latest versions from:
 
-  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.guess
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.guess
 and
-  https://git.savannah.gnu.org/gitweb/?p=config.git;a=blob_plain;f=config.sub
+  https://git.savannah.gnu.org/cgit/config.git/plain/config.sub
+EOF
+
+year=$(echo $timestamp | sed 's,-.*,,')
+# shellcheck disable=SC2003
+if test "$(expr "$(date +%Y)" - "$year")" -lt 3 ; then
+   cat >&2 <<EOF
 
 If $0 has already been updated, send the following data and any
 information you think might be pertinent to config-patches@gnu.org to
@@ -1614,26 +1668,27 @@ provide the necessary information to handle your system.
 
 config.guess timestamp = $timestamp
 
-uname -m = `(uname -m) 2>/dev/null || echo unknown`
-uname -r = `(uname -r) 2>/dev/null || echo unknown`
-uname -s = `(uname -s) 2>/dev/null || echo unknown`
-uname -v = `(uname -v) 2>/dev/null || echo unknown`
+uname -m = $( (uname -m) 2>/dev/null || echo unknown)
+uname -r = $( (uname -r) 2>/dev/null || echo unknown)
+uname -s = $( (uname -s) 2>/dev/null || echo unknown)
+uname -v = $( (uname -v) 2>/dev/null || echo unknown)
 
-/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null`
-/bin/uname -X     = `(/bin/uname -X) 2>/dev/null`
+/usr/bin/uname -p = $( (/usr/bin/uname -p) 2>/dev/null)
+/bin/uname -X     = $( (/bin/uname -X) 2>/dev/null)
 
-hostinfo               = `(hostinfo) 2>/dev/null`
-/bin/universe          = `(/bin/universe) 2>/dev/null`
-/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null`
-/bin/arch              = `(/bin/arch) 2>/dev/null`
-/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null`
-/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null`
+hostinfo               = $( (hostinfo) 2>/dev/null)
+/bin/universe          = $( (/bin/universe) 2>/dev/null)
+/usr/bin/arch -k       = $( (/usr/bin/arch -k) 2>/dev/null)
+/bin/arch              = $( (/bin/arch) 2>/dev/null)
+/usr/bin/oslevel       = $( (/usr/bin/oslevel) 2>/dev/null)
+/usr/convex/getsysinfo = $( (/usr/convex/getsysinfo) 2>/dev/null)
 
 UNAME_MACHINE = "$UNAME_MACHINE"
 UNAME_RELEASE = "$UNAME_RELEASE"
 UNAME_SYSTEM  = "$UNAME_SYSTEM"
 UNAME_VERSION = "$UNAME_VERSION"
 EOF
+fi
 
 exit 1
 

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

@@ -5,7 +5,7 @@
 # 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)
 
@@ -16,6 +16,7 @@ if test -s "`which hg`" && test -d "$srcdir/.hg"; then
 fi
 
 ORIGCFLAGS="$CFLAGS"
+LATE_CFLAGS=""
 # Checks for programs.
 AC_PROG_CC
 
@@ -47,6 +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],
@@ -124,6 +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
 
@@ -347,6 +362,7 @@ AC_ARG_ENABLE(fuzz,
             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)
@@ -364,7 +380,6 @@ 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 \
@@ -379,7 +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])
@@ -859,8 +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()

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 

dbmalloc.h

@@ -1,9 +1,9 @@
 #ifndef DBMALLOC_H_
 #define DBMALLOC_H_
 
-#include "stdint.h"
-#include "stdlib.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);

dbrandom.c

@@ -150,12 +150,12 @@ static void write_urandom()
 }
 
 #if DROPBEAR_FUZZ
-void fuzz_seed(void) {
+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;
 }

dbutil.c

@@ -385,20 +385,37 @@ 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) {
@@ -566,8 +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)
@@ -585,11 +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;
 		}
 	}
@@ -691,3 +723,22 @@ void fsync_parent_dir(const char* fn) {
 	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

@@ -90,6 +90,8 @@ 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)

default_options.h

@@ -126,9 +126,11 @@ 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
@@ -256,6 +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"

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
@@ -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.

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++) {

ed25519.c

@@ -38,14 +38,25 @@
  * 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) {
+int buf_get_ed25519_pub_key(buffer *buf, dropbear_ed25519_key *key,
+	enum signkey_type expect_keytype) {
 
-	unsigned int len;
+
+	unsigned int len, typelen;
+	char *keytype = NULL;
+	enum signkey_type buf_keytype;
 
 	TRACE(("enter buf_get_ed25519_pub_key"))
 	dropbear_assert(key != NULL);
 
-	buf_incrpos(buf, 4+SSH_SIGNKEY_ED25519_LEN); /* int + "ssh-ed25519" */
+	/* 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) {

ed25519.h

@@ -27,6 +27,7 @@
 
 #include "includes.h"
 #include "buffer.h"
+#include "signkey.h"
 
 #if DROPBEAR_ED25519 
 
@@ -43,7 +44,8 @@ void buf_put_ed25519_sign(buffer* buf, const dropbear_ed25519_key *key, const bu
 #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);
+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);

fuzz-wrapfd.h

@@ -1,17 +1,20 @@
 #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();
+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);
@@ -19,5 +22,6 @@ 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

@@ -8,6 +8,7 @@
 #include "includes.h"
 #include "buffer.h"
 #include "algo.h"
+#include "netio.h"
 #include "fuzz-wrapfd.h"
 
 // once per process
@@ -15,11 +16,15 @@ 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_preauth(const uint8_t *Data, size_t Size, int skip_kexmaths);
+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);
 
@@ -29,7 +34,11 @@ 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(void);
+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,
@@ -45,6 +54,7 @@ void fuzz_dump(const unsigned char* data, size_t len);
 #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 {
@@ -58,20 +68,47 @@ struct dropbear_fuzz_options {
 
     // 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's set
+    // 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;
 
-#endif // DROPBEAR_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

@@ -1,7 +1,8 @@
+#define FUZZ_NO_REPLACE_STDERR
+#define FUZZ_NO_REPLACE_GETPW
 #include "includes.h"
 
 #include "includes.h"
-#include "fuzz.h"
 #include "dbutil.h"
 #include "runopts.h"
 #include "crypto_desc.h"
@@ -10,6 +11,7 @@
 #include "bignum.h"
 #include "atomicio.h"
 #include "fuzz-wrapfd.h"
+#include "fuzz.h"
 
 struct dropbear_fuzz_options fuzz;
 
@@ -17,6 +19,12 @@ static void fuzz_dropbear_log(int UNUSED(priority), const char* format, va_list
 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;
@@ -25,9 +33,25 @@ void fuzz_common_setup(void) {
     fuzz.input = m_malloc(sizeof(buffer));
     _dropbear_log = fuzz_dropbear_log;
     crypto_init();
-    fuzz_seed();
+    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) {
@@ -41,8 +65,9 @@ int fuzz_set_input(const uint8_t *Data, size_t Size) {
     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_seed(fuzz.input->data, MIN(fuzz.input->len, 16));
 
     return DROPBEAR_SUCCESS;
 }
@@ -77,6 +102,13 @@ void fuzz_svr_setup(void) {
     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();
     
@@ -164,6 +196,7 @@ static void load_fixed_hostkeys(void) {
 
 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,
@@ -192,16 +225,43 @@ void fuzz_fake_send_kexdh_reply(void) {
 
 /* 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();
-    *ret_readfd = wrapfd_new();
+    *ret_writefd = wrapfd_new_dummy();
+    *ret_readfd = wrapfd_new_dummy();
     if (ret_errfd) {
-        *ret_errfd = wrapfd_new();
+        *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;
+
     }
-    *ret_pid = 999;
-    return DROPBEAR_SUCCESS;
 }
 
-int fuzz_run_preauth(const uint8_t *Data, size_t Size, int skip_kexmaths) {
+/* 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();
@@ -209,36 +269,25 @@ int fuzz_run_preauth(const uint8_t *Data, size_t Size, int skip_kexmaths) {
         once = 1;
     }
 
+    fuzz.svr_postauth = postauth;
+
     if (fuzz_set_input(Data, Size) == DROPBEAR_FAILURE) {
         return 0;
     }
 
-    /*
-      get prefix, allowing for future extensibility. input format is
-      string prefix
-          uint32 wrapfd seed
-          ... to be extended later
-      [bytes] ssh input stream
-    */
-
-    /* be careful to avoid triggering buffer.c assertions */
-    if (fuzz.input->len < 8) {
-        return 0;
-    }
-    size_t prefix_size = buf_getint(fuzz.input);
-    if (prefix_size != 4) {
-        return 0;
-    }
-    uint32_t wrapseed = buf_getint(fuzz.input);
+    uint32_t wrapseed;
+    genrandom((void*)&wrapseed, sizeof(wrapseed));
     wrapfd_setseed(wrapseed);
 
-    int fakesock = wrapfd_new();
+    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 */
@@ -259,32 +308,22 @@ int fuzz_run_client(const uint8_t *Data, size_t Size, int skip_kexmaths) {
         return 0;
     }
 
-    /*
-      get prefix, allowing for future extensibility. input format is
-      string prefix
-          uint32 wrapfd seed
-          ... to be extended later
-      [bytes] ssh input stream
-    */
+    // Allow to proceed sooner
+    ses.kexstate.donefirstkex = 1;
 
-    /* be careful to avoid triggering buffer.c assertions */
-    if (fuzz.input->len < 8) {
-        return 0;
-    }
-    size_t prefix_size = buf_getint(fuzz.input);
-    if (prefix_size != 4) {
-        return 0;
-    }
-    uint32_t wrapseed = buf_getint(fuzz.input);
+    uint32_t wrapseed;
+    genrandom((void*)&wrapseed, sizeof(wrapseed));
     wrapfd_setseed(wrapseed);
 
-    int fakesock = wrapfd_new();
+    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 */
@@ -304,8 +343,56 @@ const void* fuzz_get_algo(const algo_type *algos, const char* name) {
 }
 
 void fuzz_dump(const unsigned char* data, size_t len) {
-    TRACE(("dump %zu", 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

@@ -7,6 +7,7 @@ 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
@@ -15,6 +16,10 @@ int main(int argc, char ** argv) {
             TRACE(("debug printing on"))
         }
 #endif
+        if (strcmp(argv[i], "-q") == 0) {
+            printf("Running quiet\n");
+            quiet = 1;
+        }
     }
 
     int old_fuzz_wrapfds = 0;
@@ -31,11 +36,17 @@ int main(int argc, char ** argv) {
 
 		/* Run twice to catch problems with statefulness */
         fuzz.wrapfds = old_fuzz_wrapfds;
-        printf("Running %s once \n", fn);
+        if (!quiet) {
+            printf("Running %s once \n", fn);
+        }
         LLVMFuzzerTestOneInput(input->data, input->len);
-        printf("Running %s twice \n", fn);
+        if (!quiet) {
+            printf("Running %s twice \n", fn);
+        }
         LLVMFuzzerTestOneInput(input->data, input->len);
-        printf("Done %s\n", fn);
+        if (!quiet) {
+            printf("Done %s\n", fn);
+        }
 
         /* Disable wrapfd so it won't interfere with buf_readfile() above */
         old_fuzz_wrapfds = fuzz.wrapfds;
@@ -46,3 +57,10 @@ int main(int argc, char ** argv) {
 
     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-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

@@ -35,7 +35,7 @@ void wrapfd_setup(buffer *buf) {
 	// clean old ones
 	int i;
 	for (i = 0; i <= wrapfd_maxfd; i++) {
-		if (wrap_fds[i].mode == COMMONBUF) {
+		if (wrap_fds[i].mode != UNUSED) {
 			wrapfd_remove(i);
 		}
 	}
@@ -51,7 +51,7 @@ void wrapfd_setseed(uint32_t seed) {
 	nrand48(rand_state);
 }
 
-int wrapfd_new() {
+int wrapfd_new_fuzzinput() {
 	if (devnull_fd == -1) {
 		devnull_fd = open("/dev/null", O_RDONLY);
 		assert(devnull_fd != -1);
@@ -68,13 +68,38 @@ int wrapfd_new() {
 	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;
-	m_close(fd);
+	close(fd);
 }
 
 int wrapfd_close(int fd) {
@@ -113,7 +138,7 @@ int wrapfd_read(int fd, void *out, size_t count) {
 		return -1;
 	}
 
-	if (input_buf) {
+	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) {
@@ -124,6 +149,7 @@ int wrapfd_read(int fd, void *out, size_t count) {
 		return maxread;
 	}
 
+	// return fixed output, of random length
 	maxread = MIN(MAX_RANDOM_IN, count);
 	maxread = nrand48(rand_state) % maxread + 1;
 	memset(out, 0xef, maxread);
@@ -239,3 +265,15 @@ int wrapfd_select(int nfds, fd_set *readfds, fd_set *writefds,
 	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-kexcurve25519.c

@@ -6,33 +6,30 @@
 #include "algo.h"
 #include "bignum.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-	static int once = 0;
-	static struct key_context* keep_newkeys = NULL;
-	/* number of generated parameters is limited by the timeout for the first run.
-	   TODO move this to the libfuzzer initialiser function instead if the timeout
-	   doesn't apply there */
-	#define NUM_PARAMS 20
-	static struct kex_curve25519_param *curve25519_params[NUM_PARAMS];
+static struct key_context* keep_newkeys = NULL;
+/* An arbitrary limit */
+#define NUM_PARAMS 80
+static struct kex_curve25519_param *curve25519_params[NUM_PARAMS];
 
-	if (!once) {
-		fuzz_common_setup();
-		fuzz_svr_setup();
+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;
+	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();
-		}
-
-		once = 1;
+	/* 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;
 	}

fuzz/fuzzer-kexdh.c

@@ -6,33 +6,29 @@
 #include "algo.h"
 #include "bignum.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-	static int once = 0;
-	static struct key_context* keep_newkeys = NULL;
-	/* number of generated parameters is limited by the timeout for the first run.
-	   TODO move this to the libfuzzer initialiser function instead if the timeout
-	   doesn't apply there */
-	#define NUM_PARAMS 20
-	static struct kex_dh_param *dh_params[NUM_PARAMS];
+static struct key_context* keep_newkeys = NULL;
+#define NUM_PARAMS 80
+static struct kex_dh_param *dh_params[NUM_PARAMS];
 
-	if (!once) {
-		fuzz_common_setup();
-		fuzz_svr_setup();
+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;
+	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();
-		}
-
-		once = 1;
+	/* 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;
 	}

fuzz/fuzzer-kexecdh.c

@@ -6,38 +6,38 @@
 #include "algo.h"
 #include "bignum.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
-	static int once = 0;
-	static const struct dropbear_kex *ecdh[3]; /* 256, 384, 521 */
-	static struct key_context* keep_newkeys = NULL;
-	/* number of generated parameters is limited by the timeout for the first run */
-	#define NUM_PARAMS 80
-	static struct kex_ecdh_param *ecdh_params[NUM_PARAMS];
+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];
 
-	if (!once) {
-		fuzz_common_setup();
-		fuzz_svr_setup();
+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;
+	/* 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();
-		}
-
-		once = 1;
+	/* 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;

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

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

fuzz/fuzzer-preauth_nomaths.c

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

fuzz/fuzzer-pubkey.c

@@ -27,7 +27,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
 		unsigned int algolen;
 		char* algoname = buf_getstring(keyblob, &algolen);
 
-		if (signature_type_from_name(algoname, algolen) == DROPBEAR_SIGNKEY_NONE) {
+		if (signature_type_from_name(algoname, algolen) == DROPBEAR_SIGNATURE_NONE) {
 			dropbear_exit("fuzzer imagined a bogus algorithm");
 		}
 

fuzzers_test.sh

@@ -6,7 +6,9 @@ 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
-    ./$f fuzzcorpus/$f/* || result=1
+    # 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

includes.h

@@ -25,9 +25,6 @@
 #ifndef DROPBEAR_INCLUDES_H_
 #define DROPBEAR_INCLUDES_H_
 
-/* uclibc needs _GNU_SOURCE, maybe other things? */
-#define _GNU_SOURCE
-
 #include "options.h"
 #include "debug.h"
 

listener.c

@@ -139,7 +139,7 @@ struct Listener * get_listener(int type, const void* typedata,
 	struct Listener* listener;
 
 	for (i = 0, listener = ses.listeners[i]; i < ses.listensize; i++) {
-		if (listener->type == type
+		if (listener && listener->type == type
 				&& match(typedata, listener->typedata)) {
 			return listener;
 		}

netio.c

@@ -188,6 +188,13 @@ struct dropbear_progress_connection *connect_remote(const char* remotehost, cons
 
 	list_append(&ses.conn_pending, c);
 
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		c->errstring = m_strdup("fuzzing connect_remote always fails");
+		return c;
+	}
+#endif
+
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_socktype = SOCK_STREAM;
 	hints.ai_family = AF_UNSPEC;
@@ -453,8 +460,16 @@ int dropbear_listen(const char* address, const char* port,
 	struct linger linger;
 	int val;
 	int sock;
-
+	uint16_t *allocated_lport_p = NULL;
+	int allocated_lport = 0;
+	
 	TRACE(("enter dropbear_listen"))
+
+#if DROPBEAR_FUZZ
+	if (fuzz.fuzzing) {
+		return fuzz_dropbear_listen(address, port, socks, sockcount, errstring, maxfd);
+	}
+#endif
 	
 	memset(&hints, 0, sizeof(hints));
 	hints.ai_family = AF_UNSPEC; /* TODO: let them flag v4 only etc */
@@ -490,20 +505,15 @@ int dropbear_listen(const char* address, const char* port,
 		return -1;
 	}
 
-	/*
-	 * when listening on server-assigned-port 0
+	/* When listening on server-assigned-port 0
 	 * the assigned ports may differ for address families (v4/v6)
-	 * causing problems for tcpip-forward
-	 * caller can do a get_socket_address to discover assigned-port
-	 * hence, use same port for all address families
-	 */
-	u_int16_t *allocated_lport_p = NULL;
-	int allocated_lport = 0;
-
+	 * causing problems for tcpip-forward.
+	 * Caller can do a get_socket_address to discover assigned-port
+	 * hence, use same port for all address families */
+	allocated_lport = 0;
 	nsock = 0;
 	for (res = res0; res != NULL && nsock < sockcount;
 			res = res->ai_next) {
-
 		if (allocated_lport > 0) {
 			if (AF_INET == res->ai_family) {
 				allocated_lport_p = &((struct sockaddr_in *)res->ai_addr)->sin_port;
@@ -514,11 +524,8 @@ int dropbear_listen(const char* address, const char* port,
 		}
 
 		/* Get a socket */
-		socks[nsock] = socket(res->ai_family, res->ai_socktype,
-				res->ai_protocol);
-
+		socks[nsock] = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
 		sock = socks[nsock]; /* For clarity */
-
 		if (sock < 0) {
 			err = errno;
 			TRACE(("socket() failed"))
@@ -542,7 +549,6 @@ int dropbear_listen(const char* address, const char* port,
 			}
 		}
 #endif
-
 		set_sock_nodelay(sock);
 
 		if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
@@ -564,7 +570,6 @@ int dropbear_listen(const char* address, const char* port,
 		}
 
 		*maxfd = MAX(*maxfd, sock);
-
 		nsock++;
 	}
 

release.sh

@@ -1,4 +1,7 @@
 #!/bin/sh
+
+set -e
+
 VERSION=$(echo '#include "sysoptions.h"\necho DROPBEAR_VERSION' | cpp - | sh)
 echo Releasing version "$VERSION" ...
 if ! head -n1 CHANGES | grep -q $VERSION ; then
@@ -13,7 +16,11 @@ fi
 
 head -n1 CHANGES
 
-#sleep 3
+if tar --version | grep -q 'GNU tar'; then
+	TAR=tar
+else
+	TAR=gtar
+fi
 
 RELDIR=$PWD/../dropbear-$VERSION
 ARCHIVE=${RELDIR}.tar.bz2
@@ -29,13 +36,17 @@ fi
 
 hg archive "$RELDIR"  || exit 2
 
-(cd "$RELDIR" && autoconf && autoheader) || exit 2
-
-rm -r "$RELDIR/autom4te.cache" || exit 2
-
 rm "$RELDIR/.hgtags"
+# .hg_archival.txt seems to differ between hg versions, isn't good for reproducibility
+rm "$RELDIR/.hg_archival.txt"
 
-(cd "$RELDIR/.." && tar cjf $ARCHIVE `basename "$RELDIR"`) || exit 2
+RELDATE=$(head -n1 CHANGES | cut -d - -f 2)
+# timezone keeps it consistent, choose a plausible release time
+RELTIME="22:30:00 +0800"
+
+# from https://reproducible-builds.org/docs/archives/
+TAROPTS="--sort=name --owner=0 --group=0 --numeric-owner"
+(cd "$RELDIR/.." && $TAR cjf $ARCHIVE $TAROPTS --mtime="$RELDATE $RELTIME" `basename "$RELDIR"`) || exit 2
 
 ls -l $ARCHIVE
 openssl sha256 $ARCHIVE

runopts.h

@@ -130,6 +130,8 @@ typedef struct svr_runopts {
         char *pubkey_plugin_options;
 #endif
 
+	int pass_on_env;
+
 } svr_runopts;
 
 extern svr_runopts svr_opts;
@@ -159,6 +161,7 @@ typedef struct cli_runopts {
 #if DROPBEAR_CLI_ANYTCPFWD
 	int exit_on_fwd_failure;
 #endif
+	int disable_trivial_auth;
 #if DROPBEAR_CLI_REMOTETCPFWD
 	m_list * remotefwds;
 #endif
@@ -192,5 +195,6 @@ void parse_ciphers_macs(void);
 #endif
 
 void print_version(void);
+void parse_recv_window(const char* recv_window_arg);
 
 #endif /* DROPBEAR_RUNOPTS_H_ */

scp.c

@@ -185,7 +185,7 @@ arg_setup(char *host, char *remuser, char *cmd)
 }
 
 int
-do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout, int argc)
+do_cmd(char *host, char *remuser, char *cmd, int *fdin, int *fdout)
 {
 	int pin[2], pout[2], reserved[2];
 
@@ -532,8 +532,7 @@ toremote(char *targ, int argc, char **argv)
 				bp = xmalloc(len);
 				(void) snprintf(bp, len, "%s -t %s", cmd, targ);
 				host = cleanhostname(thost);
-				if (do_cmd(host, tuser, bp, &remin,
-				    &remout, argc) < 0)
+				if (do_cmd(host, tuser, bp, &remin, &remout) < 0)
 					exit(1);
 				if (response() < 0)
 					exit(1);
@@ -584,7 +583,7 @@ tolocal(int argc, char **argv)
 		len = strlen(src) + CMDNEEDS + 20;
 		bp = xmalloc(len);
 		(void) snprintf(bp, len, "%s -f %s", cmd, src);
-		if (do_cmd(host, suser, bp, &remin, &remout, argc) < 0) {
+		if (do_cmd(host, suser, bp, &remin, &remout) < 0) {
 			(void) xfree(bp);
 			++errs;
 			continue;

session.h

@@ -316,6 +316,7 @@ struct clientsession {
 
 	int lastauthtype; /* either AUTH_TYPE_PUBKEY or AUTH_TYPE_PASSWORD,
 						 for the last type of auth we tried */
+	int is_trivial_auth;
 	int ignore_next_auth_response;
 #if DROPBEAR_CLI_INTERACT_AUTH
 	int auth_interact_failed; /* flag whether interactive auth can still

signkey.c

@@ -28,6 +28,8 @@
 #include "buffer.h"
 #include "ssh.h"
 #include "ecdsa.h"
+#include "sk-ecdsa.h"
+#include "sk-ed25519.h"
 #include "rsa.h"
 #include "dss.h"
 #include "ed25519.h"
@@ -43,9 +45,15 @@ static const char * const signkey_names[DROPBEAR_SIGNKEY_NUM_NAMED] = {
 	"ecdsa-sha2-nistp256",
 	"ecdsa-sha2-nistp384",
 	"ecdsa-sha2-nistp521",
+#if DROPBEAR_SK_ECDSA
+	"sk-ecdsa-sha2-nistp256@openssh.com",
+#endif /* DROPBEAR_SK_ECDSA */
 #endif /* DROPBEAR_ECDSA */
 #if DROPBEAR_ED25519
 	"ssh-ed25519",
+#if DROPBEAR_SK_ED25519
+	"sk-ssh-ed25519@openssh.com",
+#endif /* DROPBEAR_SK_ED25519 */
 #endif /* DROPBEAR_ED25519 */
 	/* "rsa-sha2-256" is special-cased below since it is only a signature name, not key type */
 };
@@ -180,11 +188,17 @@ signkey_key_ptr(sign_key *key, enum signkey_type type) {
 	switch (type) {
 #if DROPBEAR_ED25519
 		case DROPBEAR_SIGNKEY_ED25519:
+#if DROPBEAR_SK_ED25519
+		case DROPBEAR_SIGNKEY_SK_ED25519:
+#endif
 			return (void**)&key->ed25519key;
 #endif
 #if DROPBEAR_ECDSA
 #if DROPBEAR_ECC_256
 		case DROPBEAR_SIGNKEY_ECDSA_NISTP256:
+#if DROPBEAR_SK_ECDSA
+		case DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256:
+#endif
 			return (void**)&key->ecckey256;
 #endif
 #if DROPBEAR_ECC_384
@@ -260,7 +274,11 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 	}
 #endif
 #if DROPBEAR_ECDSA
-	if (signkey_is_ecdsa(keytype)) {
+	if (signkey_is_ecdsa(keytype)
+#if DROPBEAR_SK_ECDSA
+		|| keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256
+#endif
+	) {
 		ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype);
 		if (eck) {
 			if (*eck) {
@@ -276,10 +294,14 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 	}
 #endif
 #if DROPBEAR_ED25519
-	if (keytype == DROPBEAR_SIGNKEY_ED25519) {
+	if (keytype == DROPBEAR_SIGNKEY_ED25519
+#if DROPBEAR_SK_ED25519
+		|| keytype == DROPBEAR_SIGNKEY_SK_ED25519
+#endif
+    ) {
 		ed25519_key_free(key->ed25519key);
 		key->ed25519key = m_malloc(sizeof(*key->ed25519key));
-		ret = buf_get_ed25519_pub_key(buf, key->ed25519key);
+		ret = buf_get_ed25519_pub_key(buf, key->ed25519key, keytype);
 		if (ret == DROPBEAR_FAILURE) {
 			m_free(key->ed25519key);
 			key->ed25519key = NULL;
@@ -287,6 +309,19 @@ int buf_get_pub_key(buffer *buf, sign_key *key, enum signkey_type *type) {
 	}
 #endif
 
+#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
+	if (0
+#if DROPBEAR_SK_ED25519
+		|| keytype == DROPBEAR_SIGNKEY_SK_ED25519
+#endif
+#if DROPBEAR_SK_ECDSA
+		|| keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256
+#endif
+	) {
+		key->sk_app = buf_getstring(buf, &key->sk_applen);
+	}
+#endif
+
 	TRACE2(("leave buf_get_pub_key"))
 
 	return ret;
@@ -401,7 +436,11 @@ void buf_put_pub_key(buffer* buf, sign_key *key, enum signkey_type type) {
 	}
 #endif
 #if DROPBEAR_ED25519
-	if (type == DROPBEAR_SIGNKEY_ED25519) {
+	if (type == DROPBEAR_SIGNKEY_ED25519
+#if DROPBEAR_SK_ED25519
+		|| type == DROPBEAR_SIGNKEY_SK_ED25519
+#endif
+	) {
 		buf_put_ed25519_pub_key(pubkeys, key->ed25519key);
 	}
 #endif
@@ -495,6 +534,7 @@ void sign_key_free(sign_key *key) {
 #endif
 
 	m_free(key->filename);
+	m_free(key->sk_app);
 
 	m_free(key);
 	TRACE2(("leave sign_key_free"))
@@ -568,7 +608,7 @@ static char * sign_key_sha1_fingerprint(const unsigned char* keyblob,
 	buflen = 7 + 3*SHA1_HASH_SIZE;
 	ret = (char*)m_malloc(buflen);
 
-	strcpy(ret, "sha1!! ");
+	strcpy(ret, "sha1 ");
 
 	for (i = 0; i < SHA1_HASH_SIZE; i++) {
 		unsigned int pos = 7 + 3*i;
@@ -639,6 +679,7 @@ void buf_put_sign(buffer* buf, sign_key *key, enum signature_type sigtype,
 }
 
 #if DROPBEAR_SIGNKEY_VERIFY
+
 /* Return DROPBEAR_SUCCESS or DROPBEAR_FAILURE.
  * If FAILURE is returned, the position of
  * buf is undefined. If SUCCESS is returned, buf will be positioned after the
@@ -652,6 +693,9 @@ int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype,
 
 	TRACE(("enter buf_verify"))
 
+	printhex("buf", buf->data, buf->pos);
+	printhex("remw", &buf->data[buf->pos], buf->len-buf->pos);
+
 	buf_getint(buf); /* blob length */
 	type_name = buf_getstring(buf, &type_name_len);
 	sigtype = signature_type_from_name(type_name, type_name_len);
@@ -695,6 +739,22 @@ int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype,
 		return buf_ed25519_verify(buf, key->ed25519key, data_buf);
 	}
 #endif
+#if DROPBEAR_SK_ECDSA
+	if (keytype == DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256) {
+		ecc_key **eck = (ecc_key**)signkey_key_ptr(key, keytype);
+		if (eck && *eck) {
+			return buf_sk_ecdsa_verify(buf, *eck, data_buf, key->sk_app, key->sk_applen);
+		}
+	}
+#endif
+#if DROPBEAR_SK_ED25519
+	if (keytype == DROPBEAR_SIGNKEY_SK_ED25519) {
+		dropbear_ed25519_key **eck = (dropbear_ed25519_key**)signkey_key_ptr(key, keytype);
+		if (eck && *eck) {
+			return buf_sk_ed25519_verify(buf, *eck, data_buf, key->sk_app, key->sk_applen);
+		}
+	}
+#endif
 
 	dropbear_exit("Non-matching signing type");
 	return DROPBEAR_FAILURE;

signkey.h

@@ -44,9 +44,15 @@ enum signkey_type {
 	DROPBEAR_SIGNKEY_ECDSA_NISTP256,
 	DROPBEAR_SIGNKEY_ECDSA_NISTP384,
 	DROPBEAR_SIGNKEY_ECDSA_NISTP521,
+#if DROPBEAR_SK_ECDSA
+	DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256,
+#endif /* DROPBEAR_SK_ECDSA */
 #endif /* DROPBEAR_ECDSA */
 #if DROPBEAR_ED25519
 	DROPBEAR_SIGNKEY_ED25519,
+#if DROPBEAR_SK_ED25519
+	DROPBEAR_SIGNKEY_SK_ED25519,
+#endif
 #endif
 	DROPBEAR_SIGNKEY_NUM_NAMED,
 	DROPBEAR_SIGNKEY_ECDSA_KEYGEN = 70, /* just "ecdsa" for keygen */
@@ -63,9 +69,15 @@ enum signature_type {
 	DROPBEAR_SIGNATURE_ECDSA_NISTP256 = DROPBEAR_SIGNKEY_ECDSA_NISTP256,
 	DROPBEAR_SIGNATURE_ECDSA_NISTP384 = DROPBEAR_SIGNKEY_ECDSA_NISTP384,
 	DROPBEAR_SIGNATURE_ECDSA_NISTP521 = DROPBEAR_SIGNKEY_ECDSA_NISTP521,
+#if DROPBEAR_SK_ECDSA
+	DROPBEAR_SIGNATURE_SK_ECDSA_NISTP256 = DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256,
+#endif /* DROPBEAR_SK_ECDSA */
 #endif /* DROPBEAR_ECDSA */
 #if DROPBEAR_ED25519
 	DROPBEAR_SIGNATURE_ED25519 = DROPBEAR_SIGNKEY_ED25519,
+#if DROPBEAR_SK_ED25519
+	DROPBEAR_SIGNATURE_SK_ED25519 = DROPBEAR_SIGNKEY_SK_ED25519,
+#endif
 #endif
 #if DROPBEAR_RSA_SHA1
 	DROPBEAR_SIGNATURE_RSA_SHA1 = 100, /* ssh-rsa signature (sha1) */
@@ -110,6 +122,12 @@ struct SIGN_key {
 #if DROPBEAR_ED25519
 	struct dropbear_ED25519_Key * ed25519key;
 #endif
+
+#if DROPBEAR_SK_ECDSA || DROPBEAR_SK_ED25519
+	/* application ID for U2F/FIDO key types, a malloced string */
+	char * sk_app;
+	unsigned int sk_applen;
+#endif
 };
 
 typedef struct SIGN_key sign_key;
@@ -130,6 +148,7 @@ void sign_key_free(sign_key *key);
 void buf_put_sign(buffer* buf, sign_key *key, enum signature_type sigtype, const buffer *data_buf);
 #if DROPBEAR_SIGNKEY_VERIFY
 int buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype, const buffer *data_buf);
+int sk_buf_verify(buffer * buf, sign_key *key, enum signature_type expect_sigtype, const buffer *data_buf, char* app, unsigned int applen);
 char * sign_key_fingerprint(const unsigned char* keyblob, unsigned int keybloblen);
 #endif
 int cmp_base64_key(const unsigned char* keyblob, unsigned int keybloblen, 

sk-ecdsa.c

@@ -0,0 +1,47 @@
+#include "includes.h"
+
+#if DROPBEAR_SK_ECDSA
+
+#include "dbutil.h"
+#include "ecc.h"
+#include "ecdsa.h"
+#include "sk-ecdsa.h"
+
+int buf_sk_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf, const char* app, unsigned int applen) {
+	hash_state hs;
+	unsigned char subhash[SHA256_HASH_SIZE];
+	buffer *sk_buffer = NULL, *sig_buffer = NULL;
+	unsigned char flags;
+	unsigned int counter;
+	int ret;
+
+	TRACE(("buf_sk_ecdsa_verify"))
+
+	/* from https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.u2f */
+	/* ecdsa signature to verify (r, s) */
+	sig_buffer = buf_getbuf(buf);
+
+	flags = buf_getbyte (buf);
+	counter = buf_getint (buf);
+	/* create the message to be signed */
+	sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);
+	sha256_init (&hs);
+	sha256_process (&hs, app, applen);
+	sha256_done (&hs, subhash);
+	buf_putbytes (sk_buffer, subhash, sizeof (subhash));
+	buf_putbyte (sk_buffer, flags);
+	buf_putint (sk_buffer, counter);
+	sha256_init (&hs);
+	sha256_process (&hs, data_buf->data, data_buf->len);
+	sha256_done (&hs, subhash);
+	buf_putbytes (sk_buffer, subhash, sizeof (subhash));
+
+	ret = buf_ecdsa_verify(sig_buffer, key, sk_buffer);
+	buf_free(sk_buffer);
+	buf_free(sig_buffer);
+
+	TRACE(("leave buf_sk_ecdsa_verify, ret=%d", ret))
+	return ret;
+}
+
+#endif /* DROPBEAR_SK_ECDSA */

sk-ecdsa.h

@@ -0,0 +1,15 @@
+#ifndef DROPBEAR_SK_ECDSA_H_
+#define DROPBEAR_SK_ECDSA_H_
+
+#include "includes.h"
+
+#if DROPBEAR_SK_ECDSA
+
+#include "buffer.h"
+#include "signkey.h"
+
+int buf_sk_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf, const char* app, unsigned int applen);
+
+#endif
+
+#endif /* DROPBEAR_SK_ECDSA_H_ */

sk-ed25519.c

@@ -0,0 +1,61 @@
+#include "includes.h"
+
+#if DROPBEAR_SK_ED25519
+
+#include "dbutil.h"
+#include "buffer.h"
+#include "curve25519.h"
+#include "ed25519.h"
+
+int buf_sk_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf, const char* app, unsigned int applen) {
+
+	int ret = DROPBEAR_FAILURE;
+	unsigned char *s;
+	unsigned long slen;
+	hash_state hs;
+	unsigned char hash[SHA256_HASH_SIZE];
+	buffer *sk_buffer = NULL;
+	unsigned char flags;
+	unsigned int counter;
+
+	TRACE(("enter buf_sk_ed25519_verify"))
+	dropbear_assert(key != NULL);
+
+	slen = buf_getint(buf);
+	if (slen != 64 || buf->len - buf->pos < slen) {
+		TRACE(("leave buf_sk_ed25519_verify: bad size"))
+		goto out;
+	}
+	s = buf_getptr(buf, slen);
+	buf_incrpos(buf, slen);
+
+	flags = buf_getbyte (buf);
+	counter = buf_getint (buf);
+	sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);
+	sha256_init (&hs);
+	sha256_process (&hs, app, applen);
+	sha256_done (&hs, hash);
+	buf_putbytes (sk_buffer, hash, sizeof (hash));
+	buf_putbyte (sk_buffer, flags);
+	buf_putint (sk_buffer, counter);
+	sha256_init (&hs);
+	sha256_process (&hs, data_buf->data, data_buf->len);
+	sha256_done (&hs, hash);
+	buf_putbytes (sk_buffer, hash, sizeof (hash));
+
+	if (dropbear_ed25519_verify(sk_buffer->data, sk_buffer->len,
+				    s, slen, key->pub) == 0) {
+		/* signature is valid */
+		TRACE(("leave buf_sk_ed25519_verify: success!"))
+		ret = DROPBEAR_SUCCESS;
+	}
+
+out:
+	if (sk_buffer) {
+		buf_free(sk_buffer);
+	}
+	TRACE(("leave buf_sk_ed25519_verify: ret %d", ret))
+	return ret;
+}
+
+#endif /* DROPBEAR_SK_ED25519 */

sk-ed25519.h

@@ -0,0 +1,15 @@
+#ifndef DROPBEAR_SK_ED25519_H_
+#define DROPBEAR_SK_ED25519_H_
+
+#include "includes.h"
+
+#if DROPBEAR_SK_ED25519
+
+#include "buffer.h"
+#include "ed25519.h"
+
+int buf_sk_ed25519_verify(buffer *buf, const dropbear_ed25519_key *key, const buffer *data_buf, const char* app, unsigned int applen);
+
+#endif
+
+#endif /* DROPBEAR_SK_ED25519_H_ */

svr-agentfwd.c

@@ -186,7 +186,6 @@ void svr_agentcleanup(struct ChanSess * chansess) {
 }
 
 static const struct ChanType chan_svr_agent = {
-	0, /* sepfds */
 	"auth-agent@openssh.com",
 	NULL,
 	NULL,

svr-auth.c

@@ -25,7 +25,6 @@
 /* This file (auth.c) handles authentication requests, passing it to the
  * particular type (auth-passwd, auth-pubkey). */
 
-#include <limits.h>
 
 #include "includes.h"
 #include "dbutil.h"

svr-authpubkeyoptions.c

@@ -166,6 +166,18 @@ int svr_add_pubkey_options(buffer *options_buf, int line_num, const char* filena
 			ses.authstate.pubkey_options->no_pty_flag = 1;
 			goto next_option;
 		}
+		if (match_option(options_buf, "restrict") == DROPBEAR_SUCCESS) {
+			dropbear_log(LOG_WARNING, "Restrict option set");
+			ses.authstate.pubkey_options->no_port_forwarding_flag = 1;
+#if DROPBEAR_SVR_AGENTFWD
+			ses.authstate.pubkey_options->no_agent_forwarding_flag = 1;
+#endif
+#if DROPBEAR_X11FWD
+			ses.authstate.pubkey_options->no_x11_forwarding_flag = 1;
+#endif
+			ses.authstate.pubkey_options->no_pty_flag = 1;
+			goto next_option;
+		}
 		if (match_option(options_buf, "command=\"") == DROPBEAR_SUCCESS) {
 			int escaped = 0;
 			const unsigned char* command_start = buf_getptr(options_buf, 0);

svr-chansession.c

@@ -54,7 +54,7 @@ static void closechansess(const struct Channel *channel);
 static void cleanupchansess(const struct Channel *channel);
 static int newchansess(struct Channel *channel);
 static void chansessionrequest(struct Channel *channel);
-static int sesscheckclose(const struct Channel *channel);
+static int sesscheckclose(struct Channel *channel);
 
 static void send_exitsignalstatus(const struct Channel *channel);
 static void send_msg_chansess_exitstatus(const struct Channel * channel,
@@ -64,7 +64,6 @@ static void send_msg_chansess_exitsignal(const struct Channel * channel,
 static void get_termmodes(const struct ChanSess *chansess);
 
 const struct ChanType svrchansess = {
-	0, /* sepfds */
 	"session", /* name */
 	newchansess, /* inithandler */
 	sesscheckclose, /* checkclosehandler */
@@ -76,12 +75,26 @@ const struct ChanType svrchansess = {
 /* required to clear environment */
 extern char** environ;
 
-static int sesscheckclose(const struct Channel *channel) {
+/* Returns whether the channel is ready to close. The child process
+   must not be running (has never started, or has exited) */
+static int sesscheckclose(struct Channel *channel) {
 	struct ChanSess *chansess = (struct ChanSess*)channel->typedata;
-	TRACE(("sesscheckclose, pid is %d", chansess->exit.exitpid))
-	return chansess->exit.exitpid != -1;
+	TRACE(("sesscheckclose, pid %d, exitpid %d", chansess->pid, chansess->exit.exitpid))
+
+	if (chansess->exit.exitpid != -1) {
+		channel->flushing = 1;
+	}
+	return chansess->pid == 0 || chansess->exit.exitpid != -1;
 }
 
+/* Handler for childs exiting, store the state for return to the client */
+
+/* There's a particular race we have to watch out for: if the forked child
+ * executes, exits, and this signal-handler is called, all before the parent
+ * gets to run, then the childpids[] array won't have the pid in it. Hence we
+ * use the svr_ses.lastexit struct to hold the exit, which is then compared by
+ * the parent when it runs. This work correctly at least in the case of a
+ * single shell spawned (ie the usual case) */
 void svr_chansess_checksignal(void) {
 	int status;
 	pid_t pid;
@@ -127,18 +140,9 @@ void svr_chansess_checksignal(void) {
 			/* we use this to determine how pid exited */
 			ex->exitsignal = -1;
 		}
-		
 	}
 }
 
-/* Handler for childs exiting, store the state for return to the client */
-
-/* There's a particular race we have to watch out for: if the forked child
- * executes, exits, and this signal-handler is called, all before the parent
- * gets to run, then the childpids[] array won't have the pid in it. Hence we
- * use the svr_ses.lastexit struct to hold the exit, which is then compared by
- * the parent when it runs. This work correctly at least in the case of a
- * single shell spawned (ie the usual case) */
 static void sesssigchild_handler(int UNUSED(dummy)) {
 	struct sigaction sa_chld;
 
@@ -423,35 +427,37 @@ out:
 
 /* Send a signal to a session's process as requested by the client*/
 static int sessionsignal(const struct ChanSess *chansess) {
+	TRACE(("sessionsignal"))
 
 	int sig = 0;
 	char* signame = NULL;
 	int i;
 
 	if (chansess->pid == 0) {
+		TRACE(("sessionsignal: done no pid"))
 		/* haven't got a process pid yet */
 		return DROPBEAR_FAILURE;
 	}
 
 	signame = buf_getstring(ses.payload, NULL);
 
-	i = 0;
-	while (signames[i].name != 0) {
+	for (i = 0; signames[i].name != NULL; i++) {
 		if (strcmp(signames[i].name, signame) == 0) {
 			sig = signames[i].signal;
 			break;
 		}
-		i++;
 	}
 
 	m_free(signame);
 
+	TRACE(("sessionsignal: pid %d signal %d", (int)chansess->pid, sig))
 	if (sig == 0) {
 		/* failed */
 		return DROPBEAR_FAILURE;
 	}
 			
 	if (kill(chansess->pid, sig) < 0) {
+		TRACE(("sessionsignal: kill() errored"))
 		return DROPBEAR_FAILURE;
 	} 
 
@@ -656,12 +662,13 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
 	unsigned int cmdlen = 0;
 	int ret;
 
-	TRACE(("enter sessioncommand"))
+	TRACE(("enter sessioncommand %d", channel->index))
 
-	if (chansess->cmd != NULL) {
+	if (chansess->pid != 0) {
 		/* Note that only one command can _succeed_. The client might try
 		 * one command (which fails), then try another. Ie fallback
 		 * from sftp to scp */
+		TRACE(("leave sessioncommand, already have a command"))
 		return DROPBEAR_FAILURE;
 	}
 
@@ -673,6 +680,7 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
 			if (cmdlen > MAX_CMD_LEN) {
 				m_free(chansess->cmd);
 				/* TODO - send error - too long ? */
+				TRACE(("leave sessioncommand, command too long %d", cmdlen))
 				return DROPBEAR_FAILURE;
 			}
 		}
@@ -685,6 +693,7 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
 #endif
 			{
 				m_free(chansess->cmd);
+				TRACE(("leave sessioncommand, unknown subsystem"))
 				return DROPBEAR_FAILURE;
 			}
 		}
@@ -741,6 +750,7 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
 	if (ret == DROPBEAR_FAILURE) {
 		m_free(chansess->cmd);
 	}
+	TRACE(("leave sessioncommand, ret %d", ret))
 	return ret;
 }
 
@@ -762,6 +772,7 @@ static int noptycommand(struct Channel *channel, struct ChanSess *chansess) {
 	ses.maxfd = MAX(ses.maxfd, channel->writefd);
 	ses.maxfd = MAX(ses.maxfd, channel->readfd);
 	ses.maxfd = MAX(ses.maxfd, channel->errfd);
+	channel->bidir_fd = 0;
 
 	addchildpid(chansess, chansess->pid);
 
@@ -830,20 +841,28 @@ static int ptycommand(struct Channel *channel, struct ChanSess *chansess) {
 		pty_make_controlling_tty(&chansess->slave, chansess->tty);
 		
 		if ((dup2(chansess->slave, STDIN_FILENO) < 0) ||
-			(dup2(chansess->slave, STDERR_FILENO) < 0) ||
 			(dup2(chansess->slave, STDOUT_FILENO) < 0)) {
 			TRACE(("leave ptycommand: error redirecting filedesc"))
 			return DROPBEAR_FAILURE;
 			}
 
-		close(chansess->slave);
-
 		/* write the utmp/wtmp login record - must be after changing the
-		 * terminal used for stdout with the dup2 above */
+		 * terminal used for stdout with the dup2 above, otherwise
+		 * the wtmp login will not be recorded */
 		li = chansess_login_alloc(chansess);
 		login_login(li);
+		dropbear_log(LOG_WARNING, "bad thing happened");
 		login_free_entry(li);
 
+		/* Can now dup2 stderr. Messages from login_login() have gone
+		to the parent stderr */
+		if (dup2(chansess->slave, STDERR_FILENO) < 0) {
+			TRACE(("leave ptycommand: error redirecting filedesc"))
+			return DROPBEAR_FAILURE;
+		}
+
+		close(chansess->slave);
+
 #if DO_MOTD
 		if (svr_opts.domotd && !chansess->cmd) {
 			/* don't show the motd if ~/.hushlogin exists */
@@ -888,6 +907,7 @@ static int ptycommand(struct Channel *channel, struct ChanSess *chansess) {
 		channel->readfd = chansess->master;
 		/* don't need to set stderr here */
 		ses.maxfd = MAX(ses.maxfd, chansess->master);
+		channel->bidir_fd = 1;
 
 		setnonblocking(chansess->master);
 
@@ -914,6 +934,7 @@ static void addchildpid(struct ChanSess *chansess, pid_t pid) {
 		svr_ses.childpidsize++;
 	}
 	
+	TRACE(("addchildpid %d pid %d for chansess %p", i, pid, chansess))
 	svr_ses.childpids[i].pid = pid;
 	svr_ses.childpids[i].chansess = chansess;
 
@@ -924,6 +945,11 @@ static void addchildpid(struct ChanSess *chansess, pid_t pid) {
 static void execchild(const void *user_data) {
 	const struct ChanSess *chansess = user_data;
 	char *usershell = NULL;
+	char *cp = NULL;
+	char *envcp = getenv("LANG");
+	if (envcp != NULL) {
+		cp = m_strdup(envcp);
+	}
 
 	/* with uClinux we'll have vfork()ed, so don't want to overwrite the
 	 * hostkey. can't think of a workaround to clear it */
@@ -936,19 +962,21 @@ static void execchild(const void *user_data) {
 	seedrandom();
 #endif
 
-	/* clear environment */
+	/* clear environment if -e was not set */
 	/* if we're debugging using valgrind etc, we need to keep the LD_PRELOAD
 	 * etc. This is hazardous, so should only be used for debugging. */
+	if ( !svr_opts.pass_on_env) {
 #ifndef DEBUG_VALGRIND
 #ifdef HAVE_CLEARENV
-	clearenv();
+		clearenv();
 #else /* don't HAVE_CLEARENV */
-	/* Yay for posix. */
-	if (environ) {
-		environ[0] = NULL;
-	}
+		/* Yay for posix. */
+		if (environ) {
+			environ[0] = NULL;
+		}
 #endif /* HAVE_CLEARENV */
 #endif /* DEBUG_VALGRIND */
+	}
 
 #if DROPBEAR_SVR_MULTIUSER
 	/* We can only change uid/gid as root ... */
@@ -982,6 +1010,10 @@ static void execchild(const void *user_data) {
 	addnewvar("HOME", ses.authstate.pw_dir);
 	addnewvar("SHELL", get_user_shell());
 	addnewvar("PATH", DEFAULT_PATH);
+	if (cp != NULL) {
+		addnewvar("LANG", cp);
+		m_free(cp);
+	}	
 	if (chansess->term != NULL) {
 		addnewvar("TERM", chansess->term);
 	}

svr-runopts.c

@@ -64,6 +64,7 @@ static void printhelp(const char * progname) {
 					"-R		Create hostkeys as required\n" 
 #endif
 					"-F		Don't fork into background\n"
+					"-e		Pass on server process environment to child process\n"
 #ifdef DISABLE_SYSLOG
 					"(Syslog support not compiled in, using stderr)\n"
 #else
@@ -99,7 +100,7 @@ static void printhelp(const char * progname) {
 #if INETD_MODE
 					"-i		Start for inetd\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, in seconds)\n"
 					"-I <idle_timeout>  (0 is never, default %d, in seconds)\n"
 #if DROPBEAR_PLUGIN
@@ -173,6 +174,7 @@ void svr_getopts(int argc, char ** argv) {
         svr_opts.pubkey_plugin = NULL;
         svr_opts.pubkey_plugin_options = NULL;
 #endif
+	svr_opts.pass_on_env = 0;
 
 #ifndef DISABLE_ZLIB
 	opts.compress_mode = DROPBEAR_COMPRESS_DELAYED;
@@ -223,6 +225,10 @@ void svr_getopts(int argc, char ** argv) {
 					opts.usingsyslog = 0;
 					break;
 #endif
+				case 'e':
+					svr_opts.pass_on_env = 1;
+					break;
+
 #if DROPBEAR_SVR_LOCALTCPFWD
 				case 'j':
 					svr_opts.nolocaltcp = 1;
@@ -379,12 +385,9 @@ void svr_getopts(int argc, char ** argv) {
 		}
 	}
 #endif
-	
+
 	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 (maxauthtries_arg) {
@@ -396,7 +399,7 @@ void svr_getopts(int argc, char ** argv) {
 		svr_opts.maxauthtries = val;
 	}
 
-	
+
 	if (keepalive_arg) {
 		unsigned int val;
 		if (m_str_to_uint(keepalive_arg, &val) == DROPBEAR_FAILURE) {
@@ -665,6 +668,12 @@ void load_all_hostkeys() {
 		any_keys = 1;
 	}
 #endif
+#if DROPBEAR_SK_ECDSA
+	disablekey(DROPBEAR_SIGNKEY_SK_ECDSA_NISTP256);
+#endif 
+#if DROPBEAR_SK_ED25519
+	disablekey(DROPBEAR_SIGNKEY_SK_ED25519);
+#endif
 
 	if (!any_keys) {
 		dropbear_exit("No hostkeys available. 'dropbear -R' may be useful or run dropbearkey.");

svr-session.c

@@ -195,8 +195,13 @@ void svr_session(int sock, int childpipe) {
 	/* start off with key exchange */
 	send_msg_kexinit();
 
-	/* Run the main for loop. NULL is for the dispatcher - only the client
-	 * code makes use of it */
+#if DROPBEAR_FUZZ
+    if (fuzz.fuzzing) {
+        fuzz_svr_hook_preloop();
+    }
+#endif
+
+	/* Run the main for-loop. */
 	session_loop(svr_chansess_checksignal);
 
 	/* Not reached */
@@ -209,6 +214,7 @@ void svr_dropbear_exit(int exitcode, const char* format, va_list param) {
 	char fullmsg[300];
 	char fromaddr[60];
 	int i;
+	int add_delay = 0;
 
 #if DROPBEAR_PLUGIN
         if ((ses.plugin_session != NULL)) {
@@ -241,13 +247,33 @@ void svr_dropbear_exit(int exitcode, const char* format, va_list param) {
 		snprintf(fullmsg, sizeof(fullmsg), 
 				"Exit before auth%s: (user '%s', %u fails): %s",
 				fromaddr, ses.authstate.pw_name, ses.authstate.failcount, exitmsg);
+		add_delay = 1;
 	} else {
 		/* before userauth */
 		snprintf(fullmsg, sizeof(fullmsg), "Exit before auth%s: %s", fromaddr, exitmsg);
+		add_delay = 1;
 	}
 
 	dropbear_log(LOG_INFO, "%s", fullmsg);
 
+	/* To make it harder for attackers, introduce a delay to keep an
+	 * unauthenticated session open a bit longer, thus blocking a connection
+	 * slot until after the delay. Without this, while there is a limit on
+	 * the amount of attempts an attacker can make at the same time
+	 * (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt
+	 * is still short and thus for each of the allowed parallel attempts
+	 * many attempts can be chained one after the other. The attempt rate is
+	 * then:
+	 *     "MAX_UNAUTH_PER_IP / <process time of one attempt>".
+	 * With the delay, this rate becomes:
+	 *     "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".
+	 */
+	if ((add_delay != 0) && (UNAUTH_CLOSE_DELAY > 0)) {
+		TRACE(("svr_dropbear_exit: start delay of %d seconds", UNAUTH_CLOSE_DELAY));
+		sleep(UNAUTH_CLOSE_DELAY);
+		TRACE(("svr_dropbear_exit: end delay of %d seconds", UNAUTH_CLOSE_DELAY));
+	}
+
 #if DROPBEAR_VFORK
 	/* For uclinux only the main server process should cleanup - we don't want
 	 * forked children doing that */

svr-tcpfwd.c

@@ -39,8 +39,15 @@
 
 /* This is better than SSH_MSG_UNIMPLEMENTED */
 void recv_msg_global_request_remotetcp() {
-		TRACE(("recv_msg_global_request_remotetcp: remote tcp forwarding not compiled in"))
+	unsigned int wantreply = 0;
+
+	TRACE(("recv_msg_global_request_remotetcp: remote tcp forwarding not compiled in"))
+
+	buf_eatstring(ses.payload);
+	wantreply = buf_getbool(ses.payload);
+	if (wantreply) {
 		send_msg_request_failure();
+	}
 }
 
 /* */
@@ -52,7 +59,6 @@ static int newtcpdirect(struct Channel * channel);
 
 #if DROPBEAR_SVR_REMOTETCPFWD
 static const struct ChanType svr_chan_tcpremote = {
-	1, /* sepfds */
 	"forwarded-tcpip",
 	tcp_prio_inithandler,
 	NULL,
@@ -139,7 +145,7 @@ static int svr_cancelremotetcp() {
 	TRACE(("enter cancelremotetcp"))
 
 	bindaddr = buf_getstring(ses.payload, &addrlen);
-	if (addrlen > MAX_IP_LEN) {
+	if (addrlen > MAX_HOST_LEN) {
 		TRACE(("addr len too long: %d", addrlen))
 		goto out;
 	}
@@ -174,7 +180,7 @@ static int svr_remotetcpreq(int *allocated_listen_port) {
 	TRACE(("enter remotetcpreq"))
 
 	request_addr = buf_getstring(ses.payload, &addrlen);
-	if (addrlen > MAX_IP_LEN) {
+	if (addrlen > MAX_HOST_LEN) {
 		TRACE(("addr len too long: %d", addrlen))
 		goto out;
 	}
@@ -234,7 +240,6 @@ out:
 #if DROPBEAR_SVR_LOCALTCPFWD
 
 const struct ChanType svr_chan_tcpdirect = {
-	1, /* sepfds */
 	"direct-tcpip",
 	newtcpdirect, /* init */
 	NULL, /* checkclose */
@@ -284,10 +289,10 @@ static int newtcpdirect(struct Channel * channel) {
 		goto out;
 	}
 
+	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
+
 	snprintf(portstring, sizeof(portstring), "%u", destport);
 	channel->conn_pending = connect_remote(desthost, portstring, channel_connect_done, channel, NULL, NULL);
-
-	channel->prio = DROPBEAR_CHANNEL_PRIO_UNKNOWABLE;
 	
 	err = SSH_OPEN_IN_PROGRESS;
 

svr-x11fwd.c

@@ -211,7 +211,6 @@ static int x11_inithandler(struct Channel *channel) {
 }
 
 static const struct ChanType chan_x11 = {
-	0, /* sepfds */
 	"x11",
 	x11_inithandler, /* inithandler */
 	NULL, /* checkclose */

sysoptions.h

@@ -50,7 +50,7 @@
 #define MIN_RSA_KEYLEN 1024
 #endif
 
-#define MAX_BANNER_SIZE 2000 /* this is 25*80 chars, any more is foolish */
+#define MAX_BANNER_SIZE 2050 /* this is 25*80 chars, any more is foolish */
 #define MAX_BANNER_LINES 20 /* How many lines the client will display */
 
 /* the number of NAME=VALUE pairs to malloc for environ, if we don't have
@@ -86,9 +86,16 @@
 /* Required for pubkey auth */
 #define DROPBEAR_SIGNKEY_VERIFY ((DROPBEAR_SVR_PUBKEY_AUTH) || (DROPBEAR_CLIENT))
 
+/* crypt(password) must take less time than the auth failure delay
+   (250ms set in svr-auth.c). On Linux the delay depends on
+   password length, 100 characters here was empirically derived.
+
+   If a longer password is allowed Dropbear cannot compensate
+   for the crypt time which will expose which usernames exist */
 #define DROPBEAR_MAX_PASSWORD_LEN 100
 
 #define SHA1_HASH_SIZE 20
+#define SHA256_HASH_SIZE 32
 #define MD5_HASH_SIZE 16
 #define MAX_HASH_SIZE 64 /* sha512 */
 
@@ -190,7 +197,7 @@ If you test it please contact the Dropbear author */
 
 #define RECV_WINDOWEXTEND (opts.recv_window / 3) /* We send a "window extend" every
 								RECV_WINDOWEXTEND bytes */
-#define MAX_RECV_WINDOW (1024*1024) /* 1 MB should be enough */
+#define MAX_RECV_WINDOW (10*1024*1024) /* 10 MB should be enough */
 
 #define MAX_CHANNELS 1000 /* simple mem restriction, includes each tcp/x11
 							connection, so can't be _too_ small */

test/Makefile.in

@@ -0,0 +1,19 @@
+srcdir=@srcdir@
+
+all: test
+
+test: venv/bin/pytest fakekey
+	./venv/bin/pytest --hostkey=fakekey --dbclient=../dbclient --dropbear=../dropbear $(srcdir)
+
+one: venv/bin/pytest fakekey
+	./venv/bin/pytest --hostkey=fakekey --dbclient=../dbclient --dropbear=../dropbear $(srcdir) -k exit
+
+fakekey:
+	../dropbearkey -t ecdsa -f $@
+
+venv/bin/pytest: $(srcdir)/requirements.txt
+	python3 -m venv init venv
+	./venv/bin/pip install --upgrade pip
+	./venv/bin/pip install -r $(srcdir)/requirements.txt
+
+.PHONY: test

test/conftest.py

@@ -0,0 +1,18 @@
+def pytest_addoption(parser):
+    parser.addoption("--port", type=str, help="default is 2244 local, 22 remote")
+    parser.addoption("--dbclient", type=str, default="../dbclient")
+    parser.addoption("--dropbear", type=str, default="../dropbear")
+    parser.addoption("--hostkey", type=str, help="required unless --remote")
+    parser.addoption("--remote", type=str, help="remote host")
+    parser.addoption("--user", type=str, help="optional username")
+
+def pytest_configure(config):
+    opt = config.option
+    if not opt.hostkey and not opt.remote:
+        raise Exception("--hostkey must be given")
+    if not opt.port:
+        if opt.remote:
+            opt.port = "22"
+        else:
+            opt.port = "2244"
+

test/requirements.txt

@@ -0,0 +1,8 @@
+attrs==21.2.0
+iniconfig==1.1.1
+packaging==21.0
+pluggy==1.0.0
+py==1.10.0
+pyparsing==2.4.7
+pytest==6.2.5
+toml==0.10.2

test/test_channels.py

@@ -0,0 +1,134 @@
+from test_dropbear import *
+import signal
+import queue
+import socket
+
+# Tests for various edge cases of SSH channels and connection service
+
+def test_exitcode(request, dropbear):
+	r = dbclient(request, "exit 44")
+	assert r.returncode == 44
+
+@pytest.mark.xfail(reason="Not yet implemented", strict=True)
+def test_signal(request, dropbear):
+	r = dbclient(request, "kill -FPE $$")
+	assert r.returncode == -signal.SIGFPE
+
+@pytest.mark.parametrize("size", [0, 1, 2, 100, 5000, 200_000])
+def test_roundtrip(request, dropbear, size):
+	dat = os.urandom(size)
+	r = dbclient(request, "cat", input=dat, capture_output=True)
+	r.check_returncode()
+	assert r.stdout == dat
+
+@pytest.mark.parametrize("size", [0, 1, 2, 100, 20001, 41234])
+def test_read_pty(request, dropbear, size):
+	# testcase for
+	# https://bugs.openwrt.org/index.php?do=details&task_id=1814
+	# https://github.com/mkj/dropbear/pull/85
+	# From Yousong Zhou
+	# Fixed Oct 2021
+	#
+	#$ ssh -t my.router cat /tmp/bigfile | wc
+	#Connection to my.router closed.
+	#  0       1   14335 <- should be 20001
+
+	# Write the file. No newlines etc which could confuse ptys
+	dat = random_alnum(size)
+	r = dbclient(request, "tmpf=`mktemp`; echo $tmpf; cat > $tmpf", input=dat, capture_output=True, text=True)
+	tmpf = r.stdout.rstrip()
+	r.check_returncode()
+	# Read with a pty, this is what is being tested.
+	# Timing/buffering is subtle, we seem to need to cat a file from disk to hit it.
+	m, s = pty.openpty()
+	r = dbclient(request, "-t", f"cat {tmpf}; rm {tmpf}", stdin=s, capture_output=True)
+	r.check_returncode()
+	assert r.stdout.decode() == dat
+
+@pytest.mark.parametrize("fd", [1, 2])
+def test_bg_sleep(request, fd, dropbear):
+	# https://lists.ucc.asn.au/pipermail/dropbear/2006q1/000362.html
+	# Rob Landley "Is this a bug?" 24 Mar 2006
+	# dbclient user@system "sleep 10& echo hello"
+	#
+	# It should return right after printing hello, but it doesn't.  It waits until
+	# the child process exits.
+
+	# failure is TimeoutExpired
+	redir = "" if fd == 1 else " >&2 "
+	r = dbclient(request, f"sleep 10& echo hello {redir}",
+		capture_output=True, timeout=2, text=True)
+	r.check_returncode()
+	st = r.stdout if fd == 1 else r.stderr
+
+	if fd == 2 and 'accepted unconditionally' in st:
+		# ignore hostkey warning, a bit of a hack
+		assert st.endswith("\n\nhello\n")
+	else:
+		assert st.rstrip() == "hello"
+
+
+def test_idle(request, dropbear):
+	# Idle test, -I 1 should make it return before the 2 second timeout
+	r = dbclient(request, "-I", "1", "echo zong; sleep 10",
+		capture_output=True, timeout=2, text=True)
+	r.check_returncode()
+	assert r.stdout.rstrip() == "zong"
+
+@pytest.mark.parametrize("size", [1, 4000, 40000])
+def test_netcat(request, dropbear, size):
+	opt = request.config.option
+	if opt.remote:
+		pytest.xfail("don't know netcat address for remote")
+
+	dat1 = os.urandom(size)
+	dat2 = os.urandom(size)
+	with HandleTcp(3344, 1, dat2) as tcp:
+		r = dbclient(request, "-B", "localhost:3344", input=dat1, capture_output=True)
+		r.check_returncode()
+		assert r.stdout == dat2
+		assert tcp.inbound() == dat1
+
+@pytest.mark.parametrize("size", [1, 4000, 40000])
+@pytest.mark.parametrize("fwd_flag", "LR")
+def test_tcpflushout(request, dropbear, size, fwd_flag):
+	""" Tests that an opened TCP connection prevent a SSH session from being closed
+	until that TCP connection has finished transferring
+	"""
+	opt = request.config.option
+	if opt.remote:
+		pytest.xfail("don't know address for remote")
+
+	dat1 = os.urandom(size)
+	dat2 = os.urandom(size)
+	q = queue.Queue()
+	with HandleTcp(3344, timeout=1, response=q) as tcp:
+
+		r = dbclient(request, f"-{fwd_flag}", "7788:localhost:3344", "sleep 0.1; echo -n done",
+			text=True, background=True, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL)
+		# time to let the listener start
+		time.sleep(0.1)
+		# open a tcp connection
+		c = socket.create_connection(("localhost", 7788))
+
+		# wait for the shell to finish. sleep a bit longer in case it exits.
+		assert r.stdout.read(4) == "done"
+		time.sleep(0.1)
+
+		# now the shell has finished, we can write on the tcp socket
+		c.sendall(dat2)
+		c.shutdown(socket.SHUT_WR)
+		q.put(dat1)
+
+		# return a tcp response
+		q.put(None)
+		# check hasn't exited
+		assert r.poll() == None
+
+		# read the response
+		assert readall_socket(c) == dat1
+		c.close()
+		assert tcp.inbound() == dat2
+		# check has exited, allow time for dbclient to exit
+		time.sleep(0.1)
+		assert r.poll() == 0

test/test_dropbear.py

@@ -0,0 +1,114 @@
+import subprocess
+import os
+import pty
+import tempfile
+import logging
+import time
+import socketserver
+import threading
+import queue
+
+import pytest
+
+LOCALADDR="127.0.5.5"
+
+@pytest.fixture(scope="module")
+def dropbear(request):
+	opt = request.config.option
+	if opt.remote:
+		yield None
+		return
+
+	args = [opt.dropbear,
+		"-p", LOCALADDR, # bind locally only
+		"-r", opt.hostkey,
+		"-p", opt.port,
+		"-F", "-E",
+		]
+	p = subprocess.Popen(args, stderr=subprocess.PIPE, text=True)
+	# Wait until it has started listening
+	for l in p.stderr:
+		if "Not backgrounding" in l:
+			break
+	# Check it's still running
+		assert p.poll() is None
+	# Ready
+	yield p
+	p.terminate()
+	print("Terminated dropbear. Flushing output:")
+	for l in p.stderr:
+		print(l.rstrip())
+	print("Done")
+
+def dbclient(request, *args, **kwargs):
+	opt = request.config.option
+	host = opt.remote or LOCALADDR
+	base_args = [opt.dbclient, "-y", host, "-p", opt.port]
+	if opt.user:
+		full_args.extend(['-l', opt.user])
+	full_args = base_args + list(args)
+	bg = kwargs.get("background")
+	if "background" in kwargs:
+		del kwargs["background"]
+	if bg:
+		return subprocess.Popen(full_args, **kwargs)
+	else:
+		kwargs.setdefault("timeout", 10)
+		# wait for response
+		return subprocess.run(full_args, **kwargs)
+
+class HandleTcp(socketserver.ThreadingMixIn, socketserver.TCPServer):
+	""" Listens for a single incoming request, sends a response if given,
+	and returns the inbound data.
+	Reponse can be a queue object, in which case each item in the queue will
+	be sent as a response, until it receives a None item.
+	"""
+	def __init__(self, port, timeout, response=None):
+		super().__init__(('localhost', port), self.Handler)
+		self.port = 	port
+		self.timeout = timeout
+		self.response = response
+		self.sink = None
+
+	class Handler(socketserver.StreamRequestHandler):
+		def handle(self):
+			if isinstance(self.server.response, queue.Queue):
+				while True:
+					i = self.server.response.get()
+					if i is None:
+						break
+					self.wfile.write(i)
+			elif self.server.response:
+				self.wfile.write(self.server.response)
+			assert self.server.sink is None, ">1 request sent to handler"
+			self.server.sink = self.rfile.read()
+
+	def __enter__(self):
+		self.server_thread = threading.Thread(target=self.serve_forever)
+		self.server_thread.daemon = True
+		self.server_thread.start()
+		return self
+
+	def __exit__(self, *exc_stuff):
+		self.shutdown()
+		self.server_thread.join()
+
+	def inbound(self):
+		""" Returns the data sent to the socket """
+		return self.sink
+
+def readall_socket(sock):
+	b = []
+	while True:
+		i = sock.recv(4096)
+		if not i:
+			break
+		b.append(i)
+	return b''.join(b)
+
+# returns a str
+def random_alnum(size):
+	r = os.urandom(500 + size*5)
+	return bytes(i for i in r if bytes((i,)).isalnum())[:size].decode()
+
+