Since re-exec change in 2022.82 Dropbear count
treat authenticated sessions towards the unauthenticated
session limit. This is fixed by passing the childpipe FD
through to the re-execed process.
Why:
Running dropbear as a user (rootless) is aided if
files and programs can be saved/removed without
needing sudo.
What:
Use the same convention as DROPBEAR_DEFAULT_CLI_AUTHKEY;
if not starting with '/', then is relative to hedge's /home/hedge:
*_PRIV_FILENAME
DROPBEAR_PIDFILE
SFTPSERVER_PATH
default_options.h commentary added.
Changes kept to a minimum, so log entry in svr_kex.c#163
is refactored.
From:
Generated hostkey is <path> ... <finger-print>
to:
Generated hostkey path is <path>
Generated hostkey fingerprint is <fp>
Otherwise the unexpanded path was reported.
Patch modified by Matt Johnston
Signed-off-by: Begley Brothers Inc <begleybrothers@gmail.com>
This reverts git commit f972813ecd.
The sk algorithms need to remain in the sigalgs list so that they
are included in the server-sig-algs ext-info message sent by
the server. RFC8308 for server-sig-algs requires that all algorithms are
listed (though OpenSSH client 8.4p1 tested doesn't require that)
This allows ASLR to re-randomize the address
space for every connection, preventing some
vulnerabilities from being exploitable by
repeated probing.
Overhead (memory and time) is yet to be confirmed.
At present this is only enabled on Linux. Other BSD platforms
with fexecve() would probably also work though have not been tested.
* Implement server-side support for sk-ecdsa U2F-backed keys
* Fix out-of-bounds read on normal ecdsa-sha2-[identifier] keys
* Fix one more potential out-of-bounds read
* Check if nistp256 curve is used in sk-ecdsa-sha2- key
It's the only allowed curve per PROTOCOL.u2f specification
* Implement server-side support for sk-ed25519 FIDO2-backed keys
* Keys with type sk-* make no sense as host keys, so they should be
disabled
* fix typo
* Make sk-ecdsa call buf_ecdsa_verify
This reduces code duplication, the SK code just handles the
different message format.
* 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
* Remove debugging output, which causes compilation errors with DEBUG_TRACE disabled
* Proper cleanup of sk_app
Co-authored-by: Matt Johnston <matt@codeconstruct.com.au>
* Add support for Ed25519 as a public key type
Ed25519 is a elliptic curve signature scheme that offers
better security than ECDSA and DSA and good performance. It may be
used for both user and host keys.
OpenSSH key import and fuzzer are not supported yet.
Initially inspired by Peter Szabo.
* Add curve25519 and ed25519 fuzzers
* Add import and export of Ed25519 keys
* Implemented dynamic loading of an external plug-in shared library to delegate public key authentication
* Moved conditional compilation of the plugin infrastructure into the configure.ac script to be able to add -ldl to dropbear build only when the flag is enabled
* Added tags file to the ignore list
* Updated API to have the constructor to return function pointers in the pliugin instance. Added support for passing user name to the checkpubkey function. Added options to the session returned by the plugin and have dropbear to parse and process them
* Added -rdynamic to the linker flags when EPKA is enabled
* Changed the API to pass a previously created session to the checkPubKey function (created during preauth)
* Added documentation to the API
* Added parameter addrstring to plugin creation function
* Modified the API to retrieve the auth options. Instead of having them as field of the EPKASession struct, they are stored internally (plugin-dependent) in the plugin/session and retrieved through a pointer to a function (in the session)
* Changed option string to be a simple char * instead of unsigned char *
For the sake of review, this commit alters only the code; the affiliated
comments within the source files also need to be updated, but doing so
now would obscure the operational changes that have been made here.
* All on/off options have been switched to the numeric `#if' variant;
that is the only way to make this `default_options.h.in' thing work
in a reasonable manner.
* There is now some very minor compile-time checking of the user's
choice of options.
* NO_FAST_EXPTMOD doesn't seem to be used, so it has been removed.
* ENABLE_USER_ALGO_LIST was supposed to be renamed DROPBEAR_USER_ALGO_LIST,
and this commit completes that work.
* DROPBEAR_FUZZ seems to be a relatively new, as-yet undocumented option,
which was added by the following commit:
commit 6e0b539e9c
Author: Matt Johnston <matt@ucc.asn.au>
Date: Tue May 23 22:29:21 2017 +0800
split out checkpubkey_line() separately
It has now been added to `sysoptions.h' and defined as `0' by default.
* The configuration option `DROPBEAR_PASSWORD_ENV' is no longer listed in
`default_options.h.in'; it is no longer meant to be set by the user, and
is instead left to be defined in `sysoptions.h' (where it was already being
defined) as merely the name of the environment variable in question:
DROPBEAR_PASSWORD
To enable or disable use of that environment variable, the user must now
toggle `DROPBEAR_USE_DROPBEAR_PASSWORD'.
* The sFTP support is now toggled by setting `DROPBEAR_SFTPSERVER', and the
path of the sFTP server program is set independently through the usual
SFTPSERVER_PATH.
Add support for '-T n' for a run-time specification for maximum number
of authentication attempts where 'n' is between 1 and compile time
option MAX_AUTH_TRIES.
A default number of tries can be specified at compile time using
'DEFAULT_AUTH_TRIES' which itself defaults to MAX_AUTH_TRIES for
backwards compatibility.
Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
This change adds a -c option to dropbear, to force the session to use a
specific command, in a similar fashion to OpenSSH's ForceCommand
configuration option.
This is useful to provide a simple fixed service over ssh, without
requiring an authorized key file for the per-key forced_command option.
This setting takes precedence over the channel session's provided
command, and the per-key forced_command setting.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
