Performing substitutions during post-patch breaks tools such as mkpatches,
making it very difficult to regenerate correct patches after making changes,
and often leading to substituted string replacements being committed.
Changes:
- Security: Fix double-free in server TCP listener cleanup
A double-free in the server could be triggered by an authenticated
user if dropbear is running with -a (Allow connections to forwarded
ports from any host)
This could potentially allow arbitrary code execution as root by an
authenticated user. Affects versions 2013.56 to 2016.74. Thanks to
Mark Shepard for reporting the crash.
CVE-2017-9078 https://secure.ucc.asn.au/hg/dropbear/rev/c8114a48837c
- Security: Fix information disclosure with ~/.ssh/authorized_keys
symlink. Dropbear parsed authorized_keys as root, even if it were
a symlink. The fix is to switch to user permissions when opening
authorized_keys
A user could symlink their ~/.ssh/authorized_keys to a root-owned
file they couldn't normally read. If they managed to get that file
to contain valid authorized_keys with command= options it might be
possible to read other contents of that file.
This information disclosure is to an already authenticated user.
Thanks to Jann Horn of Google Project Zero for reporting this.
CVE-2017-9079 https://secure.ucc.asn.au/hg/dropbear/rev/0d889b068123
- Generate hostkeys with dropbearkey atomically and flush to disk with
fsync. Thanks to Andrei Gherzan for a patch.
- Fix out of tree builds with bundled libtom
Thanks to Henrik Nordström and Peter Krefting for patches.
2016.74 - 21 July 2016
- Security: Message printout was vulnerable to format string injection.
If specific usernames including "%" symbols can be created on a system
(validated by getpwnam()) then an attacker could run arbitrary code as root
when connecting to Dropbear server.
A dbclient user who can control username or host arguments could potentially
run arbitrary code as the dbclient user. This could be a problem if scripts
or webpages pass untrusted input to the dbclient program.
CVE-2016-7406
https://secure.ucc.asn.au/hg/dropbear/rev/b66a483f3dcb
- Security: dropbearconvert import of OpenSSH keys could run arbitrary code as
the local dropbearconvert user when parsing malicious key files
CVE-2016-7407
https://secure.ucc.asn.au/hg/dropbear/rev/34e6127ef02e
- Security: dbclient could run arbitrary code as the local dbclient user if
particular -m or -c arguments are provided. This could be an issue where
dbclient is used in scripts.
CVE-2016-7408
https://secure.ucc.asn.au/hg/dropbear/rev/eed9376a4ad6
- Security: dbclient or dropbear server could expose process memory to the
running user if compiled with DEBUG_TRACE and running with -v
CVE-2016-7409
https://secure.ucc.asn.au/hg/dropbear/rev/6a14b1f6dc04
The security issues were reported by an anonymous researcher working with
Beyond Security's SecuriTeam Secure Disclosure www.beyondsecurity.com/ssd.html
- Fix port forwarding failure when connecting to domains that have both
IPv4 and IPv6 addresses. The bug was introduced in 2015.68
- Fix 100% CPU use while waiting for rekey to complete. Thanks to Zhang Hui P
for the patch
2016.73 - 18 March 2016
- Support syslog in dbclient, option -o usesyslog=yes. Patch from Konstantin Tokarev
- Kill a proxycommand when dbclient exits, patch from Konstantin Tokarev
- Option to exit when a TCP forward fails, patch from Konstantin Tokarev
- New "-o" option parsing from Konstantin Tokarev. This allows handling some extra options
in the style of OpenSSH, though implementing all OpenSSH options is not planned.
- Fix crash when fallback initshells() is used, reported by Michael Nowak and Mike Tzou
- Allow specifying commands eg "dropbearmulti dbclient ..." instead of symlinks
- Various cleanups for issues found by a lint tool, patch from Francois Perrad
- Fix tab indent consistency, patch from Francois Perrad
- Fix issues found by cppcheck, reported by Mike Tzou
- Use system memset_s() or explicit_bzero() if available to clear memory. Also make
libtomcrypt/libtommath routines use that (or Dropbear's own m_burn()).
- Prevent scp failing when the local user doesn't exist. Based on patch from Michael Witten.
- Improved Travis CI test running, thanks to Mike Tzou
- Improve some code that was flagged by Coverity and Fortify Static Code Analyzer
2016.72 - 9 March 2016
- Validate X11 forwarding input. Could allow bypass of authorized_keys command= restrictions,
found by github.com/tintinweb. Thanks for Damien Miller for a patch. CVE-2016-3116
https://secure.ucc.asn.au/hg/dropbear/rev/a3e8389e01ff
2015.71 - 3 December 2015
- Fix "bad buf_incrpos" when data is transferred, broke in 2015.69
- Fix crash on exit when -p address:port is used, broke in 2015.68, thanks to
Frank Stollenwerk for reporting and investigation
- Fix building with only ENABLE_CLI_REMOTETCPFWD given, patch from Konstantin Tokarev
- Fix bad configure script test which didn't work with dash shell, patch from Juergen Daubert,
broke in 2015.70
- Fix server race condition that could cause sessions to hang on exit,
https://github.com/robotframework/SSHLibrary/issues/128
2015.70 - 26 November 2015
- Fix server password authentication on Linux, broke in 2015.69
2015.69 - 25 November 2015
- Fix crash when forwarded TCP connections fail to connect (bug introduced in 2015.68)
- Avoid hang on session close when multiple sessions are started, affects Qt Creator
Patch from Andrzej Szombierski
- Reduce per-channel memory consumption in common case, increase default
channel limit from 100 to 1000 which should improve SOCKS forwarding for modern
webpages
- Handle multiple command line arguments in a single flag, thanks to Guilhem Moulin
- Manpage improvements from Guilhem Moulin
- Build fixes for Android from Mike Frysinger
- Don't display the MOTD when an explicit command is run from Guilhem Moulin
- Check curve25519 shared secret isn't zero
2015.68 - Saturday 8 August 2015
- Reduce local data copying for improved efficiency. Measured 30%
increase in throughput for connections to localhost
- Forwarded TCP ports connect asynchronously and try all available addresses
(IPv4, IPv6, round robin DNS)
- Fix all compile warnings, many patches from Gaël Portay
Note that configure with -Werror may not be successful on some platforms (OS X)
and some configuration options may still result in unused variable
warnings.
- Use TCP Fast Open on Linux if available. Saves a round trip at connection
to hosts that have previously been connected.
Needs a recent Linux kernel and possibly "sysctl -w net.ipv4.tcp_fastopen=3"
Client side is disabled by default pending further compatibility testing
with networks and systems.
- Increase maximum command length to 9000 bytes
- Free memory before exiting, patch from Thorsten Horstmann. Useful for
Dropbear ports to embedded systems and for checking memory leaks
with valgrind. Only partially implemented for dbclient.
This is disabled by default, enable with DROPBEAR_CLEANUP in sysoptions.h
- DROPBEAR_DEFAULT_CLI_AUTHKEY setting now always prepends home directory unless
there is a leading slash (~ isn't treated specially)
- Fix small ECC memory leaks
- Tighten validation of Diffie-Hellman parameters, from Florent Daigniere of
Matta Consulting. Odds of bad values are around 2**-512 -- improbable.
- Twofish-ctr cipher is supported though disabled by default
- Fix pre-authentication timeout when waiting for client SSH-2.0 banner, thanks
to CL Ouyang
- Fix null pointer crash with restrictions in authorized_keys without a command, patch from
Guilhem Moulin
- Ensure authentication timeout is handled while reading the initial banner,
thanks to CL Ouyang for finding it.
- Fix null pointer crash when handling bad ECC keys. Found by afl-fuzz
2015.67 - Wednesday 28 January 2015
- Call fsync() after generating private keys to ensure they aren't lost if a
reboot occurs. Thanks to Peter Korsgaard
- Disable non-delayed zlib compression by default on the server. Can be
enabled if required for old clients with DROPBEAR_SERVER_DELAY_ZLIB
- Default client key path ~/.ssh/id_dropbear
- Prefer stronger algorithms by default, from Fedor Brunner.
AES256 over 3DES
Diffie-hellman group14 over group1
- Add option to disable CBC ciphers.
- Disable twofish in default options.h
- Enable sha2 HMAC algorithms by default, the code was already required
for ECC key exchange. sha1 is the first preference still for performance.
- Fix installing dropbear.8 in a separate build directory, from Like Ma
- Allow configure to succeed if libtomcrypt/libtommath are missing, from Elan Ruusamäe
- Don't crash if ssh-agent provides an unknown type of key. From Catalin Patulea
- Minor bug fixes, a few issues found by Coverity scan
2014.66 - Thursday 23 October 2014
- Use the same keepalive handling behaviour as OpenSSH. This will work better
with some SSH implementations that have different behaviour with unknown
message types.
- Don't reply with SSH_MSG_UNIMPLEMENTED when we receive a reply to our own
keepalive message
- Set $SSH_CLIENT to keep bash happy, patch from Ryan Cleere
- Fix wtmp which broke since 2013.62, patch from Whoopie
2014.65 - Friday 8 August 2014
- Fix 2014.64 regression, server session hang on exit with scp (and probably
others), thanks to NiLuJe for tracking it down
- Fix 2014.64 regression, clock_gettime() error handling which broke on older
Linux kernels, reported by NiLuJe
- Fix 2014.64 regression, writev() could occassionally fail with EAGAIN which
wasn't caught
- Avoid error message when trying to set QoS on proxycommand or multihop pipes
- Use /usr/bin/xauth, thanks to Mike Frysinger
- Don't exit the client if the local user entry can't be found, thanks to iquaba
2014.64 - Sunday 27 July 2014
- Fix compiling with ECDSA and DSS disabled
- Don't exit abruptly if too many outgoing packets are queued for writev(). Patch
thanks to Ronny Meeus
- The -K keepalive option now behaves more like OpenSSH's "ServerAliveInterval".
If no response is received after 3 keepalives then the session is terminated. This
will close connections faster than waiting for a TCP timeout.
- Rework TCP priority setting. New settings are
if (connecting || ptys || x11) tos = LOWDELAY
else if (tcp_forwards) tos = 0
else tos = BULK
Thanks to Catalin Patulea for the suggestion.
- Improve handling of many concurrent new TCP forwarded connections, should now
be able to handle as many as MAX_CHANNELS. Thanks to Eduardo Silva for reporting
and investigating it.
- Make sure that exit messages from the client are printed, regression in 2013.57
- Use monotonic clock where available, timeouts won't be affected by system time
changes
- Add -V for version
2014.63 - Wednesday 19 February 2014
- Fix ~. to terminate a client interactive session after waking a laptop
from sleep.
- Changed port separator syntax again, now using host^port. This is because
IPv6 link-local addresses use %. Reported by Gui Iribarren
- Avoid constantly relinking dropbearmulti target, fix "make install"
for multi target, thanks to Mike Frysinger
- Avoid getting stuck in a loop writing huge key files, reported by Bruno
Thomsen
- Don't link dropbearkey or dropbearconvert to libz or libutil,
thanks to Nicolas Boos
- Fix linking -lcrypt on systems without /usr/lib, thanks to Nicolas Boos
- Avoid crash on exit due to cleaned up keys before last packets are sent,
debugged by Ronald Wahl
- Fix a race condition in rekeying where Dropbear would exit if it received a
still-in-flight packet after initiating rekeying. Reported by Oliver Metz.
This is a longstanding bug but is triggered more easily since 2013.57
- Fix README for ecdsa keys, from Catalin Patulea
- Ensure that generated RSA keys are always exactly the length
requested. Previously Dropbear always generated N+16 or N+15 bit keys.
Thanks to Unit 193
- Fix DROPBEAR_CLI_IMMEDIATE_AUTH mode which saves a network round trip if the
first public key succeeds. Still not enabled by default, needs more
compatibility testing with other implementations.
- Fix for port 0 forwarding in the client and port forwarding with Apache MINA SSHD.
- Fix for bad system linux/pkt-sched.h header file with older Linux
kernels, from Steve Dover
- Fix signal handlers so that errno is saved, thanks to Erik Ahlén for a patch
and Mark Wickham for independently spotting the same problem.
Problems found locating distfiles:
Package f-prot-antivirus6-fs-bin: missing distfile fp-NetBSD.x86.32-fs-6.2.3.tar.gz
Package f-prot-antivirus6-ws-bin: missing distfile fp-NetBSD.x86.32-ws-6.2.3.tar.gz
Package libidea: missing distfile libidea-0.8.2b.tar.gz
Package openssh: missing distfile openssh-7.1p1-hpn-20150822.diff.bz2
Package uvscan: missing distfile vlp4510e.tar.Z
Otherwise, existing SHA1 digests verified and found to be the same on
the machine holding the existing distfiles (morden). All existing
SHA1 digests retained for now as an audit trail.
package build as a normal user
+ don't refer to MAKEFLAGS outside of pkgsrc/mk
+ add comments to patch files
+ use BSD_INSTALL_* definitions in the build Makefile
+ re-order some parts of the pkgsrc Makefile
+ use pkgsrc definitions for CFLAGS.${OPSYS} rather than conditionals
XXX - TO DO - fix the xauth issue here
also added a netbsd-specific build option
(changes)
2013.58 - Thursday 18 April 2013
- Fix building with Zlib disabled, thanks to Hans Harder and cuma@freetz
- Use % as a separator for ports, fixes scp in multihop mode, from Hans Harder
- Reject logins for other users when running as non-root, from Hans Harder
- Disable client immediate authentication request by default, it prevents
passwordless logins from working
2013.57 - Monday 15 April 2013
- Decreased connection setup time particularly with high latency connections,
the number of round trips has been reduced for both client and server.
CPU time hasn't been changed.
- Client will send an initial key exchange guess to save a round trip.
Dropbear implements an extension kexguess2@matt.ucc.asn.au to allow the first
packet guess to succeed in wider circumstances than the standard behaviour.
When communicating with other implementations the standard behaviour is used.
- Client side: when public key or password authentication with
$DROPBEAR_PASSWORD is used an initial authentication request will
be sent immediately rather than querying the list of available methods.
This behaviour is enabled by CLI_IMMEDIATE_AUTH option (on by default),
please let the Dropbear author know if it causes any interoperability
problems.
- Implement client escape characters ~. (terminate session) and
~^Z (background session)
- Server will more reliably clean up utmp when connection is closed, reported by
Mattias Walstr<C3><B6>m
- Don't crash if /dev/urandom isn't writable (RHEL5), thanks to Scott Case
- Add "-y -y" client option to skip host key checking, thanks to Hans Harder
- scp didn't work properly on systems using vfork(), thanks to Frank Van Uffelen
- Added IUTF8 terminal mode support (Linux and Mac OS). Not standardised yet
though probably will be soon
- Some verbose DROPBEAR_TRACE output is now hidden unless $DROPBEAR_TRACE2
enviroment variable is set
- Fix using asymmetric MAC algorithms (broke in )
- Renamed configure.in to configure.ac to quieten autoconf, from Mike Frysinger
2013.56 - Thursday 21 March 2013
- Allow specifying cipher (-c) and MAC (-m) lists for dbclient
- Allow using 'none' cipher or MAC (off by default, use options.h). Encryption
is used during authentication then disabled, similar to OpenSSH HPN mode
- Allow a user in immediately if the account has a blank password and blank
passwords are enabled
- Include a few extra sources of entropy from /proc on Linux, hash private keys
as well. Dropbear will also write gathered entropy back into /dev/urandom
- Added hmac-sha2-256 and hmac-sha2-512 support (off by default, use options.h)
- Don't sent bad address "localhost" for -R forward connections,
reported by Denis Bider
- Add "-B" runtime option to allow blank passwords
- Allow using IPv6 bracket notation for addresses in server "-p" option, from Ben Jencks
- A few improvements for Android from Reimar D<C3><B6>ffinger
- Fix memory leak for TCP forwarded connections to hosts that timed out,
reported by Norbert Bencz<C3><BA>r. Appears to be a very long-standing bug.
- Fix "make clean" for out of tree builds
- Fix compilation when ENABLE_{SVR,CLI}_AGENTFWD are unset
changes: fix a use-after-free bug which could be used to potentially
execute arbitrary code with root privileges, provided that the user
has been authenticated using a public key and also that a command
restriction is enforced (the "command" option must be used in
the authorized_keys file)
doesn't conflict with openssh.
Changes since 0.50:
0.52 - Wed 12 November 2008
- Add "netcat-alike" option (-B) to dbclient, allowing Dropbear to
tunnel standard input/output to a TCP port-forwarded remote host.
- Add "proxy command" support to dbclient, to allow using a spawned
process for IO rather than a direct TCP connection. eg
dbclient remotehost
is equivalent to
dbclient -J 'nc remotehost 22' remotehost
(the hostname is still provided purely for looking up saved host keys)
- Combine netcat-alike and proxy support to allow "multihop"
connections, with comma-separated host syntax. Allows running
dbclient user1@host1,user2@host2,user3@host3
to end up at host3 via the other two, using SSH TCP forwarding. It's
a bit like onion-routing. All connections are established from the
local machine. The comma-separated syntax can also be used for
scp/rsync, eg
rsync -a -e dbclient m@gateway,m2@host,martello:/home/matt/ ~/backup/
to bounce through a few hosts.
- Add -I "idle timeout" option (contributed by Farrell Aultman)
- Allow restrictions on authorized_keys logins such as restricting
commands to be run etc. This is a subset of those allowed by OpenSSH,
doesn't yet allow restricting source host.
- Use vfork() for scp on uClinux
- Default to PATH=/usr/bin:/bin for shells.
- Report errors if -R forwarding fails
- Add counter mode cipher support, which avoids some security problems
with the standard CBC mode.
- Support zlib@openssh.com delayed compression for client/server. It
can be required for the Dropbear server with the '-Z' option. This
is useful for security as it avoids exposing the server to attacks
on zlib by unauthenticated remote users, though requires client side
support.
- options.h has been split into options.h (user-changable) and
sysoptions.h (less commonly changed)
- Support "dbclient -s sftp" to specify a subsystem
- Fix a bug in replies to channel requests that could be triggered by
recent versions of PuTTY
0.51 - Thu 27 March 2008
- Make a copy of password fields rather erroneously relying on getwpnam()
to be safe to call multiple times
- If $SSH_ASKPASS_ALWAYS environment variable is set (and $SSH_ASKPASS is
as well) always use that program, ignoring isatty() and $DISPLAY
- Wait until a process exits before the server closes a connection, so
that an exit code can be sent. This fixes problems with exit codes not
being returned, which could cause scp to fail.
changes:
- Add DROPBEAR_PASSWORD environment variable to specify a dbclient password
- Use /dev/urandom by default, since that's what everyone does anyway
- Exit with an exit code of 1 if dropbear can't bind to any ports
- Improve network performance and add a -W <receive_window> argument for
adjusting the tradeoff between network performance and memory consumption
- Fix a problem where reply packets could be sent during key exchange,
in violation of the SSH spec. This could manifest itself with connections
being terminated after 8 hours with new TCP-forward connections being
established
- Add -K <keepalive_time> argument, ensuring that data is transmitted
over the connection at least every N seconds
- dropbearkey will no longer generate DSS keys of sizes other than 1024
bits, as required by the DSS specification. (Other sizes are still
accepted for use to provide backwards compatibility)
changes:
-a security fix which was already in pkgsrc (0.46nb1)
-bugfixes
-zlib compression for dbclient
-Set "low delay" TOS bit
-client keyboard-interactive mode support
-logging improvements
-Added aes-256 cipher and sha1-96 hmac
-allow connections to listening forwarded ports from remote machines
developer is officially maintaining the package.
The rationale for changing this from "tech-pkg" to "pkgsrc-users" is
that it implies that any user can try to maintain the package (by
submitting patches to the mailing list). Since the folks most likely
to care about the package are the folks that want to use it or are
already using it, this would leverage the energy of users who aren't
developers.
http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2005q4/000312.html
Noted by waldeck of hk2.uwaterloo.ca via pkgsrc-bugs.
Bump PKGREVISION.
Tested build on NetBSD and Linux. Tested dropbear server on NetBSD.
(This is during a freeze. Other stuff to be done later:
update to latest version. Install man pages. Mention "client" in
COMMENT and DESCR. Use CONF_FILES and sysconfdir. And maybe install the
"scp" tool also.)
changes:
- Makefile no longer appends 'static' to statically linked binaries
- Add optional SSH_ASKPASS support to the client
- Respect HOST_LOOKUP option
- Fix accidentally removed "return;" statement which was removed in 0.44
(causing clients which sent an empty terminal-modes string to fail to
connect - including pssh, ssh.com, danger hiptop). (patches
independently from Paul Fox, David Horwitt and Sven-Ola Tuecke)
- Read "y/n" response for fingerprints from /dev/tty directly so that dbclient
will work with scp.
changes:
-IPv6 support
-client added
-bugfixes
XXX dropbear wants to use /dev/random per default now which makes it
unusable on systems w/o entropy source. I've patched it back to
/dev/urandom. There might be security concerns.
in the process. (More information on tech-pkg.)
Bump PKGREVISION and BUILDLINK_DEPENDS of all packages using libtool and
installing .la files.
Bump PKGREVISION (only) of all packages depending directly on the above
via a buildlink3 include.
- SECURITY: Don't try to free() uninitialised variables in DSS verification
code. Thanks to Arne Bernin for pointing out this bug. This is possibly
exploitable, all users with DSS and pubkey-auth compiled in are advised to
upgrade.
- Clean up agent forwarding socket files correctly, patch from Gerrit Pape.
- Don't go into an infinite loop when portforwarding to servers which don't
send any initial data/banner. Patch from Nikola Vladov
- Fix for network vs. host byte order in logging remote TCP ports, also
from Gerrit Pape.
- Initialise many pointers to NULL, for general safety. Also checked cleanup
code for mp_ints (related to security issues above).
Changes:
0.38 - Sat Oct 11 2003 16:28:13 +0800
o Default hostkey path changed to /etc/dropbear/dropbear_{rsa,dss}_host_key
rather than /etc/dropbear_{rsa,dss}_host_key
o Added SMALL and MULTI text files which have info on compiling for multiple
binaries or small binaries
o Allow for commandline definition of some options.h settings
(without warnings)
o Be more careful handling EINTR
o More fixes for channel closing
o Added multi-binary support
o Improved logging of IPs, now get logged in all cases
o Don't chew cpu when waiting for version identification string, also
make sure that we kick off people if they don't auth within 5 minutes.
o Various small fixes, warnings etc
o sftp support works (relies on OpenSSH sftp binary or similar)
o Added --disable-shadow option (requested by the floppyfw guys)
0.37 - Wed Sept 24 2003 19:42:12 +0800
o Various portability fixes, fixes for Solaris 9, Tru64 5.1, Mac OS X 10.2,
AIX, BSDs
o Updated LibTomMath to 0.27 and LibTomCrypt to 0.90
o Renamed util.{c,h} to dbutil.{c,h} to avoid conflicts with system util.h
o Added some small changes so it'll work with AIX (plus Linux Affinity).
Thanks to Shig for them.
More bugfixes, etc.
The search for a small Secure Shell server to fit on a laptop with 4
megs ram and no hard disk was fruitless, so Matt Johnston decided to
write his own, and Dropbear is the result. It implements various
features of the SSH 2 protocol, including X11 and Authentication Agent
forwarding. Dropbear is Open Source software, distributed under a
MIT-style license.
Features
* A small memory footprint - Dropbear can compile to a 110kB
statically linked binary with uClibc (and only minimal options
selected).
* Implements X11 forwarding, and authentication-agent forwarding
for OpenSSH clients
* Compatible with OpenSSH ~/.ssh/authorized_keys public key
authentication
* Features can easily be disabled when compiling to save space.
* Preliminary TCP forwarding support (-L style only)
