Fixes:
- CVE-2017-9078: 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-2017-9079: 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.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
We want to use SPDX identifier for license string as much as possible.
SPDX short identifier for BSD-2c is BSD-2-Clause.
This change is done using following command.
find . -name "*.mk" | xargs sed -ri '/LICENSE( )?[\+:]?=/s/BSD-2c/BSD-2-Clause/g'
Signed-off-by: Rahul Bedarkar <rahulbedarkar89@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
According to https://matt.ucc.asn.au/dropbear/CHANGES there were some
severe security issues fixed.
Signed-off-by: Alexander Dahl <post@lespocky.de>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
some new runtime options, minor fixes, and fixes for issues found by
various code analyze and lintian tools.
Signed-off-by: Alexander Dahl <post@lespocky.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2016.72 - 9 March 2016
- Validate X11 forwarding input. Could allow bypass of authorized_keys command= restrictions,
found by github.com/tintinweb. Thanks to Damien Miller for a patch.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Commit e7d04dd2d replaced /etc/dropbear with a symlink to /var/run and
updated the start scripts to replace it with a real directory, so the
keys would be persistent. However, it turns out that this is pretty
confusing even for expert users, who don't know how to make the keys
really persistent now.
Update the help text explaining what the issue is, and telling the user
to replace the /etc/dropbear symlink with a symlink to a persistent
directory. Also mention the possiblity of unionfs.
Cc: Thomas De Schampheleire <patrickdepinguin@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Fixes a port-forwarding regression in 2015.68
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
'echo -n' is not a POSIX construct (no flag support), we shoud use
'printf', especially in init script.
This patch was generated by the following command line:
git grep -l 'echo -n' -- `git ls-files | grep -v 'patch'` | xargs sed -i 's/echo -n/printf/'
Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
When the rootfs is read-only, keys will be generated in a volatile
location, which is inherently bad as host keys will change on each boot,
rendering them virtually useless.
Add a warning so the user is at least aware of the issue.
Hide the rm output to avoid noisy output, now that we have a proper warning.
Move the starting message after the symlink-block, to avoid messages
collision. Move the umask as well, since /etc/dropbear/ may be world
readable; just the private host keys should be ?00 (and dropbear handles
that by itself).
[Peter: minor tweaks to commit message]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Peter Korsgaard <jacmet@uclibc.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Busybox "readlink -f" does not canonicalise paths when the target is
missing, while coreutils do.
Fix that by:
- making an absolute symlink
- dropping "-f" when calling readlink
Fixes#8276.
Reported-by: Jason Tang <tang@jtang.org>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Tested-by: Jason Tang <tang@jtang.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
This commit ensures that the /etc/dropbear symlink won't be removed if
it points elsewhere than /var/run/dropbear.
[Thomas:
- fix indentation / too long lines as suggested by Yann E. Morin.]
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
dropbear generates its keys at the first connection, and wants to save
them in /etc/dropbear (not configurable).
Currently, our /etc/dropbear is a directory.
When the filesystem is read-only, dropbear can't save its keys, so
refuses all connections.
Fix that with:
- at build time, create /etc/dropbear as a symlink to
/var/run/dropbear
- at runtime, if the filesystem is RW (we can rm /etc/dropbear),
we replace the symlink with an actual directory; otherwise,
when the filesystem is RO (we can't rm /etc/dropbear), we create
/var/run/dropbear so the symlink points to an existing directory
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Arnout Vandecappelle <arnout@mind.be>
Cc: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Acked-by: "Maxime Hadjinlian" <maxime.hadjinlian@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
The place for package-provided systemd units is /lib/systemd/system.
/etc/systemd/system is for custom units.
Reviewed-by: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
v2: only offer option to disable building SSH client.
do not offer options to disable password authentication and TCP forwarding.
Signed-off-by: Floris Bos <bos@je-eigen-domein.nl>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Switch sed options around since defaults have changed.
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Since a while, the semantic of BR2_PREFER_STATIC_LIB has been changed
from "prefer static libraries when possible" to "use only static
libraries". The former semantic didn't make much sense, since the user
had absolutely no control/idea of which package would use static
libraries, and which packages would not. Therefore, for quite some
time, we have been starting to enforce that BR2_PREFER_STATIC_LIB
should really build everything with static libraries.
As a consequence, this patch renames BR2_PREFER_STATIC_LIB to
BR2_STATIC_LIBS, and adjust the Config.in option accordingly.
This also helps preparing the addition of other options to select
shared, shared+static or just static.
Note that we have verified that this commit can be reproduced by
simply doing a global rename of BR2_PREFER_STATIC_LIB to
BR2_STATIC_LIBS plus adding BR2_PREFER_STATIC_LIB to Config.in.legacy.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
test a == b is not available in e.g. dash.
Command(s) used for editing:
q=\[\"\'\]
operand="${q}?[$]?[a-zA-Z0-9_\?]+${q}?" ## doesn't detect ${VAR}
test_expr="(\[\s+${operand}\s+)==(\s+${operand}\s+\])"
find . -type f -name '[SK][0-9][0-9]*' | \
xargs sed -r -e "s@${test_expr}@\1=\2@g" -i
Signed-off-by: André Erdmann <dywi@mailerd.de>
Acked-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
To be consistent with the recent change of FOO_MAKE_OPT into FOO_MAKE_OPTS,
make the same change for FOO_CONF_OPT.
Sed command used:
find * -type f | xargs sed -i 's#_CONF_OPT\>#&S#g'
Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Fixes some regressions introduced by 2014.64
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
The current SysV startup script create a directory which is necessary
for dropbear to correctly work.
This creation is not done with systemd.
Instead of both init creating the directory, we add the creation of this
directory to the INSTALL_TARGET_CMDS to make sure it's present.
[Peter: use make syntax for TARGET_DIR as pointed out by Thomas]
Signed-off-by: Maxime Hadjinlian <maxime.hadjinlian@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Fixes a number of issues. From the changelog:
- Avoid getting stuck in a loop writing huge key files, reported by Bruno
Thomsen
- 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
- 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 signal handlers so that errno is saved, thanks to Erik Ahlén for a patch
and Mark Wickham for independently spotting the same problem.
And at the same time get rid of the TIMEVAL_TO_TIMESPEC as dropbear provides a
fallback implementation if not available (and has done so since 2006).
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
The default port 22 used by dropbear for its SSH connections is not always
desired. Dropbear accepts an option '-p' to set the port, but doing this was
not possible from the buildroot-provided init script.
One way to fix this is by adding a custom S50dropbear in a project-specific
rootfs overlay. However, this approach has the big disadvantage that bug
fixes or improvements in the default init script (i.e. in newer buildroot
releases) are not available (unless you manually port these changes each
time you upgrade buildroot).
Another solution is to modify the default init script from a
project-specific post-build script. However, this is fragile because you'd
have to sed some line but this line may change in later buildroot releases.
Yet another solution is to change the default port at build time, by
patching the options.h header file in the dropbear sources. This was
proposed with a patch [1] before, but not accepted.
This patch implements another solution, hinted from the discussion in [1]:
the default init script now sources a config file /etc/default/dropbear, in
which the user can set the variable DROPBEAR_ARGS. This is similar to the
S81named init script in the bind package. The config file would be added to
a project-specific rootfs overlay, a custom skeleton, or created from a
post-build script.
This approach has the advantage of being simple and non-intrusive, without
any code duplication or fragile script modifications.
[1] http://lists.busybox.net/pipermail/buildroot/2013-November/083165.html
Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Bump to version 2013.62 with ECC support.
Switch the initscript to on-demand key generation and add systemd unit
file.
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Fixes two security issues:
- The Dropbear server could be made to consume large amounts
of memory because decompressed packet sizes weren't checked.
Depending on the OS and hardware this might be a denial of
service.
- Valid users could be identified due to timing variations.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Enclose all dropbear sub-options into a 'if BR2_PACKAGE_DROPBEAR'
... 'endif' block rather than having 'depends on BR2_PACKAGE_DROPBEAR'
for each option.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Switch ECHOs to SEDs to avoid issues with defines changing after
sysoptions.h was included - and it's cleaner.
Enable hmac-sha2-256 and hmac-sha2-512 support for the full featured.
Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
From the release notes:
Security: Fix use-after-free bug that could be triggered if command="..."
authorized_keys restrictions are used. Could allow arbitrary code
execution or bypass of the command="..." restriction to an authenticated
user.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Buildroot does not have wtmp or lastlog support by default so allow dropbear
to be configured to stop using them and hence to stop generating system log
error messages.
[Peter: invert to positive options, and disable by default]
Signed-off-by: Will Moore <will.moore@beraninstruments.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Thanks to the pkgparentdir and pkgname functions, we can rewrite the
AUTOTARGETS macro in a way that avoids the need for each package to
repeat its name and the directory in which it is present.
[Peter: pkgdir->pkgparentdir]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
