CVE description :
The recv_msg_userauth_request function in svr-auth.c in Dropbear through
2018.76 is prone to a user enumeration vulnerability because username
validity affects how fields in SSH_MSG_USERAUTH messages are handled,
a similar issue to CVE-2018-15473 in an unrelated codebase.
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
Override the default shutdown action (stop) and close all processes
of dropbear
Since commit 498fe85, the stop action only closes the process
that's listening for new connections, maintaining the ones with
existing clients.
This poses a problem when restarting or shutting-down a device,
because the connections with existing SSH clients, like OpenSSH,
are not properly closed, causing them to hang.
This situation can be avoided by closing all dropbear processes when
shutting-down the system, which closes properly the connections with
current clients.
Signed-off-by: Christian Schoenebeck <christian.schoenebeck@gmail.com>
[Luis: Rework commit message]
Signed-off-by: Luis Araneda <luaraneda@gmail.com>
The default receive window size in dropbear is hardcoded to 24576 byte
to limit memory usage. This value was chosen for 100Mbps networks, and
limits the throughput of scp on faster networks. It also severely limits
scp throughput on high-latency links.
Add an option to set the receive window size so that people can improve
performance without having to recompile dropbear.
Setting the window size to the highest value supported by dropbear
improves throughput from my build machine to an APU2 on the same LAN
from 7MB/s to 7.9MB/s, and to an APU2 over a link with ~65ms latency
from 320KB/s to 7.5MB/s.
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
As MD5 is known weak for many years and more and more
penetration test tools complain about enabled MD5 HMAC
I think it's time to drop it.
By disabling the MD5 HMAC support dropbear will also
automatically use SHA1 for fingerprints.
This shouldn't be a problem too.
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
CPE ids helps to tracks CVE in packages.
https://cpe.mitre.org/specification/
Thanks to swalker for CPE to package mapping and
keep tracking CVEs.
Acked-by: Jo-Philipp Wich <jo@mein.io>
Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Adds config option to enable compression support which is usefull
when using a terminal sessions over a slow link. Impact on binary
size is negligible but additional 60 kB (uncompressed) is needed for
a shared zlib library.
Signed-off-by: Marcin Jurkowski <marcin1j@gmail.com>
ssh and scp commands interfere with OpenSSH when installed in /usr/bin .
One use case is when installing dropbear to get root access when only OpenSSH is available (OpenSSH disallows root password logins). Once dropbear installs, it replaces OpenSSH's executables, even when removed with opkg. OpenSSH must be reinstalled to get them back.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Add a uci option to set the new max auth tries paramater in dropbear.
Set the default to 3, as 10 seems excessive.
Signed-off-by: Stijn Tintel <stijn@linux-ipv6.be>
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>
- 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
Refresh patches, rework 100-pubkey_path.patch to work with new
authorized_keys validation.
Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
Install procd interface triggers only for interfaces which are enabled
so dropbear instances running on (an) enabled interface(s) are not
restarted due to an interface trigger of an interface which is disabled.
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
The only HMACs currently available use MD5 and SHA1, both of which have known
weaknesses. We already compile in the SHA256 code since we use Curve25519
by default, so there's no significant size penalty to enabling this.
Signed-off-by: Joseph C. Sible <josephcsible@users.noreply.github.com>
Harmonise handling of DEFAULT_PATH by removing the patch introducing #ifndef
guards around the path, and only using one means to set the path in the
makefile.
Signed-off-by: Dario Ernst <Dario.Ernst@riverbed.com>
Configurations without shadow passwords have been broken since the removal
of telnet: as the default entry in /etc/passwd is not empty (but rather
unset), there will be no way to log onto such a system by default. As
disabling shadow passwords is not useful anyways, remove this configuration
option.
The config symbol is kept (for a while), as packages from feeds depend on
it.
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
As security precaution and to limit the attack surface based on
the version reported by tools like nmap mask out the dropbear
version so the version is not visible anymore by snooping on the
wire. Version is still visible by 'dropbear -V'
Based on a patch by Hans Dedecker <dedeckeh@gmail.com>
Signed-off-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [remove trailing _]
- 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.
- Security: dropbearconvert import of OpenSSH keys could run arbitrary code as
the local dropbearconvert user when parsing malicious key files
- 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.
- Security: dbclient or dropbear server could expose process memory to the
running user if compiled with DEBUG_TRACE and running with -v
The security issues were reported by an anonymous researcher working with
Beyond Security's SecuriTeam Secure Disclosure www.beyondsecurity.com/ssd.html
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
Fix a „semantic typo“ introduced in b78aae793e,
where TARGET_INIT_PATH was used instead of CONFIG_TARGET_INIT_PATH.
Signed-off-by: Dario Ernst <Dario.Ernst@riverbed.com>
Update the dropbear package to version 2016.73, refresh patches.
The measured .ipk sizes on an x86_64 build are:
94588 dropbear_2015.71-3_x86_64.ipk
95316 dropbear_2016.73-1_x86_64.ipk
This is an increase of roughly 700 bytes after compression.
Tested-by: Kevin Darbyshire-Bryant <kevin@darbyshire-bryant.me.uk>
Signed-off-by: Jo-Philipp Wich <jo@mein.io>
The option --disable-utmpx was deleted by accident in commit 7545c1d;
add it again to the CONFIGURE_ARGS list
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
A dropbear instance having an interface config won't start if the interface is down as no
IP address is available.
Adding interface triggers for each configured interface executing the dropbear reload script
will start the dropbear instance when the interface is up.
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
Utmp support tracks who is currenlty logged in by logging info to the file /var/run/utmp (supported by busybox)
Putuline support will use the utmp structure to write to the utmp file
Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
While technically required by the RFC, they are usually completely
unused (DSA), or have security issues (3DES, CBC)
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
SVN-Revision: 46814
This enables passworldless login for root via SSH whenever no root
password is set (e.g. after reset, flashing without keeping config
or in failsafe) and removes telnet support alltogether.
Signed-off-by: Steven Barth <steven@midlink.org>
SVN-Revision: 46809
[base-files] shell-scripting: fix wrong usage of '==' operator
normally the '==' is used for invoking a regex parser and is a bashism.
all of the fixes just want to compare a string. the used busybox-ash
will silently "ignore" this mistake, but make it portable/clean at least.
this patch does not change the behavior/logic of the scripts.
Signed-off-by: Bastian Bittorf <bittorf@bluebottle.com>
SVN-Revision: 42911
Use network_get_ipaddrs_all to get all ip-addresses of an interface. If the
function fails, the interface does not exists or has not any suiteable ip
addresses assigned.
Use the returned ip-address(es) to construct the dropbear listen address.
Signed-off-by: Mathias Kresin <openwrt@kresin.me>
SVN-Revision: 42857
somebody started to set a function returncode in the validation
stuff and everybody copies it, e.g.
myfunction()
{
fire_command
return $?
}
a function automatically returns with the last returncode,
so we can safely remove the command 'return $?'. reference:
http://tldp.org/LDP/abs/html/exit-status.html
"The last command executed in the function or script determines the exit status."
Signed-off-by: Bastian Bittorf <bittorf@bluebottle.com>
SVN-Revision: 42278
Disable MIPS16 to prevent it negatively affecting performance.
Observed was a increase of connection delay from ~6 to ~11 seconds
and a reduction of scp speed from 1.1MB/s to 710kB/s on brcm63xx.
Fixes#15209.
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
SVN-Revision: 42250
Add a further upstream commit to more closely match the keepalive
to OpenSSH.
Should now really fix#17523.
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
SVN-Revision: 42249
Don't send SSH_MSG_UNIMPLEMENTED for keepalive responses, which broke
at least putty.
Fixes#17522 / #17523.
Signed-off-by: Jonas Gorski <jogo@openwrt.org>
SVN-Revision: 42162
Rosen Penev