Bug 594724 (CVE-2016-7044, CVE-2016-7045) – <net-irc/irssi-0.8.20-r1: Heap corruption and missing boundary checks

• Product: Gentoo Security
• Status: RESOLVED FIXED

[Description Matthew Thode ( prometheanfire ) 2016-09-21 19:55:31 UTC]

Affected:
>=0.8.17
<0.8.20

heap corruption and missing boundary checks
===========================================
CWE Classification: CWE-20, CWE-823, CWE-126, CWE-122

CVE-2016-7044 [1] was assigned to bug 1
CVE-2016-7045 [2] was assigned to bug 2


Description
-----------

Gabriel Campana and Adrien Guinet from Quarkslab reported two remote
crash and heap corruption vulnerabilites in Irssi's format parsing
code.

They also provided us with proof of concept exploit code and patches
to fix those issues.


Impact
------

Remote crash and heap corruption. Remote code execution seems
difficult since only Nuls are written.


Detailed analysis
-----------------

Based on analysis Provided by Gabriel Campana and Adrien Guinet from
Quarkslab:

Bug 1

The unformat_24bit_color() function is called by format_send_to_gui()
to decode 24bit color codes into their components. The pointer is
advanced unconditionally without checking if a complete code was
supplied.

Thus, after the return of unformat_24bit_color(), ptr might be invalid
and point out of the buffer.

Bug 2

The format_send_to_gui() function does not validate the length of the
string before incrementing the `ptr' pointer in all cases.

If that happens, the pointer `ptr' can be incremented twice and thus
end past the boundaries of the original `dup' buffer.


Affected versions
-----------------

Irssi 0.8.17-beta up to and including 0.8.19 up to 0.8.19-219-g52fedea

Bug 1 affects only Irssis compiled with true-color enabled.
Bug 2 affects all Irssis regardless of compilation flags.


Fixed in
--------

Irssi 0.8.20


Recommended action
------------------

Upgrade to Irssi 0.8.20. Irssi 0.8.20 is a maintenance release
without any new features.

After installing the updated packages, one can issue the /upgrade
command to load the new binary. TLS connections will require
/reconnect. If the buf.pl script is loaded and symlinked into
~/.irssi/scripts/autorun, text buffer content will be saved and
restored.


Fallback action
---------------

Distributions which need to remain on Irssi 0.8.17 are strongly urged
to apply the patch and provide updated packages.

Those who cannot upgrade right now, but with Perl support enabled in
their Irssi, can load the following script and add it to
~/.irssi/scripts/autorun as a first aid to mitigating these issues: 

https://irssi.org/security/sa_patch.pl


Patch
-----

https://github.com/irssi/irssi/commit/295a4b77f07f14602eeaa371f00ddbf09910c82b


References
----------
[1] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7044
[2] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7045

[Comment 1 Matthew Thode ( prometheanfire ) 2016-09-21 19:58:12 UTC]

arches, please quick stabilize =net-irc/irssi-0.8.20 for the bug

@security - Not sure if it should be A3 or B3

[Comment 2 Agostino Sarubbo 2016-09-21 21:46:26 UTC]

amd64 stable

[Comment 3 Agostino Sarubbo 2016-09-21 21:46:53 UTC]

x86 stable

[Comment 4 Tobias Klausmann (RETIRED) 2016-09-22 10:58:21 UTC]

Stable on alpha.

[Comment 5 Jeroen Roovers (RETIRED) 2016-09-23 13:31:59 UTC]

Stable for HPPA PPC64.

[Comment 6 Agostino Sarubbo 2016-09-29 09:38:46 UTC]

sparc stable

[Comment 7 Agostino Sarubbo 2016-09-29 12:39:40 UTC]

ppc stable

[Comment 8 Agostino Sarubbo 2016-09-29 13:15:30 UTC]

arm stable

[Comment 9 Agostino Sarubbo 2016-09-29 13:32:06 UTC]

ia64 stable.

Maintainer(s), please cleanup.
Security, please add it to the existing request, or file a new one.

[Comment 10 Patrice Clement (RETIRED) 2016-09-29 13:39:15 UTC]

I think it'd have made more sense to stabilise -r1 since it includes another fix for another CVE (including the fix for the current bug). See bug 595172.

Does someone mind if I mark -r1 stable via the ALLARCHES policy and clean up versions < -r1? so that we can kill two birds in one stone.

[Comment 11 Sven Wegener 2016-09-30 17:01:19 UTC]

I've just ported the keyword and performed a cleanup.

[Comment 12 Aaron Bauman (RETIRED) 2016-11-11 12:56:51 UTC]

No proofing of arbitrary code execution in this as mentioned by the CWE.  Re-designating.

GLSA Vote: No