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                             CERT-Renater

                 Note d'Information No. 2023/VULN003

_____________________________________________________________________

DATE                : 17/01/2023

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): Systems running libXpm versions prior to 3.5.15.

=====================================================================
https://lists.x.org/archives/xorg/2023-January/061244.html
_____________________________________________________________________

X.Org Security Advisory:  January 17, 2023

Issues handling XPM files in libXpm prior to 3.5.15
===================================================

Three issues have been found in the libXpm library code to read XPM
files in libXpm 3.5.14 and earlier releases.

1) CVE-2022-46285: Infinite loop on unclosed comments

When reading XPM images from a file with libXpm 3.5.14 or older,
if a comment in the file is not closed (i.e. a C-style comment
starts with "/*" and is missing the closing "*/"), the ParseComment()
function will loop forever calling getc() to try to read the rest of
the comment, failing to notice that it has returned EOF, which may
cause a denial of service to the calling program.

This issue was found by Marco Ivaldi of the Humanativa Group's HN
Security team.

The fix is provided in
https://gitlab.freedesktop.org/xorg/lib/libxpm/-/commit/a3a7c6dcc3b629d7650148

2) CVE-2022-44617: Runaway loop on width of 0 and enormous height

When reading XPM images from a file with libXpm 3.5.14 or older, if
a image has a width of 0 and a very large height, the ParsePixels()
function will loop over the entire height calling getc() and ungetc()
repeatedly, or in some circumstances, may loop seemingly forever,
which may cause a denial of service to the calling program when given
a small crafted XPM file to parse.

This issue was found by Martin Ettl.

The fix is provided in
https://gitlab.freedesktop.org/xorg/lib/libxpm/-/commit/f80fa6ae47ad4a5beacb28
and
https://gitlab.freedesktop.org/xorg/lib/libxpm/-/commit/c5ab17bcc34914c0b0707d

3) CVE-2022-4883: compression commands depend on $PATH

By default, on all platforms except MinGW, libXpm will detect if a
filename ends in .Z or .gz, and will when reading such a file fork off
an uncompress or gunzip command to read from via a pipe, and when
writing such a file will fork off a compress or gzip command to write
to via a pipe.

In libXpm 3.5.14 or older these are run via execlp(), relying on $PATH
to find the commands.  If libXpm is called from a program running with
raised privileges, such as via setuid, then a malicious user could set
$PATH to include programs of their choosing to be run with those
privileges.

This issue was found by Alan Coopersmith of the Oracle Solaris team.

The fix is provided in
https://gitlab.freedesktop.org/xorg/lib/libxpm/-/commit/515294bb8023a45ff91669
and
https://gitlab.freedesktop.org/xorg/lib/libxpm/-/commit/8178eb0834d82242e1edbc

libXpm 3.5.15 includes fixes for all three of these issues.  It also
adds a new configure option --disable-open-zfile that makes it easy
for people building libXpm to completely disable the code to fork
compression and uncompression programs if they do not have a need
for it in their use case.

X.Org thanks all of those who reported and fixed these issues, and
those who helped with the review and release of this advisory and
these fixes.

The X.Org security team would like to take this opportunity to remind
X client authors that current best practices suggest separating code
that requires privileges from the GUI, to reduce the risk of issues
like CVE-2022-4883.

-- 
      -Alan Coopersmith-              alan.coopersmith at oracle.com
        X.Org Security Response Team - xorg-security at lists.x.org



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