oss-security - CVE Request -- foomatic (foomatic-filters): foomatic-rip (debug mode) insecure temporary file use in renderer command line by processing PostScript data

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Date: Thu, 28 Jul 2011 17:00:08 +0200
From: Jan Lieskovsky <jlieskov@...hat.com>
To: "Steven M. Christey" <coley@...us.mitre.org>,
        Tim Waugh <twaugh@...hat.com>
CC: oss-security@...ts.openwall.com
Subject: CVE Request -- foomatic (foomatic-filters): foomatic-rip (debug mode)
 insecure temporary file use in renderer command line by processing PostScript
 data

Hello Josh, Steve, vendors,

   by further investigation of hplip CVE-2011-2722 issue:
   [2] https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2011-2722

Tim Waugh noticed the similar issue being present also in foomatic-rip
universal print filter, when debug mode is enabled. Further details:

It was found that foomatic-rip filter used insecurely created temporary
file for storage of PostScript data by rendering the data, intended to 
be sent to the PostScript filter, when the debug mode was enabled. A 
local attacker could use this flaw to conduct symlink attacks (overwrite 
arbitrary file accessible with the privileges of the user running the 
foomatic-rip universal print filter).

Relevant source code part (Perl script part / foomatic-rip.in):
===============================================================
    100 my $logfile = "/tmp/foomatic-rip";
   ..
   3454  # In debug mode save the data supposed to be fed
           into the
   3455  # renderer also into a file
   3456  if ($debug) {
   3457    $commandline = "tee -a ${logfile}.ps | ( $commandline )";
   3458  }

Note: The $logfile variable declaration (line #100) is not an insecure
       temporary file use issue itself, since this danger (and its proper
       usage) is documented in /etc/foomatic/filters.conf file.

Relevant source code part (C script part / renderer.c):
========================================================
    436  /* Save the data supposed to be fed into the renderer
           also int        o a file*/
    437  dstrprepend(commandline, "tee -a " LOG_FILE ".ps | ( ");
    438  dstrcat(commandline, ")");
    439  }

Note: The LOG_FILE variable declaration by itself is not an insecure
       temporary file use, since this danger (and its proper usage)
       is documented in /etc/foomatic/filters.conf file.

References:
[1] https://bugzilla.redhat.com/show_bug.cgi?id=726426

Credit: Issue discovered by Tim Waugh

Could you allocate a CVE id for this?

Thank you && Regards, Jan.
--
Jan iankko Lieskovsky / Red Hat Security Response Team

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