[Full-Disclosure] MDKSA-2003:085 - Updated gdm packages fix vulnerabilities

From: Mandrake Linux Security Team (security_at_linux-mandrake.com)
Date: 08/22/03

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    To: full-disclosure@lists.netsys.com
    Date: 22 Aug 2003 00:10:27 -0000

    Hash: SHA1


                    Mandrake Linux Security Update Advisory

    Package name: gdm
    Advisory ID: MDKSA-2003:085
    Date: August 21st, 2003

    Affected versions: 9.0, 9.1, Corporate Server 2.1

    Problem Description:

     Several vulnerabilities were discovered in versions of gdm prior to The first vulnerability is that any user can read any text
     file on the system due to code originally written to be run as the user
     logging in was in fact being run as the root user. This code is what
     allows the examination of the ~/.xsession-errors file. If a user makes
     a symlink from this file to any other file on the system during the
     session and ensures that the session lasts less than ten seconds, the
     user can read the file provided it was readable as a text file.
     Another two vulnerabilities were found in the XDMCP code that could be
     exploited to crash the main gdm daemon which would inhibit starting
     any new sessions (although the current session would be unaffected).
     The first problem here is due to the indirect query structure being
     used right after being freed due to a missing 'continue' statement in a
     loop; this happens if a choice of server expired and the client tried
     to connect.
     The second XDMCP problem is that when authorization data is being
     checked as a string, the length is not checked first. If the data is
     less than 18 bytes long, the daemon may wander off the end of the
     string a few bytes in the strncmp which could cause a SEGV.
     These updated packages bring gdm to version which is not
     vulnerable to any of these problems. Also note that XDMCP support is
     disabled by default in gdm.


    Updated Packages:
     Corporate Server 2.1:
     47a2d84bfff0e842657e789e085b434d corporate/2.1/RPMS/gdm-
     8536d89374219e42ad6ca6c441ffb0d1 corporate/2.1/RPMS/gdm-Xnest-
     35ab7f8231548f1daa4571bfb5e77054 corporate/2.1/SRPMS/gdm-

     Corporate Server 2.1/x86_64:
     252fc231c85e88411ca50a05f0404688 x86_64/corporate/2.1/RPMS/gdm-
     3f8b47c14e0d7fc4c2d76171e3ee0b5a x86_64/corporate/2.1/RPMS/gdm-Xnest-
     35ab7f8231548f1daa4571bfb5e77054 x86_64/corporate/2.1/SRPMS/gdm-

     Mandrake Linux 9.0:
     47a2d84bfff0e842657e789e085b434d 9.0/RPMS/gdm-
     8536d89374219e42ad6ca6c441ffb0d1 9.0/RPMS/gdm-Xnest-
     35ab7f8231548f1daa4571bfb5e77054 9.0/SRPMS/gdm-

     Mandrake Linux 9.1:
     9d8a97cc5f475f16eeb73caa9d7d8e6b 9.1/RPMS/gdm-
     4f866c5b5b4903d1b0751bcb6dc28d0f 9.1/RPMS/gdm-Xnest-
     91f0ff2421135e32f604d6cb82081439 9.1/SRPMS/gdm-

     Mandrake Linux 9.1/PPC:
     0cb8fbd74766c4d0036cab36d57b6081 ppc/9.1/RPMS/gdm-
     fb0df358c4d6c9a7cf3982c4d3258004 ppc/9.1/RPMS/gdm-Xnest-
     91f0ff2421135e32f604d6cb82081439 ppc/9.1/SRPMS/gdm-

    Bug IDs fixed (see https://qa.mandrakesoft.com for more information):

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    All packages are signed by MandrakeSoft for security. You can obtain
    the GPG public key of the Mandrake Linux Security Team by executing:

      gpg --recv-keys --keyserver www.mandrakesecure.net 0x22458A98

    Please be aware that sometimes it takes the mirrors a few hours to

    You can view other update advisories for Mandrake Linux at:


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    If you want to report vulnerabilities, please contact


    Type Bits/KeyID Date User ID
    pub 1024D/22458A98 2000-07-10 Linux Mandrake Security Team
      <security linux-mandrake.com>
    Version: GnuPG v1.0.7 (GNU/Linux)

    -----END PGP SIGNATURE-----

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