[ GLSA 200408-24 ] Linux Kernel: Multiple information leaks

From: Tim Yamin (plasmaroo_at_gentoo.org)
Date: 08/26/04

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    Gentoo Linux Security Advisory GLSA 200408-24
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                                                 http://security.gentoo.org/
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       Severity: Normal
          Title: Linux Kernel: Multiple information leaks
           Date: August 25, 2004
           Bugs: #59378, #59905, #59769
             ID: 200408-24

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    Synopsis
    ========

    Multiple information leaks have been found in the Linux kernel,
    allowing an attacker to obtain sensitive data which may be used for
    further exploitation of the system.

    Background
    ==========

    The Linux kernel is responsible for managing the core aspects of a
    GNU/Linux system, providing an interface for core system applications
    as well as providing the essential structure and capability to access
    hardware that is needed for a running system.

    Affected packages
    =================

         -------------------------------------------------------------------
          Kernel / Unaffected / Remerge
         -------------------------------------------------------------------
       1 aa-sources ................. *>= 2.4.23-r2 .................. YES
          ............................. >= 2.6.5-r5 ................... YES
       2 alpha-sources .............. >= 2.4.21-r12 ......................
       3 ck-sources ................. *>= 2.4.26-r1 .................. YES
          ............................. >= 2.6.7-r5 ................... YES
       4 development-sources .......... >= 2.6.8 .........................
       5 gentoo-dev-sources ......... >= 2.6.7-r12 .......................
       6 gentoo-sources ............ *>= 2.4.19-r22 ......................
          ........................... *>= 2.4.20-r25 ......................
          ........................... *>= 2.4.22-r16 ......................
          ............................ *>= 2.4.25-r9 ......................
          ............................ >= 2.4.26-r9 .......................
       7 grsec-sources ........... >= 2.4.27.2.0.1-r1 ....................
       8 gs-sources .............. >= 2.4.25_pre7-r11 ....................
       9 hardened-dev-sources ........ >= 2.6.7-r7 .......................
      10 hardened-sources ........... >= 2.4.27-r1 .......................
      11 hppa-dev-sources .......... >= 2.6.7_p14-r1 .....................
      12 hppa-sources .............. >= 2.4.26_p7-r1 ................. YES
      13 ia64-sources ............... >= 2.4.24-r10 ......................
      14 mips-sources ............... *>= 2.4.25-r8 ......................
          ............................ *>= 2.4.26-r8 ......................
          ............................ *>= 2.6.4-r8 .......................
          ............................ *>= 2.6.6-r8 .......................
          ............................. >= 2.6.7-r5 .......................
      15 mm-sources ................ >= 2.6.8_rc4-r1 .....................
      16 openmosix-sources .......... >= 2.4.24-r4 .......................
      17 pac-sources ................ >= 2.4.23-r12 ......................
      18 pegasos-dev-sources .......... >= 2.6.8 .........................
      19 rsbac-sources .............. >= 2.4.26-r5 .......................
      20 rsbac-dev-sources ........... >= 2.6.7-r5 .......................
      21 selinux-sources ............ >= 2.4.26-r3 .......................
      22 sparc-sources .............. >= 2.4.27-r1 .......................
      23 uclinux-sources .......... *>= 2.4.26_p0-r6 .....................
          ........................... >= 2.6.7_p0-r5 ......................
      24 usermode-sources ........... *>= 2.4.24-r9 ......................
          ............................ *>= 2.4.26-r6 ......................
          ............................. >= 2.6.6-r6 .......................
      25 vanilla-sources .............. >= 2.4.27 ........................
      26 vserver-sources .......... >= 2.4.26.1.28-r4 ....................
      27 win4lin-sources ............ *>= 2.4.26-r6 ......................
          ............................. >= 2.6.7-r2 .......................
      28 wolk-sources ................ *>= 4.9-r14 .......................
          ............................ *>= 4.11-r10 .......................
          ............................. >= 4.14-r7 ........................
      29 xbox-sources ............... *>= 2.4.27-r1 ......................
          ............................. >= 2.6.7-r5 .......................
         -------------------------------------------------------------------
          NOTE: Packages marked with "Remerge" as "YES" require a re-merge
                even though Portage does not indicate a newer version!
         -------------------------------------------------------------------
          29 affected packages on all of their supported architectures.
         -------------------------------------------------------------------

    Description
    ===========

    The Linux kernel allows a local attacker to obtain sensitive kernel
    information by gaining access to kernel memory via several leaks in the
    /proc interfaces. These vulnerabilities exist in various drivers which
    make up a working Linux kernel, some of which are present across all
    architectures and configurations.

    CAN-2004-0415 deals with addressing invalid 32 to 64 bit conversions in
    the kernel, as well as insecure direct access to file offset pointers
    in kernel code which can be modified by the open(...), lseek(...) and
    other core system I/O functions by an attacker.

    CAN-2004-0685 deals with certain USB drivers using uninitialized
    structures and then using the copy_to_user(...) kernel call to copy
    these structures. This may leak uninitialized kernel memory, which can
    contain sensitive information from user applications.

    Finally, a race condition with the /proc/.../cmdline node was found,
    allowing environment variables to be read while the process was still
    spawning. If the race is won, environment variables of the process,
    which might not be owned by the attacker, can be read.

    Impact
    ======

    These vulnerabilities allow a local unprivileged attacker to access
    segments of kernel memory or environment variables which may contain
    sensitive information. Kernel memory may contain passwords, data
    transferred between processes, any memory which applications did not
    clear upon exiting as well as the kernel cache and kernel buffers.

    This information may be used to read sensitive data, open other attack
    vectors for further exploitation or cause a Denial of Service if the
    attacker can gain superuser access via the leaked information.

    Workaround
    ==========

    There is no temporary workaround for any of these information leaks
    other than totally disabling /proc support - otherwise, a kernel
    upgrade is required. A list of unaffected kernels is provided along
    with this announcement.

    Resolution
    ==========

    Users are encouraged to upgrade to the latest available sources for
    their system:

         # emerge sync
         # emerge -pv your-favorite-sources
         # emerge your-favorite-sources

         # # Follow usual procedure for compiling and installing a kernel.
         # # If you use genkernel, run genkernel as you would normally.

    References
    ==========

       [ 1 ] CAN-2004-0415
             http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0415
       [ 2 ] CAN-2004-0685
             http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0685

    Availability
    ============

    This GLSA and any updates to it are available for viewing at
    the Gentoo Security Website:

       http://security.gentoo.org/glsa/glsa-200408-24.xml

    Concerns?
    =========

    Security is a primary focus of Gentoo Linux and ensuring the
    confidentiality and security of our users machines is of utmost
    importance to us. Any security concerns should be addressed to
    security@gentoo.org or alternatively, you may file a bug at
    http://bugs.gentoo.org.

    License
    =======

    Copyright 2004 Gentoo Foundation, Inc; referenced text
    belongs to its owner(s).

    The contents of this document are licensed under the
    Creative Commons - Attribution / Share Alike license.

    http://creativecommons.org/licenses/by-sa/1.0

    
    



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