FreeBSD Security Advisory FreeBSD-SA-04:11.msync
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Thread: FreeBSD Security Advisory FreeBSD-SA-04:11.msync

  1. #1
    King Arana: Super Moderator
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    FreeBSD Security Advisory FreeBSD-SA-04:11.msync

    From Security Focus and their FreeBSD Security Advisory:

    FreeBSD-SA-04:11.msync Security Advisory
    The FreeBSD Project

    Topic: buffer cache invalidation implementation issues

    Category: core
    Module: sys
    Announced: 2004-05-26
    Credits: Stephan Uphoff <ups tree com>
    Matt Dillon <dillon apollo backplane com>
    Affects: All FreeBSD versions prior to the correction date
    Corrected: 2004-05-25 22:46:38 UTC (RELENG_4, 4.10-STABLE)
    2004-05-25 23:07:55 UTC (RELENG_5_2, 5.2.1-RELEASE-p8)
    2004-05-22 23:09:19 UTC (RELENG_4_10, 4.10-RELEASE)
    2004-05-25 23:01:21 UTC (RELENG_4_9, 4.9-RELEASE-p9)
    2004-05-25 23:01:19 UTC (RELENG_4_8, 4.8-RELEASE-p22)
    CVE Name: CAN-2004-0435
    FreeBSD only: YES

    For general information regarding FreeBSD Security Advisories,
    including descriptions of the fields above, security branches, and the
    following sections, please visit
    <URL:http://www.freebsd.org/security/>.

    I. Background

    The msync(2) system call is used by applications to request that
    modified memory pages are written to permanent storage.

    II. Problem Description

    Programming errors in the implementation of the msync(2) system call
    involving the MS_INVALIDATE operation lead to cache consistency
    problems between the virtual memory system and on-disk contents.

    III. Impact

    In some situations, a user with read access to a file may be able to
    prevent changes to that file from being committed to disk.

    IV. Workaround

    There is no workaround.

    V. Solution

    Perform one of the following:

    1) Upgrade your vulnerable system to 4-STABLE; or to the RELENG_5_2,
    RELENG_4_10, RELENG_4_9, or RELENG_4_8 security branch dated after the
    correction date.

    2) To patch your present system:

    The following patches have been verified to apply to FreeBSD 4.8, 4.9,
    4.10 and 5.2 systems.

    a) Download the relevant patch from the location below, and verify the
    detached PGP signature using your PGP utility.

    [FreeBSD 5.2]
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...1/msync5.patch
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...ync5.patch.asc

    [FreeBSD 4.8, 4.9, 4.10]
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...1/msync4.patch
    # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CE...ync4.patch.asc

    b) Apply the patch.

    # cd /usr/src
    # patch < /path/to/patch

    c) Recompile your kernel as described in
    <URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the
    system.

    VI. Correction details

    The following list contains the revision numbers of each file that was
    corrected in FreeBSD.

    Branch Revision
    Path
    - -------------------------------------------------------------------------
    RELENG_4
    src/sys/ufs/ufs/ufs_readwrite.c 1.65.2.16
    src/sys/vm/vm_map.c 1.187.2.30
    RELENG_4_10
    src/sys/ufs/ufs/ufs_readwrite.c 1.65.2.14.4.1
    src/sys/vm/vm_map.c 1.187.2.24.2.4
    RELENG_4_9
    src/UPDATING 1.73.2.89.2.10
    src/sys/conf/newvers.sh 1.44.2.32.2.10
    src/sys/ufs/ufs/ufs_readwrite.c 1.65.2.14.2.1
    src/sys/vm/vm_map.c 1.187.2.23.2.1
    RELENG_4_8
    src/UPDATING 1.73.2.80.2.25
    src/sys/conf/newvers.sh 1.44.2.29.2.23
    src/sys/ufs/ufs/ufs_readwrite.c 1.65.2.13.2.1
    src/sys/vm/vm_map.c 1.187.2.17.2.1
    RELENG_5_2
    src/UPDATING 1.282.2.16
    src/sys/conf/newvers.sh 1.56.2.15
    src/sys/ufs/ffs/ffs_vnops.c 1.119.2.1
    src/sys/vm/vm_object.c 1.317.2.1
    For the direct link to the article and added information about this new vulnerability,
    click here.
    Space For Rent.. =]

  2. #2
    Priapistic Monk KorpDeath's Avatar
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    Am I reading that wrong...."In some situations, a user with read access to a file may be able to
    prevent changes to that file from being committed to disk."

    If a user has read access only then I don't want them to be able to commit changes to that file to disk. Maybe Iit's been mis typed or I am misreading but.... huh?

    sexplain...
    Mankind have a great aversion to intellectual labor; but even supposing knowledge to be easily attainable, more people would be content to be ignorant than would take even a little trouble to acquire it.
    - Samuel Johnson

  3. #3
    King Arana: Super Moderator
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    I think that's part of the flaw. Dunno, but if not then it's a misprint from the article.
    Space For Rent.. =]

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