3571e53040
patches for easier mirroring, to eliminate a special copy, to make www.freebsd.org/security a full copy of security.freebsd.org and be eventually be the same. For now files are just sitting there. The symlinks are missing. Discussed on: www (repository location) Discussed with: simon (so)
141 lines
5.3 KiB
Text
141 lines
5.3 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-09:14.devfs Security Advisory
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The FreeBSD Project
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Topic: Devfs / VFS NULL pointer race condition
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Category: core
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Module: kern
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Announced: 2009-10-02
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Credits: Przemyslaw Frasunek
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Affects: FreeBSD 6.x and 7.x
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Corrected: 2009-05-18 10:41:59 UTC (RELENG_7, 7.2-STABLE)
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2009-10-02 18:09:56 UTC (RELENG_7_2, 7.2-RELEASE-p4)
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2009-10-02 18:09:56 UTC (RELENG_7_1, 7.1-RELEASE-p8)
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2009-10-02 18:09:56 UTC (RELENG_6, 6.4-STABLE)
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2009-10-02 18:09:56 UTC (RELENG_6_4, 6.4-RELEASE-p7)
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2009-10-02 18:09:56 UTC (RELENG_6_3, 6.3-RELEASE-p13)
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For general information regarding FreeBSD Security Advisories,
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including descriptions of the fields above, security branches, and the
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following sections, please visit <URL:http://security.FreeBSD.org/>.
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I. Background
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The device file system (devfs) provides access to system devices, such as
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storage devices and serial ports, via the file system namespace.
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VFS is the Virtual File System, which abstracts file system operations in
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the kernel from the actual underlying file system.
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II. Problem Description
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Due to the interaction between devfs and VFS, a race condition exists
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where the kernel might dereference a NULL pointer.
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III. Impact
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Successful exploitation of the race condition can lead to local kernel
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privilege escalation, kernel data corruption and/or crash.
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To exploit this vulnerability, an attacker must be able to run code with user
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privileges on the target system.
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IV. Workaround
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An errata note, FreeBSD-EN-09:05.null has been released simultaneously to
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this advisory, and contains a kernel patch implementing a workaround for a
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more broad class of vulnerabilities. However, prior to those changes, no
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workaround is available.
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V. Solution
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Perform one of the following:
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1) Upgrade your vulnerable system to 6-STABLE, or 7-STABLE, or to the
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RELENG_7_2, RELENG_7_1, RELENG_6_4, or RELENG_6_3 security branch
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dated after the correction date.
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2) To patch your present system:
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The following patches have been verified to apply to FreeBSD 6.3, 6.4,
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7.1, and 7.2 systems.
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a) Download the relevant patch from the location below, and verify the
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detached PGP signature using your PGP utility.
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[FreeBSD 6.x]
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# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch
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# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs6.patch.asc
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[FreeBSD 7.x]
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# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.patch
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# fetch http://security.FreeBSD.org/patches/SA-09:14/devfs7.patch.asc
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b) Apply the patch.
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# cd /usr/src
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# patch < /path/to/patch
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c) Recompile your kernel as described in
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<URL:http://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the
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system.
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VI. Correction details
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The following list contains the revision numbers of each file that was
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corrected in FreeBSD.
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CVS:
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Branch Revision
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Path
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- -------------------------------------------------------------------------
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RELENG_6
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src/sys/fs/devfs/devfs_vnops.c 1.114.2.17
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RELENG_6_4
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src/UPDATING 1.416.2.40.2.11
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src/sys/conf/newvers.sh 1.69.2.18.2.13
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src/sys/fs/devfs/devfs_vnops.c 1.114.2.16.2.2
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RELENG_6_3
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src/UPDATING 1.416.2.37.2.18
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src/sys/conf/newvers.sh 1.69.2.15.2.17
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src/sys/fs/devfs/devfs_vnops.c 1.114.2.15.2.1
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RELENG_7
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src/sys/fs/devfs/devfs_vnops.c 1.149.2.9
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RELENG_7_2
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src/UPDATING 1.507.2.23.2.7
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src/sys/conf/newvers.sh 1.72.2.11.2.8
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src/sys/fs/devfs/devfs_vnops.c 1.149.2.8.2.2
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RELENG_7_1
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src/UPDATING 1.507.2.13.2.11
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src/sys/conf/newvers.sh 1.72.2.9.2.12
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src/sys/fs/devfs/devfs_vnops.c 1.149.2.4.2.2
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- -------------------------------------------------------------------------
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Subversion:
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Branch/path Revision
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- -------------------------------------------------------------------------
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stable/6/ r197715
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releng/6.4/ r197715
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releng/6.3/ r197715
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stable/7/ r192301
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releng/7.2/ r197715
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releng/7.1/ r197715
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- -------------------------------------------------------------------------
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VII. References
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-09:14.devfs.asc
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