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)
131 lines
5.1 KiB
Text
131 lines
5.1 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-09:13.pipe Security Advisory
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The FreeBSD Project
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Topic: kqueue pipe race conditions
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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
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Corrected: 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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Pipes are a form of inter-process communication (IPC) provided by the
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FreeBSD kernel. kqueue is an event management API that applications can
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use to monitor pipes and other kernel services.
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II. Problem Description
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A race condition exists in the pipe close() code relating to kqueues,
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causing use-after-free for kernel memory, which may lead to an
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exploitable NULL pointer vulnerability in the kernel, kernel memory
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corruption, and other unpredictable results.
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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 on
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the target system.
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IV. Workaround
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An errata notice, 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 to the RELENG_6_4, or
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RELENG_6_3 security branch 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 and 6.4.
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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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# fetch http://security.FreeBSD.org/patches/SA-09:13/pipe.patch
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# fetch http://security.FreeBSD.org/patches/SA-09:13/pipe.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/kern/kern_event.c 1.93.2.7
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src/sys/kern/kern_fork.c 1.252.2.8
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src/sys/kern/sys_pipe.c 1.184.2.6
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src/sys/sys/event.h 1.32.2.1
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src/sys/sys/pipe.h 1.29.2.1
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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/kern/kern_event.c 1.93.2.6.6.2
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src/sys/kern/kern_fork.c 1.252.2.7.4.2
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src/sys/kern/sys_pipe.c 1.184.2.4.2.3
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src/sys/sys/event.h 1.32.12.2
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src/sys/sys/pipe.h 1.29.16.2
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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/kern/kern_event.c 1.93.2.6.4.1
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src/sys/kern/kern_fork.c 1.252.2.7.2.1
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src/sys/kern/sys_pipe.c 1.184.2.2.6.3
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src/sys/sys/event.h 1.32.10.1
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src/sys/sys/pipe.h 1.29.12.1
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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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- -------------------------------------------------------------------------
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VII. References
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http://svn.freebsd.org/viewvc/base?view=revision&revision=179243
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-09:13.pipe.asc
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