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)
147 lines
5.8 KiB
Text
147 lines
5.8 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-04:17.procfs Security Advisory
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The FreeBSD Project
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Topic: Kernel memory disclosure in procfs and linprocfs
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Category: core
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Module: sys
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Announced: 2004-12-01
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Credits: Bryan Fulton, Ted Unangst, and the SWAT analysis tool
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Coverity, Inc.
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Affects: All FreeBSD releases
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Corrected: 2004-12-01 21:33:35 UTC (RELENG_5, 5.3-STABLE)
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2004-12-01 21:34:23 UTC (RELENG_5_3, 5.3-RELEASE-p2)
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2004-12-01 21:34:43 UTC (RELENG_5_2, 5.2.1-RELEASE-p13)
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2004-12-01 21:33:57 UTC (RELENG_4, 4.10-STABLE)
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2004-12-01 21:35:10 UTC (RELENG_4_10, 4.10-RELEASE-p5)
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2004-12-01 21:35:57 UTC (RELENG_4_8, 4.8-RELEASE-p27)
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CVE Name: CAN-2004-1066
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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
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<URL:http://www.freebsd.org/security/>.
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I. Background
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The process file system, procfs(5), implements a view of the system
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process table inside the file system. It is normally mounted on
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/proc, and is required for the complete operation of programs such as
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ps(1) and w(1).
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The Linux process file system, linprocfs(5), emulates a subset of
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Linux's process file system and is required for the complete operation
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of some Linux binaries.
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II. Problem Description
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The implementation of the /proc/curproc/cmdline pseudofile in the procfs(5)
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file system on FreeBSD 4.x and 5.x, and of the /proc/self/cmdline
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pseudofile in the linprocfs(5) file system on FreeBSD 5.x reads a process'
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argument vector from the process address space. During this operation,
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a pointer was dereferenced directly without the necessary validation
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steps being performed.
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III. Impact
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A malicious local user could perform a local denial of service attack by
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causing a system panic; or he could read parts of kernel memory. Such
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memory might contain sensitive information, such as portions of the file
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cache or terminal buffers. This information might be directly useful, or
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it might be leveraged to obtain elevated privileges in some way. For
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example, a terminal buffer might contain a user-entered password.
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FreeBSD 4.x does not implement the /proc/self/cmdline pseudofile in
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its linprocfs(5) file system, and is therefore only affected if the
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procfs(5) file system is mounted.
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In its default configuration, FreeBSD 5.x does not utilize procfs(5)
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or linprocfs(5) and will therefore be unaffected by this vulnerability
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unless the configuration is changed.
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IV. Workaround
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Unmount the procfs and linprocfs file systems if they are mounted.
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Execute the following command as root:
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umount -A -t procfs,linprocfs
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Also, remove or comment out any lines in fstab(5) that reference
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`procfs' or `linprocfs', so that they will not be re-mounted at next
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reboot.
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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 4-STABLE or 5-STABLE, or to the
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RELENG_5_3, RELENG_5_2, RELENG_4_10, or RELENG_4_8 security branch dated
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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 4.8, 4.10,
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5.2, and 5.3 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 4.x]
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:17/procfs4.patch
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:17/procfs4.patch.asc
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[FreeBSD 5.x]
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:17/procfs5.patch
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:17/procfs5.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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Branch Revision
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Path
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- -------------------------------------------------------------------------
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RELENG_4
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src/sys/miscfs/procfs/procfs_status.c 1.20.2.6
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RELENG_4_10
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src/UPDATING 1.73.2.90.2.6
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src/sys/conf/newvers.sh 1.44.2.34.2.7
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src/sys/miscfs/procfs/procfs_status.c 1.20.2.5.4.1
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RELENG_4_8
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src/UPDATING 1.73.2.80.2.30
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src/sys/conf/newvers.sh 1.44.2.29.2.28
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src/sys/miscfs/procfs/procfs_status.c 1.20.2.4.8.2
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RELENG_5
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src/sys/compat/linprocfs/linprocfs.c 1.84.2.1
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src/sys/fs/procfs/procfs_status.c 1.52.2.1
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RELENG_5_3
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src/UPDATING 1.342.2.13.2.5
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src/sys/compat/linprocfs/linprocfs.c 1.84.4.1
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src/sys/conf/newvers.sh 1.62.2.15.2.7
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src/sys/fs/procfs/procfs_status.c 1.52.4.1
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RELENG_5_2
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src/UPDATING 1.282.2.21
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src/sys/compat/linprocfs/linprocfs.c 1.78.2.1
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src/sys/conf/newvers.sh 1.56.2.20
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src/sys/fs/procfs/procfs_status.c 1.49.2.1
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- -------------------------------------------------------------------------
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