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)
137 lines
5.9 KiB
Text
137 lines
5.9 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-03:10.ibcs2 Security Advisory
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The FreeBSD Project
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Topic: Kernel memory disclosure via ibcs2
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Category: core
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Module: sys
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Announced: 2003-08-10
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Credits: David Rhodus <drhodus@catpa.com>
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Affects: All FreeBSD releases up to and including 4.8-RELEASE-p2,
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5.1-RELEASE-p1
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Corrected: 2003-08-10 23:30:18 UTC (RELENG_4)
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2003-08-10 23:28:16 UTC (RELENG_5_1)
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2003-08-10 23:29:10 UTC (RELENG_5_0)
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2003-08-10 23:31:11 UTC (RELENG_4_8)
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2003-08-10 23:31:51 UTC (RELENG_4_7)
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2003-08-10 23:32:22 UTC (RELENG_4_6)
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2003-08-10 23:32:44 UTC (RELENG_4_5)
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2003-08-10 23:33:18 UTC (RELENG_4_4)
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2003-08-10 23:33:50 UTC (RELENG_4_3)
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2003-08-10 23:35:21 UTC (RELENG_3)
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FreeBSD only: YES
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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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FreeBSD contains a kernel option (IBCS2) and kernel loadable module
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(ibcs2.ko) that provide system call translation for running Intel
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Binary Compatibility Specification 2 (iBCS2) compliant programs.
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It is not enabled in FreeBSD by default.
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II. Problem Description
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The iBCS2 system call translator for statfs(2) erroneously used the
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user-supplied length parameter when copying a kernel data structure
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into userland. If the length parameter were larger than required,
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then instead of copying only the statfs-related data structure,
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additional kernel memory would also be made available to the user.
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III. Impact
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If iBCS2 support were enabled, a malicious user could call the iBCS2
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version of statfs(2) with an arbitrarily large length parameter,
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causing the kernel to return a large portion of kernel memory. Such
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memory might contain sensitive information, such as portions of the
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file cache or terminal buffers. This information might be directly
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useful, or it might be leveraged to obtain elevated privileges in some
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way. For example, a terminal buffer might include a user-entered
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password.
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iBCS2 support is only present if the system administrator has enabled
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it by including `option IBCS2' in the kernel configuration file, or
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loaded it dynamically using kldload(8) or by setting `ibcs2_enable' in
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rc.conf(5).
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IV. Workaround
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Disable iBCS2 support if it is enabled.
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V. Solution
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1) Upgrade your vulnerable system to 4.8-STABLE, or to any of the
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RELENG_4_8 (4.8-RELEASE-p3), RELENG_4_7 (4.7-RELEASE-p13), or
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RELENG_5_1 (5.1-RELEASE-p2) security branches dated after the
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respective correction dates.
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2) To patch your present system:
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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. The following patch
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has been tested to apply to all FreeBSD 3.x, 4.x, and 5.x releases.
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:10/ibcs2.patch
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-03:10/ibcs2.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>
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and reboot the 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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Path Revision
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Branch
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- -------------------------------------------------------------------------
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src/UPDATING
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RELENG_5_1 1.251.2.3
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RELENG_5_0 1.229.2.16
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RELENG_4_8 1.73.2.80.2.5
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RELENG_4_7 1.73.2.74.2.16
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RELENG_4_6 1.73.2.68.2.44
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RELENG_4_5 1.73.2.50.2.46
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RELENG_4_4 1.73.2.43.2.47
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RELENG_4_3 1.73.2.28.2.34
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src/sys/conf/newvers.sh
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RELENG_5_1 1.50.2.4
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RELENG_5_0 1.48.2.11
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RELENG_4_8 1.44.2.29.2.4
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RELENG_4_7 1.44.2.26.2.15
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RELENG_4_6 1.44.2.23.2.33
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RELENG_4_5 1.44.2.20.2.30
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RELENG_4_4 1.44.2.17.2.38
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RELENG_4_3 1.44.2.14.2.24
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src/sys/i386/ibcs2/ibcs2_stat.c
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RELENG_4 1.10.2.1
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RELENG_5_1 1.21.2.1
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RELENG_5_0 1.16.2.2
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RELENG_4_8 1.10.14.1
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RELENG_4_7 1.10.12.1
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RELENG_4_6 1.10.10.1
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RELENG_4_5 1.10.8.1
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RELENG_4_4 1.10.6.1
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RELENG_4_3 1.10.4.1
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RELENG_3 1.8.2.1
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- -------------------------------------------------------------------------
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