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)
111 lines
3.6 KiB
Text
111 lines
3.6 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-04:03.jail Security Advisory
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The FreeBSD Project
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Topic: Jailed processes can attach to other jails
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Category: core
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Module: kernel
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Announced: 2004-02-25
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Credits: JAS Group (http://www.cs.mu.oz.au/jas/)
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Affects: FreeBSD 5.1-RELEASE
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FreeBSD 5.2-RELEASE
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Corrected: 2004-02-19 23:26:39 UTC (RELENG_5_2, 5.2.1-RC2)
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2004-02-25 20:03:35 UTC (RELENG_5_1, 5.1-RELEASE-p14)
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CVE Name: CAN-2004-0126
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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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The jail(2) system call allows a system administrator to lock up a
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process and all its descendants inside a closed environment with very
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limited ability to affect the system outside that environment, even
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for processes with superuser privileges. It is an extension of, but
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far more stringent than, the traditional Unix chroot(2) system call.
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The jail_attach(2) system call, which was introduced in FreeBSD 5
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before 5.1-RELEASE, allows a non-jailed process to permanently move
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into an existing jail.
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II. Problem Description
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A programming error has been found in the jail_attach(2) system call
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which affects the way that system call verifies the privilege
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level of the calling process. Instead of failing immediately if the
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calling process was already jailed, the jail_attach(2) system call
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would fail only after changing the calling process's root directory.
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III. Impact
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A process with superuser privileges inside a jail could change its
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root directory to that of a different jail, and thus gain full read
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and write access to files and directories within the target jail.
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IV. Workaround
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No workaround is available.
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V. Solution
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Do one of the following:
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1) Upgrade your vulnerable system to 5.2.1-RELEASE, or to the
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RELENG_5_2 or RELENG_5_1 security branch dated after the correction
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date.
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OR
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2) Patch your present system:
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The following patch has been verified to apply to FreeBSD 5.1 and 5.2
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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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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:03/jail.patch
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# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:03/jail.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_5_2
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src/sys/kern/kern_jail.c 1.34.2.1
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RELENG_5_1
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src/UPDATING 1.251.2.16
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src/sys/conf/newvers.sh 1.50.2.16
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src/sys/kern/kern_jail.c 1.33.2.1
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- -------------------------------------------------------------------------
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VII. References
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<URL:http://www.cs.mu.oz.au/jas/>
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