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
4.9 KiB
Text
137 lines
4.9 KiB
Text
-----BEGIN PGP SIGNED MESSAGE-----
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Hash: SHA1
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=============================================================================
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FreeBSD-SA-10:04.jail Security Advisory
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The FreeBSD Project
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Topic: Insufficient environment sanitization in jail(8)
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Category: core
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Module: jail
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Announced: 2010-05-27
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Credits: Aaron D. Gifford
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Affects: FreeBSD 8.0
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Corrected: 2010-05-27 03:15:04 UTC (RELENG_8, 8.1-PRERELEASE)
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2010-05-27 03:15:04 UTC (RELENG_8_0, 8.0-RELEASE-p3)
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CVE Name: CVE-2010-2022
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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 jail(2) system call allows a system administrator to lock a process
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and all of its descendants inside an environment with a very limited
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ability to affect the system outside that environment, even for
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processes with superuser privileges. It is an extension of, but
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far more powerful than, the traditional UNIX chroot(2) system call.
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By design, neither the chroot(2) nor the jail(2) system call modify
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existing open file descriptors of the calling process, in order to
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allow programmers to make fine grained access control and privilege
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separation.
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The jail(8) utility creates a new jail or modifies an existing jail,
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optionally imprisoning the current process (and future descendants)
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inside it.
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II. Problem Description
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The jail(8) utility does not change the current working directory while
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imprisoning. The current working directory can be accessed by its
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descendants.
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III. Impact
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Access to arbitrary files may be possible if an attacker managed to obtain
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the descriptor of the current working directory before the jail call.
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Such descriptor would be inherited by all descendants of the first process
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that starts the jail, unless an intermediate process changes the current
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working directory inside the jail.
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By default, the FreeBSD /etc/rc.d/jail script, which can be enabled
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using the jail_* rc.conf(5) variables, is not affected by this issue.
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This is due to the default jail flags ("-l -U root") used to start a
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jail as these flags will result in jail(8) performing a chdir(2) call.
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If the rc.conf(5) variables jail_flags or jail_<jname>_flags has been
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set, and do not include '-l -U root', the jails are affected by the
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vulnerability.
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IV. Workaround
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Include the "-l -U root" arguments to the jail(8) command when
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starting the jail.
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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 8-STABLE, or to the RELENG_8_0
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security branch dated after the correction date.
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2) To update your vulnerable system via a source code patch:
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The following patches have been verified to apply to FreeBSD 8.0 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 http://security.FreeBSD.org/patches/SA-10:04/jail.patch
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# fetch http://security.FreeBSD.org/patches/SA-10:04/jail.patch.asc
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b) Execute the following commands as root:
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# cd /usr/src
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# patch < /path/to/patch
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# cd /usr/src/usr.sbin/jail
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# make obj && make depend && make && make install
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3) To update your vulnerable system via a binary patch:
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Systems running 8.0-RELEASE on the i386 or amd64 platforms can be
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updated via the freebsd-update(8) utility:
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# freebsd-update fetch
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# freebsd-update install
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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_8
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src/usr.sbin/jail/jail.c 1.33.2.2
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RELENG_8_0
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src/UPDATING 1.632.2.7.2.6
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src/sys/conf/newvers.sh 1.83.2.6.2.6
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src/usr.sbin/jail/jail.c 1.33.2.1.2.2
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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/8/ r208586
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releng/8.0/ r208586
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- -------------------------------------------------------------------------
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VII. References
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http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-2022
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The latest revision of this advisory is available at
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http://security.FreeBSD.org/advisories/FreeBSD-SA-10:04.jail.asc
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