FreeBSD Security Advisories
2004-Jun-07 21:07 UTC
FreeBSD Security Advisory FreeBSD-SA-04:12.jailroute
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============================================================================FreeBSD-SA-04:12.jailroute
Security Advisory
The FreeBSD Project
Topic: Jailed processes can manipulate host routing tables
Category: core
Module: kernel
Announced: 2004-06-07
Credits: Pawel Malachowski
Affects: All FreeBSD 4.x releases prior to 4.10-RELEASE
Corrected: 2004-04-06 20:11:53 UTC (RELENG_4)
2004-06-07 17:44:44 UTC (RELENG_4_9, 4.9-RELEASE-p10)
2004-06-07 17:42:42 UTC (RELENG_4_8, 4.8-RELEASE-p23)
CVE Name: CAN-2004-0125
FreeBSD only: YES
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit
<URL:http://www.freebsd.org/security/>.
I. Background
The jail(2) system call allows a system administrator to lock up a
process and all its descendants inside a closed environment with very
limited ability to affect the system outside that environment, even
for processes with superuser privileges. It is an extension of, but
far more stringent than, the traditional Unix chroot(2) system call.
The FreeBSD kernel maintains internal routing tables for the purpose
of determining which interface should be used to transmit packets.
These routing tables can be manipulated by user processes running
with superuser privileges by sending messages over a routing socket.
II. Problem Description
A programming error resulting in a failure to verify that an attempt
to manipulate routing tables originated from a non-jailed process.
III. Impact
Jailed processes running with superuser privileges could modify host
routing tables. This could result in a variety of consequences including
packets being sent via an incorrect network interface and packets being
discarded entirely.
IV. Workaround
No workaround is available.
V. Solution
Do one of the following:
1) Upgrade your vulnerable system to 4.10-RELEASE, or to the RELENG_4_8
or RELENG_4_9 security branch dated after the correction date.
OR
2) Patch your present system:
The following patch has been verified to apply to the FreeBSD 4.8 and
4.9 systems.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:12/jailroute.patch
# fetch
ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-04:12/jailroute.patch.asc
b) Apply the patch.
# cd /usr/src
# patch < /path/to/patch
c) Recompile your kernel as described in
<URL:http://www.freebsd.org/handbook/kernelconfig.html> and reboot the
system.
VI. Correction details
The following list contains the revision numbers of each file that was
corrected in FreeBSD.
Branch Revision
Path
- -------------------------------------------------------------------------
RELENG_4
src/sys/net/rtsock.c 1.44.2.13
RELENG_4_9
src/UPDATING 1.73.2.89.2.11
src/sys/conf/newvers.sh 1.44.2.32.2.11
src/sys/net/rtsock.c 1.44.2.11.4.1
RELENG_4_8
src/UPDATING 1.73.2.80.2.26
src/sys/conf/newvers.sh 1.44.2.29.2.24
src/sys/net/rtsock.c 1.44.2.11.2.1
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At 22:06 07/06/2004, FreeBSD Security Advisories wrote:>FreeBSD-SA-04:12.jailroute Security Advisory >Affects: All FreeBSD 4.x releases prior to 4.10-RELEASEAs a few people have noted, this should read "FreeBSD 4.8 and 4.9"; this bug never existed in earlier versions of FreeBSD. That said, FreeBSD 4.7 and earlier are no longer officially supported, and it is highly recommended that people upgrade to a newer version, since there have been recent security advisories concerning issues to which earlier releases are still vulnerable.>V. Solution>Do one of the following: > >1) Upgrade your vulnerable system to 4.10-RELEASE, or to the RELENG_4_8 >or RELENG_4_9 security branch dated after the correction date. > >OR > >2) Patch your present system:or, as usual, 3) If you are running an affected release, you can use FreeBSD Update: # cd /usr/ports/security/freebsd-update && make all install # cp /usr/local/etc/freebsd-update.conf.sample /usr/local/etc/freebsd-update.conf # /usr/local/sbin/freebsd-update fetch # /usr/local/sbin/freebsd-update install For more details, see http://www.daemonology.net/freebsd-update/ . Note that this is something I'm providing personally; it is in no way endorsed by the Security Officer or the Project as a whole. Colin Percival