[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Search]
[FreeBSD] Schwachstelle im Pipe Code - FreeBSD-SA-09:13.pipe
- To: win-sec-ssc-l_AT_lists.lrz-muenchen.de
- Subject: [FreeBSD] Schwachstelle im Pipe Code - FreeBSD-SA-09:13.pipe
- From: WiN Site Security Contacts <win-sec-ssc_AT_lists.dfn-cert.de>
- Date: Mon, 5 Oct 2009 17:42:11 +0200 (CEST)
- Reply-to: win-sec_AT_cert.dfn.de
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Liebe Kolleginnen und Kollegen,
soeben erreichte uns nachfolgende Warnung des FreeBSD Security
Officers.Wir geben diese Informationen unveraendert an Sie weiter.
Race Condition zwischen Pipe close() und kqueue im FreeBSD Kernel
Im FreeBSD Kernel besteht eine Race Condition zwischen dem Code zum
Schliessen (close) von Pipes und dem kqueue Event API. Diese fuehrt
dazu, dass ein bereits freigegebener Pointer erneut dereferenziert
wird (use after free). Da der Zeiger unter Umstaenden den Wert NULL
hat, koennen lokale Angreifer die Schwachstelle dazu ausnutzen,
beliebigen Code mit den Rechten des Kernels auszufuehren, indem Sie
Seiten mit ausfuehrbaren Code an diese virtuelle Adresse einblenden.
Betroffen sind die folgenden Software Pakete und Plattformen:
Paket kern
FreeBSD Versionen vor den folgenden Erscheinungsdaten:
2009-10-02 18:09:56 UTC (RELENG_6, 6.4-STABLE)
2009-10-02 18:09:56 UTC (RELENG_6_4, 6.4-RELEASE-p7)
2009-10-02 18:09:56 UTC (RELENG_6_3, 6.3-RELEASE-p13)
Vom Hersteller werden ueberarbeitete Pakete zur Verfuegung gestellt.
Hersteller Advisory:
http://security.FreeBSD.org/advisories/FreeBSD-SA-09:13.pipe.asc
(c) der deutschen Zusammenfassung bei DFN-CERT Services GmbH; die
Verbreitung, auch auszugsweise, ist nur unter Hinweis auf den Urheber,
DFN-CERT Services GmbH, und nur zu nicht kommerziellen Zwecken
gestattet.
Mit freundlichen Gruessen,
Klaus Moeller, DFN-CERT
- --
Dipl. Inform. Klaus Moeller (Incident Response Team)
Phone: +49 40 808077-555, Fax: +49 40 808077-556
DFN-CERT Services GmbH, https://www.dfn-cert.de, Phone +49 40 808077-555
Sitz / Register: Hamburg, AG Hamburg, HRB 88805, Ust-IdNr.: DE 232129737
Sachsenstrase 5, 20097 Hamburg/Germany, CEO: Dr. Klaus-Peter Kossakowski
- -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
=============================================================================
FreeBSD-SA-09:13.pipe Security Advisory
The FreeBSD Project
Topic: kqueue pipe race conditions
Category: core
Module: kern
Announced: 2009-10-02
Credits: Przemyslaw Frasunek
Affects: FreeBSD 6.x
Corrected: 2009-10-02 18:09:56 UTC (RELENG_6, 6.4-STABLE)
2009-10-02 18:09:56 UTC (RELENG_6_4, 6.4-RELEASE-p7)
2009-10-02 18:09:56 UTC (RELENG_6_3, 6.3-RELEASE-p13)
For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit <URL:http://security.FreeBSD.org/>.
I. Background
Pipes are a form of inter-process communication (IPC) provided by the
FreeBSD kernel. kqueue is an event management API that applications can
use to monitor pipes and other kernel services.
II. Problem Description
A race condition exists in the pipe close() code relating to kqueues,
causing use-after-free for kernel memory, which may lead to an
exploitable NULL pointer vulnerability in the kernel, kernel memory
corruption, and other unpredictable results.
III. Impact
Successful exploitation of the race condition can lead to local kernel
privilege escalation, kernel data corruption and/or crash.
To exploit this vulnerability, an attacker must be able to run code on
the target system.
IV. Workaround
An errata notice, FreeBSD-EN-09:05.null has been released simultaneously to
this advisory, and contains a kernel patch implementing a workaround for a
more broad class of vulnerabilities. However, prior to those changes, no
workaround is available.
V. Solution
Perform one of the following:
1) Upgrade your vulnerable system to 6-STABLE, or to the RELENG_6_4, or
RELENG_6_3 security branch dated after the correction date.
2) To patch your present system:
The following patches have been verified to apply to FreeBSD 6.3 and 6.4.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch http://security.FreeBSD.org/patches/SA-09:13/pipe.patch
# fetch http://security.FreeBSD.org/patches/SA-09:13/pipe.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.
CVS:
Branch Revision
Path
- - -------------------------------------------------------------------------
RELENG_6
src/sys/kern/kern_event.c 1.93.2.7
src/sys/kern/kern_fork.c 1.252.2.8
src/sys/kern/sys_pipe.c 1.184.2.6
src/sys/sys/event.h 1.32.2.1
src/sys/sys/pipe.h 1.29.2.1
RELENG_6_4
src/UPDATING 1.416.2.40.2.11
src/sys/conf/newvers.sh 1.69.2.18.2.13
src/sys/kern/kern_event.c 1.93.2.6.6.2
src/sys/kern/kern_fork.c 1.252.2.7.4.2
src/sys/kern/sys_pipe.c 1.184.2.4.2.3
src/sys/sys/event.h 1.32.12.2
src/sys/sys/pipe.h 1.29.16.2
RELENG_6_3
src/UPDATING 1.416.2.37.2.18
src/sys/conf/newvers.sh 1.69.2.15.2.17
src/sys/kern/kern_event.c 1.93.2.6.4.1
src/sys/kern/kern_fork.c 1.252.2.7.2.1
src/sys/kern/sys_pipe.c 1.184.2.2.6.3
src/sys/sys/event.h 1.32.10.1
src/sys/sys/pipe.h 1.29.12.1
- - -------------------------------------------------------------------------
Subversion:
Branch/path Revision
- - -------------------------------------------------------------------------
stable/6/ r197715
releng/6.4/ r197715
releng/6.3/ r197715
- - -------------------------------------------------------------------------
VII. References
http://svn.freebsd.org/viewvc/base?view=revision&revision=179243
The latest revision of this advisory is available at
http://security.FreeBSD.org/advisories/FreeBSD-SA-09:13.pipe.asc
- -----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (FreeBSD)
iD8DBQFKxlthFdaIBMps37IRAlk2AJ9mUrNPd1RMztbzO4w7g+AxosqJzgCgmr5l
FKxrbF0G4v9P6SyyfAdVOFY=
=TWhC
- -----END PGP SIGNATURE-----
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.2 (GNU/Linux)
iD8DBQFKyhPSk0kIxZMiiQ8RAo0DAKCogfxLOzCH9GkrbmgvBEhiPM9ZKQCgjvjY
FijaIuJX2eIcZk9keGd6Cik=
=HCJI
-----END PGP SIGNATURE-----
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Search]
