FreeBSD kqueue Pipe Race Condition Lets Local Users Gain Elevated Privileges
|
|
SecurityTracker Alert ID: 1022982
|
|
SecurityTracker URL: http://securitytracker.com/id?1022982
|
|
CVE Reference: CVE-2009-3527
(Links to External Site)
|
Updated: Oct 14 2009
|
Original Entry Date: Oct 2 2009
|
Impact: Execution of arbitrary code via local system, Root access via local system
|
Fix Available: Yes
Vendor Confirmed: Yes
|
Advisory: FreeBSD Security Advisory
|
Version(s): 6.x
|
Description: A vulnerability was reported in the FreeBSD Kernel. A local user can obtain elevated privileges on the target system.
A local user can exploit a race condition in the kqueue event management API code to trigger a use-after-free memory error. This
may result in a null pointer dereference and arbitrary code execution.
Przemyslaw Frasunek reported this vulnerability.
|
Impact: A local user can obtain elevated privileges on the target system.
|
Solution: The vendor has issued a fix and has provided the following solution instructions [quoted].
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.
The vendor's
advisory is available at:
http://security.FreeBSD.org/advisories/FreeBSD-SA-09:13.pipe.asc
|
Vendor URL: security.FreeBSD.org/advisories/FreeBSD-SA-09:13.pipe.asc (Links to External Site)
|
Cause: Access control error
|
Underlying OS: UNIX (FreeBSD)
|
Reported By: FreeBSD Security Advisories <security-advisories@freebsd.org>
|
Message History:
None.
|
Source Message Contents
|
Date: Fri, 2 Oct 2009 20:11:57 GMT
From: FreeBSD Security Advisories <security-advisories@freebsd.org>
Subject: FreeBSD Security Advisory FreeBSD-SA-09:13.pipe
|
-----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-----
_______________________________________________
freebsd-security-notifications@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-security-notifications
To unsubscribe, send any mail to "freebsd-security-notifications-unsubscribe@freebsd.org"
|
|
