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Category:   OS (Linux)  >   Linux Kernel Vendors:
(Red Hat Issues Fix) Linux Kernel Journaling Block Device Input Validation Flaw Lets Local Users Deny Service
SecurityTracker Alert ID:  1026502
SecurityTracker URL:
CVE Reference:   CVE-2011-4132   (Links to External Site)
Date:  Jan 11 2012
Impact:   Denial of service via local system
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): RHEL 6
Description:   A vulnerability was reported in the Linux Kernel. A local user can cause denial of service conditions.

The kernel's Journaling Block Device (JBD) code does not properly validate block values. A local user can mount a specially crafted ext3 or ext4 image to cause the target system to crash.

Impact:   A local user can cause the target user to crash.
Solution:   Red Hat has issued a fix.

The Red Hat advisory is available at:

Vendor URL: (Links to External Site)
Cause:   Input validation error, State error

Message History:   This archive entry is a follow-up to the message listed below.
Nov 14 2011 Linux Kernel Journaling Block Device Input Validation Flaw Lets Local Users Deny Service

 Source Message Contents

Subject:  [RHSA-2012:0010-01] Important: kernel-rt security and bug fix update

Hash: SHA1

                   Red Hat Security Advisory

Synopsis:          Important: kernel-rt security and bug fix update
Advisory ID:       RHSA-2012:0010-01
Product:           Red Hat Enterprise MRG for RHEL-6
Advisory URL:
Issue date:        2012-01-10
CVE Names:         CVE-2011-1162 CVE-2011-2494 CVE-2011-2723 
                   CVE-2011-2898 CVE-2011-3188 CVE-2011-3191 
                   CVE-2011-3353 CVE-2011-3359 CVE-2011-3363 
                   CVE-2011-3637 CVE-2011-4081 CVE-2011-4110 
                   CVE-2011-4132 CVE-2011-4326 

1. Summary:

Updated kernel-rt packages that fix several security issues and two bugs
are now available for Red Hat Enterprise MRG 2.0.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

2. Relevant releases/architectures:

MRG Realtime for RHEL 6 Server v.2 - noarch, x86_64

3. Description:

The kernel-rt packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issues:

* A malicious CIFS (Common Internet File System) server could send a
specially-crafted response to a directory read request that would result in
a denial of service or privilege escalation on a system that has a CIFS
share mounted. (CVE-2011-3191, Important)

* The way fragmented IPv6 UDP datagrams over the bridge with UDP
Fragmentation Offload (UFO) functionality on were handled could allow a
remote attacker to cause a denial of service. (CVE-2011-4326, Important)

* GRO (Generic Receive Offload) fields could be left in an inconsistent
state. An attacker on the local network could use this flaw to cause a
denial of service. GRO is enabled by default in all network drivers that
support it. (CVE-2011-2723, Moderate)

* IPv4 and IPv6 protocol sequence number and fragment ID generation could
allow a man-in-the-middle attacker to inject packets and possibly hijack
connections. Protocol sequence numbers and fragment IDs are now more
random. (CVE-2011-3188, Moderate)

* A flaw in the FUSE (Filesystem in Userspace) implementation could allow
a local user in the fuse group who has access to mount a FUSE file system
to cause a denial of service. (CVE-2011-3353, Moderate)

* A flaw in the b43 driver. If a system had an active wireless interface
that uses the b43 driver, an attacker able to send a specially-crafted
frame to that interface could cause a denial of service. (CVE-2011-3359,

* A flaw in the way CIFS shares with DFS referrals at their root were
handled could allow an attacker on the local network, who is able to deploy
a malicious CIFS server, to create a CIFS network share that, when mounted,
would cause the client system to crash. (CVE-2011-3363, Moderate)

* A flaw in the m_stop() implementation could allow a local, unprivileged
user to trigger a denial of service. (CVE-2011-3637, Moderate)

* Flaws in ghash_update() and ghash_final() could allow a local,
unprivileged user to cause a denial of service. (CVE-2011-4081, Moderate)

* A flaw in the key management facility could allow a local, unprivileged
user to cause a denial of service via the keyctl utility. (CVE-2011-4110,

* A flaw in the Journaling Block Device (JBD) could allow a local attacker
to crash the system by mounting a specially-crafted ext3 or ext4 disk.
(CVE-2011-4132, Moderate)

* A flaw in the way memory containing security-related data was handled in
tpm_read() could allow a local, unprivileged user to read the results of a
previously run TPM command. (CVE-2011-1162, Low)

* I/O statistics from the taskstats subsystem could be read without any
restrictions, which could allow a local, unprivileged user to gather
confidential information, such as the length of a password used in a
process. (CVE-2011-2494, Low)

* Flaws in tpacket_rcv() and packet_recvmsg() could allow a local,
unprivileged user to leak information to user-space. (CVE-2011-2898, Low)

Red Hat would like to thank Darren Lavender for reporting CVE-2011-3191;
Brent Meshier for reporting CVE-2011-2723; Dan Kaminsky for reporting
CVE-2011-3188; Yogesh Sharma for reporting CVE-2011-3363; Nick Bowler for
reporting CVE-2011-4081; Peter Huewe for reporting CVE-2011-1162; and
Vasiliy Kulikov of Openwall for reporting CVE-2011-2494.

This update also fixes the following bugs:

* Previously, a mismatch in the build-id of the kernel-rt and the one in
the related debuginfo package caused failures in SystemTap and perf.

* IBM x3650m3 systems were not able to boot the MRG Realtime kernel because
they require a pmcraid driver that was not available. The pmcraid driver is
included in this update. (BZ#753992)

Users should upgrade to these updated packages, which correct these issues.
The system must be rebooted for this update to take effect.

4. Solution:

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at

To install kernel packages manually, use "rpm -ivh [package]". Do not
use "rpm -Uvh" as that will remove the running kernel binaries from
your system. You may use "rpm -e" to remove old kernels after
determining that the new kernel functions properly on your system.

5. Bugs fixed (

716842 - CVE-2011-2494 kernel: taskstats io infoleak
726552 - CVE-2011-2723 kernel: gro: only reset frag0 when skb can be pulled
728023 - CVE-2011-2898 kernel: af_packet: infoleak
732629 - CVE-2011-1162 kernel: tpm: infoleak
732658 - CVE-2011-3188 kernel: net: improve sequence number generation
732869 - CVE-2011-3191 kernel: cifs: signedness issue in CIFSFindNext()
736761 - CVE-2011-3353 kernel: fuse: check size of FUSE_NOTIFY_INVAL_ENTRY message
738202 - CVE-2011-3359 kernel: b43: allocate receive buffers big enough for max frame len + offset
738291 - CVE-2011-3363 kernel: cifs: always do is_path_accessible check in cifs_mount
747848 - CVE-2011-3637 kernel: proc: fix oops on invalid /proc/<pid>/maps access
749475 - CVE-2011-4081 kernel: crypto: ghash: null pointer deref if no key is set
751297 - CVE-2011-4110 kernel: keys: NULL pointer deref in the user-defined key type
753341 - CVE-2011-4132 kernel: jbd/jbd2: invalid value of first log block leads to oops
755584 - CVE-2011-4326 kernel: wrong headroom check in udp6_ufo_fragment()

6. Package List:

MRG Realtime for RHEL 6 Server v.2:




These packages are GPG signed by Red Hat for security.  Our key and 
details on how to verify the signature are available from

7. References:

8. Contact:

The Red Hat security contact is <>.  More contact
details at

Copyright 2012 Red Hat, Inc.
Version: GnuPG v1.4.4 (GNU/Linux)


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