Synopsis

Important: kernel-rt security and bug fix update

Type/Severity

Security Advisory: Important

Topic

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.

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,
Moderate)

• 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,
Moderate)

• 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.
(BZ#768413)

• 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.

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
https://access.redhat.com/kb/docs/DOC-11259

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.

Affected Products

• MRG Realtime 2 x86_64

Fixes

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

CVEs

• CVE-2011-2723
• CVE-2011-2898
• CVE-2011-3188
• CVE-2011-3191
• CVE-2011-3363
• CVE-2011-2494
• CVE-2011-4326
• CVE-2011-3353
• CVE-2011-1162
• CVE-2011-3359
• CVE-2011-4110
• CVE-2011-3637
• CVE-2011-4132
• CVE-2011-4081

References