Topic

Updated kernel packages that fix multiple security issues and various bugs
are now available for Red Hat Enterprise Linux 6.

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

This update fixes the following security issues:

• IPv6 fragment identification value generation could allow a remote

attacker to disrupt a target system's networking, preventing legitimate
users from accessing its services. (CVE-2011-2699, Important)

• A signedness issue was found in the Linux kernel's CIFS (Common Internet

File System) implementation. A malicious CIFS 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)

• A flaw was found in the way the Linux kernel handled fragmented IPv6 UDP

datagrams over the bridge with UDP Fragmentation Offload (UFO)
functionality on. A remote attacker could use this flaw to cause a denial
of service. (CVE-2011-4326, Important)

• The way IPv4 and IPv6 protocol sequence numbers and fragment IDs were

generated 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 buffer overflow flaw was found in the Linux kernel's FUSE (Filesystem

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

• A flaw was found in the b43 driver in the Linux kernel. 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 was found in the way CIFS shares with DFS referrals at their root

were handled. An attacker on the local network who is able to deploy a
malicious CIFS server could create a CIFS network share that, when mounted,
would cause the client system to crash. (CVE-2011-3363, Moderate)

• A flaw was found in the way the Linux kernel handled VLAN 0 frames with

the priority tag set. When using certain network drivers, an attacker on
the local network could use this flaw to cause a denial of service.
(CVE-2011-3593, 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)

• A heap overflow flaw was found in the Linux kernel's EFI GUID Partition

Table (GPT) implementation. A local attacker could use this flaw to cause
a denial of service by mounting a disk that contains specially-crafted
partition tables. (CVE-2011-1577, Low)

• The I/O statistics from the taskstats subsystem could be read without

any restrictions. A local, unprivileged user could use this flaw to gather
confidential information, such as the length of a password used in a
process. (CVE-2011-2494, Low)

• It was found that the perf tool, a part of the Linux kernel's Performance

Events implementation, could load its configuration file from the current
working directory. If a local user with access to the perf tool were
tricked into running perf in a directory that contains a specially-crafted
configuration file, it could cause perf to overwrite arbitrary files and
directories accessible to that user. (CVE-2011-2905, Low)

Red Hat would like to thank Fernando Gont for reporting CVE-2011-2699;
Darren Lavender for reporting CVE-2011-3191; Dan Kaminsky for reporting
CVE-2011-3188; Yogesh Sharma for reporting CVE-2011-3363; Gideon Naim for
reporting CVE-2011-3593; Peter Huewe for reporting CVE-2011-1162; Timo
Warns for reporting CVE-2011-1577; and Vasiliy Kulikov of Openwall for
reporting CVE-2011-2494.

This update also fixes various bugs. Documentation for these changes will
be available shortly from the Technical Notes document linked to in the
References section.

Solution

Users should upgrade to these updated packages, which contain
backported patches to correct these issues, and fix the bugs noted in
the Technical Notes. The system must be rebooted for this update to
take effect.

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

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 695976 - CVE-2011-1577 kernel: corrupted GUID partition tables can cause kernel oops
• BZ - 716842 - CVE-2011-2494 kernel: taskstats io infoleak
• BZ - 723429 - CVE-2011-2699 kernel: ipv6: make fragment identifications less predictable
• BZ - 729808 - CVE-2011-2905 kernel: perf tools: may parse user-controlled configuration file
• 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 - 740352 - make guest mode entry to be rcu quiescent state [rhel-6.1.z]
• BZ - 741166 - enclosure fix [rhel-6.1.z]
• BZ - 742846 - CVE-2011-3593 kernel: vlan: fix panic when handling priority tagged frames
• BZ - 743807 - igb: failed to activate WOL on 2nd LAN port on i350 [rhel-6.1.z]
• BZ - 744811 - Non-responsive scsi target leads to excessive scsi recovery and dm-mp failover time [rhel-6.1.z]
• BZ - 748808 - Host got crash when guest running netperf client with UDP_STREAM protocol with IPV6 [rhel-6.1.z]
• BZ - 755584 - CVE-2011-4326 kernel: wrong headroom check in udp6_ufo_fragment()

CVEs

• CVE-2011-1577
• CVE-2011-3188
• CVE-2011-2699
• CVE-2011-3191
• CVE-2011-3593
• CVE-2011-3363
• CVE-2011-2494
• CVE-2011-4326
• CVE-2011-3353
• CVE-2011-1162
• CVE-2011-2905
• CVE-2011-3359

References

• https://access.redhat.com/security/updates/classification/#important
• https://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/6.1_Technical_Notes/kernel.html#RHSA-2011-1465