Important: kernel (SL6)

Synopsis: Important: kernel security and bug fix update
Issue Date: 2011-11-22
CVE Numbers: CVE-2011-1577

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.


– Scientific Linux Development Team