RHSA-2012:1540 - Security Advisory

Topic

Updated kernel packages that fix multiple security issues, two bugs, and
add two enhancements are now available for Red Hat Enterprise Linux 5.

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

These packages contain the Linux kernel.

Security fixes:

• A race condition in the way asynchronous I/O and fallocate() interacted

when using ext4 could allow a local, unprivileged user to obtain random
data from a deleted file. (CVE-2012-4508, Important)

• A flaw in the way the Xen hypervisor implementation range checked guest

provided addresses in the XENMEM_exchange hypercall could allow a
malicious, para-virtualized guest administrator to crash the hypervisor or,
potentially, escalate their privileges, allowing them to execute arbitrary
code at the hypervisor level. (CVE-2012-5513, Important)

• A flaw in the Reliable Datagram Sockets (RDS) protocol implementation

could allow a local, unprivileged user to cause a denial of service.
(CVE-2012-2372, Moderate)

• A race condition in the way access to inet->opt ip_options was

synchronized in the Linux kernel's TCP/IP protocol suite implementation.
Depending on the network facing applications running on the system, a
remote attacker could possibly trigger this flaw to cause a denial of
service. A local, unprivileged user could use this flaw to cause a denial
of service regardless of the applications the system runs. (CVE-2012-3552,
Moderate)

• The Xen hypervisor implementation did not properly restrict the period

values used to initialize per VCPU periodic timers. A privileged guest user
could cause an infinite loop on the physical CPU. If the watchdog were
enabled, it would detect said loop and panic the host system.
(CVE-2012-4535, Moderate)

• A flaw in the way the Xen hypervisor implementation handled

set_p2m_entry() error conditions could allow a privileged,
fully-virtualized guest user to crash the hypervisor. (CVE-2012-4537,
Moderate)

Red Hat would like to thank Theodore Ts'o for reporting CVE-2012-4508; the
Xen project for reporting CVE-2012-5513, CVE-2012-4535, and CVE-2012-4537;
and Hafid Lin for reporting CVE-2012-3552. Upstream acknowledges Dmitry
Monakhov as the original reporter of CVE-2012-4508. CVE-2012-2372 was
discovered by Li Honggang of Red Hat.

Bug fixes:

• Previously, the interrupt handlers of the qla2xxx driver could clear

pending interrupts right after the IRQ lines were attached during system
start-up. Consequently, the kernel could miss the interrupt that reported
completion of the link initialization, and the qla2xxx driver then failed
to detect all attached LUNs. With this update, the qla2xxx driver has been
modified to no longer clear interrupt bits after attaching the IRQ lines.
The driver now correctly detects all attached LUNs as expected. (BZ#870118)

• The Ethernet channel bonding driver reported the MII (Media Independent

Interface) status of the bond interface in 802.3ad mode as being up even
though the MII status of all of the slave devices was down. This could pose
a problem if the MII status of the bond interface was used to determine if
failover should occur. With this update, the agg_device_up() function has
been added to the bonding driver, which allows the driver to report the
link status of the bond interface correctly, that is, down when all of its
slaves are down, in the 802.3ad mode. (BZ#877943)

Enhancements:

• This update backports several changes from the latest upstream version of

the bnx2x driver. The most important change, the remote-fault link
detection feature, allows the driver to periodically scan the physical link
layer for remote faults. If the physical link appears to be up and a fault
is detected, the driver indicates that the link is down. When the fault is
cleared, the driver indicates that the link is up again. (BZ#870120)

• The INET socket interface has been modified to send a warning message

when the ip_options structure is allocated directly by a third-party module
using the kmalloc() function. (BZ#874973)

Users should upgrade to these updated packages, which contain backported
patches to correct these issues and add these enhancements. 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/knowledge/articles/11258

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 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

• BZ - 822754 - CVE-2012-2372 kernel: rds-ping cause kernel panic
• BZ - 853465 - CVE-2012-3552 kernel: net: slab corruption due to improper synchronization around inet->opt
• BZ - 869904 - CVE-2012-4508 kernel: ext4: AIO vs fallocate stale data exposure
• BZ - 870086 - CVE-2012-4535 kernel: xen: VCPU timer overflow leads to PCPU deadlock and host death-by-watchdog
• BZ - 870101 - CVE-2012-4537 kernel: xen: Memory mapping failure can crash Xen
• BZ - 874973 - net: WARN if struct ip_options was allocated directly by kmalloc [rhel-5.8.z]
• BZ - 877391 - CVE-2012-5513 kernel: xen: XENMEM_exchange may overwrite hypervisor memory

CVEs

• CVE-2012-2372
• CVE-2012-3552
• CVE-2012-5513
• CVE-2012-4537
• CVE-2012-4535
• CVE-2012-4508

References

• https://access.redhat.com/security/updates/classification/#important