RHSA-2013:0847 - Security Advisory

Topic

Updated kernel packages that fix one security issue and multiple bugs are
now available for Red Hat Enterprise Linux 5.

The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link 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 issue:

• A flaw was found in the way the Xen hypervisor AMD IOMMU driver handled

interrupt remapping entries. By default, a single interrupt remapping
table is used, and old interrupt remapping entries are not cleared,
potentially allowing a privileged guest user in a guest that has a
passed-through, bus-mastering capable PCI device to inject interrupt
entries into others guests, including the privileged management domain
(Dom0), leading to a denial of service. (CVE-2013-0153, Moderate)

Red Hat would like to thank the Xen project for reporting the CVE-2013-0153
issue.

This update also fixes the following bugs:

• When a process is opening a file over NFSv4, sometimes an OPEN call can

succeed while the following GETATTR operation fails with an NFS4ERR_DELAY
error. The NFSv4 code did not handle such a situation correctly and allowed
an NFSv4 client to attempt to use the buffer that should contain the
GETATTR information. However, the buffer did not contain the valid GETATTR
information, which caused the client to return a "-ENOTDIR" error.
Consequently, the process failed to open the requested file. This update
backports a patch that adds a test condition verifying validity of the
GETATTR information. If the GETATTR information is invalid, it is obtained
later and the process opens the requested file as expected. (BZ#947736)

• Previously, the xdr routines in NFS version 2 and 3 conditionally updated

the res->count variable. Read retry attempts after a short NFS read() call
could fail to update the res->count variable, resulting in truncated read
data being returned. With this update, the res->count variable is updated
unconditionally so this bug can no longer occur. (BZ#952098)

• When handling requests from Intelligent Platform Management Interface

(IPMI) clients, the IPMI driver previously used two different locks for an
IPMI request. If two IPMI clients sent their requests at the same time,
each request could receive one of the locks and then wait for the second
lock to become available. This resulted in a deadlock situation and the
system became unresponsive. The problem could occur more likely in
environments with many IPMI clients. This update modifies the IPMI driver
to handle the received messages using tasklets so the driver now uses a
safe locking technique when handling IPMI requests and the mentioned
deadlock can no longer occur. (BZ#953435)

• Incorrect locking around the cl_state_owners list could cause the NFSv4

state reclaimer thread to enter an infinite loop while holding the Big
Kernel Lock (BLK). As a consequence, the NFSv4 client became unresponsive.
With this update, safe list iteration is used, which prevents the NFSv4
client from hanging in this scenario. (BZ#954296)

Users should upgrade to these updated packages, which contain backported
patches to 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/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 for x86_64 - Extended Update Support 5.9 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.9 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.9 i386
• Red Hat Enterprise Linux Server - AUS 5.9 ia64
• 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 IBM z Systems - Extended Update Support 5.9 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.9 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.9 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.9 i386
• Red Hat Enterprise Linux Server - AUS 5.9 x86_64
• Red Hat Enterprise Linux Server - AUS 5.9 i386

Fixes

• BZ - 910903 - CVE-2013-0153 kernel: xen: interrupt remap entries shared and old ones not cleared on AMD IOMMUs

CVEs

• CVE-2013-0153

References

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