RHSA-2014:0926 - Security Advisory

Topic

Updated kernel packages that fix two security issues and several 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. 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.

• A NULL pointer dereference flaw was found in the rds_iw_laddr_check()

function in the Linux kernel's implementation of Reliable Datagram Sockets
(RDS). A local, unprivileged user could use this flaw to crash the system.
(CVE-2014-2678, Moderate)

• It was found that the Xen hypervisor implementation did not properly

clean memory pages previously allocated by the hypervisor. A privileged
guest user could potentially use this flaw to read data relating to other
guests or the hypervisor itself. (CVE-2014-4021, Moderate)

Red Hat would like to thank the Xen project for reporting CVE-2014-4021.
Upstream acknowledges Jan Beulich as the original reporter.

This update also fixes the following bugs:

• A bug in the journaling block device (jbd and jbd2) code could, under

certain circumstances, trigger a BUG_ON() assertion and result in a kernel
oops. This happened when an application performed an extensive number of
commits to the journal of the ext3 file system and there was no currently
active transaction while synchronizing the file's in-core state. This
problem has been resolved by correcting respective test conditions in the
jbd and jbd2 code. (BZ#1097528)

• After a statically defined gateway became unreachable and its

corresponding neighbor entry entered a FAILED state, the gateway stayed in
the FAILED state even after it became reachable again. As a consequence,
traffic was not routed through that gateway. This update allows probing
such a gateway automatically so that the traffic can be routed through
this gateway again once it becomes reachable. (BZ#1106354)

• Due to an incorrect condition check in the IPv6 code, the ipv6 driver

was unable to correctly assemble incoming packet fragments, which resulted
in a high IPv6 packet loss rate. This update fixes the said check for a
fragment overlap and ensures that incoming IPv6 packet fragments are now
processed as expected. (BZ#1107932)

• Recent changes in the d_splice_alias() function introduced a bug that

allowed d_splice_alias() to return a dentry from a different directory
than the directory being looked up. As a consequence in cluster
environment, a kernel panic could be triggered when a directory was being
removed while a concurrent cross-directory operation was performed on this
directory on another cluster node. This update avoids the kernel panic in
this situation by correcting the search logic in the d_splice_alias()
function so that the function can no longer return a dentry from an
incorrect directory. (BZ#1109720)

• The NFSv4 server did not handle multiple OPEN operations to the same file

separately, which could cause the NFSv4 client to repeatedly send CLOSE
requests with the same state ID, even though the NFS server rejected the
request with an NFS4ERR_OLD_STATEID (10024) error code. This update
ensures that the NFSv4 client no longer re-sends the same CLOSE request
after receiving NFS4ERR_OLD_STATEID. (BZ#1113468)

All kernel users are advised to 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/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 - 1083274 - CVE-2014-2678 kernel: net: rds: dereference of a NULL device in rds_iw_laddr_check()
• BZ - 1103646 - CVE-2014-4021 xen: Hypervisor heap contents leaked to guests (xsa-100)

CVEs

• CVE-2014-2678
• CVE-2014-4021

References

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