RHSA-2015:0783 - Security Advisory

Topic

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

Red Hat Product Security 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.

• It was found that the Linux kernel's Infiniband subsystem did not

properly sanitize input parameters while registering memory regions from
user space via the (u)verbs API. A local user with access to a
/dev/infiniband/uverbsX device could use this flaw to crash the system or,
potentially, escalate their privileges on the system. (CVE-2014-8159,
Important)

• An insufficient bound checking flaw was found in the Xen hypervisor's

implementation of acceleration support for the "REP MOVS" instructions.
A privileged HVM guest user could potentially use this flaw to crash the
host. (CVE-2014-8867, Important)

Red Hat would like to thank Mellanox for reporting CVE-2014-8159, and the
Xen project for reporting CVE-2014-8867.

This update also fixes the following bugs:

• Under memory pressure, cached data was previously flushed to the backing

server using the PID of the thread responsible for flushing the data in the
Server Message Block (SMB) headers instead of the PID of the thread which
actually wrote the data. As a consequence, when a file was locked by the
writing thread prior to writing, the server considered writes by the thread
flushing the pagecache as being a separate process from writing to a locked
file, and thus rejected the writes. In addition, the data to be written was
discarded. This update ensures that the correct PID is sent to the server,
and data corruption is avoided when data is being written from a client
under memory pressure. (BZ#1169304)

• This update adds support for new cryptographic hardware in toleration

mode for IBM System z. (BZ#1182522)

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.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

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 - 1164255 - CVE-2014-8867 xen: Insufficient bounding of "REP MOVS" to MMIO emulated inside the hypervisor (xsa112)
• BZ - 1181166 - CVE-2014-8159 kernel: infiniband: uverbs: unprotected physical memory access

CVEs

• CVE-2014-8159
• CVE-2014-8867

References

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