RHSA-2010:0723 - Security Advisory

Topic

Updated kernel packages that fix multiple 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
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.

This update fixes the following security issues:

• A buffer overflow flaw was found in the ecryptfs_uid_hash() function in

the Linux kernel eCryptfs implementation. On systems that have the eCryptfs
netlink transport (Red Hat Enterprise Linux 5 does) or where the
"/dev/ecryptfs" file has world writable permissions (which it does not, by
default, on Red Hat Enterprise Linux 5), a local, unprivileged user could
use this flaw to cause a denial of service or possibly escalate their
privileges. (CVE-2010-2492, Important)

• A miscalculation of the size of the free space of the initial directory

entry in a directory leaf block was found in the Linux kernel Global File
System 2 (GFS2) implementation. A local, unprivileged user with write
access to a GFS2-mounted file system could perform a rename operation on
that file system to trigger a NULL pointer dereference, possibly resulting
in a denial of service or privilege escalation. (CVE-2010-2798, Important)

• A flaw was found in the Xen hypervisor implementation when running a

system that has an Intel CPU without Extended Page Tables (EPT) support.
While attempting to dump information about a crashing fully-virtualized
guest, the flaw could cause the hypervisor to crash the host as well. A
user with permissions to configure a fully-virtualized guest system could
use this flaw to crash the host. (CVE-2010-2938, Moderate)

• Information leak flaws were found in the Linux kernel's Traffic Control

Unit implementation. A local attacker could use these flaws to cause the
kernel to leak kernel memory to user-space, possibly leading to the
disclosure of sensitive information. (CVE-2010-2942, Moderate)

• A flaw was found in the Linux kernel's XFS file system implementation.

The file handle lookup could return an invalid inode as valid. If an XFS
file system was mounted via NFS (Network File System), a local attacker
could access stale data or overwrite existing data that reused the inodes.
(CVE-2010-2943, Moderate)

• An integer overflow flaw was found in the extent range checking code in

the Linux kernel's ext4 file system implementation. A local, unprivileged
user with write access to an ext4-mounted file system could trigger this
flaw by writing to a file at a very large file offset, resulting in a local
denial of service. (CVE-2010-3015, Moderate)

• An information leak flaw was found in the Linux kernel's USB

implementation. Certain USB errors could result in an uninitialized kernel
buffer being sent to user-space. An attacker with physical access to a
target system could use this flaw to cause an information leak.
(CVE-2010-1083, Low)

Red Hat would like to thank Andre Osterhues for reporting CVE-2010-2492;
Grant Diffey of CenITex for reporting CVE-2010-2798; Toshiyuki Okajima for
reporting CVE-2010-3015; and Marcus Meissner for reporting CVE-2010-1083.

This update also fixes several bugs. Documentation for these bug fixes will
be available shortly from the Technical Notes document linked to in the
References.

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
http://kbase.redhat.com/faq/docs/DOC-11259

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 - 566624 - CVE-2010-1083 kernel: information leak via userspace USB interface
• BZ - 611385 - CVE-2010-2492 kernel: ecryptfs_uid_hash() buffer overflow
• BZ - 620300 - CVE-2010-2798 kernel: gfs2: rename causes kernel panic
• BZ - 620490 - CVE-2010-2938 kernel: guest crashes on non-EPT machines may crash the host as well
• BZ - 620661 - ips driver sleeps while holding spin_lock [rhel-5.5.z]
• BZ - 621940 - Significant MSI performance issue due to redundant interrupt masking [rhel-5.5.z]
• BZ - 623141 - High CPU overhead from mapping/unmapping the zero page [rhel-5.5.z]
• BZ - 623143 - [5u6] Bonding in ALB mode sends ARP in loop [rhel-5.5.z]
• BZ - 624327 - CVE-2010-3015 kernel: integer overflow in ext4_ext_get_blocks()
• BZ - 624365 - cpu flags missing from /proc/cpuinfo [rhel-5.5.z]
• BZ - 624369 - need to backport 2e3219b5c8a2e44e0b83ae6e04f52f20a82ac0f2 [rhel-5.5.z]
• BZ - 624903 - CVE-2010-2942 kernel: net sched: fix some kernel memory leaks
• BZ - 624923 - CVE-2010-2943 kernel: xfs: validate inode numbers in file handles correctly
• BZ - 627194 - dasd: force online does not work. [rhel-5.5.z]
• BZ - 627195 - dasd: allocate fallback cqr for reserve/release [rhel-5.5.z]
• BZ - 629219 - [rhel5.6] XFS incorrectly validates inodes [rhel-5.5.z]
• BZ - 630978 - Detect and recover from cxgb3 adapter parity errors [rhel-5.5.z]

CVEs

• CVE-2010-1083
• CVE-2010-2798
• CVE-2010-3015
• CVE-2010-2943
• CVE-2010-2492
• CVE-2010-2942
• CVE-2010-2938

References

• http://www.redhat.com/security/updates/classification/#important
• http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/5.5_Technical_Notes/kernel.html#id3512212