RHSA-2010:0041 - Security Advisory

Topic

Updated kernel-rt packages that fix multiple security issues and several
bugs are now available for Red Hat Enterprise MRG 1.2.

This update has been rated as having important security impact by the Red
Hat Security Response Team.

Description

The kernel-rt packages contain the Linux kernel, the core of any Linux
operating system.

This update fixes the following security issues:

• an array index error was found in the gdth driver in the Linux kernel. A

local user could send a specially-crafted IOCTL request that would cause a
denial of service or, possibly, privilege escalation. (CVE-2009-3080,
Important)

• a flaw was found in the FUSE implementation in the Linux kernel. When a

system is low on memory, fuse_put_request() could dereference an invalid
pointer, possibly leading to a local denial of service or privilege
escalation. (CVE-2009-4021, Important)

• a flaw was found in each of the following Intel PRO/1000 Linux drivers in

the Linux kernel: e1000 and e1000e. A remote attacker using packets larger
than the MTU could bypass the existing fragment check, resulting in
partial, invalid frames being passed to the network stack. These flaws
could also possibly be used to trigger a remote denial of service.
(CVE-2009-4536, CVE-2009-4538, Important)

• a flaw was found in the Realtek r8169 Ethernet driver in the Linux

kernel. Receiving overly-long frames with a certain revision of the network
cards supported by this driver could possibly result in a remote denial of
service. (CVE-2009-4537, Important)

This update also fixes the following bugs:

• the "function tracer" from ftrace could eventually present problems when

a module was unloaded during a tracing session. Some of the related call
site entries for that module were not removed from ftrace's internal lists
and could lead to confusing "oops" error messages. The call site entries
are now removed correctly, and the errors no longer occur. (BZ#537472)

• when using the kernel in tickless (or NOHZ) mode, time was not

accumulated one tick at a time. This created latencies when the accumulated
interval grew large. Time is now accumulated logarithmically and latencies
related to tickless mode no longer occur. (BZ#538370)

• running the "cset set" command was resulting in unsafe access to a

structure that could be concurrently changed. This was eventually causing
the kernel to crash. The operations were repositioned so that they no
longer add locks, to minimize performance penalties. (BZ#541080)

• the function used to calculate system load called different functions to

count the tasks in running and interpretable states. On systems with a
large number of CPUs, this could result in several TLB and cache misses.
These functions have now been combined, and the problem has been
significantly reduced. (BZ#552860)

• when legacy PCI bus checks occurred, an off-by-one error would present.

Scanning 255 PCI buses is now allowed as 0xff is a valid bus, and the error
no longer occurs. (BZ#552874)

• on systems with 8 or more CPUs, an unnecessary anon_vma lock acquisition

in vma_adjust() was causing a decrease in throughput. Code from the
upstream kernel was backported, and the throughput decrease no longer
exists. (BZ#552876)

• the scheduler function double_lock_balance() favors logically lower CPUs.

This could cause logically higher CPUs to be starved if run queues were
under a lot of pressure, resulting in latencies. The algorithm has been
adjusted so that it is fairer, and logically higher CPUs no longer risk
being starved. (BZ#552877)

These updated packages also include other bug fixes. Users are directed to
the Red Hat Enterprise MRG 1.2 Release Notes for information on those
fixes, available shortly from:

http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_MRG/

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 that all previously-released
errata relevant to your system have been applied.

This update is available via 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

Affected Products

• MRG Realtime 1 x86_64
• MRG Realtime 1 i386

Fixes

• BZ - 537472 - ftrace function tracer triggers integrity check failure
• BZ - 538734 - CVE-2009-4021 kernel: fuse: prevent fuse_put_request on invalid pointer
• BZ - 539414 - CVE-2009-3080 kernel: gdth: Prevent negative offsets in ioctl
• BZ - 541080 - MRG Kernel crashes when we run "cset set" command, but the crash is random.
• BZ - 550907 - CVE-2009-4537 kernel: r8169 issue reported at 26c3
• BZ - 551214 - CVE-2009-4538 kernel: e1000e frame fragment issue
• BZ - 552126 - CVE-2009-4536 kernel: e1000 issue reported at 26c3

CVEs

• CVE-2009-4021
• CVE-2009-3080
• CVE-2009-4538
• CVE-2009-4537
• CVE-2009-4536

References

• http://www.redhat.com/security/updates/classification/#important
• http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_MRG/