10 - RHSA-2010:0041

Problem Description:

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.

2. Relevant releases/architectures:

MRG Realtime for RHEL 5 Server - i386, noarch, x86_64

3. 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.

4. 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

5. Bugs fixed (http://bugzilla.redhat.com/):

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