RHSA-2009:1081 - Security Advisory

Topic

Updated kernel-rt packages that fix several security issues and various
bugs are now available for Red Hat Enterprise MRG 1.1.3.

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.

These updated packages fix the following security issues:

• a buffer overflow flaw was found in the CIFSTCon() function of the Linux

kernel Common Internet File System (CIFS) implementation. When mounting a
CIFS share, a malicious server could send an overly-long string to the
client, possibly leading to a denial of service or privilege escalation on
the client mounting the CIFS share. (CVE-2009-1439, Important)

• the Linux kernel Network File System daemon (nfsd) implementation did not

drop the CAP_MKNOD capability when handling requests from local,
unprivileged users. This flaw could possibly lead to an information leak or
privilege escalation. (CVE-2009-1072, Moderate)

• a deficiency was found in the Linux kernel signals implementation. The

kill_something_info() function did not check if a process was outside the
caller's namespace before sending the kill signal, making it possible to
kill processes in all process ID (PID) namespaces, breaking PID namespace
isolation. (CVE-2009-1338, Moderate)

• a flaw was found in the AGPGART driver. The agp_generic_alloc_page() and

agp_generic_alloc_pages() functions did not zero out the memory pages they
allocate, which may later be available to user-space processes. This flaw
could possibly lead to an information leak. (CVE-2009-1192, Low)

These updated packages also fix the following bugs:

• the "-fwrapv" flag was added to the gcc build options to prevent gcc from

optimizing away wrapping arithmetic, as optimizing away wrapping may lead
to unexpected results. (BZ#491264)

• the bnx2x driver may have failed when highly-stressed by network

stress-tests, resulting in network access being unavailable. This driver
has been updated to resolve this issue. (BZ#495472)

• the file system mask, which lists capabilities for users with a file

system user ID (fsuid) of 0, was missing the CAP_MKNOD and
CAP_LINUX_IMMUTABLE capabilities. This could, potentially, allow users with
an fsuid other than 0 to perform actions on some file system types that
would otherwise be prevented. This update adds these capabilities.
(BZ#497047)

• "/proc/[pid]/maps" and "/proc/[pid]/smaps" can only be read by processes

able to use the ptrace() call on a given process; however, certain
information from "/proc/[pid]/stat" and "/proc/[pid]/wchan" could be used
to reconstruct memory maps, making it possible to bypass the Address Space
Layout Randomization (ASLR) security feature. This update addresses this
issue. (BZ#499550)

• the get_random_int() function returned the same number until the jiffies

counter (which ticks at a clock interrupt frequency) or process ID (PID)
changed, making it possible to predict the random numbers. This may have
helped to bypass the ASLR security feature. With this update,
get_random_int() is more random and no longer uses a common seed value.
This reduces the possibility of predicting the values get_random_int()
returns. (BZ#499787)

All Red Hat Enterprise MRG users should upgrade to these updated packages,
which contain backported patches to resolve these issues. Note: 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 - 491264 - kernel-rt should be built with -fwrapv [mrg-1]
• BZ - 491572 - CVE-2009-1072 kernel: nfsd should drop CAP_MKNOD for non-root
• BZ - 494275 - CVE-2009-1439 kernel: cifs: memory overwrite when saving nativeFileSystem field during mount
• BZ - 495472 - [Broadcom10gb] daEth stress breaks bnx2x driver in MRG1.1
• BZ - 496031 - CVE-2009-1338 kernel: 'kill sig -1' must only apply to caller's pid namespace
• BZ - 497020 - CVE-2009-1192 kernel: agp: zero pages before sending to userspace
• BZ - 497047 - kernel: add some long-missing capabilities to fs_mask
• BZ - 499550 - kernel: proc: avoid information leaks to non-privileged processes [mrg-1]
• BZ - 499787 - kernel: random: make get_random_int() more random [mrg-1]

CVEs

• CVE-2009-3238
• CVE-2009-1338
• CVE-2009-1072
• CVE-2009-1192
• CVE-2009-1439

References

• http://www.redhat.com/security/updates/classification/#important