RHN Errata Alert: Important: kernel security and bug fix update

[Red Hat Network Alert <dev-null@rhn.redhat.com>]

Red Hat Network has determined that the following advisory is applicable to
one or more of the systems you have registered:

Complete information about this errata can be found at the following location:
     https://rhn.redhat.com/rhn/errata/details/Details.do?eid=9303

Security Advisory - RHSA-2009:1550-1
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Summary:
Important: kernel security and bug fix update

Updated kernel packages that fix several security issues and multiple bugs
are now available for Red Hat Enterprise Linux 3.

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

Description:
The kernel packages contain the Linux kernel, the core of any Linux
operating system.

Security fixes:

* when fput() was called to close a socket, the __scm_destroy() function in
the Linux kernel could make indirect recursive calls to itself. This could,
potentially, lead to a denial of service issue. (CVE-2008-5029, Important)

* the sendmsg() function in the Linux kernel did not block during UNIX
socket garbage collection. This could, potentially, lead to a local denial
of service. (CVE-2008-5300, Important)

* the exit_notify() function in the Linux kernel did not properly reset the
exit signal if a process executed a set user ID (setuid) application before
exiting. This could allow a local, unprivileged user to elevate their
privileges. (CVE-2009-1337, Important)

* a flaw was found in the Intel PRO/1000 network driver in the Linux
kernel. Frames with sizes near the MTU of an interface may be split across
multiple hardware receive descriptors. Receipt of such a frame could leak
through a validation check, leading to a corruption of the length check. A
remote attacker could use this flaw to send a specially-crafted packet that
would cause a denial of service or code execution. (CVE-2009-1385,
Important)

* the ADDR_COMPAT_LAYOUT and MMAP_PAGE_ZERO flags were not cleared when a
setuid or setgid program was executed. A local, unprivileged user could use
this flaw to bypass the mmap_min_addr protection mechanism and perform a
NULL pointer dereference attack, or bypass the Address Space Layout
Randomization (ASLR) security feature. (CVE-2009-1895, Important)

* it was discovered that, when executing a new process, the clear_child_tid
pointer in the Linux kernel is not cleared. If this pointer points to a
writable portion of the memory of the new program, the kernel could corrupt
four bytes of memory, possibly leading to a local denial of service or
privilege escalation. (CVE-2009-2848, Important)

* missing initialization flaws were found in getname() implementations in
the IrDA sockets, AppleTalk DDP protocol, NET/ROM protocol, and ROSE
protocol implementations in the Linux kernel. Certain data structures in
these getname() implementations were not initialized properly before being
copied to user-space. These flaws could lead to an information leak.
(CVE-2009-3002, Important)

* a NULL pointer dereference flaw was found in each of the following
functions in the Linux kernel: pipe_read_open(), pipe_write_open(), and
pipe_rdwr_open(). When the mutex lock is not held, the i_pipe pointer could
be released by other processes before it is used to update the pipe's
reader and writer counters. This could lead to a local denial of service or
privilege escalation. (CVE-2009-3547, Important)

Bug fixes:

* this update adds the mmap_min_addr tunable and restriction checks to help
prevent unprivileged users from creating new memory mappings below the
minimum address. This can help prevent the exploitation of NULL pointer
dereference bugs. Note that mmap_min_addr is set to zero (disabled) by
default for backwards compatibility. (BZ#512642)

* a bridge reference count problem in IPv6 has been fixed. (BZ#457010)

* enforce null-termination of user-supplied arguments to setsockopt().
(BZ#505514)

* the gcc flag "-fno-delete-null-pointer-checks" was added to the kernel
build options. This prevents gcc from optimizing out NULL pointer checks
after the first use of a pointer. NULL pointer bugs are often exploited by
attackers. Keeping these checks is a safety measure. (BZ#511185)

* a check has been added to the IPv4 code to make sure that rt is not NULL,
to help prevent future bugs in functions that call ip_append_data() from
being exploitable. (BZ#520300)

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.

References:
http://www.redhat.com/security/updates/classification/#important
http://kbase.redhat.com/faq/docs/DOC-17866
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Taking Action
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You may address the issues outlined in this advisory in two ways:

     - select your server name by clicking on its name from the list
       available at the following location, and then schedule an
       errata update for it:
           https://rhn.redhat.com/rhn/systems/SystemList.do

     - run the Update Agent on each affected server.


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Affected Systems List
---------------------
This Errata Advisory may apply to the systems listed below. If you know that
this errata does not apply to a system listed, it might be possible that the
package profile for that server is out of date. In that case you should refresh 
the system's package profile by running *one* of the following commands as root 
on that system:

 * 'up2date -p' (on Enterprise Linux systems prior to RHEL5)
 * 'rhn-profile-sync' (on Enterprise Linux 5 or later) 

There are 20 affected systems registered in 'Your RHN' (only systems for
which you have explicitly enabled Errata Alerts are shown).

Release   Arch       Profile Name
--------  --------   ------------


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