RHSA-2012:1491 - Security Advisory

Topic

Updated kernel-rt packages that fix several security issues and multiple
bugs are now available for Red Hat Enterprise MRG 2.2.

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

This update fixes the following security issues:

• A flaw was found in the way Netlink messages without SCM_CREDENTIALS

(used for authentication) data set were handled. When not explicitly set,
the data was sent but with all values set to 0, including the process ID
and user ID, causing the Netlink message to appear as if it were sent with
root privileges. A local, unprivileged user could use this flaw to send
spoofed Netlink messages to an application, possibly resulting in the
application performing privileged operations if it relied on
SCM_CREDENTIALS data for the authentication of Netlink messages.
(CVE-2012-3520, Important)

• A race condition was found in the way asynchronous I/O and fallocate()

interacted when using the ext4 file system. A local, unprivileged user
could use this flaw to expose random data from an extent whose data blocks
have not yet been written, and thus contain data from a deleted file.
(CVE-2012-4508, Important)

• A use-after-free flaw was found in the Linux kernel's memory management

subsystem in the way quota handling for huge pages was performed. A local,
unprivileged user could use this flaw to cause a denial of service or,
potentially, escalate their privileges. (CVE-2012-2133, Moderate)

• A use-after-free flaw was found in the madvise() system call

implementation in the Linux kernel. A local, unprivileged user could use
this flaw to cause a denial of service or, potentially, escalate their
privileges. (CVE-2012-3511, Moderate)

• A divide-by-zero flaw was found in the TCP Illinois congestion control

algorithm implementation in the Linux kernel. If the TCP Illinois
congestion control algorithm were in use (the sysctl
net.ipv4.tcp_congestion_control variable set to "illinois"), a local,
unprivileged user could trigger this flaw and cause a denial of service.
(CVE-2012-4565, Moderate)

• An information leak flaw was found in the uname() system call

implementation in the Linux kernel. A local, unprivileged user could use
this flaw to leak kernel stack memory to user-space by setting the UNAME26
personality and then calling the uname() system call. (CVE-2012-0957, Low)

• Buffer overflow flaws were found in the udf_load_logicalvol() function in

the Universal Disk Format (UDF) file system implementation in the Linux
kernel. An attacker with physical access to a system could use these flaws
to cause a denial of service or escalate their privileges. (CVE-2012-3400,
Low)

• A flaw was found in the way the msg_namelen variable in the rds_recvmsg()

function of the Linux kernel's Reliable Datagram Sockets (RDS) protocol
implementation was initialized. A local, unprivileged user could use this
flaw to leak kernel stack memory to user-space. (CVE-2012-3430, Low)

Red Hat would like to thank Pablo Neira Ayuso for reporting CVE-2012-3520;
Theodore Ts'o for reporting CVE-2012-4508; Shachar Raindel for reporting
CVE-2012-2133; and Kees Cook for reporting CVE-2012-0957. Upstream
acknowledges Dmitry Monakhov as the original reporter of CVE-2012-4508. The
CVE-2012-4565 issue was discovered by Rodrigo Freire of Red Hat, and the
CVE-2012-3430 issue was discovered by the Red Hat InfiniBand team.

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

Users should upgrade to these updated packages, which upgrade the kernel-rt
kernel to version kernel-rt-3.2.33-rt50, and 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
https://access.redhat.com/knowledge/articles/11258

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

• MRG Realtime 2 x86_64

Fixes

• BZ - 817430 - CVE-2012-2133 kernel: use after free bug in "quota" handling
• BZ - 820039 - CVE-2012-3430 kernel: recv{from,msg}() on an rds socket can leak kernel memory
• BZ - 843130 - RFE kernel: net: mitigate blind reset attacks using RST and SYN bits
• BZ - 843139 - CVE-2012-3400 kernel: udf: buffer overflow when parsing sparing table
• BZ - 849734 - CVE-2012-3511 kernel: mm: use-after-free in madvise_remove()
• BZ - 850449 - CVE-2012-3520 kernel: af_netlink: invalid handling of SCM_CREDENTIALS passing
• BZ - 856243 - kernel-rt-debug potential deadlock
• BZ - 859226 - iptables and other tools unable to log to rsyslog
• BZ - 862877 - CVE-2012-0957 kernel: uts: stack memory leak in UNAME26
• BZ - 864568 - Rebase MRG Realtime kernel to latest upstream 3.2 stable RT release
• BZ - 869904 - CVE-2012-4508 kernel: ext4: AIO vs fallocate stale data exposure
• BZ - 871848 - CVE-2012-4565 kernel: net: divide by zero in tcp algorithm illinois

CVEs

• CVE-2012-3430
• CVE-2012-3511
• CVE-2012-2133
• CVE-2012-3400
• CVE-2012-0957
• CVE-2012-4565
• CVE-2012-3520
• CVE-2012-4508

References

• https://access.redhat.com/security/updates/classification/#important
• https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_MRG/2/html/Technical_Notes/sec-Red_Hat_Enterprise_Linux_6.html#RHSA-2012-1491