7.8 - RHSA-2012:0007

Problem Description:

Updated kernel packages that fix multiple security issues, several bugs, and add one enhancement are now available for Red Hat Enterprise Linux 5.

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.

2. Relevant releases/architectures:

Red Hat Enterprise Linux (v. 5 server) - i386, ia64, noarch, ppc, s390x, x86_64 Red Hat Enterprise Linux Desktop (v. 5 client) - i386, noarch, x86_64

3. Description:

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

This update fixes the following security issues:

* A buffer overflow flaw was found in the way the Linux kernel's XFS file system implementation handled links with overly long path names. A local, unprivileged user could use this flaw to cause a denial of service or escalate their privileges by mounting a specially-crafted disk. (CVE-2011-4077, Important)

* The fix for CVE-2011-2482 provided by RHSA-2011:1212 introduced a regression: on systems that do not have Security-Enhanced Linux (SELinux) in Enforcing mode, a socket lock race could occur between sctp_rcv() and sctp_accept(). A remote attacker could use this flaw to cause a denial of service. By default, SELinux runs in Enforcing mode on Red Hat Enterprise Linux 5. (CVE-2011-4348, Important)

* The proc file system could allow a local, unprivileged user to obtain sensitive information or possibly cause integrity issues. (CVE-2011-1020, Moderate)

* A missing validation flaw was found in the Linux kernel's m_stop() implementation. A local, unprivileged user could use this flaw to trigger a denial of service. (CVE-2011-3637, Moderate)

* A flaw was found in the Linux kernel's Journaling Block Device (JBD). A local attacker could use this flaw to crash the system by mounting a specially-crafted ext3 or ext4 disk. (CVE-2011-4132, Moderate)

* A flaw was found in the Linux kernel's encode_share_access() implementation. A local, unprivileged user could use this flaw to trigger a denial of service by creating a regular file on an NFSv4 (Network File System version 4) file system via mknod(). (CVE-2011-4324, Moderate)

* A flaw was found in the Linux kernel's NFS implementation. A local, unprivileged user could use this flaw to cause a denial of service. (CVE-2011-4325, Moderate)

* A missing boundary check was found in the Linux kernel's HFS file system implementation. A local attacker could use this flaw to cause a denial of service or escalate their privileges by mounting a specially-crafted disk. (CVE-2011-4330, Moderate)

Red Hat would like to thank Kees Cook for reporting CVE-2011-1020, and Clement Lecigne for reporting CVE-2011-4330.

This update also fixes several bugs and adds one enhancement. 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 contain backported patches to correct these issues, and fix the bugs and add the enhancement noted in the Technical Notes. The system must be rebooted for this update to take effect.

4. 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/kb/docs/DOC-11259

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.

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

680358 - CVE-2011-1020 kernel: no access restrictions of /proc/pid/* after setuid program exec 747848 - CVE-2011-3637 kernel: proc: fix oops on invalid /proc//maps access 749156 - CVE-2011-4077 kernel: xfs: potential buffer overflow in xfs_readlink() 753341 - CVE-2011-4132 kernel: jbd/jbd2: invalid value of first log block leads to oops 755431 - CVE-2011-4330 kernel: hfs: add sanity check for file name length 755440 - CVE-2011-4324 kernel: nfsv4: mknod(2) DoS 755455 - CVE-2011-4325 kernel: nfs: diotest4 from LTP crash client null pointer deref 757143 - CVE-2011-4348 kernel: incomplete fix for CVE-2011-2482