The kernel packages contain the Linux kernel, the core of any Linux operating system. It was found that the
data_len parameter of the
sock_alloc_send_pskb() function in the networking implementation was not validated before use. A local user with access to a TUN/TAP virtual interface could use this flaw to crash the system or, potentially, escalate their privileges. Note that unprivileged users cannot access TUN/TAP devices until the root user grants them access.
Updated packages are available from ftp.redhat.com.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ===================================================================== Red Hat Security Advisory Synopsis: Important: kernel security and bug fix update Advisory ID: RHSA-2012:1087-01 Product: Red Hat Enterprise Linux Advisory URL: https://rhn.redhat.com/errata/RHSA-2012-1087.html Issue date: 2012-07-17 CVE Names: CVE-2012-2136 ===================================================================== 1. Summary: Updated kernel packages that fix one security issue and multiple bugs are now available for Red Hat Enterprise Linux 5.6 Extended Update Support. The Red Hat Security Response Team has rated this update as having important security impact. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available from the CVE link in the References section. 2. Relevant releases/architectures: Red Hat Enterprise Linux EUS (v. 5.6 server) - i386, ia64, noarch, ppc, s390x, x86_64 3. Description: The kernel packages contain the Linux kernel, the core of any Linux operating system. This update fixes the following security issue: * It was found that the data_len parameter of the sock_alloc_send_pskb() function in the Linux kernel's networking implementation was not validated before use. A local user with access to a TUN/TAP virtual interface could use this flaw to crash the system or, potentially, escalate their privileges. Note that unprivileged users cannot access TUN/TAP devices until the root user grants them access. (CVE-2012-2136, Important) This update also fixes the following bugs: * An insufficiently designed calculation in the CPU accelerator in the previous kernel caused an arithmetic overflow in the sched_clock() function when system uptime exceeded 208.5 days. This overflow led to a kernel panic on the systems using the Time Stamp Counter (TSC) or Virtual Machine Interface (VMI) clock source. This update corrects the described calculation so that this arithmetic overflow and kernel panic can no longer occur under these circumstances. (BZ#825981, BZ#835449) * Previously, a race condition between the journal_write_metadata_buffer() and jbd_unlock_bh_state() functions could occur. Consequently, another thread could call the get_write_access() function on the buffer head and cause the wrong data to be written into the journal. If the system terminated unexpectedly or was shut down incorrectly, subsequent file system journal replay could result in file system corruption. This update fixes the race condition and the file system corruption no longer occurs in the described scenario. (BZ#833764) * When the kvmclock initialization was used in a guest, it could write to the Time Stamp Counter (TSC) and, under certain circumstances, could cause the kernel to become unresponsive on boot. With this update, TSC synchronization, which is unnecessary due to kvmclock, has been disabled, thus fixing this bug. (BZ#834557) 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 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. 5. Bugs fixed (http://bugzilla.redhat.com/): 816289 - CVE-2012-2136 kernel: net: insufficient data_len validation in sock_alloc_send_pskb() 6. Package List: Red Hat Enterprise Linux EUS (v. 5.6 server): Source: kernel-2.6.18-238.40.1.el5.src.rpm i386: kernel-2.6.18-238.40.1.el5.i686.rpm kernel-PAE-2.6.18-238.40.1.el5.i686.rpm kernel-PAE-debuginfo-2.6.18-238.40.1.el5.i686.rpm kernel-PAE-devel-2.6.18-238.40.1.el5.i686.rpm kernel-debug-2.6.18-238.40.1.el5.i686.rpm kernel-debug-debuginfo-2.6.18-238.40.1.el5.i686.rpm kernel-debug-devel-2.6.18-238.40.1.el5.i686.rpm kernel-debuginfo-2.6.18-238.40.1.el5.i686.rpm kernel-debuginfo-common-2.6.18-238.40.1.el5.i686.rpm kernel-devel-2.6.18-238.40.1.el5.i686.rpm kernel-headers-2.6.18-238.40.1.el5.i386.rpm kernel-xen-2.6.18-238.40.1.el5.i686.rpm kernel-xen-debuginfo-2.6.18-238.40.1.el5.i686.rpm kernel-xen-devel-2.6.18-238.40.1.el5.i686.rpm ia64: kernel-2.6.18-238.40.1.el5.ia64.rpm kernel-debug-2.6.18-238.40.1.el5.ia64.rpm kernel-debug-debuginfo-2.6.18-238.40.1.el5.ia64.rpm kernel-debug-devel-2.6.18-238.40.1.el5.ia64.rpm kernel-debuginfo-2.6.18-238.40.1.el5.ia64.rpm kernel-debuginfo-common-2.6.18-238.40.1.el5.ia64.rpm kernel-devel-2.6.18-238.40.1.el5.ia64.rpm kernel-headers-2.6.18-238.40.1.el5.ia64.rpm kernel-xen-2.6.18-238.40.1.el5.ia64.rpm kernel-xen-debuginfo-2.6.18-238.40.1.el5.ia64.rpm kernel-xen-devel-2.6.18-238.40.1.el5.ia64.rpm noarch: kernel-doc-2.6.18-238.40.1.el5.noarch.rpm ppc: kernel-2.6.18-238.40.1.el5.ppc64.rpm kernel-debug-2.6.18-238.40.1.el5.ppc64.rpm kernel-debug-debuginfo-2.6.18-238.40.1.el5.ppc64.rpm kernel-debug-devel-2.6.18-238.40.1.el5.ppc64.rpm kernel-debuginfo-2.6.18-238.40.1.el5.ppc64.rpm kernel-debuginfo-common-2.6.18-238.40.1.el5.ppc64.rpm kernel-devel-2.6.18-238.40.1.el5.ppc64.rpm kernel-headers-2.6.18-238.40.1.el5.ppc.rpm kernel-headers-2.6.18-238.40.1.el5.ppc64.rpm kernel-kdump-2.6.18-238.40.1.el5.ppc64.rpm kernel-kdump-debuginfo-2.6.18-238.40.1.el5.ppc64.rpm kernel-kdump-devel-2.6.18-238.40.1.el5.ppc64.rpm s390x: kernel-2.6.18-238.40.1.el5.s390x.rpm kernel-debug-2.6.18-238.40.1.el5.s390x.rpm kernel-debug-debuginfo-2.6.18-238.40.1.el5.s390x.rpm kernel-debug-devel-2.6.18-238.40.1.el5.s390x.rpm kernel-debuginfo-2.6.18-238.40.1.el5.s390x.rpm kernel-debuginfo-common-2.6.18-238.40.1.el5.s390x.rpm kernel-devel-2.6.18-238.40.1.el5.s390x.rpm kernel-headers-2.6.18-238.40.1.el5.s390x.rpm kernel-kdump-2.6.18-238.40.1.el5.s390x.rpm kernel-kdump-debuginfo-2.6.18-238.40.1.el5.s390x.rpm kernel-kdump-devel-2.6.18-238.40.1.el5.s390x.rpm x86_64: kernel-2.6.18-238.40.1.el5.x86_64.rpm kernel-debug-2.6.18-238.40.1.el5.x86_64.rpm kernel-debug-debuginfo-2.6.18-238.40.1.el5.x86_64.rpm kernel-debug-devel-2.6.18-238.40.1.el5.x86_64.rpm kernel-debuginfo-2.6.18-238.40.1.el5.x86_64.rpm kernel-debuginfo-common-2.6.18-238.40.1.el5.x86_64.rpm kernel-devel-2.6.18-238.40.1.el5.x86_64.rpm kernel-headers-2.6.18-238.40.1.el5.x86_64.rpm kernel-xen-2.6.18-238.40.1.el5.x86_64.rpm kernel-xen-debuginfo-2.6.18-238.40.1.el5.x86_64.rpm kernel-xen-devel-2.6.18-238.40.1.el5.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/#package 7. References: https://www.redhat.com/security/data/cve/CVE-2012-2136.html https://access.redhat.com/security/updates/classification/#important 8. Contact: The Red Hat security contact is <email@example.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2012 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (GNU/Linux) iD8DBQFQBb0QXlSAg2UNWIIRAq4XAJ9y1hbIeSgsIZ9Eb1CmobsTaFfG0wCguO40 0Al/6v77xyPQOCKAmeWkFaw= =97g3 -----END PGP SIGNATURE-----