B.38.9. RHSA-2011:0883 — Important: kernel security and bug fix update

Important

This update has already been released as the security errata RHSA-2011:0883
Updated kernel packages that fix multiple security issues and three bugs are now available for Red Hat Enterprise Linux 6.0 Extended Update Support.
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 after each description below.
The kernel packages contain the Linux kernel, the core of any Linux operating system.
This update includes backported fixes for security issues. These issues, except for CVE-2011-1182, only affected users of Red Hat Enterprise Linux 6.0 Extended Update Support as they have already been addressed for users of Red Hat Enterprise Linux 6 in the 6.1 update, RHSA-2011:0542.
Security fixes
* Buffer overflow flaws were found in the Linux kernel's Management Module Support for Message Passing Technology (MPT) based controllers. A local, unprivileged user could use these flaws to cause a denial of service, an information leak, or escalate their privileges. (CVE-2011-1494, CVE-2011-1495, Important)
* A flaw was found in the Linux kernel's networking subsystem. If the number of packets received exceeded the receiver's buffer limit, they were queued in a backlog, consuming memory, instead of being discarded. A remote attacker could abuse this flaw to cause a denial of service (out-of-memory condition). (CVE-2010-4251, CVE-2010-4805, Moderate)
* A flaw was found in the Linux kernel's Transparent Huge Pages (THP) implementation. A local, unprivileged user could abuse this flaw to allow the user stack (when it is using huge pages) to grow and cause a denial of service. (CVE-2011-0999, Moderate)
* A flaw in the Linux kernel's Event Poll (epoll) implementation could allow a local, unprivileged user to cause a denial of service. (CVE-2011-1082, Moderate)
* An inconsistency was found in the interaction between the Linux kernel's method for allocating NFSv4 (Network File System version 4) ACL data and the method by which it was freed. This inconsistency led to a kernel panic which could be triggered by a local, unprivileged user with files owned by said user on an NFSv4 share. (CVE-2011-1090, Moderate)
* It was found that some structure padding and reserved fields in certain data structures in KVM (Kernel-based Virtual Machine) were not initialized properly before being copied to user-space. A privileged host user with access to /dev/kvm could use this flaw to leak kernel stack memory to user-space. (CVE-2010-3881, Low)
* A missing validation check was found in the Linux kernel's mac_partition() implementation, used for supporting file systems created on Mac OS operating systems. A local attacker could use this flaw to cause a denial of service by mounting a disk that contains specially-crafted partitions. (CVE-2011-1010, Low)
* A buffer overflow flaw in the DEC Alpha OSF partition implementation in the Linux kernel could allow a local attacker to cause an information leak by mounting a disk that contains specially-crafted partition tables. (CVE-2011-1163, Low)
* Missing validations of null-terminated string data structure elements in the do_replace(), compat_do_replace(), do_ipt_get_ctl(), do_ip6t_get_ctl(), and do_arpt_get_ctl() functions could allow a local user who has the CAP_NET_ADMIN capability to cause an information leak. (CVE-2011-1170, CVE-2011-1171, CVE-2011-1172, Low)
* A missing validation check was found in the Linux kernel's signals implementation. A local, unprivileged user could use this flaw to send signals via the sigqueueinfo system call, with the si_code set to SI_TKILL and with spoofed process and user IDs, to other processes. Note: This flaw does not allow existing permission checks to be bypassed; signals can only be sent if your privileges allow you to already do so. (CVE-2011-1182, Low)
Red Hat would like to thank Dan Rosenberg for reporting CVE-2011-1494 and CVE-2011-1495; Nelson Elhage for reporting CVE-2011-1082; Vasiliy Kulikov for reporting CVE-2010-3881, CVE-2011-1170, CVE-2011-1171, and CVE-2011-1172; Timo Warns for reporting CVE-2011-1010 and CVE-2011-1163; and Julien Tinnes of the Google Security Team for reporting CVE-2011-1182.
Bug fixes
BZ#590187
Previously, CPUs kept continuously locking up in the inet_csk_bind_conflict() function until the entire system became unreachable when all the CPUs were unresponsive due to a hash locking issue when using port redirection in the __inet_inherit_port() function. With this update, the underlying source code of the __inet_inherit_port() function has been modified to address this issue, and CPUs no longer lock up.
BZ#709380
A previously released patch for BZ#625487 introduced a kABI (Kernel Application Binary Interface) workaround that extended struct sock (the network layer representation of sockets) by putting the extension structure in the memory right after the original structure. As a result, the prot->obj_size pointer had to be adjusted in the proto_register function. Prior to this update, the adjustment was done only if the alloc_slab parameter of the proto_register function was not 0. When the alloc_slab parameter was 0, drivers performed allocations themselves using sk_alloc and as the allocated memory was lower than needed, a memory corruption could occur. With this update, the underlying source code has been modified to address this issue, and a memory corruption no longer occurs.
BZ#706543
An IDX ACTIVATE timeout occurred during an online setting of an OSN device. This was because an incorrect function was provided on the IDX ACTIVATE. Because OSN devices use the same function level as OSD devices, this update adds OSN devices to the initialization function for the func_level; thus, resolving this issue.
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.