7.2 - RHSA-2011:0883

Problem Description:

Updated kernel packages that fix several 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 in the References section.

2. Relevant releases/architectures:

Red Hat Enterprise Linux Server (v. 6.0.z) - i386, noarch, ppc64, s390x, x86_64

3. Description:

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.

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

4. Solution:

Users should upgrade to these updated packages, which contain backported patches to resolve these issues, and fix the bugs noted in the Technical Notes. The system must be rebooted for this update to take effect.

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/):

649920 - CVE-2010-3881 kvm: arch/x86/kvm/x86.c: reading uninitialized stack memory 657303 - CVE-2010-4251 CVE-2010-4805 kernel: unlimited socket backlog DoS 678209 - CVE-2011-0999 kernel: thp: prevent hugepages during args/env copying into the user stack 679282 - CVE-2011-1010 kernel: fs/partitions: Validate map_count in Mac partition tables 681575 - CVE-2011-1082 kernel: potential kernel deadlock when creating circular epoll file structures 682641 - CVE-2011-1090 kernel: nfs4: Ensure that ACL pages sent over NFS were not allocated from the slab 688021 - CVE-2011-1163 kernel: fs/partitions: Corrupted OSF partition table infoleak 689321 - CVE-2011-1170 kernel: ipv4: netfilter: arp_tables: fix infoleak to userspace 689327 - CVE-2011-1171 kernel: ipv4: netfilter: ip_tables: fix infoleak to userspace 689345 - CVE-2011-1172 kernel: ipv6: netfilter: ip6_tables: fix infoleak to userspace 690028 - CVE-2011-1182 kernel signal spoofing issue 694021 - CVE-2011-1494 CVE-2011-1495 kernel: drivers/scsi/mpt2sas: prevent heap overflows