Otkriveni su višestruki sigurnosni propusti u radu jezgre operacijskog sustava Red Hat Enterprise Linux 6. Lokalni ih napadači mogu iskoristiti za izvođenje napada uskraćivanjem usluge i dobivanje većih ovlasti.

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                   Red Hat Security Advisory

Synopsis:          Moderate: kernel security and bug fix update
Advisory ID:       RHSA-2012:0350-01
Product:           Red Hat Enterprise Linux
Advisory URL:      https://rhn.redhat.com/errata/RHSA-2012-0350.html
Issue date:        2012-03-06
CVE Names:         CVE-2011-4077 CVE-2011-4081 CVE-2011-4132 
                   CVE-2011-4347 CVE-2011-4594 CVE-2011-4611 
                   CVE-2011-4622 CVE-2012-0038 CVE-2012-0045 
                   CVE-2012-0207 
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1. Summary:

Updated kernel packages that fix various security issues and several bugs
are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
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 Desktop (v. 6) - i386, noarch, x86_64
Red Hat Enterprise Linux Desktop Optional (v. 6) - i386, x86_64
Red Hat Enterprise Linux HPC Node (v. 6) - noarch, x86_64
Red Hat Enterprise Linux HPC Node Optional (v. 6) - x86_64
Red Hat Enterprise Linux Server (v. 6) - i386, noarch, ppc64, s390x, x86_64
Red Hat Enterprise Linux Server Optional (v. 6) - i386, ppc64, s390x, x86_64
Red Hat Enterprise Linux Workstation (v. 6) - i386, noarch, x86_64
Red Hat Enterprise Linux Workstation Optional (v. 6) - i386, 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, Moderate)

* Flaws in ghash_update() and ghash_final() could allow a local,
unprivileged user to cause a denial of service. (CVE-2011-4081, Moderate)

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

* It was found that the kvm_vm_ioctl_assign_device() function in the KVM
(Kernel-based Virtual Machine) subsystem of a Linux kernel did not check if
the user requesting device assignment was privileged or not. A local,
unprivileged user on the host could assign unused PCI devices, or even
devices that were in use and whose resources were not properly claimed by
the respective drivers, which could result in the host crashing.
(CVE-2011-4347, Moderate)

* Two flaws were found in the way the Linux kernel's __sys_sendmsg()
function, when invoked via the sendmmsg() system call, accessed user-space
memory. A local, unprivileged user could use these flaws to cause a denial
of service. (CVE-2011-4594, Moderate)

* The RHSA-2011:1530 kernel update introduced an integer overflow flaw in
the Linux kernel. On PowerPC systems, a local, unprivileged user could use
this flaw to cause a denial of service. (CVE-2011-4611, Moderate)

* A flaw was found in the way the KVM subsystem of a Linux kernel handled
PIT (Programmable Interval Timer) IRQs (interrupt requests) when there was
no virtual interrupt controller set up. A local, unprivileged user on the
host could force this situation to occur, resulting in the host crashing.
(CVE-2011-4622, Moderate)

* A flaw was found in the way the Linux kernel's XFS file system
implementation handled on-disk Access Control Lists (ACLs). 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-2012-0038, Moderate)

* A flaw was found in the way the Linux kernel's KVM hypervisor
implementation emulated the syscall instruction for 32-bit guests. An
unprivileged guest user could trigger this flaw to crash the guest.
(CVE-2012-0045, Moderate)

* A divide-by-zero flaw was found in the Linux kernel's igmp_heard_query()
function. An attacker able to send certain IGMP (Internet Group Management
Protocol) packets to a target system could use this flaw to cause a denial
of service. (CVE-2012-0207, Moderate)

Red Hat would like to thank Nick Bowler for reporting CVE-2011-4081; Sasha
Levin for reporting CVE-2011-4347; Tetsuo Handa for reporting
CVE-2011-4594; Maynard Johnson for reporting CVE-2011-4611; Wang Xi for
reporting CVE-2012-0038; Stephan BÄ