RHEL 6 : kernel (RHSA-2015:1583)

This script is Copyright (C) 2015-2017 Tenable Network Security, Inc.


Synopsis :

The remote Red Hat host is missing one or more security updates.

Description :

Updated kernel packages that fix one security issue and several bugs
are now available for Red Hat Enterprise Linux 6.5 Extended Update
Support.

Red Hat Product Security has rated this update as having Moderate
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.

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

* It was found that the Linux kernel's ping socket implementation did
not properly handle socket unhashing during spurious disconnects,
which could lead to a use-after-free flaw. On x86-64 architecture
systems, a local user able to create ping sockets could use this flaw
to crash the system. On non-x86-64 architecture systems, a local user
able to create ping sockets could use this flaw to escalate their
privileges on the system. (CVE-2015-3636, Moderate)

This update also fixes the following bugs :

* Previously, the bridge device did not propagate VLAN information to
its ports and Generic Receive Offload (GRO) information to devices
that sit on top. This resulted in lower receive performance of VLANs
over bridge devices because GRO was not enabled. An attempt to resolve
this problem was made with BZ#858198 by introducing a patch that
allows VLANs to be registered with the participating bridge ports and
adds GRO to the bridge device feature set, however, that attempt
introduced a number of regressions, which broke the vast majority of
stacked setups involving bridge devices and VLANs. This update reverts
the patch provided by BZ#858198 and removes support for this
capability. (BZ#1131697)

* The backlog data could previously not be consumed when the
audit_log_start() function was running even if audit_log_start()
called the wait_for_auditd() function to consume it. As only auditd
could consume the backlog data, audit_log_start() terminated
unexpectedly. Consequently, the system became unresponsive until the
backlog timeout was up again. With this update, audit_log_start() no
longer terminates and the system shuts down and reboots gracefully in
a timely manner. (BZ#1140490)

* This update introduces a set of patches with a new VLAN model to
conform to upstream standards. In addition, this set of patches fixes
other issues such as transmission of Internet Control Message Protocol
(ICMP) fragments. (BZ#1173560)

* Due to a bug in the audit code, a kernel panic occurred in the
tasklist_lock variable if SELinux was in permissive or enforcing mode.
A patch has been applied to fix this bug, and the operating system now
continues to work normally. (BZ#1236103)

* If a server returned an empty or malformed READDIR response, the NFS
client could previously terminate unexpectedly while attempting to
decode that response. This update uses the response size to determine
if existing pages of data are available for decoding, and the client
only decodes the responses if they exist. As a result, the NFS client
no longer attempts to decode pages of data that may not exist, and the
aforementioned crash is thus avoided. (BZ#1232133)

* Previously, if a slave device had a receive handler registered, then
an error unwind of bonding device enslave function became broken,
which led to a kernel oops. This update detaches the slave in the
unwind path, and the aforementioned oops no longer occurs.
(BZ#1222482)

* Due to bad memory or memory corruption, an isolated
BUG_ON(mm->nr_ptes) was sometimes reported, indicating that not all
the page tables allocated could be found and freed when the
exit_mmap() function cleared the user address space. As a consequence,
a kernel panic occurred. To fix this bug, the BUG_ON() function has
been replaced by WARN_ON(), which prevents the kernel from panicking
in the aforementioned situation. (BZ#1235930)

All kernel users are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. The system
must be rebooted for this update to take effect.

See also :

https://www.redhat.com/security/data/cve/CVE-2015-3636.html
http://rhn.redhat.com/errata/RHSA-2015-1583.html

Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 4.9
(CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:C)
CVSS Temporal Score : 4.3
(CVSS2#E:H/RL:OF/RC:ND)
Public Exploit Available : true

Family: Red Hat Local Security Checks

Nessus Plugin ID: 85341 ()

Bugtraq ID:

CVE ID: CVE-2015-3636

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