Scientific Linux Security Update : xen on SL5.x i386/x86_64

This script is Copyright (C) 2012-2014 Tenable Network Security, Inc.


Synopsis :

The remote Scientific Linux host is missing one or more security
updates.

Description :

The xen packages contain administration tools and the xend service for
managing the kernel-xen kernel for virtualization on Scientific Linux.

A buffer overflow flaw was found in the Xen hypervisor SCSI subsystem
emulation. An unprivileged, local guest user could provide a large
number of bytes that are used to zero out a fixed-sized buffer via a
SAI READ CAPACITY SCSI command, overwriting memory and causing the
guest to crash. (CVE-2011-3346)

This update also fixes the following bugs :

- Prior to this update, the vif-bridge script used a
maximum transmission unit (MTU) of 1500 for a new
Virtual Interface (VIF). As a result, the MTU of the VIF
could differ from that of the target bridge. This update
fixes the VIF hot-plug script so that the default MTU
for new VIFs will match that of the target Xen
hypervisor bridge. In combination with a new enough
kernel, this enables the use of jumbo frames in Xen
hypervisor guests.

- Prior to this update, the network-bridge script set the
MTU of the bridge to 1500. As a result, the MTU of the
Xen hypervisor bridge could differ from that of the
physical interface. This update fixes the network script
so the MTU of the bridge can be set higher than 1500,
thus also providing support for jumbo frames. Now, the
MTU of the Xen hypervisor bridge will match that of the
physical interface.

- Scientific Linux 5.6 introduced an optimized migration
handling that speeds up the migration of guests with
large memory. However, the new migration procedure can
theoretically cause data corruption. While no cases were
observed in practice, with this update, the xend daemon
properly waits for correct device release before the
guest is started on a destination machine, thus fixing
this bug.

Note: Before a guest is using a new enough kernel, the MTU of the VIF
will drop back to 1500 (if it was set higher) after migration.

All xen users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing
the updated packages, the xend service must be restarted for this
update to take effect.

See also :

http://www.nessus.org/u?310d69db

Solution :

Update the affected packages.

Risk factor :

Medium / CVSS Base Score : 4.0
(CVSS2#AV:L/AC:H/Au:N/C:N/I:N/A:C)

Family: Scientific Linux Local Security Checks

Nessus Plugin ID: 61163 ()

Bugtraq ID:

CVE ID: CVE-2011-3346