Xen.org security team
2013-Oct-10 12:22 UTC
Xen Security Advisory 68 (CVE-2013-4369) - possible null dereference when parsing vif ratelimiting info
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Xen Security Advisory CVE-2013-4369 / XSA-68
version 2
possible null dereference when parsing vif ratelimiting info
UPDATES IN VERSION 2
===================
Public release.
ISSUE DESCRIPTION
================
The libxlu library function xlu_vif_parse_rate does not properly
handle inputs which consist solely of the ''@'' character,
leading to a
NULL pointer dereference.
IMPACT
=====
A toolstack which allows untrusted users to specify an arbitrary
configuration for the VIF rate can be subjected to a DOS.
The only known user of this library is the xl toolstack which does not
have a central long running daemon and therefore the impact is limited
to crashing the process which is creating the domain, which exists
only to service a single domain.
VULNERABLE SYSTEMS
=================
The vulnerable code is present from Xen 4.2 onwards.
MITIGATION
=========
Disallowing untrusted users from specifying arbitrary VIF rate limits
will avoid this issue.
CREDITS
======
This issue was discovered by Coverity Scan and Matthew Daley.
RESOLUTION
=========
Applying the attached patch resolves this issue in all branches
xsa68.patch xen-unstable, Xen 4.3.x, Xen 4.2.x
$ sha256sum xsa68*.patch
64716cb49696298e0bbd9556fe9d6f559a4e2785081e28d50607317b6e27ba32 xsa68.patch
$
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