Xen.org security team
2013-Oct-10 12:22 UTC
Xen Security Advisory 70 (CVE-2013-4371) - use-after-free in libxl_list_cpupool under memory pressure
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Xen Security Advisory CVE-2013-4371 / XSA-70
version 2
use-after-free in libxl_list_cpupool under memory pressure
UPDATES IN VERSION 2
===================
Public release.
ISSUE DESCRIPTION
================
If realloc(3) fails then libxl_list_cpupool will incorrectly return
the now-free original pointer.
IMPACT
=====
An attacker may be able to cause a multithreaded toolstack using this
function to race against itself leading to heap corruption and a
potential DoS.
Depending on the malloc implementation code execution cannot be ruled
out.
VULNERABLE SYSTEMS
=================
The flaw is present in Xen 4.2 onwards.
Systems using the libxl toolstack library are vulnerable.
MITIGATION
=========
Not calling the libxl_list_cpupool function will avoid this issue.
Not allowing untrusted users access to toolstack functionality will
avoid this issue.
CREDITS
======
This issue was discovered by Coverity Scan and Matthew Daley.
RESOLUTION
=========
Applying the attached patch resolves this issue.
xsa70.patch Xen 4.3.x, Xen 4.2.x, xen-unstable
$ sha256sum xsa70*.patch
2582d3d545903af475436145f7e459414ad9d9c61d5720992eeeec42de8dde56 xsa70.patch
$
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