Date: 11 July 2014
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AUSCERT External Security Bulletin Redistribution
Xen Security Advisory XSA-101
11 July 2014
AusCERT Security Bulletin Summary
Operating System: UNIX variants (UNIX, Linux, OSX)
Impact/Access: Access Confidential Data -- Existing Account
CVE Names: CVE-2014-4022
Revision History: July 11 2014: Provide the CVE.
June 27 2014: Initial Release
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Xen Security Advisory CVE-2014-4022 / XSA-101
information leak via gnttab_setup_table on ARM
UPDATES IN VERSION 3
Provide the CVE.
When initialising an internal data structure on ARM platform Xen was
not correctly initialising the memory containing the list of a
domain's grant table pages. This list is returned by the
GNTTABOP_setup_table subhypercall, leading to an information leak.
Malicious guest administrators can obtain some of the memory contents
of other domains:
Up to 8*max_nr_grant_frames bytes of uninitialised memory can be
leaked to the calling domain. This memory may have been previously
used by either the hypervisor or other guests.
The default max_nr_grant_frames is 32, hence by default 256 bytes may
be leaked in this way. However this can be overridden via the
"gnttab_max_nr_frames" hypervisor command line option.
Both 32- and 64-bit ARM systems are vulnerable from Xen 4.4 onward.
This issue was discovered by Julien Grall.
Applying the attached patch resolves this issue.
xsa101.patch xen-unstable, Xen 4.4.x
$ sha256sum xsa101*.patch
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