An internal flag is used to temporarily suppress IOMMU TLB flushes, in
order to consolidate multiple single page flushes into one wider
flush. This flag is not cleared again, on certain error paths. This
can result in TLB flushes not happening when they are needed.
Retaining stale TLB entries could allow guests access to memory that
ought to have been revoked, or grant greater access than intended.
Patch available, see
Whoops, hit post too early. Patch is at http://seclists.org/oss-sec/2013/q4/att-459/xsa80.patch. Calling this B4, info leak.
Xen 4.2.x and 4.3.x, when using Intel VT-d and a PCI device has been
assigned, does not clear the flag that suppresses IOMMU TLB flushes when
unspecified errors occur, which causes the TLB entries to not be flushed and
allows local guest administrators to cause a denial of service (host crash)
or gain privileges via unspecified vectors.
Per the Secunia advisory (http://secunia.com/advisories/55932), it appears this vulnerability, when successfully exploited, can be used by malicious local users to gain escalated privileges. Thus, escalating this to B1.
*xen-4.3.1-r3 (06 Jan 2014)
*xen-4.3.0-r6 (06 Jan 2014)
06 Jan 2014; Ian Delaney <email@example.com>
add new sec patches, revbumps, patches prepared by dlan
Are we ready to stabilize the versions that are committed?
Fixed as part of Bug 500530.
Adding to existing GLSA.
This issue was resolved and addressed in
GLSA 201407-03 at http://security.gentoo.org/glsa/glsa-201407-03.xml
by GLSA coordinator Mikle Kolyada (Zlogene).