[Secure-testing-team] Bug#809313: CVE-2015-8701: net: rocker: incorrect array bounds check

[Michael Tokarev]

Source: qemu
Version: 1:2.4+dfsg-1
Severity: important
Tags: security patch upstream

CVE-2015-8701 has been reported against qemu.
http://www.openwall.com/lists/oss-security/2015/12/28/6 :

 Qemu emulator built with the Rocker switch emulation support is vulnerable
 to an off-by-one error. It happens while processing transmit(tx) descriptors
 in 'tx_consume' routine, if a descriptor was to have more than allowed 
 (ROCKER_TX_FRAGS_MAX=16) fragments.

 A privileged user inside guest could use this flaw to cause memory leakage
 on the host or crash the Qemu process instance resulting in DoS issue.

 Upstream patch:
 - ---------------
   -> https://lists.gnu.org/archive/html/qemu-devel/2015-12/msg04629.html

 Reference:
 - ----------
   -> https://bugzilla.redhat.com/show_bug.cgi?id=1286971

 This issue was discovered by Mr Qinghao Tang of Qihoo 360 Inc.

rocker is an ethernet switch device introduced after qemu 2.3.