From: Michael S. Tsirkin <mst@redhat.com>
Date: Sun, 17 Mar 2013 02:46:09 +0000 (+0000)
Subject: vhost/net: fix heads usage of ubuf_info
X-Git-Tag: v3.2.42~67
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=984cbc9c6686f399cb4ec5bd8fae5ff8ec2fa9a8;p=pandora-kernel.git

vhost/net: fix heads usage of ubuf_info

commit 46aa92d1ba162b4b3d6b7102440e459d4e4ee255 upstream.

ubuf info allocator uses guest controlled head as an index,
so a malicious guest could put the same head entry in the ring twice,
and we will get two callbacks on the same value.
To fix use upend_idx which is guaranteed to be unique.

Reported-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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