| Date | Mon, 25 Mar 2013 01:05:49 +0000 | From | Ben Hutchings <> | Subject | [ 025/104] vhost/net: fix heads usage of ubuf_info |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: "Michael S. Tsirkin" <mst@redhat.com>
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> --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -234,7 +234,8 @@ static void handle_tx(struct vhost_net * msg.msg_controllen = 0; ubufs = NULL; } else { - struct ubuf_info *ubuf = &vq->ubuf_info[head]; + struct ubuf_info *ubuf; + ubuf = vq->ubuf_info + vq->upend_idx; vq->heads[vq->upend_idx].len = len; ubuf->callback = vhost_zerocopy_callback;
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