3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" <mst@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- 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; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html