From 46aa92d1ba162b4b3d6b7102440e459d4e4ee255 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 17 Mar 2013 02:46:09 +0000 Subject: [PATCH] vhost/net: fix heads usage of ubuf_info 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 Signed-off-by: Michael S. Tsirkin Cc: stable@kernel.org Signed-off-by: David S. Miller --- drivers/vhost/net.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 959b1cd89e6a..ec6fb3fa59bb 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -339,7 +339,8 @@ static void handle_tx(struct vhost_net *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 = VHOST_DMA_IN_PROGRESS;