Commit 46aa92d1 authored Mar 17, 2013 by Michael S. Tsirkin Committed by David S. Miller Mar 17, 2013

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 <rusty@rustcorp.com.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3d84fa98

drivers/vhost/net.c

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -339,7 +339,8 @@ static void handle_tx(struct vhost_net *net)
	msg.msg_controllen = 0;		msg.msg_controllen = 0;
	ubufs = NULL;		ubufs = NULL;
	} else {		} 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 =		vq->heads[vq->upend_idx].len =
	VHOST_DMA_IN_PROGRESS;		VHOST_DMA_IN_PROGRESS;

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