Commit 46aa92d1 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by David S. Miller

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: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Cc: stable@kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3d84fa98
...@@ -339,7 +339,8 @@ static void handle_tx(struct vhost_net *net) ...@@ -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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