32 lines
1.1 KiB
Diff
32 lines
1.1 KiB
Diff
From: "Michael S. Tsirkin" <mst@redhat.com>
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Date: Sun, 17 Mar 2013 02:46:09 +0000
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Subject: vhost/net: fix heads usage of ubuf_info
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commit 46aa92d1ba162b4b3d6b7102440e459d4e4ee255 upstream.
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ubuf info allocator uses guest controlled head as an index,
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so a malicious guest could put the same head entry in the ring twice,
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and we will get two callbacks on the same value.
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To fix use upend_idx which is guaranteed to be unique.
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Reported-by: Rusty Russell <rusty@rustcorp.com.au>
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Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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---
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drivers/vhost/net.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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--- a/drivers/vhost/net.c
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+++ b/drivers/vhost/net.c
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@@ -339,7 +339,8 @@ static void handle_tx(struct vhost_net *
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msg.msg_controllen = 0;
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ubufs = NULL;
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} else {
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- struct ubuf_info *ubuf = &vq->ubuf_info[head];
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+ struct ubuf_info *ubuf;
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+ ubuf = vq->ubuf_info + vq->upend_idx;
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vq->heads[vq->upend_idx].len =
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VHOST_DMA_IN_PROGRESS;
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