Messages in this thread Patch in this message | | | Date | Tue, 14 Sep 2010 15:15:52 +0200 | From | "Michael S. Tsirkin" <> | Subject | [PATCH] vhost-net: fix range checking in mrg bufs case |
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In mergeable buffer case, we use headcount, log_num and seg as indexes in same-size arrays, and we know that headcount <= seg and log_num equals either 0 or seg.
Therefore, the right thing to do is range-check seg, not headcount as we do now: these will be different if guest chains s/g descriptors (this does not happen now, but we can not trust the guest).
Long term, we should add BUG_ON checks to verify two other indexes are what we think they should be.
Reported-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> ---
Dave, I'll queue this on my tree, no need to bother.
drivers/vhost/net.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 6400cd5..f095de6 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -245,7 +245,7 @@ static int get_rx_bufs(struct vhost_virtqueue *vq, int r, nlogs = 0; while (datalen > 0) { - if (unlikely(headcount >= VHOST_NET_MAX_SG)) { + if (unlikely(seg >= VHOST_NET_MAX_SG)) { r = -ENOBUFS; goto err; } -- 1.7.3.rc1.5.ge5969
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