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@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
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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