[PATCH v3 2/2] vhost: improve error handling in desc_to_mbuf

[Claudio Fontana <cfontana@suse.de>]

check when increasing vec_idx that it is still valid
in the (buf_len < dev->vhost_hlen) case too.

Tested-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Claudio Fontana <cfontana@suse.de>
---
 lib/vhost/virtio_net.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index eb19e54c2b..20ed951979 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -2704,12 +2704,15 @@ desc_to_mbuf(struct virtio_net *dev, struct vhost_virtqueue *vq,
 	if (unlikely(buf_len < dev->vhost_hlen)) {
 		buf_offset = dev->vhost_hlen - buf_len;
 		vec_idx++;
+		if (unlikely(vec_idx >= nr_vec))
+			goto error;
 		buf_addr = buf_vec[vec_idx].buf_addr;
 		buf_iova = buf_vec[vec_idx].buf_iova;
 		buf_len = buf_vec[vec_idx].buf_len;
 		buf_avail  = buf_len - buf_offset;
 	} else if (buf_len == dev->vhost_hlen) {
-		if (unlikely(++vec_idx >= nr_vec))
+		vec_idx++;
+		if (unlikely(vec_idx >= nr_vec))
 			goto error;
 		buf_addr = buf_vec[vec_idx].buf_addr;
 		buf_iova = buf_vec[vec_idx].buf_iova;
-- 
2.26.2