xsk: fix to reject invalid options in Tx descriptor

Passing a non-existing option in the options member of struct xdp_desc was, incorrectly, silently ignored. This patch addresses that behavior, and drops any Tx descriptor with non-existing options. We have examined existing user space code, and to our best knowledge, no one is relying on the current incorrect behavior. AF_XDP is still in its infancy, so from our perspective, the risk of breakage is very low, and addressing this problem now is important. Fixes: 35fcde7 ("xsk: support for Tx") Signed-off-by: Björn Töpel <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
fracktal · Mar 8, 2019 · c57b557 · c57b557
1 parent f54ba39
commit c57b557
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
@@ -174,8 +174,8 @@ static inline bool xskq_is_valid_desc(struct xsk_queue *q, struct xdp_desc *d)
 	if (!xskq_is_valid_addr(q, d->addr))
 		return false;
 
-	if (((d->addr + d->len) & q->chunk_mask) !=
-	    (d->addr & q->chunk_mask)) {
+	if (((d->addr + d->len) & q->chunk_mask) != (d->addr & q->chunk_mask) ||
+	    d->options) {
 		q->invalid_descs++;
 		return false;
 	}