RDAM/netlink: Fix out-of-bound access while checking message validity

The netlink message sent with type == 0, which doesn't have any client
behind it, caused to the overflow in max_num_ops array.

Fix it by declaring zero number of ops for the first client.

Fixes: c990172 ("RDMA/netlink: Remove netlink clients infrastructure")
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Author: rleon

drivers/infiniband/core/netlink.c

@@ -57,7 +57,8 @@ EXPORT_SYMBOL(rdma_nl_chk_listeners);
 
 static bool is_nl_msg_valid(unsigned int type, unsigned int op)
 {
-	static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS - 1] = {
+	static const unsigned int max_num_ops[RDMA_NL_NUM_CLIENTS] = {
+				  0,
 				  RDMA_NL_RDMA_CM_NUM_OPS,
 				  RDMA_NL_IWPM_NUM_OPS,
 				  0,
@@ -70,10 +71,10 @@ static bool is_nl_msg_valid(unsigned int type, unsigned int op)
 	 */
 	BUILD_BUG_ON(RDMA_NL_NUM_CLIENTS != 6);
 
-	if (type > RDMA_NL_NUM_CLIENTS - 1)
+	if (type >= RDMA_NL_NUM_CLIENTS)
 		return false;
 
-	return (op < max_num_ops[type - 1]) ? true : false;
+	return (op < max_num_ops[type]) ? true : false;
 }
 
 static bool is_nl_valid(unsigned int type, unsigned int op)