tipc: Add sanity check to detect rejection of non-payload messages

Introduces an internal sanity check to ensure that the only undeliverable
messages TIPC attempts to return to their origin are application payload
messages.

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/tipc/port.c b/net/tipc/port.c
index 3946b5b10c74..756e64cbff96 100644
--- a/net/tipc/port.c
+++ b/net/tipc/port.c
@@ -367,6 +367,12 @@ int tipc_reject_msg(struct sk_buff *buf, u32 err)
                 imp++;
 
         /* discard rejected message if it shouldn't be returned to sender */
+
+        if (WARN(!msg_isdata(msg),
+                 "attempt to reject message with user=%u", msg_user(msg))) {
+                dump_stack();
+                goto exit;
+        }
         if (msg_errcode(msg) || msg_dest_droppable(msg))
                 goto exit;