tcp: len check is unnecessarily devastating, change to WARN_ON

ij1 · davem330 · commit 2fceec13375e · 2011-04-01T21:47:41.000-07:00
All callers are prepared for alloc failures anyway, so this error
can safely be boomeranged to the callers domain without super
bad consequences. ...At worst the connection might go into a state
where each RTO tries to (unsuccessfully) re-fragment with such
a mis-sized value and eventually dies.

Signed-off-by: Ilpo Järvinen &lt;ilpo.jarvinen@helsinki.fi&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
@@ -1003,7 +1003,8 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
 	int nlen;
 	u8 flags;
 
-	BUG_ON(len > skb->len);
+	if (WARN_ON(len > skb->len))
+		return -EINVAL;
 
 	nsize = skb_headlen(skb) - len;
 	if (nsize < 0)
