tcp: len check is unnecessarily devastating, change to WARN_ON

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 <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index dfa5beb0c1c8..8b0d0167e44a 100644
--- 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)