Commit c2f34a65 authored Oct 14, 2015 by Eric Dumazet Committed by David S. Miller Oct 14, 2015

tcp/dccp: fix potential NULL deref in __inet_inherit_port()



As we no longer hold listener lock in fast path, it is possible that a
child is created right after listener freed its bound port, if a close()
is done while incoming packets are processed.

__inet_inherit_port() must detect this and return an error,
so that caller can free the child earlier.

Fixes: e994b2f0 ("tcp: do not lock listener to process SYN packets")
Fixes: 079096f1 ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent fb0801dc

net/ipv4/inet_hashtables.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -137,6 +137,10 @@ int __inet_inherit_port(const struct sock sk, struct sock child)

		spin_lock(&head->lock);
		tb = inet_csk(sk)->icsk_bind_hash;
		if (unlikely(!tb)) {
		spin_unlock(&head->lock);
		return -ENOENT;
		}
		if (tb->port != port) {
		/* NOTE: using tproxy and redirecting skbs to a proxy
		* on a different listener port breaks the assumption