Commit c2f34a65 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fb0801dc
...@@ -137,6 +137,10 @@ int __inet_inherit_port(const struct sock *sk, struct sock *child) ...@@ -137,6 +137,10 @@ int __inet_inherit_port(const struct sock *sk, struct sock *child)
spin_lock(&head->lock); spin_lock(&head->lock);
tb = inet_csk(sk)->icsk_bind_hash; tb = inet_csk(sk)->icsk_bind_hash;
if (unlikely(!tb)) {
spin_unlock(&head->lock);
return -ENOENT;
}
if (tb->port != port) { if (tb->port != port) {
/* NOTE: using tproxy and redirecting skbs to a proxy /* NOTE: using tproxy and redirecting skbs to a proxy
* on a different listener port breaks the assumption * on a different listener port breaks the assumption
......
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