From 5b67054b7a7adc149b8b4371ada3c520e595457a Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 5 Jun 2020 18:10:21 +0000 Subject: [PATCH] inet_connection_sock: clear inet_num out of destroy helper Clearing the 'inet_num' field is necessary and safe if and only if the socket is not bound. The MPTCP protocol calls the destroy helper on bound sockets, as tcp_v{4,6}_syn_recv_sock completed successfully. Move the clearing of such field out of the common code, otherwise the MPTCP MP_JOIN error path will find the wrong 'inet_num' value on socket disposal, __inet_put_port() will acquire the wrong lock and bind_node removal could race with other modifiers possibly corrupting the bind hash table. Reported-and-tested-by: Christoph Paasch Fixes: 729cd6436f35 ("mptcp: cope better with MP_JOIN failure") Signed-off-by: Paolo Abeni --- include/net/inet_connection_sock.h | 1 - net/ipv4/inet_connection_sock.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 2f1f8c3efb260..e5b388f5fa209 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -292,7 +292,6 @@ static inline void inet_csk_prepare_for_destroy_sock(struct sock *sk) /* The below has to be done to allow calling inet_csk_destroy_sock */ sock_set_flag(sk, SOCK_DEAD); percpu_counter_inc(sk->sk_prot->orphan_count); - inet_sk(sk)->inet_num = 0; } void inet_csk_destroy_sock(struct sock *sk); diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index f40b1b72f9791..afaf582a5aa99 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -902,6 +902,7 @@ void inet_csk_prepare_forced_close(struct sock *sk) bh_unlock_sock(sk); sock_put(sk); inet_csk_prepare_for_destroy_sock(sk); + inet_sk(sk)->inet_num = 0; } EXPORT_SYMBOL(inet_csk_prepare_forced_close);