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From: Paolo Abeni <pabeni at redhat.com>
To: mptcp at lists.01.org
Subject: [MPTCP] [PATCH net] inet_connection_sock: clear inet_num out of destroy helper
Date: Thu, 04 Jun 2020 18:55:45 +0200	[thread overview]
Message-ID: <cc2adbd7dcc17c44e2858e550302906760b38a0b.1591289527.git.pabeni@redhat.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 1827 bytes --]

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 <cpaasch(a)apple.com>
Fixes: 729cd6436f35 ("mptcp: cope better with MP_JOIN failure")
Signed-off-by: Paolo Abeni <pabeni(a)redhat.com>
---
 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 2f1f8c3efb26..e5b388f5fa20 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 f40b1b72f979..afaf582a5aa9 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);
 
-- 
2.21.3

WARNING: multiple messages have this Message-ID (diff)
From: Paolo Abeni <pabeni@redhat.com>
To: netdev@vger.kernel.org
Cc: Mat Martineau <mathew.j.martineau@linux.intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	mptcp@lists.01.org, Eric Dumazet <edumazet@google.com>,
	Christoph Paasch <cpaasch@apple.com>
Subject: [PATCH net] inet_connection_sock: clear inet_num out of destroy helper
Date: Thu,  4 Jun 2020 18:55:45 +0200	[thread overview]
Message-ID: <cc2adbd7dcc17c44e2858e550302906760b38a0b.1591289527.git.pabeni@redhat.com> (raw)

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 <cpaasch@apple.com>
Fixes: 729cd6436f35 ("mptcp: cope better with MP_JOIN failure")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 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 2f1f8c3efb26..e5b388f5fa20 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 f40b1b72f979..afaf582a5aa9 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);
 
-- 
2.21.3


             reply	other threads:[~2020-06-04 16:55 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-04 16:55 Paolo Abeni [this message]
2020-06-04 16:55 ` [PATCH net] inet_connection_sock: clear inet_num out of destroy helper Paolo Abeni
2020-06-04 17:43 [MPTCP] " Eric Dumazet
2020-06-04 17:43 ` Eric Dumazet
2020-06-04 23:00 [MPTCP] " David Miller
2020-06-04 23:00 ` David Miller

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