Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Matthieu Baerts <matthieu.baerts@tessares.net>
Date:   Fri, 11 Aug 2023 17:57:14 +0200
Subject: [PATCH net-next 01/14] mptcp: avoid unneeded mptcp_token_destroy()
 calls
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-Id: <20230811-upstream-net-next-20230811-mptcp-get-rid-of-msk-subflow-v1-1-36183269ade8@tessares.net>
References: <20230811-upstream-net-next-20230811-mptcp-get-rid-of-msk-subflow-v1-0-36183269ade8@tessares.net>
In-Reply-To: <20230811-upstream-net-next-20230811-mptcp-get-rid-of-msk-subflow-v1-0-36183269ade8@tessares.net>
To:     mptcp@lists.linux.dev, Mat Martineau <martineau@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        David Ahern <dsahern@kernel.org>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        Matthieu Baerts <matthieu.baerts@tessares.net>
Precedence: bulk

From: Paolo Abeni <pabeni@redhat.com>

The MPTCP protocol currently clears the msk token both at connect() and
listen() time. That is needed to deal with failing connect() calls that
can create a new token while leaving the sk in TCP_CLOSE,SS_UNCONNECTED
status and thus allowing later connect() and/or listen() calls.

Let's deal with such failures explicitly, cleaning the token in a timely
manner and avoid the confusing early mptcp_token_destroy().

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
 net/mptcp/protocol.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 48e649fe2360..abb310548c37 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -3594,7 +3594,6 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	if (IS_ERR(ssock))
 		return PTR_ERR(ssock);
 
-	mptcp_token_destroy(msk);
 	inet_sk_state_store(sk, TCP_SYN_SENT);
 	subflow = mptcp_subflow_ctx(ssock->sk);
 #ifdef CONFIG_TCP_MD5SIG
@@ -3624,6 +3623,8 @@ static int mptcp_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
 	 * subflow_finish_connect()
 	 */
 	if (unlikely(err && err != -EINPROGRESS)) {
+		/* avoid leaving a dangling token in an unconnected socket */
+		mptcp_token_destroy(msk);
 		inet_sk_state_store(sk, inet_sk_state_load(ssock->sk));
 		return err;
 	}
@@ -3713,7 +3714,6 @@ static int mptcp_listen(struct socket *sock, int backlog)
 		goto unlock;
 	}
 
-	mptcp_token_destroy(msk);
 	inet_sk_state_store(sk, TCP_LISTEN);
 	sock_set_flag(sk, SOCK_RCU_FREE);
 

-- 
2.40.1