netdev - [PATCH net 3/3] mptcp: drop req socket remote

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Date:   Mon, 20 Apr 2020 16:25:06 +0200
From:   Paolo Abeni <pabeni@...hat.com>
To:     netdev@...r.kernel.org
Cc:     Mat Martineau <mathew.j.martineau@...ux.intel.com>,
        Matthieu Baerts <matthieu.baerts@...sares.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Christoph Paasch <cpaasch@...le.com>,
        Florian Westphal <fw@...len.de>
Subject: [PATCH net 3/3] mptcp: drop req socket remote_key* fields

We don't need them, as we can use the current ingress opt
data instead. Setting them in syn_recv_sock() may causes
inconsistent mptcp socket status, as per previous commit.

Fixes: cc7972ea1932 ("mptcp: parse and emit MP_CAPABLE option according to v1 spec")
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
 net/mptcp/protocol.c |  8 +++++---
 net/mptcp/protocol.h |  8 ++++----
 net/mptcp/subflow.c  | 20 ++++++++++----------
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index d275c1e827fe..58ad03fc1bbc 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1345,7 +1345,9 @@ static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
 }
 #endif
 
-struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req)
+struct sock *mptcp_sk_clone(const struct sock *sk,
+			    const struct tcp_options_received *opt_rx,
+			    struct request_sock *req)
 {
 	struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
 	struct sock *nsk = sk_clone_lock(sk, GFP_ATOMIC);
@@ -1383,9 +1385,9 @@ struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req)
 
 	msk->write_seq = subflow_req->idsn + 1;
 	atomic64_set(&msk->snd_una, msk->write_seq);
-	if (subflow_req->remote_key_valid) {
+	if (opt_rx->mptcp.mp_capable) {
 		msk->can_ack = true;
-		msk->remote_key = subflow_req->remote_key;
+		msk->remote_key = opt_rx->mptcp.sndr_key;
 		mptcp_crypto_key_sha(msk->remote_key, NULL, &ack_seq);
 		ack_seq++;
 		msk->ack_seq = ack_seq;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index 67448002a2d7..a2b3048037d0 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -206,12 +206,10 @@ struct mptcp_subflow_request_sock {
 	struct	tcp_request_sock sk;
 	u16	mp_capable : 1,
 		mp_join : 1,
-		backup : 1,
-		remote_key_valid : 1;
+		backup : 1;
 	u8	local_id;
 	u8	remote_id;
 	u64	local_key;
-	u64	remote_key;
 	u64	idsn;
 	u32	token;
 	u32	ssn_offset;
@@ -332,7 +330,9 @@ void mptcp_proto_init(void);
 int mptcp_proto_v6_init(void);
 #endif
 
-struct sock *mptcp_sk_clone(const struct sock *sk, struct request_sock *req);
+struct sock *mptcp_sk_clone(const struct sock *sk,
+			    const struct tcp_options_received *opt_rx,
+			    struct request_sock *req);
 void mptcp_get_options(const struct sk_buff *skb,
 		       struct tcp_options_received *opt_rx);
 
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 10090ca3d3e0..87c094702d63 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -133,7 +133,6 @@ static void subflow_init_req(struct request_sock *req,
 
 	subflow_req->mp_capable = 0;
 	subflow_req->mp_join = 0;
-	subflow_req->remote_key_valid = 0;
 
 #ifdef CONFIG_TCP_MD5SIG
 	/* no MPTCP if MD5SIG is enabled on this socket or we may run out of
@@ -404,6 +403,7 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 
 	pr_debug("listener=%p, req=%p, conn=%p", listener, req, listener->conn);
 
+	opt_rx.mptcp.mp_capable = 0;
 	if (tcp_rsk(req)->is_mptcp == 0)
 		goto create_child;
 
@@ -418,18 +418,14 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 			goto create_msk;
 		}
 
-		opt_rx.mptcp.mp_capable = 0;
 		mptcp_get_options(skb, &opt_rx);
-		if (opt_rx.mptcp.mp_capable) {
-			subflow_req->remote_key = opt_rx.mptcp.sndr_key;
-			subflow_req->remote_key_valid = 1;
-		} else {
+		if (!opt_rx.mptcp.mp_capable) {
 			fallback = true;
 			goto create_child;
 		}
 
 create_msk:
-		new_msk = mptcp_sk_clone(listener->conn, req);
+		new_msk = mptcp_sk_clone(listener->conn, &opt_rx, req);
 		if (!new_msk)
 			fallback = true;
 	} else if (subflow_req->mp_join) {
@@ -473,6 +469,13 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 			mptcp_pm_new_connection(mptcp_sk(new_msk), 1);
 			ctx->conn = new_msk;
 			new_msk = NULL;
+
+			/* with OoO packets we can reach here without ingress
+			 * mpc option
+			 */
+			ctx->remote_key = opt_rx.mptcp.sndr_key;
+			ctx->fully_established = opt_rx.mptcp.mp_capable;
+			ctx->can_ack = opt_rx.mptcp.mp_capable;
 		} else if (ctx->mp_join) {
 			struct mptcp_sock *owner;
 
@@ -1152,9 +1155,6 @@ static void subflow_ulp_clone(const struct request_sock *req,
 		 * is fully established only after we receive the remote key
 		 */
 		new_ctx->mp_capable = 1;
-		new_ctx->fully_established = subflow_req->remote_key_valid;
-		new_ctx->can_ack = subflow_req->remote_key_valid;
-		new_ctx->remote_key = subflow_req->remote_key;
 		new_ctx->local_key = subflow_req->local_key;
 		new_ctx->token = subflow_req->token;
 		new_ctx->ssn_offset = subflow_req->ssn_offset;
-- 
2.21.1