[PATCH] mptcp: generate subflow hmac after mptcp_finish_join()

[Jianguo Wu <wujianguo106@163.com>]

From: Jianguo Wu <wujianguo@chinatelecom.cn>

For outgoing subflow join, when recv SYNACK, in subflow_finish_connect(),
the mptcp_finish_join() may return false in some cases, and send a RESET
to remote, and no local hmac is required.
So generate subflow hmac after mptcp_finish_join().

Fixes: ec3edaa7ca6c ("mptcp: Add handling of outgoing MP_JOIN requests").
Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
---
 net/mptcp/subflow.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index c896803..554e7cce 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -433,15 +433,15 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 			goto do_reset;
 		}

+		if (!mptcp_finish_join(sk))
+			goto do_reset;
+
 		subflow_generate_hmac(subflow->local_key, subflow->remote_key,
 				      subflow->local_nonce,
 				      subflow->remote_nonce,
 				      hmac);
 		memcpy(subflow->hmac, hmac, MPTCPOPT_HMAC_LEN);

-		if (!mptcp_finish_join(sk))
-			goto do_reset;
-
 		subflow->mp_join = 1;
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);

-- 
1.8.3.1