mptcp: generate subflow hmac after mptcp_finish_join()

[ Upstream commit 0a4d8e96e4fd687af92b961d5cdcea0fdbde05fe ]

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>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index d6d8ad4f918e788b545aac96203c21fb3f0f7896..189139b8d401c676e34b39c8551f7e721bfd59cf 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -409,15 +409,15 @@ 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);