mptcp: generate subflow hmac after mptcp_finish_join()

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>

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index a50a97908866a7cd6a0da0e692ab789d5d9cc8af..2a58503e55bd39d01ea499b8624a2cfb8539b76c 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -430,15 +430,15 @@ 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);