commit 030d37bd1cd2443a1f21db47eb301899bfa45a2a
author Jianguo Wu <wujianguo@chinatelecom.cn> Fri Jul 09 17:20:47 2021 -0700
committer David S. Miller <davem@davemloft.net> Fri Jul 09 18:38:53 2021 -0700
tree cb98cd26b301fa768e7db75852af276457da4cca
parent 0c71929b5893e410e0efbe1bbeca6f19a5f19956

mptcp: remove redundant req destruct in subflow_check_req()

In subflow_check_req(), if subflow sport is mismatch, will put msk,
destroy token, and destruct req, then return -EPERM, which can be
done by subflow_req_destructor() via:

  tcp_conn_request()
    |--__reqsk_free()
      |--subflow_req_destructor()

So we should remove these redundant code, otherwise will call
tcp_v4_reqsk_destructor() twice, and may double free
inet_rsk(req)->ireq_opt.

Fixes: 5bc56388c74f ("mptcp: add port number check for MP_JOIN")
Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mptcp/subflow.c

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 66d0b18..b15e201 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -214,11 +214,6 @@ static int subflow_check_req(struct request_sock *req,
 				 ntohs(inet_sk(sk_listener)->inet_sport),
 				 ntohs(inet_sk((struct sock *)subflow_req->msk)->inet_sport));
 			if (!mptcp_pm_sport_in_anno_list(subflow_req->msk, sk_listener)) {
-				sock_put((struct sock *)subflow_req->msk);
-				mptcp_token_destroy_request(req);
-				tcp_request_sock_ops.destructor(req);
-				subflow_req->msk = NULL;
-				subflow_req->mp_join = 0;
 				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MISMATCHPORTSYNRX);
 				return -EPERM;
 			}