1 files changed, 25 insertions, 4 deletions

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 966f777d35ce..54b7ffc21861 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -435,10 +435,12 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 			goto do_reset;
 		}
 
+		subflow->backup = mp_opt.backup;
 		subflow->thmac = mp_opt.thmac;
 		subflow->remote_nonce = mp_opt.nonce;
-		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
-			 subflow->thmac, subflow->remote_nonce);
+		pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u backup=%d",
+			 subflow, subflow->thmac, subflow->remote_nonce,
+			 subflow->backup);
 
 		if (!subflow_thmac_valid(subflow)) {
 			MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINACKMAC);
@@ -908,6 +910,8 @@ static enum mapping_status validate_data_csum(struct sock *ssk, struct sk_buff *
 	csum = csum_partial(&header, sizeof(header), subflow->map_data_csum);
 	if (unlikely(csum_fold(csum))) {
 		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_DATACSUMERR);
+		subflow->send_mp_fail = 1;
+		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_MPFAILTX);
 		return subflow->mp_join ? MAPPING_INVALID : MAPPING_DUMMY;
 	}
 
@@ -1155,6 +1159,20 @@ no_data:
 
 fallback:
 	/* RFC 8684 section 3.7. */
+	if (subflow->send_mp_fail) {
+		if (mptcp_has_another_subflow(ssk)) {
+			while ((skb = skb_peek(&ssk->sk_receive_queue)))
+				sk_eat_skb(ssk, skb);
+		}
+		ssk->sk_err = EBADMSG;
+		tcp_set_state(ssk, TCP_CLOSE);
+		subflow->reset_transient = 0;
+		subflow->reset_reason = MPTCP_RST_EMIDDLEBOX;
+		tcp_send_active_reset(ssk, GFP_ATOMIC);
+		WRITE_ONCE(subflow->data_avail, 0);
+		return true;
+	}
+
 	if (subflow->mp_join || subflow->fully_established) {
 		/* fatal protocol error, close the socket.
 		 * subflow_error_report() will introduce the appropriate barriers
@@ -1353,8 +1371,7 @@ void mptcp_info2sockaddr(const struct mptcp_addr_info *info,
 }
 
 int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
-			    const struct mptcp_addr_info *remote,
-			    u8 flags, int ifindex)
+			    const struct mptcp_addr_info *remote)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_subflow_context *subflow;
@@ -1365,6 +1382,8 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 	struct sock *ssk;
 	u32 remote_token;
 	int addrlen;
+	int ifindex;
+	u8 flags;
 	int err;
 
 	if (!mptcp_is_fully_established(sk))
@@ -1388,6 +1407,8 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
 		local_id = err;
 	}
 
+	mptcp_pm_get_flags_and_ifindex_by_id(sock_net(sk), local_id,
+					     &flags, &ifindex);
 	subflow->remote_key = msk->remote_key;
 	subflow->local_key = msk->local_key;
 	subflow->token = msk->token;