1 files changed, 105 insertions, 83 deletions

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index fd021cf8286e..86ce58ae533d 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -247,6 +247,7 @@ again:
 
 		if (unlikely(req->syncookie)) {
 			if (!mptcp_can_accept_new_subflow(subflow_req->msk)) {
+				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINREJECTED);
 				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
 				return -EPERM;
 			}
@@ -490,6 +491,9 @@ static void subflow_set_remote_key(struct mptcp_sock *msk,
 	mptcp_crypto_key_sha(subflow->remote_key, NULL, &subflow->iasn);
 	subflow->iasn++;
 
+	/* for fallback's sake */
+	subflow->map_seq = subflow->iasn;
+
 	WRITE_ONCE(msk->remote_key, subflow->remote_key);
 	WRITE_ONCE(msk->ack_seq, subflow->iasn);
 	WRITE_ONCE(msk->can_ack, true);
@@ -543,10 +547,13 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
 	mptcp_get_options(skb, &mp_opt);
 	if (subflow->request_mptcp) {
 		if (!(mp_opt.suboptions & OPTION_MPTCP_MPC_SYNACK)) {
-			MPTCP_INC_STATS(sock_net(sk),
-					MPTCP_MIB_MPCAPABLEACTIVEFALLBACK);
-			mptcp_do_fallback(sk);
-			pr_fallback(msk);
+			if (!mptcp_try_fallback(sk,
+						MPTCP_MIB_MPCAPABLEACTIVEFALLBACK)) {
+				MPTCP_INC_STATS(sock_net(sk),
+						MPTCP_MIB_FALLBACKFAILED);
+				goto do_reset;
+			}
+
 			goto fallback;
 		}
 
@@ -745,17 +752,11 @@ struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *op
 EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc);
 
 /* validate hmac received in third ACK */
-static bool subflow_hmac_valid(const struct request_sock *req,
+static bool subflow_hmac_valid(const struct mptcp_subflow_request_sock *subflow_req,
 			       const struct mptcp_options_received *mp_opt)
 {
-	const struct mptcp_subflow_request_sock *subflow_req;
+	struct mptcp_sock *msk = subflow_req->msk;
 	u8 hmac[SHA256_DIGEST_SIZE];
-	struct mptcp_sock *msk;
-
-	subflow_req = mptcp_subflow_rsk(req);
-	msk = subflow_req->msk;
-	if (!msk)
-		return false;
 
 	subflow_generate_hmac(READ_ONCE(msk->remote_key),
 			      READ_ONCE(msk->local_key),
@@ -802,9 +803,6 @@ void __mptcp_subflow_fully_established(struct mptcp_sock *msk,
 	subflow_set_remote_key(msk, subflow, mp_opt);
 	WRITE_ONCE(subflow->fully_established, true);
 	WRITE_ONCE(msk->fully_established, true);
-
-	if (subflow->is_mptfo)
-		__mptcp_fastopen_gen_msk_ackseq(msk, subflow, mp_opt);
 }
 
 static struct sock *subflow_syn_recv_sock(const struct sock *sk,
@@ -853,12 +851,8 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
 
 	} else if (subflow_req->mp_join) {
 		mptcp_get_options(skb, &mp_opt);
-		if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK) ||
-		    !subflow_hmac_valid(req, &mp_opt) ||
-		    !mptcp_can_accept_new_subflow(subflow_req->msk)) {
-			SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
+		if (!(mp_opt.suboptions & OPTION_MPTCP_MPJ_ACK))
 			fallback = true;
-		}
 	}
 
 create_child:
@@ -892,6 +886,10 @@ create_child:
 
 			ctx->subflow_id = 1;
 			owner = mptcp_sk(ctx->conn);
+
+			if (mp_opt.deny_join_id0)
+				WRITE_ONCE(owner->pm.remote_deny_join_id0, true);
+
 			mptcp_pm_new_connection(owner, child, 1);
 
 			/* with OoO packets we can reach here without ingress
@@ -908,6 +906,18 @@ create_child:
 				goto dispose_child;
 			}
 
+			if (!subflow_hmac_valid(subflow_req, &mp_opt)) {
+				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
+				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
+				goto dispose_child;
+			}
+
+			if (!mptcp_can_accept_new_subflow(owner)) {
+				SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINREJECTED);
+				subflow_add_reset_reason(skb, MPTCP_RST_EPROHIBIT);
+				goto dispose_child;
+			}
+
 			/* move the msk reference ownership to the subflow */
 			subflow_req->msk = NULL;
 			ctx->conn = (struct sock *)owner;
@@ -1142,7 +1152,6 @@ static enum mapping_status get_mapping_status(struct sock *ssk,
 	if (data_len == 0) {
 		pr_debug("infinite mapping received\n");
 		MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPRX);
-		subflow->map_data_len = 0;
 		return MAPPING_INVALID;
 	}
 
@@ -1271,9 +1280,15 @@ out:
 		subflow->map_valid = 0;
 }
 
-/* sched mptcp worker to remove the subflow if no more data is pending */
+static bool subflow_is_done(const struct sock *sk)
+{
+	return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
+}
+
+/* sched mptcp worker for subflow cleanup if no more data is pending */
 static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ssk)
 {
+	const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 	struct sock *sk = (struct sock *)msk;
 
 	if (likely(ssk->sk_state != TCP_CLOSE &&
@@ -1281,37 +1296,45 @@ static void subflow_sched_work_if_closed(struct mptcp_sock *msk, struct sock *ss
 		    inet_sk_state_load(sk) != TCP_ESTABLISHED)))
 		return;
 
-	if (skb_queue_empty(&ssk->sk_receive_queue) &&
-	    !test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
-		mptcp_schedule_work(sk);
-}
+	if (!skb_queue_empty(&ssk->sk_receive_queue))
+		return;
 
-static bool subflow_can_fallback(struct mptcp_subflow_context *subflow)
-{
-	struct mptcp_sock *msk = mptcp_sk(subflow->conn);
+	if (!test_and_set_bit(MPTCP_WORK_CLOSE_SUBFLOW, &msk->flags))
+		mptcp_schedule_work(sk);
 
-	if (subflow->mp_join)
-		return false;
-	else if (READ_ONCE(msk->csum_enabled))
-		return !subflow->valid_csum_seen;
-	else
-		return READ_ONCE(msk->allow_infinite_fallback);
+	/* when the fallback subflow closes the rx side, trigger a 'dummy'
+	 * ingress data fin, so that the msk state will follow along
+	 */
+	if (__mptcp_check_fallback(msk) && subflow_is_done(ssk) &&
+	    msk->first == ssk &&
+	    mptcp_update_rcv_data_fin(msk, subflow->map_seq +
+				      subflow->map_data_len, true))
+		mptcp_schedule_work(sk);
 }
 
-static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk)
+static bool mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
 	unsigned long fail_tout;
 
+	/* we are really failing, prevent any later subflow join */
+	spin_lock_bh(&msk->fallback_lock);
+	if (!msk->allow_infinite_fallback) {
+		spin_unlock_bh(&msk->fallback_lock);
+		return false;
+	}
+	msk->allow_subflows = false;
+	spin_unlock_bh(&msk->fallback_lock);
+
 	/* graceful failure can happen only on the MPC subflow */
 	if (WARN_ON_ONCE(ssk != READ_ONCE(msk->first)))
-		return;
+		return false;
 
 	/* since the close timeout take precedence on the fail one,
 	 * no need to start the latter when the first is already set
 	 */
 	if (sock_flag((struct sock *)msk, SOCK_DEAD))
-		return;
+		return true;
 
 	/* we don't need extreme accuracy here, use a zero fail_tout as special
 	 * value meaning no fail timeout at all;
@@ -1323,6 +1346,7 @@ static void mptcp_subflow_fail(struct mptcp_sock *msk, struct sock *ssk)
 	tcp_send_ack(ssk);
 
 	mptcp_reset_tout_timer(msk, subflow->fail_tout);
+	return true;
 }
 
 static bool subflow_check_data_avail(struct sock *ssk)
@@ -1383,17 +1407,16 @@ fallback:
 		    (subflow->mp_join || subflow->valid_csum_seen)) {
 			subflow->send_mp_fail = 1;
 
-			if (!READ_ONCE(msk->allow_infinite_fallback)) {
+			if (!mptcp_subflow_fail(msk, ssk)) {
 				subflow->reset_transient = 0;
 				subflow->reset_reason = MPTCP_RST_EMIDDLEBOX;
 				goto reset;
 			}
-			mptcp_subflow_fail(msk, ssk);
 			WRITE_ONCE(subflow->data_avail, true);
 			return true;
 		}
 
-		if (!subflow_can_fallback(subflow) && subflow->map_data_len) {
+		if (!mptcp_try_fallback(ssk, MPTCP_MIB_DSSFALLBACK)) {
 			/* fatal protocol error, close the socket.
 			 * subflow_error_report() will introduce the appropriate barriers
 			 */
@@ -1411,15 +1434,16 @@ reset:
 			WRITE_ONCE(subflow->data_avail, false);
 			return false;
 		}
-
-		mptcp_do_fallback(ssk);
 	}
 
 	skb = skb_peek(&ssk->sk_receive_queue);
 	subflow->map_valid = 1;
-	subflow->map_seq = READ_ONCE(msk->ack_seq);
 	subflow->map_data_len = skb->len;
 	subflow->map_subflow_seq = tcp_sk(ssk)->copied_seq - subflow->ssn_offset;
+	subflow->map_seq = __mptcp_expand_seq(subflow->map_seq,
+					      subflow->iasn +
+					      TCP_SKB_CB(skb)->seq -
+					      subflow->ssn_offset - 1);
 	WRITE_ONCE(subflow->data_avail, true);
 	return true;
 }
@@ -1644,7 +1668,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 		addrlen = sizeof(struct sockaddr_in6);
 #endif
 	ssk->sk_bound_dev_if = local->ifindex;
-	err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
+	err = kernel_bind(sf, (struct sockaddr_unsized *)&addr, addrlen);
 	if (err) {
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTXBINDERR);
 		pr_debug("msk=%p local=%d remote=%d bind error: %d\n",
@@ -1664,7 +1688,7 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 
 	sock_hold(ssk);
 	list_add_tail(&subflow->node, &msk->conn_list);
-	err = kernel_connect(sf, (struct sockaddr *)&addr, addrlen, O_NONBLOCK);
+	err = kernel_connect(sf, (struct sockaddr_unsized *)&addr, addrlen, O_NONBLOCK);
 	if (err && err != -EINPROGRESS) {
 		MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNTXCONNECTERR);
 		pr_debug("msk=%p local=%d remote=%d connect error: %d\n",
@@ -1677,7 +1701,6 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_pm_local *local,
 	/* discard the subflow socket */
 	mptcp_sock_graft(ssk, sk->sk_socket);
 	iput(SOCK_INODE(sf));
-	WRITE_ONCE(msk->allow_infinite_fallback, false);
 	mptcp_stop_tout_timer(sk);
 	return 0;
 
@@ -1697,30 +1720,39 @@ err_out:
 	return err;
 }
 
-static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
+void __mptcp_inherit_memcg(struct sock *sk, struct sock *ssk, gfp_t gfp)
+{
+	/* Only if the msk has been accepted already (and not orphaned).*/
+	if (!mem_cgroup_sockets_enabled || !sk->sk_socket)
+		return;
+
+	mem_cgroup_sk_inherit(sk, ssk);
+	__sk_charge(ssk, gfp);
+}
+
+void __mptcp_inherit_cgrp_data(struct sock *sk, struct sock *ssk)
 {
 #ifdef CONFIG_SOCK_CGROUP_DATA
-	struct sock_cgroup_data *parent_skcd = &parent->sk_cgrp_data,
-				*child_skcd = &child->sk_cgrp_data;
+	struct sock_cgroup_data *sk_cd = &sk->sk_cgrp_data,
+				*ssk_cd = &ssk->sk_cgrp_data;
 
 	/* only the additional subflows created by kworkers have to be modified */
-	if (cgroup_id(sock_cgroup_ptr(parent_skcd)) !=
-	    cgroup_id(sock_cgroup_ptr(child_skcd))) {
-#ifdef CONFIG_MEMCG
-		struct mem_cgroup *memcg = parent->sk_memcg;
-
-		mem_cgroup_sk_free(child);
-		if (memcg && css_tryget(&memcg->css))
-			child->sk_memcg = memcg;
-#endif /* CONFIG_MEMCG */
-
-		cgroup_sk_free(child_skcd);
-		*child_skcd = *parent_skcd;
-		cgroup_sk_clone(child_skcd);
+	if (cgroup_id(sock_cgroup_ptr(sk_cd)) !=
+	    cgroup_id(sock_cgroup_ptr(ssk_cd))) {
+		cgroup_sk_free(ssk_cd);
+		*ssk_cd = *sk_cd;
+		cgroup_sk_clone(sk_cd);
 	}
 #endif /* CONFIG_SOCK_CGROUP_DATA */
 }
 
+static void mptcp_attach_cgroup(struct sock *parent, struct sock *child)
+{
+	__mptcp_inherit_cgrp_data(parent, child);
+	if (mem_cgroup_sockets_enabled)
+		mem_cgroup_sk_inherit(parent, child);
+}
+
 static void mptcp_subflow_ops_override(struct sock *ssk)
 {
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
@@ -1772,10 +1804,7 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
 	 * needs it.
 	 * Update ns_tracker to current stack trace and refcounted tracker.
 	 */
-	__netns_tracker_free(net, &sf->sk->ns_tracker, false);
-	sf->sk->sk_net_refcnt = 1;
-	get_net_track(net, &sf->sk->ns_tracker, GFP_KERNEL);
-	sock_inuse_add(net, 1);
+	sk_net_refcnt_upgrade(sf->sk);
 	err = tcp_set_ulp(sf->sk, "mptcp");
 	if (err)
 		goto err_free;
@@ -1842,23 +1871,15 @@ static void __subflow_state_change(struct sock *sk)
 	rcu_read_unlock();
 }
 
-static bool subflow_is_done(const struct sock *sk)
-{
-	return sk->sk_shutdown & RCV_SHUTDOWN || sk->sk_state == TCP_CLOSE;
-}
-
 static void subflow_state_change(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
 	struct sock *parent = subflow->conn;
-	struct mptcp_sock *msk;
 
 	__subflow_state_change(sk);
 
-	msk = mptcp_sk(parent);
 	if (subflow_simultaneous_connect(sk)) {
-		mptcp_do_fallback(sk);
-		pr_fallback(msk);
+		WARN_ON_ONCE(!mptcp_try_fallback(sk, MPTCP_MIB_SIMULTCONNFALLBACK));
 		subflow->conn_finished = 1;
 		mptcp_propagate_state(parent, sk, subflow, NULL);
 	}
@@ -1873,13 +1894,6 @@ static void subflow_state_change(struct sock *sk)
 		subflow_error_report(sk);
 
 	subflow_sched_work_if_closed(mptcp_sk(parent), sk);
-
-	/* when the fallback subflow closes the rx side, trigger a 'dummy'
-	 * ingress data fin, so that the msk state will follow along
-	 */
-	if (__mptcp_check_fallback(msk) && subflow_is_done(sk) && msk->first == sk &&
-	    mptcp_update_rcv_data_fin(msk, READ_ONCE(msk->ack_seq), true))
-		mptcp_schedule_work(parent);
 }
 
 void mptcp_subflow_queue_clean(struct sock *listener_sk, struct sock *listener_ssk)
@@ -2152,6 +2166,10 @@ void __init mptcp_subflow_init(void)
 	tcp_prot_override = tcp_prot;
 	tcp_prot_override.release_cb = tcp_release_cb_override;
 	tcp_prot_override.diag_destroy = tcp_abort_override;
+#ifdef CONFIG_BPF_SYSCALL
+	/* Disable sockmap processing for subflows */
+	tcp_prot_override.psock_update_sk_prot = NULL;
+#endif
 
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 	/* In struct mptcp_subflow_request_sock, we assume the TCP request sock
@@ -2188,6 +2206,10 @@ void __init mptcp_subflow_init(void)
 	tcpv6_prot_override = tcpv6_prot;
 	tcpv6_prot_override.release_cb = tcp_release_cb_override;
 	tcpv6_prot_override.diag_destroy = tcp_abort_override;
+#ifdef CONFIG_BPF_SYSCALL
+	/* Disable sockmap processing for subflows */
+	tcpv6_prot_override.psock_update_sk_prot = NULL;
+#endif
 #endif
 
 	mptcp_diag_subflow_init(&subflow_ulp_ops);