Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5c36a99..4d2bcfc 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /* SCTP kernel implementation
  * Copyright (c) 1999-2000 Cisco, Inc.
  * Copyright (c) 1999-2001 Motorola, Inc.
@@ -10,22 +11,6 @@
  *
  * These functions handle all input from the IP layer into SCTP.
  *
- * This SCTP implementation is free software;
- * you can redistribute it and/or modify it under the terms of
- * the GNU General Public License as published by
- * the Free Software Foundation; either version 2, or (at your option)
- * any later version.
- *
- * This SCTP implementation is distributed in the hope that it
- * will be useful, but WITHOUT ANY WARRANTY; without even the implied
- *                 ************************
- * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
- * See the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with GNU CC; see the file COPYING.  If not, see
- * <http://www.gnu.org/licenses/>.
- *
  * Please send any bug reports or fixes you make to the
  * email address(es):
  *    lksctp developers <linux-sctp@vger.kernel.org>
@@ -57,6 +42,7 @@
 #include <net/sctp/checksum.h>
 #include <net/net_namespace.h>
 #include <linux/rhashtable.h>
+#include <net/sock_reuseport.h>
 
 /* Forward declarations for internal helpers. */
 static int sctp_rcv_ootb(struct sk_buff *);
@@ -65,8 +51,10 @@
 				      const union sctp_addr *paddr,
 				      const union sctp_addr *laddr,
 				      struct sctp_transport **transportp);
-static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
-						const union sctp_addr *laddr);
+static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
+					struct net *net, struct sk_buff *skb,
+					const union sctp_addr *laddr,
+					const union sctp_addr *daddr);
 static struct sctp_association *__sctp_lookup_association(
 					struct net *net,
 					const union sctp_addr *local,
@@ -171,7 +159,7 @@
 	asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
 
 	if (!asoc)
-		ep = __sctp_rcv_lookup_endpoint(net, &dest);
+		ep = __sctp_rcv_lookup_endpoint(net, skb, &dest, &src);
 
 	/* Retrieve the common input handling substructure. */
 	rcvr = asoc ? &asoc->base : &ep->base;
@@ -213,7 +201,7 @@
 
 	if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
 		goto discard_release;
-	nf_reset(skb);
+	nf_reset_ct(skb);
 
 	if (sk_filter(sk, skb))
 		goto discard_release;
@@ -255,7 +243,7 @@
 		bh_lock_sock(sk);
 	}
 
-	if (sock_owned_by_user(sk)) {
+	if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
 		if (sctp_add_backlog(sk, skb)) {
 			bh_unlock_sock(sk);
 			sctp_chunk_free(chunk);
@@ -333,8 +321,8 @@
 		local_bh_disable();
 		bh_lock_sock(sk);
 
-		if (sock_owned_by_user(sk)) {
-			if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
+		if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
+			if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
 				sctp_chunk_free(chunk);
 			else
 				backloged = 1;
@@ -348,7 +336,13 @@
 		if (backloged)
 			return 0;
 	} else {
-		sctp_inq_push(inqueue, chunk);
+		if (!sctp_newsk_ready(sk)) {
+			if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
+				return 0;
+			sctp_chunk_free(chunk);
+		} else {
+			sctp_inq_push(inqueue, chunk);
+		}
 	}
 
 done:
@@ -370,7 +364,7 @@
 	struct sctp_ep_common *rcvr = chunk->rcvr;
 	int ret;
 
-	ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
+	ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf));
 	if (!ret) {
 		/* Hold the assoc/ep while hanging on the backlog queue.
 		 * This way, we know structures we need will not disappear
@@ -574,7 +568,7 @@
  * is probably better.
  *
  */
-void sctp_v4_err(struct sk_buff *skb, __u32 info)
+int sctp_v4_err(struct sk_buff *skb, __u32 info)
 {
 	const struct iphdr *iph = (const struct iphdr *)skb->data;
 	const int ihlen = iph->ihl * 4;
@@ -599,7 +593,7 @@
 	skb->transport_header = savesctp;
 	if (!sk) {
 		__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-		return;
+		return -ENOENT;
 	}
 	/* Warning:  The sock lock is held.  Remember to call
 	 * sctp_err_finish!
@@ -653,6 +647,7 @@
 
 out_unlock:
 	sctp_err_finish(sk, transport);
+	return 0;
 }
 
 /*
@@ -720,43 +715,87 @@
 }
 
 /* Insert endpoint into the hash table.  */
-static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
+static int __sctp_hash_endpoint(struct sctp_endpoint *ep)
 {
-	struct net *net = sock_net(ep->base.sk);
-	struct sctp_ep_common *epb;
+	struct sock *sk = ep->base.sk;
+	struct net *net = sock_net(sk);
 	struct sctp_hashbucket *head;
+	struct sctp_ep_common *epb;
 
 	epb = &ep->base;
-
 	epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
 	head = &sctp_ep_hashtable[epb->hashent];
 
+	if (sk->sk_reuseport) {
+		bool any = sctp_is_ep_boundall(sk);
+		struct sctp_ep_common *epb2;
+		struct list_head *list;
+		int cnt = 0, err = 1;
+
+		list_for_each(list, &ep->base.bind_addr.address_list)
+			cnt++;
+
+		sctp_for_each_hentry(epb2, &head->chain) {
+			struct sock *sk2 = epb2->sk;
+
+			if (!net_eq(sock_net(sk2), net) || sk2 == sk ||
+			    !uid_eq(sock_i_uid(sk2), sock_i_uid(sk)) ||
+			    !sk2->sk_reuseport)
+				continue;
+
+			err = sctp_bind_addrs_check(sctp_sk(sk2),
+						    sctp_sk(sk), cnt);
+			if (!err) {
+				err = reuseport_add_sock(sk, sk2, any);
+				if (err)
+					return err;
+				break;
+			} else if (err < 0) {
+				return err;
+			}
+		}
+
+		if (err) {
+			err = reuseport_alloc(sk, any);
+			if (err)
+				return err;
+		}
+	}
+
 	write_lock(&head->lock);
 	hlist_add_head(&epb->node, &head->chain);
 	write_unlock(&head->lock);
+	return 0;
 }
 
 /* Add an endpoint to the hash. Local BH-safe. */
-void sctp_hash_endpoint(struct sctp_endpoint *ep)
+int sctp_hash_endpoint(struct sctp_endpoint *ep)
 {
+	int err;
+
 	local_bh_disable();
-	__sctp_hash_endpoint(ep);
+	err = __sctp_hash_endpoint(ep);
 	local_bh_enable();
+
+	return err;
 }
 
 /* Remove endpoint from the hash table.  */
 static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
 {
-	struct net *net = sock_net(ep->base.sk);
+	struct sock *sk = ep->base.sk;
 	struct sctp_hashbucket *head;
 	struct sctp_ep_common *epb;
 
 	epb = &ep->base;
 
-	epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
+	epb->hashent = sctp_ep_hashfn(sock_net(sk), epb->bind_addr.port);
 
 	head = &sctp_ep_hashtable[epb->hashent];
 
+	if (rcu_access_pointer(sk->sk_reuseport_cb))
+		reuseport_detach_sock(sk);
+
 	write_lock(&head->lock);
 	hlist_del_init(&epb->node);
 	write_unlock(&head->lock);
@@ -770,16 +809,35 @@
 	local_bh_enable();
 }
 
+static inline __u32 sctp_hashfn(const struct net *net, __be16 lport,
+				const union sctp_addr *paddr, __u32 seed)
+{
+	__u32 addr;
+
+	if (paddr->sa.sa_family == AF_INET6)
+		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
+	else
+		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
+
+	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
+			     (__force __u32)lport, net_hash_mix(net), seed);
+}
+
 /* Look up an endpoint. */
-static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
-						const union sctp_addr *laddr)
+static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(
+					struct net *net, struct sk_buff *skb,
+					const union sctp_addr *laddr,
+					const union sctp_addr *paddr)
 {
 	struct sctp_hashbucket *head;
 	struct sctp_ep_common *epb;
 	struct sctp_endpoint *ep;
+	struct sock *sk;
+	__be16 lport;
 	int hash;
 
-	hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
+	lport = laddr->v4.sin_port;
+	hash = sctp_ep_hashfn(net, ntohs(lport));
 	head = &sctp_ep_hashtable[hash];
 	read_lock(&head->lock);
 	sctp_for_each_hentry(epb, &head->chain) {
@@ -791,6 +849,15 @@
 	ep = sctp_sk(net->sctp.ctl_sock)->ep;
 
 hit:
+	sk = ep->base.sk;
+	if (sk->sk_reuseport) {
+		__u32 phash = sctp_hashfn(net, lport, paddr, 0);
+
+		sk = reuseport_select_sock(sk, phash, skb,
+					   sizeof(struct sctphdr));
+		if (sk)
+			ep = sctp_sk(sk)->ep;
+	}
 	sctp_endpoint_hold(ep);
 	read_unlock(&head->lock);
 	return ep;
@@ -815,7 +882,7 @@
 	if (!sctp_transport_hold(t))
 		return err;
 
-	if (!net_eq(sock_net(t->asoc->base.sk), x->net))
+	if (!net_eq(t->asoc->base.net, x->net))
 		goto out;
 	if (x->lport != htons(t->asoc->base.bind_addr.port))
 		goto out;
@@ -829,35 +896,17 @@
 static inline __u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
 {
 	const struct sctp_transport *t = data;
-	const union sctp_addr *paddr = &t->ipaddr;
-	const struct net *net = sock_net(t->asoc->base.sk);
-	__be16 lport = htons(t->asoc->base.bind_addr.port);
-	__u32 addr;
 
-	if (paddr->sa.sa_family == AF_INET6)
-		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
-	else
-		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
-
-	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
-			     (__force __u32)lport, net_hash_mix(net), seed);
+	return sctp_hashfn(t->asoc->base.net,
+			   htons(t->asoc->base.bind_addr.port),
+			   &t->ipaddr, seed);
 }
 
 static inline __u32 sctp_hash_key(const void *data, u32 len, u32 seed)
 {
 	const struct sctp_hash_cmp_arg *x = data;
-	const union sctp_addr *paddr = x->paddr;
-	const struct net *net = x->net;
-	__be16 lport = x->lport;
-	__u32 addr;
 
-	if (paddr->sa.sa_family == AF_INET6)
-		addr = jhash(&paddr->v6.sin6_addr, 16, seed);
-	else
-		addr = (__force __u32)paddr->v4.sin_addr.s_addr;
-
-	return  jhash_3words(addr, ((__force __u32)paddr->v4.sin_port) << 16 |
-			     (__force __u32)lport, net_hash_mix(net), seed);
+	return sctp_hashfn(x->net, x->lport, x->paddr, seed);
 }
 
 static const struct rhashtable_params sctp_hash_params = {