Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index e9400ff..b2ccbc4 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
  *	Linux INET6 implementation
@@ -6,11 +7,6 @@
  *	Pedro Roque		<roque@di.fc.ul.pt>
  *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
  *
- *	This program 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 of the License, or (at your option) any later version.
- *
  *	Changes:
  * Roger Venning <r.venning@telstra.com>:	6to4 support
  * Nate Thompson <nate@thebog.net>:		6to4 support
@@ -534,19 +530,20 @@
 
 	if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 		ipv4_update_pmtu(skb, dev_net(skb->dev), info,
-				 t->parms.link, 0, iph->protocol, 0);
+				 t->parms.link, iph->protocol);
 		err = 0;
 		goto out;
 	}
 	if (type == ICMP_REDIRECT) {
-		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
-			      iph->protocol, 0);
+		ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
+			      iph->protocol);
 		err = 0;
 		goto out;
 	}
 
 	err = 0;
-	if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
+	if (__in6_dev_get(skb->dev) &&
+	    !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 		goto out;
 
 	if (t->parms.iph.daddr == 0)
@@ -668,6 +665,10 @@
 		    !net_eq(tunnel->net, dev_net(tunnel->dev))))
 			goto out;
 
+		/* skb can be uncloned in iptunnel_pull_header, so
+		 * old iph is no longer valid
+		 */
+		iph = (const struct iphdr *)skb_mac_header(skb);
 		err = IP_ECN_decapsulate(iph, skb);
 		if (unlikely(err)) {
 			if (log_ecn_error)
@@ -777,8 +778,9 @@
 		pbw0 = tunnel->ip6rd.prefixlen >> 5;
 		pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 
-		d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
-		    tunnel->ip6rd.relay_prefixlen;
+		d = tunnel->ip6rd.relay_prefixlen < 32 ?
+			(ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
+		    tunnel->ip6rd.relay_prefixlen : 0;
 
 		pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 		if (pbi1 > 0)
@@ -898,12 +900,17 @@
 			   RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
 			   0, dst, tiph->saddr, 0, 0,
 			   sock_net_uid(tunnel->net, NULL));
-	rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
 
-	if (IS_ERR(rt)) {
-		dev->stats.tx_carrier_errors++;
-		goto tx_error_icmp;
+	rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
+	if (!rt) {
+		rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
+		if (IS_ERR(rt)) {
+			dev->stats.tx_carrier_errors++;
+			goto tx_error_icmp;
+		}
+		dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
 	}
+
 	if (rt->rt_type != RTN_UNICAST) {
 		ip_rt_put(rt);
 		dev->stats.tx_carrier_errors++;
@@ -1021,6 +1028,9 @@
 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
 				   struct net_device *dev)
 {
+	if (!pskb_inet_may_pull(skb))
+		goto tx_err;
+
 	switch (skb->protocol) {
 	case htons(ETH_P_IP):
 		sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
@@ -1075,7 +1085,7 @@
 	if (!tdev && tunnel->parms.link)
 		tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
 
-	if (tdev) {
+	if (tdev && !netif_is_l3_master(tdev)) {
 		int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 
 		dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
@@ -1869,6 +1879,7 @@
 
 err_reg_dev:
 	ipip6_dev_free(sitn->fb_tunnel_dev);
+	free_netdev(sitn->fb_tunnel_dev);
 err_alloc_dev:
 	return err;
 }