Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3f83ea8..575bd0f 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -95,7 +95,8 @@
 static int		ip6_pkt_prohibit_out(struct net *net, struct sock *sk, struct sk_buff *skb);
 static void		ip6_link_failure(struct sk_buff *skb);
 static void		ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
-					   struct sk_buff *skb, u32 mtu);
+					   struct sk_buff *skb, u32 mtu,
+					   bool confirm_neigh);
 static void		rt6_do_redirect(struct dst_entry *dst, struct sock *sk,
 					struct sk_buff *skb);
 static int rt6_score_route(const struct fib6_nh *nh, u32 fib6_flags, int oif,
@@ -264,7 +265,8 @@
 }
 
 static void ip6_rt_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
-					 struct sk_buff *skb, u32 mtu)
+					 struct sk_buff *skb, u32 mtu,
+					 bool confirm_neigh)
 {
 }
 
@@ -429,9 +431,12 @@
 	struct fib6_info *sibling, *next_sibling;
 	struct fib6_info *match = res->f6i;
 
-	if ((!match->fib6_nsiblings && !match->nh) || have_oif_match)
+	if (!match->nh && (!match->fib6_nsiblings || have_oif_match))
 		goto out;
 
+	if (match->nh && have_oif_match && res->nh)
+		return;
+
 	/* We might have already computed the hash for ICMPv6 errors. In such
 	 * case it will always be non-zero. Otherwise now is the time to do it.
 	 */
@@ -1386,9 +1391,18 @@
 	}
 	ip6_rt_copy_init(pcpu_rt, res);
 	pcpu_rt->rt6i_flags |= RTF_PCPU;
+
+	if (f6i->nh)
+		pcpu_rt->sernum = rt_genid_ipv6(dev_net(dev));
+
 	return pcpu_rt;
 }
 
+static bool rt6_is_valid(const struct rt6_info *rt6)
+{
+	return rt6->sernum == rt_genid_ipv6(dev_net(rt6->dst.dev));
+}
+
 /* It should be called with rcu_read_lock() acquired */
 static struct rt6_info *rt6_get_pcpu_route(const struct fib6_result *res)
 {
@@ -1396,6 +1410,19 @@
 
 	pcpu_rt = this_cpu_read(*res->nh->rt6i_pcpu);
 
+	if (pcpu_rt && pcpu_rt->sernum && !rt6_is_valid(pcpu_rt)) {
+		struct rt6_info *prev, **p;
+
+		p = this_cpu_ptr(res->nh->rt6i_pcpu);
+		prev = xchg(p, NULL);
+		if (prev) {
+			dst_dev_put(&prev->dst);
+			dst_release(&prev->dst);
+		}
+
+		pcpu_rt = NULL;
+	}
+
 	return pcpu_rt;
 }
 
@@ -1640,6 +1667,7 @@
 	struct in6_addr *src_key = NULL;
 	struct rt6_exception *rt6_ex;
 	struct fib6_nh *nh = res->nh;
+	int max_depth;
 	int err = 0;
 
 	spin_lock_bh(&rt6_exception_lock);
@@ -1694,7 +1722,9 @@
 	bucket->depth++;
 	net->ipv6.rt6_stats->fib_rt_cache++;
 
-	if (bucket->depth > FIB6_MAX_DEPTH)
+	/* Randomize max depth to avoid some side channels attacks. */
+	max_depth = FIB6_MAX_DEPTH + prandom_u32_max(FIB6_MAX_DEPTH);
+	while (bucket->depth > max_depth)
 		rt6_exception_remove_oldest(bucket);
 
 out:
@@ -2597,6 +2627,9 @@
 
 	rt = container_of(dst, struct rt6_info, dst);
 
+	if (rt->sernum)
+		return rt6_is_valid(rt) ? dst : NULL;
+
 	rcu_read_lock();
 
 	/* All IPV6 dsts are created with ->obsolete set to the value
@@ -2695,13 +2728,16 @@
 }
 
 static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk,
-				 const struct ipv6hdr *iph, u32 mtu)
+				 const struct ipv6hdr *iph, u32 mtu,
+				 bool confirm_neigh)
 {
 	const struct in6_addr *daddr, *saddr;
 	struct rt6_info *rt6 = (struct rt6_info *)dst;
 
-	if (dst_metric_locked(dst, RTAX_MTU))
-		return;
+	/* Note: do *NOT* check dst_metric_locked(dst, RTAX_MTU)
+	 * IPv6 pmtu discovery isn't optional, so 'mtu lock' cannot disable it.
+	 * [see also comment in rt6_mtu_change_route()]
+	 */
 
 	if (iph) {
 		daddr = &iph->daddr;
@@ -2713,7 +2749,10 @@
 		daddr = NULL;
 		saddr = NULL;
 	}
-	dst_confirm_neigh(dst, daddr);
+
+	if (confirm_neigh)
+		dst_confirm_neigh(dst, daddr);
+
 	mtu = max_t(u32, mtu, IPV6_MIN_MTU);
 	if (mtu >= dst_mtu(dst))
 		return;
@@ -2767,9 +2806,11 @@
 }
 
 static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
-			       struct sk_buff *skb, u32 mtu)
+			       struct sk_buff *skb, u32 mtu,
+			       bool confirm_neigh)
 {
-	__ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu);
+	__ip6_rt_update_pmtu(dst, sk, skb ? ipv6_hdr(skb) : NULL, mtu,
+			     confirm_neigh);
 }
 
 void ip6_update_pmtu(struct sk_buff *skb, struct net *net, __be32 mtu,
@@ -2788,7 +2829,7 @@
 
 	dst = ip6_route_output(net, NULL, &fl6);
 	if (!dst->error)
-		__ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu));
+		__ip6_rt_update_pmtu(dst, NULL, iph, ntohl(mtu), true);
 	dst_release(dst);
 }
 EXPORT_SYMBOL_GPL(ip6_update_pmtu);
@@ -3371,7 +3412,7 @@
 	if ((flags & RTF_REJECT) ||
 	    (dev && (dev->flags & IFF_LOOPBACK) &&
 	     !(addr_type & IPV6_ADDR_LOOPBACK) &&
-	     !(flags & RTF_LOCAL)))
+	     !(flags & (RTF_ANYCAST | RTF_LOCAL))))
 		return true;
 
 	return false;
@@ -3617,7 +3658,7 @@
 		err = PTR_ERR(rt->fib6_metrics);
 		/* Do not leave garbage there. */
 		rt->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
-		goto out;
+		goto out_free;
 	}
 
 	if (cfg->fc_flags & RTF_ADDRCONF)
@@ -3648,13 +3689,13 @@
 	rt->fib6_src.plen = cfg->fc_src_len;
 #endif
 	if (nh) {
-		if (!nexthop_get(nh)) {
-			NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
-			goto out;
-		}
 		if (rt->fib6_src.plen) {
 			NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
-			goto out;
+			goto out_free;
+		}
+		if (!nexthop_get(nh)) {
+			NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
+			goto out_free;
 		}
 		rt->nh = nh;
 		fib6_nh = nexthop_fib6_nh(rt->nh);
@@ -3691,6 +3732,10 @@
 out:
 	fib6_info_release(rt);
 	return ERR_PTR(err);
+out_free:
+	ip_fib_metrics_put(rt->fib6_metrics);
+	kfree(rt);
+	return ERR_PTR(err);
 }
 
 int ip6_route_add(struct fib6_config *cfg, gfp_t gfp_flags,
@@ -5145,8 +5190,11 @@
 		 * nexthops have been replaced by first new, the rest should
 		 * be added to it.
 		 */
-		cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL |
-						     NLM_F_REPLACE);
+		if (cfg->fc_nlinfo.nlh) {
+			cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL |
+							     NLM_F_REPLACE);
+			cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE;
+		}
 		nhn++;
 	}