4 files changed, 37 insertions, 17 deletions

diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index fb3f809e34e4..751d051f0bc7 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -179,6 +179,7 @@ __be32 inet_confirm_addr(struct net *net, struct in_device *in_dev, __be32 dst,
 			 __be32 local, int scope);
 struct in_ifaddr *inet_ifa_byprefix(struct in_device *in_dev, __be32 prefix,
 				    __be32 mask);
+struct in_ifaddr *inet_lookup_ifaddr_rcu(struct net *net, __be32 addr);
 static __inline__ bool inet_ifa_match(__be32 addr, struct in_ifaddr *ifa)
 {
 	return !((addr^ifa->ifa_address)&ifa->ifa_mask);
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 20d061c805e3..20720721da4b 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -49,6 +49,7 @@ struct netns_ipv4 {
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 	struct fib_rules_ops	*rules_ops;
 	bool			fib_has_custom_rules;
+	bool			fib_has_custom_local_routes;
 	struct fib_table __rcu	*fib_main;
 	struct fib_table __rcu	*fib_default;
 #endif
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index d7adc0616599..7ce22a2c07ce 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -137,22 +137,12 @@ static void inet_hash_remove(struct in_ifaddr *ifa)
  */
 struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
 {
-	u32 hash = inet_addr_hash(net, addr);
 	struct net_device *result = NULL;
 	struct in_ifaddr *ifa;
 
 	rcu_read_lock();
-	hlist_for_each_entry_rcu(ifa, &inet_addr_lst[hash], hash) {
-		if (ifa->ifa_local == addr) {
-			struct net_device *dev = ifa->ifa_dev->dev;
-
-			if (!net_eq(dev_net(dev), net))
-				continue;
-			result = dev;
-			break;
-		}
-	}
-	if (!result) {
+	ifa = inet_lookup_ifaddr_rcu(net, addr);
+	if (!ifa) {
 		struct flowi4 fl4 = { .daddr = addr };
 		struct fib_result res = { 0 };
 		struct fib_table *local;
@@ -165,6 +155,8 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
 		    !fib_table_lookup(local, &fl4, &res, FIB_LOOKUP_NOREF) &&
 		    res.type == RTN_LOCAL)
 			result = FIB_RES_DEV(res);
+	} else {
+		result = ifa->ifa_dev->dev;
 	}
 	if (result && devref)
 		dev_hold(result);
@@ -173,6 +165,20 @@ struct net_device *__ip_dev_find(struct net *net, __be32 addr, bool devref)
 }
 EXPORT_SYMBOL(__ip_dev_find);
 
+/* called under RCU lock */
+struct in_ifaddr *inet_lookup_ifaddr_rcu(struct net *net, __be32 addr)
+{
+	u32 hash = inet_addr_hash(net, addr);
+	struct in_ifaddr *ifa;
+
+	hlist_for_each_entry_rcu(ifa, &inet_addr_lst[hash], hash)
+		if (ifa->ifa_local == addr &&
+		    net_eq(dev_net(ifa->ifa_dev->dev), net))
+			return ifa;
+
+	return NULL;
+}
+
 static void rtmsg_ifa(int event, struct in_ifaddr *, struct nlmsghdr *, u32);
 
 static BLOCKING_NOTIFIER_HEAD(inetaddr_chain);
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 37819ab4cc74..f02819134ba2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -345,9 +345,6 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	if (res.type != RTN_UNICAST &&
 	    (res.type != RTN_LOCAL || !IN_DEV_ACCEPT_LOCAL(idev)))
 		goto e_inval;
-	if (!rpf && !fib_num_tclassid_users(net) &&
-	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev)))
-		goto last_resort;
 	fib_combine_itag(itag, &res);
 	dev_match = false;
 
@@ -402,13 +399,26 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 			struct in_device *idev, u32 *itag)
 {
 	int r = secpath_exists(skb) ? 0 : IN_DEV_RPFILTER(idev);
+	struct net *net = dev_net(dev);
 
-	if (!r && !fib_num_tclassid_users(dev_net(dev)) &&
-	    IN_DEV_ACCEPT_LOCAL(idev) &&
+	if (!r && !fib_num_tclassid_users(net) &&
 	    (dev->ifindex != oif || !IN_DEV_TX_REDIRECTS(idev))) {
+		if (IN_DEV_ACCEPT_LOCAL(idev))
+			goto ok;
+		/* if no local routes are added from user space we can check
+		 * for local addresses looking-up the ifaddr table
+		 */
+		if (net->ipv4.fib_has_custom_local_routes)
+			goto full_check;
+		if (inet_lookup_ifaddr_rcu(net, src))
+			return -EINVAL;
+
+ok:
 		*itag = 0;
 		return 0;
 	}
+
+full_check:
 	return __fib_validate_source(skb, src, dst, tos, oif, dev, r, idev, itag);
 }
 
@@ -759,6 +769,8 @@ static int inet_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 	}
 
 	err = fib_table_insert(net, tb, &cfg, extack);
+	if (!err && cfg.fc_type == RTN_LOCAL)
+		net->ipv4.fib_has_custom_local_routes = true;
 errout:
 	return err;
 }