1 files changed, 114 insertions, 36 deletions

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index da449ddb8cc1..de9484658232 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -32,6 +32,7 @@
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/slab.h>
+#include <linux/netlink.h>
 
 #include <net/arp.h>
 #include <net/ip.h>
@@ -203,6 +204,7 @@ static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 static void free_fib_info_rcu(struct rcu_head *head)
 {
 	struct fib_info *fi = container_of(head, struct fib_info, rcu);
+	struct dst_metrics *m;
 
 	change_nexthops(fi) {
 		if (nexthop_nh->nh_dev)
@@ -213,8 +215,9 @@ static void free_fib_info_rcu(struct rcu_head *head)
 		rt_fibinfo_free(&nexthop_nh->nh_rth_input);
 	} endfor_nexthops(fi);
 
-	if (fi->fib_metrics != (u32 *) dst_default_metrics)
-		kfree(fi->fib_metrics);
+	m = fi->fib_metrics;
+	if (m != &dst_default_metrics && atomic_dec_and_test(&m->refcnt))
+		kfree(m);
 	kfree(fi);
 }
 
@@ -454,7 +457,8 @@ static int fib_detect_death(struct fib_info *fi, int order,
 
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 
-static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
+static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
+			      struct netlink_ext_ack *extack)
 {
 	int nhs = 0;
 
@@ -464,22 +468,35 @@ static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining)
 	}
 
 	/* leftover implies invalid nexthop configuration, discard it */
-	return remaining > 0 ? 0 : nhs;
+	if (remaining > 0) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid nexthop configuration - extra data after nexthops");
+		nhs = 0;
+	}
+
+	return nhs;
 }
 
 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
-		       int remaining, struct fib_config *cfg)
+		       int remaining, struct fib_config *cfg,
+		       struct netlink_ext_ack *extack)
 {
 	int ret;
 
 	change_nexthops(fi) {
 		int attrlen;
 
-		if (!rtnh_ok(rtnh, remaining))
+		if (!rtnh_ok(rtnh, remaining)) {
+			NL_SET_ERR_MSG(extack,
+				       "Invalid nexthop configuration - extra data after nexthop");
 			return -EINVAL;
+		}
 
-		if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
+		if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
+			NL_SET_ERR_MSG(extack,
+				       "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
 			return -EINVAL;
+		}
 
 		nexthop_nh->nh_flags =
 			(cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
@@ -505,8 +522,12 @@ static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
 
 				nla_entype = nla_find(attrs, attrlen,
 						      RTA_ENCAP_TYPE);
-				if (!nla_entype)
+				if (!nla_entype) {
+					NL_SET_BAD_ATTR(extack, nla);
+					NL_SET_ERR_MSG(extack,
+						       "Encap type is missing");
 					goto err_inval;
+				}
 
 				ret = lwtunnel_build_state(nla_get_u16(
 							   nla_entype),
@@ -714,7 +735,7 @@ int fib_nh_match(struct fib_config *cfg, struct fib_info *fi)
  *					|-> {local prefix} (terminal node)
  */
 static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
-			struct fib_nh *nh)
+			struct fib_nh *nh, struct netlink_ext_ack *extack)
 {
 	int err = 0;
 	struct net *net;
@@ -727,16 +748,25 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
 		if (nh->nh_flags & RTNH_F_ONLINK) {
 			unsigned int addr_type;
 
-			if (cfg->fc_scope >= RT_SCOPE_LINK)
+			if (cfg->fc_scope >= RT_SCOPE_LINK) {
+				NL_SET_ERR_MSG(extack,
+					       "Nexthop has invalid scope");
 				return -EINVAL;
+			}
 			dev = __dev_get_by_index(net, nh->nh_oif);
 			if (!dev)
 				return -ENODEV;
-			if (!(dev->flags & IFF_UP))
+			if (!(dev->flags & IFF_UP)) {
+				NL_SET_ERR_MSG(extack,
+					       "Nexthop device is not up");
 				return -ENETDOWN;
+			}
 			addr_type = inet_addr_type_dev_table(net, dev, nh->nh_gw);
-			if (addr_type != RTN_UNICAST)
+			if (addr_type != RTN_UNICAST) {
+				NL_SET_ERR_MSG(extack,
+					       "Nexthop has invalid gateway");
 				return -EINVAL;
+			}
 			if (!netif_carrier_ok(dev))
 				nh->nh_flags |= RTNH_F_LINKDOWN;
 			nh->nh_dev = dev;
@@ -776,18 +806,25 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
 			}
 
 			if (err) {
+				NL_SET_ERR_MSG(extack,
+					       "Nexthop has invalid gateway");
 				rcu_read_unlock();
 				return err;
 			}
 		}
 		err = -EINVAL;
-		if (res.type != RTN_UNICAST && res.type != RTN_LOCAL)
+		if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
+			NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
 			goto out;
+		}
 		nh->nh_scope = res.scope;
 		nh->nh_oif = FIB_RES_OIF(res);
 		nh->nh_dev = dev = FIB_RES_DEV(res);
-		if (!dev)
+		if (!dev) {
+			NL_SET_ERR_MSG(extack,
+				       "No egress device for nexthop gateway");
 			goto out;
+		}
 		dev_hold(dev);
 		if (!netif_carrier_ok(dev))
 			nh->nh_flags |= RTNH_F_LINKDOWN;
@@ -795,17 +832,21 @@ static int fib_check_nh(struct fib_config *cfg, struct fib_info *fi,
 	} else {
 		struct in_device *in_dev;
 
-		if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK))
+		if (nh->nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
+			NL_SET_ERR_MSG(extack,
+				       "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
 			return -EINVAL;
-
+		}
 		rcu_read_lock();
 		err = -ENODEV;
 		in_dev = inetdev_by_index(net, nh->nh_oif);
 		if (!in_dev)
 			goto out;
 		err = -ENETDOWN;
-		if (!(in_dev->dev->flags & IFF_UP))
+		if (!(in_dev->dev->flags & IFF_UP)) {
+			NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
 			goto out;
+		}
 		nh->nh_dev = in_dev->dev;
 		dev_hold(nh->nh_dev);
 		nh->nh_scope = RT_SCOPE_HOST;
@@ -971,16 +1012,17 @@ fib_convert_metrics(struct fib_info *fi, const struct fib_config *cfg)
 			val = 255;
 		if (type == RTAX_FEATURES && (val & ~RTAX_FEATURE_MASK))
 			return -EINVAL;
-		fi->fib_metrics[type - 1] = val;
+		fi->fib_metrics->metrics[type - 1] = val;
 	}
 
 	if (ecn_ca)
-		fi->fib_metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
+		fi->fib_metrics->metrics[RTAX_FEATURES - 1] |= DST_FEATURE_ECN_CA;
 
 	return 0;
 }
 
-struct fib_info *fib_create_info(struct fib_config *cfg)
+struct fib_info *fib_create_info(struct fib_config *cfg,
+				 struct netlink_ext_ack *extack)
 {
 	int err;
 	struct fib_info *fi = NULL;
@@ -992,15 +1034,20 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 		goto err_inval;
 
 	/* Fast check to catch the most weird cases */
-	if (fib_props[cfg->fc_type].scope > cfg->fc_scope)
+	if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
+		NL_SET_ERR_MSG(extack, "Invalid scope");
 		goto err_inval;
+	}
 
-	if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN))
+	if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
 		goto err_inval;
+	}
 
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	if (cfg->fc_mp) {
-		nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len);
+		nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
 		if (nhs == 0)
 			goto err_inval;
 	}
@@ -1033,11 +1080,12 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 		goto failure;
 	fib_info_cnt++;
 	if (cfg->fc_mx) {
-		fi->fib_metrics = kzalloc(sizeof(u32) * RTAX_MAX, GFP_KERNEL);
+		fi->fib_metrics = kzalloc(sizeof(*fi->fib_metrics), GFP_KERNEL);
 		if (!fi->fib_metrics)
 			goto failure;
+		atomic_set(&fi->fib_metrics->refcnt, 1);
 	} else
-		fi->fib_metrics = (u32 *) dst_default_metrics;
+		fi->fib_metrics = (struct dst_metrics *)&dst_default_metrics;
 
 	fi->fib_net = net;
 	fi->fib_protocol = cfg->fc_protocol;
@@ -1062,18 +1110,29 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 
 	if (cfg->fc_mp) {
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
-		err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg);
+		err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg, extack);
 		if (err != 0)
 			goto failure;
-		if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif)
+		if (cfg->fc_oif && fi->fib_nh->nh_oif != cfg->fc_oif) {
+			NL_SET_ERR_MSG(extack,
+				       "Nexthop device index does not match RTA_OIF");
 			goto err_inval;
-		if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw)
+		}
+		if (cfg->fc_gw && fi->fib_nh->nh_gw != cfg->fc_gw) {
+			NL_SET_ERR_MSG(extack,
+				       "Nexthop gateway does not match RTA_GATEWAY");
 			goto err_inval;
+		}
 #ifdef CONFIG_IP_ROUTE_CLASSID
-		if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow)
+		if (cfg->fc_flow && fi->fib_nh->nh_tclassid != cfg->fc_flow) {
+			NL_SET_ERR_MSG(extack,
+				       "Nexthop class id does not match RTA_FLOW");
 			goto err_inval;
+		}
 #endif
 #else
+		NL_SET_ERR_MSG(extack,
+			       "Multipath support not enabled in kernel");
 		goto err_inval;
 #endif
 	} else {
@@ -1082,8 +1141,11 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 		if (cfg->fc_encap) {
 			struct lwtunnel_state *lwtstate;
 
-			if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE)
+			if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
+				NL_SET_ERR_MSG(extack,
+					       "LWT encap type not specified");
 				goto err_inval;
+			}
 			err = lwtunnel_build_state(cfg->fc_encap_type,
 						   cfg->fc_encap, AF_INET, cfg,
 						   &lwtstate);
@@ -1106,8 +1168,11 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 	}
 
 	if (fib_props[cfg->fc_type].error) {
-		if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp)
+		if (cfg->fc_gw || cfg->fc_oif || cfg->fc_mp) {
+			NL_SET_ERR_MSG(extack,
+				       "Gateway, device and multipath can not be specified for this route type");
 			goto err_inval;
+		}
 		goto link_it;
 	} else {
 		switch (cfg->fc_type) {
@@ -1118,19 +1183,30 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 		case RTN_MULTICAST:
 			break;
 		default:
+			NL_SET_ERR_MSG(extack, "Invalid route type");
 			goto err_inval;
 		}
 	}
 
-	if (cfg->fc_scope > RT_SCOPE_HOST)
+	if (cfg->fc_scope > RT_SCOPE_HOST) {
+		NL_SET_ERR_MSG(extack, "Invalid scope");
 		goto err_inval;
+	}
 
 	if (cfg->fc_scope == RT_SCOPE_HOST) {
 		struct fib_nh *nh = fi->fib_nh;
 
 		/* Local address is added. */
-		if (nhs != 1 || nh->nh_gw)
+		if (nhs != 1) {
+			NL_SET_ERR_MSG(extack,
+				       "Route with host scope can not have multiple nexthops");
+			goto err_inval;
+		}
+		if (nh->nh_gw) {
+			NL_SET_ERR_MSG(extack,
+				       "Route with host scope can not have a gateway");
 			goto err_inval;
+		}
 		nh->nh_scope = RT_SCOPE_NOWHERE;
 		nh->nh_dev = dev_get_by_index(net, fi->fib_nh->nh_oif);
 		err = -ENODEV;
@@ -1140,7 +1216,7 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 		int linkdown = 0;
 
 		change_nexthops(fi) {
-			err = fib_check_nh(cfg, fi, nexthop_nh);
+			err = fib_check_nh(cfg, fi, nexthop_nh, extack);
 			if (err != 0)
 				goto failure;
 			if (nexthop_nh->nh_flags & RTNH_F_LINKDOWN)
@@ -1150,8 +1226,10 @@ struct fib_info *fib_create_info(struct fib_config *cfg)
 			fi->fib_flags |= RTNH_F_LINKDOWN;
 	}
 
-	if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc))
+	if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
+		NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
 		goto err_inval;
+	}
 
 	change_nexthops(fi) {
 		fib_info_update_nh_saddr(net, nexthop_nh);
@@ -1238,7 +1316,7 @@ int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
 	if (fi->fib_priority &&
 	    nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
 		goto nla_put_failure;
-	if (rtnetlink_put_metrics(skb, fi->fib_metrics) < 0)
+	if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
 		goto nla_put_failure;
 
 	if (fi->fib_prefsrc &&