3 files changed, 182 insertions, 105 deletions

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 7b05fd1497ce..b51582d92740 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -684,6 +684,54 @@ errout:
 	return err;
 }
 
+static int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
+		       u8 via_addr[], struct netlink_ext_ack *extack)
+{
+	struct rtvia *via = nla_data(nla);
+	int err = -EINVAL;
+	int alen;
+
+	if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr)) {
+		NL_SET_ERR_MSG_ATTR(extack, nla,
+				    "Invalid attribute length for RTA_VIA");
+		goto errout;
+	}
+	alen = nla_len(nla) -
+			offsetof(struct rtvia, rtvia_addr);
+	if (alen > MAX_VIA_ALEN) {
+		NL_SET_ERR_MSG_ATTR(extack, nla,
+				    "Invalid address length for RTA_VIA");
+		goto errout;
+	}
+
+	/* Validate the address family */
+	switch (via->rtvia_family) {
+	case AF_PACKET:
+		*via_table = NEIGH_LINK_TABLE;
+		break;
+	case AF_INET:
+		*via_table = NEIGH_ARP_TABLE;
+		if (alen != 4)
+			goto errout;
+		break;
+	case AF_INET6:
+		*via_table = NEIGH_ND_TABLE;
+		if (alen != 16)
+			goto errout;
+		break;
+	default:
+		/* Unsupported address family */
+		goto errout;
+	}
+
+	memcpy(via_addr, via->rtvia_addr, alen);
+	*via_alen = alen;
+	err = 0;
+
+errout:
+	return err;
+}
+
 static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
 				  struct mpls_route *rt)
 {
@@ -695,8 +743,6 @@ static int mpls_nh_build_from_cfg(struct mpls_route_config *cfg,
 	if (!nh)
 		return -ENOMEM;
 
-	err = -EINVAL;
-
 	nh->nh_labels = cfg->rc_output_labels;
 	for (i = 0; i < nh->nh_labels; i++)
 		nh->nh_label[i] = cfg->rc_output_label[i];
@@ -720,7 +766,8 @@ errout:
 
 static int mpls_nh_build(struct net *net, struct mpls_route *rt,
 			 struct mpls_nh *nh, int oif, struct nlattr *via,
-			 struct nlattr *newdst, u8 max_labels)
+			 struct nlattr *newdst, u8 max_labels,
+			 struct netlink_ext_ack *extack)
 {
 	int err = -ENOMEM;
 
@@ -728,15 +775,15 @@ static int mpls_nh_build(struct net *net, struct mpls_route *rt,
 		goto errout;
 
 	if (newdst) {
-		err = nla_get_labels(newdst, max_labels,
-				     &nh->nh_labels, nh->nh_label);
+		err = nla_get_labels(newdst, max_labels, &nh->nh_labels,
+				     nh->nh_label, extack);
 		if (err)
 			goto errout;
 	}
 
 	if (via) {
 		err = nla_get_via(via, &nh->nh_via_alen, &nh->nh_via_table,
-				  __mpls_nh_via(rt, nh));
+				  __mpls_nh_via(rt, nh), extack);
 		if (err)
 			goto errout;
 	} else {
@@ -782,7 +829,8 @@ static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
 
 		nla = nla_find(attrs, attrlen, RTA_NEWDST);
 		if (nla &&
-		    nla_get_labels(nla, MAX_NEW_LABELS, &n_labels, NULL) != 0)
+		    nla_get_labels(nla, MAX_NEW_LABELS, &n_labels,
+				   NULL, NULL) != 0)
 			return 0;
 
 		*max_labels = max_t(u8, *max_labels, n_labels);
@@ -802,7 +850,8 @@ static u8 mpls_count_nexthops(struct rtnexthop *rtnh, int len,
 }
 
 static int mpls_nh_build_multi(struct mpls_route_config *cfg,
-			       struct mpls_route *rt, u8 max_labels)
+			       struct mpls_route *rt, u8 max_labels,
+			       struct netlink_ext_ack *extack)
 {
 	struct rtnexthop *rtnh = cfg->rc_mp;
 	struct nlattr *nla_via, *nla_newdst;
@@ -836,7 +885,7 @@ static int mpls_nh_build_multi(struct mpls_route_config *cfg,
 
 		err = mpls_nh_build(cfg->rc_nlinfo.nl_net, rt, nh,
 				    rtnh->rtnh_ifindex, nla_via, nla_newdst,
-				    max_labels);
+				    max_labels, extack);
 		if (err)
 			goto errout;
 
@@ -855,7 +904,28 @@ errout:
 	return err;
 }
 
-static int mpls_route_add(struct mpls_route_config *cfg)
+static bool mpls_label_ok(struct net *net, unsigned int index,
+			  struct netlink_ext_ack *extack)
+{
+	/* Reserved labels may not be set */
+	if (index < MPLS_LABEL_FIRST_UNRESERVED) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid label - must be MPLS_LABEL_FIRST_UNRESERVED or higher");
+		return false;
+	}
+
+	/* The full 20 bit range may not be supported. */
+	if (index >= net->mpls.platform_labels) {
+		NL_SET_ERR_MSG(extack,
+			       "Label >= configured maximum in platform_labels");
+		return false;
+	}
+
+	return true;
+}
+
+static int mpls_route_add(struct mpls_route_config *cfg,
+			  struct netlink_ext_ack *extack)
 {
 	struct mpls_route __rcu **platform_label;
 	struct net *net = cfg->rc_nlinfo.nl_net;
@@ -874,18 +944,15 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 		index = find_free_label(net);
 	}
 
-	/* Reserved labels may not be set */
-	if (index < MPLS_LABEL_FIRST_UNRESERVED)
-		goto errout;
-
-	/* The full 20 bit range may not be supported. */
-	if (index >= net->mpls.platform_labels)
+	if (!mpls_label_ok(net, index, extack))
 		goto errout;
 
 	/* Append makes no sense with mpls */
 	err = -EOPNOTSUPP;
-	if (cfg->rc_nlflags & NLM_F_APPEND)
+	if (cfg->rc_nlflags & NLM_F_APPEND) {
+		NL_SET_ERR_MSG(extack, "MPLS does not support route append");
 		goto errout;
+	}
 
 	err = -EEXIST;
 	platform_label = rtnl_dereference(net->mpls.platform_label);
@@ -912,8 +979,10 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 		nhs = 1;
 	}
 
-	if (nhs == 0)
+	if (nhs == 0) {
+		NL_SET_ERR_MSG(extack, "Route does not contain a nexthop");
 		goto errout;
+	}
 
 	err = -ENOMEM;
 	rt = mpls_rt_alloc(nhs, max_via_alen, max_labels);
@@ -927,7 +996,7 @@ static int mpls_route_add(struct mpls_route_config *cfg)
 	rt->rt_ttl_propagate = cfg->rc_ttl_propagate;
 
 	if (cfg->rc_mp)
-		err = mpls_nh_build_multi(cfg, rt, max_labels);
+		err = mpls_nh_build_multi(cfg, rt, max_labels, extack);
 	else
 		err = mpls_nh_build_from_cfg(cfg, rt);
 	if (err)
@@ -943,7 +1012,8 @@ errout:
 	return err;
 }
 
-static int mpls_route_del(struct mpls_route_config *cfg)
+static int mpls_route_del(struct mpls_route_config *cfg,
+			  struct netlink_ext_ack *extack)
 {
 	struct net *net = cfg->rc_nlinfo.nl_net;
 	unsigned index;
@@ -951,12 +1021,7 @@ static int mpls_route_del(struct mpls_route_config *cfg)
 
 	index = cfg->rc_label;
 
-	/* Reserved labels may not be removed */
-	if (index < MPLS_LABEL_FIRST_UNRESERVED)
-		goto errout;
-
-	/* The full 20 bit range may not be supported */
-	if (index >= net->mpls.platform_labels)
+	if (!mpls_label_ok(net, index, extack))
 		goto errout;
 
 	mpls_route_update(net, index, NULL, &cfg->rc_nlinfo);
@@ -1541,8 +1606,8 @@ int nla_put_labels(struct sk_buff *skb, int attrtype,
 }
 EXPORT_SYMBOL_GPL(nla_put_labels);
 
-int nla_get_labels(const struct nlattr *nla,
-		   u8 max_labels, u8 *labels, u32 label[])
+int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
+		   u32 label[], struct netlink_ext_ack *extack)
 {
 	unsigned len = nla_len(nla);
 	struct mpls_shim_hdr *nla_label;
@@ -1553,13 +1618,18 @@ int nla_get_labels(const struct nlattr *nla,
 	/* len needs to be an even multiple of 4 (the label size). Number
 	 * of labels is a u8 so check for overflow.
 	 */
-	if (len & 3 || len / 4 > 255)
+	if (len & 3 || len / 4 > 255) {
+		NL_SET_ERR_MSG_ATTR(extack, nla,
+				    "Invalid length for labels attribute");
 		return -EINVAL;
+	}
 
 	/* Limit the number of new labels allowed */
 	nla_labels = len/4;
-	if (nla_labels > max_labels)
+	if (nla_labels > max_labels) {
+		NL_SET_ERR_MSG(extack, "Too many labels");
 		return -EINVAL;
+	}
 
 	/* when label == NULL, caller wants number of labels */
 	if (!label)
@@ -1574,8 +1644,29 @@ int nla_get_labels(const struct nlattr *nla,
 		/* Ensure the bottom of stack flag is properly set
 		 * and ttl and tc are both clear.
 		 */
-		if ((dec.bos != bos) || dec.ttl || dec.tc)
+		if (dec.ttl) {
+			NL_SET_ERR_MSG_ATTR(extack, nla,
+					    "TTL in label must be 0");
+			return -EINVAL;
+		}
+
+		if (dec.tc) {
+			NL_SET_ERR_MSG_ATTR(extack, nla,
+					    "Traffic class in label must be 0");
 			return -EINVAL;
+		}
+
+		if (dec.bos != bos) {
+			NL_SET_BAD_ATTR(extack, nla);
+			if (bos) {
+				NL_SET_ERR_MSG(extack,
+					       "BOS bit must be set in first label");
+			} else {
+				NL_SET_ERR_MSG(extack,
+					       "BOS bit can only be set in first label");
+			}
+			return -EINVAL;
+		}
 
 		switch (dec.label) {
 		case MPLS_LABEL_IMPLNULL:
@@ -1583,6 +1674,8 @@ int nla_get_labels(const struct nlattr *nla,
 			 * assign and distribute, but which never
 			 * actually appears in the encapsulation.
 			 */
+			NL_SET_ERR_MSG_ATTR(extack, nla,
+					    "Implicit NULL Label (3) can not be used in encapsulation");
 			return -EINVAL;
 		}
 
@@ -1594,50 +1687,10 @@ out:
 }
 EXPORT_SYMBOL_GPL(nla_get_labels);
 
-int nla_get_via(const struct nlattr *nla, u8 *via_alen,
-		u8 *via_table, u8 via_addr[])
-{
-	struct rtvia *via = nla_data(nla);
-	int err = -EINVAL;
-	int alen;
-
-	if (nla_len(nla) < offsetof(struct rtvia, rtvia_addr))
-		goto errout;
-	alen = nla_len(nla) -
-			offsetof(struct rtvia, rtvia_addr);
-	if (alen > MAX_VIA_ALEN)
-		goto errout;
-
-	/* Validate the address family */
-	switch (via->rtvia_family) {
-	case AF_PACKET:
-		*via_table = NEIGH_LINK_TABLE;
-		break;
-	case AF_INET:
-		*via_table = NEIGH_ARP_TABLE;
-		if (alen != 4)
-			goto errout;
-		break;
-	case AF_INET6:
-		*via_table = NEIGH_ND_TABLE;
-		if (alen != 16)
-			goto errout;
-		break;
-	default:
-		/* Unsupported address family */
-		goto errout;
-	}
-
-	memcpy(via_addr, via->rtvia_addr, alen);
-	*via_alen = alen;
-	err = 0;
-
-errout:
-	return err;
-}
-
-static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
-			       struct mpls_route_config *cfg)
+static int rtm_to_route_config(struct sk_buff *skb,
+			       struct nlmsghdr *nlh,
+			       struct mpls_route_config *cfg,
+			       struct netlink_ext_ack *extack)
 {
 	struct rtmsg *rtm;
 	struct nlattr *tb[RTA_MAX+1];
@@ -1645,35 +1698,54 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 	int err;
 
 	err = nlmsg_parse(nlh, sizeof(*rtm), tb, RTA_MAX, rtm_mpls_policy,
-			  NULL);
+			  extack);
 	if (err < 0)
 		goto errout;
 
 	err = -EINVAL;
 	rtm = nlmsg_data(nlh);
 
-	if (rtm->rtm_family != AF_MPLS)
+	if (rtm->rtm_family != AF_MPLS) {
+		NL_SET_ERR_MSG(extack, "Invalid address family in rtmsg");
 		goto errout;
-	if (rtm->rtm_dst_len != 20)
+	}
+	if (rtm->rtm_dst_len != 20) {
+		NL_SET_ERR_MSG(extack, "rtm_dst_len must be 20 for MPLS");
 		goto errout;
-	if (rtm->rtm_src_len != 0)
+	}
+	if (rtm->rtm_src_len != 0) {
+		NL_SET_ERR_MSG(extack, "rtm_src_len must be 0 for MPLS");
 		goto errout;
-	if (rtm->rtm_tos != 0)
+	}
+	if (rtm->rtm_tos != 0) {
+		NL_SET_ERR_MSG(extack, "rtm_tos must be 0 for MPLS");
 		goto errout;
-	if (rtm->rtm_table != RT_TABLE_MAIN)
+	}
+	if (rtm->rtm_table != RT_TABLE_MAIN) {
+		NL_SET_ERR_MSG(extack,
+			       "MPLS only supports the main route table");
 		goto errout;
+	}
 	/* Any value is acceptable for rtm_protocol */
 
 	/* As mpls uses destination specific addresses
 	 * (or source specific address in the case of multicast)
 	 * all addresses have universal scope.
 	 */
-	if (rtm->rtm_scope != RT_SCOPE_UNIVERSE)
+	if (rtm->rtm_scope != RT_SCOPE_UNIVERSE) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid route scope  - MPLS only supports UNIVERSE");
 		goto errout;
-	if (rtm->rtm_type != RTN_UNICAST)
+	}
+	if (rtm->rtm_type != RTN_UNICAST) {
+		NL_SET_ERR_MSG(extack,
+			       "Invalid route type - MPLS only supports UNICAST");
 		goto errout;
-	if (rtm->rtm_flags != 0)
+	}
+	if (rtm->rtm_flags != 0) {
+		NL_SET_ERR_MSG(extack, "rtm_flags must be 0 for MPLS");
 		goto errout;
+	}
 
 	cfg->rc_label		= LABEL_NOT_SPECIFIED;
 	cfg->rc_protocol	= rtm->rtm_protocol;
@@ -1696,26 +1768,26 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 		case RTA_NEWDST:
 			if (nla_get_labels(nla, MAX_NEW_LABELS,
 					   &cfg->rc_output_labels,
-					   cfg->rc_output_label))
+					   cfg->rc_output_label, extack))
 				goto errout;
 			break;
 		case RTA_DST:
 		{
 			u8 label_count;
 			if (nla_get_labels(nla, 1, &label_count,
-					   &cfg->rc_label))
+					   &cfg->rc_label, extack))
 				goto errout;
 
-			/* Reserved labels may not be set */
-			if (cfg->rc_label < MPLS_LABEL_FIRST_UNRESERVED)
+			if (!mpls_label_ok(cfg->rc_nlinfo.nl_net,
+					   cfg->rc_label, extack))
 				goto errout;
-
 			break;
 		}
 		case RTA_VIA:
 		{
 			if (nla_get_via(nla, &cfg->rc_via_alen,
-					&cfg->rc_via_table, cfg->rc_via))
+					&cfg->rc_via_table, cfg->rc_via,
+					extack))
 				goto errout;
 			break;
 		}
@@ -1729,14 +1801,18 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 		{
 			u8 ttl_propagate = nla_get_u8(nla);
 
-			if (ttl_propagate > 1)
+			if (ttl_propagate > 1) {
+				NL_SET_ERR_MSG_ATTR(extack, nla,
+						    "RTA_TTL_PROPAGATE can only be 0 or 1");
 				goto errout;
+			}
 			cfg->rc_ttl_propagate = ttl_propagate ?
 				MPLS_TTL_PROP_ENABLED :
 				MPLS_TTL_PROP_DISABLED;
 			break;
 		}
 		default:
+			NL_SET_ERR_MSG_ATTR(extack, nla, "Unknown attribute");
 			/* Unsupported attribute */
 			goto errout;
 		}
@@ -1757,11 +1833,11 @@ static int mpls_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (!cfg)
 		return -ENOMEM;
 
-	err = rtm_to_route_config(skb, nlh, cfg);
+	err = rtm_to_route_config(skb, nlh, cfg, extack);
 	if (err < 0)
 		goto out;
 
-	err = mpls_route_del(cfg);
+	err = mpls_route_del(cfg, extack);
 out:
 	kfree(cfg);
 
@@ -1779,11 +1855,11 @@ static int mpls_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (!cfg)
 		return -ENOMEM;
 
-	err = rtm_to_route_config(skb, nlh, cfg);
+	err = rtm_to_route_config(skb, nlh, cfg, extack);
 	if (err < 0)
 		goto out;
 
-	err = mpls_route_add(cfg);
+	err = mpls_route_add(cfg, extack);
 out:
 	kfree(cfg);
 
diff --git a/net/mpls/internal.h b/net/mpls/internal.h
index 4db6a5971322..cf65aec2e551 100644
--- a/net/mpls/internal.h
+++ b/net/mpls/internal.h
@@ -203,9 +203,7 @@ static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)
 int nla_put_labels(struct sk_buff *skb, int attrtype,  u8 labels,
 		   const u32 label[]);
 int nla_get_labels(const struct nlattr *nla, u8 max_labels, u8 *labels,
-		   u32 label[]);
-int nla_get_via(const struct nlattr *nla, u8 *via_alen, u8 *via_table,
-		u8 via[]);
+		   u32 label[], struct netlink_ext_ack *extack);
 bool mpls_output_possible(const struct net_device *dev);
 unsigned int mpls_dev_mtu(const struct net_device *dev);
 bool mpls_pkt_too_big(const struct sk_buff *skb, unsigned int mtu);
diff --git a/net/mpls/mpls_iptunnel.c b/net/mpls/mpls_iptunnel.c
index 369c7a23c86c..6e558a419f60 100644
--- a/net/mpls/mpls_iptunnel.c
+++ b/net/mpls/mpls_iptunnel.c
@@ -159,7 +159,8 @@ drop:
 
 static int mpls_build_state(struct nlattr *nla,
 			    unsigned int family, const void *cfg,
-			    struct lwtunnel_state **ts)
+			    struct lwtunnel_state **ts,
+			    struct netlink_ext_ack *extack)
 {
 	struct mpls_iptunnel_encap *tun_encap_info;
 	struct nlattr *tb[MPLS_IPTUNNEL_MAX + 1];
@@ -168,17 +169,18 @@ static int mpls_build_state(struct nlattr *nla,
 	int ret;
 
 	ret = nla_parse_nested(tb, MPLS_IPTUNNEL_MAX, nla,
-			       mpls_iptunnel_policy, NULL);
+			       mpls_iptunnel_policy, extack);
 	if (ret < 0)
 		return ret;
 
-	if (!tb[MPLS_IPTUNNEL_DST])
+	if (!tb[MPLS_IPTUNNEL_DST]) {
+		NL_SET_ERR_MSG(extack, "MPLS_IPTUNNEL_DST attribute is missing");
 		return -EINVAL;
-
+	}
 
 	/* determine number of labels */
-	if (nla_get_labels(tb[MPLS_IPTUNNEL_DST],
-			   MAX_NEW_LABELS, &n_labels, NULL))
+	if (nla_get_labels(tb[MPLS_IPTUNNEL_DST], MAX_NEW_LABELS,
+			   &n_labels, NULL, extack))
 		return -EINVAL;
 
 	newts = lwtunnel_state_alloc(sizeof(*tun_encap_info) +
@@ -188,7 +190,8 @@ static int mpls_build_state(struct nlattr *nla,
 
 	tun_encap_info = mpls_lwtunnel_encap(newts);
 	ret = nla_get_labels(tb[MPLS_IPTUNNEL_DST], n_labels,
-			     &tun_encap_info->labels, tun_encap_info->label);
+			     &tun_encap_info->labels, tun_encap_info->label,
+			     extack);
 	if (ret)
 		goto errout;