Merge branch 'rtnetlink-a-couple-of-fixes-in-linkmsg-validation'

Xin Long says:

====================
rtnetlink: a couple of fixes in linkmsg validation

validate_linkmsg() was introduced to do linkmsg validation for existing
links. However, the new created links also need this linkmsg validation.

Add validate_linkmsg() check for link creating in Patch 1, and add more
tb checks into validate_linkmsg() in Patch 2 and 3.
====================

Link: https://lore.kernel.org/r/cover.1685548598.git.lucien.xin@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/rtnetlink.c

@@ -2385,6 +2385,37 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[],
 		if (tb[IFLA_BROADCAST] &&
 		    nla_len(tb[IFLA_BROADCAST]) < dev->addr_len)
 			return -EINVAL;
+
+		if (tb[IFLA_GSO_MAX_SIZE] &&
+		    nla_get_u32(tb[IFLA_GSO_MAX_SIZE]) > dev->tso_max_size) {
+			NL_SET_ERR_MSG(extack, "too big gso_max_size");
+			return -EINVAL;
+		}
+
+		if (tb[IFLA_GSO_MAX_SEGS] &&
+		    (nla_get_u32(tb[IFLA_GSO_MAX_SEGS]) > GSO_MAX_SEGS ||
+		     nla_get_u32(tb[IFLA_GSO_MAX_SEGS]) > dev->tso_max_segs)) {
+			NL_SET_ERR_MSG(extack, "too big gso_max_segs");
+			return -EINVAL;
+		}
+
+		if (tb[IFLA_GRO_MAX_SIZE] &&
+		    nla_get_u32(tb[IFLA_GRO_MAX_SIZE]) > GRO_MAX_SIZE) {
+			NL_SET_ERR_MSG(extack, "too big gro_max_size");
+			return -EINVAL;
+		}
+
+		if (tb[IFLA_GSO_IPV4_MAX_SIZE] &&
+		    nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]) > dev->tso_max_size) {
+			NL_SET_ERR_MSG(extack, "too big gso_ipv4_max_size");
+			return -EINVAL;
+		}
+
+		if (tb[IFLA_GRO_IPV4_MAX_SIZE] &&
+		    nla_get_u32(tb[IFLA_GRO_IPV4_MAX_SIZE]) > GRO_MAX_SIZE) {
+			NL_SET_ERR_MSG(extack, "too big gro_ipv4_max_size");
+			return -EINVAL;
+		}
 	}
 
 	if (tb[IFLA_AF_SPEC]) {
@@ -2858,11 +2889,6 @@ static int do_setlink(const struct sk_buff *skb,
 	if (tb[IFLA_GSO_MAX_SIZE]) {
 		u32 max_size = nla_get_u32(tb[IFLA_GSO_MAX_SIZE]);
 
-		if (max_size > dev->tso_max_size) {
-			err = -EINVAL;
-			goto errout;
-		}
-
 		if (dev->gso_max_size ^ max_size) {
 			netif_set_gso_max_size(dev, max_size);
 			status |= DO_SETLINK_MODIFIED;
@@ -2872,11 +2898,6 @@ static int do_setlink(const struct sk_buff *skb,
 	if (tb[IFLA_GSO_MAX_SEGS]) {
 		u32 max_segs = nla_get_u32(tb[IFLA_GSO_MAX_SEGS]);
 
-		if (max_segs > GSO_MAX_SEGS || max_segs > dev->tso_max_segs) {
-			err = -EINVAL;
-			goto errout;
-		}
-
 		if (dev->gso_max_segs ^ max_segs) {
 			netif_set_gso_max_segs(dev, max_segs);
 			status |= DO_SETLINK_MODIFIED;
@@ -2895,11 +2916,6 @@ static int do_setlink(const struct sk_buff *skb,
 	if (tb[IFLA_GSO_IPV4_MAX_SIZE]) {
 		u32 max_size = nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]);
 
-		if (max_size > dev->tso_max_size) {
-			err = -EINVAL;
-			goto errout;
-		}
-
 		if (dev->gso_ipv4_max_size ^ max_size) {
 			netif_set_gso_ipv4_max_size(dev, max_size);
 			status |= DO_SETLINK_MODIFIED;
@@ -3285,6 +3301,7 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname,
 	struct net_device *dev;
 	unsigned int num_tx_queues = 1;
 	unsigned int num_rx_queues = 1;
+	int err;
 
 	if (tb[IFLA_NUM_TX_QUEUES])
 		num_tx_queues = nla_get_u32(tb[IFLA_NUM_TX_QUEUES]);
@@ -3320,13 +3337,18 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname,
 	if (!dev)
 		return ERR_PTR(-ENOMEM);
 
+	err = validate_linkmsg(dev, tb, extack);
+	if (err < 0) {
+		free_netdev(dev);
+		return ERR_PTR(err);
+	}
+
 	dev_net_set(dev, net);
 	dev->rtnl_link_ops = ops;
 	dev->rtnl_link_state = RTNL_LINK_INITIALIZING;
 
 	if (tb[IFLA_MTU]) {
 		u32 mtu = nla_get_u32(tb[IFLA_MTU]);
-		int err;
 
 		err = dev_validate_mtu(dev, mtu, extack);
 		if (err) {