netfilter: nf_tables: Use stored ifname in netdev hook dumps

The stored ifname and ops.dev->name may deviate after creation due to
interface name changes. Prefer the more deterministic stored name in
dumps which also helps avoiding inadvertent changes to stored ruleset
dumps.

Signed-off-by: Phil Sutter <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>

Author: Phil Sutter

net/netfilter/nf_tables_api.c

@@ -1956,15 +1956,16 @@ static int nft_dump_basechain_hook(struct sk_buff *skb,
 			if (!first)
 				first = hook;
 
-			if (nla_put_string(skb, NFTA_DEVICE_NAME,
-					   hook->ops.dev->name))
+			if (nla_put(skb, NFTA_DEVICE_NAME,
+				    hook->ifnamelen, hook->ifname))
 				goto nla_put_failure;
 			n++;
 		}
 		nla_nest_end(skb, nest_devs);
 
 		if (n == 1 &&
-		    nla_put_string(skb, NFTA_HOOK_DEV, first->ops.dev->name))
+		    nla_put(skb, NFTA_HOOK_DEV,
+			    first->ifnamelen, first->ifname))
 			goto nla_put_failure;
 	}
 	nla_nest_end(skb, nest);
@@ -9324,7 +9325,8 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
 
 	list_for_each_entry_rcu(hook, hook_list, list,
 				lockdep_commit_lock_is_held(net)) {
-		if (nla_put_string(skb, NFTA_DEVICE_NAME, hook->ops.dev->name))
+		if (nla_put(skb, NFTA_DEVICE_NAME,
+			    hook->ifnamelen, hook->ifname))
 			goto nla_put_failure;
 	}
 	nla_nest_end(skb, nest_devs);