netfilter: nf_tables: free flowtable hooks on hook register error

If hook registration fails, the hooks allocated via nft_netdev_hook_alloc
need to be freed.

We can't change the goto label to 'goto 5' -- while it does fix the memleak
it does cause a warning splat from the netfilter core (the hooks were not
registered).

Fixes: 3f0465a9ef02 ("netfilter: nf_tables: dynamically allocate hooks per net_device in flowtables")
Reported-by: syzbot+a2ff6fa45162a5ed4dd3@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d1318bd..bb064aa 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -6300,8 +6300,13 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
                goto err4;
 
        err = nft_register_flowtable_net_hooks(ctx.net, table, flowtable);
-       if (err < 0)
+       if (err < 0) {
+               list_for_each_entry_safe(hook, next, &flowtable->hook_list, list) {
+                       list_del_rcu(&hook->list);
+                       kfree_rcu(hook, rcu);
+               }
                goto err4;
+       }
 
        err = nft_trans_flowtable_add(&ctx, NFT_MSG_NEWFLOWTABLE, flowtable);
        if (err < 0)