[PATCH nf-next 3/4] netfilter: nf_tables: allow only one netdev per flowtable

[Pablo Neira Ayuso]

Allow netdevice only once per flowtable, otherwise hit EEXIST.

Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
---
 net/netfilter/nf_tables_api.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 0e0e35876b53..80ded807d529 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1538,6 +1538,19 @@ static struct nft_hook *nft_netdev_hook_alloc(struct net 
*net,
        return ERR_PTR(err);
 }
 
+static bool nft_hook_list_find(struct list_head *hook_list,
+                              const struct nft_hook *this)
+{
+       struct nft_hook *hook;
+
+       list_for_each_entry(hook, hook_list, list) {
+               if (this->ops.dev == hook->ops.dev)
+                       return true;
+       }
+
+       return false;
+}
+
 static int nf_tables_parse_netdev_hooks(struct net *net,
                                        const struct nlattr *attr,
                                        struct list_head *hook_list)
@@ -1557,6 +1570,10 @@ static int nf_tables_parse_netdev_hooks(struct net *net,
                        err = PTR_ERR(hook);
                        goto err_hook;
                }
+               if (nft_hook_list_find(hook_list, hook)) {
+                       err = -EEXIST;
+                       goto err_hook;
+               }
                list_add_tail(&hook->list, hook_list);
                n++;
 
-- 
2.11.0