netfilter: nf_tables: use dev->name directly

no need to store the name in separate area.

Furthermore, it uses kmalloc but not kfree and most accesses seem to treat
it as char[IFNAMSIZ] not char *.

Remove this and use dev->name instead.

In case event zeroed dev, just omit the name in the dump.

Fixes: d92191aa84e5f1 ("netfilter: nf_tables: cache device name in flowtable object")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 4e82a4c..dc417ef 100644 (file)
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -1124,7 +1124,6 @@ struct nft_flowtable {
        u32                             genmask:2,
                                        use:30;
        u64                             handle;
-       char                            *dev_name[NFT_FLOWTABLE_DEVICE_MAX];
        /* runtime data below here */
        struct nf_hook_ops              *ops ____cacheline_aligned;
        struct nf_flowtable             data;

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index d41fa2c..54a4f75 100644 (file)
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -5324,8 +5324,6 @@ static int nf_tables_flowtable_parse_hook(const struct nft_ctx *ctx,
                flowtable->ops[i].priv          = &flowtable->data;
                flowtable->ops[i].hook          = flowtable->data.type->hook;
                flowtable->ops[i].dev           = dev_array[i];
-               flowtable->dev_name[i]          = kstrdup(dev_array[i]->name,
-                                                         GFP_KERNEL);
        }
 
        return err;
@@ -5483,10 +5481,8 @@ static int nf_tables_newflowtable(struct net *net, struct sock *nlsk,
 err6:
        i = flowtable->ops_len;
 err5:
-       for (k = i - 1; k >= 0; k--) {
-               kfree(flowtable->dev_name[k]);
+       for (k = i - 1; k >= 0; k--)
                nf_unregister_net_hook(net, &flowtable->ops[k]);
-       }
 
        kfree(flowtable->ops);
 err4:
@@ -5585,9 +5581,10 @@ static int nf_tables_fill_flowtable_info(struct sk_buff *skb, struct net *net,
                goto nla_put_failure;
 
        for (i = 0; i < flowtable->ops_len; i++) {
-               if (flowtable->dev_name[i][0] &&
-                   nla_put_string(skb, NFTA_DEVICE_NAME,
-                                  flowtable->dev_name[i]))
+               const struct net_device *dev = READ_ONCE(flowtable->ops[i].dev);
+
+               if (dev &&
+                   nla_put_string(skb, NFTA_DEVICE_NAME, dev->name))
                        goto nla_put_failure;
        }
        nla_nest_end(skb, nest_devs);
@@ -5829,7 +5826,6 @@ static void nft_flowtable_event(unsigned long event, struct net_device *dev,
                        continue;
 
                nf_unregister_net_hook(dev_net(dev), &flowtable->ops[i]);
-               flowtable->dev_name[i][0] = '\0';
                flowtable->ops[i].dev = NULL;
                break;
        }