Artem Savkov <asavkov@xxxxxxxxxx> wrote:
> It is possible for ebt_in_hook to be triggered before ebt_table is assigned
> resulting in a NULL-pointer dereference. Make sure hooks are
> registered as the last step.
Right, thanks for the patch.
> --- a/net/bridge/netfilter/ebtable_broute.c
> +++ b/net/bridge/netfilter/ebtable_broute.c
> @@ -65,7 +65,7 @@ static int ebt_broute(struct sk_buff *skb)
>
> static int __net_init broute_net_init(struct net *net)
> {
> - net->xt.broute_table = ebt_register_table(net, &broute_table, NULL);
> + net->xt.broute_table = ebt_register_table(net, &broute_table);
I wonder if it makes more sense to model this like the iptables version,
i.e. pass net->xt.table_name as last arg to ebt_register_table ...
> +int ebt_register_hooks(struct net *net, struct ebt_table *table,
> + const struct nf_hook_ops *ops)
> +{
> + int ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
> +
> + if (ret)
> + __ebt_unregister_table(net, table);
> +
> + return ret;
> +}
... because this looks strange (unregister of table/not-so-obvious error
unwinding ...)
> @@ -1252,15 +1262,6 @@ ebt_register_table(struct net *net, const struct ebt_table *input_table,
> list_add(&table->list, &net->xt.tables[NFPROTO_BRIDGE]);
> mutex_unlock(&ebt_mutex);
... here one could then assign the net->xt.table_X pointer, and then do
the hook registration right after.
However i have no strong opinion here.
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