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netfilter: nf_tables_netdev: unregister hooks on net_device removal

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In case the net_device is gone, we have to unregister the hooks and put back
the reference on the net_device object. Once it comes back, register them
again. This also covers the device rename case.

This patch also adds a new flag to indicate that the basechain is disabled, so
their hooks are not registered. This flag is used by the netdev family to
handle the case where the net_device object is gone. Currently this flag is not
exposed to userspace.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2015-06-15 12:12:01 +02:00
parent d8ee8f7c56
commit 835b803377
3 changed files with 94 additions and 4 deletions
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7
include/net/netfilter/nf_tables.h
View File

@ -781,6 +781,7 @@ struct nft_stats {
};
#define NFT_HOOK_OPS_MAX 2
#define NFT_BASECHAIN_DISABLED (1 << 0)
/**
* struct nft_base_chain - nf_tables base chain
@ -798,6 +799,7 @@ struct nft_base_chain {
possible_net_t pnet;
const struct nf_chain_type *type;
u8 policy;
u8 flags;
struct nft_stats __percpu *stats;
struct nft_chain chain;
char dev_name[IFNAMSIZ];
@ -808,6 +810,11 @@ static inline struct nft_base_chain *nft_base_chain(const struct nft_chain *chai
return container_of(chain, struct nft_base_chain, chain);
}
int nft_register_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops);
void nft_unregister_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops);
unsigned int nft_do_chain(struct nft_pktinfo *pkt,
const struct nf_hook_ops *ops);

16
net/netfilter/nf_tables_api.c
View File

@ -127,17 +127,25 @@ static void nft_trans_destroy(struct nft_trans *trans)
kfree(trans);
}
static int nft_register_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops)
int nft_register_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops)
{
if (basechain->flags & NFT_BASECHAIN_DISABLED)
return 0;
return nf_register_hooks(basechain->ops, hook_nops);
}
EXPORT_SYMBOL_GPL(nft_register_basechain);
static void nft_unregister_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops)
void nft_unregister_basechain(struct nft_base_chain *basechain,
unsigned int hook_nops)
{
if (basechain->flags & NFT_BASECHAIN_DISABLED)
return;
nf_unregister_hooks(basechain->ops, hook_nops);
}
EXPORT_SYMBOL_GPL(nft_unregister_basechain);
static int nf_tables_register_hooks(const struct nft_table *table,
struct nft_chain *chain,

75
net/netfilter/nf_tables_netdev.c
View File

@ -8,6 +8,7 @@
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <net/netfilter/nf_tables.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
@ -157,6 +158,77 @@ static const struct nf_chain_type nft_filter_chain_netdev = {
.hook_mask = (1 << NF_NETDEV_INGRESS),
};
static void nft_netdev_event(unsigned long event, struct nft_af_info *afi,
struct net_device *dev, struct nft_table *table,
struct nft_base_chain *basechain)
{
switch (event) {
case NETDEV_REGISTER:
if (strcmp(basechain->dev_name, dev->name) != 0)
return;
BUG_ON(!(basechain->flags & NFT_BASECHAIN_DISABLED));
dev_hold(dev);
basechain->ops[0].dev = dev;
basechain->flags &= ~NFT_BASECHAIN_DISABLED;
if (!(table->flags & NFT_TABLE_F_DORMANT))
nft_register_basechain(basechain, afi->nops);
break;
case NETDEV_UNREGISTER:
if (strcmp(basechain->dev_name, dev->name) != 0)
return;
BUG_ON(basechain->flags & NFT_BASECHAIN_DISABLED);
if (!(table->flags & NFT_TABLE_F_DORMANT))
nft_unregister_basechain(basechain, afi->nops);
dev_put(basechain->ops[0].dev);
basechain->ops[0].dev = NULL;
basechain->flags |= NFT_BASECHAIN_DISABLED;
break;
case NETDEV_CHANGENAME:
if (dev->ifindex != basechain->ops[0].dev->ifindex)
return;
strncpy(basechain->dev_name, dev->name, IFNAMSIZ);
break;
}
}
static int nf_tables_netdev_event(struct notifier_block *this,
unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct nft_af_info *afi;
struct nft_table *table;
struct nft_chain *chain;
nfnl_lock(NFNL_SUBSYS_NFTABLES);
list_for_each_entry(afi, &dev_net(dev)->nft.af_info, list) {
if (afi->family != NFPROTO_NETDEV)
continue;
list_for_each_entry(table, &afi->tables, list) {
list_for_each_entry(chain, &table->chains, list) {
if (!(chain->flags & NFT_BASE_CHAIN))
continue;
nft_netdev_event(event, afi, dev, table,
nft_base_chain(chain));
}
}
}
nfnl_unlock(NFNL_SUBSYS_NFTABLES);
return NOTIFY_DONE;
}
static struct notifier_block nf_tables_netdev_notifier = {
.notifier_call = nf_tables_netdev_event,
};
static int __init nf_tables_netdev_init(void)
{
int ret;
@ -166,11 +238,14 @@ static int __init nf_tables_netdev_init(void)
if (ret < 0)
nft_unregister_chain_type(&nft_filter_chain_netdev);
register_netdevice_notifier(&nf_tables_netdev_notifier);
return ret;
}
static void __exit nf_tables_netdev_exit(void)
{
unregister_netdevice_notifier(&nf_tables_netdev_notifier);
unregister_pernet_subsys(&nf_tables_netdev_net_ops);
nft_unregister_chain_type(&nft_filter_chain_netdev);
}