From 835b803377f5f11f9ccf234f70ed667a82605c45 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 15 Jun 2015 12:12:01 +0200 Subject: [PATCH] netfilter: nf_tables_netdev: unregister hooks on net_device removal 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 --- include/net/netfilter/nf_tables.h | 7 +++ net/netfilter/nf_tables_api.c | 16 +++++-- net/netfilter/nf_tables_netdev.c | 75 +++++++++++++++++++++++++++++++ 3 files changed, 94 insertions(+), 4 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 09d6f8df60f0..2a246680a6c3 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -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); diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index c66dc62afb46..cfe636808541 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -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, diff --git a/net/netfilter/nf_tables_netdev.c b/net/netfilter/nf_tables_netdev.c index 04cb17057f46..2cae4d4a03b7 100644 --- a/net/netfilter/nf_tables_netdev.c +++ b/net/netfilter/nf_tables_netdev.c @@ -8,6 +8,7 @@ #include #include +#include #include #include #include @@ -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); } -- 2.20.1