From a4aeafa28cf706f65f763026c26d83e7e8c96592 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 21 Apr 2021 09:51:06 +0200 Subject: netfilter: xt_nat: pass table to hookfn This changes how ip(6)table nat passes the ruleset/table to the evaluation loop. At the moment, it will fetch the table from struct net. This change stores the table in the hook_ops 'priv' argument instead. This requires to duplicate the hook_ops for each netns, so they can store the (per-net) xt_table structure. The dupliated nat hook_ops get stored in net_generic data area. They are free'd in the namespace exit path. This is a pre-requisite to remove the xt_table/ruleset pointers from struct net. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/iptable_nat.c | 44 +++++++++++++++++++++++++++++--------- net/ipv6/netfilter/ip6table_nat.c | 45 ++++++++++++++++++++++++++++++--------- 2 files changed, 69 insertions(+), 20 deletions(-) (limited to 'net') diff --git a/net/ipv4/netfilter/iptable_nat.c b/net/ipv4/netfilter/iptable_nat.c index f4afd28ccc06..dfa9dc63a7b5 100644 --- a/net/ipv4/netfilter/iptable_nat.c +++ b/net/ipv4/netfilter/iptable_nat.c @@ -13,8 +13,14 @@ #include +struct iptable_nat_pernet { + struct nf_hook_ops *nf_nat_ops; +}; + static int __net_init iptable_nat_table_init(struct net *net); +static unsigned int iptable_nat_net_id __read_mostly; + static const struct xt_table nf_nat_ipv4_table = { .name = "nat", .valid_hooks = (1 << NF_INET_PRE_ROUTING) | @@ -30,7 +36,7 @@ static unsigned int iptable_nat_do_chain(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { - return ipt_do_table(skb, state, state->net->ipv4.nat_table); + return ipt_do_table(skb, state, priv); } static const struct nf_hook_ops nf_nat_ipv4_ops[] = { @@ -60,50 +66,67 @@ static const struct nf_hook_ops nf_nat_ipv4_ops[] = { }, }; -static int ipt_nat_register_lookups(struct net *net) +static int ipt_nat_register_lookups(struct net *net, struct xt_table *table) { + struct nf_hook_ops *ops = kmemdup(nf_nat_ipv4_ops, sizeof(nf_nat_ipv4_ops), GFP_KERNEL); + struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id); int i, ret; + if (!ops) + return -ENOMEM; + for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) { - ret = nf_nat_ipv4_register_fn(net, &nf_nat_ipv4_ops[i]); + ops[i].priv = table; + ret = nf_nat_ipv4_register_fn(net, &ops[i]); if (ret) { while (i) - nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[--i]); + nf_nat_ipv4_unregister_fn(net, &ops[--i]); + kfree(ops); return ret; } } + xt_nat_net->nf_nat_ops = ops; return 0; } static void ipt_nat_unregister_lookups(struct net *net) { + struct iptable_nat_pernet *xt_nat_net = net_generic(net, iptable_nat_net_id); + struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops; int i; + if (!ops) + return; + for (i = 0; i < ARRAY_SIZE(nf_nat_ipv4_ops); i++) - nf_nat_ipv4_unregister_fn(net, &nf_nat_ipv4_ops[i]); + nf_nat_ipv4_unregister_fn(net, &ops[i]); + + kfree(ops); } static int __net_init iptable_nat_table_init(struct net *net) { struct ipt_replace *repl; + struct xt_table *table; int ret; repl = ipt_alloc_initial_table(&nf_nat_ipv4_table); if (repl == NULL) return -ENOMEM; ret = ipt_register_table(net, &nf_nat_ipv4_table, repl, - NULL, &net->ipv4.nat_table); + NULL, &table); if (ret < 0) { kfree(repl); return ret; } - ret = ipt_nat_register_lookups(net); + ret = ipt_nat_register_lookups(net, table); if (ret < 0) { ipt_unregister_table_exit(net, "nat"); - net->ipv4.nat_table = NULL; + } else { + net->ipv4.nat_table = table; } kfree(repl); @@ -112,8 +135,7 @@ static int __net_init iptable_nat_table_init(struct net *net) static void __net_exit iptable_nat_net_pre_exit(struct net *net) { - if (net->ipv4.nat_table) - ipt_nat_unregister_lookups(net); + ipt_nat_unregister_lookups(net); } static void __net_exit iptable_nat_net_exit(struct net *net) @@ -125,6 +147,8 @@ static void __net_exit iptable_nat_net_exit(struct net *net) static struct pernet_operations iptable_nat_net_ops = { .pre_exit = iptable_nat_net_pre_exit, .exit = iptable_nat_net_exit, + .id = &iptable_nat_net_id, + .size = sizeof(struct iptable_nat_pernet), }; static int __init iptable_nat_init(void) diff --git a/net/ipv6/netfilter/ip6table_nat.c b/net/ipv6/netfilter/ip6table_nat.c index c7f98755191b..69b7f9601d03 100644 --- a/net/ipv6/netfilter/ip6table_nat.c +++ b/net/ipv6/netfilter/ip6table_nat.c @@ -15,8 +15,14 @@ #include +struct ip6table_nat_pernet { + struct nf_hook_ops *nf_nat_ops; +}; + static int __net_init ip6table_nat_table_init(struct net *net); +static unsigned int ip6table_nat_net_id __read_mostly; + static const struct xt_table nf_nat_ipv6_table = { .name = "nat", .valid_hooks = (1 << NF_INET_PRE_ROUTING) | @@ -32,7 +38,7 @@ static unsigned int ip6table_nat_do_chain(void *priv, struct sk_buff *skb, const struct nf_hook_state *state) { - return ip6t_do_table(skb, state, state->net->ipv6.ip6table_nat); + return ip6t_do_table(skb, state, priv); } static const struct nf_hook_ops nf_nat_ipv6_ops[] = { @@ -62,59 +68,76 @@ static const struct nf_hook_ops nf_nat_ipv6_ops[] = { }, }; -static int ip6t_nat_register_lookups(struct net *net) +static int ip6t_nat_register_lookups(struct net *net, struct xt_table *table) { + struct nf_hook_ops *ops = kmemdup(nf_nat_ipv6_ops, sizeof(nf_nat_ipv6_ops), GFP_KERNEL); + struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id); int i, ret; + if (!ops) + return -ENOMEM; + for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) { - ret = nf_nat_ipv6_register_fn(net, &nf_nat_ipv6_ops[i]); + ops[i].priv = table; + ret = nf_nat_ipv6_register_fn(net, &ops[i]); if (ret) { while (i) - nf_nat_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[--i]); + nf_nat_ipv6_unregister_fn(net, &ops[--i]); + kfree(ops); return ret; } } + xt_nat_net->nf_nat_ops = ops; return 0; } static void ip6t_nat_unregister_lookups(struct net *net) { + struct ip6table_nat_pernet *xt_nat_net = net_generic(net, ip6table_nat_net_id); + struct nf_hook_ops *ops = xt_nat_net->nf_nat_ops; int i; + if (!ops) + return; + for (i = 0; i < ARRAY_SIZE(nf_nat_ipv6_ops); i++) - nf_nat_ipv6_unregister_fn(net, &nf_nat_ipv6_ops[i]); + nf_nat_ipv6_unregister_fn(net, &ops[i]); + + kfree(ops); } static int __net_init ip6table_nat_table_init(struct net *net) { struct ip6t_replace *repl; + struct xt_table *table; int ret; repl = ip6t_alloc_initial_table(&nf_nat_ipv6_table); if (repl == NULL) return -ENOMEM; ret = ip6t_register_table(net, &nf_nat_ipv6_table, repl, - NULL, &net->ipv6.ip6table_nat); + NULL, &table); if (ret < 0) { kfree(repl); return ret; } - ret = ip6t_nat_register_lookups(net); + ret = ip6t_nat_register_lookups(net, table); if (ret < 0) { ip6t_unregister_table_exit(net, "nat"); - net->ipv6.ip6table_nat = NULL; + } else { + net->ipv6.ip6table_nat = table; } + kfree(repl); return ret; } static void __net_exit ip6table_nat_net_pre_exit(struct net *net) { - if (net->ipv6.ip6table_nat) - ip6t_nat_unregister_lookups(net); + ip6t_nat_unregister_lookups(net); } static void __net_exit ip6table_nat_net_exit(struct net *net) @@ -126,6 +149,8 @@ static void __net_exit ip6table_nat_net_exit(struct net *net) static struct pernet_operations ip6table_nat_net_ops = { .pre_exit = ip6table_nat_net_pre_exit, .exit = ip6table_nat_net_exit, + .id = &ip6table_nat_net_id, + .size = sizeof(struct ip6table_nat_pernet), }; static int __init ip6table_nat_init(void) -- cgit v1.2.3