a357b3f80b
MASQUERADE, S/DNAT and REDIRECT already call functions that depend on the conntrack module. However, since the conntrack hooks are now registered in a lazy fashion (i.e., only when needed) a symbol reference is not enough. Thus, when something is added to a nat table, make sure that it will see packets by calling nf_ct_netns_get() which will register the conntrack hooks in the current netns. An alternative would be to add these dependencies to the NAT table. However, that has problems when using non-modular builds -- we might register e.g. ipv6 conntrack before its initcall has run, leading to NULL deref crashes since its per-netns storage has not yet been allocated. Adding the dependency in the modules instead has the advantage that nat table also does not register its hooks until rules are added. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
122 lines
3.3 KiB
C
122 lines
3.3 KiB
C
/*
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* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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* Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Based on Rusty Russell's IPv4 REDIRECT target. Development of IPv6
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* NAT funded by Astaro.
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*/
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#include <linux/if.h>
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#include <linux/inetdevice.h>
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#include <linux/ip.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/netfilter.h>
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#include <linux/types.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_ipv6.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/addrconf.h>
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#include <net/checksum.h>
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#include <net/protocol.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/nf_nat_redirect.h>
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static unsigned int
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redirect_tg6(struct sk_buff *skb, const struct xt_action_param *par)
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{
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return nf_nat_redirect_ipv6(skb, par->targinfo, xt_hooknum(par));
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}
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static int redirect_tg6_checkentry(const struct xt_tgchk_param *par)
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{
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const struct nf_nat_range *range = par->targinfo;
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if (range->flags & NF_NAT_RANGE_MAP_IPS)
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return -EINVAL;
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return nf_ct_netns_get(par->net, par->family);
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}
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static void redirect_tg_destroy(const struct xt_tgdtor_param *par)
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{
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nf_ct_netns_put(par->net, par->family);
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}
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/* FIXME: Take multiple ranges --RR */
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static int redirect_tg4_check(const struct xt_tgchk_param *par)
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{
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const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo;
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if (mr->range[0].flags & NF_NAT_RANGE_MAP_IPS) {
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pr_debug("bad MAP_IPS.\n");
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return -EINVAL;
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}
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if (mr->rangesize != 1) {
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pr_debug("bad rangesize %u.\n", mr->rangesize);
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return -EINVAL;
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}
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return nf_ct_netns_get(par->net, par->family);
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}
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static unsigned int
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redirect_tg4(struct sk_buff *skb, const struct xt_action_param *par)
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{
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return nf_nat_redirect_ipv4(skb, par->targinfo, xt_hooknum(par));
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}
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static struct xt_target redirect_tg_reg[] __read_mostly = {
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{
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.name = "REDIRECT",
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.family = NFPROTO_IPV6,
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.revision = 0,
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.table = "nat",
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.checkentry = redirect_tg6_checkentry,
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.destroy = redirect_tg_destroy,
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.target = redirect_tg6,
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.targetsize = sizeof(struct nf_nat_range),
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.hooks = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_OUT),
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.me = THIS_MODULE,
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},
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{
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.name = "REDIRECT",
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.family = NFPROTO_IPV4,
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.revision = 0,
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.table = "nat",
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.target = redirect_tg4,
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.checkentry = redirect_tg4_check,
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.destroy = redirect_tg_destroy,
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.targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
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.hooks = (1 << NF_INET_PRE_ROUTING) |
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(1 << NF_INET_LOCAL_OUT),
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.me = THIS_MODULE,
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},
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};
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static int __init redirect_tg_init(void)
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{
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return xt_register_targets(redirect_tg_reg,
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ARRAY_SIZE(redirect_tg_reg));
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}
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static void __exit redirect_tg_exit(void)
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{
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xt_unregister_targets(redirect_tg_reg, ARRAY_SIZE(redirect_tg_reg));
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}
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module_init(redirect_tg_init);
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module_exit(redirect_tg_exit);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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MODULE_DESCRIPTION("Xtables: Connection redirection to localhost");
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MODULE_ALIAS("ip6t_REDIRECT");
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MODULE_ALIAS("ipt_REDIRECT");
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