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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>
98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/* Masquerade. Simple mapping which alters range to a local IP address
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(depending on route). */
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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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*
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/types.h>
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#include <linux/inetdevice.h>
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#include <linux/ip.h>
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#include <linux/timer.h>
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#include <linux/module.h>
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#include <linux/netfilter.h>
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#include <net/protocol.h>
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#include <net/ip.h>
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#include <net/checksum.h>
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#include <net/route.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter/x_tables.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/ipv4/nf_nat_masquerade.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
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MODULE_DESCRIPTION("Xtables: automatic-address SNAT");
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/* FIXME: Multiple targets. --RR */
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static int masquerade_tg_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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masquerade_tg(struct sk_buff *skb, const struct xt_action_param *par)
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{
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struct nf_nat_range range;
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const struct nf_nat_ipv4_multi_range_compat *mr;
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mr = par->targinfo;
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range.flags = mr->range[0].flags;
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range.min_proto = mr->range[0].min;
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range.max_proto = mr->range[0].max;
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return nf_nat_masquerade_ipv4(skb, xt_hooknum(par), &range,
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xt_out(par));
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}
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static void masquerade_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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static struct xt_target masquerade_tg_reg __read_mostly = {
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.name = "MASQUERADE",
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.family = NFPROTO_IPV4,
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.target = masquerade_tg,
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.targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat),
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.table = "nat",
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.hooks = 1 << NF_INET_POST_ROUTING,
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.checkentry = masquerade_tg_check,
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.destroy = masquerade_tg_destroy,
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.me = THIS_MODULE,
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};
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static int __init masquerade_tg_init(void)
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{
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int ret;
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ret = xt_register_target(&masquerade_tg_reg);
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if (ret == 0)
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nf_nat_masquerade_ipv4_register_notifier();
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return ret;
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}
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static void __exit masquerade_tg_exit(void)
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{
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xt_unregister_target(&masquerade_tg_reg);
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nf_nat_masquerade_ipv4_unregister_notifier();
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}
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module_init(masquerade_tg_init);
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module_exit(masquerade_tg_exit);
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