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/*
* iptables module to match inet_addr_type() of an ip.
*
* Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
* (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/ip.h>
#include <net/route.h>
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/ip6_fib.h>
#endif
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/xt_addrtype.h>
#include <linux/netfilter/x_tables.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Xtables: address type match");
MODULE_ALIAS("ipt_addrtype");
MODULE_ALIAS("ip6t_addrtype");
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
static u32 match_lookup_rt6(struct net *net, const struct net_device *dev,
const struct in6_addr *addr, u16 mask)
{
struct flowi6 flow;
struct rt6_info *rt;
u32 ret = 0;
int route_err;
memset(&flow, 0, sizeof(flow));
flow.daddr = *addr;
if (dev)
flow.flowi6_oif = dev->ifindex;
if (dev && (mask & XT_ADDRTYPE_LOCAL)) {
if (nf_ipv6_chk_addr(net, addr, dev, true))
ret = XT_ADDRTYPE_LOCAL;
}
route_err = nf_ip6_route(net, (struct dst_entry **)&rt,
flowi6_to_flowi(&flow), false);
if (route_err)
return XT_ADDRTYPE_UNREACHABLE;
if (rt->rt6i_flags & RTF_REJECT)
ret = XT_ADDRTYPE_UNREACHABLE;
if (dev == NULL && rt->rt6i_flags & RTF_LOCAL)
ret |= XT_ADDRTYPE_LOCAL;
if (ipv6_anycast_destination((struct dst_entry *)rt, addr))
ret |= XT_ADDRTYPE_ANYCAST;
dst_release(&rt->dst);
return ret;
}
static bool match_type6(struct net *net, const struct net_device *dev,
const struct in6_addr *addr, u16 mask)
{
int addr_type = ipv6_addr_type(addr);
if ((mask & XT_ADDRTYPE_MULTICAST) &&
!(addr_type & IPV6_ADDR_MULTICAST))
return false;
if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST))
return false;
if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY)
return false;
if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST |
XT_ADDRTYPE_UNREACHABLE) & mask)
return !!(mask & match_lookup_rt6(net, dev, addr, mask));
return true;
}
static bool
addrtype_mt6(struct net *net, const struct net_device *dev,
const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
bool ret = true;
if (info->source)
ret &= match_type6(net, dev, &iph->saddr, info->source) ^
(info->flags & XT_ADDRTYPE_INVERT_SOURCE);
if (ret && info->dest)
ret &= match_type6(net, dev, &iph->daddr, info->dest) ^
!!(info->flags & XT_ADDRTYPE_INVERT_DEST);
return ret;
}
#endif
static inline bool match_type(struct net *net, const struct net_device *dev,
__be32 addr, u_int16_t mask)
{
return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
}
static bool
addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
{
struct net *net = xt_net(par);
const struct xt_addrtype_info *info = par->matchinfo;
const struct iphdr *iph = ip_hdr(skb);
bool ret = true;
if (info->source)
ret &= match_type(net, NULL, iph->saddr, info->source) ^
info->invert_source;
if (info->dest)
ret &= match_type(net, NULL, iph->daddr, info->dest) ^
info->invert_dest;
return ret;
}
static bool
addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
{
struct net *net = xt_net(par);
const struct xt_addrtype_info_v1 *info = par->matchinfo;
const struct iphdr *iph;
const struct net_device *dev = NULL;
bool ret = true;
if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN)
dev = xt_in(par);
else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)
dev = xt_out(par);
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
if (xt_family(par) == NFPROTO_IPV6)
return addrtype_mt6(net, dev, skb, info);
#endif
iph = ip_hdr(skb);
if (info->source)
ret &= match_type(net, dev, iph->saddr, info->source) ^
(info->flags & XT_ADDRTYPE_INVERT_SOURCE);
if (ret && info->dest)
ret &= match_type(net, dev, iph->daddr, info->dest) ^
!!(info->flags & XT_ADDRTYPE_INVERT_DEST);
return ret;
}
static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
{
const char *errmsg = "both incoming and outgoing interface limitation cannot be selected";
struct xt_addrtype_info_v1 *info = par->matchinfo;
if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN &&
info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)
goto err;
if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
(1 << NF_INET_LOCAL_IN)) &&
info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) {
errmsg = "output interface limitation not valid in PREROUTING and INPUT";
goto err;
}
if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
(1 << NF_INET_LOCAL_OUT)) &&
info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) {
errmsg = "input interface limitation not valid in POSTROUTING and OUTPUT";
goto err;
}
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
if (par->family == NFPROTO_IPV6) {
if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) {
errmsg = "ipv6 BLACKHOLE matching not supported";
goto err;
}
if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) {
errmsg = "ipv6 PROHIBIT (THROW, NAT ..) matching not supported";
goto err;
}
if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) {
errmsg = "ipv6 does not support BROADCAST matching";
goto err;
}
}
#endif
return 0;
err:
pr_info_ratelimited("%s\n", errmsg);
return -EINVAL;
}
static struct xt_match addrtype_mt_reg[] __read_mostly = {
{
.name = "addrtype",
.family = NFPROTO_IPV4,
.match = addrtype_mt_v0,
.matchsize = sizeof(struct xt_addrtype_info),
.me = THIS_MODULE
},
{
.name = "addrtype",
.family = NFPROTO_UNSPEC,
.revision = 1,
.match = addrtype_mt_v1,
.checkentry = addrtype_mt_checkentry_v1,
.matchsize = sizeof(struct xt_addrtype_info_v1),
.me = THIS_MODULE
}
};
static int __init addrtype_mt_init(void)
{
return xt_register_matches(addrtype_mt_reg,
ARRAY_SIZE(addrtype_mt_reg));
}
static void __exit addrtype_mt_exit(void)
{
xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
}
module_init(addrtype_mt_init);
module_exit(addrtype_mt_exit);
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