net/netfilter/xt_addrtype.c

   1 /*
   2  *  iptables module to match inet_addr_type() of an ip.
   3  *
   4  *  Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
   5  *  (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  */
  11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/ip.h>
  17 #include <net/route.h>
  18
  19 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  20 #include <net/ipv6.h>
  21 #include <net/ip6_route.h>
  22 #include <net/ip6_fib.h>
  23 #endif
  24
  25 #include <linux/netfilter/xt_addrtype.h>
  26 #include <linux/netfilter/x_tables.h>
  27
  28 MODULE_LICENSE("GPL");
  29 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  30 MODULE_DESCRIPTION("Xtables: address type match");
  31 MODULE_ALIAS("ipt_addrtype");
  32 MODULE_ALIAS("ip6t_addrtype");
  33
  34 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  35 static u32 xt_addrtype_rt6_to_type(const struct rt6_info *rt)
  36 {
  37         u32 ret;
  38
  39         if (!rt)
  40                 return XT_ADDRTYPE_UNREACHABLE;
  41
  42         if (rt->rt6i_flags & RTF_REJECT)
  43                 ret = XT_ADDRTYPE_UNREACHABLE;
  44         else
  45                 ret = 0;
  46
  47         if (rt->rt6i_flags & RTF_LOCAL)
  48                 ret |= XT_ADDRTYPE_LOCAL;
  49         if (rt->rt6i_flags & RTF_ANYCAST)
  50                 ret |= XT_ADDRTYPE_ANYCAST;
  51         return ret;
  52 }
  53
  54 static bool match_type6(struct net *net, const struct net_device *dev,
  55                                 const struct in6_addr *addr, u16 mask)
  56 {
  57         int addr_type = ipv6_addr_type(addr);
  58
  59         if ((mask & XT_ADDRTYPE_MULTICAST) &&
  60             !(addr_type & IPV6_ADDR_MULTICAST))
  61                 return false;
  62         if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST))
  63                 return false;
  64         if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY)
  65                 return false;
  66
  67         if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST |
  68              XT_ADDRTYPE_UNREACHABLE) & mask) {
  69                 struct rt6_info *rt;
  70                 u32 type;
  71                 int ifindex = dev ? dev->ifindex : 0;
  72
  73                 rt = rt6_lookup(net, addr, NULL, ifindex, !!dev);
  74
  75                 type = xt_addrtype_rt6_to_type(rt);
  76
  77                 dst_release(&rt->dst);
  78                 return !!(mask & type);
  79         }
  80         return true;
  81 }
  82
  83 static bool
  84 addrtype_mt6(struct net *net, const struct net_device *dev,
  85         const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info)
  86 {
  87         const struct ipv6hdr *iph = ipv6_hdr(skb);
  88         bool ret = true;
  89
  90         if (info->source)
  91                 ret &= match_type6(net, dev, &iph->saddr, info->source) ^
  92                        (info->flags & XT_ADDRTYPE_INVERT_SOURCE);
  93         if (ret && info->dest)
  94                 ret &= match_type6(net, dev, &iph->daddr, info->dest) ^
  95                        !!(info->flags & XT_ADDRTYPE_INVERT_DEST);
  96         return ret;
  97 }
  98 #endif
  99
 100 static inline bool match_type(struct net *net, const struct net_device *dev,
 101                               __be32 addr, u_int16_t mask)
 102 {
 103         return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
 104 }
 105
 106 static bool
 107 addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
 108 {
 109         struct net *net = dev_net(par->in ? par->in : par->out);
 110         const struct xt_addrtype_info *info = par->matchinfo;
 111         const struct iphdr *iph = ip_hdr(skb);
 112         bool ret = true;
 113
 114         if (info->source)
 115                 ret &= match_type(net, NULL, iph->saddr, info->source) ^
 116                        info->invert_source;
 117         if (info->dest)
 118                 ret &= match_type(net, NULL, iph->daddr, info->dest) ^
 119                        info->invert_dest;
 120
 121         return ret;
 122 }
 123
 124 static bool
 125 addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
 126 {
 127         struct net *net = dev_net(par->in ? par->in : par->out);
 128         const struct xt_addrtype_info_v1 *info = par->matchinfo;
 129         const struct iphdr *iph;
 130         const struct net_device *dev = NULL;
 131         bool ret = true;
 132
 133         if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN)
 134                 dev = par->in;
 135         else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)
 136                 dev = par->out;
 137
 138 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 139         if (par->family == NFPROTO_IPV6)
 140                 return addrtype_mt6(net, dev, skb, info);
 141 #endif
 142         iph = ip_hdr(skb);
 143         if (info->source)
 144                 ret &= match_type(net, dev, iph->saddr, info->source) ^
 145                        (info->flags & XT_ADDRTYPE_INVERT_SOURCE);
 146         if (ret && info->dest)
 147                 ret &= match_type(net, dev, iph->daddr, info->dest) ^
 148                        !!(info->flags & XT_ADDRTYPE_INVERT_DEST);
 149         return ret;
 150 }
 151
 152 static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
 153 {
 154         struct xt_addrtype_info_v1 *info = par->matchinfo;
 155
 156         if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN &&
 157             info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) {
 158                 pr_info("both incoming and outgoing "
 159                         "interface limitation cannot be selected\n");
 160                 return -EINVAL;
 161         }
 162
 163         if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
 164             (1 << NF_INET_LOCAL_IN)) &&
 165             info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) {
 166                 pr_info("output interface limitation "
 167                         "not valid in PREROUTING and INPUT\n");
 168                 return -EINVAL;
 169         }
 170
 171         if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
 172             (1 << NF_INET_LOCAL_OUT)) &&
 173             info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) {
 174                 pr_info("input interface limitation "
 175                         "not valid in POSTROUTING and OUTPUT\n");
 176                 return -EINVAL;
 177         }
 178
 179 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 180         if (par->family == NFPROTO_IPV6) {
 181                 if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) {
 182                         pr_err("ipv6 BLACKHOLE matching not supported\n");
 183                         return -EINVAL;
 184                 }
 185                 if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) {
 186                         pr_err("ipv6 PROHIBT (THROW, NAT ..) matching not supported\n");
 187                         return -EINVAL;
 188                 }
 189                 if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) {
 190                         pr_err("ipv6 does not support BROADCAST matching\n");
 191                         return -EINVAL;
 192                 }
 193         }
 194 #endif
 195         return 0;
 196 }
 197
 198 static struct xt_match addrtype_mt_reg[] __read_mostly = {
 199         {
 200                 .name           = "addrtype",
 201                 .family         = NFPROTO_IPV4,
 202                 .match          = addrtype_mt_v0,
 203                 .matchsize      = sizeof(struct xt_addrtype_info),
 204                 .me             = THIS_MODULE
 205         },
 206         {
 207                 .name           = "addrtype",
 208                 .family         = NFPROTO_UNSPEC,
 209                 .revision       = 1,
 210                 .match          = addrtype_mt_v1,
 211                 .checkentry     = addrtype_mt_checkentry_v1,
 212                 .matchsize      = sizeof(struct xt_addrtype_info_v1),
 213                 .me             = THIS_MODULE
 214         }
 215 };
 216
 217 static int __init addrtype_mt_init(void)
 218 {
 219         return xt_register_matches(addrtype_mt_reg,
 220                                    ARRAY_SIZE(addrtype_mt_reg));
 221 }
 222
 223 static void __exit addrtype_mt_exit(void)
 224 {
 225         xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
 226 }
 227
 228 module_init(addrtype_mt_init);
 229 module_exit(addrtype_mt_exit);