xt_addrtype.c 6.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * iptables module to match inet_addr_type() of an ip.
  4. *
  5. * Copyright (c) 2004 Patrick McHardy <kaber@trash.net>
  6. * (C) 2007 Laszlo Attila Toth <panther@balabit.hu>
  7. */
  8. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  9. #include <linux/kernel.h>
  10. #include <linux/module.h>
  11. #include <linux/skbuff.h>
  12. #include <linux/netdevice.h>
  13. #include <linux/ip.h>
  14. #include <net/route.h>
  15. #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  16. #include <net/ipv6.h>
  17. #include <net/ip6_route.h>
  18. #include <net/ip6_fib.h>
  19. #endif
  20. #include <linux/netfilter_ipv6.h>
  21. #include <linux/netfilter/xt_addrtype.h>
  22. #include <linux/netfilter/x_tables.h>
  23. MODULE_LICENSE("GPL");
  24. MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  25. MODULE_DESCRIPTION("Xtables: address type match");
  26. MODULE_ALIAS("ipt_addrtype");
  27. MODULE_ALIAS("ip6t_addrtype");
  28. #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  29. static u32 match_lookup_rt6(struct net *net, const struct net_device *dev,
  30. const struct in6_addr *addr, u16 mask)
  31. {
  32. struct flowi6 flow;
  33. struct rt6_info *rt;
  34. u32 ret = 0;
  35. int route_err;
  36. memset(&flow, 0, sizeof(flow));
  37. flow.daddr = *addr;
  38. if (dev)
  39. flow.flowi6_oif = dev->ifindex;
  40. if (dev && (mask & XT_ADDRTYPE_LOCAL)) {
  41. if (nf_ipv6_chk_addr(net, addr, dev, true))
  42. ret = XT_ADDRTYPE_LOCAL;
  43. }
  44. route_err = nf_ip6_route(net, (struct dst_entry **)&rt,
  45. flowi6_to_flowi(&flow), false);
  46. if (route_err)
  47. return XT_ADDRTYPE_UNREACHABLE;
  48. if (rt->rt6i_flags & RTF_REJECT)
  49. ret = XT_ADDRTYPE_UNREACHABLE;
  50. if (dev == NULL && rt->rt6i_flags & RTF_LOCAL)
  51. ret |= XT_ADDRTYPE_LOCAL;
  52. if (ipv6_anycast_destination((struct dst_entry *)rt, addr))
  53. ret |= XT_ADDRTYPE_ANYCAST;
  54. dst_release(&rt->dst);
  55. return ret;
  56. }
  57. static bool match_type6(struct net *net, const struct net_device *dev,
  58. const struct in6_addr *addr, u16 mask)
  59. {
  60. int addr_type = ipv6_addr_type(addr);
  61. if ((mask & XT_ADDRTYPE_MULTICAST) &&
  62. !(addr_type & IPV6_ADDR_MULTICAST))
  63. return false;
  64. if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST))
  65. return false;
  66. if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY)
  67. return false;
  68. if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST |
  69. XT_ADDRTYPE_UNREACHABLE) & mask)
  70. return !!(mask & match_lookup_rt6(net, dev, addr, mask));
  71. return true;
  72. }
  73. static bool
  74. addrtype_mt6(struct net *net, const struct net_device *dev,
  75. const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info)
  76. {
  77. const struct ipv6hdr *iph = ipv6_hdr(skb);
  78. bool ret = true;
  79. if (info->source)
  80. ret &= match_type6(net, dev, &iph->saddr, info->source) ^
  81. (info->flags & XT_ADDRTYPE_INVERT_SOURCE);
  82. if (ret && info->dest)
  83. ret &= match_type6(net, dev, &iph->daddr, info->dest) ^
  84. !!(info->flags & XT_ADDRTYPE_INVERT_DEST);
  85. return ret;
  86. }
  87. #endif
  88. static inline bool match_type(struct net *net, const struct net_device *dev,
  89. __be32 addr, u_int16_t mask)
  90. {
  91. return !!(mask & (1 << inet_dev_addr_type(net, dev, addr)));
  92. }
  93. static bool
  94. addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
  95. {
  96. struct net *net = xt_net(par);
  97. const struct xt_addrtype_info *info = par->matchinfo;
  98. const struct iphdr *iph = ip_hdr(skb);
  99. bool ret = true;
  100. if (info->source)
  101. ret &= match_type(net, NULL, iph->saddr, info->source) ^
  102. info->invert_source;
  103. if (info->dest)
  104. ret &= match_type(net, NULL, iph->daddr, info->dest) ^
  105. info->invert_dest;
  106. return ret;
  107. }
  108. static bool
  109. addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
  110. {
  111. struct net *net = xt_net(par);
  112. const struct xt_addrtype_info_v1 *info = par->matchinfo;
  113. const struct iphdr *iph;
  114. const struct net_device *dev = NULL;
  115. bool ret = true;
  116. if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN)
  117. dev = xt_in(par);
  118. else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)
  119. dev = xt_out(par);
  120. #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  121. if (xt_family(par) == NFPROTO_IPV6)
  122. return addrtype_mt6(net, dev, skb, info);
  123. #endif
  124. iph = ip_hdr(skb);
  125. if (info->source)
  126. ret &= match_type(net, dev, iph->saddr, info->source) ^
  127. (info->flags & XT_ADDRTYPE_INVERT_SOURCE);
  128. if (ret && info->dest)
  129. ret &= match_type(net, dev, iph->daddr, info->dest) ^
  130. !!(info->flags & XT_ADDRTYPE_INVERT_DEST);
  131. return ret;
  132. }
  133. static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par)
  134. {
  135. const char *errmsg = "both incoming and outgoing interface limitation cannot be selected";
  136. struct xt_addrtype_info_v1 *info = par->matchinfo;
  137. if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN &&
  138. info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT)
  139. goto err;
  140. if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) |
  141. (1 << NF_INET_LOCAL_IN)) &&
  142. info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) {
  143. errmsg = "output interface limitation not valid in PREROUTING and INPUT";
  144. goto err;
  145. }
  146. if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) |
  147. (1 << NF_INET_LOCAL_OUT)) &&
  148. info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) {
  149. errmsg = "input interface limitation not valid in POSTROUTING and OUTPUT";
  150. goto err;
  151. }
  152. #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  153. if (par->family == NFPROTO_IPV6) {
  154. if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) {
  155. errmsg = "ipv6 BLACKHOLE matching not supported";
  156. goto err;
  157. }
  158. if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) {
  159. errmsg = "ipv6 PROHIBIT (THROW, NAT ..) matching not supported";
  160. goto err;
  161. }
  162. if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) {
  163. errmsg = "ipv6 does not support BROADCAST matching";
  164. goto err;
  165. }
  166. }
  167. #endif
  168. return 0;
  169. err:
  170. pr_info_ratelimited("%s\n", errmsg);
  171. return -EINVAL;
  172. }
  173. static struct xt_match addrtype_mt_reg[] __read_mostly = {
  174. {
  175. .name = "addrtype",
  176. .family = NFPROTO_IPV4,
  177. .match = addrtype_mt_v0,
  178. .matchsize = sizeof(struct xt_addrtype_info),
  179. .me = THIS_MODULE
  180. },
  181. {
  182. .name = "addrtype",
  183. .family = NFPROTO_UNSPEC,
  184. .revision = 1,
  185. .match = addrtype_mt_v1,
  186. .checkentry = addrtype_mt_checkentry_v1,
  187. .matchsize = sizeof(struct xt_addrtype_info_v1),
  188. .me = THIS_MODULE
  189. }
  190. };
  191. static int __init addrtype_mt_init(void)
  192. {
  193. return xt_register_matches(addrtype_mt_reg,
  194. ARRAY_SIZE(addrtype_mt_reg));
  195. }
  196. static void __exit addrtype_mt_exit(void)
  197. {
  198. xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
  199. }
  200. module_init(addrtype_mt_init);
  201. module_exit(addrtype_mt_exit);