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 IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 20 #include <net/ipv6.h> 21 #include <net/ip6_route.h> 22 #include <net/ip6_fib.h> 23 #endif 24 25 #include <linux/netfilter_ipv6.h> 26 #include <linux/netfilter/xt_addrtype.h> 27 #include <linux/netfilter/x_tables.h> 28 29 MODULE_LICENSE("GPL"); 30 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); 31 MODULE_DESCRIPTION("Xtables: address type match"); 32 MODULE_ALIAS("ipt_addrtype"); 33 MODULE_ALIAS("ip6t_addrtype"); 34 35 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 36 static u32 match_lookup_rt6(struct net *net, const struct net_device *dev, 37 const struct in6_addr *addr, u16 mask) 38 { 39 const struct nf_ipv6_ops *v6ops; 40 struct flowi6 flow; 41 struct rt6_info *rt; 42 u32 ret = 0; 43 int route_err; 44 45 memset(&flow, 0, sizeof(flow)); 46 flow.daddr = *addr; 47 if (dev) 48 flow.flowi6_oif = dev->ifindex; 49 50 v6ops = nf_get_ipv6_ops(); 51 if (v6ops) { 52 if (dev && (mask & XT_ADDRTYPE_LOCAL)) { 53 if (v6ops->chk_addr(net, addr, dev, true)) 54 ret = XT_ADDRTYPE_LOCAL; 55 } 56 route_err = v6ops->route(net, (struct dst_entry **)&rt, 57 flowi6_to_flowi(&flow), false); 58 } else { 59 route_err = 1; 60 } 61 62 if (route_err) 63 return XT_ADDRTYPE_UNREACHABLE; 64 65 if (rt->rt6i_flags & RTF_REJECT) 66 ret = XT_ADDRTYPE_UNREACHABLE; 67 68 if (dev == NULL && rt->rt6i_flags & RTF_LOCAL) 69 ret |= XT_ADDRTYPE_LOCAL; 70 if (ipv6_anycast_destination((struct dst_entry *)rt, addr)) 71 ret |= XT_ADDRTYPE_ANYCAST; 72 73 dst_release(&rt->dst); 74 return ret; 75 } 76 77 static bool match_type6(struct net *net, const struct net_device *dev, 78 const struct in6_addr *addr, u16 mask) 79 { 80 int addr_type = ipv6_addr_type(addr); 81 82 if ((mask & XT_ADDRTYPE_MULTICAST) && 83 !(addr_type & IPV6_ADDR_MULTICAST)) 84 return false; 85 if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST)) 86 return false; 87 if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY) 88 return false; 89 90 if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST | 91 XT_ADDRTYPE_UNREACHABLE) & mask) 92 return !!(mask & match_lookup_rt6(net, dev, addr, mask)); 93 return true; 94 } 95 96 static bool 97 addrtype_mt6(struct net *net, const struct net_device *dev, 98 const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info) 99 { 100 const struct ipv6hdr *iph = ipv6_hdr(skb); 101 bool ret = true; 102 103 if (info->source) 104 ret &= match_type6(net, dev, &iph->saddr, info->source) ^ 105 (info->flags & XT_ADDRTYPE_INVERT_SOURCE); 106 if (ret && info->dest) 107 ret &= match_type6(net, dev, &iph->daddr, info->dest) ^ 108 !!(info->flags & XT_ADDRTYPE_INVERT_DEST); 109 return ret; 110 } 111 #endif 112 113 static inline bool match_type(struct net *net, const struct net_device *dev, 114 __be32 addr, u_int16_t mask) 115 { 116 return !!(mask & (1 << inet_dev_addr_type(net, dev, addr))); 117 } 118 119 static bool 120 addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) 121 { 122 struct net *net = xt_net(par); 123 const struct xt_addrtype_info *info = par->matchinfo; 124 const struct iphdr *iph = ip_hdr(skb); 125 bool ret = true; 126 127 if (info->source) 128 ret &= match_type(net, NULL, iph->saddr, info->source) ^ 129 info->invert_source; 130 if (info->dest) 131 ret &= match_type(net, NULL, iph->daddr, info->dest) ^ 132 info->invert_dest; 133 134 return ret; 135 } 136 137 static bool 138 addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) 139 { 140 struct net *net = xt_net(par); 141 const struct xt_addrtype_info_v1 *info = par->matchinfo; 142 const struct iphdr *iph; 143 const struct net_device *dev = NULL; 144 bool ret = true; 145 146 if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) 147 dev = xt_in(par); 148 else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) 149 dev = xt_out(par); 150 151 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 152 if (xt_family(par) == NFPROTO_IPV6) 153 return addrtype_mt6(net, dev, skb, info); 154 #endif 155 iph = ip_hdr(skb); 156 if (info->source) 157 ret &= match_type(net, dev, iph->saddr, info->source) ^ 158 (info->flags & XT_ADDRTYPE_INVERT_SOURCE); 159 if (ret && info->dest) 160 ret &= match_type(net, dev, iph->daddr, info->dest) ^ 161 !!(info->flags & XT_ADDRTYPE_INVERT_DEST); 162 return ret; 163 } 164 165 static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par) 166 { 167 const char *errmsg = "both incoming and outgoing interface limitation cannot be selected"; 168 struct xt_addrtype_info_v1 *info = par->matchinfo; 169 170 if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN && 171 info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) 172 goto err; 173 174 if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) | 175 (1 << NF_INET_LOCAL_IN)) && 176 info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) { 177 errmsg = "output interface limitation not valid in PREROUTING and INPUT"; 178 goto err; 179 } 180 181 if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) | 182 (1 << NF_INET_LOCAL_OUT)) && 183 info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) { 184 errmsg = "input interface limitation not valid in POSTROUTING and OUTPUT"; 185 goto err; 186 } 187 188 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) 189 if (par->family == NFPROTO_IPV6) { 190 if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) { 191 errmsg = "ipv6 BLACKHOLE matching not supported"; 192 goto err; 193 } 194 if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) { 195 errmsg = "ipv6 PROHIBIT (THROW, NAT ..) matching not supported"; 196 goto err; 197 } 198 if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) { 199 errmsg = "ipv6 does not support BROADCAST matching"; 200 goto err; 201 } 202 } 203 #endif 204 return 0; 205 err: 206 pr_info_ratelimited("%s\n", errmsg); 207 return -EINVAL; 208 } 209 210 static struct xt_match addrtype_mt_reg[] __read_mostly = { 211 { 212 .name = "addrtype", 213 .family = NFPROTO_IPV4, 214 .match = addrtype_mt_v0, 215 .matchsize = sizeof(struct xt_addrtype_info), 216 .me = THIS_MODULE 217 }, 218 { 219 .name = "addrtype", 220 .family = NFPROTO_UNSPEC, 221 .revision = 1, 222 .match = addrtype_mt_v1, 223 .checkentry = addrtype_mt_checkentry_v1, 224 .matchsize = sizeof(struct xt_addrtype_info_v1), 225 .me = THIS_MODULE 226 } 227 }; 228 229 static int __init addrtype_mt_init(void) 230 { 231 return xt_register_matches(addrtype_mt_reg, 232 ARRAY_SIZE(addrtype_mt_reg)); 233 } 234 235 static void __exit addrtype_mt_exit(void) 236 { 237 xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg)); 238 } 239 240 module_init(addrtype_mt_init); 241 module_exit(addrtype_mt_exit); 242