| 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_afinfo *afinfo; |
| 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 | rcu_read_lock(); |
| 51 | |
| 52 | afinfo = nf_get_afinfo(NFPROTO_IPV6); |
| 53 | if (afinfo != NULL) { |
| 54 | const struct nf_ipv6_ops *v6ops; |
| 55 | |
| 56 | if (dev && (mask & XT_ADDRTYPE_LOCAL)) { |
| 57 | v6ops = nf_get_ipv6_ops(); |
| 58 | if (v6ops && v6ops->chk_addr(net, addr, dev, true)) |
| 59 | ret = XT_ADDRTYPE_LOCAL; |
| 60 | } |
| 61 | route_err = afinfo->route(net, (struct dst_entry **)&rt, |
| 62 | flowi6_to_flowi(&flow), false); |
| 63 | } else { |
| 64 | route_err = 1; |
| 65 | } |
| 66 | rcu_read_unlock(); |
| 67 | |
| 68 | if (route_err) |
| 69 | return XT_ADDRTYPE_UNREACHABLE; |
| 70 | |
| 71 | if (rt->rt6i_flags & RTF_REJECT) |
| 72 | ret = XT_ADDRTYPE_UNREACHABLE; |
| 73 | |
| 74 | if (dev == NULL && rt->rt6i_flags & RTF_LOCAL) |
| 75 | ret |= XT_ADDRTYPE_LOCAL; |
| 76 | if (rt->rt6i_flags & RTF_ANYCAST) |
| 77 | ret |= XT_ADDRTYPE_ANYCAST; |
| 78 | |
| 79 | dst_release(&rt->dst); |
| 80 | return ret; |
| 81 | } |
| 82 | |
| 83 | static bool match_type6(struct net *net, const struct net_device *dev, |
| 84 | const struct in6_addr *addr, u16 mask) |
| 85 | { |
| 86 | int addr_type = ipv6_addr_type(addr); |
| 87 | |
| 88 | if ((mask & XT_ADDRTYPE_MULTICAST) && |
| 89 | !(addr_type & IPV6_ADDR_MULTICAST)) |
| 90 | return false; |
| 91 | if ((mask & XT_ADDRTYPE_UNICAST) && !(addr_type & IPV6_ADDR_UNICAST)) |
| 92 | return false; |
| 93 | if ((mask & XT_ADDRTYPE_UNSPEC) && addr_type != IPV6_ADDR_ANY) |
| 94 | return false; |
| 95 | |
| 96 | if ((XT_ADDRTYPE_LOCAL | XT_ADDRTYPE_ANYCAST | |
| 97 | XT_ADDRTYPE_UNREACHABLE) & mask) |
| 98 | return !!(mask & match_lookup_rt6(net, dev, addr, mask)); |
| 99 | return true; |
| 100 | } |
| 101 | |
| 102 | static bool |
| 103 | addrtype_mt6(struct net *net, const struct net_device *dev, |
| 104 | const struct sk_buff *skb, const struct xt_addrtype_info_v1 *info) |
| 105 | { |
| 106 | const struct ipv6hdr *iph = ipv6_hdr(skb); |
| 107 | bool ret = true; |
| 108 | |
| 109 | if (info->source) |
| 110 | ret &= match_type6(net, dev, &iph->saddr, info->source) ^ |
| 111 | (info->flags & XT_ADDRTYPE_INVERT_SOURCE); |
| 112 | if (ret && info->dest) |
| 113 | ret &= match_type6(net, dev, &iph->daddr, info->dest) ^ |
| 114 | !!(info->flags & XT_ADDRTYPE_INVERT_DEST); |
| 115 | return ret; |
| 116 | } |
| 117 | #endif |
| 118 | |
| 119 | static inline bool match_type(struct net *net, const struct net_device *dev, |
| 120 | __be32 addr, u_int16_t mask) |
| 121 | { |
| 122 | return !!(mask & (1 << inet_dev_addr_type(net, dev, addr))); |
| 123 | } |
| 124 | |
| 125 | static bool |
| 126 | addrtype_mt_v0(const struct sk_buff *skb, struct xt_action_param *par) |
| 127 | { |
| 128 | struct net *net = dev_net(par->in ? par->in : par->out); |
| 129 | const struct xt_addrtype_info *info = par->matchinfo; |
| 130 | const struct iphdr *iph = ip_hdr(skb); |
| 131 | bool ret = true; |
| 132 | |
| 133 | if (info->source) |
| 134 | ret &= match_type(net, NULL, iph->saddr, info->source) ^ |
| 135 | info->invert_source; |
| 136 | if (info->dest) |
| 137 | ret &= match_type(net, NULL, iph->daddr, info->dest) ^ |
| 138 | info->invert_dest; |
| 139 | |
| 140 | return ret; |
| 141 | } |
| 142 | |
| 143 | static bool |
| 144 | addrtype_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) |
| 145 | { |
| 146 | struct net *net = dev_net(par->in ? par->in : par->out); |
| 147 | const struct xt_addrtype_info_v1 *info = par->matchinfo; |
| 148 | const struct iphdr *iph; |
| 149 | const struct net_device *dev = NULL; |
| 150 | bool ret = true; |
| 151 | |
| 152 | if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) |
| 153 | dev = par->in; |
| 154 | else if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) |
| 155 | dev = par->out; |
| 156 | |
| 157 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) |
| 158 | if (par->family == NFPROTO_IPV6) |
| 159 | return addrtype_mt6(net, dev, skb, info); |
| 160 | #endif |
| 161 | iph = ip_hdr(skb); |
| 162 | if (info->source) |
| 163 | ret &= match_type(net, dev, iph->saddr, info->source) ^ |
| 164 | (info->flags & XT_ADDRTYPE_INVERT_SOURCE); |
| 165 | if (ret && info->dest) |
| 166 | ret &= match_type(net, dev, iph->daddr, info->dest) ^ |
| 167 | !!(info->flags & XT_ADDRTYPE_INVERT_DEST); |
| 168 | return ret; |
| 169 | } |
| 170 | |
| 171 | static int addrtype_mt_checkentry_v1(const struct xt_mtchk_param *par) |
| 172 | { |
| 173 | struct xt_addrtype_info_v1 *info = par->matchinfo; |
| 174 | |
| 175 | if (info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN && |
| 176 | info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) { |
| 177 | pr_info("both incoming and outgoing " |
| 178 | "interface limitation cannot be selected\n"); |
| 179 | return -EINVAL; |
| 180 | } |
| 181 | |
| 182 | if (par->hook_mask & ((1 << NF_INET_PRE_ROUTING) | |
| 183 | (1 << NF_INET_LOCAL_IN)) && |
| 184 | info->flags & XT_ADDRTYPE_LIMIT_IFACE_OUT) { |
| 185 | pr_info("output interface limitation " |
| 186 | "not valid in PREROUTING and INPUT\n"); |
| 187 | return -EINVAL; |
| 188 | } |
| 189 | |
| 190 | if (par->hook_mask & ((1 << NF_INET_POST_ROUTING) | |
| 191 | (1 << NF_INET_LOCAL_OUT)) && |
| 192 | info->flags & XT_ADDRTYPE_LIMIT_IFACE_IN) { |
| 193 | pr_info("input interface limitation " |
| 194 | "not valid in POSTROUTING and OUTPUT\n"); |
| 195 | return -EINVAL; |
| 196 | } |
| 197 | |
| 198 | #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES) |
| 199 | if (par->family == NFPROTO_IPV6) { |
| 200 | if ((info->source | info->dest) & XT_ADDRTYPE_BLACKHOLE) { |
| 201 | pr_err("ipv6 BLACKHOLE matching not supported\n"); |
| 202 | return -EINVAL; |
| 203 | } |
| 204 | if ((info->source | info->dest) >= XT_ADDRTYPE_PROHIBIT) { |
| 205 | pr_err("ipv6 PROHIBIT (THROW, NAT ..) matching not supported\n"); |
| 206 | return -EINVAL; |
| 207 | } |
| 208 | if ((info->source | info->dest) & XT_ADDRTYPE_BROADCAST) { |
| 209 | pr_err("ipv6 does not support BROADCAST matching\n"); |
| 210 | return -EINVAL; |
| 211 | } |
| 212 | } |
| 213 | #endif |
| 214 | return 0; |
| 215 | } |
| 216 | |
| 217 | static struct xt_match addrtype_mt_reg[] __read_mostly = { |
| 218 | { |
| 219 | .name = "addrtype", |
| 220 | .family = NFPROTO_IPV4, |
| 221 | .match = addrtype_mt_v0, |
| 222 | .matchsize = sizeof(struct xt_addrtype_info), |
| 223 | .me = THIS_MODULE |
| 224 | }, |
| 225 | { |
| 226 | .name = "addrtype", |
| 227 | .family = NFPROTO_UNSPEC, |
| 228 | .revision = 1, |
| 229 | .match = addrtype_mt_v1, |
| 230 | .checkentry = addrtype_mt_checkentry_v1, |
| 231 | .matchsize = sizeof(struct xt_addrtype_info_v1), |
| 232 | .me = THIS_MODULE |
| 233 | } |
| 234 | }; |
| 235 | |
| 236 | static int __init addrtype_mt_init(void) |
| 237 | { |
| 238 | return xt_register_matches(addrtype_mt_reg, |
| 239 | ARRAY_SIZE(addrtype_mt_reg)); |
| 240 | } |
| 241 | |
| 242 | static void __exit addrtype_mt_exit(void) |
| 243 | { |
| 244 | xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg)); |
| 245 | } |
| 246 | |
| 247 | module_init(addrtype_mt_init); |
| 248 | module_exit(addrtype_mt_exit); |