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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); |