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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
29MODULE_LICENSE("GPL");
30MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
31MODULE_DESCRIPTION("Xtables: address type match");
32MODULE_ALIAS("ipt_addrtype");
33MODULE_ALIAS("ip6t_addrtype");
34
35#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
36static 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
83static 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
102static bool
103addrtype_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
119static 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
125static bool
126addrtype_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
143static bool
144addrtype_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
171static 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 PROHIBT (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
217static 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
236static int __init addrtype_mt_init(void)
237{
238 return xt_register_matches(addrtype_mt_reg,
239 ARRAY_SIZE(addrtype_mt_reg));
240}
241
242static void __exit addrtype_mt_exit(void)
243{
244 xt_unregister_matches(addrtype_mt_reg, ARRAY_SIZE(addrtype_mt_reg));
245}
246
247module_init(addrtype_mt_init);
248module_exit(addrtype_mt_exit);
249
