1 /*
2 * Copyright (C)2003,2004 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * Author:
9 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
10 */
11
12 #include <linux/types.h>
13 #include <linux/timer.h>
14 #include <linux/module.h>
15 #include <linux/netfilter.h>
16 #include <linux/in6.h>
17 #include <linux/icmpv6.h>
18 #include <linux/ipv6.h>
19 #include <net/ipv6.h>
20 #include <net/ip6_checksum.h>
21 #include <linux/seq_file.h>
22 #include <linux/netfilter_ipv6.h>
23 #include <net/netfilter/nf_conntrack_tuple.h>
24 #include <net/netfilter/nf_conntrack_l4proto.h>
25 #include <net/netfilter/nf_conntrack_core.h>
26 #include <net/netfilter/nf_conntrack_timeout.h>
27 #include <net/netfilter/nf_conntrack_zones.h>
28 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
29 #include <net/netfilter/nf_log.h>
30
31 static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;
32
icmpv6_pernet(struct net * net)33 static inline struct nf_icmp_net *icmpv6_pernet(struct net *net)
34 {
35 return &net->ct.nf_ct_proto.icmpv6;
36 }
37
icmpv6_pkt_to_tuple(const struct sk_buff * skb,unsigned int dataoff,struct net * net,struct nf_conntrack_tuple * tuple)38 static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
39 unsigned int dataoff,
40 struct net *net,
41 struct nf_conntrack_tuple *tuple)
42 {
43 const struct icmp6hdr *hp;
44 struct icmp6hdr _hdr;
45
46 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
47 if (hp == NULL)
48 return false;
49 tuple->dst.u.icmp.type = hp->icmp6_type;
50 tuple->src.u.icmp.id = hp->icmp6_identifier;
51 tuple->dst.u.icmp.code = hp->icmp6_code;
52
53 return true;
54 }
55
56 /* Add 1; spaces filled with 0. */
57 static const u_int8_t invmap[] = {
58 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
59 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
60 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
61 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1
62 };
63
64 static const u_int8_t noct_valid_new[] = {
65 [ICMPV6_MGM_QUERY - 130] = 1,
66 [ICMPV6_MGM_REPORT - 130] = 1,
67 [ICMPV6_MGM_REDUCTION - 130] = 1,
68 [NDISC_ROUTER_SOLICITATION - 130] = 1,
69 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
70 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
71 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
72 [ICMPV6_MLD2_REPORT - 130] = 1
73 };
74
icmpv6_invert_tuple(struct nf_conntrack_tuple * tuple,const struct nf_conntrack_tuple * orig)75 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
76 const struct nf_conntrack_tuple *orig)
77 {
78 int type = orig->dst.u.icmp.type - 128;
79 if (type < 0 || type >= sizeof(invmap) || !invmap[type])
80 return false;
81
82 tuple->src.u.icmp.id = orig->src.u.icmp.id;
83 tuple->dst.u.icmp.type = invmap[type] - 1;
84 tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
85 return true;
86 }
87
icmpv6_get_timeouts(struct net * net)88 static unsigned int *icmpv6_get_timeouts(struct net *net)
89 {
90 return &icmpv6_pernet(net)->timeout;
91 }
92
93 /* Returns verdict for packet, or -1 for invalid. */
icmpv6_packet(struct nf_conn * ct,const struct sk_buff * skb,unsigned int dataoff,enum ip_conntrack_info ctinfo)94 static int icmpv6_packet(struct nf_conn *ct,
95 const struct sk_buff *skb,
96 unsigned int dataoff,
97 enum ip_conntrack_info ctinfo)
98 {
99 unsigned int *timeout = nf_ct_timeout_lookup(ct);
100
101 if (!timeout)
102 timeout = icmpv6_get_timeouts(nf_ct_net(ct));
103
104 /* Do not immediately delete the connection after the first
105 successful reply to avoid excessive conntrackd traffic
106 and also to handle correctly ICMP echo reply duplicates. */
107 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
108
109 return NF_ACCEPT;
110 }
111
112 /* Called when a new connection for this protocol found. */
icmpv6_new(struct nf_conn * ct,const struct sk_buff * skb,unsigned int dataoff)113 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
114 unsigned int dataoff)
115 {
116 static const u_int8_t valid_new[] = {
117 [ICMPV6_ECHO_REQUEST - 128] = 1,
118 [ICMPV6_NI_QUERY - 128] = 1
119 };
120 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
121
122 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
123 /* Can't create a new ICMPv6 `conn' with this. */
124 pr_debug("icmpv6: can't create new conn with type %u\n",
125 type + 128);
126 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
127 return false;
128 }
129 return true;
130 }
131
132 static int
icmpv6_error_message(struct net * net,struct nf_conn * tmpl,struct sk_buff * skb,unsigned int icmp6off)133 icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
134 struct sk_buff *skb,
135 unsigned int icmp6off)
136 {
137 struct nf_conntrack_tuple intuple, origtuple;
138 const struct nf_conntrack_tuple_hash *h;
139 const struct nf_conntrack_l4proto *inproto;
140 enum ip_conntrack_info ctinfo;
141 struct nf_conntrack_zone tmp;
142
143 WARN_ON(skb_nfct(skb));
144
145 /* Are they talking about one of our connections? */
146 if (!nf_ct_get_tuplepr(skb,
147 skb_network_offset(skb)
148 + sizeof(struct ipv6hdr)
149 + sizeof(struct icmp6hdr),
150 PF_INET6, net, &origtuple)) {
151 pr_debug("icmpv6_error: Can't get tuple\n");
152 return -NF_ACCEPT;
153 }
154
155 /* rcu_read_lock()ed by nf_hook_thresh */
156 inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
157
158 /* Ordinarily, we'd expect the inverted tupleproto, but it's
159 been preserved inside the ICMP. */
160 if (!nf_ct_invert_tuple(&intuple, &origtuple, inproto)) {
161 pr_debug("icmpv6_error: Can't invert tuple\n");
162 return -NF_ACCEPT;
163 }
164
165 ctinfo = IP_CT_RELATED;
166
167 h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
168 &intuple);
169 if (!h) {
170 pr_debug("icmpv6_error: no match\n");
171 return -NF_ACCEPT;
172 } else {
173 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
174 ctinfo += IP_CT_IS_REPLY;
175 }
176
177 /* Update skb to refer to this connection */
178 nf_ct_set(skb, nf_ct_tuplehash_to_ctrack(h), ctinfo);
179 return NF_ACCEPT;
180 }
181
icmpv6_error_log(const struct sk_buff * skb,struct net * net,u8 pf,const char * msg)182 static void icmpv6_error_log(const struct sk_buff *skb, struct net *net,
183 u8 pf, const char *msg)
184 {
185 nf_l4proto_log_invalid(skb, net, pf, IPPROTO_ICMPV6, "%s", msg);
186 }
187
188 static int
icmpv6_error(struct net * net,struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,u8 pf,unsigned int hooknum)189 icmpv6_error(struct net *net, struct nf_conn *tmpl,
190 struct sk_buff *skb, unsigned int dataoff,
191 u8 pf, unsigned int hooknum)
192 {
193 const struct icmp6hdr *icmp6h;
194 struct icmp6hdr _ih;
195 int type;
196
197 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
198 if (icmp6h == NULL) {
199 icmpv6_error_log(skb, net, pf, "short packet");
200 return -NF_ACCEPT;
201 }
202
203 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
204 nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
205 icmpv6_error_log(skb, net, pf, "ICMPv6 checksum failed");
206 return -NF_ACCEPT;
207 }
208
209 type = icmp6h->icmp6_type - 130;
210 if (type >= 0 && type < sizeof(noct_valid_new) &&
211 noct_valid_new[type]) {
212 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
213 return NF_ACCEPT;
214 }
215
216 /* is not error message ? */
217 if (icmp6h->icmp6_type >= 128)
218 return NF_ACCEPT;
219
220 return icmpv6_error_message(net, tmpl, skb, dataoff);
221 }
222
223 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
224
225 #include <linux/netfilter/nfnetlink.h>
226 #include <linux/netfilter/nfnetlink_conntrack.h>
icmpv6_tuple_to_nlattr(struct sk_buff * skb,const struct nf_conntrack_tuple * t)227 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
228 const struct nf_conntrack_tuple *t)
229 {
230 if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
231 nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
232 nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
233 goto nla_put_failure;
234 return 0;
235
236 nla_put_failure:
237 return -1;
238 }
239
240 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
241 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
242 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
243 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
244 };
245
icmpv6_nlattr_to_tuple(struct nlattr * tb[],struct nf_conntrack_tuple * tuple)246 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
247 struct nf_conntrack_tuple *tuple)
248 {
249 if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
250 !tb[CTA_PROTO_ICMPV6_CODE] ||
251 !tb[CTA_PROTO_ICMPV6_ID])
252 return -EINVAL;
253
254 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
255 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
256 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
257
258 if (tuple->dst.u.icmp.type < 128 ||
259 tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
260 !invmap[tuple->dst.u.icmp.type - 128])
261 return -EINVAL;
262
263 return 0;
264 }
265
icmpv6_nlattr_tuple_size(void)266 static unsigned int icmpv6_nlattr_tuple_size(void)
267 {
268 static unsigned int size __read_mostly;
269
270 if (!size)
271 size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
272
273 return size;
274 }
275 #endif
276
277 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
278
279 #include <linux/netfilter/nfnetlink.h>
280 #include <linux/netfilter/nfnetlink_cttimeout.h>
281
icmpv6_timeout_nlattr_to_obj(struct nlattr * tb[],struct net * net,void * data)282 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
283 struct net *net, void *data)
284 {
285 unsigned int *timeout = data;
286 struct nf_icmp_net *in = icmpv6_pernet(net);
287
288 if (!timeout)
289 timeout = icmpv6_get_timeouts(net);
290 if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
291 *timeout =
292 ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
293 } else {
294 /* Set default ICMPv6 timeout. */
295 *timeout = in->timeout;
296 }
297 return 0;
298 }
299
300 static int
icmpv6_timeout_obj_to_nlattr(struct sk_buff * skb,const void * data)301 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
302 {
303 const unsigned int *timeout = data;
304
305 if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
306 goto nla_put_failure;
307 return 0;
308
309 nla_put_failure:
310 return -ENOSPC;
311 }
312
313 static const struct nla_policy
314 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
315 [CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
316 };
317 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
318
319 #ifdef CONFIG_SYSCTL
320 static struct ctl_table icmpv6_sysctl_table[] = {
321 {
322 .procname = "nf_conntrack_icmpv6_timeout",
323 .maxlen = sizeof(unsigned int),
324 .mode = 0644,
325 .proc_handler = proc_dointvec_jiffies,
326 },
327 { }
328 };
329 #endif /* CONFIG_SYSCTL */
330
icmpv6_kmemdup_sysctl_table(struct nf_proto_net * pn,struct nf_icmp_net * in)331 static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
332 struct nf_icmp_net *in)
333 {
334 #ifdef CONFIG_SYSCTL
335 pn->ctl_table = kmemdup(icmpv6_sysctl_table,
336 sizeof(icmpv6_sysctl_table),
337 GFP_KERNEL);
338 if (!pn->ctl_table)
339 return -ENOMEM;
340
341 pn->ctl_table[0].data = &in->timeout;
342 #endif
343 return 0;
344 }
345
icmpv6_init_net(struct net * net,u_int16_t proto)346 static int icmpv6_init_net(struct net *net, u_int16_t proto)
347 {
348 struct nf_icmp_net *in = icmpv6_pernet(net);
349 struct nf_proto_net *pn = &in->pn;
350
351 in->timeout = nf_ct_icmpv6_timeout;
352
353 return icmpv6_kmemdup_sysctl_table(pn, in);
354 }
355
icmpv6_get_net_proto(struct net * net)356 static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
357 {
358 return &net->ct.nf_ct_proto.icmpv6.pn;
359 }
360
361 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
362 {
363 .l3proto = PF_INET6,
364 .l4proto = IPPROTO_ICMPV6,
365 .pkt_to_tuple = icmpv6_pkt_to_tuple,
366 .invert_tuple = icmpv6_invert_tuple,
367 .packet = icmpv6_packet,
368 .new = icmpv6_new,
369 .error = icmpv6_error,
370 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
371 .tuple_to_nlattr = icmpv6_tuple_to_nlattr,
372 .nlattr_tuple_size = icmpv6_nlattr_tuple_size,
373 .nlattr_to_tuple = icmpv6_nlattr_to_tuple,
374 .nla_policy = icmpv6_nla_policy,
375 #endif
376 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
377 .ctnl_timeout = {
378 .nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
379 .obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
380 .nlattr_max = CTA_TIMEOUT_ICMP_MAX,
381 .obj_size = sizeof(unsigned int),
382 .nla_policy = icmpv6_timeout_nla_policy,
383 },
384 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
385 .init_net = icmpv6_init_net,
386 .get_net_proto = icmpv6_get_net_proto,
387 };
388
