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_zones.h>
27 #include <net/netfilter/ipv6/nf_conntrack_icmpv6.h>
28 #include <net/netfilter/nf_log.h>
29
30 static unsigned int nf_ct_icmpv6_timeout __read_mostly = 30*HZ;
31
32 static inline struct nf_icmp_net *icmpv6_pernet(struct net *net)
33 {
34 return &net->ct.nf_ct_proto.icmpv6;
35 }
36
37 static bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
38 unsigned int dataoff,
39 struct net *net,
40 struct nf_conntrack_tuple *tuple)
41 {
42 const struct icmp6hdr *hp;
43 struct icmp6hdr _hdr;
44
45 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
46 if (hp == NULL)
47 return false;
48 tuple->dst.u.icmp.type = hp->icmp6_type;
49 tuple->src.u.icmp.id = hp->icmp6_identifier;
50 tuple->dst.u.icmp.code = hp->icmp6_code;
51
52 return true;
53 }
54
55 /* Add 1; spaces filled with 0. */
56 static const u_int8_t invmap[] = {
57 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
58 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
59 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
60 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1
61 };
62
63 static const u_int8_t noct_valid_new[] = {
64 [ICMPV6_MGM_QUERY - 130] = 1,
65 [ICMPV6_MGM_REPORT - 130] = 1,
66 [ICMPV6_MGM_REDUCTION - 130] = 1,
67 [NDISC_ROUTER_SOLICITATION - 130] = 1,
68 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
69 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
70 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
71 [ICMPV6_MLD2_REPORT - 130] = 1
72 };
73
74 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
75 const struct nf_conntrack_tuple *orig)
76 {
77 int type = orig->dst.u.icmp.type - 128;
78 if (type < 0 || type >= sizeof(invmap) || !invmap[type])
79 return false;
80
81 tuple->src.u.icmp.id = orig->src.u.icmp.id;
82 tuple->dst.u.icmp.type = invmap[type] - 1;
83 tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
84 return true;
85 }
86
87 /* Print out the per-protocol part of the tuple. */
88 static void icmpv6_print_tuple(struct seq_file *s,
89 const struct nf_conntrack_tuple *tuple)
90 {
91 seq_printf(s, "type=%u code=%u id=%u ",
92 tuple->dst.u.icmp.type,
93 tuple->dst.u.icmp.code,
94 ntohs(tuple->src.u.icmp.id));
95 }
96
97 static unsigned int *icmpv6_get_timeouts(struct net *net)
98 {
99 return &icmpv6_pernet(net)->timeout;
100 }
101
102 /* Returns verdict for packet, or -1 for invalid. */
103 static int icmpv6_packet(struct nf_conn *ct,
104 const struct sk_buff *skb,
105 unsigned int dataoff,
106 enum ip_conntrack_info ctinfo,
107 u_int8_t pf,
108 unsigned int hooknum,
109 unsigned int *timeout)
110 {
111 /* Do not immediately delete the connection after the first
112 successful reply to avoid excessive conntrackd traffic
113 and also to handle correctly ICMP echo reply duplicates. */
114 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
115
116 return NF_ACCEPT;
117 }
118
119 /* Called when a new connection for this protocol found. */
120 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
121 unsigned int dataoff, unsigned int *timeouts)
122 {
123 static const u_int8_t valid_new[] = {
124 [ICMPV6_ECHO_REQUEST - 128] = 1,
125 [ICMPV6_NI_QUERY - 128] = 1
126 };
127 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
128
129 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
130 /* Can't create a new ICMPv6 `conn' with this. */
131 pr_debug("icmpv6: can't create new conn with type %u\n",
132 type + 128);
133 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
134 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
135 nf_log_packet(nf_ct_net(ct), PF_INET6, 0, skb, NULL,
136 NULL, NULL,
137 "nf_ct_icmpv6: invalid new with type %d ",
138 type + 128);
139 return false;
140 }
141 return true;
142 }
143
144 static int
145 icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
146 struct sk_buff *skb,
147 unsigned int icmp6off,
148 enum ip_conntrack_info *ctinfo,
149 unsigned int hooknum)
150 {
151 struct nf_conntrack_tuple intuple, origtuple;
152 const struct nf_conntrack_tuple_hash *h;
153 const struct nf_conntrack_l4proto *inproto;
154 struct nf_conntrack_zone tmp;
155
156 NF_CT_ASSERT(skb->nfct == NULL);
157
158 /* Are they talking about one of our connections? */
159 if (!nf_ct_get_tuplepr(skb,
160 skb_network_offset(skb)
161 + sizeof(struct ipv6hdr)
162 + sizeof(struct icmp6hdr),
163 PF_INET6, net, &origtuple)) {
164 pr_debug("icmpv6_error: Can't get tuple\n");
165 return -NF_ACCEPT;
166 }
167
168 /* rcu_read_lock()ed by nf_hook_slow */
169 inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
170
171 /* Ordinarily, we'd expect the inverted tupleproto, but it's
172 been preserved inside the ICMP. */
173 if (!nf_ct_invert_tuple(&intuple, &origtuple,
174 &nf_conntrack_l3proto_ipv6, inproto)) {
175 pr_debug("icmpv6_error: Can't invert tuple\n");
176 return -NF_ACCEPT;
177 }
178
179 *ctinfo = IP_CT_RELATED;
180
181 h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
182 &intuple);
183 if (!h) {
184 pr_debug("icmpv6_error: no match\n");
185 return -NF_ACCEPT;
186 } else {
187 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
188 *ctinfo += IP_CT_IS_REPLY;
189 }
190
191 /* Update skb to refer to this connection */
192 skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
193 skb->nfctinfo = *ctinfo;
194 return NF_ACCEPT;
195 }
196
197 static int
198 icmpv6_error(struct net *net, struct nf_conn *tmpl,
199 struct sk_buff *skb, unsigned int dataoff,
200 enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
201 {
202 const struct icmp6hdr *icmp6h;
203 struct icmp6hdr _ih;
204 int type;
205
206 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
207 if (icmp6h == NULL) {
208 if (LOG_INVALID(net, IPPROTO_ICMPV6))
209 nf_log_packet(net, PF_INET6, 0, skb, NULL, NULL, NULL,
210 "nf_ct_icmpv6: short packet ");
211 return -NF_ACCEPT;
212 }
213
214 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
215 nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
216 if (LOG_INVALID(net, IPPROTO_ICMPV6))
217 nf_log_packet(net, PF_INET6, 0, skb, NULL, NULL, NULL,
218 "nf_ct_icmpv6: ICMPv6 checksum failed ");
219 return -NF_ACCEPT;
220 }
221
222 type = icmp6h->icmp6_type - 130;
223 if (type >= 0 && type < sizeof(noct_valid_new) &&
224 noct_valid_new[type]) {
225 skb->nfct = &nf_ct_untracked_get()->ct_general;
226 skb->nfctinfo = IP_CT_NEW;
227 nf_conntrack_get(skb->nfct);
228 return NF_ACCEPT;
229 }
230
231 /* is not error message ? */
232 if (icmp6h->icmp6_type >= 128)
233 return NF_ACCEPT;
234
235 return icmpv6_error_message(net, tmpl, skb, dataoff, ctinfo, hooknum);
236 }
237
238 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
239
240 #include <linux/netfilter/nfnetlink.h>
241 #include <linux/netfilter/nfnetlink_conntrack.h>
242 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
243 const struct nf_conntrack_tuple *t)
244 {
245 if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
246 nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
247 nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
248 goto nla_put_failure;
249 return 0;
250
251 nla_put_failure:
252 return -1;
253 }
254
255 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
256 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
257 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
258 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
259 };
260
261 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
262 struct nf_conntrack_tuple *tuple)
263 {
264 if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
265 !tb[CTA_PROTO_ICMPV6_CODE] ||
266 !tb[CTA_PROTO_ICMPV6_ID])
267 return -EINVAL;
268
269 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
270 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
271 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
272
273 if (tuple->dst.u.icmp.type < 128 ||
274 tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
275 !invmap[tuple->dst.u.icmp.type - 128])
276 return -EINVAL;
277
278 return 0;
279 }
280
281 static int icmpv6_nlattr_tuple_size(void)
282 {
283 return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
284 }
285 #endif
286
287 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
288
289 #include <linux/netfilter/nfnetlink.h>
290 #include <linux/netfilter/nfnetlink_cttimeout.h>
291
292 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
293 struct net *net, void *data)
294 {
295 unsigned int *timeout = data;
296 struct nf_icmp_net *in = icmpv6_pernet(net);
297
298 if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
299 *timeout =
300 ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
301 } else {
302 /* Set default ICMPv6 timeout. */
303 *timeout = in->timeout;
304 }
305 return 0;
306 }
307
308 static int
309 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
310 {
311 const unsigned int *timeout = data;
312
313 if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
314 goto nla_put_failure;
315 return 0;
316
317 nla_put_failure:
318 return -ENOSPC;
319 }
320
321 static const struct nla_policy
322 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
323 [CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
324 };
325 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
326
327 #ifdef CONFIG_SYSCTL
328 static struct ctl_table icmpv6_sysctl_table[] = {
329 {
330 .procname = "nf_conntrack_icmpv6_timeout",
331 .maxlen = sizeof(unsigned int),
332 .mode = 0644,
333 .proc_handler = proc_dointvec_jiffies,
334 },
335 { }
336 };
337 #endif /* CONFIG_SYSCTL */
338
339 static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
340 struct nf_icmp_net *in)
341 {
342 #ifdef CONFIG_SYSCTL
343 pn->ctl_table = kmemdup(icmpv6_sysctl_table,
344 sizeof(icmpv6_sysctl_table),
345 GFP_KERNEL);
346 if (!pn->ctl_table)
347 return -ENOMEM;
348
349 pn->ctl_table[0].data = &in->timeout;
350 #endif
351 return 0;
352 }
353
354 static int icmpv6_init_net(struct net *net, u_int16_t proto)
355 {
356 struct nf_icmp_net *in = icmpv6_pernet(net);
357 struct nf_proto_net *pn = &in->pn;
358
359 in->timeout = nf_ct_icmpv6_timeout;
360
361 return icmpv6_kmemdup_sysctl_table(pn, in);
362 }
363
364 static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
365 {
366 return &net->ct.nf_ct_proto.icmpv6.pn;
367 }
368
369 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
370 {
371 .l3proto = PF_INET6,
372 .l4proto = IPPROTO_ICMPV6,
373 .name = "icmpv6",
374 .pkt_to_tuple = icmpv6_pkt_to_tuple,
375 .invert_tuple = icmpv6_invert_tuple,
376 .print_tuple = icmpv6_print_tuple,
377 .packet = icmpv6_packet,
378 .get_timeouts = icmpv6_get_timeouts,
379 .new = icmpv6_new,
380 .error = icmpv6_error,
381 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
382 .tuple_to_nlattr = icmpv6_tuple_to_nlattr,
383 .nlattr_tuple_size = icmpv6_nlattr_tuple_size,
384 .nlattr_to_tuple = icmpv6_nlattr_to_tuple,
385 .nla_policy = icmpv6_nla_policy,
386 #endif
387 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
388 .ctnl_timeout = {
389 .nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
390 .obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
391 .nlattr_max = CTA_TIMEOUT_ICMP_MAX,
392 .obj_size = sizeof(unsigned int),
393 .nla_policy = icmpv6_timeout_nla_policy,
394 },
395 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
396 .init_net = icmpv6_init_net,
397 .get_net_proto = icmpv6_get_net_proto,
398 };
399
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