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 nf_conntrack_tuple *tuple)
40 {
41 const struct icmp6hdr *hp;
42 struct icmp6hdr _hdr;
43
44 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
45 if (hp == NULL)
46 return false;
47 tuple->dst.u.icmp.type = hp->icmp6_type;
48 tuple->src.u.icmp.id = hp->icmp6_identifier;
49 tuple->dst.u.icmp.code = hp->icmp6_code;
50
51 return true;
52 }
53
54 /* Add 1; spaces filled with 0. */
55 static const u_int8_t invmap[] = {
56 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
57 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
58 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
59 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY +1
60 };
61
62 static const u_int8_t noct_valid_new[] = {
63 [ICMPV6_MGM_QUERY - 130] = 1,
64 [ICMPV6_MGM_REPORT -130] = 1,
65 [ICMPV6_MGM_REDUCTION - 130] = 1,
66 [NDISC_ROUTER_SOLICITATION - 130] = 1,
67 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
68 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
69 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
70 [ICMPV6_MLD2_REPORT - 130] = 1
71 };
72
73 static bool icmpv6_invert_tuple(struct nf_conntrack_tuple *tuple,
74 const struct nf_conntrack_tuple *orig)
75 {
76 int type = orig->dst.u.icmp.type - 128;
77 if (type < 0 || type >= sizeof(invmap) || !invmap[type])
78 return false;
79
80 tuple->src.u.icmp.id = orig->src.u.icmp.id;
81 tuple->dst.u.icmp.type = invmap[type] - 1;
82 tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
83 return true;
84 }
85
86 /* Print out the per-protocol part of the tuple. */
87 static void icmpv6_print_tuple(struct seq_file *s,
88 const struct nf_conntrack_tuple *tuple)
89 {
90 seq_printf(s, "type=%u code=%u id=%u ",
91 tuple->dst.u.icmp.type,
92 tuple->dst.u.icmp.code,
93 ntohs(tuple->src.u.icmp.id));
94 }
95
96 static unsigned int *icmpv6_get_timeouts(struct net *net)
97 {
98 return &icmpv6_pernet(net)->timeout;
99 }
100
101 /* Returns verdict for packet, or -1 for invalid. */
102 static int icmpv6_packet(struct nf_conn *ct,
103 const struct sk_buff *skb,
104 unsigned int dataoff,
105 enum ip_conntrack_info ctinfo,
106 u_int8_t pf,
107 unsigned int hooknum,
108 unsigned int *timeout)
109 {
110 /* Do not immediately delete the connection after the first
111 successful reply to avoid excessive conntrackd traffic
112 and also to handle correctly ICMP echo reply duplicates. */
113 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
114
115 return NF_ACCEPT;
116 }
117
118 /* Called when a new connection for this protocol found. */
119 static bool icmpv6_new(struct nf_conn *ct, const struct sk_buff *skb,
120 unsigned int dataoff, unsigned int *timeouts)
121 {
122 static const u_int8_t valid_new[] = {
123 [ICMPV6_ECHO_REQUEST - 128] = 1,
124 [ICMPV6_NI_QUERY - 128] = 1
125 };
126 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
127
128 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
129 /* Can't create a new ICMPv6 `conn' with this. */
130 pr_debug("icmpv6: can't create new conn with type %u\n",
131 type + 128);
132 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
133 if (LOG_INVALID(nf_ct_net(ct), IPPROTO_ICMPV6))
134 nf_log_packet(nf_ct_net(ct), PF_INET6, 0, skb, NULL,
135 NULL, NULL,
136 "nf_ct_icmpv6: invalid new with type %d ",
137 type + 128);
138 return false;
139 }
140 return true;
141 }
142
143 static int
144 icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
145 struct sk_buff *skb,
146 unsigned int icmp6off,
147 enum ip_conntrack_info *ctinfo,
148 unsigned int hooknum)
149 {
150 struct nf_conntrack_tuple intuple, origtuple;
151 const struct nf_conntrack_tuple_hash *h;
152 const struct nf_conntrack_l4proto *inproto;
153 u16 zone = tmpl ? nf_ct_zone(tmpl) : NF_CT_DEFAULT_ZONE;
154
155 NF_CT_ASSERT(skb->nfct == NULL);
156
157 /* Are they talking about one of our connections? */
158 if (!nf_ct_get_tuplepr(skb,
159 skb_network_offset(skb)
160 + sizeof(struct ipv6hdr)
161 + sizeof(struct icmp6hdr),
162 PF_INET6, &origtuple)) {
163 pr_debug("icmpv6_error: Can't get tuple\n");
164 return -NF_ACCEPT;
165 }
166
167 /* rcu_read_lock()ed by nf_hook_slow */
168 inproto = __nf_ct_l4proto_find(PF_INET6, origtuple.dst.protonum);
169
170 /* Ordinarily, we'd expect the inverted tupleproto, but it's
171 been preserved inside the ICMP. */
172 if (!nf_ct_invert_tuple(&intuple, &origtuple,
173 &nf_conntrack_l3proto_ipv6, inproto)) {
174 pr_debug("icmpv6_error: Can't invert tuple\n");
175 return -NF_ACCEPT;
176 }
177
178 *ctinfo = IP_CT_RELATED;
179
180 h = nf_conntrack_find_get(net, zone, &intuple);
181 if (!h) {
182 pr_debug("icmpv6_error: no match\n");
183 return -NF_ACCEPT;
184 } else {
185 if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
186 *ctinfo += IP_CT_IS_REPLY;
187 }
188
189 /* Update skb to refer to this connection */
190 skb->nfct = &nf_ct_tuplehash_to_ctrack(h)->ct_general;
191 skb->nfctinfo = *ctinfo;
192 return NF_ACCEPT;
193 }
194
195 static int
196 icmpv6_error(struct net *net, struct nf_conn *tmpl,
197 struct sk_buff *skb, unsigned int dataoff,
198 enum ip_conntrack_info *ctinfo, u_int8_t pf, unsigned int hooknum)
199 {
200 const struct icmp6hdr *icmp6h;
201 struct icmp6hdr _ih;
202 int type;
203
204 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
205 if (icmp6h == NULL) {
206 if (LOG_INVALID(net, IPPROTO_ICMPV6))
207 nf_log_packet(net, PF_INET6, 0, skb, NULL, NULL, NULL,
208 "nf_ct_icmpv6: short packet ");
209 return -NF_ACCEPT;
210 }
211
212 if (net->ct.sysctl_checksum && hooknum == NF_INET_PRE_ROUTING &&
213 nf_ip6_checksum(skb, hooknum, dataoff, IPPROTO_ICMPV6)) {
214 if (LOG_INVALID(net, IPPROTO_ICMPV6))
215 nf_log_packet(net, PF_INET6, 0, skb, NULL, NULL, NULL,
216 "nf_ct_icmpv6: ICMPv6 checksum failed ");
217 return -NF_ACCEPT;
218 }
219
220 type = icmp6h->icmp6_type - 130;
221 if (type >= 0 && type < sizeof(noct_valid_new) &&
222 noct_valid_new[type]) {
223 skb->nfct = &nf_ct_untracked_get()->ct_general;
224 skb->nfctinfo = IP_CT_NEW;
225 nf_conntrack_get(skb->nfct);
226 return NF_ACCEPT;
227 }
228
229 /* is not error message ? */
230 if (icmp6h->icmp6_type >= 128)
231 return NF_ACCEPT;
232
233 return icmpv6_error_message(net, tmpl, skb, dataoff, ctinfo, hooknum);
234 }
235
236 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
237
238 #include <linux/netfilter/nfnetlink.h>
239 #include <linux/netfilter/nfnetlink_conntrack.h>
240 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
241 const struct nf_conntrack_tuple *t)
242 {
243 if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
244 nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
245 nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
246 goto nla_put_failure;
247 return 0;
248
249 nla_put_failure:
250 return -1;
251 }
252
253 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
254 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
255 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
256 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
257 };
258
259 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
260 struct nf_conntrack_tuple *tuple)
261 {
262 if (!tb[CTA_PROTO_ICMPV6_TYPE] ||
263 !tb[CTA_PROTO_ICMPV6_CODE] ||
264 !tb[CTA_PROTO_ICMPV6_ID])
265 return -EINVAL;
266
267 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
268 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
269 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
270
271 if (tuple->dst.u.icmp.type < 128 ||
272 tuple->dst.u.icmp.type - 128 >= sizeof(invmap) ||
273 !invmap[tuple->dst.u.icmp.type - 128])
274 return -EINVAL;
275
276 return 0;
277 }
278
279 static int icmpv6_nlattr_tuple_size(void)
280 {
281 return nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
282 }
283 #endif
284
285 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
286
287 #include <linux/netfilter/nfnetlink.h>
288 #include <linux/netfilter/nfnetlink_cttimeout.h>
289
290 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
291 struct net *net, void *data)
292 {
293 unsigned int *timeout = data;
294 struct nf_icmp_net *in = icmpv6_pernet(net);
295
296 if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
297 *timeout =
298 ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
299 } else {
300 /* Set default ICMPv6 timeout. */
301 *timeout = in->timeout;
302 }
303 return 0;
304 }
305
306 static int
307 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
308 {
309 const unsigned int *timeout = data;
310
311 if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
312 goto nla_put_failure;
313 return 0;
314
315 nla_put_failure:
316 return -ENOSPC;
317 }
318
319 static const struct nla_policy
320 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
321 [CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
322 };
323 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
324
325 #ifdef CONFIG_SYSCTL
326 static struct ctl_table icmpv6_sysctl_table[] = {
327 {
328 .procname = "nf_conntrack_icmpv6_timeout",
329 .maxlen = sizeof(unsigned int),
330 .mode = 0644,
331 .proc_handler = proc_dointvec_jiffies,
332 },
333 { }
334 };
335 #endif /* CONFIG_SYSCTL */
336
337 static int icmpv6_kmemdup_sysctl_table(struct nf_proto_net *pn,
338 struct nf_icmp_net *in)
339 {
340 #ifdef CONFIG_SYSCTL
341 pn->ctl_table = kmemdup(icmpv6_sysctl_table,
342 sizeof(icmpv6_sysctl_table),
343 GFP_KERNEL);
344 if (!pn->ctl_table)
345 return -ENOMEM;
346
347 pn->ctl_table[0].data = &in->timeout;
348 #endif
349 return 0;
350 }
351
352 static int icmpv6_init_net(struct net *net, u_int16_t proto)
353 {
354 struct nf_icmp_net *in = icmpv6_pernet(net);
355 struct nf_proto_net *pn = &in->pn;
356
357 in->timeout = nf_ct_icmpv6_timeout;
358
359 return icmpv6_kmemdup_sysctl_table(pn, in);
360 }
361
362 static struct nf_proto_net *icmpv6_get_net_proto(struct net *net)
363 {
364 return &net->ct.nf_ct_proto.icmpv6.pn;
365 }
366
367 struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 __read_mostly =
368 {
369 .l3proto = PF_INET6,
370 .l4proto = IPPROTO_ICMPV6,
371 .name = "icmpv6",
372 .pkt_to_tuple = icmpv6_pkt_to_tuple,
373 .invert_tuple = icmpv6_invert_tuple,
374 .print_tuple = icmpv6_print_tuple,
375 .packet = icmpv6_packet,
376 .get_timeouts = icmpv6_get_timeouts,
377 .new = icmpv6_new,
378 .error = icmpv6_error,
379 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
380 .tuple_to_nlattr = icmpv6_tuple_to_nlattr,
381 .nlattr_tuple_size = icmpv6_nlattr_tuple_size,
382 .nlattr_to_tuple = icmpv6_nlattr_to_tuple,
383 .nla_policy = icmpv6_nla_policy,
384 #endif
385 #if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
386 .ctnl_timeout = {
387 .nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
388 .obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
389 .nlattr_max = CTA_TIMEOUT_ICMP_MAX,
390 .obj_size = sizeof(unsigned int),
391 .nla_policy = icmpv6_timeout_nla_policy,
392 },
393 #endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
394 .init_net = icmpv6_init_net,
395 .get_net_proto = icmpv6_get_net_proto,
396 };
397
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