1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C)2003,2004 USAGI/WIDE Project
4 *
5 * Author:
6 * Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
7 */
8
9 #include <linux/types.h>
10 #include <linux/timer.h>
11 #include <linux/module.h>
12 #include <linux/netfilter.h>
13 #include <linux/in6.h>
14 #include <linux/icmpv6.h>
15 #include <linux/ipv6.h>
16 #include <net/ipv6.h>
17 #include <net/ip6_checksum.h>
18 #include <linux/seq_file.h>
19 #include <linux/netfilter_ipv6.h>
20 #include <net/netfilter/nf_conntrack_tuple.h>
21 #include <net/netfilter/nf_conntrack_l4proto.h>
22 #include <net/netfilter/nf_conntrack_core.h>
23 #include <net/netfilter/nf_conntrack_timeout.h>
24 #include <net/netfilter/nf_conntrack_zones.h>
25 #include <net/netfilter/nf_log.h>
26
27 #include "nf_internals.h"
28
29 static const unsigned int nf_ct_icmpv6_timeout = 30*HZ;
30
icmpv6_pkt_to_tuple(const struct sk_buff * skb,unsigned int dataoff,struct net * net,struct nf_conntrack_tuple * tuple)31 bool icmpv6_pkt_to_tuple(const struct sk_buff *skb,
32 unsigned int dataoff,
33 struct net *net,
34 struct nf_conntrack_tuple *tuple)
35 {
36 const struct icmp6hdr *hp;
37 struct icmp6hdr _hdr;
38
39 hp = skb_header_pointer(skb, dataoff, sizeof(_hdr), &_hdr);
40 if (hp == NULL)
41 return false;
42 tuple->dst.u.icmp.type = hp->icmp6_type;
43 tuple->src.u.icmp.id = hp->icmp6_identifier;
44 tuple->dst.u.icmp.code = hp->icmp6_code;
45
46 return true;
47 }
48
49 /* Add 1; spaces filled with 0. */
50 static const u_int8_t invmap[] = {
51 [ICMPV6_ECHO_REQUEST - 128] = ICMPV6_ECHO_REPLY + 1,
52 [ICMPV6_ECHO_REPLY - 128] = ICMPV6_ECHO_REQUEST + 1,
53 [ICMPV6_NI_QUERY - 128] = ICMPV6_NI_REPLY + 1,
54 [ICMPV6_NI_REPLY - 128] = ICMPV6_NI_QUERY + 1
55 };
56
57 static const u_int8_t noct_valid_new[] = {
58 [ICMPV6_MGM_QUERY - 130] = 1,
59 [ICMPV6_MGM_REPORT - 130] = 1,
60 [ICMPV6_MGM_REDUCTION - 130] = 1,
61 [NDISC_ROUTER_SOLICITATION - 130] = 1,
62 [NDISC_ROUTER_ADVERTISEMENT - 130] = 1,
63 [NDISC_NEIGHBOUR_SOLICITATION - 130] = 1,
64 [NDISC_NEIGHBOUR_ADVERTISEMENT - 130] = 1,
65 [ICMPV6_MLD2_REPORT - 130] = 1
66 };
67
nf_conntrack_invert_icmpv6_tuple(struct nf_conntrack_tuple * tuple,const struct nf_conntrack_tuple * orig)68 bool nf_conntrack_invert_icmpv6_tuple(struct nf_conntrack_tuple *tuple,
69 const struct nf_conntrack_tuple *orig)
70 {
71 int type = orig->dst.u.icmp.type - 128;
72 if (type < 0 || type >= sizeof(invmap) || !invmap[type])
73 return false;
74
75 tuple->src.u.icmp.id = orig->src.u.icmp.id;
76 tuple->dst.u.icmp.type = invmap[type] - 1;
77 tuple->dst.u.icmp.code = orig->dst.u.icmp.code;
78 return true;
79 }
80
icmpv6_get_timeouts(struct net * net)81 static unsigned int *icmpv6_get_timeouts(struct net *net)
82 {
83 return &nf_icmpv6_pernet(net)->timeout;
84 }
85
86 /* Returns verdict for packet, or -1 for invalid. */
nf_conntrack_icmpv6_packet(struct nf_conn * ct,struct sk_buff * skb,enum ip_conntrack_info ctinfo,const struct nf_hook_state * state)87 int nf_conntrack_icmpv6_packet(struct nf_conn *ct,
88 struct sk_buff *skb,
89 enum ip_conntrack_info ctinfo,
90 const struct nf_hook_state *state)
91 {
92 unsigned int *timeout = nf_ct_timeout_lookup(ct);
93 static const u8 valid_new[] = {
94 [ICMPV6_ECHO_REQUEST - 128] = 1,
95 [ICMPV6_NI_QUERY - 128] = 1
96 };
97
98 if (state->pf != NFPROTO_IPV6)
99 return -NF_ACCEPT;
100
101 if (!nf_ct_is_confirmed(ct)) {
102 int type = ct->tuplehash[0].tuple.dst.u.icmp.type - 128;
103
104 if (type < 0 || type >= sizeof(valid_new) || !valid_new[type]) {
105 /* Can't create a new ICMPv6 `conn' with this. */
106 pr_debug("icmpv6: can't create new conn with type %u\n",
107 type + 128);
108 nf_ct_dump_tuple_ipv6(&ct->tuplehash[0].tuple);
109 return -NF_ACCEPT;
110 }
111 }
112
113 if (!timeout)
114 timeout = icmpv6_get_timeouts(nf_ct_net(ct));
115
116 /* Do not immediately delete the connection after the first
117 successful reply to avoid excessive conntrackd traffic
118 and also to handle correctly ICMP echo reply duplicates. */
119 nf_ct_refresh_acct(ct, ctinfo, skb, *timeout);
120
121 return NF_ACCEPT;
122 }
123
124
icmpv6_error_log(const struct sk_buff * skb,const struct nf_hook_state * state,const char * msg)125 static void icmpv6_error_log(const struct sk_buff *skb,
126 const struct nf_hook_state *state,
127 const char *msg)
128 {
129 nf_l4proto_log_invalid(skb, state, IPPROTO_ICMPV6, "%s", msg);
130 }
131
132 static noinline_for_stack int
nf_conntrack_icmpv6_redirect(struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,const struct nf_hook_state * state)133 nf_conntrack_icmpv6_redirect(struct nf_conn *tmpl, struct sk_buff *skb,
134 unsigned int dataoff,
135 const struct nf_hook_state *state)
136 {
137 u8 hl = ipv6_hdr(skb)->hop_limit;
138 union nf_inet_addr outer_daddr;
139 union {
140 struct nd_opt_hdr nd_opt;
141 struct rd_msg rd_msg;
142 } tmp;
143 const struct nd_opt_hdr *nd_opt;
144 const struct rd_msg *rd_msg;
145
146 rd_msg = skb_header_pointer(skb, dataoff, sizeof(*rd_msg), &tmp.rd_msg);
147 if (!rd_msg) {
148 icmpv6_error_log(skb, state, "short redirect");
149 return -NF_ACCEPT;
150 }
151
152 if (rd_msg->icmph.icmp6_code != 0)
153 return NF_ACCEPT;
154
155 if (hl != 255 || !(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL)) {
156 icmpv6_error_log(skb, state, "invalid saddr or hoplimit for redirect");
157 return -NF_ACCEPT;
158 }
159
160 dataoff += sizeof(*rd_msg);
161
162 /* warning: rd_msg no longer usable after this call */
163 nd_opt = skb_header_pointer(skb, dataoff, sizeof(*nd_opt), &tmp.nd_opt);
164 if (!nd_opt || nd_opt->nd_opt_len == 0) {
165 icmpv6_error_log(skb, state, "redirect without options");
166 return -NF_ACCEPT;
167 }
168
169 /* We could call ndisc_parse_options(), but it would need
170 * skb_linearize() and a bit more work.
171 */
172 if (nd_opt->nd_opt_type != ND_OPT_REDIRECT_HDR)
173 return NF_ACCEPT;
174
175 memcpy(&outer_daddr.ip6, &ipv6_hdr(skb)->daddr,
176 sizeof(outer_daddr.ip6));
177 dataoff += 8;
178 return nf_conntrack_inet_error(tmpl, skb, dataoff, state,
179 IPPROTO_ICMPV6, &outer_daddr);
180 }
181
nf_conntrack_icmpv6_error(struct nf_conn * tmpl,struct sk_buff * skb,unsigned int dataoff,const struct nf_hook_state * state)182 int nf_conntrack_icmpv6_error(struct nf_conn *tmpl,
183 struct sk_buff *skb,
184 unsigned int dataoff,
185 const struct nf_hook_state *state)
186 {
187 union nf_inet_addr outer_daddr;
188 const struct icmp6hdr *icmp6h;
189 struct icmp6hdr _ih;
190 int type;
191
192 icmp6h = skb_header_pointer(skb, dataoff, sizeof(_ih), &_ih);
193 if (icmp6h == NULL) {
194 icmpv6_error_log(skb, state, "short packet");
195 return -NF_ACCEPT;
196 }
197
198 if (state->hook == NF_INET_PRE_ROUTING &&
199 state->net->ct.sysctl_checksum &&
200 nf_ip6_checksum(skb, state->hook, dataoff, IPPROTO_ICMPV6)) {
201 icmpv6_error_log(skb, state, "ICMPv6 checksum failed");
202 return -NF_ACCEPT;
203 }
204
205 type = icmp6h->icmp6_type - 130;
206 if (type >= 0 && type < sizeof(noct_valid_new) &&
207 noct_valid_new[type]) {
208 nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
209 return NF_ACCEPT;
210 }
211
212 if (icmp6h->icmp6_type == NDISC_REDIRECT)
213 return nf_conntrack_icmpv6_redirect(tmpl, skb, dataoff, state);
214
215 /* is not error message ? */
216 if (icmp6h->icmp6_type >= 128)
217 return NF_ACCEPT;
218
219 memcpy(&outer_daddr.ip6, &ipv6_hdr(skb)->daddr,
220 sizeof(outer_daddr.ip6));
221 dataoff += sizeof(*icmp6h);
222 return nf_conntrack_inet_error(tmpl, skb, dataoff, state,
223 IPPROTO_ICMPV6, &outer_daddr);
224 }
225
226 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
227
228 #include <linux/netfilter/nfnetlink.h>
229 #include <linux/netfilter/nfnetlink_conntrack.h>
icmpv6_tuple_to_nlattr(struct sk_buff * skb,const struct nf_conntrack_tuple * t)230 static int icmpv6_tuple_to_nlattr(struct sk_buff *skb,
231 const struct nf_conntrack_tuple *t)
232 {
233 if (nla_put_be16(skb, CTA_PROTO_ICMPV6_ID, t->src.u.icmp.id) ||
234 nla_put_u8(skb, CTA_PROTO_ICMPV6_TYPE, t->dst.u.icmp.type) ||
235 nla_put_u8(skb, CTA_PROTO_ICMPV6_CODE, t->dst.u.icmp.code))
236 goto nla_put_failure;
237 return 0;
238
239 nla_put_failure:
240 return -1;
241 }
242
243 static const struct nla_policy icmpv6_nla_policy[CTA_PROTO_MAX+1] = {
244 [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
245 [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
246 [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
247 };
248
icmpv6_nlattr_to_tuple(struct nlattr * tb[],struct nf_conntrack_tuple * tuple,u_int32_t flags)249 static int icmpv6_nlattr_to_tuple(struct nlattr *tb[],
250 struct nf_conntrack_tuple *tuple,
251 u_int32_t flags)
252 {
253 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_TYPE)) {
254 if (!tb[CTA_PROTO_ICMPV6_TYPE])
255 return -EINVAL;
256
257 tuple->dst.u.icmp.type = nla_get_u8(tb[CTA_PROTO_ICMPV6_TYPE]);
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
264 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_CODE)) {
265 if (!tb[CTA_PROTO_ICMPV6_CODE])
266 return -EINVAL;
267
268 tuple->dst.u.icmp.code = nla_get_u8(tb[CTA_PROTO_ICMPV6_CODE]);
269 }
270
271 if (flags & CTA_FILTER_FLAG(CTA_PROTO_ICMPV6_ID)) {
272 if (!tb[CTA_PROTO_ICMPV6_ID])
273 return -EINVAL;
274
275 tuple->src.u.icmp.id = nla_get_be16(tb[CTA_PROTO_ICMPV6_ID]);
276 }
277
278 return 0;
279 }
280
icmpv6_nlattr_tuple_size(void)281 static unsigned int icmpv6_nlattr_tuple_size(void)
282 {
283 static unsigned int size __read_mostly;
284
285 if (!size)
286 size = nla_policy_len(icmpv6_nla_policy, CTA_PROTO_MAX + 1);
287
288 return size;
289 }
290 #endif
291
292 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
293
294 #include <linux/netfilter/nfnetlink.h>
295 #include <linux/netfilter/nfnetlink_cttimeout.h>
296
icmpv6_timeout_nlattr_to_obj(struct nlattr * tb[],struct net * net,void * data)297 static int icmpv6_timeout_nlattr_to_obj(struct nlattr *tb[],
298 struct net *net, void *data)
299 {
300 unsigned int *timeout = data;
301 struct nf_icmp_net *in = nf_icmpv6_pernet(net);
302
303 if (!timeout)
304 timeout = icmpv6_get_timeouts(net);
305 if (tb[CTA_TIMEOUT_ICMPV6_TIMEOUT]) {
306 *timeout =
307 ntohl(nla_get_be32(tb[CTA_TIMEOUT_ICMPV6_TIMEOUT])) * HZ;
308 } else {
309 /* Set default ICMPv6 timeout. */
310 *timeout = in->timeout;
311 }
312 return 0;
313 }
314
315 static int
icmpv6_timeout_obj_to_nlattr(struct sk_buff * skb,const void * data)316 icmpv6_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
317 {
318 const unsigned int *timeout = data;
319
320 if (nla_put_be32(skb, CTA_TIMEOUT_ICMPV6_TIMEOUT, htonl(*timeout / HZ)))
321 goto nla_put_failure;
322 return 0;
323
324 nla_put_failure:
325 return -ENOSPC;
326 }
327
328 static const struct nla_policy
329 icmpv6_timeout_nla_policy[CTA_TIMEOUT_ICMPV6_MAX+1] = {
330 [CTA_TIMEOUT_ICMPV6_TIMEOUT] = { .type = NLA_U32 },
331 };
332 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
333
nf_conntrack_icmpv6_init_net(struct net * net)334 void nf_conntrack_icmpv6_init_net(struct net *net)
335 {
336 struct nf_icmp_net *in = nf_icmpv6_pernet(net);
337
338 in->timeout = nf_ct_icmpv6_timeout;
339 }
340
341 const struct nf_conntrack_l4proto nf_conntrack_l4proto_icmpv6 =
342 {
343 .l4proto = IPPROTO_ICMPV6,
344 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
345 .tuple_to_nlattr = icmpv6_tuple_to_nlattr,
346 .nlattr_tuple_size = icmpv6_nlattr_tuple_size,
347 .nlattr_to_tuple = icmpv6_nlattr_to_tuple,
348 .nla_policy = icmpv6_nla_policy,
349 #endif
350 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
351 .ctnl_timeout = {
352 .nlattr_to_obj = icmpv6_timeout_nlattr_to_obj,
353 .obj_to_nlattr = icmpv6_timeout_obj_to_nlattr,
354 .nlattr_max = CTA_TIMEOUT_ICMP_MAX,
355 .obj_size = sizeof(unsigned int),
356 .nla_policy = icmpv6_timeout_nla_policy,
357 },
358 #endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
359 };
360