2 * ipsecmod/ipsecmod.c - facilitate opportunistic IPsec module
4 * Copyright (c) 2017, NLnet Labs. All rights reserved.
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39 * This file contains a module that facilitates opportunistic IPsec. It does so
40 * by also quering for the IPSECKEY for A/AAAA queries and calling a
41 * configurable hook (eg. signaling an IKE daemon) before replying.
46 #include "ipsecmod/ipsecmod.h"
47 #include "ipsecmod/ipsecmod-whitelist.h"
48 #include "util/fptr_wlist.h"
49 #include "util/regional.h"
50 #include "util/net_help.h"
51 #include "util/config_file.h"
52 #include "services/cache/dns.h"
53 #include "sldns/wire2str.h"
55 /** Apply configuration to ipsecmod module 'global' state. */
57 ipsecmod_apply_cfg(struct ipsecmod_env* ipsecmod_env, struct config_file* cfg)
59 if(!cfg->ipsecmod_hook || (cfg->ipsecmod_hook && !cfg->ipsecmod_hook[0])) {
60 log_err("ipsecmod: missing ipsecmod-hook.");
63 if(cfg->ipsecmod_whitelist &&
64 !ipsecmod_whitelist_apply_cfg(ipsecmod_env, cfg))
70 ipsecmod_init(struct module_env* env, int id)
72 struct ipsecmod_env* ipsecmod_env = (struct ipsecmod_env*)calloc(1,
73 sizeof(struct ipsecmod_env));
75 log_err("malloc failure");
78 env->modinfo[id] = (void*)ipsecmod_env;
79 ipsecmod_env->whitelist = NULL;
80 if(!ipsecmod_apply_cfg(ipsecmod_env, env->cfg)) {
81 log_err("ipsecmod: could not apply configuration settings.");
88 ipsecmod_deinit(struct module_env* env, int id)
90 struct ipsecmod_env* ipsecmod_env;
91 if(!env || !env->modinfo[id])
93 ipsecmod_env = (struct ipsecmod_env*)env->modinfo[id];
95 ipsecmod_whitelist_delete(ipsecmod_env->whitelist);
97 env->modinfo[id] = NULL;
100 /** New query for ipsecmod. */
102 ipsecmod_new(struct module_qstate* qstate, int id)
104 struct ipsecmod_qstate* iq = (struct ipsecmod_qstate*)regional_alloc(
105 qstate->region, sizeof(struct ipsecmod_qstate));
106 qstate->minfo[id] = iq;
110 memset(iq, 0, sizeof(*iq));
111 iq->enabled = qstate->env->cfg->ipsecmod_enabled;
112 iq->is_whitelisted = ipsecmod_domain_is_whitelisted(
113 (struct ipsecmod_env*)qstate->env->modinfo[id], qstate->qinfo.qname,
114 qstate->qinfo.qname_len, qstate->qinfo.qclass);
119 * Exit module with an error status.
120 * @param qstate: query state
121 * @param id: module id.
124 ipsecmod_error(struct module_qstate* qstate, int id)
126 qstate->ext_state[id] = module_error;
127 qstate->return_rcode = LDNS_RCODE_SERVFAIL;
131 * Generate a request for the IPSECKEY.
133 * @param qstate: query state that is the parent.
134 * @param id: module id.
135 * @param name: what name to query for.
136 * @param namelen: length of name.
137 * @param qtype: query type.
138 * @param qclass: query class.
139 * @param flags: additional flags, such as the CD bit (BIT_CD), or 0.
140 * @return false on alloc failure.
143 generate_request(struct module_qstate* qstate, int id, uint8_t* name,
144 size_t namelen, uint16_t qtype, uint16_t qclass, uint16_t flags)
146 struct module_qstate* newq;
147 struct query_info ask;
149 ask.qname_len = namelen;
152 ask.local_alias = NULL;
153 log_query_info(VERB_ALGO, "ipsecmod: generate request", &ask);
154 fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub));
155 if(!(*qstate->env->attach_sub)(qstate, &ask,
156 (uint16_t)(BIT_RD|flags), 0, 0, &newq)){
157 log_err("Could not generate request: out of memory");
160 qstate->ext_state[id] = module_wait_subquery;
165 * Check if the string passed is a valid domain name with safe characters to
167 * This will only allow:
170 * - hyphen (not at the start)
171 * - dot (not at the start, or the only character)
173 * @param s: pointer to the string.
174 * @param slen: string's length.
175 * @return true if s only contains safe characters; false otherwise.
178 domainname_has_safe_characters(char* s, size_t slen) {
180 for(i = 0; i < slen; i++) {
181 if(s[i] == '\0') return 1;
182 if((s[i] == '-' && i != 0)
183 || (s[i] == '.' && (i != 0 || s[1] == '\0'))
184 || (s[i] == '_') || (s[i] >= '0' && s[i] <= '9')
185 || (s[i] >= 'A' && s[i] <= 'Z')
186 || (s[i] >= 'a' && s[i] <= 'z')) {
195 * Check if the stringified IPSECKEY RDATA contains safe characters to pass to
197 * This is only relevant for checking the gateway when the gateway type is 3
199 * @param s: pointer to the string.
200 * @param slen: string's length.
201 * @return true if s contains only safe characters; false otherwise.
204 ipseckey_has_safe_characters(char* s, size_t slen) {
205 int precedence, gateway_type, algorithm;
207 gateway = (char*)calloc(slen, sizeof(char));
209 log_err("ipsecmod: out of memory when calling the hook");
212 if(sscanf(s, "%d %d %d %s ",
213 &precedence, &gateway_type, &algorithm, gateway) != 4) {
217 if(gateway_type != 3) {
221 if(domainname_has_safe_characters(gateway, slen)) {
230 * Prepare the data and call the hook.
232 * @param qstate: query state.
233 * @param iq: ipsecmod qstate.
234 * @param ie: ipsecmod environment.
235 * @return true on success, false otherwise.
238 call_hook(struct module_qstate* qstate, struct ipsecmod_qstate* iq,
239 struct ipsecmod_env* ATTR_UNUSED(ie))
241 size_t slen, tempdata_len, tempstring_len, i;
242 char str[65535], *s, *tempstring;
243 int w = 0, w_temp, qtype;
244 struct ub_packed_rrset_key* rrset_key;
245 struct packed_rrset_data* rrset_data;
248 /* Check if a shell is available */
249 if(system(NULL) == 0) {
250 log_err("ipsecmod: no shell available for ipsecmod-hook");
254 /* Zero the buffer. */
259 /* Copy the hook into the buffer. */
260 w += sldns_str_print(&s, &slen, "%s", qstate->env->cfg->ipsecmod_hook);
261 /* Put space into the buffer. */
262 w += sldns_str_print(&s, &slen, " ");
263 /* Copy the qname into the buffer. */
264 tempstring = sldns_wire2str_dname(qstate->qinfo.qname,
265 qstate->qinfo.qname_len);
267 log_err("ipsecmod: out of memory when calling the hook");
270 if(!domainname_has_safe_characters(tempstring, strlen(tempstring))) {
271 log_err("ipsecmod: qname has unsafe characters");
275 w += sldns_str_print(&s, &slen, "\"%s\"", tempstring);
277 /* Put space into the buffer. */
278 w += sldns_str_print(&s, &slen, " ");
279 /* Copy the IPSECKEY TTL into the buffer. */
280 rrset_data = (struct packed_rrset_data*)iq->ipseckey_rrset->entry.data;
281 w += sldns_str_print(&s, &slen, "\"%ld\"", (long)rrset_data->ttl);
282 /* Put space into the buffer. */
283 w += sldns_str_print(&s, &slen, " ");
284 rrset_key = reply_find_answer_rrset(&qstate->return_msg->qinfo,
285 qstate->return_msg->rep);
286 /* Double check that the records are indeed A/AAAA.
287 * This should never happen as this function is only executed for A/AAAA
288 * queries but make sure we don't pass anything other than A/AAAA to the
290 qtype = ntohs(rrset_key->rk.type);
291 if(qtype != LDNS_RR_TYPE_AAAA && qtype != LDNS_RR_TYPE_A) {
292 log_err("ipsecmod: Answer is not of A or AAAA type");
295 rrset_data = (struct packed_rrset_data*)rrset_key->entry.data;
296 /* Copy the A/AAAA record(s) into the buffer. Start and end this section
297 * with a double quote. */
298 w += sldns_str_print(&s, &slen, "\"");
299 for(i=0; i<rrset_data->count; i++) {
301 /* Put space into the buffer. */
302 w += sldns_str_print(&s, &slen, " ");
304 /* Ignore the first two bytes, they are the rr_data len. */
305 w_temp = sldns_wire2str_rdata_buf(rrset_data->rr_data[i] + 2,
306 rrset_data->rr_len[i] - 2, s, slen, qstate->qinfo.qtype);
308 /* Error in printout. */
309 log_err("ipsecmod: Error in printing IP address");
311 } else if((size_t)w_temp >= slen) {
312 s = NULL; /* We do not want str to point outside of buffer. */
314 log_err("ipsecmod: shell command too long");
322 w += sldns_str_print(&s, &slen, "\"");
323 /* Put space into the buffer. */
324 w += sldns_str_print(&s, &slen, " ");
325 /* Copy the IPSECKEY record(s) into the buffer. Start and end this section
326 * with a double quote. */
327 w += sldns_str_print(&s, &slen, "\"");
328 rrset_data = (struct packed_rrset_data*)iq->ipseckey_rrset->entry.data;
329 for(i=0; i<rrset_data->count; i++) {
331 /* Put space into the buffer. */
332 w += sldns_str_print(&s, &slen, " ");
334 /* Ignore the first two bytes, they are the rr_data len. */
335 tempdata = rrset_data->rr_data[i] + 2;
336 tempdata_len = rrset_data->rr_len[i] - 2;
337 /* Save the buffer pointers. */
338 tempstring = s; tempstring_len = slen;
339 w_temp = sldns_wire2str_ipseckey_scan(&tempdata, &tempdata_len, &s,
340 &slen, NULL, 0, NULL);
341 /* There was an error when parsing the IPSECKEY; reset the buffer
342 * pointers to their previous values. */
344 s = tempstring; slen = tempstring_len;
345 } else if(w_temp > 0) {
346 if(!ipseckey_has_safe_characters(
347 tempstring, tempstring_len - slen)) {
348 log_err("ipsecmod: ipseckey has unsafe characters");
354 w += sldns_str_print(&s, &slen, "\"");
355 if(w >= (int)sizeof(str)) {
356 log_err("ipsecmod: shell command too long");
359 verbose(VERB_ALGO, "ipsecmod: shell command: '%s'", str);
360 /* ipsecmod-hook should return 0 on success. */
367 * Handle an ipsecmod module event with a query
368 * @param qstate: query state (from the mesh), passed between modules.
369 * contains qstate->env module environment with global caches and so on.
370 * @param iq: query state specific for this module. per-query.
371 * @param ie: environment specific for this module. global.
372 * @param id: module id.
375 ipsecmod_handle_query(struct module_qstate* qstate,
376 struct ipsecmod_qstate* iq, struct ipsecmod_env* ie, int id)
378 struct ub_packed_rrset_key* rrset_key;
379 struct packed_rrset_data* rrset_data;
381 /* Pass to next module if we are not enabled and whitelisted. */
382 if(!(iq->enabled && iq->is_whitelisted)) {
383 qstate->ext_state[id] = module_wait_module;
386 /* New query, check if the query is for an A/AAAA record and disable
387 * caching for other modules. */
388 if(!iq->ipseckey_done) {
389 if(qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
390 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) {
392 sldns_wire2str_type_buf(qstate->qinfo.qtype, type,
394 verbose(VERB_ALGO, "ipsecmod: query for %s; engaging",
396 qstate->no_cache_store = 1;
398 /* Pass request to next module. */
399 qstate->ext_state[id] = module_wait_module;
402 /* IPSECKEY subquery is finished. */
403 /* We have an IPSECKEY answer. */
404 if(iq->ipseckey_rrset) {
405 rrset_data = (struct packed_rrset_data*)iq->ipseckey_rrset->entry.data;
407 /* If bogus return SERVFAIL. */
408 if(!qstate->env->cfg->ipsecmod_ignore_bogus &&
409 rrset_data->security == sec_status_bogus) {
410 log_err("ipsecmod: bogus IPSECKEY");
411 ipsecmod_error(qstate, id);
414 /* We have a valid IPSECKEY reply, call hook. */
415 if(!call_hook(qstate, iq, ie) &&
416 qstate->env->cfg->ipsecmod_strict) {
417 log_err("ipsecmod: ipsecmod-hook failed");
418 ipsecmod_error(qstate, id);
421 /* Make sure the A/AAAA's TTL is equal/less than the
422 * ipsecmod_max_ttl. */
423 rrset_key = reply_find_answer_rrset(&qstate->return_msg->qinfo,
424 qstate->return_msg->rep);
425 rrset_data = (struct packed_rrset_data*)rrset_key->entry.data;
426 if(rrset_data->ttl > (time_t)qstate->env->cfg->ipsecmod_max_ttl) {
427 /* Update TTL for rrset to fixed value. */
428 rrset_data->ttl = qstate->env->cfg->ipsecmod_max_ttl;
429 for(i=0; i<rrset_data->count+rrset_data->rrsig_count; i++)
430 rrset_data->rr_ttl[i] = qstate->env->cfg->ipsecmod_max_ttl;
431 /* Also update reply_info's TTL */
432 if(qstate->return_msg->rep->ttl > (time_t)qstate->env->cfg->ipsecmod_max_ttl) {
433 qstate->return_msg->rep->ttl =
434 qstate->env->cfg->ipsecmod_max_ttl;
435 qstate->return_msg->rep->prefetch_ttl = PREFETCH_TTL_CALC(
436 qstate->return_msg->rep->ttl);
437 qstate->return_msg->rep->serve_expired_ttl = qstate->return_msg->rep->ttl +
438 qstate->env->cfg->serve_expired_ttl;
443 /* Store A/AAAA in cache. */
444 if(!dns_cache_store(qstate->env, &qstate->qinfo,
445 qstate->return_msg->rep, 0, qstate->prefetch_leeway,
446 0, qstate->region, qstate->query_flags)) {
447 log_err("ipsecmod: out of memory caching record");
449 qstate->ext_state[id] = module_finished;
453 * Handle an ipsecmod module event with a response from the iterator.
454 * @param qstate: query state (from the mesh), passed between modules.
455 * contains qstate->env module environment with global caches and so on.
456 * @param iq: query state specific for this module. per-query.
457 * @param ie: environment specific for this module. global.
458 * @param id: module id.
461 ipsecmod_handle_response(struct module_qstate* qstate,
462 struct ipsecmod_qstate* ATTR_UNUSED(iq),
463 struct ipsecmod_env* ATTR_UNUSED(ie), int id)
465 /* Pass to previous module if we are not enabled and whitelisted. */
466 if(!(iq->enabled && iq->is_whitelisted)) {
467 qstate->ext_state[id] = module_finished;
470 /* check if the response is for an A/AAAA query. */
471 if((qstate->qinfo.qtype == LDNS_RR_TYPE_A ||
472 qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) &&
473 /* check that we had an answer for the A/AAAA query. */
474 qstate->return_msg &&
475 reply_find_answer_rrset(&qstate->return_msg->qinfo,
476 qstate->return_msg->rep) &&
477 /* check that another module didn't SERVFAIL. */
478 qstate->return_rcode == LDNS_RCODE_NOERROR) {
480 sldns_wire2str_type_buf(qstate->qinfo.qtype, type,
482 verbose(VERB_ALGO, "ipsecmod: response for %s; generating IPSECKEY "
484 /* generate an IPSECKEY query. */
485 if(!generate_request(qstate, id, qstate->qinfo.qname,
486 qstate->qinfo.qname_len, LDNS_RR_TYPE_IPSECKEY,
487 qstate->qinfo.qclass, 0)) {
488 log_err("ipsecmod: could not generate subquery.");
489 ipsecmod_error(qstate, id);
493 /* we are done with the query. */
494 qstate->ext_state[id] = module_finished;
498 ipsecmod_operate(struct module_qstate* qstate, enum module_ev event, int id,
499 struct outbound_entry* outbound)
501 struct ipsecmod_env* ie = (struct ipsecmod_env*)qstate->env->modinfo[id];
502 struct ipsecmod_qstate* iq = (struct ipsecmod_qstate*)qstate->minfo[id];
503 verbose(VERB_QUERY, "ipsecmod[module %d] operate: extstate:%s event:%s",
504 id, strextstate(qstate->ext_state[id]), strmodulevent(event));
505 if(iq) log_query_info(VERB_QUERY, "ipsecmod operate: query",
508 /* create ipsecmod_qstate. */
509 if((event == module_event_new || event == module_event_pass) &&
511 if(!ipsecmod_new(qstate, id)) {
512 ipsecmod_error(qstate, id);
515 iq = (struct ipsecmod_qstate*)qstate->minfo[id];
517 if(iq && (event == module_event_pass || event == module_event_new)) {
518 ipsecmod_handle_query(qstate, iq, ie, id);
521 if(iq && (event == module_event_moddone)) {
522 ipsecmod_handle_response(qstate, iq, ie, id);
526 /* cachedb does not need to process responses at this time
528 cachedb_process_response(qstate, iq, ie, id, outbound, event);
532 if(event == module_event_error) {
533 verbose(VERB_ALGO, "got called with event error, giving up");
534 ipsecmod_error(qstate, id);
537 if(!iq && (event == module_event_moddone)) {
538 /* during priming, module done but we never started. */
539 qstate->ext_state[id] = module_finished;
543 log_err("ipsecmod: bad event %s", strmodulevent(event));
544 ipsecmod_error(qstate, id);
549 ipsecmod_inform_super(struct module_qstate* qstate, int id,
550 struct module_qstate* super)
552 struct ipsecmod_qstate* siq;
553 log_query_info(VERB_ALGO, "ipsecmod: inform_super, sub is",
555 log_query_info(VERB_ALGO, "super is", &super->qinfo);
556 siq = (struct ipsecmod_qstate*)super->minfo[id];
558 verbose(VERB_ALGO, "super has no ipsecmod state");
562 if(qstate->return_msg) {
563 struct ub_packed_rrset_key* rrset_key = reply_find_answer_rrset(
564 &qstate->return_msg->qinfo, qstate->return_msg->rep);
566 /* We have an answer. */
567 /* Copy to super's region. */
568 rrset_key = packed_rrset_copy_region(rrset_key, super->region, 0);
569 siq->ipseckey_rrset = rrset_key;
571 log_err("ipsecmod: out of memory.");
575 /* Notify super to proceed. */
576 siq->ipseckey_done = 1;
580 ipsecmod_clear(struct module_qstate* qstate, int id)
584 qstate->minfo[id] = NULL;
588 ipsecmod_get_mem(struct module_env* env, int id)
590 struct ipsecmod_env* ie = (struct ipsecmod_env*)env->modinfo[id];
593 return sizeof(*ie) + ipsecmod_whitelist_get_mem(ie->whitelist);
597 * The ipsecmod function block
599 static struct module_func_block ipsecmod_block = {
601 &ipsecmod_init, &ipsecmod_deinit, &ipsecmod_operate,
602 &ipsecmod_inform_super, &ipsecmod_clear, &ipsecmod_get_mem
605 struct module_func_block*
606 ipsecmod_get_funcblock(void)
608 return &ipsecmod_block;
610 #endif /* USE_IPSECMOD */