2 * iterator/iter_scrub.c - scrubbing, normalization, sanitization of DNS msgs.
4 * Copyright (c) 2007, NLnet Labs. All rights reserved.
6 * This software is open source.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 * This file has routine(s) for cleaning up incoming DNS messages from
40 * possible useless or malicious junk in it.
43 #include "iterator/iter_scrub.h"
44 #include "iterator/iterator.h"
45 #include "iterator/iter_priv.h"
46 #include "services/cache/rrset.h"
48 #include "util/net_help.h"
49 #include "util/regional.h"
50 #include "util/config_file.h"
51 #include "util/module.h"
52 #include "util/data/msgparse.h"
53 #include "util/data/dname.h"
54 #include "util/data/msgreply.h"
55 #include "util/alloc.h"
56 #include "ldns/sbuffer.h"
58 /** RRset flag used during scrubbing. The RRset is OK. */
59 #define RRSET_SCRUB_OK 0x80
61 /** remove rrset, update loop variables */
63 remove_rrset(const char* str, sldns_buffer* pkt, struct msg_parse* msg,
64 struct rrset_parse* prev, struct rrset_parse** rrset)
66 if(verbosity >= VERB_QUERY && str
67 && (*rrset)->dname_len <= LDNS_MAX_DOMAINLEN) {
68 uint8_t buf[LDNS_MAX_DOMAINLEN+1];
69 dname_pkt_copy(pkt, buf, (*rrset)->dname);
70 log_nametypeclass(VERB_QUERY, str, buf,
71 (*rrset)->type, ntohs((*rrset)->rrset_class));
74 prev->rrset_all_next = (*rrset)->rrset_all_next;
75 else msg->rrset_first = (*rrset)->rrset_all_next;
76 if(msg->rrset_last == *rrset)
77 msg->rrset_last = prev;
79 switch((*rrset)->section) {
80 case LDNS_SECTION_ANSWER: msg->an_rrsets--; break;
81 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break;
82 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break;
83 default: log_assert(0);
85 msgparse_bucket_remove(msg, *rrset);
86 *rrset = (*rrset)->rrset_all_next;
89 /** return true if rr type has additional names in it */
91 has_additional(uint16_t t)
100 case LDNS_RR_TYPE_SRV:
102 case LDNS_RR_TYPE_NAPTR:
103 /* TODO: NAPTR not supported, glue stripped off */
109 /** get additional name from rrset RR, return false if no name present */
111 get_additional_name(struct rrset_parse* rrset, struct rr_parse* rr,
112 uint8_t** nm, size_t* nmlen, sldns_buffer* pkt)
116 switch(rrset->type) {
117 case LDNS_RR_TYPE_MB:
118 case LDNS_RR_TYPE_MD:
119 case LDNS_RR_TYPE_MF:
120 case LDNS_RR_TYPE_NS:
123 case LDNS_RR_TYPE_MX:
124 case LDNS_RR_TYPE_KX:
127 case LDNS_RR_TYPE_SRV:
130 case LDNS_RR_TYPE_NAPTR:
131 /* TODO: NAPTR not supported, glue stripped off */
136 len = sldns_read_uint16(rr->ttl_data+sizeof(uint32_t));
138 return 0; /* rdata field too small */
139 *nm = rr->ttl_data+sizeof(uint32_t)+sizeof(uint16_t)+offset;
140 oldpos = sldns_buffer_position(pkt);
141 sldns_buffer_set_position(pkt, (size_t)(*nm - sldns_buffer_begin(pkt)));
142 *nmlen = pkt_dname_len(pkt);
143 sldns_buffer_set_position(pkt, oldpos);
149 /** Place mark on rrsets in additional section they are OK */
151 mark_additional_rrset(sldns_buffer* pkt, struct msg_parse* msg,
152 struct rrset_parse* rrset)
154 /* Mark A and AAAA for NS as appropriate additional section info. */
159 if(!has_additional(rrset->type))
161 for(rr = rrset->rr_first; rr; rr = rr->next) {
162 if(get_additional_name(rrset, rr, &nm, &nmlen, pkt)) {
164 hashvalue_t h = pkt_hash_rrset(pkt, nm, LDNS_RR_TYPE_A,
165 rrset->rrset_class, 0);
166 struct rrset_parse* r = msgparse_hashtable_lookup(
167 msg, pkt, h, 0, nm, nmlen,
168 LDNS_RR_TYPE_A, rrset->rrset_class);
169 if(r && r->section == LDNS_SECTION_ADDITIONAL) {
170 r->flags |= RRSET_SCRUB_OK;
174 h = pkt_hash_rrset(pkt, nm, LDNS_RR_TYPE_AAAA,
175 rrset->rrset_class, 0);
176 r = msgparse_hashtable_lookup(msg, pkt, h, 0, nm,
177 nmlen, LDNS_RR_TYPE_AAAA, rrset->rrset_class);
178 if(r && r->section == LDNS_SECTION_ADDITIONAL) {
179 r->flags |= RRSET_SCRUB_OK;
185 /** Get target name of a CNAME */
187 parse_get_cname_target(struct rrset_parse* rrset, uint8_t** sname,
190 if(rrset->rr_count != 1) {
191 struct rr_parse* sig;
192 verbose(VERB_ALGO, "Found CNAME rrset with "
193 "size > 1: %u", (unsigned)rrset->rr_count);
194 /* use the first CNAME! */
196 rrset->size = rrset->rr_first->size;
197 for(sig=rrset->rrsig_first; sig; sig=sig->next)
198 rrset->size += sig->size;
199 rrset->rr_last = rrset->rr_first;
200 rrset->rr_first->next = NULL;
202 if(rrset->rr_first->size < sizeof(uint16_t)+1)
203 return 0; /* CNAME rdata too small */
204 *sname = rrset->rr_first->ttl_data + sizeof(uint32_t)
205 + sizeof(uint16_t); /* skip ttl, rdatalen */
206 *snamelen = rrset->rr_first->size - sizeof(uint16_t);
210 /** Synthesize CNAME from DNAME, false if too long */
212 synth_cname(uint8_t* qname, size_t qnamelen, struct rrset_parse* dname_rrset,
213 uint8_t* alias, size_t* aliaslen, sldns_buffer* pkt)
215 /* we already know that sname is a strict subdomain of DNAME owner */
216 uint8_t* dtarg = NULL;
218 if(!parse_get_cname_target(dname_rrset, &dtarg, &dtarglen))
220 log_assert(qnamelen > dname_rrset->dname_len);
221 /* DNAME from com. to net. with qname example.com. -> example.net. */
222 /* so: \3com\0 to \3net\0 and qname \7example\3com\0 */
223 *aliaslen = qnamelen + dtarglen - dname_rrset->dname_len;
224 if(*aliaslen > LDNS_MAX_DOMAINLEN)
225 return 0; /* should have been RCODE YXDOMAIN */
226 /* decompress dnames into buffer, we know it fits */
227 dname_pkt_copy(pkt, alias, qname);
228 dname_pkt_copy(pkt, alias+(qnamelen-dname_rrset->dname_len), dtarg);
232 /** synthesize a CNAME rrset */
233 static struct rrset_parse*
234 synth_cname_rrset(uint8_t** sname, size_t* snamelen, uint8_t* alias,
235 size_t aliaslen, struct regional* region, struct msg_parse* msg,
236 struct rrset_parse* rrset, struct rrset_parse* prev,
237 struct rrset_parse* nx, sldns_buffer* pkt)
239 struct rrset_parse* cn = (struct rrset_parse*)regional_alloc(region,
240 sizeof(struct rrset_parse));
243 memset(cn, 0, sizeof(*cn));
244 cn->rr_first = (struct rr_parse*)regional_alloc(region,
245 sizeof(struct rr_parse));
248 cn->rr_last = cn->rr_first;
249 /* CNAME from sname to alias */
250 cn->dname = (uint8_t*)regional_alloc(region, *snamelen);
253 dname_pkt_copy(pkt, cn->dname, *sname);
254 cn->dname_len = *snamelen;
255 cn->type = LDNS_RR_TYPE_CNAME;
256 cn->section = rrset->section;
257 cn->rrset_class = rrset->rrset_class;
259 cn->size = sizeof(uint16_t) + aliaslen;
260 cn->hash=pkt_hash_rrset(pkt, cn->dname, cn->type, cn->rrset_class, 0);
261 /* allocate TTL + rdatalen + uncompressed dname */
262 memset(cn->rr_first, 0, sizeof(struct rr_parse));
263 cn->rr_first->outside_packet = 1;
264 cn->rr_first->ttl_data = (uint8_t*)regional_alloc(region,
265 sizeof(uint32_t)+sizeof(uint16_t)+aliaslen);
266 if(!cn->rr_first->ttl_data)
268 sldns_write_uint32(cn->rr_first->ttl_data, 0); /* TTL = 0 */
269 sldns_write_uint16(cn->rr_first->ttl_data+4, aliaslen);
270 memmove(cn->rr_first->ttl_data+6, alias, aliaslen);
271 cn->rr_first->size = sizeof(uint16_t)+aliaslen;
274 cn->rrset_all_next = nx;
276 prev->rrset_all_next = cn;
277 else msg->rrset_first = cn;
279 msg->rrset_last = cn;
282 /* it is not inserted in the msg hashtable. */
284 *sname = cn->rr_first->ttl_data + sizeof(uint32_t)+sizeof(uint16_t);
285 *snamelen = aliaslen;
289 /** check if DNAME applies to a name */
291 pkt_strict_sub(sldns_buffer* pkt, uint8_t* sname, uint8_t* dr)
293 uint8_t buf1[LDNS_MAX_DOMAINLEN+1];
294 uint8_t buf2[LDNS_MAX_DOMAINLEN+1];
295 /* decompress names */
296 dname_pkt_copy(pkt, buf1, sname);
297 dname_pkt_copy(pkt, buf2, dr);
298 return dname_strict_subdomain_c(buf1, buf2);
301 /** check subdomain with decompression */
303 pkt_sub(sldns_buffer* pkt, uint8_t* comprname, uint8_t* zone)
305 uint8_t buf[LDNS_MAX_DOMAINLEN+1];
306 dname_pkt_copy(pkt, buf, comprname);
307 return dname_subdomain_c(buf, zone);
310 /** check subdomain with decompression, compressed is parent */
312 sub_of_pkt(sldns_buffer* pkt, uint8_t* zone, uint8_t* comprname)
314 uint8_t buf[LDNS_MAX_DOMAINLEN+1];
315 dname_pkt_copy(pkt, buf, comprname);
316 return dname_subdomain_c(zone, buf);
320 * This routine normalizes a response. This includes removing "irrelevant"
321 * records from the answer and additional sections and (re)synthesizing
322 * CNAMEs from DNAMEs, if present.
324 * @param pkt: packet.
325 * @param msg: msg to normalize.
326 * @param qinfo: original query.
327 * @param region: where to allocate synthesized CNAMEs.
328 * @return 0 on error.
331 scrub_normalize(sldns_buffer* pkt, struct msg_parse* msg,
332 struct query_info* qinfo, struct regional* region)
334 uint8_t* sname = qinfo->qname;
335 size_t snamelen = qinfo->qname_len;
336 struct rrset_parse* rrset, *prev, *nsset=NULL;
338 if(FLAGS_GET_RCODE(msg->flags) != LDNS_RCODE_NOERROR &&
339 FLAGS_GET_RCODE(msg->flags) != LDNS_RCODE_NXDOMAIN)
342 /* For the ANSWER section, remove all "irrelevant" records and add
343 * synthesized CNAMEs from DNAMEs
344 * This will strip out-of-order CNAMEs as well. */
346 /* walk through the parse packet rrset list, keep track of previous
347 * for insert and delete ease, and examine every RRset */
349 rrset = msg->rrset_first;
350 while(rrset && rrset->section == LDNS_SECTION_ANSWER) {
351 if(rrset->type == LDNS_RR_TYPE_DNAME &&
352 pkt_strict_sub(pkt, sname, rrset->dname)) {
353 /* check if next rrset is correct CNAME. else,
354 * synthesize a CNAME */
355 struct rrset_parse* nx = rrset->rrset_all_next;
356 uint8_t alias[LDNS_MAX_DOMAINLEN+1];
358 if(rrset->rr_count != 1) {
359 verbose(VERB_ALGO, "Found DNAME rrset with "
361 (unsigned)rrset->rr_count);
364 if(!synth_cname(sname, snamelen, rrset, alias,
366 verbose(VERB_ALGO, "synthesized CNAME "
370 if(nx && nx->type == LDNS_RR_TYPE_CNAME &&
371 dname_pkt_compare(pkt, sname, nx->dname) == 0) {
372 /* check next cname */
375 if(!parse_get_cname_target(rrset, &t, &tlen))
377 if(dname_pkt_compare(pkt, alias, t) == 0) {
378 /* it's OK and better capitalized */
383 /* synth ourselves */
385 /* synth a CNAME rrset */
386 prev = synth_cname_rrset(&sname, &snamelen, alias,
387 aliaslen, region, msg, rrset, rrset, nx, pkt);
389 log_err("out of memory synthesizing CNAME");
392 /* FIXME: resolve the conflict between synthesized
393 * CNAME ttls and the cache. */
399 /* The only records in the ANSWER section not allowed to */
400 if(dname_pkt_compare(pkt, sname, rrset->dname) != 0) {
401 remove_rrset("normalize: removing irrelevant RRset:",
402 pkt, msg, prev, &rrset);
406 /* Follow the CNAME chain. */
407 if(rrset->type == LDNS_RR_TYPE_CNAME) {
408 uint8_t* oldsname = sname;
409 if(!parse_get_cname_target(rrset, &sname, &snamelen))
412 rrset = rrset->rrset_all_next;
413 /* in CNAME ANY response, can have data after CNAME */
414 if(qinfo->qtype == LDNS_RR_TYPE_ANY) {
415 while(rrset && rrset->section ==
416 LDNS_SECTION_ANSWER &&
417 dname_pkt_compare(pkt, oldsname,
418 rrset->dname) == 0) {
420 rrset = rrset->rrset_all_next;
426 /* Otherwise, make sure that the RRset matches the qtype. */
427 if(qinfo->qtype != LDNS_RR_TYPE_ANY &&
428 qinfo->qtype != rrset->type) {
429 remove_rrset("normalize: removing irrelevant RRset:",
430 pkt, msg, prev, &rrset);
434 /* Mark the additional names from relevant rrset as OK. */
435 /* only for RRsets that match the query name, other ones
436 * will be removed by sanitize, so no additional for them */
437 if(dname_pkt_compare(pkt, qinfo->qname, rrset->dname) == 0)
438 mark_additional_rrset(pkt, msg, rrset);
441 rrset = rrset->rrset_all_next;
444 /* Mark additional names from AUTHORITY */
445 while(rrset && rrset->section == LDNS_SECTION_AUTHORITY) {
446 if(rrset->type==LDNS_RR_TYPE_DNAME ||
447 rrset->type==LDNS_RR_TYPE_CNAME ||
448 rrset->type==LDNS_RR_TYPE_A ||
449 rrset->type==LDNS_RR_TYPE_AAAA) {
450 remove_rrset("normalize: removing irrelevant "
451 "RRset:", pkt, msg, prev, &rrset);
454 /* only one NS set allowed in authority section */
455 if(rrset->type==LDNS_RR_TYPE_NS) {
456 /* NS set must be pertinent to the query */
457 if(!sub_of_pkt(pkt, qinfo->qname, rrset->dname)) {
458 remove_rrset("normalize: removing irrelevant "
459 "RRset:", pkt, msg, prev, &rrset);
465 remove_rrset("normalize: removing irrelevant "
466 "RRset:", pkt, msg, prev, &rrset);
470 mark_additional_rrset(pkt, msg, rrset);
472 rrset = rrset->rrset_all_next;
475 /* For each record in the additional section, remove it if it is an
476 * address record and not in the collection of additional names
477 * found in ANSWER and AUTHORITY. */
478 /* These records have not been marked OK previously */
479 while(rrset && rrset->section == LDNS_SECTION_ADDITIONAL) {
480 /* FIXME: what about other types? */
481 if(rrset->type==LDNS_RR_TYPE_A ||
482 rrset->type==LDNS_RR_TYPE_AAAA)
484 if((rrset->flags & RRSET_SCRUB_OK)) {
485 /* remove flag to clean up flags variable */
486 rrset->flags &= ~RRSET_SCRUB_OK;
488 remove_rrset("normalize: removing irrelevant "
489 "RRset:", pkt, msg, prev, &rrset);
493 if(rrset->type==LDNS_RR_TYPE_DNAME ||
494 rrset->type==LDNS_RR_TYPE_CNAME ||
495 rrset->type==LDNS_RR_TYPE_NS) {
496 remove_rrset("normalize: removing irrelevant "
497 "RRset:", pkt, msg, prev, &rrset);
501 rrset = rrset->rrset_all_next;
508 * Store potential poison in the cache (only if hardening disabled).
509 * The rrset is stored in the cache but removed from the message.
510 * So that it will be used for infrastructure purposes, but not be
511 * returned to the client.
513 * @param msg: message parsed
514 * @param env: environment with cache
515 * @param rrset: to store.
518 store_rrset(sldns_buffer* pkt, struct msg_parse* msg, struct module_env* env,
519 struct rrset_parse* rrset)
521 struct ub_packed_rrset_key* k;
522 struct packed_rrset_data* d;
523 struct rrset_ref ref;
524 time_t now = *env->now;
526 k = alloc_special_obtain(env->alloc);
529 k->entry.data = NULL;
530 if(!parse_copy_decompress_rrset(pkt, msg, rrset, NULL, k)) {
531 alloc_special_release(env->alloc, k);
534 d = (struct packed_rrset_data*)k->entry.data;
535 packed_rrset_ttl_add(d, now);
538 /*ignore ret: it was in the cache, ref updated */
539 (void)rrset_cache_update(env->rrset_cache, &ref, env->alloc, now);
542 /** Check if there are SOA records in the authority section (negative) */
544 soa_in_auth(struct msg_parse* msg)
546 struct rrset_parse* rrset;
547 for(rrset = msg->rrset_first; rrset; rrset = rrset->rrset_all_next)
548 if(rrset->type == LDNS_RR_TYPE_SOA &&
549 rrset->section == LDNS_SECTION_AUTHORITY)
555 * Check if right hand name in NSEC is within zone
556 * @param rrset: the NSEC rrset
557 * @param zonename: the zone name.
558 * @return true if BAD.
560 static int sanitize_nsec_is_overreach(struct rrset_parse* rrset,
566 log_assert(rrset->type == LDNS_RR_TYPE_NSEC);
567 for(rr = rrset->rr_first; rr; rr = rr->next) {
568 rhs = rr->ttl_data+4+2;
569 len = sldns_read_uint16(rr->ttl_data+4);
570 if(!dname_valid(rhs, len)) {
571 /* malformed domain name in rdata */
574 if(!dname_subdomain_c(rhs, zonename)) {
579 /* all NSEC RRs OK */
584 * Given a response event, remove suspect RRsets from the response.
585 * "Suspect" rrsets are potentially poison. Note that this routine expects
586 * the response to be in a "normalized" state -- that is, all "irrelevant"
587 * RRsets have already been removed, CNAMEs are in order, etc.
589 * @param pkt: packet.
590 * @param msg: msg to normalize.
591 * @param qinfo: the question originally asked.
592 * @param zonename: name of server zone.
593 * @param env: module environment with config and cache.
594 * @param ie: iterator environment with private address data.
595 * @return 0 on error.
598 scrub_sanitize(sldns_buffer* pkt, struct msg_parse* msg,
599 struct query_info* qinfo, uint8_t* zonename, struct module_env* env,
602 int del_addi = 0; /* if additional-holding rrsets are deleted, we
603 do not trust the normalized additional-A-AAAA any more */
604 struct rrset_parse* rrset, *prev;
606 rrset = msg->rrset_first;
608 /* the first DNAME is allowed to stay. It needs checking before
609 * it can be used from the cache. After normalization, an initial
610 * DNAME will have a correctly synthesized CNAME after it. */
611 if(rrset && rrset->type == LDNS_RR_TYPE_DNAME &&
612 rrset->section == LDNS_SECTION_ANSWER &&
613 pkt_strict_sub(pkt, qinfo->qname, rrset->dname) &&
614 pkt_sub(pkt, rrset->dname, zonename)) {
615 prev = rrset; /* DNAME allowed to stay in answer section */
616 rrset = rrset->rrset_all_next;
619 /* remove all records from the answer section that are
620 * not the same domain name as the query domain name.
621 * The answer section should contain rrsets with the same name
622 * as the question. For DNAMEs a CNAME has been synthesized.
623 * Wildcards have the query name in answer section.
624 * ANY queries get query name in answer section.
625 * Remainders of CNAME chains are cut off and resolved by iterator. */
626 while(rrset && rrset->section == LDNS_SECTION_ANSWER) {
627 if(dname_pkt_compare(pkt, qinfo->qname, rrset->dname) != 0) {
628 if(has_additional(rrset->type)) del_addi = 1;
629 remove_rrset("sanitize: removing extraneous answer "
630 "RRset:", pkt, msg, prev, &rrset);
634 rrset = rrset->rrset_all_next;
637 /* At this point, we brutally remove ALL rrsets that aren't
638 * children of the originating zone. The idea here is that,
639 * as far as we know, the server that we contacted is ONLY
640 * authoritative for the originating zone. It, of course, MAY
641 * be authoriative for any other zones, and of course, MAY
642 * NOT be authoritative for some subdomains of the originating
645 rrset = msg->rrset_first;
648 /* remove private addresses */
649 if( (rrset->type == LDNS_RR_TYPE_A ||
650 rrset->type == LDNS_RR_TYPE_AAAA)) {
652 /* do not set servfail since this leads to too
653 * many drops of other people using rfc1918 space */
654 /* also do not remove entire rrset, unless all records
656 if(priv_rrset_bad(ie->priv, pkt, rrset)) {
657 remove_rrset(NULL, pkt, msg, prev, &rrset);
662 /* skip DNAME records -- they will always be followed by a
663 * synthesized CNAME, which will be relevant.
664 * FIXME: should this do something differently with DNAME
665 * rrsets NOT in Section.ANSWER? */
666 /* But since DNAME records are also subdomains of the zone,
667 * same check can be used */
669 if(!pkt_sub(pkt, rrset->dname, zonename)) {
670 if(msg->an_rrsets == 0 &&
671 rrset->type == LDNS_RR_TYPE_NS &&
672 rrset->section == LDNS_SECTION_AUTHORITY &&
673 FLAGS_GET_RCODE(msg->flags) ==
674 LDNS_RCODE_NOERROR && !soa_in_auth(msg) &&
675 sub_of_pkt(pkt, zonename, rrset->dname)) {
676 /* noerror, nodata and this NS rrset is above
677 * the zone. This is LAME!
678 * Leave in the NS for lame classification. */
679 /* remove everything from the additional
680 * (we dont want its glue that was approved
681 * during the normalize action) */
683 } else if(!env->cfg->harden_glue) {
684 /* store in cache! Since it is relevant
685 * (from normalize) it will be picked up
686 * from the cache to be used later */
687 store_rrset(pkt, msg, env, rrset);
688 remove_rrset("sanitize: storing potential "
689 "poison RRset:", pkt, msg, prev, &rrset);
692 if(has_additional(rrset->type)) del_addi = 1;
693 remove_rrset("sanitize: removing potential "
694 "poison RRset:", pkt, msg, prev, &rrset);
698 if(del_addi && rrset->section == LDNS_SECTION_ADDITIONAL) {
699 remove_rrset("sanitize: removing potential "
700 "poison reference RRset:", pkt, msg, prev, &rrset);
703 /* check if right hand side of NSEC is within zone */
704 if(rrset->type == LDNS_RR_TYPE_NSEC &&
705 sanitize_nsec_is_overreach(rrset, zonename)) {
706 remove_rrset("sanitize: removing overreaching NSEC "
707 "RRset:", pkt, msg, prev, &rrset);
711 rrset = rrset->rrset_all_next;
717 scrub_message(sldns_buffer* pkt, struct msg_parse* msg,
718 struct query_info* qinfo, uint8_t* zonename, struct regional* region,
719 struct module_env* env, struct iter_env* ie)
721 /* basic sanity checks */
722 log_nametypeclass(VERB_ALGO, "scrub for", zonename, LDNS_RR_TYPE_NS,
726 if( !(msg->flags&BIT_QR) )
728 msg->flags &= ~(BIT_AD|BIT_Z); /* force off bit AD and Z */
730 /* make sure that a query is echoed back when NOERROR or NXDOMAIN */
731 /* this is not required for basic operation but is a forgery
732 * resistance (security) feature */
733 if((FLAGS_GET_RCODE(msg->flags) == LDNS_RCODE_NOERROR ||
734 FLAGS_GET_RCODE(msg->flags) == LDNS_RCODE_NXDOMAIN) &&
738 /* if a query is echoed back, make sure it is correct. Otherwise,
739 * this may be not a reply to our query. */
740 if(msg->qdcount == 1) {
741 if(dname_pkt_compare(pkt, msg->qname, qinfo->qname) != 0)
743 if(msg->qtype != qinfo->qtype || msg->qclass != qinfo->qclass)
747 /* normalize the response, this cleans up the additional. */
748 if(!scrub_normalize(pkt, msg, qinfo, region))
750 /* delete all out-of-zone information */
751 if(!scrub_sanitize(pkt, msg, qinfo, zonename, env, ie))