1/* 2 * util/data/msgparse.c - parse wireformat DNS messages. 3 * 4 * Copyright (c) 2007, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 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. 18 * 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. 22 * 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. 34 */ 35/** 36 * \file 37 * Routines for message parsing a packet buffer to a descriptive structure. 38 */ 39#include "config.h" 40#include "util/config_file.h" 41#include "util/data/msgparse.h" 42#include "util/data/msgreply.h" 43#include "util/data/dname.h" 44#include "util/data/packed_rrset.h" 45#include "util/netevent.h" 46#include "util/storage/lookup3.h" 47#include "util/regional.h" 48#include "util/rfc_1982.h" 49#include "util/edns.h" 50#include "util/net_help.h" 51#include "sldns/rrdef.h" 52#include "sldns/sbuffer.h" 53#include "sldns/parseutil.h" 54#include "sldns/wire2str.h" 55 56/** smart comparison of (compressed, valid) dnames from packet */ 57static int 58smart_compare(sldns_buffer* pkt, uint8_t* dnow, 59 uint8_t* dprfirst, uint8_t* dprlast) 60{ 61 if(LABEL_IS_PTR(*dnow)) { 62 /* ptr points to a previous dname */ 63 uint8_t* p; 64 if((size_t)PTR_OFFSET(dnow[0], dnow[1]) 65 >= sldns_buffer_limit(pkt)) 66 return -1; 67 p = sldns_buffer_at(pkt, PTR_OFFSET(dnow[0], dnow[1])); 68 if( p == dprfirst || p == dprlast ) 69 return 0; 70 /* prev dname is also a ptr, both ptrs are the same. */ 71 if(LABEL_IS_PTR(*dprlast) && 72 dprlast[0] == dnow[0] && dprlast[1] == dnow[1]) 73 return 0; 74 } 75 return dname_pkt_compare(pkt, dnow, dprlast); 76} 77 78/** 79 * Allocate new rrset in region, fill with data. 80 */ 81static struct rrset_parse* 82new_rrset(struct msg_parse* msg, uint8_t* dname, size_t dnamelen, 83 uint16_t type, uint16_t dclass, hashvalue_type hash, 84 uint32_t rrset_flags, sldns_pkt_section section, 85 struct regional* region) 86{ 87 struct rrset_parse* p = regional_alloc(region, sizeof(*p)); 88 if(!p) return NULL; 89 p->rrset_bucket_next = msg->hashtable[hash & (PARSE_TABLE_SIZE-1)]; 90 msg->hashtable[hash & (PARSE_TABLE_SIZE-1)] = p; 91 p->rrset_all_next = 0; 92 if(msg->rrset_last) 93 msg->rrset_last->rrset_all_next = p; 94 else msg->rrset_first = p; 95 msg->rrset_last = p; 96 p->hash = hash; 97 p->section = section; 98 p->dname = dname; 99 p->dname_len = dnamelen; 100 p->type = type; 101 p->rrset_class = dclass; 102 p->flags = rrset_flags; 103 p->rr_count = 0; 104 p->size = 0; 105 p->rr_first = 0; 106 p->rr_last = 0; 107 p->rrsig_count = 0; 108 p->rrsig_first = 0; 109 p->rrsig_last = 0; 110 return p; 111} 112 113/** See if next rrset is nsec at zone apex */ 114static int 115nsec_at_apex(sldns_buffer* pkt) 116{ 117 /* we are at ttl position in packet. */ 118 size_t pos = sldns_buffer_position(pkt); 119 uint16_t rdatalen; 120 if(sldns_buffer_remaining(pkt) < 7) /* ttl+len+root */ 121 return 0; /* eek! */ 122 sldns_buffer_skip(pkt, 4); /* ttl */; 123 rdatalen = sldns_buffer_read_u16(pkt); 124 if(sldns_buffer_remaining(pkt) < rdatalen) { 125 sldns_buffer_set_position(pkt, pos); 126 return 0; /* parse error happens later */ 127 } 128 /* must validate the nsec next domain name format */ 129 if(pkt_dname_len(pkt) == 0) { 130 sldns_buffer_set_position(pkt, pos); 131 return 0; /* parse error */ 132 } 133 134 /* see if SOA bit is set. */ 135 if(sldns_buffer_position(pkt) < pos+4+rdatalen) { 136 /* nsec type bitmap contains items */ 137 uint8_t win, blen, bits; 138 /* need: windownum, bitmap len, firstbyte */ 139 if(sldns_buffer_position(pkt)+3 > pos+4+rdatalen) { 140 sldns_buffer_set_position(pkt, pos); 141 return 0; /* malformed nsec */ 142 } 143 win = sldns_buffer_read_u8(pkt); 144 blen = sldns_buffer_read_u8(pkt); 145 bits = sldns_buffer_read_u8(pkt); 146 /* 0window always first window. bitlen >=1 or parse 147 error really. bit 0x2 is SOA. */ 148 if(win == 0 && blen >= 1 && (bits & 0x02)) { 149 sldns_buffer_set_position(pkt, pos); 150 return 1; 151 } 152 } 153 154 sldns_buffer_set_position(pkt, pos); 155 return 0; 156} 157 158/** Calculate rrset flags */ 159static uint32_t 160pkt_rrset_flags(sldns_buffer* pkt, uint16_t type, sldns_pkt_section sec) 161{ 162 uint32_t f = 0; 163 if(type == LDNS_RR_TYPE_NSEC && nsec_at_apex(pkt)) { 164 f |= PACKED_RRSET_NSEC_AT_APEX; 165 } else if(type == LDNS_RR_TYPE_SOA && sec == LDNS_SECTION_AUTHORITY) { 166 f |= PACKED_RRSET_SOA_NEG; 167 } 168 return f; 169} 170 171hashvalue_type 172pkt_hash_rrset(sldns_buffer* pkt, uint8_t* dname, uint16_t type, 173 uint16_t dclass, uint32_t rrset_flags) 174{ 175 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 176 /* this routine handles compressed names */ 177 hashvalue_type h = 0xab; 178 h = dname_pkt_hash(pkt, dname, h); 179 h = hashlittle(&type, sizeof(type), h); /* host order */ 180 h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ 181 h = hashlittle(&rrset_flags, sizeof(uint32_t), h); 182 return h; 183} 184 185/** create partial dname hash for rrset hash */ 186static hashvalue_type 187pkt_hash_rrset_first(sldns_buffer* pkt, uint8_t* dname) 188{ 189 /* works together with pkt_hash_rrset_rest */ 190 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 191 /* this routine handles compressed names */ 192 hashvalue_type h = 0xab; 193 h = dname_pkt_hash(pkt, dname, h); 194 return h; 195} 196 197/** create a rrset hash from a partial dname hash */ 198static hashvalue_type 199pkt_hash_rrset_rest(hashvalue_type dname_h, uint16_t type, uint16_t dclass, 200 uint32_t rrset_flags) 201{ 202 /* works together with pkt_hash_rrset_first */ 203 /* note this MUST be identical to rrset_key_hash in packed_rrset.c */ 204 hashvalue_type h; 205 h = hashlittle(&type, sizeof(type), dname_h); /* host order */ 206 h = hashlittle(&dclass, sizeof(dclass), h); /* netw order */ 207 h = hashlittle(&rrset_flags, sizeof(uint32_t), h); 208 return h; 209} 210 211/** compare rrset_parse with data */ 212static int 213rrset_parse_equals(struct rrset_parse* p, sldns_buffer* pkt, hashvalue_type h, 214 uint32_t rrset_flags, uint8_t* dname, size_t dnamelen, 215 uint16_t type, uint16_t dclass) 216{ 217 if(p->hash == h && p->dname_len == dnamelen && p->type == type && 218 p->rrset_class == dclass && p->flags == rrset_flags && 219 dname_pkt_compare(pkt, dname, p->dname) == 0) 220 return 1; 221 return 0; 222} 223 224 225struct rrset_parse* 226msgparse_hashtable_lookup(struct msg_parse* msg, sldns_buffer* pkt, 227 hashvalue_type h, uint32_t rrset_flags, uint8_t* dname, 228 size_t dnamelen, uint16_t type, uint16_t dclass) 229{ 230 struct rrset_parse* p = msg->hashtable[h & (PARSE_TABLE_SIZE-1)]; 231 while(p) { 232 if(rrset_parse_equals(p, pkt, h, rrset_flags, dname, dnamelen, 233 type, dclass)) 234 return p; 235 p = p->rrset_bucket_next; 236 } 237 return NULL; 238} 239 240/** return type networkformat that rrsig in packet covers */ 241static int 242pkt_rrsig_covered(sldns_buffer* pkt, uint8_t* here, uint16_t* type) 243{ 244 size_t pos = sldns_buffer_position(pkt); 245 sldns_buffer_set_position(pkt, (size_t)(here-sldns_buffer_begin(pkt))); 246 /* ttl + len + size of small rrsig(rootlabel, no signature) */ 247 if(sldns_buffer_remaining(pkt) < 4+2+19) 248 return 0; 249 sldns_buffer_skip(pkt, 4); /* ttl */ 250 if(sldns_buffer_read_u16(pkt) < 19) /* too short */ { 251 sldns_buffer_set_position(pkt, pos); 252 return 0; 253 } 254 *type = sldns_buffer_read_u16(pkt); 255 sldns_buffer_set_position(pkt, pos); 256 return 1; 257} 258 259/** true if covered type equals prevtype */ 260static int 261pkt_rrsig_covered_equals(sldns_buffer* pkt, uint8_t* here, uint16_t type) 262{ 263 uint16_t t; 264 if(pkt_rrsig_covered(pkt, here, &t) && t == type) 265 return 1; 266 return 0; 267} 268 269void 270msgparse_bucket_remove(struct msg_parse* msg, struct rrset_parse* rrset) 271{ 272 struct rrset_parse** p; 273 p = &msg->hashtable[ rrset->hash & (PARSE_TABLE_SIZE-1) ]; 274 while(*p) { 275 if(*p == rrset) { 276 *p = rrset->rrset_bucket_next; 277 return; 278 } 279 p = &( (*p)->rrset_bucket_next ); 280 } 281} 282 283/** change section of rrset from previous to current section */ 284static void 285change_section(struct msg_parse* msg, struct rrset_parse* rrset, 286 sldns_pkt_section section) 287{ 288 struct rrset_parse *p, *prev; 289 /* remove from list */ 290 if(section == rrset->section) 291 return; 292 p = msg->rrset_first; 293 prev = 0; 294 while(p) { 295 if(p == rrset) { 296 if(prev) prev->rrset_all_next = p->rrset_all_next; 297 else msg->rrset_first = p->rrset_all_next; 298 if(msg->rrset_last == rrset) 299 msg->rrset_last = prev; 300 break; 301 } 302 prev = p; 303 p = p->rrset_all_next; 304 } 305 /* remove from count */ 306 switch(rrset->section) { 307 case LDNS_SECTION_ANSWER: msg->an_rrsets--; break; 308 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets--; break; 309 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets--; break; 310 default: log_assert(0); 311 } 312 /* insert at end of list */ 313 rrset->rrset_all_next = 0; 314 if(msg->rrset_last) 315 msg->rrset_last->rrset_all_next = rrset; 316 else msg->rrset_first = rrset; 317 msg->rrset_last = rrset; 318 /* up count of new section */ 319 switch(section) { 320 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; 321 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; 322 default: log_assert(0); 323 } 324 rrset->section = section; 325} 326 327/** see if rrset of type RRSIG contains sig over given type */ 328static int 329rrset_has_sigover(sldns_buffer* pkt, struct rrset_parse* rrset, uint16_t type, 330 int* hasother) 331{ 332 int res = 0; 333 struct rr_parse* rr = rrset->rr_first; 334 log_assert( rrset->type == LDNS_RR_TYPE_RRSIG ); 335 while(rr) { 336 if(pkt_rrsig_covered_equals(pkt, rr->ttl_data, type)) 337 res = 1; 338 else *hasother = 1; 339 rr = rr->next; 340 } 341 return res; 342} 343 344/** move rrsigs from sigset to dataset */ 345static int 346moveover_rrsigs(sldns_buffer* pkt, struct regional* region, 347 struct rrset_parse* sigset, struct rrset_parse* dataset, int duplicate) 348{ 349 struct rr_parse* sig = sigset->rr_first; 350 struct rr_parse* prev = NULL; 351 struct rr_parse* insert; 352 struct rr_parse* nextsig; 353 while(sig) { 354 nextsig = sig->next; 355 if(pkt_rrsig_covered_equals(pkt, sig->ttl_data, 356 dataset->type)) { 357 if(duplicate) { 358 /* new */ 359 insert = (struct rr_parse*)regional_alloc( 360 region, sizeof(struct rr_parse)); 361 if(!insert) return 0; 362 insert->outside_packet = 0; 363 insert->ttl_data = sig->ttl_data; 364 insert->size = sig->size; 365 /* prev not used */ 366 } else { 367 /* remove from sigset */ 368 if(prev) prev->next = sig->next; 369 else sigset->rr_first = sig->next; 370 if(sigset->rr_last == sig) 371 sigset->rr_last = prev; 372 sigset->rr_count--; 373 sigset->size -= sig->size; 374 insert = sig; 375 /* prev not changed */ 376 } 377 /* add to dataset */ 378 dataset->rrsig_count++; 379 insert->next = 0; 380 if(dataset->rrsig_last) 381 dataset->rrsig_last->next = insert; 382 else dataset->rrsig_first = insert; 383 dataset->rrsig_last = insert; 384 dataset->size += insert->size; 385 } else { 386 prev = sig; 387 } 388 sig = nextsig; 389 } 390 return 1; 391} 392 393/** change an rrsig rrset for use as data rrset */ 394static struct rrset_parse* 395change_rrsig_rrset(struct rrset_parse* sigset, struct msg_parse* msg, 396 sldns_buffer* pkt, uint16_t datatype, uint32_t rrset_flags, 397 int hasother, sldns_pkt_section section, struct regional* region) 398{ 399 struct rrset_parse* dataset = sigset; 400 hashvalue_type hash = pkt_hash_rrset(pkt, sigset->dname, datatype, 401 sigset->rrset_class, rrset_flags); 402 log_assert( sigset->type == LDNS_RR_TYPE_RRSIG ); 403 log_assert( datatype != LDNS_RR_TYPE_RRSIG ); 404 if(hasother) { 405 /* need to make new rrset to hold data type */ 406 dataset = new_rrset(msg, sigset->dname, sigset->dname_len, 407 datatype, sigset->rrset_class, hash, rrset_flags, 408 section, region); 409 if(!dataset) 410 return NULL; 411 switch(section) { 412 case LDNS_SECTION_ANSWER: msg->an_rrsets++; break; 413 case LDNS_SECTION_AUTHORITY: msg->ns_rrsets++; break; 414 case LDNS_SECTION_ADDITIONAL: msg->ar_rrsets++; break; 415 default: log_assert(0); 416 } 417 if(!moveover_rrsigs(pkt, region, sigset, dataset, 418 msg->qtype == LDNS_RR_TYPE_RRSIG || 419 (msg->qtype == LDNS_RR_TYPE_ANY && 420 section != LDNS_SECTION_ANSWER) )) 421 return NULL; 422 return dataset; 423 } 424 /* changeover the type of the rrset to data set */ 425 msgparse_bucket_remove(msg, dataset); 426 /* insert into new hash bucket */ 427 dataset->rrset_bucket_next = msg->hashtable[hash&(PARSE_TABLE_SIZE-1)]; 428 msg->hashtable[hash&(PARSE_TABLE_SIZE-1)] = dataset; 429 dataset->hash = hash; 430 /* use section of data item for result */ 431 change_section(msg, dataset, section); 432 dataset->type = datatype; 433 dataset->flags = rrset_flags; 434 dataset->rrsig_count += dataset->rr_count; 435 dataset->rr_count = 0; 436 /* move sigs to end of siglist */ 437 if(dataset->rrsig_last) 438 dataset->rrsig_last->next = dataset->rr_first; 439 else dataset->rrsig_first = dataset->rr_first; 440 dataset->rrsig_last = dataset->rr_last; 441 dataset->rr_first = 0; 442 dataset->rr_last = 0; 443 return dataset; 444} 445 446/** Find rrset. If equal to previous it is fast. hash if not so. 447 * @param msg: the message with hash table. 448 * @param pkt: the packet in wireformat (needed for compression ptrs). 449 * @param dname: pointer to start of dname (compressed) in packet. 450 * @param dnamelen: uncompressed wirefmt length of dname. 451 * @param type: type of current rr. 452 * @param dclass: class of current rr. 453 * @param hash: hash value is returned if the rrset could not be found. 454 * @param rrset_flags: is returned if the rrset could not be found. 455 * @param prev_dname_first: dname of last seen RR. First seen dname. 456 * @param prev_dname_last: dname of last seen RR. Last seen dname. 457 * @param prev_dnamelen: dname len of last seen RR. 458 * @param prev_type: type of last seen RR. 459 * @param prev_dclass: class of last seen RR. 460 * @param rrset_prev: last seen RRset. 461 * @param section: the current section in the packet. 462 * @param region: used to allocate temporary parsing data. 463 * @return 0 on out of memory. 464 */ 465static int 466find_rrset(struct msg_parse* msg, sldns_buffer* pkt, uint8_t* dname, 467 size_t dnamelen, uint16_t type, uint16_t dclass, hashvalue_type* hash, 468 uint32_t* rrset_flags, 469 uint8_t** prev_dname_first, uint8_t** prev_dname_last, 470 size_t* prev_dnamelen, uint16_t* prev_type, 471 uint16_t* prev_dclass, struct rrset_parse** rrset_prev, 472 sldns_pkt_section section, struct regional* region) 473{ 474 hashvalue_type dname_h = pkt_hash_rrset_first(pkt, dname); 475 uint16_t covtype; 476 if(*rrset_prev) { 477 /* check if equal to previous item */ 478 if(type == *prev_type && dclass == *prev_dclass && 479 dnamelen == *prev_dnamelen && 480 smart_compare(pkt, dname, *prev_dname_first, 481 *prev_dname_last) == 0 && 482 type != LDNS_RR_TYPE_RRSIG) { 483 /* same as previous */ 484 *prev_dname_last = dname; 485 return 1; 486 } 487 /* check if rrsig over previous item */ 488 if(type == LDNS_RR_TYPE_RRSIG && dclass == *prev_dclass && 489 pkt_rrsig_covered_equals(pkt, sldns_buffer_current(pkt), 490 *prev_type) && 491 smart_compare(pkt, dname, *prev_dname_first, 492 *prev_dname_last) == 0) { 493 /* covers previous */ 494 *prev_dname_last = dname; 495 return 1; 496 } 497 } 498 /* find by hashing and lookup in hashtable */ 499 *rrset_flags = pkt_rrset_flags(pkt, type, section); 500 501 /* if rrsig - try to lookup matching data set first */ 502 if(type == LDNS_RR_TYPE_RRSIG && pkt_rrsig_covered(pkt, 503 sldns_buffer_current(pkt), &covtype)) { 504 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 505 *rrset_flags); 506 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 507 *rrset_flags, dname, dnamelen, covtype, dclass); 508 if(!*rrset_prev && covtype == LDNS_RR_TYPE_NSEC) { 509 /* if NSEC try with NSEC apex bit twiddled */ 510 *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; 511 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 512 *rrset_flags); 513 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 514 *hash, *rrset_flags, dname, dnamelen, covtype, 515 dclass); 516 if(!*rrset_prev) /* untwiddle if not found */ 517 *rrset_flags ^= PACKED_RRSET_NSEC_AT_APEX; 518 } 519 if(!*rrset_prev && covtype == LDNS_RR_TYPE_SOA) { 520 /* if SOA try with SOA neg flag twiddled */ 521 *rrset_flags ^= PACKED_RRSET_SOA_NEG; 522 *hash = pkt_hash_rrset_rest(dname_h, covtype, dclass, 523 *rrset_flags); 524 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, 525 *hash, *rrset_flags, dname, dnamelen, covtype, 526 dclass); 527 if(!*rrset_prev) /* untwiddle if not found */ 528 *rrset_flags ^= PACKED_RRSET_SOA_NEG; 529 } 530 if(*rrset_prev) { 531 *prev_dname_first = (*rrset_prev)->dname; 532 *prev_dname_last = dname; 533 *prev_dnamelen = dnamelen; 534 *prev_type = covtype; 535 *prev_dclass = dclass; 536 return 1; 537 } 538 } 539 if(type != LDNS_RR_TYPE_RRSIG) { 540 int hasother = 0; 541 /* find matching rrsig */ 542 *hash = pkt_hash_rrset_rest(dname_h, LDNS_RR_TYPE_RRSIG, 543 dclass, 0); 544 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, 545 0, dname, dnamelen, LDNS_RR_TYPE_RRSIG, 546 dclass); 547 if(*rrset_prev && rrset_has_sigover(pkt, *rrset_prev, type, 548 &hasother)) { 549 /* yes! */ 550 *prev_dname_first = (*rrset_prev)->dname; 551 *prev_dname_last = dname; 552 *prev_dnamelen = dnamelen; 553 *prev_type = type; 554 *prev_dclass = dclass; 555 *rrset_prev = change_rrsig_rrset(*rrset_prev, msg, 556 pkt, type, *rrset_flags, hasother, section, 557 region); 558 if(!*rrset_prev) return 0; 559 return 1; 560 } 561 } 562 563 *hash = pkt_hash_rrset_rest(dname_h, type, dclass, *rrset_flags); 564 *rrset_prev = msgparse_hashtable_lookup(msg, pkt, *hash, *rrset_flags, 565 dname, dnamelen, type, dclass); 566 if(*rrset_prev) 567 *prev_dname_first = (*rrset_prev)->dname; 568 else *prev_dname_first = dname; 569 *prev_dname_last = dname; 570 *prev_dnamelen = dnamelen; 571 *prev_type = type; 572 *prev_dclass = dclass; 573 return 1; 574} 575 576/** 577 * Parse query section. 578 * @param pkt: packet, position at call must be at start of query section. 579 * at end position is after query section. 580 * @param msg: store results here. 581 * @return: 0 if OK, or rcode on error. 582 */ 583static int 584parse_query_section(sldns_buffer* pkt, struct msg_parse* msg) 585{ 586 if(msg->qdcount == 0) 587 return 0; 588 if(msg->qdcount > 1) 589 return LDNS_RCODE_FORMERR; 590 log_assert(msg->qdcount == 1); 591 if(sldns_buffer_remaining(pkt) <= 0) 592 return LDNS_RCODE_FORMERR; 593 msg->qname = sldns_buffer_current(pkt); 594 if((msg->qname_len = pkt_dname_len(pkt)) == 0) 595 return LDNS_RCODE_FORMERR; 596 if(sldns_buffer_remaining(pkt) < sizeof(uint16_t)*2) 597 return LDNS_RCODE_FORMERR; 598 msg->qtype = sldns_buffer_read_u16(pkt); 599 msg->qclass = sldns_buffer_read_u16(pkt); 600 return 0; 601} 602 603size_t 604get_rdf_size(sldns_rdf_type rdf) 605{ 606 switch(rdf) { 607 case LDNS_RDF_TYPE_CLASS: 608 case LDNS_RDF_TYPE_ALG: 609 case LDNS_RDF_TYPE_INT8: 610 return 1; 611 break; 612 case LDNS_RDF_TYPE_INT16: 613 case LDNS_RDF_TYPE_TYPE: 614 case LDNS_RDF_TYPE_CERT_ALG: 615 return 2; 616 break; 617 case LDNS_RDF_TYPE_INT32: 618 case LDNS_RDF_TYPE_TIME: 619 case LDNS_RDF_TYPE_A: 620 case LDNS_RDF_TYPE_PERIOD: 621 return 4; 622 break; 623 case LDNS_RDF_TYPE_TSIGTIME: 624 return 6; 625 break; 626 case LDNS_RDF_TYPE_AAAA: 627 return 16; 628 break; 629 default: 630 log_assert(0); /* add type above */ 631 /* only types that appear before a domain * 632 * name are needed. rest is simply copied. */ 633 } 634 return 0; 635} 636 637/** calculate the size of one rr */ 638static int 639calc_size(sldns_buffer* pkt, uint16_t type, struct rr_parse* rr) 640{ 641 const sldns_rr_descriptor* desc; 642 uint16_t pkt_len; /* length of rr inside the packet */ 643 rr->size = sizeof(uint16_t); /* the rdatalen */ 644 sldns_buffer_skip(pkt, 4); /* skip ttl */ 645 pkt_len = sldns_buffer_read_u16(pkt); 646 if(sldns_buffer_remaining(pkt) < pkt_len) 647 return 0; 648 desc = sldns_rr_descript(type); 649 if(pkt_len > 0 && desc && desc->_dname_count > 0) { 650 int count = (int)desc->_dname_count; 651 int rdf = 0; 652 size_t len; 653 size_t oldpos; 654 /* skip first part. */ 655 while(pkt_len > 0 && count) { 656 switch(desc->_wireformat[rdf]) { 657 case LDNS_RDF_TYPE_DNAME: 658 /* decompress every domain name */ 659 oldpos = sldns_buffer_position(pkt); 660 if((len = pkt_dname_len(pkt)) == 0) 661 return 0; /* malformed dname */ 662 if(sldns_buffer_position(pkt)-oldpos > pkt_len) 663 return 0; /* dname exceeds rdata */ 664 pkt_len -= sldns_buffer_position(pkt)-oldpos; 665 rr->size += len; 666 count--; 667 len = 0; 668 break; 669 case LDNS_RDF_TYPE_STR: 670 if(pkt_len < 1) { 671 /* NOTREACHED, due to 'while(>0)' */ 672 return 0; /* len byte exceeds rdata */ 673 } 674 len = sldns_buffer_current(pkt)[0] + 1; 675 break; 676 default: 677 len = get_rdf_size(desc->_wireformat[rdf]); 678 } 679 if(len) { 680 if(pkt_len < len) 681 return 0; /* exceeds rdata */ 682 pkt_len -= len; 683 sldns_buffer_skip(pkt, (ssize_t)len); 684 rr->size += len; 685 } 686 rdf++; 687 } 688 } 689 /* remaining rdata */ 690 rr->size += pkt_len; 691 sldns_buffer_skip(pkt, (ssize_t)pkt_len); 692 return 1; 693} 694 695/** skip rr ttl and rdata */ 696static int 697skip_ttl_rdata(sldns_buffer* pkt) 698{ 699 uint16_t rdatalen; 700 if(sldns_buffer_remaining(pkt) < 6) /* ttl + rdatalen */ 701 return 0; 702 sldns_buffer_skip(pkt, 4); /* ttl */ 703 rdatalen = sldns_buffer_read_u16(pkt); 704 if(sldns_buffer_remaining(pkt) < rdatalen) 705 return 0; 706 sldns_buffer_skip(pkt, (ssize_t)rdatalen); 707 return 1; 708} 709 710/** see if RRSIG is a duplicate of another */ 711static int 712sig_is_double(sldns_buffer* pkt, struct rrset_parse* rrset, uint8_t* ttldata) 713{ 714 uint16_t rlen, siglen; 715 size_t pos = sldns_buffer_position(pkt); 716 struct rr_parse* sig; 717 if(sldns_buffer_remaining(pkt) < 6) 718 return 0; 719 sldns_buffer_skip(pkt, 4); /* ttl */ 720 rlen = sldns_buffer_read_u16(pkt); 721 if(sldns_buffer_remaining(pkt) < rlen) { 722 sldns_buffer_set_position(pkt, pos); 723 return 0; 724 } 725 sldns_buffer_set_position(pkt, pos); 726 727 sig = rrset->rrsig_first; 728 while(sig) { 729 /* check if rdatalen is same */ 730 memmove(&siglen, sig->ttl_data+4, sizeof(siglen)); 731 siglen = ntohs(siglen); 732 /* checks if data in packet is exactly the same, this means 733 * also dname in rdata is the same, but rrsig is not allowed 734 * to have compressed dnames anyway. If it is compressed anyway 735 * it will lead to duplicate rrs for qtype=RRSIG. (or ANY). 736 * 737 * Cannot use sig->size because size of the other one is not 738 * calculated yet. 739 */ 740 if(siglen == rlen) { 741 if(siglen>0 && memcmp(sig->ttl_data+6, ttldata+6, 742 siglen) == 0) { 743 /* same! */ 744 return 1; 745 } 746 } 747 sig = sig->next; 748 } 749 return 0; 750} 751 752/** Add rr (from packet here) to rrset, skips rr */ 753static int 754add_rr_to_rrset(struct rrset_parse* rrset, sldns_buffer* pkt, 755 struct msg_parse* msg, struct regional* region, 756 sldns_pkt_section section, uint16_t type) 757{ 758 struct rr_parse* rr; 759 /* check section of rrset. */ 760 if(rrset->section != section && type != LDNS_RR_TYPE_RRSIG && 761 rrset->type != LDNS_RR_TYPE_RRSIG) { 762 /* silently drop it - we drop the last part, since 763 * trust in rr data depends on the section it is in. 764 * the less trustworthy part is discarded. 765 * also the last part is more likely to be incomplete. 766 * RFC 2181: must put RRset only once in response. */ 767 /* 768 verbose(VERB_QUERY, "Packet contains rrset data in " 769 "multiple sections, dropped last part."); 770 log_buf(VERB_QUERY, "packet was", pkt); 771 */ 772 /* forwards */ 773 if(!skip_ttl_rdata(pkt)) 774 return LDNS_RCODE_FORMERR; 775 return 0; 776 } 777 778 if( (msg->qtype == LDNS_RR_TYPE_RRSIG || 779 msg->qtype == LDNS_RR_TYPE_ANY) 780 && sig_is_double(pkt, rrset, sldns_buffer_current(pkt))) { 781 if(!skip_ttl_rdata(pkt)) 782 return LDNS_RCODE_FORMERR; 783 return 0; 784 } 785 786 /* create rr */ 787 if(!(rr = (struct rr_parse*)regional_alloc(region, sizeof(*rr)))) 788 return LDNS_RCODE_SERVFAIL; 789 rr->outside_packet = 0; 790 rr->ttl_data = sldns_buffer_current(pkt); 791 rr->next = 0; 792 if(type == LDNS_RR_TYPE_RRSIG && rrset->type != LDNS_RR_TYPE_RRSIG) { 793 if(rrset->rrsig_last) 794 rrset->rrsig_last->next = rr; 795 else rrset->rrsig_first = rr; 796 rrset->rrsig_last = rr; 797 rrset->rrsig_count++; 798 } else { 799 if(rrset->rr_last) 800 rrset->rr_last->next = rr; 801 else rrset->rr_first = rr; 802 rrset->rr_last = rr; 803 rrset->rr_count++; 804 } 805 806 /* calc decompressed size */ 807 if(!calc_size(pkt, type, rr)) 808 return LDNS_RCODE_FORMERR; 809 rrset->size += rr->size; 810 811 return 0; 812} 813 814/** 815 * Parse packet RR section, for answer, authority and additional sections. 816 * @param pkt: packet, position at call must be at start of section. 817 * at end position is after section. 818 * @param msg: store results here. 819 * @param region: how to alloc results. 820 * @param section: section enum. 821 * @param num_rrs: how many rrs are in the section. 822 * @param num_rrsets: returns number of rrsets in the section. 823 * @return: 0 if OK, or rcode on error. 824 */ 825static int 826parse_section(sldns_buffer* pkt, struct msg_parse* msg, 827 struct regional* region, sldns_pkt_section section, 828 uint16_t num_rrs, size_t* num_rrsets) 829{ 830 uint16_t i; 831 uint8_t* dname, *prev_dname_f = NULL, *prev_dname_l = NULL; 832 size_t dnamelen, prev_dnamelen = 0; 833 uint16_t type, prev_type = 0; 834 uint16_t dclass, prev_dclass = 0; 835 uint32_t rrset_flags = 0; 836 hashvalue_type hash = 0; 837 struct rrset_parse* rrset = NULL; 838 int r; 839 840 if(num_rrs == 0) 841 return 0; 842 if(sldns_buffer_remaining(pkt) <= 0) 843 return LDNS_RCODE_FORMERR; 844 for(i=0; i<num_rrs; i++) { 845 /* parse this RR. */ 846 dname = sldns_buffer_current(pkt); 847 if((dnamelen = pkt_dname_len(pkt)) == 0) 848 return LDNS_RCODE_FORMERR; 849 if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, len */ 850 return LDNS_RCODE_FORMERR; 851 type = sldns_buffer_read_u16(pkt); 852 sldns_buffer_read(pkt, &dclass, sizeof(dclass)); 853 854 if(0) { /* debug show what is being parsed. */ 855 if(type == LDNS_RR_TYPE_RRSIG) { 856 uint16_t t; 857 if(pkt_rrsig_covered(pkt, 858 sldns_buffer_current(pkt), &t)) 859 fprintf(stderr, "parse of %s(%d) [%s(%d)]", 860 sldns_rr_descript(type)? 861 sldns_rr_descript(type)->_name: "??", 862 (int)type, 863 sldns_rr_descript(t)? 864 sldns_rr_descript(t)->_name: "??", 865 (int)t); 866 } else 867 fprintf(stderr, "parse of %s(%d)", 868 sldns_rr_descript(type)? 869 sldns_rr_descript(type)->_name: "??", 870 (int)type); 871 fprintf(stderr, " %s(%d) ", 872 sldns_lookup_by_id(sldns_rr_classes, 873 (int)ntohs(dclass))?sldns_lookup_by_id( 874 sldns_rr_classes, (int)ntohs(dclass))->name: 875 "??", (int)ntohs(dclass)); 876 dname_print(stderr, pkt, dname); 877 fprintf(stderr, "\n"); 878 } 879 880 /* see if it is part of an existing RR set */ 881 if(!find_rrset(msg, pkt, dname, dnamelen, type, dclass, &hash, 882 &rrset_flags, &prev_dname_f, &prev_dname_l, 883 &prev_dnamelen, &prev_type, &prev_dclass, &rrset, 884 section, region)) 885 return LDNS_RCODE_SERVFAIL; 886 if(!rrset) { 887 /* it is a new RR set. hash&flags already calculated.*/ 888 (*num_rrsets)++; 889 rrset = new_rrset(msg, dname, dnamelen, type, dclass, 890 hash, rrset_flags, section, region); 891 if(!rrset) 892 return LDNS_RCODE_SERVFAIL; 893 } 894 else if(0) { 895 fprintf(stderr, "is part of existing: "); 896 dname_print(stderr, pkt, rrset->dname); 897 fprintf(stderr, " type %s(%d)\n", 898 sldns_rr_descript(rrset->type)? 899 sldns_rr_descript(rrset->type)->_name: "??", 900 (int)rrset->type); 901 } 902 /* add to rrset. */ 903 if((r=add_rr_to_rrset(rrset, pkt, msg, region, section, 904 type)) != 0) 905 return r; 906 } 907 return 0; 908} 909 910int 911parse_packet(sldns_buffer* pkt, struct msg_parse* msg, struct regional* region) 912{ 913 int ret; 914 if(sldns_buffer_remaining(pkt) < LDNS_HEADER_SIZE) 915 return LDNS_RCODE_FORMERR; 916 /* read the header */ 917 sldns_buffer_read(pkt, &msg->id, sizeof(uint16_t)); 918 msg->flags = sldns_buffer_read_u16(pkt); 919 msg->qdcount = sldns_buffer_read_u16(pkt); 920 msg->ancount = sldns_buffer_read_u16(pkt); 921 msg->nscount = sldns_buffer_read_u16(pkt); 922 msg->arcount = sldns_buffer_read_u16(pkt); 923 if(msg->qdcount > 1) 924 return LDNS_RCODE_FORMERR; 925 if((ret = parse_query_section(pkt, msg)) != 0) 926 return ret; 927 if((ret = parse_section(pkt, msg, region, LDNS_SECTION_ANSWER, 928 msg->ancount, &msg->an_rrsets)) != 0) 929 return ret; 930 if((ret = parse_section(pkt, msg, region, LDNS_SECTION_AUTHORITY, 931 msg->nscount, &msg->ns_rrsets)) != 0) 932 return ret; 933 if(sldns_buffer_remaining(pkt) == 0 && msg->arcount == 1) { 934 /* BIND accepts leniently that an EDNS record is missing. 935 * so, we do too. */ 936 } else if((ret = parse_section(pkt, msg, region, 937 LDNS_SECTION_ADDITIONAL, msg->arcount, &msg->ar_rrsets)) != 0) 938 return ret; 939 /* if(sldns_buffer_remaining(pkt) > 0) { */ 940 /* there is spurious data at end of packet. ignore */ 941 /* } */ 942 msg->rrset_count = msg->an_rrsets + msg->ns_rrsets + msg->ar_rrsets; 943 return 0; 944} 945 946/** parse EDNS options from EDNS wireformat rdata */ 947static int 948parse_edns_options_from_query(uint8_t* rdata_ptr, size_t rdata_len, 949 struct edns_data* edns, struct config_file* cfg, struct comm_point* c, 950 struct comm_reply* repinfo, uint32_t now, struct regional* region) 951{ 952 /* To respond with a Keepalive option, the client connection must have 953 * received one message with a TCP Keepalive EDNS option, and that 954 * option must have 0 length data. Subsequent messages sent on that 955 * connection will have a TCP Keepalive option. 956 * 957 * In the if-statement below, the option is added unsolicited. This 958 * means that the client has sent an KEEPALIVE option earlier. We know 959 * here this is true, because c->tcp_keepalive is set. 960 */ 961 if (cfg && cfg->do_tcp_keepalive && c && c->type != comm_udp && c->tcp_keepalive) { 962 if(!edns_opt_list_append_keepalive(&edns->opt_list_out, 963 c->tcp_timeout_msec / 100, region)) { 964 log_err("out of memory"); 965 return LDNS_RCODE_SERVFAIL; 966 } 967 } 968 969 /* while still more options, and have code+len to read */ 970 /* ignores partial content (i.e. rdata len 3) */ 971 while(rdata_len >= 4) { 972 uint16_t opt_code = sldns_read_uint16(rdata_ptr); 973 uint16_t opt_len = sldns_read_uint16(rdata_ptr+2); 974 uint8_t server_cookie[40]; 975 enum edns_cookie_val_status cookie_val_status; 976 int cookie_is_v4 = 1; 977 978 rdata_ptr += 4; 979 rdata_len -= 4; 980 if(opt_len > rdata_len) 981 break; /* option code partial */ 982 983 /* handle parse time edns options here */ 984 switch(opt_code) { 985 case LDNS_EDNS_NSID: 986 if (!cfg || !cfg->nsid) 987 break; 988 if(!edns_opt_list_append(&edns->opt_list_out, 989 LDNS_EDNS_NSID, cfg->nsid_len, 990 cfg->nsid, region)) { 991 log_err("out of memory"); 992 return LDNS_RCODE_SERVFAIL; 993 } 994 break; 995 996 case LDNS_EDNS_KEEPALIVE: 997 /* To respond with a Keepalive option, the client 998 * connection must have received one message with a TCP 999 * Keepalive EDNS option, and that option must have 0 1000 * length data. Subsequent messages sent on that 1001 * connection will have a TCP Keepalive option. 1002 * 1003 * This should be the first time the client sends this 1004 * option, so c->tcp_keepalive is not set. 1005 * Besides adding the reply KEEPALIVE option, 1006 * c->tcp_keepalive will be set so that the 1007 * option will be added unsolicited in subsequent 1008 * responses (see the comment above the if-statement 1009 * at the start of this function). 1010 */ 1011 if (!cfg || !cfg->do_tcp_keepalive || !c || 1012 c->type == comm_udp || c->tcp_keepalive) 1013 break; 1014 if(opt_len) { 1015 verbose(VERB_ALGO, "query with bad edns keepalive."); 1016 return LDNS_RCODE_FORMERR; 1017 } 1018 if(!edns_opt_list_append_keepalive(&edns->opt_list_out, 1019 c->tcp_timeout_msec / 100, 1020 region)) { 1021 log_err("out of memory"); 1022 return LDNS_RCODE_SERVFAIL; 1023 } 1024 c->tcp_keepalive = 1; 1025 break; 1026 1027 case LDNS_EDNS_PADDING: 1028 if(!cfg || !cfg->pad_responses || 1029 !c || c->type != comm_tcp ||!c->ssl) 1030 break; 1031 if(!edns_opt_list_append(&edns->opt_list_out, 1032 LDNS_EDNS_PADDING, 1033 0, NULL, region)) { 1034 log_err("out of memory"); 1035 return LDNS_RCODE_SERVFAIL; 1036 } 1037 edns->padding_block_size = cfg->pad_responses_block_size; 1038 break; 1039 1040 case LDNS_EDNS_COOKIE: 1041 if(!cfg || !cfg->do_answer_cookie || !repinfo) 1042 break; 1043 if(opt_len != 8 && (opt_len < 16 || opt_len > 40)) { 1044 verbose(VERB_ALGO, "worker request: " 1045 "badly formatted cookie"); 1046 return LDNS_RCODE_FORMERR; 1047 } 1048 edns->cookie_present = 1; 1049 1050 /* Copy client cookie, version and timestamp for 1051 * validation and creation purposes. 1052 */ 1053 if(opt_len >= 16) { 1054 memmove(server_cookie, rdata_ptr, 16); 1055 } else { 1056 memset(server_cookie, 0, 16); 1057 memmove(server_cookie, rdata_ptr, opt_len); 1058 } 1059 1060 /* Copy client ip for validation and creation 1061 * purposes. It will be overwritten if (re)creation 1062 * is needed. 1063 */ 1064 if(repinfo->remote_addr.ss_family == AF_INET) { 1065 memcpy(server_cookie + 16, 1066 &((struct sockaddr_in*)&repinfo->remote_addr)->sin_addr, 4); 1067 } else { 1068 cookie_is_v4 = 0; 1069 memcpy(server_cookie + 16, 1070 &((struct sockaddr_in6*)&repinfo->remote_addr)->sin6_addr, 16); 1071 } 1072 1073 cookie_val_status = edns_cookie_server_validate( 1074 rdata_ptr, opt_len, cfg->cookie_secret, 1075 cfg->cookie_secret_len, cookie_is_v4, 1076 server_cookie, now); 1077 switch(cookie_val_status) { 1078 case COOKIE_STATUS_VALID: 1079 case COOKIE_STATUS_VALID_RENEW: 1080 edns->cookie_valid = 1; 1081 /* Reuse cookie */ 1082 if(!edns_opt_list_append( 1083 &edns->opt_list_out, LDNS_EDNS_COOKIE, 1084 opt_len, rdata_ptr, region)) { 1085 log_err("out of memory"); 1086 return LDNS_RCODE_SERVFAIL; 1087 } 1088 /* Cookie to be reused added to outgoing 1089 * options. Done! 1090 */ 1091 break; 1092 case COOKIE_STATUS_CLIENT_ONLY: 1093 edns->cookie_client = 1; 1094 /* fallthrough */ 1095 case COOKIE_STATUS_FUTURE: 1096 case COOKIE_STATUS_EXPIRED: 1097 case COOKIE_STATUS_INVALID: 1098 default: 1099 edns_cookie_server_write(server_cookie, 1100 cfg->cookie_secret, cookie_is_v4, now); 1101 if(!edns_opt_list_append(&edns->opt_list_out, 1102 LDNS_EDNS_COOKIE, 24, server_cookie, 1103 region)) { 1104 log_err("out of memory"); 1105 return LDNS_RCODE_SERVFAIL; 1106 } 1107 break; 1108 } 1109 break; 1110 default: 1111 break; 1112 } 1113 if(!edns_opt_list_append(&edns->opt_list_in, 1114 opt_code, opt_len, rdata_ptr, region)) { 1115 log_err("out of memory"); 1116 return LDNS_RCODE_SERVFAIL; 1117 } 1118 rdata_ptr += opt_len; 1119 rdata_len -= opt_len; 1120 } 1121 return LDNS_RCODE_NOERROR; 1122} 1123 1124int 1125parse_extract_edns_from_response_msg(struct msg_parse* msg, 1126 struct edns_data* edns, struct regional* region) 1127{ 1128 struct rrset_parse* rrset = msg->rrset_first; 1129 struct rrset_parse* prev = 0; 1130 struct rrset_parse* found = 0; 1131 struct rrset_parse* found_prev = 0; 1132 size_t rdata_len; 1133 uint8_t* rdata_ptr; 1134 /* since the class encodes the UDP size, we cannot use hash table to 1135 * find the EDNS OPT record. Scan the packet. */ 1136 while(rrset) { 1137 if(rrset->type == LDNS_RR_TYPE_OPT) { 1138 /* only one OPT RR allowed. */ 1139 if(found) return LDNS_RCODE_FORMERR; 1140 /* found it! */ 1141 found_prev = prev; 1142 found = rrset; 1143 } 1144 prev = rrset; 1145 rrset = rrset->rrset_all_next; 1146 } 1147 if(!found) { 1148 memset(edns, 0, sizeof(*edns)); 1149 edns->udp_size = 512; 1150 return 0; 1151 } 1152 /* check the found RRset */ 1153 /* most lenient check possible. ignore dname, use last opt */ 1154 if(found->section != LDNS_SECTION_ADDITIONAL) 1155 return LDNS_RCODE_FORMERR; 1156 if(found->rr_count == 0) 1157 return LDNS_RCODE_FORMERR; 1158 if(0) { /* strict checking of dname and RRcount */ 1159 if(found->dname_len != 1 || !found->dname 1160 || found->dname[0] != 0) return LDNS_RCODE_FORMERR; 1161 if(found->rr_count != 1) return LDNS_RCODE_FORMERR; 1162 } 1163 log_assert(found->rr_first && found->rr_last); 1164 1165 /* remove from packet */ 1166 if(found_prev) found_prev->rrset_all_next = found->rrset_all_next; 1167 else msg->rrset_first = found->rrset_all_next; 1168 if(found == msg->rrset_last) 1169 msg->rrset_last = found_prev; 1170 msg->arcount --; 1171 msg->ar_rrsets --; 1172 msg->rrset_count --; 1173 1174 /* take the data ! */ 1175 edns->edns_present = 1; 1176 edns->ext_rcode = found->rr_last->ttl_data[0]; 1177 edns->edns_version = found->rr_last->ttl_data[1]; 1178 edns->bits = sldns_read_uint16(&found->rr_last->ttl_data[2]); 1179 edns->udp_size = ntohs(found->rrset_class); 1180 edns->opt_list_in = NULL; 1181 edns->opt_list_out = NULL; 1182 edns->opt_list_inplace_cb_out = NULL; 1183 edns->padding_block_size = 0; 1184 edns->cookie_present = 0; 1185 edns->cookie_valid = 0; 1186 1187 /* take the options */ 1188 rdata_len = found->rr_first->size-2; 1189 rdata_ptr = found->rr_first->ttl_data+6; 1190 1191 /* while still more options, and have code+len to read */ 1192 /* ignores partial content (i.e. rdata len 3) */ 1193 while(rdata_len >= 4) { 1194 uint16_t opt_code = sldns_read_uint16(rdata_ptr); 1195 uint16_t opt_len = sldns_read_uint16(rdata_ptr+2); 1196 rdata_ptr += 4; 1197 rdata_len -= 4; 1198 if(opt_len > rdata_len) 1199 break; /* option code partial */ 1200 1201 if(!edns_opt_list_append(&edns->opt_list_in, 1202 opt_code, opt_len, rdata_ptr, region)) { 1203 log_err("out of memory"); 1204 break; 1205 } 1206 rdata_ptr += opt_len; 1207 rdata_len -= opt_len; 1208 } 1209 /* ignore rrsigs */ 1210 return LDNS_RCODE_NOERROR; 1211} 1212 1213/** skip RR in packet */ 1214static int 1215skip_pkt_rr(sldns_buffer* pkt) 1216{ 1217 if(sldns_buffer_remaining(pkt) < 1) return 0; 1218 if(!pkt_dname_len(pkt)) 1219 return 0; 1220 if(sldns_buffer_remaining(pkt) < 4) return 0; 1221 sldns_buffer_skip(pkt, 4); /* type and class */ 1222 if(!skip_ttl_rdata(pkt)) 1223 return 0; 1224 return 1; 1225} 1226 1227/** skip RRs from packet */ 1228int 1229skip_pkt_rrs(sldns_buffer* pkt, int num) 1230{ 1231 int i; 1232 for(i=0; i<num; i++) { 1233 if(!skip_pkt_rr(pkt)) 1234 return 0; 1235 } 1236 return 1; 1237} 1238 1239int 1240parse_edns_from_query_pkt(sldns_buffer* pkt, struct edns_data* edns, 1241 struct config_file* cfg, struct comm_point* c, 1242 struct comm_reply* repinfo, time_t now, struct regional* region) 1243{ 1244 size_t rdata_len; 1245 uint8_t* rdata_ptr; 1246 log_assert(LDNS_QDCOUNT(sldns_buffer_begin(pkt)) == 1); 1247 memset(edns, 0, sizeof(*edns)); 1248 if(LDNS_ANCOUNT(sldns_buffer_begin(pkt)) != 0 || 1249 LDNS_NSCOUNT(sldns_buffer_begin(pkt)) != 0) { 1250 if(!skip_pkt_rrs(pkt, ((int)LDNS_ANCOUNT(sldns_buffer_begin(pkt)))+ 1251 ((int)LDNS_NSCOUNT(sldns_buffer_begin(pkt))))) 1252 return LDNS_RCODE_FORMERR; 1253 } 1254 /* check edns section is present */ 1255 if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) > 1) { 1256 return LDNS_RCODE_FORMERR; 1257 } 1258 if(LDNS_ARCOUNT(sldns_buffer_begin(pkt)) == 0) { 1259 edns->udp_size = 512; 1260 return 0; 1261 } 1262 /* domain name must be the root of length 1. */ 1263 if(pkt_dname_len(pkt) != 1) 1264 return LDNS_RCODE_FORMERR; 1265 if(sldns_buffer_remaining(pkt) < 10) /* type, class, ttl, rdatalen */ 1266 return LDNS_RCODE_FORMERR; 1267 if(sldns_buffer_read_u16(pkt) != LDNS_RR_TYPE_OPT) 1268 return LDNS_RCODE_FORMERR; 1269 edns->edns_present = 1; 1270 edns->udp_size = sldns_buffer_read_u16(pkt); /* class is udp size */ 1271 edns->ext_rcode = sldns_buffer_read_u8(pkt); /* ttl used for bits */ 1272 edns->edns_version = sldns_buffer_read_u8(pkt); 1273 edns->bits = sldns_buffer_read_u16(pkt); 1274 edns->opt_list_in = NULL; 1275 edns->opt_list_out = NULL; 1276 edns->opt_list_inplace_cb_out = NULL; 1277 edns->padding_block_size = 0; 1278 edns->cookie_present = 0; 1279 edns->cookie_valid = 0; 1280 1281 /* take the options */ 1282 rdata_len = sldns_buffer_read_u16(pkt); 1283 if(sldns_buffer_remaining(pkt) < rdata_len) 1284 return LDNS_RCODE_FORMERR; 1285 rdata_ptr = sldns_buffer_current(pkt); 1286 /* ignore rrsigs */ 1287 return parse_edns_options_from_query(rdata_ptr, rdata_len, edns, cfg, 1288 c, repinfo, now, region); 1289} 1290 1291void 1292log_edns_opt_list(enum verbosity_value level, const char* info_str, 1293 struct edns_option* list) 1294{ 1295 if(verbosity >= level && list) { 1296 char str[128], *s; 1297 size_t slen; 1298 verbose(level, "%s", info_str); 1299 while(list) { 1300 s = str; 1301 slen = sizeof(str); 1302 (void)sldns_wire2str_edns_option_print(&s, &slen, list->opt_code, 1303 list->opt_data, list->opt_len); 1304 verbose(level, " %s", str); 1305 list = list->next; 1306 } 1307 } 1308} 1309 1310/** remove RR from msgparse RRset, return true if rrset is entirely bad */ 1311int 1312msgparse_rrset_remove_rr(const char* str, sldns_buffer* pkt, struct rrset_parse* rrset, 1313 struct rr_parse* prev, struct rr_parse* rr, struct sockaddr_storage* addr, socklen_t addrlen) 1314{ 1315 if(verbosity >= VERB_QUERY && rrset->dname_len <= LDNS_MAX_DOMAINLEN && str) { 1316 uint8_t buf[LDNS_MAX_DOMAINLEN+1]; 1317 dname_pkt_copy(pkt, buf, rrset->dname); 1318 if(addr) 1319 log_name_addr(VERB_QUERY, str, buf, addr, addrlen); 1320 else log_nametypeclass(VERB_QUERY, str, buf, 1321 rrset->type, ntohs(rrset->rrset_class)); 1322 } 1323 if(prev) 1324 prev->next = rr->next; 1325 else rrset->rr_first = rr->next; 1326 if(rrset->rr_last == rr) 1327 rrset->rr_last = prev; 1328 rrset->rr_count --; 1329 rrset->size -= rr->size; 1330 /* rr struct still exists, but is unlinked, so that in the for loop 1331 * the rr->next works fine to continue. */ 1332 return rrset->rr_count == 0; 1333} 1334