1/* 2 * validator/val_utils.h - validator utility functions. 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/** 37 * \file 38 * 39 * This file contains helper functions for the validator module. 40 */ 41 42#ifndef VALIDATOR_VAL_UTILS_H 43#define VALIDATOR_VAL_UTILS_H 44#include "util/data/packed_rrset.h" 45#include "sldns/pkthdr.h" 46#include "sldns/rrdef.h" 47struct query_info; 48struct reply_info; 49struct val_env; 50struct module_env; 51struct module_qstate; 52struct ub_packed_rrset_key; 53struct key_entry_key; 54struct regional; 55struct val_anchors; 56struct rrset_cache; 57struct sock_list; 58 59/** 60 * Response classifications for the validator. The different types of proofs. 61 */ 62enum val_classification { 63 /** Not subtyped yet. */ 64 VAL_CLASS_UNTYPED = 0, 65 /** Not a recognized subtype. */ 66 VAL_CLASS_UNKNOWN, 67 /** A positive, direct, response */ 68 VAL_CLASS_POSITIVE, 69 /** A positive response, with a CNAME/DNAME chain. */ 70 VAL_CLASS_CNAME, 71 /** A NOERROR/NODATA response. */ 72 VAL_CLASS_NODATA, 73 /** A NXDOMAIN response. */ 74 VAL_CLASS_NAMEERROR, 75 /** A CNAME/DNAME chain, and the offset is at the end of it, 76 * but there is no answer here, it can be NAMEERROR or NODATA. */ 77 VAL_CLASS_CNAMENOANSWER, 78 /** A referral, from cache with a nonRD query. */ 79 VAL_CLASS_REFERRAL, 80 /** A response to a qtype=ANY query. */ 81 VAL_CLASS_ANY 82}; 83 84/** 85 * Given a response, classify ANSWER responses into a subtype. 86 * @param query_flags: query flags for the original query. 87 * @param origqinf: query info. The original query name. 88 * @param qinf: query info. The chased query name. 89 * @param rep: response. The original response. 90 * @param skip: offset into the original response answer section. 91 * @return A subtype, all values possible except UNTYPED . 92 * Once CNAME type is returned you can increase skip. 93 * Then, another CNAME type, CNAME_NOANSWER or POSITIVE are possible. 94 */ 95enum val_classification val_classify_response(uint16_t query_flags, 96 struct query_info* origqinf, struct query_info* qinf, 97 struct reply_info* rep, size_t skip); 98 99/** 100 * Given a response, determine the name of the "signer". This is primarily 101 * to determine if the response is, in fact, signed at all, and, if so, what 102 * is the name of the most pertinent keyset. 103 * 104 * @param subtype: the type from classify. 105 * @param qinf: query, the chased query name. 106 * @param rep: response to that, original response. 107 * @param cname_skip: how many answer rrsets have been skipped due to CNAME 108 * chains being chased around. 109 * @param signer_name: signer name, if the response is signed 110 * (even partially), or null if the response isn't signed. 111 * @param signer_len: length of signer_name of 0 if signer_name is NULL. 112 */ 113void val_find_signer(enum val_classification subtype, 114 struct query_info* qinf, struct reply_info* rep, 115 size_t cname_skip, uint8_t** signer_name, size_t* signer_len); 116 117/** 118 * Verify RRset with keys from a keyset. 119 * @param env: module environment (scratch buffer) 120 * @param ve: validator environment (verification settings) 121 * @param rrset: what to verify 122 * @param kkey: key_entry to verify with. 123 * @param reason: reason of failure. Fixed string or alloced in scratch. 124 * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure. 125 * @param section: section of packet where this rrset comes from. 126 * @param qstate: qstate with region. 127 * @param verified: if not NULL, the number of RRSIG validations is returned. 128 * @return security status of verification. 129 */ 130enum sec_status val_verify_rrset_entry(struct module_env* env, 131 struct val_env* ve, struct ub_packed_rrset_key* rrset, 132 struct key_entry_key* kkey, char** reason, sldns_ede_code *reason_bogus, 133 sldns_pkt_section section, struct module_qstate* qstate, 134 int* verified); 135 136/** 137 * Verify DNSKEYs with DS rrset. Like val_verify_new_DNSKEYs but 138 * returns a sec_status instead of a key_entry. 139 * @param env: module environment (scratch buffer) 140 * @param ve: validator environment (verification settings) 141 * @param dnskey_rrset: DNSKEY rrset to verify 142 * @param ds_rrset: DS rrset to verify with. 143 * @param sigalg: if nonNULL provide downgrade protection otherwise one 144 * algorithm is enough. The list of signalled algorithms is returned, 145 * must have enough space for ALGO_NEEDS_MAX+1. 146 * @param reason: reason of failure. Fixed string or alloced in scratch. 147 * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure. 148 * @param qstate: qstate with region. 149 * @return: sec_status_secure if a DS matches. 150 * sec_status_insecure if end of trust (i.e., unknown algorithms). 151 * sec_status_bogus if it fails. 152 */ 153enum sec_status val_verify_DNSKEY_with_DS(struct module_env* env, 154 struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, 155 struct ub_packed_rrset_key* ds_rrset, uint8_t* sigalg, char** reason, 156 sldns_ede_code *reason_bogus, struct module_qstate* qstate); 157 158/** 159 * Verify DNSKEYs with DS and DNSKEY rrset. Like val_verify_DNSKEY_with_DS 160 * but for a trust anchor. 161 * @param env: module environment (scratch buffer) 162 * @param ve: validator environment (verification settings) 163 * @param dnskey_rrset: DNSKEY rrset to verify 164 * @param ta_ds: DS rrset to verify with. 165 * @param ta_dnskey: DNSKEY rrset to verify with. 166 * @param sigalg: if nonNULL provide downgrade protection otherwise one 167 * algorithm is enough. The list of signalled algorithms is returned, 168 * must have enough space for ALGO_NEEDS_MAX+1. 169 * @param reason: reason of failure. Fixed string or alloced in scratch. 170* @param reason_bogus: EDE (RFC8914) code paired with the reason of failure. 171 * @param qstate: qstate with region. 172 * @return: sec_status_secure if a DS matches. 173 * sec_status_insecure if end of trust (i.e., unknown algorithms). 174 * sec_status_bogus if it fails. 175 */ 176enum sec_status val_verify_DNSKEY_with_TA(struct module_env* env, 177 struct val_env* ve, struct ub_packed_rrset_key* dnskey_rrset, 178 struct ub_packed_rrset_key* ta_ds, 179 struct ub_packed_rrset_key* ta_dnskey, uint8_t* sigalg, char** reason, 180 sldns_ede_code *reason_bogus, struct module_qstate* qstate); 181 182/** 183 * Verify new DNSKEYs with DS rrset. The DS contains hash values that should 184 * match the DNSKEY keys. 185 * match the DS to a DNSKEY and verify the DNSKEY rrset with that key. 186 * 187 * @param region: where to allocate key entry result. 188 * @param env: module environment (scratch buffer) 189 * @param ve: validator environment (verification settings) 190 * @param dnskey_rrset: DNSKEY rrset to verify 191 * @param ds_rrset: DS rrset to verify with. 192 * @param downprot: if true provide downgrade protection otherwise one 193 * algorithm is enough. 194 * @param reason: reason of failure. Fixed string or alloced in scratch. 195 * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure. 196 * @param qstate: qstate with region. 197 * @return a KeyEntry. This will either contain the now trusted 198 * dnskey_rrset, a "null" key entry indicating that this DS 199 * rrset/DNSKEY pair indicate an secure end to the island of trust 200 * (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey 201 * rrset fails to verify. Note that the "null" response should 202 * generally only occur in a private algorithm scenario: normally 203 * this sort of thing is checked before fetching the matching DNSKEY 204 * rrset. 205 * if downprot is set, a key entry with an algo list is made. 206 */ 207struct key_entry_key* val_verify_new_DNSKEYs(struct regional* region, 208 struct module_env* env, struct val_env* ve, 209 struct ub_packed_rrset_key* dnskey_rrset, 210 struct ub_packed_rrset_key* ds_rrset, int downprot, char** reason, 211 sldns_ede_code *reason_bogus, struct module_qstate* qstate); 212 213/** 214 * Verify rrset with trust anchor: DS and DNSKEY rrset. 215 * 216 * @param region: where to allocate key entry result. 217 * @param env: module environment (scratch buffer) 218 * @param ve: validator environment (verification settings) 219 * @param dnskey_rrset: DNSKEY rrset to verify 220 * @param ta_ds_rrset: DS rrset to verify with. 221 * @param ta_dnskey_rrset: the DNSKEY rrset to verify with. 222 * @param downprot: if true provide downgrade protection otherwise one 223 * algorithm is enough. 224 * @param reason: reason of failure. Fixed string or alloced in scratch. 225 * @param reason_bogus: EDE (RFC8914) code paired with the reason of failure. 226 * @param qstate: qstate with region. 227 * @return a KeyEntry. This will either contain the now trusted 228 * dnskey_rrset, a "null" key entry indicating that this DS 229 * rrset/DNSKEY pair indicate an secure end to the island of trust 230 * (i.e., unknown algorithms), or a "bad" KeyEntry if the dnskey 231 * rrset fails to verify. Note that the "null" response should 232 * generally only occur in a private algorithm scenario: normally 233 * this sort of thing is checked before fetching the matching DNSKEY 234 * rrset. 235 * if downprot is set, a key entry with an algo list is made. 236 */ 237struct key_entry_key* val_verify_new_DNSKEYs_with_ta(struct regional* region, 238 struct module_env* env, struct val_env* ve, 239 struct ub_packed_rrset_key* dnskey_rrset, 240 struct ub_packed_rrset_key* ta_ds_rrset, 241 struct ub_packed_rrset_key* ta_dnskey_rrset, int downprot, 242 char** reason, sldns_ede_code *reason_bogus, struct module_qstate* qstate); 243 244/** 245 * Determine if DS rrset is usable for validator or not. 246 * Returns true if the algorithms for key and DShash are supported, 247 * for at least one RR. 248 * 249 * @param ds_rrset: the newly received DS rrset. 250 * @return true or false if not usable. 251 */ 252int val_dsset_isusable(struct ub_packed_rrset_key* ds_rrset); 253 254/** 255 * Determine by looking at a signed RRset whether or not the RRset name was 256 * the result of a wildcard expansion. If so, return the name of the 257 * generating wildcard. 258 * 259 * @param rrset The rrset to check. 260 * @param wc: the wildcard name, if the rrset was synthesized from a wildcard. 261 * unchanged if not. The wildcard name, without "*." in front, is 262 * returned. This is a pointer into the rrset owner name. 263 * @param wc_len: the length of the returned wildcard name. 264 * @return false if the signatures are inconsistent in indicating the 265 * wildcard status; possible spoofing of wildcard response for other 266 * responses is being tried. We lost the status which rrsig was verified 267 * after the verification routine finished, so we simply check if 268 * the signatures are consistent; inserting a fake signature is a denial 269 * of service; but in that you could also have removed the real 270 * signature anyway. 271 */ 272int val_rrset_wildcard(struct ub_packed_rrset_key* rrset, uint8_t** wc, 273 size_t* wc_len); 274 275/** 276 * Chase the cname to the next query name. 277 * @param qchase: the current query name, updated to next target. 278 * @param rep: original message reply to look at CNAMEs. 279 * @param cname_skip: the skip into the answer section. Updated to skip 280 * DNAME and CNAME to the next part of the answer. 281 * @return false on error (bad rdata). 282 */ 283int val_chase_cname(struct query_info* qchase, struct reply_info* rep, 284 size_t* cname_skip); 285 286/** 287 * Fill up the chased reply with the content from the original reply; 288 * as pointers to those rrsets. Select the part after the cname_skip into 289 * the answer section, NS and AR sections that are signed with same signer. 290 * 291 * @param chase: chased reply, filled up. 292 * @param orig: original reply. 293 * @param cname_skip: which part of the answer section to skip. 294 * The skipped part contains CNAME(and DNAME)s that have been chased. 295 * @param name: the signer name to look for. 296 * @param len: length of name. 297 * @param signer: signer name or NULL if an unsigned RRset is considered. 298 * If NULL, rrsets with the lookup name are copied over. 299 */ 300void val_fill_reply(struct reply_info* chase, struct reply_info* orig, 301 size_t cname_skip, uint8_t* name, size_t len, uint8_t* signer); 302 303/** 304 * Remove rrset with index from reply, from the authority section. 305 * @param rep: reply to remove it from. 306 * @param index: rrset to remove, must be in the authority section. 307 */ 308void val_reply_remove_auth(struct reply_info* rep, size_t index); 309 310/** 311 * Remove all unsigned or non-secure status rrsets from NS and AR sections. 312 * So that unsigned data does not get let through to clients, when we have 313 * found the data to be secure. 314 * 315 * @param env: environment with cleaning options. 316 * @param rep: reply to dump all nonsecure stuff out of. 317 */ 318void val_check_nonsecure(struct module_env* env, struct reply_info* rep); 319 320/** 321 * Mark all unchecked rrset entries not below a trust anchor as indeterminate. 322 * Only security==unchecked rrsets are updated. 323 * @param rep: the reply with rrsets. 324 * @param anchors: the trust anchors. 325 * @param r: rrset cache to store updated security status into. 326 * @param env: module environment 327 */ 328void val_mark_indeterminate(struct reply_info* rep, 329 struct val_anchors* anchors, struct rrset_cache* r, 330 struct module_env* env); 331 332/** 333 * Mark all unchecked rrset entries below a NULL key entry as insecure. 334 * Only security==unchecked rrsets are updated. 335 * @param rep: the reply with rrsets. 336 * @param kname: end of secure space name. 337 * @param r: rrset cache to store updated security status into. 338 * @param env: module environment 339 */ 340void val_mark_insecure(struct reply_info* rep, uint8_t* kname, 341 struct rrset_cache* r, struct module_env* env); 342 343/** 344 * Find next unchecked rrset position, return it for skip. 345 * @param rep: the original reply to look into. 346 * @param skip: the skip now. 347 * @return new skip, which may be at the rep->rrset_count position to signal 348 * there are no unchecked items. 349 */ 350size_t val_next_unchecked(struct reply_info* rep, size_t skip); 351 352/** 353 * Find the signer name for an RRset. 354 * @param rrset: the rrset. 355 * @param sname: signer name is returned or NULL if not signed. 356 * @param slen: length of sname (or 0). 357 */ 358void val_find_rrset_signer(struct ub_packed_rrset_key* rrset, uint8_t** sname, 359 size_t* slen); 360 361/** 362 * Get string to denote the classification result. 363 * @param subtype: from classification function. 364 * @return static string to describe the classification. 365 */ 366const char* val_classification_to_string(enum val_classification subtype); 367 368/** 369 * Add existing list to blacklist. 370 * @param blacklist: the blacklist with result 371 * @param region: the region where blacklist is allocated. 372 * Allocation failures are logged. 373 * @param origin: origin list to add, if NULL, a cache-entry is added to 374 * the blacklist to stop cache from being used. 375 * @param cross: if true this is a cross-qstate copy, and the 'origin' 376 * list is not allocated in the same region as the blacklist. 377 */ 378void val_blacklist(struct sock_list** blacklist, struct regional* region, 379 struct sock_list* origin, int cross); 380 381/** 382 * check if has dnssec info, and if it has signed nsecs. gives error reason. 383 * @param rep: reply to check. 384 * @param reason: returned on fail. 385 * @return false if message has no signed nsecs. Can not prove negatives. 386 */ 387int val_has_signed_nsecs(struct reply_info* rep, char** reason); 388 389/** 390 * Return algo number for favorite (best) algorithm that we support in DS. 391 * @param ds_rrset: the DSes in this rrset are inspected and best algo chosen. 392 * @return algo number or 0 if none supported. 0 is unused as algo number. 393 */ 394int val_favorite_ds_algo(struct ub_packed_rrset_key* ds_rrset); 395 396/** 397 * Find DS denial message in cache. Saves new qstate allocation and allows 398 * the validator to use partial content which is not enough to construct a 399 * message for network (or user) consumption. Without SOA for example, 400 * which is a common occurrence in the unbound code since the referrals contain 401 * NSEC/NSEC3 rrs without the SOA element, thus do not allow synthesis of a 402 * full negative reply, but do allow synthesis of sufficient proof. 403 * @param env: query env with caches and time. 404 * @param nm: name of DS record sought. 405 * @param nmlen: length of name. 406 * @param c: class of DS RR. 407 * @param region: where to allocate result. 408 * @param topname: name of the key that is currently in use, that will get 409 * used to validate the result, and thus no higher entries from the 410 * negative cache need to be examined. 411 * @return a dns_msg on success. NULL on failure. 412 */ 413struct dns_msg* val_find_DS(struct module_env* env, uint8_t* nm, size_t nmlen, 414 uint16_t c, struct regional* region, uint8_t* topname); 415 416#endif /* VALIDATOR_VAL_UTILS_H */ 417