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