1 /* $OpenBSD: mft.c,v 1.93 2023/05/22 15:15:25 tb Exp $ */ 2 /* 3 * Copyright (c) 2022 Theo Buehler <tb@openbsd.org> 4 * Copyright (c) 2019 Kristaps Dzonsons <kristaps@bsd.lv> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <assert.h> 20 #include <err.h> 21 #include <limits.h> 22 #include <stdint.h> 23 #include <stdlib.h> 24 #include <string.h> 25 #include <unistd.h> 26 27 #include <openssl/bn.h> 28 #include <openssl/asn1.h> 29 #include <openssl/asn1t.h> 30 #include <openssl/safestack.h> 31 #include <openssl/sha.h> 32 #include <openssl/stack.h> 33 #include <openssl/x509.h> 34 35 #include "extern.h" 36 37 /* 38 * Parse results and data of the manifest file. 39 */ 40 struct parse { 41 const char *fn; /* manifest file name */ 42 struct mft *res; /* result object */ 43 int found_crl; 44 }; 45 46 extern ASN1_OBJECT *mft_oid; 47 48 /* 49 * Types and templates for the Manifest eContent, RFC 6486, section 4.2. 50 */ 51 52 typedef struct { 53 ASN1_IA5STRING *file; 54 ASN1_BIT_STRING *hash; 55 } FileAndHash; 56 57 DECLARE_STACK_OF(FileAndHash); 58 59 #ifndef DEFINE_STACK_OF 60 #define sk_FileAndHash_num(sk) SKM_sk_num(FileAndHash, (sk)) 61 #define sk_FileAndHash_value(sk, i) SKM_sk_value(FileAndHash, (sk), (i)) 62 #endif 63 64 typedef struct { 65 ASN1_INTEGER *version; 66 ASN1_INTEGER *manifestNumber; 67 ASN1_GENERALIZEDTIME *thisUpdate; 68 ASN1_GENERALIZEDTIME *nextUpdate; 69 ASN1_OBJECT *fileHashAlg; 70 STACK_OF(FileAndHash) *fileList; 71 } Manifest; 72 73 ASN1_SEQUENCE(FileAndHash) = { 74 ASN1_SIMPLE(FileAndHash, file, ASN1_IA5STRING), 75 ASN1_SIMPLE(FileAndHash, hash, ASN1_BIT_STRING), 76 } ASN1_SEQUENCE_END(FileAndHash); 77 78 ASN1_SEQUENCE(Manifest) = { 79 ASN1_EXP_OPT(Manifest, version, ASN1_INTEGER, 0), 80 ASN1_SIMPLE(Manifest, manifestNumber, ASN1_INTEGER), 81 ASN1_SIMPLE(Manifest, thisUpdate, ASN1_GENERALIZEDTIME), 82 ASN1_SIMPLE(Manifest, nextUpdate, ASN1_GENERALIZEDTIME), 83 ASN1_SIMPLE(Manifest, fileHashAlg, ASN1_OBJECT), 84 ASN1_SEQUENCE_OF(Manifest, fileList, FileAndHash), 85 } ASN1_SEQUENCE_END(Manifest); 86 87 DECLARE_ASN1_FUNCTIONS(Manifest); 88 IMPLEMENT_ASN1_FUNCTIONS(Manifest); 89 90 #define GENTIME_LENGTH 15 91 92 /* 93 * Convert an ASN1_GENERALIZEDTIME to a struct tm. 94 * Returns 1 on success, 0 on failure. 95 */ 96 static int 97 generalizedtime_to_tm(const ASN1_GENERALIZEDTIME *gtime, struct tm *tm) 98 { 99 /* 100 * ASN1_GENERALIZEDTIME is another name for ASN1_STRING. Check type and 101 * length, so we don't accidentally accept a UTCTime. Punt on checking 102 * Zulu time for OpenSSL: we don't want to mess about with silly flags. 103 */ 104 if (ASN1_STRING_type(gtime) != V_ASN1_GENERALIZEDTIME) 105 return 0; 106 if (ASN1_STRING_length(gtime) != GENTIME_LENGTH) 107 return 0; 108 109 memset(tm, 0, sizeof(*tm)); 110 return ASN1_TIME_to_tm(gtime, tm); 111 } 112 113 /* 114 * Validate and verify the time validity of the mft. 115 * Returns 1 if all is good and for any other case 0. 116 */ 117 static int 118 mft_parse_time(const ASN1_GENERALIZEDTIME *from, 119 const ASN1_GENERALIZEDTIME *until, struct parse *p) 120 { 121 struct tm tm_from, tm_until; 122 123 if (!generalizedtime_to_tm(from, &tm_from)) { 124 warnx("%s: embedded from time format invalid", p->fn); 125 return 0; 126 } 127 if (!generalizedtime_to_tm(until, &tm_until)) { 128 warnx("%s: embedded until time format invalid", p->fn); 129 return 0; 130 } 131 132 if ((p->res->thisupdate = timegm(&tm_from)) == -1 || 133 (p->res->nextupdate = timegm(&tm_until)) == -1) 134 errx(1, "%s: timegm failed", p->fn); 135 136 if (p->res->thisupdate > p->res->nextupdate) { 137 warnx("%s: bad update interval", p->fn); 138 return 0; 139 } 140 141 return 1; 142 } 143 144 /* 145 * Determine rtype corresponding to file extension. Returns RTYPE_INVALID 146 * on error or unkown extension. 147 */ 148 enum rtype 149 rtype_from_file_extension(const char *fn) 150 { 151 size_t sz; 152 153 sz = strlen(fn); 154 if (sz < 5) 155 return RTYPE_INVALID; 156 157 if (strcasecmp(fn + sz - 4, ".tal") == 0) 158 return RTYPE_TAL; 159 if (strcasecmp(fn + sz - 4, ".cer") == 0) 160 return RTYPE_CER; 161 if (strcasecmp(fn + sz - 4, ".crl") == 0) 162 return RTYPE_CRL; 163 if (strcasecmp(fn + sz - 4, ".mft") == 0) 164 return RTYPE_MFT; 165 if (strcasecmp(fn + sz - 4, ".roa") == 0) 166 return RTYPE_ROA; 167 if (strcasecmp(fn + sz - 4, ".gbr") == 0) 168 return RTYPE_GBR; 169 if (strcasecmp(fn + sz - 4, ".sig") == 0) 170 return RTYPE_RSC; 171 if (strcasecmp(fn + sz - 4, ".asa") == 0) 172 return RTYPE_ASPA; 173 if (strcasecmp(fn + sz - 4, ".tak") == 0) 174 return RTYPE_TAK; 175 if (strcasecmp(fn + sz - 4, ".csv") == 0) 176 return RTYPE_GEOFEED; 177 178 return RTYPE_INVALID; 179 } 180 181 /* 182 * Validate that a filename listed on a Manifest only contains characters 183 * permitted in draft-ietf-sidrops-6486bis section 4.2.2 184 * Also ensure that there is exactly one '.'. 185 */ 186 static int 187 valid_mft_filename(const char *fn, size_t len) 188 { 189 const unsigned char *c; 190 191 if (!valid_filename(fn, len)) 192 return 0; 193 194 c = memchr(fn, '.', len); 195 if (c == NULL || c != memrchr(fn, '.', len)) 196 return 0; 197 198 return 1; 199 } 200 201 /* 202 * Check that the file is allowed to be part of a manifest and the parser 203 * for this type is implemented in rpki-client. 204 * Returns corresponding rtype or RTYPE_INVALID to mark the file as unknown. 205 */ 206 static enum rtype 207 rtype_from_mftfile(const char *fn) 208 { 209 enum rtype type; 210 211 type = rtype_from_file_extension(fn); 212 switch (type) { 213 case RTYPE_CER: 214 case RTYPE_CRL: 215 case RTYPE_GBR: 216 case RTYPE_ROA: 217 case RTYPE_ASPA: 218 case RTYPE_TAK: 219 return type; 220 default: 221 return RTYPE_INVALID; 222 } 223 } 224 225 /* 226 * Parse an individual "FileAndHash", RFC 6486, sec. 4.2. 227 * Return zero on failure, non-zero on success. 228 */ 229 static int 230 mft_parse_filehash(struct parse *p, const FileAndHash *fh) 231 { 232 char *fn = NULL; 233 int rc = 0; 234 struct mftfile *fent; 235 enum rtype type; 236 237 if (!valid_mft_filename(fh->file->data, fh->file->length)) { 238 warnx("%s: RFC 6486 section 4.2.2: bad filename", p->fn); 239 goto out; 240 } 241 fn = strndup(fh->file->data, fh->file->length); 242 if (fn == NULL) 243 err(1, NULL); 244 245 if (fh->hash->length != SHA256_DIGEST_LENGTH) { 246 warnx("%s: RFC 6486 section 4.2.1: hash: " 247 "invalid SHA256 length, have %d", 248 p->fn, fh->hash->length); 249 goto out; 250 } 251 252 type = rtype_from_mftfile(fn); 253 /* remember the filehash for the CRL in struct mft */ 254 if (type == RTYPE_CRL && strcmp(fn, p->res->crl) == 0) { 255 memcpy(p->res->crlhash, fh->hash->data, SHA256_DIGEST_LENGTH); 256 p->found_crl = 1; 257 } 258 259 /* Insert the filename and hash value. */ 260 fent = &p->res->files[p->res->filesz++]; 261 fent->type = type; 262 fent->file = fn; 263 fn = NULL; 264 memcpy(fent->hash, fh->hash->data, SHA256_DIGEST_LENGTH); 265 266 rc = 1; 267 out: 268 free(fn); 269 return rc; 270 } 271 272 /* 273 * Handle the eContent of the manifest object, RFC 6486 sec. 4.2. 274 * Returns 0 on failure and 1 on success. 275 */ 276 static int 277 mft_parse_econtent(const unsigned char *d, size_t dsz, struct parse *p) 278 { 279 Manifest *mft; 280 FileAndHash *fh; 281 int i, rc = 0; 282 283 if ((mft = d2i_Manifest(NULL, &d, dsz)) == NULL) { 284 cryptowarnx("%s: RFC 6486 section 4: failed to parse Manifest", 285 p->fn); 286 goto out; 287 } 288 289 if (!valid_econtent_version(p->fn, mft->version)) 290 goto out; 291 292 p->res->seqnum = x509_convert_seqnum(p->fn, mft->manifestNumber); 293 if (p->res->seqnum == NULL) 294 goto out; 295 296 /* 297 * Timestamps: this and next update time. 298 * Validate that the current date falls into this interval. 299 * This is required by section 4.4, (3). 300 * If we're after the given date, then the MFT is stale. 301 * This is made super complicated because it uses OpenSSL's 302 * ASN1_GENERALIZEDTIME instead of ASN1_TIME, which we could 303 * compare against the current time trivially. 304 */ 305 306 if (!mft_parse_time(mft->thisUpdate, mft->nextUpdate, p)) 307 goto out; 308 309 if (OBJ_obj2nid(mft->fileHashAlg) != NID_sha256) { 310 warnx("%s: RFC 6486 section 4.2.1: fileHashAlg: " 311 "want SHA256 object, have %s (NID %d)", p->fn, 312 ASN1_tag2str(OBJ_obj2nid(mft->fileHashAlg)), 313 OBJ_obj2nid(mft->fileHashAlg)); 314 goto out; 315 } 316 317 if (sk_FileAndHash_num(mft->fileList) >= MAX_MANIFEST_ENTRIES) { 318 warnx("%s: %d exceeds manifest entry limit (%d)", p->fn, 319 sk_FileAndHash_num(mft->fileList), MAX_MANIFEST_ENTRIES); 320 goto out; 321 } 322 323 p->res->files = calloc(sk_FileAndHash_num(mft->fileList), 324 sizeof(struct mftfile)); 325 if (p->res->files == NULL) 326 err(1, NULL); 327 328 for (i = 0; i < sk_FileAndHash_num(mft->fileList); i++) { 329 fh = sk_FileAndHash_value(mft->fileList, i); 330 if (!mft_parse_filehash(p, fh)) 331 goto out; 332 } 333 334 if (!p->found_crl) { 335 warnx("%s: CRL not part of MFT fileList", p->fn); 336 goto out; 337 } 338 339 rc = 1; 340 out: 341 Manifest_free(mft); 342 return rc; 343 } 344 345 /* 346 * Parse the objects that have been published in the manifest. 347 * This conforms to RFC 6486. 348 * Note that if the MFT is stale, all referenced objects are stripped 349 * from the parsed content. 350 * The MFT content is otherwise returned. 351 */ 352 struct mft * 353 mft_parse(X509 **x509, const char *fn, const unsigned char *der, size_t len) 354 { 355 struct parse p; 356 int rc = 0; 357 size_t cmsz; 358 unsigned char *cms; 359 char *crldp = NULL, *crlfile; 360 time_t signtime = 0; 361 362 memset(&p, 0, sizeof(struct parse)); 363 p.fn = fn; 364 365 cms = cms_parse_validate(x509, fn, der, len, mft_oid, &cmsz, &signtime); 366 if (cms == NULL) 367 return NULL; 368 assert(*x509 != NULL); 369 370 if ((p.res = calloc(1, sizeof(struct mft))) == NULL) 371 err(1, NULL); 372 p.res->signtime = signtime; 373 374 if (!x509_get_aia(*x509, fn, &p.res->aia)) 375 goto out; 376 if (!x509_get_aki(*x509, fn, &p.res->aki)) 377 goto out; 378 if (!x509_get_sia(*x509, fn, &p.res->sia)) 379 goto out; 380 if (!x509_get_ski(*x509, fn, &p.res->ski)) 381 goto out; 382 if (p.res->aia == NULL || p.res->aki == NULL || p.res->sia == NULL || 383 p.res->ski == NULL) { 384 warnx("%s: RFC 6487 section 4.8: " 385 "missing AIA, AKI, SIA, or SKI X509 extension", fn); 386 goto out; 387 } 388 389 if (!x509_inherits(*x509)) { 390 warnx("%s: RFC 3779 extension not set to inherit", fn); 391 goto out; 392 } 393 394 /* get CRL info for later */ 395 if (!x509_get_crl(*x509, fn, &crldp)) 396 goto out; 397 if (crldp == NULL) { 398 warnx("%s: RFC 6487 section 4.8.6: CRL: " 399 "missing CRL distribution point extension", fn); 400 goto out; 401 } 402 crlfile = strrchr(crldp, '/'); 403 if (crlfile == NULL) { 404 warnx("%s: RFC 6487 section 4.8.6: " 405 "invalid CRL distribution point", fn); 406 goto out; 407 } 408 crlfile++; 409 if (!valid_mft_filename(crlfile, strlen(crlfile)) || 410 rtype_from_file_extension(crlfile) != RTYPE_CRL) { 411 warnx("%s: RFC 6487 section 4.8.6: CRL: " 412 "bad CRL distribution point extension", fn); 413 goto out; 414 } 415 if ((p.res->crl = strdup(crlfile)) == NULL) 416 err(1, NULL); 417 418 if (mft_parse_econtent(cms, cmsz, &p) == 0) 419 goto out; 420 421 if (p.res->signtime > p.res->nextupdate) { 422 warnx("%s: dating issue: CMS signing-time after MFT nextUpdate", 423 fn); 424 goto out; 425 } 426 427 rc = 1; 428 out: 429 if (rc == 0) { 430 mft_free(p.res); 431 p.res = NULL; 432 X509_free(*x509); 433 *x509 = NULL; 434 } 435 free(crldp); 436 free(cms); 437 return p.res; 438 } 439 440 /* 441 * Free an MFT pointer. 442 * Safe to call with NULL. 443 */ 444 void 445 mft_free(struct mft *p) 446 { 447 size_t i; 448 449 if (p == NULL) 450 return; 451 452 if (p->files != NULL) 453 for (i = 0; i < p->filesz; i++) 454 free(p->files[i].file); 455 456 free(p->aia); 457 free(p->aki); 458 free(p->sia); 459 free(p->ski); 460 free(p->path); 461 free(p->files); 462 free(p->seqnum); 463 free(p); 464 } 465 466 /* 467 * Serialise MFT parsed content into the given buffer. 468 * See mft_read() for the other side of the pipe. 469 */ 470 void 471 mft_buffer(struct ibuf *b, const struct mft *p) 472 { 473 size_t i; 474 475 io_simple_buffer(b, &p->stale, sizeof(p->stale)); 476 io_simple_buffer(b, &p->repoid, sizeof(p->repoid)); 477 io_simple_buffer(b, &p->talid, sizeof(p->talid)); 478 io_str_buffer(b, p->path); 479 480 io_str_buffer(b, p->aia); 481 io_str_buffer(b, p->aki); 482 io_str_buffer(b, p->ski); 483 484 io_simple_buffer(b, &p->filesz, sizeof(size_t)); 485 for (i = 0; i < p->filesz; i++) { 486 io_str_buffer(b, p->files[i].file); 487 io_simple_buffer(b, &p->files[i].type, 488 sizeof(p->files[i].type)); 489 io_simple_buffer(b, &p->files[i].location, 490 sizeof(p->files[i].location)); 491 io_simple_buffer(b, p->files[i].hash, SHA256_DIGEST_LENGTH); 492 } 493 } 494 495 /* 496 * Read an MFT structure from the file descriptor. 497 * Result must be passed to mft_free(). 498 */ 499 struct mft * 500 mft_read(struct ibuf *b) 501 { 502 struct mft *p = NULL; 503 size_t i; 504 505 if ((p = calloc(1, sizeof(struct mft))) == NULL) 506 err(1, NULL); 507 508 io_read_buf(b, &p->stale, sizeof(p->stale)); 509 io_read_buf(b, &p->repoid, sizeof(p->repoid)); 510 io_read_buf(b, &p->talid, sizeof(p->talid)); 511 io_read_str(b, &p->path); 512 513 io_read_str(b, &p->aia); 514 io_read_str(b, &p->aki); 515 io_read_str(b, &p->ski); 516 assert(p->aia && p->aki && p->ski); 517 518 io_read_buf(b, &p->filesz, sizeof(size_t)); 519 if ((p->files = calloc(p->filesz, sizeof(struct mftfile))) == NULL) 520 err(1, NULL); 521 522 for (i = 0; i < p->filesz; i++) { 523 io_read_str(b, &p->files[i].file); 524 io_read_buf(b, &p->files[i].type, sizeof(p->files[i].type)); 525 io_read_buf(b, &p->files[i].location, 526 sizeof(p->files[i].location)); 527 io_read_buf(b, p->files[i].hash, SHA256_DIGEST_LENGTH); 528 } 529 530 return p; 531 } 532 533 /* 534 * Compare two MFT files, returns 1 if first MFT is preferred and 0 if second 535 * MFT should be used. 536 */ 537 int 538 mft_compare(const struct mft *a, const struct mft *b) 539 { 540 int r; 541 542 if (b == NULL) 543 return 1; 544 if (a == NULL) 545 return 0; 546 547 r = strlen(a->seqnum) - strlen(b->seqnum); 548 if (r > 0) /* seqnum in a is longer -> higher */ 549 return 1; 550 if (r < 0) /* seqnum in a is shorter -> smaller */ 551 return 0; 552 553 r = strcmp(a->seqnum, b->seqnum); 554 if (r > 0) /* a is greater, prefer a */ 555 return 1; 556 return 0; 557 } 558