1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* X.509 certificate parser 3 * 4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) "X.509: "fmt 9 #include <linux/kernel.h> 10 #include <linux/export.h> 11 #include <linux/slab.h> 12 #include <linux/err.h> 13 #include <linux/oid_registry.h> 14 #include <crypto/public_key.h> 15 #include "x509_parser.h" 16 #include "x509.asn1.h" 17 #include "x509_akid.asn1.h" 18 19 struct x509_parse_context { 20 struct x509_certificate *cert; /* Certificate being constructed */ 21 unsigned long data; /* Start of data */ 22 const void *key; /* Key data */ 23 size_t key_size; /* Size of key data */ 24 const void *params; /* Key parameters */ 25 size_t params_size; /* Size of key parameters */ 26 enum OID key_algo; /* Algorithm used by the cert's key */ 27 enum OID last_oid; /* Last OID encountered */ 28 enum OID sig_algo; /* Algorithm used to sign the cert */ 29 u8 o_size; /* Size of organizationName (O) */ 30 u8 cn_size; /* Size of commonName (CN) */ 31 u8 email_size; /* Size of emailAddress */ 32 u16 o_offset; /* Offset of organizationName (O) */ 33 u16 cn_offset; /* Offset of commonName (CN) */ 34 u16 email_offset; /* Offset of emailAddress */ 35 unsigned raw_akid_size; 36 const void *raw_akid; /* Raw authorityKeyId in ASN.1 */ 37 const void *akid_raw_issuer; /* Raw directoryName in authorityKeyId */ 38 unsigned akid_raw_issuer_size; 39 }; 40 41 /* 42 * Free an X.509 certificate 43 */ 44 void x509_free_certificate(struct x509_certificate *cert) 45 { 46 if (cert) { 47 public_key_free(cert->pub); 48 public_key_signature_free(cert->sig); 49 kfree(cert->issuer); 50 kfree(cert->subject); 51 kfree(cert->id); 52 kfree(cert->skid); 53 kfree(cert); 54 } 55 } 56 EXPORT_SYMBOL_GPL(x509_free_certificate); 57 58 /* 59 * Parse an X.509 certificate 60 */ 61 struct x509_certificate *x509_cert_parse(const void *data, size_t datalen) 62 { 63 struct x509_certificate *cert __free(x509_free_certificate) = NULL; 64 struct x509_parse_context *ctx __free(kfree) = NULL; 65 struct asymmetric_key_id *kid; 66 long ret; 67 68 cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL); 69 if (!cert) 70 return ERR_PTR(-ENOMEM); 71 cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL); 72 if (!cert->pub) 73 return ERR_PTR(-ENOMEM); 74 cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL); 75 if (!cert->sig) 76 return ERR_PTR(-ENOMEM); 77 ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL); 78 if (!ctx) 79 return ERR_PTR(-ENOMEM); 80 81 ctx->cert = cert; 82 ctx->data = (unsigned long)data; 83 84 /* Attempt to decode the certificate */ 85 ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen); 86 if (ret < 0) 87 return ERR_PTR(ret); 88 89 /* Decode the AuthorityKeyIdentifier */ 90 if (ctx->raw_akid) { 91 pr_devel("AKID: %u %*phN\n", 92 ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid); 93 ret = asn1_ber_decoder(&x509_akid_decoder, ctx, 94 ctx->raw_akid, ctx->raw_akid_size); 95 if (ret < 0) { 96 pr_warn("Couldn't decode AuthKeyIdentifier\n"); 97 return ERR_PTR(ret); 98 } 99 } 100 101 cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL); 102 if (!cert->pub->key) 103 return ERR_PTR(-ENOMEM); 104 105 cert->pub->keylen = ctx->key_size; 106 107 cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL); 108 if (!cert->pub->params) 109 return ERR_PTR(-ENOMEM); 110 111 cert->pub->paramlen = ctx->params_size; 112 cert->pub->algo = ctx->key_algo; 113 114 /* Grab the signature bits */ 115 ret = x509_get_sig_params(cert); 116 if (ret < 0) 117 return ERR_PTR(ret); 118 119 /* Generate cert issuer + serial number key ID */ 120 kid = asymmetric_key_generate_id(cert->raw_serial, 121 cert->raw_serial_size, 122 cert->raw_issuer, 123 cert->raw_issuer_size); 124 if (IS_ERR(kid)) 125 return ERR_CAST(kid); 126 cert->id = kid; 127 128 /* Detect self-signed certificates */ 129 ret = x509_check_for_self_signed(cert); 130 if (ret < 0) 131 return ERR_PTR(ret); 132 133 return_ptr(cert); 134 } 135 EXPORT_SYMBOL_GPL(x509_cert_parse); 136 137 /* 138 * Note an OID when we find one for later processing when we know how 139 * to interpret it. 140 */ 141 int x509_note_OID(void *context, size_t hdrlen, 142 unsigned char tag, 143 const void *value, size_t vlen) 144 { 145 struct x509_parse_context *ctx = context; 146 147 ctx->last_oid = look_up_OID(value, vlen); 148 if (ctx->last_oid == OID__NR) { 149 char buffer[50]; 150 sprint_oid(value, vlen, buffer, sizeof(buffer)); 151 pr_debug("Unknown OID: [%lu] %s\n", 152 (unsigned long)value - ctx->data, buffer); 153 } 154 return 0; 155 } 156 157 /* 158 * Save the position of the TBS data so that we can check the signature over it 159 * later. 160 */ 161 int x509_note_tbs_certificate(void *context, size_t hdrlen, 162 unsigned char tag, 163 const void *value, size_t vlen) 164 { 165 struct x509_parse_context *ctx = context; 166 167 pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n", 168 hdrlen, tag, (unsigned long)value - ctx->data, vlen); 169 170 ctx->cert->tbs = value - hdrlen; 171 ctx->cert->tbs_size = vlen + hdrlen; 172 return 0; 173 } 174 175 /* 176 * Record the algorithm that was used to sign this certificate. 177 */ 178 int x509_note_sig_algo(void *context, size_t hdrlen, unsigned char tag, 179 const void *value, size_t vlen) 180 { 181 struct x509_parse_context *ctx = context; 182 183 pr_debug("PubKey Algo: %u\n", ctx->last_oid); 184 185 switch (ctx->last_oid) { 186 default: 187 return -ENOPKG; /* Unsupported combination */ 188 189 case OID_sha1WithRSAEncryption: 190 ctx->cert->sig->hash_algo = "sha1"; 191 goto rsa_pkcs1; 192 193 case OID_sha256WithRSAEncryption: 194 ctx->cert->sig->hash_algo = "sha256"; 195 goto rsa_pkcs1; 196 197 case OID_sha384WithRSAEncryption: 198 ctx->cert->sig->hash_algo = "sha384"; 199 goto rsa_pkcs1; 200 201 case OID_sha512WithRSAEncryption: 202 ctx->cert->sig->hash_algo = "sha512"; 203 goto rsa_pkcs1; 204 205 case OID_sha224WithRSAEncryption: 206 ctx->cert->sig->hash_algo = "sha224"; 207 goto rsa_pkcs1; 208 209 case OID_id_ecdsa_with_sha1: 210 ctx->cert->sig->hash_algo = "sha1"; 211 goto ecdsa; 212 213 case OID_id_rsassa_pkcs1_v1_5_with_sha3_256: 214 ctx->cert->sig->hash_algo = "sha3-256"; 215 goto rsa_pkcs1; 216 217 case OID_id_rsassa_pkcs1_v1_5_with_sha3_384: 218 ctx->cert->sig->hash_algo = "sha3-384"; 219 goto rsa_pkcs1; 220 221 case OID_id_rsassa_pkcs1_v1_5_with_sha3_512: 222 ctx->cert->sig->hash_algo = "sha3-512"; 223 goto rsa_pkcs1; 224 225 case OID_id_ecdsa_with_sha224: 226 ctx->cert->sig->hash_algo = "sha224"; 227 goto ecdsa; 228 229 case OID_id_ecdsa_with_sha256: 230 ctx->cert->sig->hash_algo = "sha256"; 231 goto ecdsa; 232 233 case OID_id_ecdsa_with_sha384: 234 ctx->cert->sig->hash_algo = "sha384"; 235 goto ecdsa; 236 237 case OID_id_ecdsa_with_sha512: 238 ctx->cert->sig->hash_algo = "sha512"; 239 goto ecdsa; 240 241 case OID_id_ecdsa_with_sha3_256: 242 ctx->cert->sig->hash_algo = "sha3-256"; 243 goto ecdsa; 244 245 case OID_id_ecdsa_with_sha3_384: 246 ctx->cert->sig->hash_algo = "sha3-384"; 247 goto ecdsa; 248 249 case OID_id_ecdsa_with_sha3_512: 250 ctx->cert->sig->hash_algo = "sha3-512"; 251 goto ecdsa; 252 253 case OID_gost2012Signature256: 254 ctx->cert->sig->hash_algo = "streebog256"; 255 goto ecrdsa; 256 257 case OID_gost2012Signature512: 258 ctx->cert->sig->hash_algo = "streebog512"; 259 goto ecrdsa; 260 case OID_id_ml_dsa_44: 261 ctx->cert->sig->pkey_algo = "mldsa44"; 262 goto ml_dsa; 263 case OID_id_ml_dsa_65: 264 ctx->cert->sig->pkey_algo = "mldsa65"; 265 goto ml_dsa; 266 case OID_id_ml_dsa_87: 267 ctx->cert->sig->pkey_algo = "mldsa87"; 268 goto ml_dsa; 269 } 270 271 rsa_pkcs1: 272 ctx->cert->sig->pkey_algo = "rsa"; 273 ctx->cert->sig->encoding = "pkcs1"; 274 ctx->sig_algo = ctx->last_oid; 275 return 0; 276 ecrdsa: 277 ctx->cert->sig->pkey_algo = "ecrdsa"; 278 ctx->cert->sig->encoding = "raw"; 279 ctx->sig_algo = ctx->last_oid; 280 return 0; 281 ecdsa: 282 ctx->cert->sig->pkey_algo = "ecdsa"; 283 ctx->cert->sig->encoding = "x962"; 284 ctx->sig_algo = ctx->last_oid; 285 return 0; 286 ml_dsa: 287 ctx->cert->sig->algo_takes_data = true; 288 ctx->cert->sig->hash_algo = "none"; 289 ctx->cert->sig->encoding = "raw"; 290 ctx->sig_algo = ctx->last_oid; 291 return 0; 292 } 293 294 /* 295 * Note the whereabouts and type of the signature. 296 */ 297 int x509_note_signature(void *context, size_t hdrlen, 298 unsigned char tag, 299 const void *value, size_t vlen) 300 { 301 struct x509_parse_context *ctx = context; 302 303 pr_debug("Signature: alg=%u, size=%zu\n", ctx->last_oid, vlen); 304 305 /* 306 * In X.509 certificates, the signature's algorithm is stored in two 307 * places: inside the TBSCertificate (the data that is signed), and 308 * alongside the signature. These *must* match. 309 */ 310 if (ctx->last_oid != ctx->sig_algo) { 311 pr_warn("signatureAlgorithm (%u) differs from tbsCertificate.signature (%u)\n", 312 ctx->last_oid, ctx->sig_algo); 313 return -EINVAL; 314 } 315 316 if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 || 317 strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0 || 318 strcmp(ctx->cert->sig->pkey_algo, "ecdsa") == 0 || 319 strncmp(ctx->cert->sig->pkey_algo, "mldsa", 5) == 0) { 320 /* Discard the BIT STRING metadata */ 321 if (vlen < 1 || *(const u8 *)value != 0) 322 return -EBADMSG; 323 324 value++; 325 vlen--; 326 } 327 328 ctx->cert->raw_sig = value; 329 ctx->cert->raw_sig_size = vlen; 330 return 0; 331 } 332 333 /* 334 * Note the certificate serial number 335 */ 336 int x509_note_serial(void *context, size_t hdrlen, 337 unsigned char tag, 338 const void *value, size_t vlen) 339 { 340 struct x509_parse_context *ctx = context; 341 ctx->cert->raw_serial = value; 342 ctx->cert->raw_serial_size = vlen; 343 return 0; 344 } 345 346 /* 347 * Note some of the name segments from which we'll fabricate a name. 348 */ 349 int x509_extract_name_segment(void *context, size_t hdrlen, 350 unsigned char tag, 351 const void *value, size_t vlen) 352 { 353 struct x509_parse_context *ctx = context; 354 355 switch (ctx->last_oid) { 356 case OID_commonName: 357 ctx->cn_size = vlen; 358 ctx->cn_offset = (unsigned long)value - ctx->data; 359 break; 360 case OID_organizationName: 361 ctx->o_size = vlen; 362 ctx->o_offset = (unsigned long)value - ctx->data; 363 break; 364 case OID_email_address: 365 ctx->email_size = vlen; 366 ctx->email_offset = (unsigned long)value - ctx->data; 367 break; 368 default: 369 break; 370 } 371 372 return 0; 373 } 374 375 /* 376 * Fabricate and save the issuer and subject names 377 */ 378 static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen, 379 unsigned char tag, 380 char **_name, size_t vlen) 381 { 382 const void *name, *data = (const void *)ctx->data; 383 size_t namesize; 384 char *buffer; 385 386 if (*_name) 387 return -EINVAL; 388 389 /* Empty name string if no material */ 390 if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) { 391 buffer = kzalloc(1, GFP_KERNEL); 392 if (!buffer) 393 return -ENOMEM; 394 goto done; 395 } 396 397 if (ctx->cn_size && ctx->o_size) { 398 /* Consider combining O and CN, but use only the CN if it is 399 * prefixed by the O, or a significant portion thereof. 400 */ 401 namesize = ctx->cn_size; 402 name = data + ctx->cn_offset; 403 if (ctx->cn_size >= ctx->o_size && 404 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 405 ctx->o_size) == 0) 406 goto single_component; 407 if (ctx->cn_size >= 7 && 408 ctx->o_size >= 7 && 409 memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0) 410 goto single_component; 411 412 buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1, 413 GFP_KERNEL); 414 if (!buffer) 415 return -ENOMEM; 416 417 memcpy(buffer, 418 data + ctx->o_offset, ctx->o_size); 419 buffer[ctx->o_size + 0] = ':'; 420 buffer[ctx->o_size + 1] = ' '; 421 memcpy(buffer + ctx->o_size + 2, 422 data + ctx->cn_offset, ctx->cn_size); 423 buffer[ctx->o_size + 2 + ctx->cn_size] = 0; 424 goto done; 425 426 } else if (ctx->cn_size) { 427 namesize = ctx->cn_size; 428 name = data + ctx->cn_offset; 429 } else if (ctx->o_size) { 430 namesize = ctx->o_size; 431 name = data + ctx->o_offset; 432 } else { 433 namesize = ctx->email_size; 434 name = data + ctx->email_offset; 435 } 436 437 single_component: 438 buffer = kmalloc(namesize + 1, GFP_KERNEL); 439 if (!buffer) 440 return -ENOMEM; 441 memcpy(buffer, name, namesize); 442 buffer[namesize] = 0; 443 444 done: 445 *_name = buffer; 446 ctx->cn_size = 0; 447 ctx->o_size = 0; 448 ctx->email_size = 0; 449 return 0; 450 } 451 452 int x509_note_issuer(void *context, size_t hdrlen, 453 unsigned char tag, 454 const void *value, size_t vlen) 455 { 456 struct x509_parse_context *ctx = context; 457 struct asymmetric_key_id *kid; 458 459 ctx->cert->raw_issuer = value; 460 ctx->cert->raw_issuer_size = vlen; 461 462 if (!ctx->cert->sig->auth_ids[2]) { 463 kid = asymmetric_key_generate_id(value, vlen, "", 0); 464 if (IS_ERR(kid)) 465 return PTR_ERR(kid); 466 ctx->cert->sig->auth_ids[2] = kid; 467 } 468 469 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen); 470 } 471 472 int x509_note_subject(void *context, size_t hdrlen, 473 unsigned char tag, 474 const void *value, size_t vlen) 475 { 476 struct x509_parse_context *ctx = context; 477 ctx->cert->raw_subject = value; 478 ctx->cert->raw_subject_size = vlen; 479 return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen); 480 } 481 482 /* 483 * Extract the parameters for the public key 484 */ 485 int x509_note_params(void *context, size_t hdrlen, 486 unsigned char tag, 487 const void *value, size_t vlen) 488 { 489 struct x509_parse_context *ctx = context; 490 491 /* 492 * AlgorithmIdentifier is used three times in the x509, we should skip 493 * first and ignore third, using second one which is after subject and 494 * before subjectPublicKey. 495 */ 496 if (!ctx->cert->raw_subject || ctx->key) 497 return 0; 498 ctx->params = value - hdrlen; 499 ctx->params_size = vlen + hdrlen; 500 return 0; 501 } 502 503 /* 504 * Extract the data for the public key algorithm 505 */ 506 int x509_extract_key_data(void *context, size_t hdrlen, 507 unsigned char tag, 508 const void *value, size_t vlen) 509 { 510 struct x509_parse_context *ctx = context; 511 enum OID oid; 512 513 ctx->key_algo = ctx->last_oid; 514 switch (ctx->last_oid) { 515 case OID_rsaEncryption: 516 ctx->cert->pub->pkey_algo = "rsa"; 517 break; 518 case OID_gost2012PKey256: 519 case OID_gost2012PKey512: 520 ctx->cert->pub->pkey_algo = "ecrdsa"; 521 break; 522 case OID_id_ecPublicKey: 523 if (parse_OID(ctx->params, ctx->params_size, &oid) != 0) 524 return -EBADMSG; 525 526 switch (oid) { 527 case OID_id_prime192v1: 528 ctx->cert->pub->pkey_algo = "ecdsa-nist-p192"; 529 break; 530 case OID_id_prime256v1: 531 ctx->cert->pub->pkey_algo = "ecdsa-nist-p256"; 532 break; 533 case OID_id_ansip384r1: 534 ctx->cert->pub->pkey_algo = "ecdsa-nist-p384"; 535 break; 536 case OID_id_ansip521r1: 537 ctx->cert->pub->pkey_algo = "ecdsa-nist-p521"; 538 break; 539 default: 540 return -ENOPKG; 541 } 542 break; 543 case OID_id_ml_dsa_44: 544 ctx->cert->pub->pkey_algo = "mldsa44"; 545 break; 546 case OID_id_ml_dsa_65: 547 ctx->cert->pub->pkey_algo = "mldsa65"; 548 break; 549 case OID_id_ml_dsa_87: 550 ctx->cert->pub->pkey_algo = "mldsa87"; 551 break; 552 default: 553 return -ENOPKG; 554 } 555 556 /* Discard the BIT STRING metadata */ 557 if (vlen < 1 || *(const u8 *)value != 0) 558 return -EBADMSG; 559 ctx->key = value + 1; 560 ctx->key_size = vlen - 1; 561 return 0; 562 } 563 564 /* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */ 565 #define SEQ_TAG_KEYID (ASN1_CONT << 6) 566 567 /* 568 * Process certificate extensions that are used to qualify the certificate. 569 */ 570 int x509_process_extension(void *context, size_t hdrlen, 571 unsigned char tag, 572 const void *value, size_t vlen) 573 { 574 struct x509_parse_context *ctx = context; 575 struct asymmetric_key_id *kid; 576 const unsigned char *v = value; 577 578 pr_debug("Extension: %u\n", ctx->last_oid); 579 580 if (ctx->last_oid == OID_subjectKeyIdentifier) { 581 /* Get hold of the key fingerprint */ 582 if (ctx->cert->skid || vlen < 3) 583 return -EBADMSG; 584 if (v[0] != ASN1_OTS || v[1] != vlen - 2) 585 return -EBADMSG; 586 v += 2; 587 vlen -= 2; 588 589 ctx->cert->raw_skid_size = vlen; 590 ctx->cert->raw_skid = v; 591 kid = asymmetric_key_generate_id(v, vlen, "", 0); 592 if (IS_ERR(kid)) 593 return PTR_ERR(kid); 594 ctx->cert->skid = kid; 595 pr_debug("subjkeyid %*phN\n", kid->len, kid->data); 596 return 0; 597 } 598 599 if (ctx->last_oid == OID_keyUsage) { 600 /* 601 * Get hold of the keyUsage bit string 602 * v[1] is the encoding size 603 * (Expect either 0x02 or 0x03, making it 1 or 2 bytes) 604 * v[2] is the number of unused bits in the bit string 605 * (If >= 3 keyCertSign is missing when v[1] = 0x02) 606 * v[3] and possibly v[4] contain the bit string 607 * 608 * From RFC 5280 4.2.1.3: 609 * 0x04 is where keyCertSign lands in this bit string 610 * 0x80 is where digitalSignature lands in this bit string 611 */ 612 if (v[0] != ASN1_BTS) 613 return -EBADMSG; 614 if (vlen < 4) 615 return -EBADMSG; 616 if (v[2] >= 8) 617 return -EBADMSG; 618 if (v[3] & 0x80) 619 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_DIGITALSIG; 620 if (v[1] == 0x02 && v[2] <= 2 && (v[3] & 0x04)) 621 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN; 622 else if (vlen > 4 && v[1] == 0x03 && (v[3] & 0x04)) 623 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_KEYCERTSIGN; 624 return 0; 625 } 626 627 if (ctx->last_oid == OID_authorityKeyIdentifier) { 628 /* Get hold of the CA key fingerprint */ 629 ctx->raw_akid = v; 630 ctx->raw_akid_size = vlen; 631 return 0; 632 } 633 634 if (ctx->last_oid == OID_basicConstraints) { 635 /* 636 * Get hold of the basicConstraints 637 * v[1] is the encoding size 638 * (Expect 0x00 for empty SEQUENCE with CA:FALSE, or 639 * 0x03 or greater for non-empty SEQUENCE) 640 * v[2] is the encoding type 641 * (Expect an ASN1_BOOL for the CA) 642 * v[3] is the length of the ASN1_BOOL 643 * (Expect 1 for a single byte boolean) 644 * v[4] is the contents of the ASN1_BOOL 645 * (Expect 0xFF if the CA is TRUE) 646 * vlen should match the entire extension size 647 */ 648 if (v[0] != (ASN1_CONS_BIT | ASN1_SEQ)) 649 return -EBADMSG; 650 if (vlen < 2) 651 return -EBADMSG; 652 if (v[1] != vlen - 2) 653 return -EBADMSG; 654 /* Empty SEQUENCE means CA:FALSE (default value omitted per DER) */ 655 if (v[1] == 0) 656 return 0; 657 if (vlen >= 5 && v[2] == ASN1_BOOL && v[3] == 1 && v[4] == 0xFF) 658 ctx->cert->pub->key_eflags |= 1 << KEY_EFLAG_CA; 659 else 660 return -EBADMSG; 661 return 0; 662 } 663 664 return 0; 665 } 666 667 /** 668 * x509_decode_time - Decode an X.509 time ASN.1 object 669 * @_t: The time to fill in 670 * @hdrlen: The length of the object header 671 * @tag: The object tag 672 * @value: The object value 673 * @vlen: The size of the object value 674 * 675 * Decode an ASN.1 universal time or generalised time field into a struct the 676 * kernel can handle and check it for validity. The time is decoded thus: 677 * 678 * [RFC5280 §4.1.2.5] 679 * CAs conforming to this profile MUST always encode certificate validity 680 * dates through the year 2049 as UTCTime; certificate validity dates in 681 * 2050 or later MUST be encoded as GeneralizedTime. Conforming 682 * applications MUST be able to process validity dates that are encoded in 683 * either UTCTime or GeneralizedTime. 684 */ 685 int x509_decode_time(time64_t *_t, size_t hdrlen, 686 unsigned char tag, 687 const unsigned char *value, size_t vlen) 688 { 689 static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30, 690 31, 31, 30, 31, 30, 31 }; 691 const unsigned char *p = value; 692 unsigned year, mon, day, hour, min, sec, mon_len; 693 694 #define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; }) 695 #define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; }) 696 697 if (tag == ASN1_UNITIM) { 698 /* UTCTime: YYMMDDHHMMSSZ */ 699 if (vlen != 13) 700 goto unsupported_time; 701 year = DD2bin(p); 702 if (year >= 50) 703 year += 1900; 704 else 705 year += 2000; 706 } else if (tag == ASN1_GENTIM) { 707 /* GenTime: YYYYMMDDHHMMSSZ */ 708 if (vlen != 15) 709 goto unsupported_time; 710 year = DD2bin(p) * 100 + DD2bin(p); 711 if (year >= 1950 && year <= 2049) 712 goto invalid_time; 713 } else { 714 goto unsupported_time; 715 } 716 717 mon = DD2bin(p); 718 day = DD2bin(p); 719 hour = DD2bin(p); 720 min = DD2bin(p); 721 sec = DD2bin(p); 722 723 if (*p != 'Z') 724 goto unsupported_time; 725 726 if (year < 1970 || 727 mon < 1 || mon > 12) 728 goto invalid_time; 729 730 mon_len = month_lengths[mon - 1]; 731 if (mon == 2) { 732 if (year % 4 == 0) { 733 mon_len = 29; 734 if (year % 100 == 0) { 735 mon_len = 28; 736 if (year % 400 == 0) 737 mon_len = 29; 738 } 739 } 740 } 741 742 if (day < 1 || day > mon_len || 743 hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */ 744 min > 59 || 745 sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */ 746 goto invalid_time; 747 748 *_t = mktime64(year, mon, day, hour, min, sec); 749 return 0; 750 751 unsupported_time: 752 pr_debug("Got unsupported time [tag %02x]: '%*phN'\n", 753 tag, (int)vlen, value); 754 return -EBADMSG; 755 invalid_time: 756 pr_debug("Got invalid time [tag %02x]: '%*phN'\n", 757 tag, (int)vlen, value); 758 return -EBADMSG; 759 } 760 EXPORT_SYMBOL_GPL(x509_decode_time); 761 762 int x509_note_not_before(void *context, size_t hdrlen, 763 unsigned char tag, 764 const void *value, size_t vlen) 765 { 766 struct x509_parse_context *ctx = context; 767 return x509_decode_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen); 768 } 769 770 int x509_note_not_after(void *context, size_t hdrlen, 771 unsigned char tag, 772 const void *value, size_t vlen) 773 { 774 struct x509_parse_context *ctx = context; 775 return x509_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen); 776 } 777 778 /* 779 * Note a key identifier-based AuthorityKeyIdentifier 780 */ 781 int x509_akid_note_kid(void *context, size_t hdrlen, 782 unsigned char tag, 783 const void *value, size_t vlen) 784 { 785 struct x509_parse_context *ctx = context; 786 struct asymmetric_key_id *kid; 787 788 pr_debug("AKID: keyid: %*phN\n", (int)vlen, value); 789 790 if (ctx->cert->sig->auth_ids[1]) 791 return 0; 792 793 kid = asymmetric_key_generate_id(value, vlen, "", 0); 794 if (IS_ERR(kid)) 795 return PTR_ERR(kid); 796 pr_debug("authkeyid %*phN\n", kid->len, kid->data); 797 ctx->cert->sig->auth_ids[1] = kid; 798 return 0; 799 } 800 801 /* 802 * Note a directoryName in an AuthorityKeyIdentifier 803 */ 804 int x509_akid_note_name(void *context, size_t hdrlen, 805 unsigned char tag, 806 const void *value, size_t vlen) 807 { 808 struct x509_parse_context *ctx = context; 809 810 pr_debug("AKID: name: %*phN\n", (int)vlen, value); 811 812 ctx->akid_raw_issuer = value; 813 ctx->akid_raw_issuer_size = vlen; 814 return 0; 815 } 816 817 /* 818 * Note a serial number in an AuthorityKeyIdentifier 819 */ 820 int x509_akid_note_serial(void *context, size_t hdrlen, 821 unsigned char tag, 822 const void *value, size_t vlen) 823 { 824 struct x509_parse_context *ctx = context; 825 struct asymmetric_key_id *kid; 826 827 pr_debug("AKID: serial: %*phN\n", (int)vlen, value); 828 829 if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0]) 830 return 0; 831 832 kid = asymmetric_key_generate_id(value, 833 vlen, 834 ctx->akid_raw_issuer, 835 ctx->akid_raw_issuer_size); 836 if (IS_ERR(kid)) 837 return PTR_ERR(kid); 838 839 pr_debug("authkeyid %*phN\n", kid->len, kid->data); 840 ctx->cert->sig->auth_ids[0] = kid; 841 return 0; 842 } 843