1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* PKCS#7 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) "PKCS7: "fmt 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/export.h> 12 #include <linux/slab.h> 13 #include <linux/err.h> 14 #include <linux/oid_registry.h> 15 #include <crypto/public_key.h> 16 #include "pkcs7_parser.h" 17 #include "pkcs7.asn1.h" 18 19 MODULE_DESCRIPTION("PKCS#7 parser"); 20 MODULE_AUTHOR("Red Hat, Inc."); 21 MODULE_LICENSE("GPL"); 22 23 struct pkcs7_parse_context { 24 struct pkcs7_message *msg; /* Message being constructed */ 25 struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */ 26 struct pkcs7_signed_info **ppsinfo; 27 struct x509_certificate *certs; /* Certificate cache */ 28 struct x509_certificate **ppcerts; 29 unsigned long data; /* Start of data */ 30 enum OID last_oid; /* Last OID encountered */ 31 unsigned x509_index; 32 unsigned sinfo_index; 33 const void *raw_serial; 34 unsigned raw_serial_size; 35 unsigned raw_issuer_size; 36 const void *raw_issuer; 37 const void *raw_skid; 38 unsigned raw_skid_size; 39 bool expect_skid; 40 }; 41 42 /* 43 * Free a signed information block. 44 */ 45 static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo) 46 { 47 if (sinfo) { 48 public_key_signature_free(sinfo->sig); 49 kfree(sinfo); 50 } 51 } 52 53 /** 54 * pkcs7_free_message - Free a PKCS#7 message 55 * @pkcs7: The PKCS#7 message to free 56 */ 57 void pkcs7_free_message(struct pkcs7_message *pkcs7) 58 { 59 struct x509_certificate *cert; 60 struct pkcs7_signed_info *sinfo; 61 62 if (pkcs7) { 63 while (pkcs7->certs) { 64 cert = pkcs7->certs; 65 pkcs7->certs = cert->next; 66 x509_free_certificate(cert); 67 } 68 while (pkcs7->crl) { 69 cert = pkcs7->crl; 70 pkcs7->crl = cert->next; 71 x509_free_certificate(cert); 72 } 73 while (pkcs7->signed_infos) { 74 sinfo = pkcs7->signed_infos; 75 pkcs7->signed_infos = sinfo->next; 76 pkcs7_free_signed_info(sinfo); 77 } 78 kfree(pkcs7); 79 } 80 } 81 EXPORT_SYMBOL_GPL(pkcs7_free_message); 82 83 /* 84 * Check authenticatedAttributes are provided or not provided consistently. 85 */ 86 static int pkcs7_check_authattrs(struct pkcs7_message *msg) 87 { 88 struct pkcs7_signed_info *sinfo; 89 bool want = false; 90 91 sinfo = msg->signed_infos; 92 if (!sinfo) 93 goto inconsistent; 94 95 if (sinfo->authattrs) { 96 want = true; 97 msg->have_authattrs = true; 98 } 99 100 for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next) 101 if (!!sinfo->authattrs != want) 102 goto inconsistent; 103 return 0; 104 105 inconsistent: 106 pr_warn("Inconsistently supplied authAttrs\n"); 107 return -EINVAL; 108 } 109 110 /** 111 * pkcs7_parse_message - Parse a PKCS#7 message 112 * @data: The raw binary ASN.1 encoded message to be parsed 113 * @datalen: The size of the encoded message 114 */ 115 struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) 116 { 117 struct pkcs7_parse_context *ctx; 118 struct pkcs7_message *msg = ERR_PTR(-ENOMEM); 119 int ret; 120 121 ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL); 122 if (!ctx) 123 goto out_no_ctx; 124 ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL); 125 if (!ctx->msg) 126 goto out_no_msg; 127 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); 128 if (!ctx->sinfo) 129 goto out_no_sinfo; 130 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature), 131 GFP_KERNEL); 132 if (!ctx->sinfo->sig) 133 goto out_no_sig; 134 135 ctx->data = (unsigned long)data; 136 ctx->ppcerts = &ctx->certs; 137 ctx->ppsinfo = &ctx->msg->signed_infos; 138 139 /* Attempt to decode the signature */ 140 ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen); 141 if (ret < 0) { 142 msg = ERR_PTR(ret); 143 goto out; 144 } 145 146 ret = pkcs7_check_authattrs(ctx->msg); 147 if (ret < 0) { 148 msg = ERR_PTR(ret); 149 goto out; 150 } 151 152 msg = ctx->msg; 153 ctx->msg = NULL; 154 155 out: 156 while (ctx->certs) { 157 struct x509_certificate *cert = ctx->certs; 158 ctx->certs = cert->next; 159 x509_free_certificate(cert); 160 } 161 out_no_sig: 162 pkcs7_free_signed_info(ctx->sinfo); 163 out_no_sinfo: 164 pkcs7_free_message(ctx->msg); 165 out_no_msg: 166 kfree(ctx); 167 out_no_ctx: 168 return msg; 169 } 170 EXPORT_SYMBOL_GPL(pkcs7_parse_message); 171 172 /** 173 * pkcs7_get_content_data - Get access to the PKCS#7 content 174 * @pkcs7: The preparsed PKCS#7 message to access 175 * @_data: Place to return a pointer to the data 176 * @_data_len: Place to return the data length 177 * @_headerlen: Size of ASN.1 header not included in _data 178 * 179 * Get access to the data content of the PKCS#7 message. The size of the 180 * header of the ASN.1 object that contains it is also provided and can be used 181 * to adjust *_data and *_data_len to get the entire object. 182 * 183 * Returns -ENODATA if the data object was missing from the message. 184 */ 185 int pkcs7_get_content_data(const struct pkcs7_message *pkcs7, 186 const void **_data, size_t *_data_len, 187 size_t *_headerlen) 188 { 189 if (!pkcs7->data) 190 return -ENODATA; 191 192 *_data = pkcs7->data; 193 *_data_len = pkcs7->data_len; 194 if (_headerlen) 195 *_headerlen = pkcs7->data_hdrlen; 196 return 0; 197 } 198 EXPORT_SYMBOL_GPL(pkcs7_get_content_data); 199 200 /* 201 * Note an OID when we find one for later processing when we know how 202 * to interpret it. 203 */ 204 int pkcs7_note_OID(void *context, size_t hdrlen, 205 unsigned char tag, 206 const void *value, size_t vlen) 207 { 208 struct pkcs7_parse_context *ctx = context; 209 210 ctx->last_oid = look_up_OID(value, vlen); 211 if (ctx->last_oid == OID__NR) { 212 char buffer[50]; 213 sprint_oid(value, vlen, buffer, sizeof(buffer)); 214 printk("PKCS7: Unknown OID: [%lu] %s\n", 215 (unsigned long)value - ctx->data, buffer); 216 } 217 return 0; 218 } 219 220 /* 221 * Note the digest algorithm for the signature. 222 */ 223 int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen, 224 unsigned char tag, 225 const void *value, size_t vlen) 226 { 227 struct pkcs7_parse_context *ctx = context; 228 229 switch (ctx->last_oid) { 230 case OID_sha256: 231 ctx->sinfo->sig->hash_algo = "sha256"; 232 break; 233 case OID_sha384: 234 ctx->sinfo->sig->hash_algo = "sha384"; 235 break; 236 case OID_sha512: 237 ctx->sinfo->sig->hash_algo = "sha512"; 238 break; 239 case OID_sha224: 240 ctx->sinfo->sig->hash_algo = "sha224"; 241 break; 242 case OID_sm3: 243 ctx->sinfo->sig->hash_algo = "sm3"; 244 break; 245 case OID_gost2012Digest256: 246 ctx->sinfo->sig->hash_algo = "streebog256"; 247 break; 248 case OID_gost2012Digest512: 249 ctx->sinfo->sig->hash_algo = "streebog512"; 250 break; 251 case OID_sha3_256: 252 ctx->sinfo->sig->hash_algo = "sha3-256"; 253 break; 254 case OID_sha3_384: 255 ctx->sinfo->sig->hash_algo = "sha3-384"; 256 break; 257 case OID_sha3_512: 258 ctx->sinfo->sig->hash_algo = "sha3-512"; 259 break; 260 default: 261 printk("Unsupported digest algo: %u\n", ctx->last_oid); 262 return -ENOPKG; 263 } 264 return 0; 265 } 266 267 /* 268 * Note the public key algorithm for the signature. 269 */ 270 int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen, 271 unsigned char tag, 272 const void *value, size_t vlen) 273 { 274 struct pkcs7_parse_context *ctx = context; 275 276 switch (ctx->last_oid) { 277 case OID_rsaEncryption: 278 ctx->sinfo->sig->pkey_algo = "rsa"; 279 ctx->sinfo->sig->encoding = "pkcs1"; 280 break; 281 case OID_id_ecdsa_with_sha224: 282 case OID_id_ecdsa_with_sha256: 283 case OID_id_ecdsa_with_sha384: 284 case OID_id_ecdsa_with_sha512: 285 case OID_id_ecdsa_with_sha3_256: 286 case OID_id_ecdsa_with_sha3_384: 287 case OID_id_ecdsa_with_sha3_512: 288 ctx->sinfo->sig->pkey_algo = "ecdsa"; 289 ctx->sinfo->sig->encoding = "x962"; 290 break; 291 case OID_SM2_with_SM3: 292 ctx->sinfo->sig->pkey_algo = "sm2"; 293 ctx->sinfo->sig->encoding = "raw"; 294 break; 295 case OID_gost2012PKey256: 296 case OID_gost2012PKey512: 297 ctx->sinfo->sig->pkey_algo = "ecrdsa"; 298 ctx->sinfo->sig->encoding = "raw"; 299 break; 300 default: 301 printk("Unsupported pkey algo: %u\n", ctx->last_oid); 302 return -ENOPKG; 303 } 304 return 0; 305 } 306 307 /* 308 * We only support signed data [RFC2315 sec 9]. 309 */ 310 int pkcs7_check_content_type(void *context, size_t hdrlen, 311 unsigned char tag, 312 const void *value, size_t vlen) 313 { 314 struct pkcs7_parse_context *ctx = context; 315 316 if (ctx->last_oid != OID_signed_data) { 317 pr_warn("Only support pkcs7_signedData type\n"); 318 return -EINVAL; 319 } 320 321 return 0; 322 } 323 324 /* 325 * Note the SignedData version 326 */ 327 int pkcs7_note_signeddata_version(void *context, size_t hdrlen, 328 unsigned char tag, 329 const void *value, size_t vlen) 330 { 331 struct pkcs7_parse_context *ctx = context; 332 unsigned version; 333 334 if (vlen != 1) 335 goto unsupported; 336 337 ctx->msg->version = version = *(const u8 *)value; 338 switch (version) { 339 case 1: 340 /* PKCS#7 SignedData [RFC2315 sec 9.1] 341 * CMS ver 1 SignedData [RFC5652 sec 5.1] 342 */ 343 break; 344 case 3: 345 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */ 346 break; 347 default: 348 goto unsupported; 349 } 350 351 return 0; 352 353 unsupported: 354 pr_warn("Unsupported SignedData version\n"); 355 return -EINVAL; 356 } 357 358 /* 359 * Note the SignerInfo version 360 */ 361 int pkcs7_note_signerinfo_version(void *context, size_t hdrlen, 362 unsigned char tag, 363 const void *value, size_t vlen) 364 { 365 struct pkcs7_parse_context *ctx = context; 366 unsigned version; 367 368 if (vlen != 1) 369 goto unsupported; 370 371 version = *(const u8 *)value; 372 switch (version) { 373 case 1: 374 /* PKCS#7 SignerInfo [RFC2315 sec 9.2] 375 * CMS ver 1 SignerInfo [RFC5652 sec 5.3] 376 */ 377 if (ctx->msg->version != 1) 378 goto version_mismatch; 379 ctx->expect_skid = false; 380 break; 381 case 3: 382 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */ 383 if (ctx->msg->version == 1) 384 goto version_mismatch; 385 ctx->expect_skid = true; 386 break; 387 default: 388 goto unsupported; 389 } 390 391 return 0; 392 393 unsupported: 394 pr_warn("Unsupported SignerInfo version\n"); 395 return -EINVAL; 396 version_mismatch: 397 pr_warn("SignedData-SignerInfo version mismatch\n"); 398 return -EBADMSG; 399 } 400 401 /* 402 * Extract a certificate and store it in the context. 403 */ 404 int pkcs7_extract_cert(void *context, size_t hdrlen, 405 unsigned char tag, 406 const void *value, size_t vlen) 407 { 408 struct pkcs7_parse_context *ctx = context; 409 struct x509_certificate *x509; 410 411 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) { 412 pr_debug("Cert began with tag %02x at %lu\n", 413 tag, (unsigned long)ctx - ctx->data); 414 return -EBADMSG; 415 } 416 417 /* We have to correct for the header so that the X.509 parser can start 418 * from the beginning. Note that since X.509 stipulates DER, there 419 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which 420 * stipulates BER). 421 */ 422 value -= hdrlen; 423 vlen += hdrlen; 424 425 if (((u8*)value)[1] == 0x80) 426 vlen += 2; /* Indefinite length - there should be an EOC */ 427 428 x509 = x509_cert_parse(value, vlen); 429 if (IS_ERR(x509)) 430 return PTR_ERR(x509); 431 432 x509->index = ++ctx->x509_index; 433 pr_debug("Got cert %u for %s\n", x509->index, x509->subject); 434 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data); 435 436 *ctx->ppcerts = x509; 437 ctx->ppcerts = &x509->next; 438 return 0; 439 } 440 441 /* 442 * Save the certificate list 443 */ 444 int pkcs7_note_certificate_list(void *context, size_t hdrlen, 445 unsigned char tag, 446 const void *value, size_t vlen) 447 { 448 struct pkcs7_parse_context *ctx = context; 449 450 pr_devel("Got cert list (%02x)\n", tag); 451 452 *ctx->ppcerts = ctx->msg->certs; 453 ctx->msg->certs = ctx->certs; 454 ctx->certs = NULL; 455 ctx->ppcerts = &ctx->certs; 456 return 0; 457 } 458 459 /* 460 * Note the content type. 461 */ 462 int pkcs7_note_content(void *context, size_t hdrlen, 463 unsigned char tag, 464 const void *value, size_t vlen) 465 { 466 struct pkcs7_parse_context *ctx = context; 467 468 if (ctx->last_oid != OID_data && 469 ctx->last_oid != OID_msIndirectData) { 470 pr_warn("Unsupported data type %d\n", ctx->last_oid); 471 return -EINVAL; 472 } 473 474 ctx->msg->data_type = ctx->last_oid; 475 return 0; 476 } 477 478 /* 479 * Extract the data from the message and store that and its content type OID in 480 * the context. 481 */ 482 int pkcs7_note_data(void *context, size_t hdrlen, 483 unsigned char tag, 484 const void *value, size_t vlen) 485 { 486 struct pkcs7_parse_context *ctx = context; 487 488 pr_debug("Got data\n"); 489 490 ctx->msg->data = value; 491 ctx->msg->data_len = vlen; 492 ctx->msg->data_hdrlen = hdrlen; 493 return 0; 494 } 495 496 /* 497 * Parse authenticated attributes. 498 */ 499 int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, 500 unsigned char tag, 501 const void *value, size_t vlen) 502 { 503 struct pkcs7_parse_context *ctx = context; 504 struct pkcs7_signed_info *sinfo = ctx->sinfo; 505 enum OID content_type; 506 507 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 508 509 switch (ctx->last_oid) { 510 case OID_contentType: 511 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set)) 512 goto repeated; 513 content_type = look_up_OID(value, vlen); 514 if (content_type != ctx->msg->data_type) { 515 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n", 516 ctx->msg->data_type, sinfo->index, 517 content_type); 518 return -EBADMSG; 519 } 520 return 0; 521 522 case OID_signingTime: 523 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set)) 524 goto repeated; 525 /* Should we check that the signing time is consistent 526 * with the signer's X.509 cert? 527 */ 528 return x509_decode_time(&sinfo->signing_time, 529 hdrlen, tag, value, vlen); 530 531 case OID_messageDigest: 532 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set)) 533 goto repeated; 534 if (tag != ASN1_OTS) 535 return -EBADMSG; 536 sinfo->msgdigest = value; 537 sinfo->msgdigest_len = vlen; 538 return 0; 539 540 case OID_smimeCapabilites: 541 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set)) 542 goto repeated; 543 if (ctx->msg->data_type != OID_msIndirectData) { 544 pr_warn("S/MIME Caps only allowed with Authenticode\n"); 545 return -EKEYREJECTED; 546 } 547 return 0; 548 549 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE 550 * char URLs and cont[1] 8-bit char URLs. 551 * 552 * Microsoft StatementType seems to contain a list of OIDs that 553 * are also used as extendedKeyUsage types in X.509 certs. 554 */ 555 case OID_msSpOpusInfo: 556 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) 557 goto repeated; 558 goto authenticode_check; 559 case OID_msStatementType: 560 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set)) 561 goto repeated; 562 authenticode_check: 563 if (ctx->msg->data_type != OID_msIndirectData) { 564 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n"); 565 return -EKEYREJECTED; 566 } 567 /* I'm not sure how to validate these */ 568 return 0; 569 default: 570 return 0; 571 } 572 573 repeated: 574 /* We permit max one item per AuthenticatedAttribute and no repeats */ 575 pr_warn("Repeated/multivalue AuthAttrs not permitted\n"); 576 return -EKEYREJECTED; 577 } 578 579 /* 580 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3] 581 */ 582 int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, 583 unsigned char tag, 584 const void *value, size_t vlen) 585 { 586 struct pkcs7_parse_context *ctx = context; 587 struct pkcs7_signed_info *sinfo = ctx->sinfo; 588 589 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) || 590 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) { 591 pr_warn("Missing required AuthAttr\n"); 592 return -EBADMSG; 593 } 594 595 if (ctx->msg->data_type != OID_msIndirectData && 596 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) { 597 pr_warn("Unexpected Authenticode AuthAttr\n"); 598 return -EBADMSG; 599 } 600 601 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */ 602 sinfo->authattrs = value - (hdrlen - 1); 603 sinfo->authattrs_len = vlen + (hdrlen - 1); 604 return 0; 605 } 606 607 /* 608 * Note the issuing certificate serial number 609 */ 610 int pkcs7_sig_note_serial(void *context, size_t hdrlen, 611 unsigned char tag, 612 const void *value, size_t vlen) 613 { 614 struct pkcs7_parse_context *ctx = context; 615 ctx->raw_serial = value; 616 ctx->raw_serial_size = vlen; 617 return 0; 618 } 619 620 /* 621 * Note the issuer's name 622 */ 623 int pkcs7_sig_note_issuer(void *context, size_t hdrlen, 624 unsigned char tag, 625 const void *value, size_t vlen) 626 { 627 struct pkcs7_parse_context *ctx = context; 628 ctx->raw_issuer = value; 629 ctx->raw_issuer_size = vlen; 630 return 0; 631 } 632 633 /* 634 * Note the issuing cert's subjectKeyIdentifier 635 */ 636 int pkcs7_sig_note_skid(void *context, size_t hdrlen, 637 unsigned char tag, 638 const void *value, size_t vlen) 639 { 640 struct pkcs7_parse_context *ctx = context; 641 642 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 643 644 ctx->raw_skid = value; 645 ctx->raw_skid_size = vlen; 646 return 0; 647 } 648 649 /* 650 * Note the signature data 651 */ 652 int pkcs7_sig_note_signature(void *context, size_t hdrlen, 653 unsigned char tag, 654 const void *value, size_t vlen) 655 { 656 struct pkcs7_parse_context *ctx = context; 657 658 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL); 659 if (!ctx->sinfo->sig->s) 660 return -ENOMEM; 661 662 ctx->sinfo->sig->s_size = vlen; 663 return 0; 664 } 665 666 /* 667 * Note a signature information block 668 */ 669 int pkcs7_note_signed_info(void *context, size_t hdrlen, 670 unsigned char tag, 671 const void *value, size_t vlen) 672 { 673 struct pkcs7_parse_context *ctx = context; 674 struct pkcs7_signed_info *sinfo = ctx->sinfo; 675 struct asymmetric_key_id *kid; 676 677 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) { 678 pr_warn("Authenticode requires AuthAttrs\n"); 679 return -EBADMSG; 680 } 681 682 /* Generate cert issuer + serial number key ID */ 683 if (!ctx->expect_skid) { 684 kid = asymmetric_key_generate_id(ctx->raw_serial, 685 ctx->raw_serial_size, 686 ctx->raw_issuer, 687 ctx->raw_issuer_size); 688 } else { 689 kid = asymmetric_key_generate_id(ctx->raw_skid, 690 ctx->raw_skid_size, 691 "", 0); 692 } 693 if (IS_ERR(kid)) 694 return PTR_ERR(kid); 695 696 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data); 697 698 sinfo->sig->auth_ids[0] = kid; 699 sinfo->index = ++ctx->sinfo_index; 700 *ctx->ppsinfo = sinfo; 701 ctx->ppsinfo = &sinfo->next; 702 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); 703 if (!ctx->sinfo) 704 return -ENOMEM; 705 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature), 706 GFP_KERNEL); 707 if (!ctx->sinfo->sig) 708 return -ENOMEM; 709 return 0; 710 } 711