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_md4: 231 ctx->sinfo->sig->hash_algo = "md4"; 232 break; 233 case OID_md5: 234 ctx->sinfo->sig->hash_algo = "md5"; 235 break; 236 case OID_sha1: 237 ctx->sinfo->sig->hash_algo = "sha1"; 238 break; 239 case OID_sha256: 240 ctx->sinfo->sig->hash_algo = "sha256"; 241 break; 242 case OID_sha384: 243 ctx->sinfo->sig->hash_algo = "sha384"; 244 break; 245 case OID_sha512: 246 ctx->sinfo->sig->hash_algo = "sha512"; 247 break; 248 case OID_sha224: 249 ctx->sinfo->sig->hash_algo = "sha224"; 250 break; 251 case OID_sm3: 252 ctx->sinfo->sig->hash_algo = "sm3"; 253 break; 254 case OID_gost2012Digest256: 255 ctx->sinfo->sig->hash_algo = "streebog256"; 256 break; 257 case OID_gost2012Digest512: 258 ctx->sinfo->sig->hash_algo = "streebog512"; 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_sha1: 282 case OID_id_ecdsa_with_sha224: 283 case OID_id_ecdsa_with_sha256: 284 case OID_id_ecdsa_with_sha384: 285 case OID_id_ecdsa_with_sha512: 286 ctx->sinfo->sig->pkey_algo = "ecdsa"; 287 ctx->sinfo->sig->encoding = "x962"; 288 break; 289 case OID_SM2_with_SM3: 290 ctx->sinfo->sig->pkey_algo = "sm2"; 291 ctx->sinfo->sig->encoding = "raw"; 292 break; 293 case OID_gost2012PKey256: 294 case OID_gost2012PKey512: 295 ctx->sinfo->sig->pkey_algo = "ecrdsa"; 296 ctx->sinfo->sig->encoding = "raw"; 297 break; 298 default: 299 printk("Unsupported pkey algo: %u\n", ctx->last_oid); 300 return -ENOPKG; 301 } 302 return 0; 303 } 304 305 /* 306 * We only support signed data [RFC2315 sec 9]. 307 */ 308 int pkcs7_check_content_type(void *context, size_t hdrlen, 309 unsigned char tag, 310 const void *value, size_t vlen) 311 { 312 struct pkcs7_parse_context *ctx = context; 313 314 if (ctx->last_oid != OID_signed_data) { 315 pr_warn("Only support pkcs7_signedData type\n"); 316 return -EINVAL; 317 } 318 319 return 0; 320 } 321 322 /* 323 * Note the SignedData version 324 */ 325 int pkcs7_note_signeddata_version(void *context, size_t hdrlen, 326 unsigned char tag, 327 const void *value, size_t vlen) 328 { 329 struct pkcs7_parse_context *ctx = context; 330 unsigned version; 331 332 if (vlen != 1) 333 goto unsupported; 334 335 ctx->msg->version = version = *(const u8 *)value; 336 switch (version) { 337 case 1: 338 /* PKCS#7 SignedData [RFC2315 sec 9.1] 339 * CMS ver 1 SignedData [RFC5652 sec 5.1] 340 */ 341 break; 342 case 3: 343 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */ 344 break; 345 default: 346 goto unsupported; 347 } 348 349 return 0; 350 351 unsupported: 352 pr_warn("Unsupported SignedData version\n"); 353 return -EINVAL; 354 } 355 356 /* 357 * Note the SignerInfo version 358 */ 359 int pkcs7_note_signerinfo_version(void *context, size_t hdrlen, 360 unsigned char tag, 361 const void *value, size_t vlen) 362 { 363 struct pkcs7_parse_context *ctx = context; 364 unsigned version; 365 366 if (vlen != 1) 367 goto unsupported; 368 369 version = *(const u8 *)value; 370 switch (version) { 371 case 1: 372 /* PKCS#7 SignerInfo [RFC2315 sec 9.2] 373 * CMS ver 1 SignerInfo [RFC5652 sec 5.3] 374 */ 375 if (ctx->msg->version != 1) 376 goto version_mismatch; 377 ctx->expect_skid = false; 378 break; 379 case 3: 380 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */ 381 if (ctx->msg->version == 1) 382 goto version_mismatch; 383 ctx->expect_skid = true; 384 break; 385 default: 386 goto unsupported; 387 } 388 389 return 0; 390 391 unsupported: 392 pr_warn("Unsupported SignerInfo version\n"); 393 return -EINVAL; 394 version_mismatch: 395 pr_warn("SignedData-SignerInfo version mismatch\n"); 396 return -EBADMSG; 397 } 398 399 /* 400 * Extract a certificate and store it in the context. 401 */ 402 int pkcs7_extract_cert(void *context, size_t hdrlen, 403 unsigned char tag, 404 const void *value, size_t vlen) 405 { 406 struct pkcs7_parse_context *ctx = context; 407 struct x509_certificate *x509; 408 409 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) { 410 pr_debug("Cert began with tag %02x at %lu\n", 411 tag, (unsigned long)ctx - ctx->data); 412 return -EBADMSG; 413 } 414 415 /* We have to correct for the header so that the X.509 parser can start 416 * from the beginning. Note that since X.509 stipulates DER, there 417 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which 418 * stipulates BER). 419 */ 420 value -= hdrlen; 421 vlen += hdrlen; 422 423 if (((u8*)value)[1] == 0x80) 424 vlen += 2; /* Indefinite length - there should be an EOC */ 425 426 x509 = x509_cert_parse(value, vlen); 427 if (IS_ERR(x509)) 428 return PTR_ERR(x509); 429 430 x509->index = ++ctx->x509_index; 431 pr_debug("Got cert %u for %s\n", x509->index, x509->subject); 432 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data); 433 434 *ctx->ppcerts = x509; 435 ctx->ppcerts = &x509->next; 436 return 0; 437 } 438 439 /* 440 * Save the certificate list 441 */ 442 int pkcs7_note_certificate_list(void *context, size_t hdrlen, 443 unsigned char tag, 444 const void *value, size_t vlen) 445 { 446 struct pkcs7_parse_context *ctx = context; 447 448 pr_devel("Got cert list (%02x)\n", tag); 449 450 *ctx->ppcerts = ctx->msg->certs; 451 ctx->msg->certs = ctx->certs; 452 ctx->certs = NULL; 453 ctx->ppcerts = &ctx->certs; 454 return 0; 455 } 456 457 /* 458 * Note the content type. 459 */ 460 int pkcs7_note_content(void *context, size_t hdrlen, 461 unsigned char tag, 462 const void *value, size_t vlen) 463 { 464 struct pkcs7_parse_context *ctx = context; 465 466 if (ctx->last_oid != OID_data && 467 ctx->last_oid != OID_msIndirectData) { 468 pr_warn("Unsupported data type %d\n", ctx->last_oid); 469 return -EINVAL; 470 } 471 472 ctx->msg->data_type = ctx->last_oid; 473 return 0; 474 } 475 476 /* 477 * Extract the data from the message and store that and its content type OID in 478 * the context. 479 */ 480 int pkcs7_note_data(void *context, size_t hdrlen, 481 unsigned char tag, 482 const void *value, size_t vlen) 483 { 484 struct pkcs7_parse_context *ctx = context; 485 486 pr_debug("Got data\n"); 487 488 ctx->msg->data = value; 489 ctx->msg->data_len = vlen; 490 ctx->msg->data_hdrlen = hdrlen; 491 return 0; 492 } 493 494 /* 495 * Parse authenticated attributes. 496 */ 497 int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, 498 unsigned char tag, 499 const void *value, size_t vlen) 500 { 501 struct pkcs7_parse_context *ctx = context; 502 struct pkcs7_signed_info *sinfo = ctx->sinfo; 503 enum OID content_type; 504 505 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 506 507 switch (ctx->last_oid) { 508 case OID_contentType: 509 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set)) 510 goto repeated; 511 content_type = look_up_OID(value, vlen); 512 if (content_type != ctx->msg->data_type) { 513 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n", 514 ctx->msg->data_type, sinfo->index, 515 content_type); 516 return -EBADMSG; 517 } 518 return 0; 519 520 case OID_signingTime: 521 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set)) 522 goto repeated; 523 /* Should we check that the signing time is consistent 524 * with the signer's X.509 cert? 525 */ 526 return x509_decode_time(&sinfo->signing_time, 527 hdrlen, tag, value, vlen); 528 529 case OID_messageDigest: 530 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set)) 531 goto repeated; 532 if (tag != ASN1_OTS) 533 return -EBADMSG; 534 sinfo->msgdigest = value; 535 sinfo->msgdigest_len = vlen; 536 return 0; 537 538 case OID_smimeCapabilites: 539 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set)) 540 goto repeated; 541 if (ctx->msg->data_type != OID_msIndirectData) { 542 pr_warn("S/MIME Caps only allowed with Authenticode\n"); 543 return -EKEYREJECTED; 544 } 545 return 0; 546 547 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE 548 * char URLs and cont[1] 8-bit char URLs. 549 * 550 * Microsoft StatementType seems to contain a list of OIDs that 551 * are also used as extendedKeyUsage types in X.509 certs. 552 */ 553 case OID_msSpOpusInfo: 554 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) 555 goto repeated; 556 goto authenticode_check; 557 case OID_msStatementType: 558 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set)) 559 goto repeated; 560 authenticode_check: 561 if (ctx->msg->data_type != OID_msIndirectData) { 562 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n"); 563 return -EKEYREJECTED; 564 } 565 /* I'm not sure how to validate these */ 566 return 0; 567 default: 568 return 0; 569 } 570 571 repeated: 572 /* We permit max one item per AuthenticatedAttribute and no repeats */ 573 pr_warn("Repeated/multivalue AuthAttrs not permitted\n"); 574 return -EKEYREJECTED; 575 } 576 577 /* 578 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3] 579 */ 580 int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, 581 unsigned char tag, 582 const void *value, size_t vlen) 583 { 584 struct pkcs7_parse_context *ctx = context; 585 struct pkcs7_signed_info *sinfo = ctx->sinfo; 586 587 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) || 588 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) { 589 pr_warn("Missing required AuthAttr\n"); 590 return -EBADMSG; 591 } 592 593 if (ctx->msg->data_type != OID_msIndirectData && 594 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) { 595 pr_warn("Unexpected Authenticode AuthAttr\n"); 596 return -EBADMSG; 597 } 598 599 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */ 600 sinfo->authattrs = value - (hdrlen - 1); 601 sinfo->authattrs_len = vlen + (hdrlen - 1); 602 return 0; 603 } 604 605 /* 606 * Note the issuing certificate serial number 607 */ 608 int pkcs7_sig_note_serial(void *context, size_t hdrlen, 609 unsigned char tag, 610 const void *value, size_t vlen) 611 { 612 struct pkcs7_parse_context *ctx = context; 613 ctx->raw_serial = value; 614 ctx->raw_serial_size = vlen; 615 return 0; 616 } 617 618 /* 619 * Note the issuer's name 620 */ 621 int pkcs7_sig_note_issuer(void *context, size_t hdrlen, 622 unsigned char tag, 623 const void *value, size_t vlen) 624 { 625 struct pkcs7_parse_context *ctx = context; 626 ctx->raw_issuer = value; 627 ctx->raw_issuer_size = vlen; 628 return 0; 629 } 630 631 /* 632 * Note the issuing cert's subjectKeyIdentifier 633 */ 634 int pkcs7_sig_note_skid(void *context, size_t hdrlen, 635 unsigned char tag, 636 const void *value, size_t vlen) 637 { 638 struct pkcs7_parse_context *ctx = context; 639 640 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 641 642 ctx->raw_skid = value; 643 ctx->raw_skid_size = vlen; 644 return 0; 645 } 646 647 /* 648 * Note the signature data 649 */ 650 int pkcs7_sig_note_signature(void *context, size_t hdrlen, 651 unsigned char tag, 652 const void *value, size_t vlen) 653 { 654 struct pkcs7_parse_context *ctx = context; 655 656 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL); 657 if (!ctx->sinfo->sig->s) 658 return -ENOMEM; 659 660 ctx->sinfo->sig->s_size = vlen; 661 return 0; 662 } 663 664 /* 665 * Note a signature information block 666 */ 667 int pkcs7_note_signed_info(void *context, size_t hdrlen, 668 unsigned char tag, 669 const void *value, size_t vlen) 670 { 671 struct pkcs7_parse_context *ctx = context; 672 struct pkcs7_signed_info *sinfo = ctx->sinfo; 673 struct asymmetric_key_id *kid; 674 675 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) { 676 pr_warn("Authenticode requires AuthAttrs\n"); 677 return -EBADMSG; 678 } 679 680 /* Generate cert issuer + serial number key ID */ 681 if (!ctx->expect_skid) { 682 kid = asymmetric_key_generate_id(ctx->raw_serial, 683 ctx->raw_serial_size, 684 ctx->raw_issuer, 685 ctx->raw_issuer_size); 686 } else { 687 kid = asymmetric_key_generate_id(ctx->raw_skid, 688 ctx->raw_skid_size, 689 "", 0); 690 } 691 if (IS_ERR(kid)) 692 return PTR_ERR(kid); 693 694 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data); 695 696 sinfo->sig->auth_ids[0] = kid; 697 sinfo->index = ++ctx->sinfo_index; 698 *ctx->ppsinfo = sinfo; 699 ctx->ppsinfo = &sinfo->next; 700 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); 701 if (!ctx->sinfo) 702 return -ENOMEM; 703 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature), 704 GFP_KERNEL); 705 if (!ctx->sinfo->sig) 706 return -ENOMEM; 707 return 0; 708 } 709