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_sha1: 231 ctx->sinfo->sig->hash_algo = "sha1"; 232 break; 233 case OID_sha256: 234 ctx->sinfo->sig->hash_algo = "sha256"; 235 break; 236 case OID_sha384: 237 ctx->sinfo->sig->hash_algo = "sha384"; 238 break; 239 case OID_sha512: 240 ctx->sinfo->sig->hash_algo = "sha512"; 241 break; 242 case OID_sha224: 243 ctx->sinfo->sig->hash_algo = "sha224"; 244 break; 245 case OID_sm3: 246 ctx->sinfo->sig->hash_algo = "sm3"; 247 break; 248 case OID_gost2012Digest256: 249 ctx->sinfo->sig->hash_algo = "streebog256"; 250 break; 251 case OID_gost2012Digest512: 252 ctx->sinfo->sig->hash_algo = "streebog512"; 253 break; 254 default: 255 printk("Unsupported digest algo: %u\n", ctx->last_oid); 256 return -ENOPKG; 257 } 258 return 0; 259 } 260 261 /* 262 * Note the public key algorithm for the signature. 263 */ 264 int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen, 265 unsigned char tag, 266 const void *value, size_t vlen) 267 { 268 struct pkcs7_parse_context *ctx = context; 269 270 switch (ctx->last_oid) { 271 case OID_rsaEncryption: 272 ctx->sinfo->sig->pkey_algo = "rsa"; 273 ctx->sinfo->sig->encoding = "pkcs1"; 274 break; 275 case OID_id_ecdsa_with_sha1: 276 case OID_id_ecdsa_with_sha224: 277 case OID_id_ecdsa_with_sha256: 278 case OID_id_ecdsa_with_sha384: 279 case OID_id_ecdsa_with_sha512: 280 ctx->sinfo->sig->pkey_algo = "ecdsa"; 281 ctx->sinfo->sig->encoding = "x962"; 282 break; 283 case OID_SM2_with_SM3: 284 ctx->sinfo->sig->pkey_algo = "sm2"; 285 ctx->sinfo->sig->encoding = "raw"; 286 break; 287 case OID_gost2012PKey256: 288 case OID_gost2012PKey512: 289 ctx->sinfo->sig->pkey_algo = "ecrdsa"; 290 ctx->sinfo->sig->encoding = "raw"; 291 break; 292 default: 293 printk("Unsupported pkey algo: %u\n", ctx->last_oid); 294 return -ENOPKG; 295 } 296 return 0; 297 } 298 299 /* 300 * We only support signed data [RFC2315 sec 9]. 301 */ 302 int pkcs7_check_content_type(void *context, size_t hdrlen, 303 unsigned char tag, 304 const void *value, size_t vlen) 305 { 306 struct pkcs7_parse_context *ctx = context; 307 308 if (ctx->last_oid != OID_signed_data) { 309 pr_warn("Only support pkcs7_signedData type\n"); 310 return -EINVAL; 311 } 312 313 return 0; 314 } 315 316 /* 317 * Note the SignedData version 318 */ 319 int pkcs7_note_signeddata_version(void *context, size_t hdrlen, 320 unsigned char tag, 321 const void *value, size_t vlen) 322 { 323 struct pkcs7_parse_context *ctx = context; 324 unsigned version; 325 326 if (vlen != 1) 327 goto unsupported; 328 329 ctx->msg->version = version = *(const u8 *)value; 330 switch (version) { 331 case 1: 332 /* PKCS#7 SignedData [RFC2315 sec 9.1] 333 * CMS ver 1 SignedData [RFC5652 sec 5.1] 334 */ 335 break; 336 case 3: 337 /* CMS ver 3 SignedData [RFC2315 sec 5.1] */ 338 break; 339 default: 340 goto unsupported; 341 } 342 343 return 0; 344 345 unsupported: 346 pr_warn("Unsupported SignedData version\n"); 347 return -EINVAL; 348 } 349 350 /* 351 * Note the SignerInfo version 352 */ 353 int pkcs7_note_signerinfo_version(void *context, size_t hdrlen, 354 unsigned char tag, 355 const void *value, size_t vlen) 356 { 357 struct pkcs7_parse_context *ctx = context; 358 unsigned version; 359 360 if (vlen != 1) 361 goto unsupported; 362 363 version = *(const u8 *)value; 364 switch (version) { 365 case 1: 366 /* PKCS#7 SignerInfo [RFC2315 sec 9.2] 367 * CMS ver 1 SignerInfo [RFC5652 sec 5.3] 368 */ 369 if (ctx->msg->version != 1) 370 goto version_mismatch; 371 ctx->expect_skid = false; 372 break; 373 case 3: 374 /* CMS ver 3 SignerInfo [RFC2315 sec 5.3] */ 375 if (ctx->msg->version == 1) 376 goto version_mismatch; 377 ctx->expect_skid = true; 378 break; 379 default: 380 goto unsupported; 381 } 382 383 return 0; 384 385 unsupported: 386 pr_warn("Unsupported SignerInfo version\n"); 387 return -EINVAL; 388 version_mismatch: 389 pr_warn("SignedData-SignerInfo version mismatch\n"); 390 return -EBADMSG; 391 } 392 393 /* 394 * Extract a certificate and store it in the context. 395 */ 396 int pkcs7_extract_cert(void *context, size_t hdrlen, 397 unsigned char tag, 398 const void *value, size_t vlen) 399 { 400 struct pkcs7_parse_context *ctx = context; 401 struct x509_certificate *x509; 402 403 if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) { 404 pr_debug("Cert began with tag %02x at %lu\n", 405 tag, (unsigned long)ctx - ctx->data); 406 return -EBADMSG; 407 } 408 409 /* We have to correct for the header so that the X.509 parser can start 410 * from the beginning. Note that since X.509 stipulates DER, there 411 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which 412 * stipulates BER). 413 */ 414 value -= hdrlen; 415 vlen += hdrlen; 416 417 if (((u8*)value)[1] == 0x80) 418 vlen += 2; /* Indefinite length - there should be an EOC */ 419 420 x509 = x509_cert_parse(value, vlen); 421 if (IS_ERR(x509)) 422 return PTR_ERR(x509); 423 424 x509->index = ++ctx->x509_index; 425 pr_debug("Got cert %u for %s\n", x509->index, x509->subject); 426 pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data); 427 428 *ctx->ppcerts = x509; 429 ctx->ppcerts = &x509->next; 430 return 0; 431 } 432 433 /* 434 * Save the certificate list 435 */ 436 int pkcs7_note_certificate_list(void *context, size_t hdrlen, 437 unsigned char tag, 438 const void *value, size_t vlen) 439 { 440 struct pkcs7_parse_context *ctx = context; 441 442 pr_devel("Got cert list (%02x)\n", tag); 443 444 *ctx->ppcerts = ctx->msg->certs; 445 ctx->msg->certs = ctx->certs; 446 ctx->certs = NULL; 447 ctx->ppcerts = &ctx->certs; 448 return 0; 449 } 450 451 /* 452 * Note the content type. 453 */ 454 int pkcs7_note_content(void *context, size_t hdrlen, 455 unsigned char tag, 456 const void *value, size_t vlen) 457 { 458 struct pkcs7_parse_context *ctx = context; 459 460 if (ctx->last_oid != OID_data && 461 ctx->last_oid != OID_msIndirectData) { 462 pr_warn("Unsupported data type %d\n", ctx->last_oid); 463 return -EINVAL; 464 } 465 466 ctx->msg->data_type = ctx->last_oid; 467 return 0; 468 } 469 470 /* 471 * Extract the data from the message and store that and its content type OID in 472 * the context. 473 */ 474 int pkcs7_note_data(void *context, size_t hdrlen, 475 unsigned char tag, 476 const void *value, size_t vlen) 477 { 478 struct pkcs7_parse_context *ctx = context; 479 480 pr_debug("Got data\n"); 481 482 ctx->msg->data = value; 483 ctx->msg->data_len = vlen; 484 ctx->msg->data_hdrlen = hdrlen; 485 return 0; 486 } 487 488 /* 489 * Parse authenticated attributes. 490 */ 491 int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, 492 unsigned char tag, 493 const void *value, size_t vlen) 494 { 495 struct pkcs7_parse_context *ctx = context; 496 struct pkcs7_signed_info *sinfo = ctx->sinfo; 497 enum OID content_type; 498 499 pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 500 501 switch (ctx->last_oid) { 502 case OID_contentType: 503 if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set)) 504 goto repeated; 505 content_type = look_up_OID(value, vlen); 506 if (content_type != ctx->msg->data_type) { 507 pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n", 508 ctx->msg->data_type, sinfo->index, 509 content_type); 510 return -EBADMSG; 511 } 512 return 0; 513 514 case OID_signingTime: 515 if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set)) 516 goto repeated; 517 /* Should we check that the signing time is consistent 518 * with the signer's X.509 cert? 519 */ 520 return x509_decode_time(&sinfo->signing_time, 521 hdrlen, tag, value, vlen); 522 523 case OID_messageDigest: 524 if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set)) 525 goto repeated; 526 if (tag != ASN1_OTS) 527 return -EBADMSG; 528 sinfo->msgdigest = value; 529 sinfo->msgdigest_len = vlen; 530 return 0; 531 532 case OID_smimeCapabilites: 533 if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set)) 534 goto repeated; 535 if (ctx->msg->data_type != OID_msIndirectData) { 536 pr_warn("S/MIME Caps only allowed with Authenticode\n"); 537 return -EKEYREJECTED; 538 } 539 return 0; 540 541 /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE 542 * char URLs and cont[1] 8-bit char URLs. 543 * 544 * Microsoft StatementType seems to contain a list of OIDs that 545 * are also used as extendedKeyUsage types in X.509 certs. 546 */ 547 case OID_msSpOpusInfo: 548 if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) 549 goto repeated; 550 goto authenticode_check; 551 case OID_msStatementType: 552 if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set)) 553 goto repeated; 554 authenticode_check: 555 if (ctx->msg->data_type != OID_msIndirectData) { 556 pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n"); 557 return -EKEYREJECTED; 558 } 559 /* I'm not sure how to validate these */ 560 return 0; 561 default: 562 return 0; 563 } 564 565 repeated: 566 /* We permit max one item per AuthenticatedAttribute and no repeats */ 567 pr_warn("Repeated/multivalue AuthAttrs not permitted\n"); 568 return -EKEYREJECTED; 569 } 570 571 /* 572 * Note the set of auth attributes for digestion purposes [RFC2315 sec 9.3] 573 */ 574 int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, 575 unsigned char tag, 576 const void *value, size_t vlen) 577 { 578 struct pkcs7_parse_context *ctx = context; 579 struct pkcs7_signed_info *sinfo = ctx->sinfo; 580 581 if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) || 582 !test_bit(sinfo_has_message_digest, &sinfo->aa_set)) { 583 pr_warn("Missing required AuthAttr\n"); 584 return -EBADMSG; 585 } 586 587 if (ctx->msg->data_type != OID_msIndirectData && 588 test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) { 589 pr_warn("Unexpected Authenticode AuthAttr\n"); 590 return -EBADMSG; 591 } 592 593 /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */ 594 sinfo->authattrs = value - (hdrlen - 1); 595 sinfo->authattrs_len = vlen + (hdrlen - 1); 596 return 0; 597 } 598 599 /* 600 * Note the issuing certificate serial number 601 */ 602 int pkcs7_sig_note_serial(void *context, size_t hdrlen, 603 unsigned char tag, 604 const void *value, size_t vlen) 605 { 606 struct pkcs7_parse_context *ctx = context; 607 ctx->raw_serial = value; 608 ctx->raw_serial_size = vlen; 609 return 0; 610 } 611 612 /* 613 * Note the issuer's name 614 */ 615 int pkcs7_sig_note_issuer(void *context, size_t hdrlen, 616 unsigned char tag, 617 const void *value, size_t vlen) 618 { 619 struct pkcs7_parse_context *ctx = context; 620 ctx->raw_issuer = value; 621 ctx->raw_issuer_size = vlen; 622 return 0; 623 } 624 625 /* 626 * Note the issuing cert's subjectKeyIdentifier 627 */ 628 int pkcs7_sig_note_skid(void *context, size_t hdrlen, 629 unsigned char tag, 630 const void *value, size_t vlen) 631 { 632 struct pkcs7_parse_context *ctx = context; 633 634 pr_devel("SKID: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); 635 636 ctx->raw_skid = value; 637 ctx->raw_skid_size = vlen; 638 return 0; 639 } 640 641 /* 642 * Note the signature data 643 */ 644 int pkcs7_sig_note_signature(void *context, size_t hdrlen, 645 unsigned char tag, 646 const void *value, size_t vlen) 647 { 648 struct pkcs7_parse_context *ctx = context; 649 650 ctx->sinfo->sig->s = kmemdup(value, vlen, GFP_KERNEL); 651 if (!ctx->sinfo->sig->s) 652 return -ENOMEM; 653 654 ctx->sinfo->sig->s_size = vlen; 655 return 0; 656 } 657 658 /* 659 * Note a signature information block 660 */ 661 int pkcs7_note_signed_info(void *context, size_t hdrlen, 662 unsigned char tag, 663 const void *value, size_t vlen) 664 { 665 struct pkcs7_parse_context *ctx = context; 666 struct pkcs7_signed_info *sinfo = ctx->sinfo; 667 struct asymmetric_key_id *kid; 668 669 if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) { 670 pr_warn("Authenticode requires AuthAttrs\n"); 671 return -EBADMSG; 672 } 673 674 /* Generate cert issuer + serial number key ID */ 675 if (!ctx->expect_skid) { 676 kid = asymmetric_key_generate_id(ctx->raw_serial, 677 ctx->raw_serial_size, 678 ctx->raw_issuer, 679 ctx->raw_issuer_size); 680 } else { 681 kid = asymmetric_key_generate_id(ctx->raw_skid, 682 ctx->raw_skid_size, 683 "", 0); 684 } 685 if (IS_ERR(kid)) 686 return PTR_ERR(kid); 687 688 pr_devel("SINFO KID: %u [%*phN]\n", kid->len, kid->len, kid->data); 689 690 sinfo->sig->auth_ids[0] = kid; 691 sinfo->index = ++ctx->sinfo_index; 692 *ctx->ppsinfo = sinfo; 693 ctx->ppsinfo = &sinfo->next; 694 ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL); 695 if (!ctx->sinfo) 696 return -ENOMEM; 697 ctx->sinfo->sig = kzalloc(sizeof(struct public_key_signature), 698 GFP_KERNEL); 699 if (!ctx->sinfo->sig) 700 return -ENOMEM; 701 return 0; 702 } 703