Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 | // SPDX-License-Identifier: GPL-2.0-or-later /* Asymmetric public-key cryptography key type * * See Documentation/crypto/asymmetric-keys.rst * * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) */ #include <keys/asymmetric-subtype.h> #include <keys/asymmetric-parser.h> #include <crypto/public_key.h> #include <linux/seq_file.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/ctype.h> #include <keys/system_keyring.h> #include <keys/user-type.h> #include "asymmetric_keys.h" const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = { [VERIFYING_MODULE_SIGNATURE] = "mod sig", [VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig", [VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig", [VERIFYING_KEY_SIGNATURE] = "key sig", [VERIFYING_KEY_SELF_SIGNATURE] = "key self sig", [VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig", }; EXPORT_SYMBOL_GPL(key_being_used_for); static LIST_HEAD(asymmetric_key_parsers); static DECLARE_RWSEM(asymmetric_key_parsers_sem); /** * find_asymmetric_key - Find a key by ID. * @keyring: The keys to search. * @id_0: The first ID to look for or NULL. * @id_1: The second ID to look for or NULL, matched together with @id_0 * against @keyring keys' id[0] and id[1]. * @id_2: The fallback ID to match against @keyring keys' id[2] if both of the * other IDs are NULL. * @partial: Use partial match for @id_0 and @id_1 if true, exact if false. * * Find a key in the given keyring by identifier. The preferred identifier is * the id_0 and the fallback identifier is the id_1. If both are given, the * former is matched (exactly or partially) against either of the sought key's * identifiers and the latter must match the found key's second identifier * exactly. If both are missing, id_2 must match the sought key's third * identifier exactly. */ struct key *find_asymmetric_key(struct key *keyring, const struct asymmetric_key_id *id_0, const struct asymmetric_key_id *id_1, const struct asymmetric_key_id *id_2, bool partial) { struct key *key; key_ref_t ref; const char *lookup; char *req, *p; int len; WARN_ON(!id_0 && !id_1 && !id_2); if (id_0) { lookup = id_0->data; len = id_0->len; } else if (id_1) { lookup = id_1->data; len = id_1->len; } else { lookup = id_2->data; len = id_2->len; } /* Construct an identifier "id:<keyid>". */ p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL); if (!req) return ERR_PTR(-ENOMEM); if (!id_0 && !id_1) { *p++ = 'd'; *p++ = 'n'; } else if (partial) { *p++ = 'i'; *p++ = 'd'; } else { *p++ = 'e'; *p++ = 'x'; } *p++ = ':'; p = bin2hex(p, lookup, len); *p = 0; pr_debug("Look up: \"%s\"\n", req); ref = keyring_search(make_key_ref(keyring, 1), &key_type_asymmetric, req, true); if (IS_ERR(ref)) pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref)); kfree(req); if (IS_ERR(ref)) { switch (PTR_ERR(ref)) { /* Hide some search errors */ case -EACCES: case -ENOTDIR: case -EAGAIN: return ERR_PTR(-ENOKEY); default: return ERR_CAST(ref); } } key = key_ref_to_ptr(ref); if (id_0 && id_1) { const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); if (!kids->id[1]) { pr_debug("First ID matches, but second is missing\n"); goto reject; } if (!asymmetric_key_id_same(id_1, kids->id[1])) { pr_debug("First ID matches, but second does not\n"); goto reject; } } pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key)); return key; reject: key_put(key); return ERR_PTR(-EKEYREJECTED); } EXPORT_SYMBOL_GPL(find_asymmetric_key); /** * asymmetric_key_generate_id: Construct an asymmetric key ID * @val_1: First binary blob * @len_1: Length of first binary blob * @val_2: Second binary blob * @len_2: Length of second binary blob * * Construct an asymmetric key ID from a pair of binary blobs. */ struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1, size_t len_1, const void *val_2, size_t len_2) { struct asymmetric_key_id *kid; kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2, GFP_KERNEL); if (!kid) return ERR_PTR(-ENOMEM); kid->len = len_1 + len_2; memcpy(kid->data, val_1, len_1); memcpy(kid->data + len_1, val_2, len_2); return kid; } EXPORT_SYMBOL_GPL(asymmetric_key_generate_id); /** * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same. * @kid1: The key ID to compare * @kid2: The key ID to compare */ bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1, const struct asymmetric_key_id *kid2) { if (!kid1 || !kid2) return false; if (kid1->len != kid2->len) return false; return memcmp(kid1->data, kid2->data, kid1->len) == 0; } EXPORT_SYMBOL_GPL(asymmetric_key_id_same); /** * asymmetric_key_id_partial - Return true if two asymmetric keys IDs * partially match * @kid1: The key ID to compare * @kid2: The key ID to compare */ bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1, const struct asymmetric_key_id *kid2) { if (!kid1 || !kid2) return false; if (kid1->len < kid2->len) return false; return memcmp(kid1->data + (kid1->len - kid2->len), kid2->data, kid2->len) == 0; } EXPORT_SYMBOL_GPL(asymmetric_key_id_partial); /** * asymmetric_match_key_ids - Search asymmetric key IDs 1 & 2 * @kids: The pair of key IDs to check * @match_id: The key ID we're looking for * @match: The match function to use */ static bool asymmetric_match_key_ids( const struct asymmetric_key_ids *kids, const struct asymmetric_key_id *match_id, bool (*match)(const struct asymmetric_key_id *kid1, const struct asymmetric_key_id *kid2)) { int i; if (!kids || !match_id) return false; for (i = 0; i < 2; i++) if (match(kids->id[i], match_id)) return true; return false; } /* helper function can be called directly with pre-allocated memory */ inline int __asymmetric_key_hex_to_key_id(const char *id, struct asymmetric_key_id *match_id, size_t hexlen) { match_id->len = hexlen; return hex2bin(match_id->data, id, hexlen); } /** * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID. * @id: The ID as a hex string. */ struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id) { struct asymmetric_key_id *match_id; size_t asciihexlen; int ret; if (!*id) return ERR_PTR(-EINVAL); asciihexlen = strlen(id); if (asciihexlen & 1) return ERR_PTR(-EINVAL); match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2, GFP_KERNEL); if (!match_id) return ERR_PTR(-ENOMEM); ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2); if (ret < 0) { kfree(match_id); return ERR_PTR(-EINVAL); } return match_id; } /* * Match asymmetric keys by an exact match on one of the first two IDs. */ static bool asymmetric_key_cmp(const struct key *key, const struct key_match_data *match_data) { const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); const struct asymmetric_key_id *match_id = match_data->preparsed; return asymmetric_match_key_ids(kids, match_id, asymmetric_key_id_same); } /* * Match asymmetric keys by a partial match on one of the first two IDs. */ static bool asymmetric_key_cmp_partial(const struct key *key, const struct key_match_data *match_data) { const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); const struct asymmetric_key_id *match_id = match_data->preparsed; return asymmetric_match_key_ids(kids, match_id, asymmetric_key_id_partial); } /* * Match asymmetric keys by an exact match on the third IDs. */ static bool asymmetric_key_cmp_name(const struct key *key, const struct key_match_data *match_data) { const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); const struct asymmetric_key_id *match_id = match_data->preparsed; return kids && asymmetric_key_id_same(kids->id[2], match_id); } /* * Preparse the match criterion. If we don't set lookup_type and cmp, * the default will be an exact match on the key description. * * There are some specifiers for matching key IDs rather than by the key * description: * * "id:<id>" - find a key by partial match on one of the first two IDs * "ex:<id>" - find a key by exact match on one of the first two IDs * "dn:<id>" - find a key by exact match on the third ID * * These have to be searched by iteration rather than by direct lookup because * the key is hashed according to its description. */ static int asymmetric_key_match_preparse(struct key_match_data *match_data) { struct asymmetric_key_id *match_id; const char *spec = match_data->raw_data; const char *id; bool (*cmp)(const struct key *, const struct key_match_data *) = asymmetric_key_cmp; if (!spec || !*spec) return -EINVAL; if (spec[0] == 'i' && spec[1] == 'd' && spec[2] == ':') { id = spec + 3; cmp = asymmetric_key_cmp_partial; } else if (spec[0] == 'e' && spec[1] == 'x' && spec[2] == ':') { id = spec + 3; } else if (spec[0] == 'd' && spec[1] == 'n' && spec[2] == ':') { id = spec + 3; cmp = asymmetric_key_cmp_name; } else { goto default_match; } match_id = asymmetric_key_hex_to_key_id(id); if (IS_ERR(match_id)) return PTR_ERR(match_id); match_data->preparsed = match_id; match_data->cmp = cmp; match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE; return 0; default_match: return 0; } /* * Free the preparsed the match criterion. */ static void asymmetric_key_match_free(struct key_match_data *match_data) { kfree(match_data->preparsed); } /* * Describe the asymmetric key */ static void asymmetric_key_describe(const struct key *key, struct seq_file *m) { const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key); const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); const struct asymmetric_key_id *kid; const unsigned char *p; int n; seq_puts(m, key->description); if (subtype) { seq_puts(m, ": "); subtype->describe(key, m); if (kids && kids->id[1]) { kid = kids->id[1]; seq_putc(m, ' '); n = kid->len; p = kid->data; if (n > 4) { p += n - 4; n = 4; } seq_printf(m, "%*phN", n, p); } seq_puts(m, " ["); /* put something here to indicate the key's capabilities */ seq_putc(m, ']'); } } /* * Preparse a asymmetric payload to get format the contents appropriately for the * internal payload to cut down on the number of scans of the data performed. * * We also generate a proposed description from the contents of the key that * can be used to name the key if the user doesn't want to provide one. */ static int asymmetric_key_preparse(struct key_preparsed_payload *prep) { struct asymmetric_key_parser *parser; int ret; pr_devel("==>%s()\n", __func__); if (prep->datalen == 0) return -EINVAL; down_read(&asymmetric_key_parsers_sem); ret = -EBADMSG; list_for_each_entry(parser, &asymmetric_key_parsers, link) { pr_debug("Trying parser '%s'\n", parser->name); ret = parser->parse(prep); if (ret != -EBADMSG) { pr_debug("Parser recognised the format (ret %d)\n", ret); break; } } up_read(&asymmetric_key_parsers_sem); pr_devel("<==%s() = %d\n", __func__, ret); return ret; } /* * Clean up the key ID list */ static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids) { int i; if (kids) { for (i = 0; i < ARRAY_SIZE(kids->id); i++) kfree(kids->id[i]); kfree(kids); } } /* * Clean up the preparse data */ static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep) { struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype]; struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids]; pr_devel("==>%s()\n", __func__); if (subtype) { subtype->destroy(prep->payload.data[asym_crypto], prep->payload.data[asym_auth]); module_put(subtype->owner); } asymmetric_key_free_kids(kids); kfree(prep->description); } /* * dispose of the data dangling from the corpse of a asymmetric key */ static void asymmetric_key_destroy(struct key *key) { struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key); struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids]; void *data = key->payload.data[asym_crypto]; void *auth = key->payload.data[asym_auth]; key->payload.data[asym_crypto] = NULL; key->payload.data[asym_subtype] = NULL; key->payload.data[asym_key_ids] = NULL; key->payload.data[asym_auth] = NULL; if (subtype) { subtype->destroy(data, auth); module_put(subtype->owner); } asymmetric_key_free_kids(kids); } static struct key_restriction *asymmetric_restriction_alloc( key_restrict_link_func_t check, struct key *key) { struct key_restriction *keyres = kzalloc(sizeof(struct key_restriction), GFP_KERNEL); if (!keyres) return ERR_PTR(-ENOMEM); keyres->check = check; keyres->key = key; keyres->keytype = &key_type_asymmetric; return keyres; } /* * look up keyring restrict functions for asymmetric keys */ static struct key_restriction *asymmetric_lookup_restriction( const char *restriction) { char *restrict_method; char *parse_buf; char *next; struct key_restriction *ret = ERR_PTR(-EINVAL); if (strcmp("builtin_trusted", restriction) == 0) return asymmetric_restriction_alloc( restrict_link_by_builtin_trusted, NULL); if (strcmp("builtin_and_secondary_trusted", restriction) == 0) return asymmetric_restriction_alloc( restrict_link_by_builtin_and_secondary_trusted, NULL); parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL); if (!parse_buf) return ERR_PTR(-ENOMEM); next = parse_buf; restrict_method = strsep(&next, ":"); if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) { char *key_text; key_serial_t serial; struct key *key; key_restrict_link_func_t link_fn = restrict_link_by_key_or_keyring; bool allow_null_key = false; key_text = strsep(&next, ":"); if (next) { if (strcmp(next, "chain") != 0) goto out; link_fn = restrict_link_by_key_or_keyring_chain; allow_null_key = true; } if (kstrtos32(key_text, 0, &serial) < 0) goto out; if ((serial == 0) && allow_null_key) { key = NULL; } else { key = key_lookup(serial); if (IS_ERR(key)) { ret = ERR_CAST(key); goto out; } } ret = asymmetric_restriction_alloc(link_fn, key); if (IS_ERR(ret)) key_put(key); } out: kfree(parse_buf); return ret; } int asymmetric_key_eds_op(struct kernel_pkey_params *params, const void *in, void *out) { const struct asymmetric_key_subtype *subtype; struct key *key = params->key; int ret; pr_devel("==>%s()\n", __func__); if (key->type != &key_type_asymmetric) return -EINVAL; subtype = asymmetric_key_subtype(key); if (!subtype || !key->payload.data[0]) return -EINVAL; if (!subtype->eds_op) return -ENOTSUPP; ret = subtype->eds_op(params, in, out); pr_devel("<==%s() = %d\n", __func__, ret); return ret; } static int asymmetric_key_verify_signature(struct kernel_pkey_params *params, const void *in, const void *in2) { struct public_key_signature sig = { .s_size = params->in2_len, .digest_size = params->in_len, .encoding = params->encoding, .hash_algo = params->hash_algo, .digest = (void *)in, .s = (void *)in2, }; return verify_signature(params->key, &sig); } struct key_type key_type_asymmetric = { .name = "asymmetric", .preparse = asymmetric_key_preparse, .free_preparse = asymmetric_key_free_preparse, .instantiate = generic_key_instantiate, .match_preparse = asymmetric_key_match_preparse, .match_free = asymmetric_key_match_free, .destroy = asymmetric_key_destroy, .describe = asymmetric_key_describe, .lookup_restriction = asymmetric_lookup_restriction, .asym_query = query_asymmetric_key, .asym_eds_op = asymmetric_key_eds_op, .asym_verify_signature = asymmetric_key_verify_signature, }; EXPORT_SYMBOL_GPL(key_type_asymmetric); /** * register_asymmetric_key_parser - Register a asymmetric key blob parser * @parser: The parser to register */ int register_asymmetric_key_parser(struct asymmetric_key_parser *parser) { struct asymmetric_key_parser *cursor; int ret; down_write(&asymmetric_key_parsers_sem); list_for_each_entry(cursor, &asymmetric_key_parsers, link) { if (strcmp(cursor->name, parser->name) == 0) { pr_err("Asymmetric key parser '%s' already registered\n", parser->name); ret = -EEXIST; goto out; } } list_add_tail(&parser->link, &asymmetric_key_parsers); pr_notice("Asymmetric key parser '%s' registered\n", parser->name); ret = 0; out: up_write(&asymmetric_key_parsers_sem); return ret; } EXPORT_SYMBOL_GPL(register_asymmetric_key_parser); /** * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser * @parser: The parser to unregister */ void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser) { down_write(&asymmetric_key_parsers_sem); list_del(&parser->link); up_write(&asymmetric_key_parsers_sem); pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name); } EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser); /* * Module stuff */ static int __init asymmetric_key_init(void) { return register_key_type(&key_type_asymmetric); } static void __exit asymmetric_key_cleanup(void) { unregister_key_type(&key_type_asymmetric); } module_init(asymmetric_key_init); module_exit(asymmetric_key_cleanup); |