1 /* Request a key from userspace 2 * 3 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * See Documentation/security/keys/request-key.rst 12 */ 13 14 #include <linux/export.h> 15 #include <linux/sched.h> 16 #include <linux/kmod.h> 17 #include <linux/err.h> 18 #include <linux/keyctl.h> 19 #include <linux/slab.h> 20 #include "internal.h" 21 #include <keys/request_key_auth-type.h> 22 23 #define key_negative_timeout 60 /* default timeout on a negative key's existence */ 24 25 static struct key *check_cached_key(struct keyring_search_context *ctx) 26 { 27 #ifdef CONFIG_KEYS_REQUEST_CACHE 28 struct key *key = current->cached_requested_key; 29 30 if (key && 31 ctx->match_data.cmp(key, &ctx->match_data) && 32 !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | 33 (1 << KEY_FLAG_REVOKED)))) 34 return key_get(key); 35 #endif 36 return NULL; 37 } 38 39 static void cache_requested_key(struct key *key) 40 { 41 #ifdef CONFIG_KEYS_REQUEST_CACHE 42 struct task_struct *t = current; 43 44 key_put(t->cached_requested_key); 45 t->cached_requested_key = key_get(key); 46 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); 47 #endif 48 } 49 50 /** 51 * complete_request_key - Complete the construction of a key. 52 * @authkey: The authorisation key. 53 * @error: The success or failute of the construction. 54 * 55 * Complete the attempt to construct a key. The key will be negated 56 * if an error is indicated. The authorisation key will be revoked 57 * unconditionally. 58 */ 59 void complete_request_key(struct key *authkey, int error) 60 { 61 struct request_key_auth *rka = get_request_key_auth(authkey); 62 struct key *key = rka->target_key; 63 64 kenter("%d{%d},%d", authkey->serial, key->serial, error); 65 66 if (error < 0) 67 key_negate_and_link(key, key_negative_timeout, NULL, authkey); 68 else 69 key_revoke(authkey); 70 } 71 EXPORT_SYMBOL(complete_request_key); 72 73 /* 74 * Initialise a usermode helper that is going to have a specific session 75 * keyring. 76 * 77 * This is called in context of freshly forked kthread before kernel_execve(), 78 * so we can simply install the desired session_keyring at this point. 79 */ 80 static int umh_keys_init(struct subprocess_info *info, struct cred *cred) 81 { 82 struct key *keyring = info->data; 83 84 return install_session_keyring_to_cred(cred, keyring); 85 } 86 87 /* 88 * Clean up a usermode helper with session keyring. 89 */ 90 static void umh_keys_cleanup(struct subprocess_info *info) 91 { 92 struct key *keyring = info->data; 93 key_put(keyring); 94 } 95 96 /* 97 * Call a usermode helper with a specific session keyring. 98 */ 99 static int call_usermodehelper_keys(const char *path, char **argv, char **envp, 100 struct key *session_keyring, int wait) 101 { 102 struct subprocess_info *info; 103 104 info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL, 105 umh_keys_init, umh_keys_cleanup, 106 session_keyring); 107 if (!info) 108 return -ENOMEM; 109 110 key_get(session_keyring); 111 return call_usermodehelper_exec(info, wait); 112 } 113 114 /* 115 * Request userspace finish the construction of a key 116 * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring>" 117 */ 118 static int call_sbin_request_key(struct key *authkey, void *aux) 119 { 120 static char const request_key[] = "/sbin/request-key"; 121 struct request_key_auth *rka = get_request_key_auth(authkey); 122 const struct cred *cred = current_cred(); 123 key_serial_t prkey, sskey; 124 struct key *key = rka->target_key, *keyring, *session; 125 char *argv[9], *envp[3], uid_str[12], gid_str[12]; 126 char key_str[12], keyring_str[3][12]; 127 char desc[20]; 128 int ret, i; 129 130 kenter("{%d},{%d},%s", key->serial, authkey->serial, rka->op); 131 132 ret = install_user_keyrings(); 133 if (ret < 0) 134 goto error_alloc; 135 136 /* allocate a new session keyring */ 137 sprintf(desc, "_req.%u", key->serial); 138 139 cred = get_current_cred(); 140 keyring = keyring_alloc(desc, cred->fsuid, cred->fsgid, cred, 141 KEY_POS_ALL | KEY_USR_VIEW | KEY_USR_READ, 142 KEY_ALLOC_QUOTA_OVERRUN, NULL, NULL); 143 put_cred(cred); 144 if (IS_ERR(keyring)) { 145 ret = PTR_ERR(keyring); 146 goto error_alloc; 147 } 148 149 /* attach the auth key to the session keyring */ 150 ret = key_link(keyring, authkey); 151 if (ret < 0) 152 goto error_link; 153 154 /* record the UID and GID */ 155 sprintf(uid_str, "%d", from_kuid(&init_user_ns, cred->fsuid)); 156 sprintf(gid_str, "%d", from_kgid(&init_user_ns, cred->fsgid)); 157 158 /* we say which key is under construction */ 159 sprintf(key_str, "%d", key->serial); 160 161 /* we specify the process's default keyrings */ 162 sprintf(keyring_str[0], "%d", 163 cred->thread_keyring ? cred->thread_keyring->serial : 0); 164 165 prkey = 0; 166 if (cred->process_keyring) 167 prkey = cred->process_keyring->serial; 168 sprintf(keyring_str[1], "%d", prkey); 169 170 session = cred->session_keyring; 171 if (!session) 172 session = cred->user->session_keyring; 173 sskey = session->serial; 174 175 sprintf(keyring_str[2], "%d", sskey); 176 177 /* set up a minimal environment */ 178 i = 0; 179 envp[i++] = "HOME=/"; 180 envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; 181 envp[i] = NULL; 182 183 /* set up the argument list */ 184 i = 0; 185 argv[i++] = (char *)request_key; 186 argv[i++] = (char *)rka->op; 187 argv[i++] = key_str; 188 argv[i++] = uid_str; 189 argv[i++] = gid_str; 190 argv[i++] = keyring_str[0]; 191 argv[i++] = keyring_str[1]; 192 argv[i++] = keyring_str[2]; 193 argv[i] = NULL; 194 195 /* do it */ 196 ret = call_usermodehelper_keys(request_key, argv, envp, keyring, 197 UMH_WAIT_PROC); 198 kdebug("usermode -> 0x%x", ret); 199 if (ret >= 0) { 200 /* ret is the exit/wait code */ 201 if (test_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags) || 202 key_validate(key) < 0) 203 ret = -ENOKEY; 204 else 205 /* ignore any errors from userspace if the key was 206 * instantiated */ 207 ret = 0; 208 } 209 210 error_link: 211 key_put(keyring); 212 213 error_alloc: 214 complete_request_key(authkey, ret); 215 kleave(" = %d", ret); 216 return ret; 217 } 218 219 /* 220 * Call out to userspace for key construction. 221 * 222 * Program failure is ignored in favour of key status. 223 */ 224 static int construct_key(struct key *key, const void *callout_info, 225 size_t callout_len, void *aux, 226 struct key *dest_keyring) 227 { 228 request_key_actor_t actor; 229 struct key *authkey; 230 int ret; 231 232 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux); 233 234 /* allocate an authorisation key */ 235 authkey = request_key_auth_new(key, "create", callout_info, callout_len, 236 dest_keyring); 237 if (IS_ERR(authkey)) 238 return PTR_ERR(authkey); 239 240 /* Make the call */ 241 actor = call_sbin_request_key; 242 if (key->type->request_key) 243 actor = key->type->request_key; 244 245 ret = actor(authkey, aux); 246 247 /* check that the actor called complete_request_key() prior to 248 * returning an error */ 249 WARN_ON(ret < 0 && 250 !test_bit(KEY_FLAG_INVALIDATED, &authkey->flags)); 251 252 key_put(authkey); 253 kleave(" = %d", ret); 254 return ret; 255 } 256 257 /* 258 * Get the appropriate destination keyring for the request. 259 * 260 * The keyring selected is returned with an extra reference upon it which the 261 * caller must release. 262 */ 263 static int construct_get_dest_keyring(struct key **_dest_keyring) 264 { 265 struct request_key_auth *rka; 266 const struct cred *cred = current_cred(); 267 struct key *dest_keyring = *_dest_keyring, *authkey; 268 int ret; 269 270 kenter("%p", dest_keyring); 271 272 /* find the appropriate keyring */ 273 if (dest_keyring) { 274 /* the caller supplied one */ 275 key_get(dest_keyring); 276 } else { 277 bool do_perm_check = true; 278 279 /* use a default keyring; falling through the cases until we 280 * find one that we actually have */ 281 switch (cred->jit_keyring) { 282 case KEY_REQKEY_DEFL_DEFAULT: 283 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: 284 if (cred->request_key_auth) { 285 authkey = cred->request_key_auth; 286 down_read(&authkey->sem); 287 rka = get_request_key_auth(authkey); 288 if (!test_bit(KEY_FLAG_REVOKED, 289 &authkey->flags)) 290 dest_keyring = 291 key_get(rka->dest_keyring); 292 up_read(&authkey->sem); 293 if (dest_keyring) { 294 do_perm_check = false; 295 break; 296 } 297 } 298 299 /* fall through */ 300 case KEY_REQKEY_DEFL_THREAD_KEYRING: 301 dest_keyring = key_get(cred->thread_keyring); 302 if (dest_keyring) 303 break; 304 305 /* fall through */ 306 case KEY_REQKEY_DEFL_PROCESS_KEYRING: 307 dest_keyring = key_get(cred->process_keyring); 308 if (dest_keyring) 309 break; 310 311 /* fall through */ 312 case KEY_REQKEY_DEFL_SESSION_KEYRING: 313 dest_keyring = key_get(cred->session_keyring); 314 315 if (dest_keyring) 316 break; 317 318 /* fall through */ 319 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: 320 dest_keyring = 321 key_get(READ_ONCE(cred->user->session_keyring)); 322 break; 323 324 case KEY_REQKEY_DEFL_USER_KEYRING: 325 dest_keyring = 326 key_get(READ_ONCE(cred->user->uid_keyring)); 327 break; 328 329 case KEY_REQKEY_DEFL_GROUP_KEYRING: 330 default: 331 BUG(); 332 } 333 334 /* 335 * Require Write permission on the keyring. This is essential 336 * because the default keyring may be the session keyring, and 337 * joining a keyring only requires Search permission. 338 * 339 * However, this check is skipped for the "requestor keyring" so 340 * that /sbin/request-key can itself use request_key() to add 341 * keys to the original requestor's destination keyring. 342 */ 343 if (dest_keyring && do_perm_check) { 344 ret = key_permission(make_key_ref(dest_keyring, 1), 345 KEY_NEED_WRITE); 346 if (ret) { 347 key_put(dest_keyring); 348 return ret; 349 } 350 } 351 } 352 353 *_dest_keyring = dest_keyring; 354 kleave(" [dk %d]", key_serial(dest_keyring)); 355 return 0; 356 } 357 358 /* 359 * Allocate a new key in under-construction state and attempt to link it in to 360 * the requested keyring. 361 * 362 * May return a key that's already under construction instead if there was a 363 * race between two thread calling request_key(). 364 */ 365 static int construct_alloc_key(struct keyring_search_context *ctx, 366 struct key *dest_keyring, 367 unsigned long flags, 368 struct key_user *user, 369 struct key **_key) 370 { 371 struct assoc_array_edit *edit = NULL; 372 struct key *key; 373 key_perm_t perm; 374 key_ref_t key_ref; 375 int ret; 376 377 kenter("%s,%s,,,", 378 ctx->index_key.type->name, ctx->index_key.description); 379 380 *_key = NULL; 381 mutex_lock(&user->cons_lock); 382 383 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; 384 perm |= KEY_USR_VIEW; 385 if (ctx->index_key.type->read) 386 perm |= KEY_POS_READ; 387 if (ctx->index_key.type == &key_type_keyring || 388 ctx->index_key.type->update) 389 perm |= KEY_POS_WRITE; 390 391 key = key_alloc(ctx->index_key.type, ctx->index_key.description, 392 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred, 393 perm, flags, NULL); 394 if (IS_ERR(key)) 395 goto alloc_failed; 396 397 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); 398 399 if (dest_keyring) { 400 ret = __key_link_lock(dest_keyring, &ctx->index_key); 401 if (ret < 0) 402 goto link_lock_failed; 403 ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit); 404 if (ret < 0) 405 goto link_prealloc_failed; 406 } 407 408 /* attach the key to the destination keyring under lock, but we do need 409 * to do another check just in case someone beat us to it whilst we 410 * waited for locks */ 411 mutex_lock(&key_construction_mutex); 412 413 rcu_read_lock(); 414 key_ref = search_process_keyrings_rcu(ctx); 415 rcu_read_unlock(); 416 if (!IS_ERR(key_ref)) 417 goto key_already_present; 418 419 if (dest_keyring) 420 __key_link(key, &edit); 421 422 mutex_unlock(&key_construction_mutex); 423 if (dest_keyring) 424 __key_link_end(dest_keyring, &ctx->index_key, edit); 425 mutex_unlock(&user->cons_lock); 426 *_key = key; 427 kleave(" = 0 [%d]", key_serial(key)); 428 return 0; 429 430 /* the key is now present - we tell the caller that we found it by 431 * returning -EINPROGRESS */ 432 key_already_present: 433 key_put(key); 434 mutex_unlock(&key_construction_mutex); 435 key = key_ref_to_ptr(key_ref); 436 if (dest_keyring) { 437 ret = __key_link_check_live_key(dest_keyring, key); 438 if (ret == 0) 439 __key_link(key, &edit); 440 __key_link_end(dest_keyring, &ctx->index_key, edit); 441 if (ret < 0) 442 goto link_check_failed; 443 } 444 mutex_unlock(&user->cons_lock); 445 *_key = key; 446 kleave(" = -EINPROGRESS [%d]", key_serial(key)); 447 return -EINPROGRESS; 448 449 link_check_failed: 450 mutex_unlock(&user->cons_lock); 451 key_put(key); 452 kleave(" = %d [linkcheck]", ret); 453 return ret; 454 455 link_prealloc_failed: 456 __key_link_end(dest_keyring, &ctx->index_key, edit); 457 link_lock_failed: 458 mutex_unlock(&user->cons_lock); 459 key_put(key); 460 kleave(" = %d [prelink]", ret); 461 return ret; 462 463 alloc_failed: 464 mutex_unlock(&user->cons_lock); 465 kleave(" = %ld", PTR_ERR(key)); 466 return PTR_ERR(key); 467 } 468 469 /* 470 * Commence key construction. 471 */ 472 static struct key *construct_key_and_link(struct keyring_search_context *ctx, 473 const char *callout_info, 474 size_t callout_len, 475 void *aux, 476 struct key *dest_keyring, 477 unsigned long flags) 478 { 479 struct key_user *user; 480 struct key *key; 481 int ret; 482 483 kenter(""); 484 485 if (ctx->index_key.type == &key_type_keyring) 486 return ERR_PTR(-EPERM); 487 488 ret = construct_get_dest_keyring(&dest_keyring); 489 if (ret) 490 goto error; 491 492 user = key_user_lookup(current_fsuid()); 493 if (!user) { 494 ret = -ENOMEM; 495 goto error_put_dest_keyring; 496 } 497 498 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); 499 key_user_put(user); 500 501 if (ret == 0) { 502 ret = construct_key(key, callout_info, callout_len, aux, 503 dest_keyring); 504 if (ret < 0) { 505 kdebug("cons failed"); 506 goto construction_failed; 507 } 508 } else if (ret == -EINPROGRESS) { 509 ret = 0; 510 } else { 511 goto error_put_dest_keyring; 512 } 513 514 key_put(dest_keyring); 515 kleave(" = key %d", key_serial(key)); 516 return key; 517 518 construction_failed: 519 key_negate_and_link(key, key_negative_timeout, NULL, NULL); 520 key_put(key); 521 error_put_dest_keyring: 522 key_put(dest_keyring); 523 error: 524 kleave(" = %d", ret); 525 return ERR_PTR(ret); 526 } 527 528 /** 529 * request_key_and_link - Request a key and cache it in a keyring. 530 * @type: The type of key we want. 531 * @description: The searchable description of the key. 532 * @callout_info: The data to pass to the instantiation upcall (or NULL). 533 * @callout_len: The length of callout_info. 534 * @aux: Auxiliary data for the upcall. 535 * @dest_keyring: Where to cache the key. 536 * @flags: Flags to key_alloc(). 537 * 538 * A key matching the specified criteria is searched for in the process's 539 * keyrings and returned with its usage count incremented if found. Otherwise, 540 * if callout_info is not NULL, a key will be allocated and some service 541 * (probably in userspace) will be asked to instantiate it. 542 * 543 * If successfully found or created, the key will be linked to the destination 544 * keyring if one is provided. 545 * 546 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED 547 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was 548 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT 549 * if insufficient key quota was available to create a new key; or -ENOMEM if 550 * insufficient memory was available. 551 * 552 * If the returned key was created, then it may still be under construction, 553 * and wait_for_key_construction() should be used to wait for that to complete. 554 */ 555 struct key *request_key_and_link(struct key_type *type, 556 const char *description, 557 const void *callout_info, 558 size_t callout_len, 559 void *aux, 560 struct key *dest_keyring, 561 unsigned long flags) 562 { 563 struct keyring_search_context ctx = { 564 .index_key.type = type, 565 .index_key.description = description, 566 .index_key.desc_len = strlen(description), 567 .cred = current_cred(), 568 .match_data.cmp = key_default_cmp, 569 .match_data.raw_data = description, 570 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, 571 .flags = (KEYRING_SEARCH_DO_STATE_CHECK | 572 KEYRING_SEARCH_SKIP_EXPIRED), 573 }; 574 struct key *key; 575 key_ref_t key_ref; 576 int ret; 577 578 kenter("%s,%s,%p,%zu,%p,%p,%lx", 579 ctx.index_key.type->name, ctx.index_key.description, 580 callout_info, callout_len, aux, dest_keyring, flags); 581 582 if (type->match_preparse) { 583 ret = type->match_preparse(&ctx.match_data); 584 if (ret < 0) { 585 key = ERR_PTR(ret); 586 goto error; 587 } 588 } 589 590 key = check_cached_key(&ctx); 591 if (key) 592 return key; 593 594 /* search all the process keyrings for a key */ 595 rcu_read_lock(); 596 key_ref = search_process_keyrings_rcu(&ctx); 597 rcu_read_unlock(); 598 599 if (!IS_ERR(key_ref)) { 600 if (dest_keyring) { 601 ret = key_task_permission(key_ref, current_cred(), 602 KEY_NEED_LINK); 603 if (ret < 0) { 604 key_ref_put(key_ref); 605 key = ERR_PTR(ret); 606 goto error_free; 607 } 608 } 609 610 key = key_ref_to_ptr(key_ref); 611 if (dest_keyring) { 612 ret = key_link(dest_keyring, key); 613 if (ret < 0) { 614 key_put(key); 615 key = ERR_PTR(ret); 616 goto error_free; 617 } 618 } 619 620 /* Only cache the key on immediate success */ 621 cache_requested_key(key); 622 } else if (PTR_ERR(key_ref) != -EAGAIN) { 623 key = ERR_CAST(key_ref); 624 } else { 625 /* the search failed, but the keyrings were searchable, so we 626 * should consult userspace if we can */ 627 key = ERR_PTR(-ENOKEY); 628 if (!callout_info) 629 goto error_free; 630 631 key = construct_key_and_link(&ctx, callout_info, callout_len, 632 aux, dest_keyring, flags); 633 } 634 635 error_free: 636 if (type->match_free) 637 type->match_free(&ctx.match_data); 638 error: 639 kleave(" = %p", key); 640 return key; 641 } 642 643 /** 644 * wait_for_key_construction - Wait for construction of a key to complete 645 * @key: The key being waited for. 646 * @intr: Whether to wait interruptibly. 647 * 648 * Wait for a key to finish being constructed. 649 * 650 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY 651 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was 652 * revoked or expired. 653 */ 654 int wait_for_key_construction(struct key *key, bool intr) 655 { 656 int ret; 657 658 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT, 659 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); 660 if (ret) 661 return -ERESTARTSYS; 662 ret = key_read_state(key); 663 if (ret < 0) 664 return ret; 665 return key_validate(key); 666 } 667 EXPORT_SYMBOL(wait_for_key_construction); 668 669 /** 670 * request_key - Request a key and wait for construction 671 * @type: Type of key. 672 * @description: The searchable description of the key. 673 * @callout_info: The data to pass to the instantiation upcall (or NULL). 674 * 675 * As for request_key_and_link() except that it does not add the returned key 676 * to a keyring if found, new keys are always allocated in the user's quota, 677 * the callout_info must be a NUL-terminated string and no auxiliary data can 678 * be passed. 679 * 680 * Furthermore, it then works as wait_for_key_construction() to wait for the 681 * completion of keys undergoing construction with a non-interruptible wait. 682 */ 683 struct key *request_key(struct key_type *type, 684 const char *description, 685 const char *callout_info) 686 { 687 struct key *key; 688 size_t callout_len = 0; 689 int ret; 690 691 if (callout_info) 692 callout_len = strlen(callout_info); 693 key = request_key_and_link(type, description, callout_info, callout_len, 694 NULL, NULL, KEY_ALLOC_IN_QUOTA); 695 if (!IS_ERR(key)) { 696 ret = wait_for_key_construction(key, false); 697 if (ret < 0) { 698 key_put(key); 699 return ERR_PTR(ret); 700 } 701 } 702 return key; 703 } 704 EXPORT_SYMBOL(request_key); 705 706 /** 707 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller 708 * @type: The type of key we want. 709 * @description: The searchable description of the key. 710 * @callout_info: The data to pass to the instantiation upcall (or NULL). 711 * @callout_len: The length of callout_info. 712 * @aux: Auxiliary data for the upcall. 713 * 714 * As for request_key_and_link() except that it does not add the returned key 715 * to a keyring if found and new keys are always allocated in the user's quota. 716 * 717 * Furthermore, it then works as wait_for_key_construction() to wait for the 718 * completion of keys undergoing construction with a non-interruptible wait. 719 */ 720 struct key *request_key_with_auxdata(struct key_type *type, 721 const char *description, 722 const void *callout_info, 723 size_t callout_len, 724 void *aux) 725 { 726 struct key *key; 727 int ret; 728 729 key = request_key_and_link(type, description, callout_info, callout_len, 730 aux, NULL, KEY_ALLOC_IN_QUOTA); 731 if (!IS_ERR(key)) { 732 ret = wait_for_key_construction(key, false); 733 if (ret < 0) { 734 key_put(key); 735 return ERR_PTR(ret); 736 } 737 } 738 return key; 739 } 740 EXPORT_SYMBOL(request_key_with_auxdata); 741 742 /* 743 * request_key_async - Request a key (allow async construction) 744 * @type: Type of key. 745 * @description: The searchable description of the key. 746 * @callout_info: The data to pass to the instantiation upcall (or NULL). 747 * @callout_len: The length of callout_info. 748 * 749 * As for request_key_and_link() except that it does not add the returned key 750 * to a keyring if found, new keys are always allocated in the user's quota and 751 * no auxiliary data can be passed. 752 * 753 * The caller should call wait_for_key_construction() to wait for the 754 * completion of the returned key if it is still undergoing construction. 755 */ 756 struct key *request_key_async(struct key_type *type, 757 const char *description, 758 const void *callout_info, 759 size_t callout_len) 760 { 761 return request_key_and_link(type, description, callout_info, 762 callout_len, NULL, NULL, 763 KEY_ALLOC_IN_QUOTA); 764 } 765 EXPORT_SYMBOL(request_key_async); 766 767 /* 768 * request a key with auxiliary data for the upcaller (allow async construction) 769 * @type: Type of key. 770 * @description: The searchable description of the key. 771 * @callout_info: The data to pass to the instantiation upcall (or NULL). 772 * @callout_len: The length of callout_info. 773 * @aux: Auxiliary data for the upcall. 774 * 775 * As for request_key_and_link() except that it does not add the returned key 776 * to a keyring if found and new keys are always allocated in the user's quota. 777 * 778 * The caller should call wait_for_key_construction() to wait for the 779 * completion of the returned key if it is still undergoing construction. 780 */ 781 struct key *request_key_async_with_auxdata(struct key_type *type, 782 const char *description, 783 const void *callout_info, 784 size_t callout_len, 785 void *aux) 786 { 787 return request_key_and_link(type, description, callout_info, 788 callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA); 789 } 790 EXPORT_SYMBOL(request_key_async_with_auxdata); 791 792 /** 793 * request_key_rcu - Request key from RCU-read-locked context 794 * @type: The type of key we want. 795 * @description: The name of the key we want. 796 * 797 * Request a key from a context that we may not sleep in (such as RCU-mode 798 * pathwalk). Keys under construction are ignored. 799 * 800 * Return a pointer to the found key if successful, -ENOKEY if we couldn't find 801 * a key or some other error if the key found was unsuitable or inaccessible. 802 */ 803 struct key *request_key_rcu(struct key_type *type, const char *description) 804 { 805 struct keyring_search_context ctx = { 806 .index_key.type = type, 807 .index_key.description = description, 808 .index_key.desc_len = strlen(description), 809 .cred = current_cred(), 810 .match_data.cmp = key_default_cmp, 811 .match_data.raw_data = description, 812 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, 813 .flags = (KEYRING_SEARCH_DO_STATE_CHECK | 814 KEYRING_SEARCH_SKIP_EXPIRED), 815 }; 816 struct key *key; 817 key_ref_t key_ref; 818 819 kenter("%s,%s", type->name, description); 820 821 key = check_cached_key(&ctx); 822 if (key) 823 return key; 824 825 /* search all the process keyrings for a key */ 826 key_ref = search_process_keyrings_rcu(&ctx); 827 if (IS_ERR(key_ref)) { 828 key = ERR_CAST(key_ref); 829 if (PTR_ERR(key_ref) == -EAGAIN) 830 key = ERR_PTR(-ENOKEY); 831 } else { 832 key = key_ref_to_ptr(key_ref); 833 cache_requested_key(key); 834 } 835 836 kleave(" = %p", key); 837 return key; 838 } 839 EXPORT_SYMBOL(request_key_rcu); 840