1// SPDX-License-Identifier: GPL-2.0-or-later 2/* Request a key from userspace 3 * 4 * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 * 7 * See Documentation/security/keys/request-key.rst 8 */ 9 10#include <linux/export.h> 11#include <linux/sched.h> 12#include <linux/kmod.h> 13#include <linux/err.h> 14#include <linux/keyctl.h> 15#include <linux/slab.h> 16#include <net/net_namespace.h> 17#include "internal.h" 18#include <keys/request_key_auth-type.h> 19 20#define key_negative_timeout 60 /* default timeout on a negative key's existence */ 21 22static struct key *check_cached_key(struct keyring_search_context *ctx) 23{ 24#ifdef CONFIG_KEYS_REQUEST_CACHE 25 struct key *key = current->cached_requested_key; 26 27 if (key && 28 ctx->match_data.cmp(key, &ctx->match_data) && 29 !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | 30 (1 << KEY_FLAG_REVOKED)))) 31 return key_get(key); 32#endif 33 return NULL; 34} 35 36static void cache_requested_key(struct key *key) 37{ 38#ifdef CONFIG_KEYS_REQUEST_CACHE 39 struct task_struct *t = current; 40 41 /* Do not cache key if it is a kernel thread */ 42 if (!(t->flags & PF_KTHREAD)) { 43 key_put(t->cached_requested_key); 44 t->cached_requested_key = key_get(key); 45 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); 46 } 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 */ 59void 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} 71EXPORT_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 */ 80static 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 */ 90static 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 */ 99static 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 */ 118static 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, *user_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 = look_up_user_keyrings(NULL, &user_session); 133 if (ret < 0) 134 goto error_us; 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 = user_session; 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 210error_link: 211 key_put(keyring); 212 213error_alloc: 214 key_put(user_session); 215error_us: 216 complete_request_key(authkey, ret); 217 kleave(" = %d", ret); 218 return ret; 219} 220 221/* 222 * Call out to userspace for key construction. 223 * 224 * Program failure is ignored in favour of key status. 225 */ 226static int construct_key(struct key *key, const void *callout_info, 227 size_t callout_len, void *aux, 228 struct key *dest_keyring) 229{ 230 request_key_actor_t actor; 231 struct key *authkey; 232 int ret; 233 234 kenter("%d,%p,%zu,%p", key->serial, callout_info, callout_len, aux); 235 236 /* allocate an authorisation key */ 237 authkey = request_key_auth_new(key, "create", callout_info, callout_len, 238 dest_keyring); 239 if (IS_ERR(authkey)) 240 return PTR_ERR(authkey); 241 242 /* Make the call */ 243 actor = call_sbin_request_key; 244 if (key->type->request_key) 245 actor = key->type->request_key; 246 247 ret = actor(authkey, aux); 248 249 /* check that the actor called complete_request_key() prior to 250 * returning an error */ 251 WARN_ON(ret < 0 && 252 !test_bit(KEY_FLAG_INVALIDATED, &authkey->flags)); 253 254 key_put(authkey); 255 kleave(" = %d", ret); 256 return ret; 257} 258 259/* 260 * Get the appropriate destination keyring for the request. 261 * 262 * The keyring selected is returned with an extra reference upon it which the 263 * caller must release. 264 */ 265static int construct_get_dest_keyring(struct key **_dest_keyring) 266{ 267 struct request_key_auth *rka; 268 const struct cred *cred = current_cred(); 269 struct key *dest_keyring = *_dest_keyring, *authkey; 270 int ret; 271 272 kenter("%p", dest_keyring); 273 274 /* find the appropriate keyring */ 275 if (dest_keyring) { 276 /* the caller supplied one */ 277 key_get(dest_keyring); 278 } else { 279 bool do_perm_check = true; 280 281 /* use a default keyring; falling through the cases until we 282 * find one that we actually have */ 283 switch (cred->jit_keyring) { 284 case KEY_REQKEY_DEFL_DEFAULT: 285 case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: 286 if (cred->request_key_auth) { 287 authkey = cred->request_key_auth; 288 down_read(&authkey->sem); 289 rka = get_request_key_auth(authkey); 290 if (!test_bit(KEY_FLAG_REVOKED, 291 &authkey->flags)) 292 dest_keyring = 293 key_get(rka->dest_keyring); 294 up_read(&authkey->sem); 295 if (dest_keyring) { 296 do_perm_check = false; 297 break; 298 } 299 } 300 301 fallthrough; 302 case KEY_REQKEY_DEFL_THREAD_KEYRING: 303 dest_keyring = key_get(cred->thread_keyring); 304 if (dest_keyring) 305 break; 306 307 fallthrough; 308 case KEY_REQKEY_DEFL_PROCESS_KEYRING: 309 dest_keyring = key_get(cred->process_keyring); 310 if (dest_keyring) 311 break; 312 313 fallthrough; 314 case KEY_REQKEY_DEFL_SESSION_KEYRING: 315 dest_keyring = key_get(cred->session_keyring); 316 317 if (dest_keyring) 318 break; 319 320 fallthrough; 321 case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: 322 ret = look_up_user_keyrings(NULL, &dest_keyring); 323 if (ret < 0) 324 return ret; 325 break; 326 327 case KEY_REQKEY_DEFL_USER_KEYRING: 328 ret = look_up_user_keyrings(&dest_keyring, NULL); 329 if (ret < 0) 330 return ret; 331 break; 332 333 case KEY_REQKEY_DEFL_GROUP_KEYRING: 334 default: 335 BUG(); 336 } 337 338 /* 339 * Require Write permission on the keyring. This is essential 340 * because the default keyring may be the session keyring, and 341 * joining a keyring only requires Search permission. 342 * 343 * However, this check is skipped for the "requestor keyring" so 344 * that /sbin/request-key can itself use request_key() to add 345 * keys to the original requestor's destination keyring. 346 */ 347 if (dest_keyring && do_perm_check) { 348 ret = key_permission(make_key_ref(dest_keyring, 1), 349 KEY_NEED_WRITE); 350 if (ret) { 351 key_put(dest_keyring); 352 return ret; 353 } 354 } 355 } 356 357 *_dest_keyring = dest_keyring; 358 kleave(" [dk %d]", key_serial(dest_keyring)); 359 return 0; 360} 361 362/* 363 * Allocate a new key in under-construction state and attempt to link it in to 364 * the requested keyring. 365 * 366 * May return a key that's already under construction instead if there was a 367 * race between two thread calling request_key(). 368 */ 369static int construct_alloc_key(struct keyring_search_context *ctx, 370 struct key *dest_keyring, 371 unsigned long flags, 372 struct key_user *user, 373 struct key **_key) 374{ 375 struct assoc_array_edit *edit = NULL; 376 struct key *key; 377 key_perm_t perm; 378 key_ref_t key_ref; 379 int ret; 380 381 kenter("%s,%s,,,", 382 ctx->index_key.type->name, ctx->index_key.description); 383 384 *_key = NULL; 385 mutex_lock(&user->cons_lock); 386 387 perm = KEY_POS_VIEW | KEY_POS_SEARCH | KEY_POS_LINK | KEY_POS_SETATTR; 388 perm |= KEY_USR_VIEW; 389 if (ctx->index_key.type->read) 390 perm |= KEY_POS_READ; 391 if (ctx->index_key.type == &key_type_keyring || 392 ctx->index_key.type->update) 393 perm |= KEY_POS_WRITE; 394 395 key = key_alloc(ctx->index_key.type, ctx->index_key.description, 396 ctx->cred->fsuid, ctx->cred->fsgid, ctx->cred, 397 perm, flags, NULL); 398 if (IS_ERR(key)) 399 goto alloc_failed; 400 401 set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); 402 403 if (dest_keyring) { 404 ret = __key_link_lock(dest_keyring, &key->index_key); 405 if (ret < 0) 406 goto link_lock_failed; 407 } 408 409 /* 410 * Attach the key to the destination keyring under lock, but we do need 411 * to do another check just in case someone beat us to it whilst we 412 * waited for locks. 413 * 414 * The caller might specify a comparison function which looks for keys 415 * that do not exactly match but are still equivalent from the caller's 416 * perspective. The __key_link_begin() operation must be done only after 417 * an actual key is determined. 418 */ 419 mutex_lock(&key_construction_mutex); 420 421 rcu_read_lock(); 422 key_ref = search_process_keyrings_rcu(ctx); 423 rcu_read_unlock(); 424 if (!IS_ERR(key_ref)) 425 goto key_already_present; 426 427 if (dest_keyring) { 428 ret = __key_link_begin(dest_keyring, &key->index_key, &edit); 429 if (ret < 0) 430 goto link_alloc_failed; 431 __key_link(dest_keyring, key, &edit); 432 } 433 434 mutex_unlock(&key_construction_mutex); 435 if (dest_keyring) 436 __key_link_end(dest_keyring, &key->index_key, edit); 437 mutex_unlock(&user->cons_lock); 438 *_key = key; 439 kleave(" = 0 [%d]", key_serial(key)); 440 return 0; 441 442 /* the key is now present - we tell the caller that we found it by 443 * returning -EINPROGRESS */ 444key_already_present: 445 key_put(key); 446 mutex_unlock(&key_construction_mutex); 447 key = key_ref_to_ptr(key_ref); 448 if (dest_keyring) { 449 ret = __key_link_begin(dest_keyring, &key->index_key, &edit); 450 if (ret < 0) 451 goto link_alloc_failed_unlocked; 452 ret = __key_link_check_live_key(dest_keyring, key); 453 if (ret == 0) 454 __key_link(dest_keyring, key, &edit); 455 __key_link_end(dest_keyring, &key->index_key, edit); 456 if (ret < 0) 457 goto link_check_failed; 458 } 459 mutex_unlock(&user->cons_lock); 460 *_key = key; 461 kleave(" = -EINPROGRESS [%d]", key_serial(key)); 462 return -EINPROGRESS; 463 464link_check_failed: 465 mutex_unlock(&user->cons_lock); 466 key_put(key); 467 kleave(" = %d [linkcheck]", ret); 468 return ret; 469 470link_alloc_failed: 471 mutex_unlock(&key_construction_mutex); 472link_alloc_failed_unlocked: 473 __key_link_end(dest_keyring, &key->index_key, edit); 474link_lock_failed: 475 mutex_unlock(&user->cons_lock); 476 key_put(key); 477 kleave(" = %d [prelink]", ret); 478 return ret; 479 480alloc_failed: 481 mutex_unlock(&user->cons_lock); 482 kleave(" = %ld", PTR_ERR(key)); 483 return PTR_ERR(key); 484} 485 486/* 487 * Commence key construction. 488 */ 489static struct key *construct_key_and_link(struct keyring_search_context *ctx, 490 const char *callout_info, 491 size_t callout_len, 492 void *aux, 493 struct key *dest_keyring, 494 unsigned long flags) 495{ 496 struct key_user *user; 497 struct key *key; 498 int ret; 499 500 kenter(""); 501 502 if (ctx->index_key.type == &key_type_keyring) 503 return ERR_PTR(-EPERM); 504 505 ret = construct_get_dest_keyring(&dest_keyring); 506 if (ret) 507 goto error; 508 509 user = key_user_lookup(current_fsuid()); 510 if (!user) { 511 ret = -ENOMEM; 512 goto error_put_dest_keyring; 513 } 514 515 ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); 516 key_user_put(user); 517 518 if (ret == 0) { 519 ret = construct_key(key, callout_info, callout_len, aux, 520 dest_keyring); 521 if (ret < 0) { 522 kdebug("cons failed"); 523 goto construction_failed; 524 } 525 } else if (ret == -EINPROGRESS) { 526 ret = 0; 527 } else { 528 goto error_put_dest_keyring; 529 } 530 531 key_put(dest_keyring); 532 kleave(" = key %d", key_serial(key)); 533 return key; 534 535construction_failed: 536 key_negate_and_link(key, key_negative_timeout, NULL, NULL); 537 key_put(key); 538error_put_dest_keyring: 539 key_put(dest_keyring); 540error: 541 kleave(" = %d", ret); 542 return ERR_PTR(ret); 543} 544 545/** 546 * request_key_and_link - Request a key and cache it in a keyring. 547 * @type: The type of key we want. 548 * @description: The searchable description of the key. 549 * @domain_tag: The domain in which the key operates. 550 * @callout_info: The data to pass to the instantiation upcall (or NULL). 551 * @callout_len: The length of callout_info. 552 * @aux: Auxiliary data for the upcall. 553 * @dest_keyring: Where to cache the key. 554 * @flags: Flags to key_alloc(). 555 * 556 * A key matching the specified criteria (type, description, domain_tag) is 557 * searched for in the process's keyrings and returned with its usage count 558 * incremented if found. Otherwise, if callout_info is not NULL, a key will be 559 * allocated and some service (probably in userspace) will be asked to 560 * instantiate it. 561 * 562 * If successfully found or created, the key will be linked to the destination 563 * keyring if one is provided. 564 * 565 * Returns a pointer to the key if successful; -EACCES, -ENOKEY, -EKEYREVOKED 566 * or -EKEYEXPIRED if an inaccessible, negative, revoked or expired key was 567 * found; -ENOKEY if no key was found and no @callout_info was given; -EDQUOT 568 * if insufficient key quota was available to create a new key; or -ENOMEM if 569 * insufficient memory was available. 570 * 571 * If the returned key was created, then it may still be under construction, 572 * and wait_for_key_construction() should be used to wait for that to complete. 573 */ 574struct key *request_key_and_link(struct key_type *type, 575 const char *description, 576 struct key_tag *domain_tag, 577 const void *callout_info, 578 size_t callout_len, 579 void *aux, 580 struct key *dest_keyring, 581 unsigned long flags) 582{ 583 struct keyring_search_context ctx = { 584 .index_key.type = type, 585 .index_key.domain_tag = domain_tag, 586 .index_key.description = description, 587 .index_key.desc_len = strlen(description), 588 .cred = current_cred(), 589 .match_data.cmp = key_default_cmp, 590 .match_data.raw_data = description, 591 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, 592 .flags = (KEYRING_SEARCH_DO_STATE_CHECK | 593 KEYRING_SEARCH_SKIP_EXPIRED | 594 KEYRING_SEARCH_RECURSE), 595 }; 596 struct key *key; 597 key_ref_t key_ref; 598 int ret; 599 600 kenter("%s,%s,%p,%zu,%p,%p,%lx", 601 ctx.index_key.type->name, ctx.index_key.description, 602 callout_info, callout_len, aux, dest_keyring, flags); 603 604 if (type->match_preparse) { 605 ret = type->match_preparse(&ctx.match_data); 606 if (ret < 0) { 607 key = ERR_PTR(ret); 608 goto error; 609 } 610 } 611 612 key = check_cached_key(&ctx); 613 if (key) 614 goto error_free; 615 616 /* search all the process keyrings for a key */ 617 rcu_read_lock(); 618 key_ref = search_process_keyrings_rcu(&ctx); 619 rcu_read_unlock(); 620 621 if (!IS_ERR(key_ref)) { 622 if (dest_keyring) { 623 ret = key_task_permission(key_ref, current_cred(), 624 KEY_NEED_LINK); 625 if (ret < 0) { 626 key_ref_put(key_ref); 627 key = ERR_PTR(ret); 628 goto error_free; 629 } 630 } 631 632 key = key_ref_to_ptr(key_ref); 633 if (dest_keyring) { 634 ret = key_link(dest_keyring, key); 635 if (ret < 0) { 636 key_put(key); 637 key = ERR_PTR(ret); 638 goto error_free; 639 } 640 } 641 642 /* Only cache the key on immediate success */ 643 cache_requested_key(key); 644 } else if (PTR_ERR(key_ref) != -EAGAIN) { 645 key = ERR_CAST(key_ref); 646 } else { 647 /* the search failed, but the keyrings were searchable, so we 648 * should consult userspace if we can */ 649 key = ERR_PTR(-ENOKEY); 650 if (!callout_info) 651 goto error_free; 652 653 key = construct_key_and_link(&ctx, callout_info, callout_len, 654 aux, dest_keyring, flags); 655 } 656 657error_free: 658 if (type->match_free) 659 type->match_free(&ctx.match_data); 660error: 661 kleave(" = %p", key); 662 return key; 663} 664 665/** 666 * wait_for_key_construction - Wait for construction of a key to complete 667 * @key: The key being waited for. 668 * @intr: Whether to wait interruptibly. 669 * 670 * Wait for a key to finish being constructed. 671 * 672 * Returns 0 if successful; -ERESTARTSYS if the wait was interrupted; -ENOKEY 673 * if the key was negated; or -EKEYREVOKED or -EKEYEXPIRED if the key was 674 * revoked or expired. 675 */ 676int wait_for_key_construction(struct key *key, bool intr) 677{ 678 int ret; 679 680 ret = wait_on_bit(&key->flags, KEY_FLAG_USER_CONSTRUCT, 681 intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE); 682 if (ret) 683 return -ERESTARTSYS; 684 ret = key_read_state(key); 685 if (ret < 0) 686 return ret; 687 return key_validate(key); 688} 689EXPORT_SYMBOL(wait_for_key_construction); 690 691/** 692 * request_key_tag - Request a key and wait for construction 693 * @type: Type of key. 694 * @description: The searchable description of the key. 695 * @domain_tag: The domain in which the key operates. 696 * @callout_info: The data to pass to the instantiation upcall (or NULL). 697 * 698 * As for request_key_and_link() except that it does not add the returned key 699 * to a keyring if found, new keys are always allocated in the user's quota, 700 * the callout_info must be a NUL-terminated string and no auxiliary data can 701 * be passed. 702 * 703 * Furthermore, it then works as wait_for_key_construction() to wait for the 704 * completion of keys undergoing construction with a non-interruptible wait. 705 */ 706struct key *request_key_tag(struct key_type *type, 707 const char *description, 708 struct key_tag *domain_tag, 709 const char *callout_info) 710{ 711 struct key *key; 712 size_t callout_len = 0; 713 int ret; 714 715 if (callout_info) 716 callout_len = strlen(callout_info); 717 key = request_key_and_link(type, description, domain_tag, 718 callout_info, callout_len, 719 NULL, NULL, KEY_ALLOC_IN_QUOTA); 720 if (!IS_ERR(key)) { 721 ret = wait_for_key_construction(key, false); 722 if (ret < 0) { 723 key_put(key); 724 return ERR_PTR(ret); 725 } 726 } 727 return key; 728} 729EXPORT_SYMBOL(request_key_tag); 730 731/** 732 * request_key_with_auxdata - Request a key with auxiliary data for the upcaller 733 * @type: The type of key we want. 734 * @description: The searchable description of the key. 735 * @domain_tag: The domain in which the key operates. 736 * @callout_info: The data to pass to the instantiation upcall (or NULL). 737 * @callout_len: The length of callout_info. 738 * @aux: Auxiliary data for the upcall. 739 * 740 * As for request_key_and_link() except that it does not add the returned key 741 * to a keyring if found and new keys are always allocated in the user's quota. 742 * 743 * Furthermore, it then works as wait_for_key_construction() to wait for the 744 * completion of keys undergoing construction with a non-interruptible wait. 745 */ 746struct key *request_key_with_auxdata(struct key_type *type, 747 const char *description, 748 struct key_tag *domain_tag, 749 const void *callout_info, 750 size_t callout_len, 751 void *aux) 752{ 753 struct key *key; 754 int ret; 755 756 key = request_key_and_link(type, description, domain_tag, 757 callout_info, callout_len, 758 aux, NULL, KEY_ALLOC_IN_QUOTA); 759 if (!IS_ERR(key)) { 760 ret = wait_for_key_construction(key, false); 761 if (ret < 0) { 762 key_put(key); 763 return ERR_PTR(ret); 764 } 765 } 766 return key; 767} 768EXPORT_SYMBOL(request_key_with_auxdata); 769 770/** 771 * request_key_rcu - Request key from RCU-read-locked context 772 * @type: The type of key we want. 773 * @description: The name of the key we want. 774 * @domain_tag: The domain in which the key operates. 775 * 776 * Request a key from a context that we may not sleep in (such as RCU-mode 777 * pathwalk). Keys under construction are ignored. 778 * 779 * Return a pointer to the found key if successful, -ENOKEY if we couldn't find 780 * a key or some other error if the key found was unsuitable or inaccessible. 781 */ 782struct key *request_key_rcu(struct key_type *type, 783 const char *description, 784 struct key_tag *domain_tag) 785{ 786 struct keyring_search_context ctx = { 787 .index_key.type = type, 788 .index_key.domain_tag = domain_tag, 789 .index_key.description = description, 790 .index_key.desc_len = strlen(description), 791 .cred = current_cred(), 792 .match_data.cmp = key_default_cmp, 793 .match_data.raw_data = description, 794 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, 795 .flags = (KEYRING_SEARCH_DO_STATE_CHECK | 796 KEYRING_SEARCH_SKIP_EXPIRED), 797 }; 798 struct key *key; 799 key_ref_t key_ref; 800 801 kenter("%s,%s", type->name, description); 802 803 key = check_cached_key(&ctx); 804 if (key) 805 return key; 806 807 /* search all the process keyrings for a key */ 808 key_ref = search_process_keyrings_rcu(&ctx); 809 if (IS_ERR(key_ref)) { 810 key = ERR_CAST(key_ref); 811 if (PTR_ERR(key_ref) == -EAGAIN) 812 key = ERR_PTR(-ENOKEY); 813 } else { 814 key = key_ref_to_ptr(key_ref); 815 cache_requested_key(key); 816 } 817 818 kleave(" = %p", key); 819 return key; 820} 821EXPORT_SYMBOL(request_key_rcu); 822