security/keys/request_key.c

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