linux/security/keys/keyctl.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/* Userspace key control operations
   3 *
   4 * Copyright (C) 2004-5 Red Hat, Inc. All Rights Reserved.
   5 * Written by David Howells (dhowells@redhat.com)
   6 */
   7
   8#include <linux/init.h>
   9#include <linux/sched.h>
  10#include <linux/sched/task.h>
  11#include <linux/slab.h>
  12#include <linux/syscalls.h>
  13#include <linux/key.h>
  14#include <linux/keyctl.h>
  15#include <linux/fs.h>
  16#include <linux/capability.h>
  17#include <linux/cred.h>
  18#include <linux/string.h>
  19#include <linux/err.h>
  20#include <linux/vmalloc.h>
  21#include <linux/security.h>
  22#include <linux/uio.h>
  23#include <linux/uaccess.h>
  24#include <keys/request_key_auth-type.h>
  25#include "internal.h"
  26
  27#define KEY_MAX_DESC_SIZE 4096
  28
  29static const unsigned char keyrings_capabilities[2] = {
  30        [0] = (KEYCTL_CAPS0_CAPABILITIES |
  31               (IS_ENABLED(CONFIG_PERSISTENT_KEYRINGS)  ? KEYCTL_CAPS0_PERSISTENT_KEYRINGS : 0) |
  32               (IS_ENABLED(CONFIG_KEY_DH_OPERATIONS)    ? KEYCTL_CAPS0_DIFFIE_HELLMAN : 0) |
  33               (IS_ENABLED(CONFIG_ASYMMETRIC_KEY_TYPE)  ? KEYCTL_CAPS0_PUBLIC_KEY : 0) |
  34               (IS_ENABLED(CONFIG_BIG_KEYS)             ? KEYCTL_CAPS0_BIG_KEY : 0) |
  35               KEYCTL_CAPS0_INVALIDATE |
  36               KEYCTL_CAPS0_RESTRICT_KEYRING |
  37               KEYCTL_CAPS0_MOVE
  38               ),
  39        [1] = (KEYCTL_CAPS1_NS_KEYRING_NAME |
  40               KEYCTL_CAPS1_NS_KEY_TAG |
  41               (IS_ENABLED(CONFIG_KEY_NOTIFICATIONS)    ? KEYCTL_CAPS1_NOTIFICATIONS : 0)
  42               ),
  43};
  44
  45static int key_get_type_from_user(char *type,
  46                                  const char __user *_type,
  47                                  unsigned len)
  48{
  49        int ret;
  50
  51        ret = strncpy_from_user(type, _type, len);
  52        if (ret < 0)
  53                return ret;
  54        if (ret == 0 || ret >= len)
  55                return -EINVAL;
  56        if (type[0] == '.')
  57                return -EPERM;
  58        type[len - 1] = '\0';
  59        return 0;
  60}
  61
  62/*
  63 * Extract the description of a new key from userspace and either add it as a
  64 * new key to the specified keyring or update a matching key in that keyring.
  65 *
  66 * If the description is NULL or an empty string, the key type is asked to
  67 * generate one from the payload.
  68 *
  69 * The keyring must be writable so that we can attach the key to it.
  70 *
  71 * If successful, the new key's serial number is returned, otherwise an error
  72 * code is returned.
  73 */
  74SYSCALL_DEFINE5(add_key, const char __user *, _type,
  75                const char __user *, _description,
  76                const void __user *, _payload,
  77                size_t, plen,
  78                key_serial_t, ringid)
  79{
  80        key_ref_t keyring_ref, key_ref;
  81        char type[32], *description;
  82        void *payload;
  83        long ret;
  84
  85        ret = -EINVAL;
  86        if (plen > 1024 * 1024 - 1)
  87                goto error;
  88
  89        /* draw all the data into kernel space */
  90        ret = key_get_type_from_user(type, _type, sizeof(type));
  91        if (ret < 0)
  92                goto error;
  93
  94        description = NULL;
  95        if (_description) {
  96                description = strndup_user(_description, KEY_MAX_DESC_SIZE);
  97                if (IS_ERR(description)) {
  98                        ret = PTR_ERR(description);
  99                        goto error;
 100                }
 101                if (!*description) {
 102                        kfree(description);
 103                        description = NULL;
 104                } else if ((description[0] == '.') &&
 105                           (strncmp(type, "keyring", 7) == 0)) {
 106                        ret = -EPERM;
 107                        goto error2;
 108                }
 109        }
 110
 111        /* pull the payload in if one was supplied */
 112        payload = NULL;
 113
 114        if (plen) {
 115                ret = -ENOMEM;
 116                payload = kvmalloc(plen, GFP_KERNEL);
 117                if (!payload)
 118                        goto error2;
 119
 120                ret = -EFAULT;
 121                if (copy_from_user(payload, _payload, plen) != 0)
 122                        goto error3;
 123        }
 124
 125        /* find the target keyring (which must be writable) */
 126        keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 127        if (IS_ERR(keyring_ref)) {
 128                ret = PTR_ERR(keyring_ref);
 129                goto error3;
 130        }
 131
 132        /* create or update the requested key and add it to the target
 133         * keyring */
 134        key_ref = key_create_or_update(keyring_ref, type, description,
 135                                       payload, plen, KEY_PERM_UNDEF,
 136                                       KEY_ALLOC_IN_QUOTA);
 137        if (!IS_ERR(key_ref)) {
 138                ret = key_ref_to_ptr(key_ref)->serial;
 139                key_ref_put(key_ref);
 140        }
 141        else {
 142                ret = PTR_ERR(key_ref);
 143        }
 144
 145        key_ref_put(keyring_ref);
 146 error3:
 147        kvfree_sensitive(payload, plen);
 148 error2:
 149        kfree(description);
 150 error:
 151        return ret;
 152}
 153
 154/*
 155 * Search the process keyrings and keyring trees linked from those for a
 156 * matching key.  Keyrings must have appropriate Search permission to be
 157 * searched.
 158 *
 159 * If a key is found, it will be attached to the destination keyring if there's
 160 * one specified and the serial number of the key will be returned.
 161 *
 162 * If no key is found, /sbin/request-key will be invoked if _callout_info is
 163 * non-NULL in an attempt to create a key.  The _callout_info string will be
 164 * passed to /sbin/request-key to aid with completing the request.  If the
 165 * _callout_info string is "" then it will be changed to "-".
 166 */
 167SYSCALL_DEFINE4(request_key, const char __user *, _type,
 168                const char __user *, _description,
 169                const char __user *, _callout_info,
 170                key_serial_t, destringid)
 171{
 172        struct key_type *ktype;
 173        struct key *key;
 174        key_ref_t dest_ref;
 175        size_t callout_len;
 176        char type[32], *description, *callout_info;
 177        long ret;
 178
 179        /* pull the type into kernel space */
 180        ret = key_get_type_from_user(type, _type, sizeof(type));
 181        if (ret < 0)
 182                goto error;
 183
 184        /* pull the description into kernel space */
 185        description = strndup_user(_description, KEY_MAX_DESC_SIZE);
 186        if (IS_ERR(description)) {
 187                ret = PTR_ERR(description);
 188                goto error;
 189        }
 190
 191        /* pull the callout info into kernel space */
 192        callout_info = NULL;
 193        callout_len = 0;
 194        if (_callout_info) {
 195                callout_info = strndup_user(_callout_info, PAGE_SIZE);
 196                if (IS_ERR(callout_info)) {
 197                        ret = PTR_ERR(callout_info);
 198                        goto error2;
 199                }
 200                callout_len = strlen(callout_info);
 201        }
 202
 203        /* get the destination keyring if specified */
 204        dest_ref = NULL;
 205        if (destringid) {
 206                dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 207                                           KEY_NEED_WRITE);
 208                if (IS_ERR(dest_ref)) {
 209                        ret = PTR_ERR(dest_ref);
 210                        goto error3;
 211                }
 212        }
 213
 214        /* find the key type */
 215        ktype = key_type_lookup(type);
 216        if (IS_ERR(ktype)) {
 217                ret = PTR_ERR(ktype);
 218                goto error4;
 219        }
 220
 221        /* do the search */
 222        key = request_key_and_link(ktype, description, NULL, callout_info,
 223                                   callout_len, NULL, key_ref_to_ptr(dest_ref),
 224                                   KEY_ALLOC_IN_QUOTA);
 225        if (IS_ERR(key)) {
 226                ret = PTR_ERR(key);
 227                goto error5;
 228        }
 229
 230        /* wait for the key to finish being constructed */
 231        ret = wait_for_key_construction(key, 1);
 232        if (ret < 0)
 233                goto error6;
 234
 235        ret = key->serial;
 236
 237error6:
 238        key_put(key);
 239error5:
 240        key_type_put(ktype);
 241error4:
 242        key_ref_put(dest_ref);
 243error3:
 244        kfree(callout_info);
 245error2:
 246        kfree(description);
 247error:
 248        return ret;
 249}
 250
 251/*
 252 * Get the ID of the specified process keyring.
 253 *
 254 * The requested keyring must have search permission to be found.
 255 *
 256 * If successful, the ID of the requested keyring will be returned.
 257 */
 258long keyctl_get_keyring_ID(key_serial_t id, int create)
 259{
 260        key_ref_t key_ref;
 261        unsigned long lflags;
 262        long ret;
 263
 264        lflags = create ? KEY_LOOKUP_CREATE : 0;
 265        key_ref = lookup_user_key(id, lflags, KEY_NEED_SEARCH);
 266        if (IS_ERR(key_ref)) {
 267                ret = PTR_ERR(key_ref);
 268                goto error;
 269        }
 270
 271        ret = key_ref_to_ptr(key_ref)->serial;
 272        key_ref_put(key_ref);
 273error:
 274        return ret;
 275}
 276
 277/*
 278 * Join a (named) session keyring.
 279 *
 280 * Create and join an anonymous session keyring or join a named session
 281 * keyring, creating it if necessary.  A named session keyring must have Search
 282 * permission for it to be joined.  Session keyrings without this permit will
 283 * be skipped over.  It is not permitted for userspace to create or join
 284 * keyrings whose name begin with a dot.
 285 *
 286 * If successful, the ID of the joined session keyring will be returned.
 287 */
 288long keyctl_join_session_keyring(const char __user *_name)
 289{
 290        char *name;
 291        long ret;
 292
 293        /* fetch the name from userspace */
 294        name = NULL;
 295        if (_name) {
 296                name = strndup_user(_name, KEY_MAX_DESC_SIZE);
 297                if (IS_ERR(name)) {
 298                        ret = PTR_ERR(name);
 299                        goto error;
 300                }
 301
 302                ret = -EPERM;
 303                if (name[0] == '.')
 304                        goto error_name;
 305        }
 306
 307        /* join the session */
 308        ret = join_session_keyring(name);
 309error_name:
 310        kfree(name);
 311error:
 312        return ret;
 313}
 314
 315/*
 316 * Update a key's data payload from the given data.
 317 *
 318 * The key must grant the caller Write permission and the key type must support
 319 * updating for this to work.  A negative key can be positively instantiated
 320 * with this call.
 321 *
 322 * If successful, 0 will be returned.  If the key type does not support
 323 * updating, then -EOPNOTSUPP will be returned.
 324 */
 325long keyctl_update_key(key_serial_t id,
 326                       const void __user *_payload,
 327                       size_t plen)
 328{
 329        key_ref_t key_ref;
 330        void *payload;
 331        long ret;
 332
 333        ret = -EINVAL;
 334        if (plen > PAGE_SIZE)
 335                goto error;
 336
 337        /* pull the payload in if one was supplied */
 338        payload = NULL;
 339        if (plen) {
 340                ret = -ENOMEM;
 341                payload = kvmalloc(plen, GFP_KERNEL);
 342                if (!payload)
 343                        goto error;
 344
 345                ret = -EFAULT;
 346                if (copy_from_user(payload, _payload, plen) != 0)
 347                        goto error2;
 348        }
 349
 350        /* find the target key (which must be writable) */
 351        key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 352        if (IS_ERR(key_ref)) {
 353                ret = PTR_ERR(key_ref);
 354                goto error2;
 355        }
 356
 357        /* update the key */
 358        ret = key_update(key_ref, payload, plen);
 359
 360        key_ref_put(key_ref);
 361error2:
 362        kvfree_sensitive(payload, plen);
 363error:
 364        return ret;
 365}
 366
 367/*
 368 * Revoke a key.
 369 *
 370 * The key must be grant the caller Write or Setattr permission for this to
 371 * work.  The key type should give up its quota claim when revoked.  The key
 372 * and any links to the key will be automatically garbage collected after a
 373 * certain amount of time (/proc/sys/kernel/keys/gc_delay).
 374 *
 375 * Keys with KEY_FLAG_KEEP set should not be revoked.
 376 *
 377 * If successful, 0 is returned.
 378 */
 379long keyctl_revoke_key(key_serial_t id)
 380{
 381        key_ref_t key_ref;
 382        struct key *key;
 383        long ret;
 384
 385        key_ref = lookup_user_key(id, 0, KEY_NEED_WRITE);
 386        if (IS_ERR(key_ref)) {
 387                ret = PTR_ERR(key_ref);
 388                if (ret != -EACCES)
 389                        goto error;
 390                key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
 391                if (IS_ERR(key_ref)) {
 392                        ret = PTR_ERR(key_ref);
 393                        goto error;
 394                }
 395        }
 396
 397        key = key_ref_to_ptr(key_ref);
 398        ret = 0;
 399        if (test_bit(KEY_FLAG_KEEP, &key->flags))
 400                ret = -EPERM;
 401        else
 402                key_revoke(key);
 403
 404        key_ref_put(key_ref);
 405error:
 406        return ret;
 407}
 408
 409/*
 410 * Invalidate a key.
 411 *
 412 * The key must be grant the caller Invalidate permission for this to work.
 413 * The key and any links to the key will be automatically garbage collected
 414 * immediately.
 415 *
 416 * Keys with KEY_FLAG_KEEP set should not be invalidated.
 417 *
 418 * If successful, 0 is returned.
 419 */
 420long keyctl_invalidate_key(key_serial_t id)
 421{
 422        key_ref_t key_ref;
 423        struct key *key;
 424        long ret;
 425
 426        kenter("%d", id);
 427
 428        key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
 429        if (IS_ERR(key_ref)) {
 430                ret = PTR_ERR(key_ref);
 431
 432                /* Root is permitted to invalidate certain special keys */
 433                if (capable(CAP_SYS_ADMIN)) {
 434                        key_ref = lookup_user_key(id, 0, KEY_SYSADMIN_OVERRIDE);
 435                        if (IS_ERR(key_ref))
 436                                goto error;
 437                        if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
 438                                     &key_ref_to_ptr(key_ref)->flags))
 439                                goto invalidate;
 440                        goto error_put;
 441                }
 442
 443                goto error;
 444        }
 445
 446invalidate:
 447        key = key_ref_to_ptr(key_ref);
 448        ret = 0;
 449        if (test_bit(KEY_FLAG_KEEP, &key->flags))
 450                ret = -EPERM;
 451        else
 452                key_invalidate(key);
 453error_put:
 454        key_ref_put(key_ref);
 455error:
 456        kleave(" = %ld", ret);
 457        return ret;
 458}
 459
 460/*
 461 * Clear the specified keyring, creating an empty process keyring if one of the
 462 * special keyring IDs is used.
 463 *
 464 * The keyring must grant the caller Write permission and not have
 465 * KEY_FLAG_KEEP set for this to work.  If successful, 0 will be returned.
 466 */
 467long keyctl_keyring_clear(key_serial_t ringid)
 468{
 469        key_ref_t keyring_ref;
 470        struct key *keyring;
 471        long ret;
 472
 473        keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 474        if (IS_ERR(keyring_ref)) {
 475                ret = PTR_ERR(keyring_ref);
 476
 477                /* Root is permitted to invalidate certain special keyrings */
 478                if (capable(CAP_SYS_ADMIN)) {
 479                        keyring_ref = lookup_user_key(ringid, 0,
 480                                                      KEY_SYSADMIN_OVERRIDE);
 481                        if (IS_ERR(keyring_ref))
 482                                goto error;
 483                        if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR,
 484                                     &key_ref_to_ptr(keyring_ref)->flags))
 485                                goto clear;
 486                        goto error_put;
 487                }
 488
 489                goto error;
 490        }
 491
 492clear:
 493        keyring = key_ref_to_ptr(keyring_ref);
 494        if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
 495                ret = -EPERM;
 496        else
 497                ret = keyring_clear(keyring);
 498error_put:
 499        key_ref_put(keyring_ref);
 500error:
 501        return ret;
 502}
 503
 504/*
 505 * Create a link from a keyring to a key if there's no matching key in the
 506 * keyring, otherwise replace the link to the matching key with a link to the
 507 * new key.
 508 *
 509 * The key must grant the caller Link permission and the keyring must grant
 510 * the caller Write permission.  Furthermore, if an additional link is created,
 511 * the keyring's quota will be extended.
 512 *
 513 * If successful, 0 will be returned.
 514 */
 515long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
 516{
 517        key_ref_t keyring_ref, key_ref;
 518        long ret;
 519
 520        keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 521        if (IS_ERR(keyring_ref)) {
 522                ret = PTR_ERR(keyring_ref);
 523                goto error;
 524        }
 525
 526        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
 527        if (IS_ERR(key_ref)) {
 528                ret = PTR_ERR(key_ref);
 529                goto error2;
 530        }
 531
 532        ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref));
 533
 534        key_ref_put(key_ref);
 535error2:
 536        key_ref_put(keyring_ref);
 537error:
 538        return ret;
 539}
 540
 541/*
 542 * Unlink a key from a keyring.
 543 *
 544 * The keyring must grant the caller Write permission for this to work; the key
 545 * itself need not grant the caller anything.  If the last link to a key is
 546 * removed then that key will be scheduled for destruction.
 547 *
 548 * Keys or keyrings with KEY_FLAG_KEEP set should not be unlinked.
 549 *
 550 * If successful, 0 will be returned.
 551 */
 552long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
 553{
 554        key_ref_t keyring_ref, key_ref;
 555        struct key *keyring, *key;
 556        long ret;
 557
 558        keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_WRITE);
 559        if (IS_ERR(keyring_ref)) {
 560                ret = PTR_ERR(keyring_ref);
 561                goto error;
 562        }
 563
 564        key_ref = lookup_user_key(id, KEY_LOOKUP_PARTIAL, KEY_NEED_UNLINK);
 565        if (IS_ERR(key_ref)) {
 566                ret = PTR_ERR(key_ref);
 567                goto error2;
 568        }
 569
 570        keyring = key_ref_to_ptr(keyring_ref);
 571        key = key_ref_to_ptr(key_ref);
 572        if (test_bit(KEY_FLAG_KEEP, &keyring->flags) &&
 573            test_bit(KEY_FLAG_KEEP, &key->flags))
 574                ret = -EPERM;
 575        else
 576                ret = key_unlink(keyring, key);
 577
 578        key_ref_put(key_ref);
 579error2:
 580        key_ref_put(keyring_ref);
 581error:
 582        return ret;
 583}
 584
 585/*
 586 * Move a link to a key from one keyring to another, displacing any matching
 587 * key from the destination keyring.
 588 *
 589 * The key must grant the caller Link permission and both keyrings must grant
 590 * the caller Write permission.  There must also be a link in the from keyring
 591 * to the key.  If both keyrings are the same, nothing is done.
 592 *
 593 * If successful, 0 will be returned.
 594 */
 595long keyctl_keyring_move(key_serial_t id, key_serial_t from_ringid,
 596                         key_serial_t to_ringid, unsigned int flags)
 597{
 598        key_ref_t key_ref, from_ref, to_ref;
 599        long ret;
 600
 601        if (flags & ~KEYCTL_MOVE_EXCL)
 602                return -EINVAL;
 603
 604        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_LINK);
 605        if (IS_ERR(key_ref))
 606                return PTR_ERR(key_ref);
 607
 608        from_ref = lookup_user_key(from_ringid, 0, KEY_NEED_WRITE);
 609        if (IS_ERR(from_ref)) {
 610                ret = PTR_ERR(from_ref);
 611                goto error2;
 612        }
 613
 614        to_ref = lookup_user_key(to_ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
 615        if (IS_ERR(to_ref)) {
 616                ret = PTR_ERR(to_ref);
 617                goto error3;
 618        }
 619
 620        ret = key_move(key_ref_to_ptr(key_ref), key_ref_to_ptr(from_ref),
 621                       key_ref_to_ptr(to_ref), flags);
 622
 623        key_ref_put(to_ref);
 624error3:
 625        key_ref_put(from_ref);
 626error2:
 627        key_ref_put(key_ref);
 628        return ret;
 629}
 630
 631/*
 632 * Return a description of a key to userspace.
 633 *
 634 * The key must grant the caller View permission for this to work.
 635 *
 636 * If there's a buffer, we place up to buflen bytes of data into it formatted
 637 * in the following way:
 638 *
 639 *      type;uid;gid;perm;description<NUL>
 640 *
 641 * If successful, we return the amount of description available, irrespective
 642 * of how much we may have copied into the buffer.
 643 */
 644long keyctl_describe_key(key_serial_t keyid,
 645                         char __user *buffer,
 646                         size_t buflen)
 647{
 648        struct key *key, *instkey;
 649        key_ref_t key_ref;
 650        char *infobuf;
 651        long ret;
 652        int desclen, infolen;
 653
 654        key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
 655        if (IS_ERR(key_ref)) {
 656                /* viewing a key under construction is permitted if we have the
 657                 * authorisation token handy */
 658                if (PTR_ERR(key_ref) == -EACCES) {
 659                        instkey = key_get_instantiation_authkey(keyid);
 660                        if (!IS_ERR(instkey)) {
 661                                key_put(instkey);
 662                                key_ref = lookup_user_key(keyid,
 663                                                          KEY_LOOKUP_PARTIAL,
 664                                                          KEY_AUTHTOKEN_OVERRIDE);
 665                                if (!IS_ERR(key_ref))
 666                                        goto okay;
 667                        }
 668                }
 669
 670                ret = PTR_ERR(key_ref);
 671                goto error;
 672        }
 673
 674okay:
 675        key = key_ref_to_ptr(key_ref);
 676        desclen = strlen(key->description);
 677
 678        /* calculate how much information we're going to return */
 679        ret = -ENOMEM;
 680        infobuf = kasprintf(GFP_KERNEL,
 681                            "%s;%d;%d;%08x;",
 682                            key->type->name,
 683                            from_kuid_munged(current_user_ns(), key->uid),
 684                            from_kgid_munged(current_user_ns(), key->gid),
 685                            key->perm);
 686        if (!infobuf)
 687                goto error2;
 688        infolen = strlen(infobuf);
 689        ret = infolen + desclen + 1;
 690
 691        /* consider returning the data */
 692        if (buffer && buflen >= ret) {
 693                if (copy_to_user(buffer, infobuf, infolen) != 0 ||
 694                    copy_to_user(buffer + infolen, key->description,
 695                                 desclen + 1) != 0)
 696                        ret = -EFAULT;
 697        }
 698
 699        kfree(infobuf);
 700error2:
 701        key_ref_put(key_ref);
 702error:
 703        return ret;
 704}
 705
 706/*
 707 * Search the specified keyring and any keyrings it links to for a matching
 708 * key.  Only keyrings that grant the caller Search permission will be searched
 709 * (this includes the starting keyring).  Only keys with Search permission can
 710 * be found.
 711 *
 712 * If successful, the found key will be linked to the destination keyring if
 713 * supplied and the key has Link permission, and the found key ID will be
 714 * returned.
 715 */
 716long keyctl_keyring_search(key_serial_t ringid,
 717                           const char __user *_type,
 718                           const char __user *_description,
 719                           key_serial_t destringid)
 720{
 721        struct key_type *ktype;
 722        key_ref_t keyring_ref, key_ref, dest_ref;
 723        char type[32], *description;
 724        long ret;
 725
 726        /* pull the type and description into kernel space */
 727        ret = key_get_type_from_user(type, _type, sizeof(type));
 728        if (ret < 0)
 729                goto error;
 730
 731        description = strndup_user(_description, KEY_MAX_DESC_SIZE);
 732        if (IS_ERR(description)) {
 733                ret = PTR_ERR(description);
 734                goto error;
 735        }
 736
 737        /* get the keyring at which to begin the search */
 738        keyring_ref = lookup_user_key(ringid, 0, KEY_NEED_SEARCH);
 739        if (IS_ERR(keyring_ref)) {
 740                ret = PTR_ERR(keyring_ref);
 741                goto error2;
 742        }
 743
 744        /* get the destination keyring if specified */
 745        dest_ref = NULL;
 746        if (destringid) {
 747                dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE,
 748                                           KEY_NEED_WRITE);
 749                if (IS_ERR(dest_ref)) {
 750                        ret = PTR_ERR(dest_ref);
 751                        goto error3;
 752                }
 753        }
 754
 755        /* find the key type */
 756        ktype = key_type_lookup(type);
 757        if (IS_ERR(ktype)) {
 758                ret = PTR_ERR(ktype);
 759                goto error4;
 760        }
 761
 762        /* do the search */
 763        key_ref = keyring_search(keyring_ref, ktype, description, true);
 764        if (IS_ERR(key_ref)) {
 765                ret = PTR_ERR(key_ref);
 766
 767                /* treat lack or presence of a negative key the same */
 768                if (ret == -EAGAIN)
 769                        ret = -ENOKEY;
 770                goto error5;
 771        }
 772
 773        /* link the resulting key to the destination keyring if we can */
 774        if (dest_ref) {
 775                ret = key_permission(key_ref, KEY_NEED_LINK);
 776                if (ret < 0)
 777                        goto error6;
 778
 779                ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref));
 780                if (ret < 0)
 781                        goto error6;
 782        }
 783
 784        ret = key_ref_to_ptr(key_ref)->serial;
 785
 786error6:
 787        key_ref_put(key_ref);
 788error5:
 789        key_type_put(ktype);
 790error4:
 791        key_ref_put(dest_ref);
 792error3:
 793        key_ref_put(keyring_ref);
 794error2:
 795        kfree(description);
 796error:
 797        return ret;
 798}
 799
 800/*
 801 * Call the read method
 802 */
 803static long __keyctl_read_key(struct key *key, char *buffer, size_t buflen)
 804{
 805        long ret;
 806
 807        down_read(&key->sem);
 808        ret = key_validate(key);
 809        if (ret == 0)
 810                ret = key->type->read(key, buffer, buflen);
 811        up_read(&key->sem);
 812        return ret;
 813}
 814
 815/*
 816 * Read a key's payload.
 817 *
 818 * The key must either grant the caller Read permission, or it must grant the
 819 * caller Search permission when searched for from the process keyrings.
 820 *
 821 * If successful, we place up to buflen bytes of data into the buffer, if one
 822 * is provided, and return the amount of data that is available in the key,
 823 * irrespective of how much we copied into the buffer.
 824 */
 825long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
 826{
 827        struct key *key;
 828        key_ref_t key_ref;
 829        long ret;
 830        char *key_data = NULL;
 831        size_t key_data_len;
 832
 833        /* find the key first */
 834        key_ref = lookup_user_key(keyid, 0, KEY_DEFER_PERM_CHECK);
 835        if (IS_ERR(key_ref)) {
 836                ret = -ENOKEY;
 837                goto out;
 838        }
 839
 840        key = key_ref_to_ptr(key_ref);
 841
 842        ret = key_read_state(key);
 843        if (ret < 0)
 844                goto key_put_out; /* Negatively instantiated */
 845
 846        /* see if we can read it directly */
 847        ret = key_permission(key_ref, KEY_NEED_READ);
 848        if (ret == 0)
 849                goto can_read_key;
 850        if (ret != -EACCES)
 851                goto key_put_out;
 852
 853        /* we can't; see if it's searchable from this process's keyrings
 854         * - we automatically take account of the fact that it may be
 855         *   dangling off an instantiation key
 856         */
 857        if (!is_key_possessed(key_ref)) {
 858                ret = -EACCES;
 859                goto key_put_out;
 860        }
 861
 862        /* the key is probably readable - now try to read it */
 863can_read_key:
 864        if (!key->type->read) {
 865                ret = -EOPNOTSUPP;
 866                goto key_put_out;
 867        }
 868
 869        if (!buffer || !buflen) {
 870                /* Get the key length from the read method */
 871                ret = __keyctl_read_key(key, NULL, 0);
 872                goto key_put_out;
 873        }
 874
 875        /*
 876         * Read the data with the semaphore held (since we might sleep)
 877         * to protect against the key being updated or revoked.
 878         *
 879         * Allocating a temporary buffer to hold the keys before
 880         * transferring them to user buffer to avoid potential
 881         * deadlock involving page fault and mmap_lock.
 882         *
 883         * key_data_len = (buflen <= PAGE_SIZE)
 884         *              ? buflen : actual length of key data
 885         *
 886         * This prevents allocating arbitrary large buffer which can
 887         * be much larger than the actual key length. In the latter case,
 888         * at least 2 passes of this loop is required.
 889         */
 890        key_data_len = (buflen <= PAGE_SIZE) ? buflen : 0;
 891        for (;;) {
 892                if (key_data_len) {
 893                        key_data = kvmalloc(key_data_len, GFP_KERNEL);
 894                        if (!key_data) {
 895                                ret = -ENOMEM;
 896                                goto key_put_out;
 897                        }
 898                }
 899
 900                ret = __keyctl_read_key(key, key_data, key_data_len);
 901
 902                /*
 903                 * Read methods will just return the required length without
 904                 * any copying if the provided length isn't large enough.
 905                 */
 906                if (ret <= 0 || ret > buflen)
 907                        break;
 908
 909                /*
 910                 * The key may change (unlikely) in between 2 consecutive
 911                 * __keyctl_read_key() calls. In this case, we reallocate
 912                 * a larger buffer and redo the key read when
 913                 * key_data_len < ret <= buflen.
 914                 */
 915                if (ret > key_data_len) {
 916                        if (unlikely(key_data))
 917                                kvfree_sensitive(key_data, key_data_len);
 918                        key_data_len = ret;
 919                        continue;       /* Allocate buffer */
 920                }
 921
 922                if (copy_to_user(buffer, key_data, ret))
 923                        ret = -EFAULT;
 924                break;
 925        }
 926        kvfree_sensitive(key_data, key_data_len);
 927
 928key_put_out:
 929        key_put(key);
 930out:
 931        return ret;
 932}
 933
 934/*
 935 * Change the ownership of a key
 936 *
 937 * The key must grant the caller Setattr permission for this to work, though
 938 * the key need not be fully instantiated yet.  For the UID to be changed, or
 939 * for the GID to be changed to a group the caller is not a member of, the
 940 * caller must have sysadmin capability.  If either uid or gid is -1 then that
 941 * attribute is not changed.
 942 *
 943 * If the UID is to be changed, the new user must have sufficient quota to
 944 * accept the key.  The quota deduction will be removed from the old user to
 945 * the new user should the attribute be changed.
 946 *
 947 * If successful, 0 will be returned.
 948 */
 949long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group)
 950{
 951        struct key_user *newowner, *zapowner = NULL;
 952        struct key *key;
 953        key_ref_t key_ref;
 954        long ret;
 955        kuid_t uid;
 956        kgid_t gid;
 957
 958        uid = make_kuid(current_user_ns(), user);
 959        gid = make_kgid(current_user_ns(), group);
 960        ret = -EINVAL;
 961        if ((user != (uid_t) -1) && !uid_valid(uid))
 962                goto error;
 963        if ((group != (gid_t) -1) && !gid_valid(gid))
 964                goto error;
 965
 966        ret = 0;
 967        if (user == (uid_t) -1 && group == (gid_t) -1)
 968                goto error;
 969
 970        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
 971                                  KEY_NEED_SETATTR);
 972        if (IS_ERR(key_ref)) {
 973                ret = PTR_ERR(key_ref);
 974                goto error;
 975        }
 976
 977        key = key_ref_to_ptr(key_ref);
 978
 979        /* make the changes with the locks held to prevent chown/chown races */
 980        ret = -EACCES;
 981        down_write(&key->sem);
 982
 983        if (!capable(CAP_SYS_ADMIN)) {
 984                /* only the sysadmin can chown a key to some other UID */
 985                if (user != (uid_t) -1 && !uid_eq(key->uid, uid))
 986                        goto error_put;
 987
 988                /* only the sysadmin can set the key's GID to a group other
 989                 * than one of those that the current process subscribes to */
 990                if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid))
 991                        goto error_put;
 992        }
 993
 994        /* change the UID */
 995        if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) {
 996                ret = -ENOMEM;
 997                newowner = key_user_lookup(uid);
 998                if (!newowner)
 999                        goto error_put;
1000
1001                /* transfer the quota burden to the new user */
1002                if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
1003                        unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ?
1004                                key_quota_root_maxkeys : key_quota_maxkeys;
1005                        unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ?
1006                                key_quota_root_maxbytes : key_quota_maxbytes;
1007
1008                        spin_lock(&newowner->lock);
1009                        if (newowner->qnkeys + 1 > maxkeys ||
1010                            newowner->qnbytes + key->quotalen > maxbytes ||
1011                            newowner->qnbytes + key->quotalen <
1012                            newowner->qnbytes)
1013                                goto quota_overrun;
1014
1015                        newowner->qnkeys++;
1016                        newowner->qnbytes += key->quotalen;
1017                        spin_unlock(&newowner->lock);
1018
1019                        spin_lock(&key->user->lock);
1020                        key->user->qnkeys--;
1021                        key->user->qnbytes -= key->quotalen;
1022                        spin_unlock(&key->user->lock);
1023                }
1024
1025                atomic_dec(&key->user->nkeys);
1026                atomic_inc(&newowner->nkeys);
1027
1028                if (key->state != KEY_IS_UNINSTANTIATED) {
1029                        atomic_dec(&key->user->nikeys);
1030                        atomic_inc(&newowner->nikeys);
1031                }
1032
1033                zapowner = key->user;
1034                key->user = newowner;
1035                key->uid = uid;
1036        }
1037
1038        /* change the GID */
1039        if (group != (gid_t) -1)
1040                key->gid = gid;
1041
1042        notify_key(key, NOTIFY_KEY_SETATTR, 0);
1043        ret = 0;
1044
1045error_put:
1046        up_write(&key->sem);
1047        key_put(key);
1048        if (zapowner)
1049                key_user_put(zapowner);
1050error:
1051        return ret;
1052
1053quota_overrun:
1054        spin_unlock(&newowner->lock);
1055        zapowner = newowner;
1056        ret = -EDQUOT;
1057        goto error_put;
1058}
1059
1060/*
1061 * Change the permission mask on a key.
1062 *
1063 * The key must grant the caller Setattr permission for this to work, though
1064 * the key need not be fully instantiated yet.  If the caller does not have
1065 * sysadmin capability, it may only change the permission on keys that it owns.
1066 */
1067long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
1068{
1069        struct key *key;
1070        key_ref_t key_ref;
1071        long ret;
1072
1073        ret = -EINVAL;
1074        if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
1075                goto error;
1076
1077        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1078                                  KEY_NEED_SETATTR);
1079        if (IS_ERR(key_ref)) {
1080                ret = PTR_ERR(key_ref);
1081                goto error;
1082        }
1083
1084        key = key_ref_to_ptr(key_ref);
1085
1086        /* make the changes with the locks held to prevent chown/chmod races */
1087        ret = -EACCES;
1088        down_write(&key->sem);
1089
1090        /* if we're not the sysadmin, we can only change a key that we own */
1091        if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) {
1092                key->perm = perm;
1093                notify_key(key, NOTIFY_KEY_SETATTR, 0);
1094                ret = 0;
1095        }
1096
1097        up_write(&key->sem);
1098        key_put(key);
1099error:
1100        return ret;
1101}
1102
1103/*
1104 * Get the destination keyring for instantiation and check that the caller has
1105 * Write permission on it.
1106 */
1107static long get_instantiation_keyring(key_serial_t ringid,
1108                                      struct request_key_auth *rka,
1109                                      struct key **_dest_keyring)
1110{
1111        key_ref_t dkref;
1112
1113        *_dest_keyring = NULL;
1114
1115        /* just return a NULL pointer if we weren't asked to make a link */
1116        if (ringid == 0)
1117                return 0;
1118
1119        /* if a specific keyring is nominated by ID, then use that */
1120        if (ringid > 0) {
1121                dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
1122                if (IS_ERR(dkref))
1123                        return PTR_ERR(dkref);
1124                *_dest_keyring = key_ref_to_ptr(dkref);
1125                return 0;
1126        }
1127
1128        if (ringid == KEY_SPEC_REQKEY_AUTH_KEY)
1129                return -EINVAL;
1130
1131        /* otherwise specify the destination keyring recorded in the
1132         * authorisation key (any KEY_SPEC_*_KEYRING) */
1133        if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) {
1134                *_dest_keyring = key_get(rka->dest_keyring);
1135                return 0;
1136        }
1137
1138        return -ENOKEY;
1139}
1140
1141/*
1142 * Change the request_key authorisation key on the current process.
1143 */
1144static int keyctl_change_reqkey_auth(struct key *key)
1145{
1146        struct cred *new;
1147
1148        new = prepare_creds();
1149        if (!new)
1150                return -ENOMEM;
1151
1152        key_put(new->request_key_auth);
1153        new->request_key_auth = key_get(key);
1154
1155        return commit_creds(new);
1156}
1157
1158/*
1159 * Instantiate a key with the specified payload and link the key into the
1160 * destination keyring if one is given.
1161 *
1162 * The caller must have the appropriate instantiation permit set for this to
1163 * work (see keyctl_assume_authority).  No other permissions are required.
1164 *
1165 * If successful, 0 will be returned.
1166 */
1167static long keyctl_instantiate_key_common(key_serial_t id,
1168                                   struct iov_iter *from,
1169                                   key_serial_t ringid)
1170{
1171        const struct cred *cred = current_cred();
1172        struct request_key_auth *rka;
1173        struct key *instkey, *dest_keyring;
1174        size_t plen = from ? iov_iter_count(from) : 0;
1175        void *payload;
1176        long ret;
1177
1178        kenter("%d,,%zu,%d", id, plen, ringid);
1179
1180        if (!plen)
1181                from = NULL;
1182
1183        ret = -EINVAL;
1184        if (plen > 1024 * 1024 - 1)
1185                goto error;
1186
1187        /* the appropriate instantiation authorisation key must have been
1188         * assumed before calling this */
1189        ret = -EPERM;
1190        instkey = cred->request_key_auth;
1191        if (!instkey)
1192                goto error;
1193
1194        rka = instkey->payload.data[0];
1195        if (rka->target_key->serial != id)
1196                goto error;
1197
1198        /* pull the payload in if one was supplied */
1199        payload = NULL;
1200
1201        if (from) {
1202                ret = -ENOMEM;
1203                payload = kvmalloc(plen, GFP_KERNEL);
1204                if (!payload)
1205                        goto error;
1206
1207                ret = -EFAULT;
1208                if (!copy_from_iter_full(payload, plen, from))
1209                        goto error2;
1210        }
1211
1212        /* find the destination keyring amongst those belonging to the
1213         * requesting task */
1214        ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1215        if (ret < 0)
1216                goto error2;
1217
1218        /* instantiate the key and link it into a keyring */
1219        ret = key_instantiate_and_link(rka->target_key, payload, plen,
1220                                       dest_keyring, instkey);
1221
1222        key_put(dest_keyring);
1223
1224        /* discard the assumed authority if it's just been disabled by
1225         * instantiation of the key */
1226        if (ret == 0)
1227                keyctl_change_reqkey_auth(NULL);
1228
1229error2:
1230        kvfree_sensitive(payload, plen);
1231error:
1232        return ret;
1233}
1234
1235/*
1236 * Instantiate a key with the specified payload and link the key into the
1237 * destination keyring if one is given.
1238 *
1239 * The caller must have the appropriate instantiation permit set for this to
1240 * work (see keyctl_assume_authority).  No other permissions are required.
1241 *
1242 * If successful, 0 will be returned.
1243 */
1244long keyctl_instantiate_key(key_serial_t id,
1245                            const void __user *_payload,
1246                            size_t plen,
1247                            key_serial_t ringid)
1248{
1249        if (_payload && plen) {
1250                struct iovec iov;
1251                struct iov_iter from;
1252                int ret;
1253
1254                ret = import_single_range(WRITE, (void __user *)_payload, plen,
1255                                          &iov, &from);
1256                if (unlikely(ret))
1257                        return ret;
1258
1259                return keyctl_instantiate_key_common(id, &from, ringid);
1260        }
1261
1262        return keyctl_instantiate_key_common(id, NULL, ringid);
1263}
1264
1265/*
1266 * Instantiate a key with the specified multipart payload and link the key into
1267 * the destination keyring if one is given.
1268 *
1269 * The caller must have the appropriate instantiation permit set for this to
1270 * work (see keyctl_assume_authority).  No other permissions are required.
1271 *
1272 * If successful, 0 will be returned.
1273 */
1274long keyctl_instantiate_key_iov(key_serial_t id,
1275                                const struct iovec __user *_payload_iov,
1276                                unsigned ioc,
1277                                key_serial_t ringid)
1278{
1279        struct iovec iovstack[UIO_FASTIOV], *iov = iovstack;
1280        struct iov_iter from;
1281        long ret;
1282
1283        if (!_payload_iov)
1284                ioc = 0;
1285
1286        ret = import_iovec(WRITE, _payload_iov, ioc,
1287                                    ARRAY_SIZE(iovstack), &iov, &from);
1288        if (ret < 0)
1289                return ret;
1290        ret = keyctl_instantiate_key_common(id, &from, ringid);
1291        kfree(iov);
1292        return ret;
1293}
1294
1295/*
1296 * Negatively instantiate the key with the given timeout (in seconds) and link
1297 * the key into the destination keyring if one is given.
1298 *
1299 * The caller must have the appropriate instantiation permit set for this to
1300 * work (see keyctl_assume_authority).  No other permissions are required.
1301 *
1302 * The key and any links to the key will be automatically garbage collected
1303 * after the timeout expires.
1304 *
1305 * Negative keys are used to rate limit repeated request_key() calls by causing
1306 * them to return -ENOKEY until the negative key expires.
1307 *
1308 * If successful, 0 will be returned.
1309 */
1310long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
1311{
1312        return keyctl_reject_key(id, timeout, ENOKEY, ringid);
1313}
1314
1315/*
1316 * Negatively instantiate the key with the given timeout (in seconds) and error
1317 * code and link the key into the destination keyring if one is given.
1318 *
1319 * The caller must have the appropriate instantiation permit set for this to
1320 * work (see keyctl_assume_authority).  No other permissions are required.
1321 *
1322 * The key and any links to the key will be automatically garbage collected
1323 * after the timeout expires.
1324 *
1325 * Negative keys are used to rate limit repeated request_key() calls by causing
1326 * them to return the specified error code until the negative key expires.
1327 *
1328 * If successful, 0 will be returned.
1329 */
1330long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error,
1331                       key_serial_t ringid)
1332{
1333        const struct cred *cred = current_cred();
1334        struct request_key_auth *rka;
1335        struct key *instkey, *dest_keyring;
1336        long ret;
1337
1338        kenter("%d,%u,%u,%d", id, timeout, error, ringid);
1339
1340        /* must be a valid error code and mustn't be a kernel special */
1341        if (error <= 0 ||
1342            error >= MAX_ERRNO ||
1343            error == ERESTARTSYS ||
1344            error == ERESTARTNOINTR ||
1345            error == ERESTARTNOHAND ||
1346            error == ERESTART_RESTARTBLOCK)
1347                return -EINVAL;
1348
1349        /* the appropriate instantiation authorisation key must have been
1350         * assumed before calling this */
1351        ret = -EPERM;
1352        instkey = cred->request_key_auth;
1353        if (!instkey)
1354                goto error;
1355
1356        rka = instkey->payload.data[0];
1357        if (rka->target_key->serial != id)
1358                goto error;
1359
1360        /* find the destination keyring if present (which must also be
1361         * writable) */
1362        ret = get_instantiation_keyring(ringid, rka, &dest_keyring);
1363        if (ret < 0)
1364                goto error;
1365
1366        /* instantiate the key and link it into a keyring */
1367        ret = key_reject_and_link(rka->target_key, timeout, error,
1368                                  dest_keyring, instkey);
1369
1370        key_put(dest_keyring);
1371
1372        /* discard the assumed authority if it's just been disabled by
1373         * instantiation of the key */
1374        if (ret == 0)
1375                keyctl_change_reqkey_auth(NULL);
1376
1377error:
1378        return ret;
1379}
1380
1381/*
1382 * Read or set the default keyring in which request_key() will cache keys and
1383 * return the old setting.
1384 *
1385 * If a thread or process keyring is specified then it will be created if it
1386 * doesn't yet exist.  The old setting will be returned if successful.
1387 */
1388long keyctl_set_reqkey_keyring(int reqkey_defl)
1389{
1390        struct cred *new;
1391        int ret, old_setting;
1392
1393        old_setting = current_cred_xxx(jit_keyring);
1394
1395        if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE)
1396                return old_setting;
1397
1398        new = prepare_creds();
1399        if (!new)
1400                return -ENOMEM;
1401
1402        switch (reqkey_defl) {
1403        case KEY_REQKEY_DEFL_THREAD_KEYRING:
1404                ret = install_thread_keyring_to_cred(new);
1405                if (ret < 0)
1406                        goto error;
1407                goto set;
1408
1409        case KEY_REQKEY_DEFL_PROCESS_KEYRING:
1410                ret = install_process_keyring_to_cred(new);
1411                if (ret < 0)
1412                        goto error;
1413                goto set;
1414
1415        case KEY_REQKEY_DEFL_DEFAULT:
1416        case KEY_REQKEY_DEFL_SESSION_KEYRING:
1417        case KEY_REQKEY_DEFL_USER_KEYRING:
1418        case KEY_REQKEY_DEFL_USER_SESSION_KEYRING:
1419        case KEY_REQKEY_DEFL_REQUESTOR_KEYRING:
1420                goto set;
1421
1422        case KEY_REQKEY_DEFL_NO_CHANGE:
1423        case KEY_REQKEY_DEFL_GROUP_KEYRING:
1424        default:
1425                ret = -EINVAL;
1426                goto error;
1427        }
1428
1429set:
1430        new->jit_keyring = reqkey_defl;
1431        commit_creds(new);
1432        return old_setting;
1433error:
1434        abort_creds(new);
1435        return ret;
1436}
1437
1438/*
1439 * Set or clear the timeout on a key.
1440 *
1441 * Either the key must grant the caller Setattr permission or else the caller
1442 * must hold an instantiation authorisation token for the key.
1443 *
1444 * The timeout is either 0 to clear the timeout, or a number of seconds from
1445 * the current time.  The key and any links to the key will be automatically
1446 * garbage collected after the timeout expires.
1447 *
1448 * Keys with KEY_FLAG_KEEP set should not be timed out.
1449 *
1450 * If successful, 0 is returned.
1451 */
1452long keyctl_set_timeout(key_serial_t id, unsigned timeout)
1453{
1454        struct key *key, *instkey;
1455        key_ref_t key_ref;
1456        long ret;
1457
1458        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL,
1459                                  KEY_NEED_SETATTR);
1460        if (IS_ERR(key_ref)) {
1461                /* setting the timeout on a key under construction is permitted
1462                 * if we have the authorisation token handy */
1463                if (PTR_ERR(key_ref) == -EACCES) {
1464                        instkey = key_get_instantiation_authkey(id);
1465                        if (!IS_ERR(instkey)) {
1466                                key_put(instkey);
1467                                key_ref = lookup_user_key(id,
1468                                                          KEY_LOOKUP_PARTIAL,
1469                                                          KEY_AUTHTOKEN_OVERRIDE);
1470                                if (!IS_ERR(key_ref))
1471                                        goto okay;
1472                        }
1473                }
1474
1475                ret = PTR_ERR(key_ref);
1476                goto error;
1477        }
1478
1479okay:
1480        key = key_ref_to_ptr(key_ref);
1481        ret = 0;
1482        if (test_bit(KEY_FLAG_KEEP, &key->flags)) {
1483                ret = -EPERM;
1484        } else {
1485                key_set_timeout(key, timeout);
1486                notify_key(key, NOTIFY_KEY_SETATTR, 0);
1487        }
1488        key_put(key);
1489
1490error:
1491        return ret;
1492}
1493
1494/*
1495 * Assume (or clear) the authority to instantiate the specified key.
1496 *
1497 * This sets the authoritative token currently in force for key instantiation.
1498 * This must be done for a key to be instantiated.  It has the effect of making
1499 * available all the keys from the caller of the request_key() that created a
1500 * key to request_key() calls made by the caller of this function.
1501 *
1502 * The caller must have the instantiation key in their process keyrings with a
1503 * Search permission grant available to the caller.
1504 *
1505 * If the ID given is 0, then the setting will be cleared and 0 returned.
1506 *
1507 * If the ID given has a matching an authorisation key, then that key will be
1508 * set and its ID will be returned.  The authorisation key can be read to get
1509 * the callout information passed to request_key().
1510 */
1511long keyctl_assume_authority(key_serial_t id)
1512{
1513        struct key *authkey;
1514        long ret;
1515
1516        /* special key IDs aren't permitted */
1517        ret = -EINVAL;
1518        if (id < 0)
1519                goto error;
1520
1521        /* we divest ourselves of authority if given an ID of 0 */
1522        if (id == 0) {
1523                ret = keyctl_change_reqkey_auth(NULL);
1524                goto error;
1525        }
1526
1527        /* attempt to assume the authority temporarily granted to us whilst we
1528         * instantiate the specified key
1529         * - the authorisation key must be in the current task's keyrings
1530         *   somewhere
1531         */
1532        authkey = key_get_instantiation_authkey(id);
1533        if (IS_ERR(authkey)) {
1534                ret = PTR_ERR(authkey);
1535                goto error;
1536        }
1537
1538        ret = keyctl_change_reqkey_auth(authkey);
1539        if (ret == 0)
1540                ret = authkey->serial;
1541        key_put(authkey);
1542error:
1543        return ret;
1544}
1545
1546/*
1547 * Get a key's the LSM security label.
1548 *
1549 * The key must grant the caller View permission for this to work.
1550 *
1551 * If there's a buffer, then up to buflen bytes of data will be placed into it.
1552 *
1553 * If successful, the amount of information available will be returned,
1554 * irrespective of how much was copied (including the terminal NUL).
1555 */
1556long keyctl_get_security(key_serial_t keyid,
1557                         char __user *buffer,
1558                         size_t buflen)
1559{
1560        struct key *key, *instkey;
1561        key_ref_t key_ref;
1562        char *context;
1563        long ret;
1564
1565        key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_NEED_VIEW);
1566        if (IS_ERR(key_ref)) {
1567                if (PTR_ERR(key_ref) != -EACCES)
1568                        return PTR_ERR(key_ref);
1569
1570                /* viewing a key under construction is also permitted if we
1571                 * have the authorisation token handy */
1572                instkey = key_get_instantiation_authkey(keyid);
1573                if (IS_ERR(instkey))
1574                        return PTR_ERR(instkey);
1575                key_put(instkey);
1576
1577                key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL,
1578                                          KEY_AUTHTOKEN_OVERRIDE);
1579                if (IS_ERR(key_ref))
1580                        return PTR_ERR(key_ref);
1581        }
1582
1583        key = key_ref_to_ptr(key_ref);
1584        ret = security_key_getsecurity(key, &context);
1585        if (ret == 0) {
1586                /* if no information was returned, give userspace an empty
1587                 * string */
1588                ret = 1;
1589                if (buffer && buflen > 0 &&
1590                    copy_to_user(buffer, "", 1) != 0)
1591                        ret = -EFAULT;
1592        } else if (ret > 0) {
1593                /* return as much data as there's room for */
1594                if (buffer && buflen > 0) {
1595                        if (buflen > ret)
1596                                buflen = ret;
1597
1598                        if (copy_to_user(buffer, context, buflen) != 0)
1599                                ret = -EFAULT;
1600                }
1601
1602                kfree(context);
1603        }
1604
1605        key_ref_put(key_ref);
1606        return ret;
1607}
1608
1609/*
1610 * Attempt to install the calling process's session keyring on the process's
1611 * parent process.
1612 *
1613 * The keyring must exist and must grant the caller LINK permission, and the
1614 * parent process must be single-threaded and must have the same effective
1615 * ownership as this process and mustn't be SUID/SGID.
1616 *
1617 * The keyring will be emplaced on the parent when it next resumes userspace.
1618 *
1619 * If successful, 0 will be returned.
1620 */
1621long keyctl_session_to_parent(void)
1622{
1623        struct task_struct *me, *parent;
1624        const struct cred *mycred, *pcred;
1625        struct callback_head *newwork, *oldwork;
1626        key_ref_t keyring_r;
1627        struct cred *cred;
1628        int ret;
1629
1630        keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_NEED_LINK);
1631        if (IS_ERR(keyring_r))
1632                return PTR_ERR(keyring_r);
1633
1634        ret = -ENOMEM;
1635
1636        /* our parent is going to need a new cred struct, a new tgcred struct
1637         * and new security data, so we allocate them here to prevent ENOMEM in
1638         * our parent */
1639        cred = cred_alloc_blank();
1640        if (!cred)
1641                goto error_keyring;
1642        newwork = &cred->rcu;
1643
1644        cred->session_keyring = key_ref_to_ptr(keyring_r);
1645        keyring_r = NULL;
1646        init_task_work(newwork, key_change_session_keyring);
1647
1648        me = current;
1649        rcu_read_lock();
1650        write_lock_irq(&tasklist_lock);
1651
1652        ret = -EPERM;
1653        oldwork = NULL;
1654        parent = rcu_dereference_protected(me->real_parent,
1655                                           lockdep_is_held(&tasklist_lock));
1656
1657        /* the parent mustn't be init and mustn't be a kernel thread */
1658        if (parent->pid <= 1 || !parent->mm)
1659                goto unlock;
1660
1661        /* the parent must be single threaded */
1662        if (!thread_group_empty(parent))
1663                goto unlock;
1664
1665        /* the parent and the child must have different session keyrings or
1666         * there's no point */
1667        mycred = current_cred();
1668        pcred = __task_cred(parent);
1669        if (mycred == pcred ||
1670            mycred->session_keyring == pcred->session_keyring) {
1671                ret = 0;
1672                goto unlock;
1673        }
1674
1675        /* the parent must have the same effective ownership and mustn't be
1676         * SUID/SGID */
1677        if (!uid_eq(pcred->uid,  mycred->euid) ||
1678            !uid_eq(pcred->euid, mycred->euid) ||
1679            !uid_eq(pcred->suid, mycred->euid) ||
1680            !gid_eq(pcred->gid,  mycred->egid) ||
1681            !gid_eq(pcred->egid, mycred->egid) ||
1682            !gid_eq(pcred->sgid, mycred->egid))
1683                goto unlock;
1684
1685        /* the keyrings must have the same UID */
1686        if ((pcred->session_keyring &&
1687             !uid_eq(pcred->session_keyring->uid, mycred->euid)) ||
1688            !uid_eq(mycred->session_keyring->uid, mycred->euid))
1689                goto unlock;
1690
1691        /* cancel an already pending keyring replacement */
1692        oldwork = task_work_cancel(parent, key_change_session_keyring);
1693
1694        /* the replacement session keyring is applied just prior to userspace
1695         * restarting */
1696        ret = task_work_add(parent, newwork, TWA_RESUME);
1697        if (!ret)
1698                newwork = NULL;
1699unlock:
1700        write_unlock_irq(&tasklist_lock);
1701        rcu_read_unlock();
1702        if (oldwork)
1703                put_cred(container_of(oldwork, struct cred, rcu));
1704        if (newwork)
1705                put_cred(cred);
1706        return ret;
1707
1708error_keyring:
1709        key_ref_put(keyring_r);
1710        return ret;
1711}
1712
1713/*
1714 * Apply a restriction to a given keyring.
1715 *
1716 * The caller must have Setattr permission to change keyring restrictions.
1717 *
1718 * The requested type name may be a NULL pointer to reject all attempts
1719 * to link to the keyring.  In this case, _restriction must also be NULL.
1720 * Otherwise, both _type and _restriction must be non-NULL.
1721 *
1722 * Returns 0 if successful.
1723 */
1724long keyctl_restrict_keyring(key_serial_t id, const char __user *_type,
1725                             const char __user *_restriction)
1726{
1727        key_ref_t key_ref;
1728        char type[32];
1729        char *restriction = NULL;
1730        long ret;
1731
1732        key_ref = lookup_user_key(id, 0, KEY_NEED_SETATTR);
1733        if (IS_ERR(key_ref))
1734                return PTR_ERR(key_ref);
1735
1736        ret = -EINVAL;
1737        if (_type) {
1738                if (!_restriction)
1739                        goto error;
1740
1741                ret = key_get_type_from_user(type, _type, sizeof(type));
1742                if (ret < 0)
1743                        goto error;
1744
1745                restriction = strndup_user(_restriction, PAGE_SIZE);
1746                if (IS_ERR(restriction)) {
1747                        ret = PTR_ERR(restriction);
1748                        goto error;
1749                }
1750        } else {
1751                if (_restriction)
1752                        goto error;
1753        }
1754
1755        ret = keyring_restrict(key_ref, _type ? type : NULL, restriction);
1756        kfree(restriction);
1757error:
1758        key_ref_put(key_ref);
1759        return ret;
1760}
1761
1762#ifdef CONFIG_KEY_NOTIFICATIONS
1763/*
1764 * Watch for changes to a key.
1765 *
1766 * The caller must have View permission to watch a key or keyring.
1767 */
1768long keyctl_watch_key(key_serial_t id, int watch_queue_fd, int watch_id)
1769{
1770        struct watch_queue *wqueue;
1771        struct watch_list *wlist = NULL;
1772        struct watch *watch = NULL;
1773        struct key *key;
1774        key_ref_t key_ref;
1775        long ret;
1776
1777        if (watch_id < -1 || watch_id > 0xff)
1778                return -EINVAL;
1779
1780        key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_NEED_VIEW);
1781        if (IS_ERR(key_ref))
1782                return PTR_ERR(key_ref);
1783        key = key_ref_to_ptr(key_ref);
1784
1785        wqueue = get_watch_queue(watch_queue_fd);
1786        if (IS_ERR(wqueue)) {
1787                ret = PTR_ERR(wqueue);
1788                goto err_key;
1789        }
1790
1791        if (watch_id >= 0) {
1792                ret = -ENOMEM;
1793                if (!key->watchers) {
1794                        wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
1795                        if (!wlist)
1796                                goto err_wqueue;
1797                        init_watch_list(wlist, NULL);
1798                }
1799
1800                watch = kzalloc(sizeof(*watch), GFP_KERNEL);
1801                if (!watch)
1802                        goto err_wlist;
1803
1804                init_watch(watch, wqueue);
1805                watch->id       = key->serial;
1806                watch->info_id  = (u32)watch_id << WATCH_INFO_ID__SHIFT;
1807
1808                ret = security_watch_key(key);
1809                if (ret < 0)
1810                        goto err_watch;
1811
1812                down_write(&key->sem);
1813                if (!key->watchers) {
1814                        key->watchers = wlist;
1815                        wlist = NULL;
1816                }
1817
1818                ret = add_watch_to_object(watch, key->watchers);
1819                up_write(&key->sem);
1820
1821                if (ret == 0)
1822                        watch = NULL;
1823        } else {
1824                ret = -EBADSLT;
1825                if (key->watchers) {
1826                        down_write(&key->sem);
1827                        ret = remove_watch_from_object(key->watchers,
1828                                                       wqueue, key_serial(key),
1829                                                       false);
1830                        up_write(&key->sem);
1831                }
1832        }
1833
1834err_watch:
1835        kfree(watch);
1836err_wlist:
1837        kfree(wlist);
1838err_wqueue:
1839        put_watch_queue(wqueue);
1840err_key:
1841        key_put(key);
1842        return ret;
1843}
1844#endif /* CONFIG_KEY_NOTIFICATIONS */
1845
1846/*
1847 * Get keyrings subsystem capabilities.
1848 */
1849long keyctl_capabilities(unsigned char __user *_buffer, size_t buflen)
1850{
1851        size_t size = buflen;
1852
1853        if (size > 0) {
1854                if (size > sizeof(keyrings_capabilities))
1855                        size = sizeof(keyrings_capabilities);
1856                if (copy_to_user(_buffer, keyrings_capabilities, size) != 0)
1857                        return -EFAULT;
1858                if (size < buflen &&
1859                    clear_user(_buffer + size, buflen - size) != 0)
1860                        return -EFAULT;
1861        }
1862
1863        return sizeof(keyrings_capabilities);
1864}
1865
1866/*
1867 * The key control system call
1868 */
1869SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3,
1870                unsigned long, arg4, unsigned long, arg5)
1871{
1872        switch (option) {
1873        case KEYCTL_GET_KEYRING_ID:
1874                return keyctl_get_keyring_ID((key_serial_t) arg2,
1875                                             (int) arg3);
1876
1877        case KEYCTL_JOIN_SESSION_KEYRING:
1878                return keyctl_join_session_keyring((const char __user *) arg2);
1879
1880        case KEYCTL_UPDATE:
1881                return keyctl_update_key((key_serial_t) arg2,
1882                                         (const void __user *) arg3,
1883                                         (size_t) arg4);
1884
1885        case KEYCTL_REVOKE:
1886                return keyctl_revoke_key((key_serial_t) arg2);
1887
1888        case KEYCTL_DESCRIBE:
1889                return keyctl_describe_key((key_serial_t) arg2,
1890                                           (char __user *) arg3,
1891                                           (unsigned) arg4);
1892
1893        case KEYCTL_CLEAR:
1894                return keyctl_keyring_clear((key_serial_t) arg2);
1895
1896        case KEYCTL_LINK:
1897                return keyctl_keyring_link((key_serial_t) arg2,
1898                                           (key_serial_t) arg3);
1899
1900        case KEYCTL_UNLINK:
1901                return keyctl_keyring_unlink((key_serial_t) arg2,
1902                                             (key_serial_t) arg3);
1903
1904        case KEYCTL_SEARCH:
1905                return keyctl_keyring_search((key_serial_t) arg2,
1906                                             (const char __user *) arg3,
1907                                             (const char __user *) arg4,
1908                                             (key_serial_t) arg5);
1909
1910        case KEYCTL_READ:
1911                return keyctl_read_key((key_serial_t) arg2,
1912                                       (char __user *) arg3,
1913                                       (size_t) arg4);
1914
1915        case KEYCTL_CHOWN:
1916                return keyctl_chown_key((key_serial_t) arg2,
1917                                        (uid_t) arg3,
1918                                        (gid_t) arg4);
1919
1920        case KEYCTL_SETPERM:
1921                return keyctl_setperm_key((key_serial_t) arg2,
1922                                          (key_perm_t) arg3);
1923
1924        case KEYCTL_INSTANTIATE:
1925                return keyctl_instantiate_key((key_serial_t) arg2,
1926                                              (const void __user *) arg3,
1927                                              (size_t) arg4,
1928                                              (key_serial_t) arg5);
1929
1930        case KEYCTL_NEGATE:
1931                return keyctl_negate_key((key_serial_t) arg2,
1932                                         (unsigned) arg3,
1933                                         (key_serial_t) arg4);
1934
1935        case KEYCTL_SET_REQKEY_KEYRING:
1936                return keyctl_set_reqkey_keyring(arg2);
1937
1938        case KEYCTL_SET_TIMEOUT:
1939                return keyctl_set_timeout((key_serial_t) arg2,
1940                                          (unsigned) arg3);
1941
1942        case KEYCTL_ASSUME_AUTHORITY:
1943                return keyctl_assume_authority((key_serial_t) arg2);
1944
1945        case KEYCTL_GET_SECURITY:
1946                return keyctl_get_security((key_serial_t) arg2,
1947                                           (char __user *) arg3,
1948                                           (size_t) arg4);
1949
1950        case KEYCTL_SESSION_TO_PARENT:
1951                return keyctl_session_to_parent();
1952
1953        case KEYCTL_REJECT:
1954                return keyctl_reject_key((key_serial_t) arg2,
1955                                         (unsigned) arg3,
1956                                         (unsigned) arg4,
1957                                         (key_serial_t) arg5);
1958
1959        case KEYCTL_INSTANTIATE_IOV:
1960                return keyctl_instantiate_key_iov(
1961                        (key_serial_t) arg2,
1962                        (const struct iovec __user *) arg3,
1963                        (unsigned) arg4,
1964                        (key_serial_t) arg5);
1965
1966        case KEYCTL_INVALIDATE:
1967                return keyctl_invalidate_key((key_serial_t) arg2);
1968
1969        case KEYCTL_GET_PERSISTENT:
1970                return keyctl_get_persistent((uid_t)arg2, (key_serial_t)arg3);
1971
1972        case KEYCTL_DH_COMPUTE:
1973                return keyctl_dh_compute((struct keyctl_dh_params __user *) arg2,
1974                                         (char __user *) arg3, (size_t) arg4,
1975                                         (struct keyctl_kdf_params __user *) arg5);
1976
1977        case KEYCTL_RESTRICT_KEYRING:
1978                return keyctl_restrict_keyring((key_serial_t) arg2,
1979                                               (const char __user *) arg3,
1980                                               (const char __user *) arg4);
1981
1982        case KEYCTL_PKEY_QUERY:
1983                if (arg3 != 0)
1984                        return -EINVAL;
1985                return keyctl_pkey_query((key_serial_t)arg2,
1986                                         (const char __user *)arg4,
1987                                         (struct keyctl_pkey_query __user *)arg5);
1988
1989        case KEYCTL_PKEY_ENCRYPT:
1990        case KEYCTL_PKEY_DECRYPT:
1991        case KEYCTL_PKEY_SIGN:
1992                return keyctl_pkey_e_d_s(
1993                        option,
1994                        (const struct keyctl_pkey_params __user *)arg2,
1995                        (const char __user *)arg3,
1996                        (const void __user *)arg4,
1997                        (void __user *)arg5);
1998
1999        case KEYCTL_PKEY_VERIFY:
2000                return keyctl_pkey_verify(
2001                        (const struct keyctl_pkey_params __user *)arg2,
2002                        (const char __user *)arg3,
2003                        (const void __user *)arg4,
2004                        (const void __user *)arg5);
2005
2006        case KEYCTL_MOVE:
2007                return keyctl_keyring_move((key_serial_t)arg2,
2008                                           (key_serial_t)arg3,
2009                                           (key_serial_t)arg4,
2010                                           (unsigned int)arg5);
2011
2012        case KEYCTL_CAPABILITIES:
2013                return keyctl_capabilities((unsigned char __user *)arg2, (size_t)arg3);
2014
2015        case KEYCTL_WATCH_KEY:
2016                return keyctl_watch_key((key_serial_t)arg2, (int)arg3, (int)arg4);
2017
2018        default:
2019                return -EOPNOTSUPP;
2020        }
2021}
2022
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