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