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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 <asm/uaccess.h> |
26 | #include "internal.h" |
27 | |
28 | static int key_get_type_from_user(char *type, |
29 | const char __user *_type, |
30 | unsigned len) |
31 | { |
32 | int ret; |
33 | |
34 | ret = strncpy_from_user(type, _type, len); |
35 | if (ret < 0) |
36 | return ret; |
37 | if (ret == 0 || ret >= len) |
38 | return -EINVAL; |
39 | if (type[0] == '.') |
40 | return -EPERM; |
41 | type[len - 1] = '\0'; |
42 | return 0; |
43 | } |
44 | |
45 | /* |
46 | * Extract the description of a new key from userspace and either add it as a |
47 | * new key to the specified keyring or update a matching key in that keyring. |
48 | * |
49 | * The keyring must be writable so that we can attach the key to it. |
50 | * |
51 | * If successful, the new key's serial number is returned, otherwise an error |
52 | * code is returned. |
53 | */ |
54 | SYSCALL_DEFINE5(add_key, const char __user *, _type, |
55 | const char __user *, _description, |
56 | const void __user *, _payload, |
57 | size_t, plen, |
58 | key_serial_t, ringid) |
59 | { |
60 | key_ref_t keyring_ref, key_ref; |
61 | char type[32], *description; |
62 | void *payload; |
63 | long ret; |
64 | bool vm; |
65 | |
66 | ret = -EINVAL; |
67 | if (plen > 1024 * 1024 - 1) |
68 | goto error; |
69 | |
70 | /* draw all the data into kernel space */ |
71 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
72 | if (ret < 0) |
73 | goto error; |
74 | |
75 | description = strndup_user(_description, PAGE_SIZE); |
76 | if (IS_ERR(description)) { |
77 | ret = PTR_ERR(description); |
78 | goto error; |
79 | } |
80 | |
81 | /* pull the payload in if one was supplied */ |
82 | payload = NULL; |
83 | |
84 | vm = false; |
85 | if (_payload) { |
86 | ret = -ENOMEM; |
87 | payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN); |
88 | if (!payload) { |
89 | if (plen <= PAGE_SIZE) |
90 | goto error2; |
91 | vm = true; |
92 | payload = vmalloc(plen); |
93 | if (!payload) |
94 | goto error2; |
95 | } |
96 | |
97 | ret = -EFAULT; |
98 | if (copy_from_user(payload, _payload, plen) != 0) |
99 | goto error3; |
100 | } |
101 | |
102 | /* find the target keyring (which must be writable) */ |
103 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
104 | if (IS_ERR(keyring_ref)) { |
105 | ret = PTR_ERR(keyring_ref); |
106 | goto error3; |
107 | } |
108 | |
109 | /* create or update the requested key and add it to the target |
110 | * keyring */ |
111 | key_ref = key_create_or_update(keyring_ref, type, description, |
112 | payload, plen, KEY_PERM_UNDEF, |
113 | KEY_ALLOC_IN_QUOTA); |
114 | if (!IS_ERR(key_ref)) { |
115 | ret = key_ref_to_ptr(key_ref)->serial; |
116 | key_ref_put(key_ref); |
117 | } |
118 | else { |
119 | ret = PTR_ERR(key_ref); |
120 | } |
121 | |
122 | key_ref_put(keyring_ref); |
123 | error3: |
124 | if (!vm) |
125 | kfree(payload); |
126 | else |
127 | vfree(payload); |
128 | error2: |
129 | kfree(description); |
130 | error: |
131 | return ret; |
132 | } |
133 | |
134 | /* |
135 | * Search the process keyrings and keyring trees linked from those for a |
136 | * matching key. Keyrings must have appropriate Search permission to be |
137 | * searched. |
138 | * |
139 | * If a key is found, it will be attached to the destination keyring if there's |
140 | * one specified and the serial number of the key will be returned. |
141 | * |
142 | * If no key is found, /sbin/request-key will be invoked if _callout_info is |
143 | * non-NULL in an attempt to create a key. The _callout_info string will be |
144 | * passed to /sbin/request-key to aid with completing the request. If the |
145 | * _callout_info string is "" then it will be changed to "-". |
146 | */ |
147 | SYSCALL_DEFINE4(request_key, const char __user *, _type, |
148 | const char __user *, _description, |
149 | const char __user *, _callout_info, |
150 | key_serial_t, destringid) |
151 | { |
152 | struct key_type *ktype; |
153 | struct key *key; |
154 | key_ref_t dest_ref; |
155 | size_t callout_len; |
156 | char type[32], *description, *callout_info; |
157 | long ret; |
158 | |
159 | /* pull the type into kernel space */ |
160 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
161 | if (ret < 0) |
162 | goto error; |
163 | |
164 | /* pull the description into kernel space */ |
165 | description = strndup_user(_description, PAGE_SIZE); |
166 | if (IS_ERR(description)) { |
167 | ret = PTR_ERR(description); |
168 | goto error; |
169 | } |
170 | |
171 | /* pull the callout info into kernel space */ |
172 | callout_info = NULL; |
173 | callout_len = 0; |
174 | if (_callout_info) { |
175 | callout_info = strndup_user(_callout_info, PAGE_SIZE); |
176 | if (IS_ERR(callout_info)) { |
177 | ret = PTR_ERR(callout_info); |
178 | goto error2; |
179 | } |
180 | callout_len = strlen(callout_info); |
181 | } |
182 | |
183 | /* get the destination keyring if specified */ |
184 | dest_ref = NULL; |
185 | if (destringid) { |
186 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, |
187 | KEY_WRITE); |
188 | if (IS_ERR(dest_ref)) { |
189 | ret = PTR_ERR(dest_ref); |
190 | goto error3; |
191 | } |
192 | } |
193 | |
194 | /* find the key type */ |
195 | ktype = key_type_lookup(type); |
196 | if (IS_ERR(ktype)) { |
197 | ret = PTR_ERR(ktype); |
198 | goto error4; |
199 | } |
200 | |
201 | /* do the search */ |
202 | key = request_key_and_link(ktype, description, callout_info, |
203 | callout_len, NULL, key_ref_to_ptr(dest_ref), |
204 | KEY_ALLOC_IN_QUOTA); |
205 | if (IS_ERR(key)) { |
206 | ret = PTR_ERR(key); |
207 | goto error5; |
208 | } |
209 | |
210 | /* wait for the key to finish being constructed */ |
211 | ret = wait_for_key_construction(key, 1); |
212 | if (ret < 0) |
213 | goto error6; |
214 | |
215 | ret = key->serial; |
216 | |
217 | error6: |
218 | key_put(key); |
219 | error5: |
220 | key_type_put(ktype); |
221 | error4: |
222 | key_ref_put(dest_ref); |
223 | error3: |
224 | kfree(callout_info); |
225 | error2: |
226 | kfree(description); |
227 | error: |
228 | return ret; |
229 | } |
230 | |
231 | /* |
232 | * Get the ID of the specified process keyring. |
233 | * |
234 | * The requested keyring must have search permission to be found. |
235 | * |
236 | * If successful, the ID of the requested keyring will be returned. |
237 | */ |
238 | long keyctl_get_keyring_ID(key_serial_t id, int create) |
239 | { |
240 | key_ref_t key_ref; |
241 | unsigned long lflags; |
242 | long ret; |
243 | |
244 | lflags = create ? KEY_LOOKUP_CREATE : 0; |
245 | key_ref = lookup_user_key(id, lflags, KEY_SEARCH); |
246 | if (IS_ERR(key_ref)) { |
247 | ret = PTR_ERR(key_ref); |
248 | goto error; |
249 | } |
250 | |
251 | ret = key_ref_to_ptr(key_ref)->serial; |
252 | key_ref_put(key_ref); |
253 | error: |
254 | return ret; |
255 | } |
256 | |
257 | /* |
258 | * Join a (named) session keyring. |
259 | * |
260 | * Create and join an anonymous session keyring or join a named session |
261 | * keyring, creating it if necessary. A named session keyring must have Search |
262 | * permission for it to be joined. Session keyrings without this permit will |
263 | * be skipped over. |
264 | * |
265 | * If successful, the ID of the joined session keyring will be returned. |
266 | */ |
267 | long keyctl_join_session_keyring(const char __user *_name) |
268 | { |
269 | char *name; |
270 | long ret; |
271 | |
272 | /* fetch the name from userspace */ |
273 | name = NULL; |
274 | if (_name) { |
275 | name = strndup_user(_name, PAGE_SIZE); |
276 | if (IS_ERR(name)) { |
277 | ret = PTR_ERR(name); |
278 | goto error; |
279 | } |
280 | } |
281 | |
282 | /* join the session */ |
283 | ret = join_session_keyring(name); |
284 | kfree(name); |
285 | |
286 | error: |
287 | return ret; |
288 | } |
289 | |
290 | /* |
291 | * Update a key's data payload from the given data. |
292 | * |
293 | * The key must grant the caller Write permission and the key type must support |
294 | * updating for this to work. A negative key can be positively instantiated |
295 | * with this call. |
296 | * |
297 | * If successful, 0 will be returned. If the key type does not support |
298 | * updating, then -EOPNOTSUPP will be returned. |
299 | */ |
300 | long keyctl_update_key(key_serial_t id, |
301 | const void __user *_payload, |
302 | size_t plen) |
303 | { |
304 | key_ref_t key_ref; |
305 | void *payload; |
306 | long ret; |
307 | |
308 | ret = -EINVAL; |
309 | if (plen > PAGE_SIZE) |
310 | goto error; |
311 | |
312 | /* pull the payload in if one was supplied */ |
313 | payload = NULL; |
314 | if (_payload) { |
315 | ret = -ENOMEM; |
316 | payload = kmalloc(plen, GFP_KERNEL); |
317 | if (!payload) |
318 | goto error; |
319 | |
320 | ret = -EFAULT; |
321 | if (copy_from_user(payload, _payload, plen) != 0) |
322 | goto error2; |
323 | } |
324 | |
325 | /* find the target key (which must be writable) */ |
326 | key_ref = lookup_user_key(id, 0, KEY_WRITE); |
327 | if (IS_ERR(key_ref)) { |
328 | ret = PTR_ERR(key_ref); |
329 | goto error2; |
330 | } |
331 | |
332 | /* update the key */ |
333 | ret = key_update(key_ref, payload, plen); |
334 | |
335 | key_ref_put(key_ref); |
336 | error2: |
337 | kfree(payload); |
338 | error: |
339 | return ret; |
340 | } |
341 | |
342 | /* |
343 | * Revoke a key. |
344 | * |
345 | * The key must be grant the caller Write or Setattr permission for this to |
346 | * work. The key type should give up its quota claim when revoked. The key |
347 | * and any links to the key will be automatically garbage collected after a |
348 | * certain amount of time (/proc/sys/kernel/keys/gc_delay). |
349 | * |
350 | * If successful, 0 is returned. |
351 | */ |
352 | long keyctl_revoke_key(key_serial_t id) |
353 | { |
354 | key_ref_t key_ref; |
355 | long ret; |
356 | |
357 | key_ref = lookup_user_key(id, 0, KEY_WRITE); |
358 | if (IS_ERR(key_ref)) { |
359 | ret = PTR_ERR(key_ref); |
360 | if (ret != -EACCES) |
361 | goto error; |
362 | key_ref = lookup_user_key(id, 0, KEY_SETATTR); |
363 | if (IS_ERR(key_ref)) { |
364 | ret = PTR_ERR(key_ref); |
365 | goto error; |
366 | } |
367 | } |
368 | |
369 | key_revoke(key_ref_to_ptr(key_ref)); |
370 | ret = 0; |
371 | |
372 | key_ref_put(key_ref); |
373 | error: |
374 | return ret; |
375 | } |
376 | |
377 | /* |
378 | * Invalidate a key. |
379 | * |
380 | * The key must be grant the caller Invalidate permission for this to work. |
381 | * The key and any links to the key will be automatically garbage collected |
382 | * immediately. |
383 | * |
384 | * If successful, 0 is returned. |
385 | */ |
386 | long keyctl_invalidate_key(key_serial_t id) |
387 | { |
388 | key_ref_t key_ref; |
389 | long ret; |
390 | |
391 | kenter("%d", id); |
392 | |
393 | key_ref = lookup_user_key(id, 0, KEY_SEARCH); |
394 | if (IS_ERR(key_ref)) { |
395 | ret = PTR_ERR(key_ref); |
396 | goto error; |
397 | } |
398 | |
399 | key_invalidate(key_ref_to_ptr(key_ref)); |
400 | ret = 0; |
401 | |
402 | key_ref_put(key_ref); |
403 | error: |
404 | kleave(" = %ld", ret); |
405 | return ret; |
406 | } |
407 | |
408 | /* |
409 | * Clear the specified keyring, creating an empty process keyring if one of the |
410 | * special keyring IDs is used. |
411 | * |
412 | * The keyring must grant the caller Write permission for this to work. If |
413 | * successful, 0 will be returned. |
414 | */ |
415 | long keyctl_keyring_clear(key_serial_t ringid) |
416 | { |
417 | key_ref_t keyring_ref; |
418 | long ret; |
419 | |
420 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
421 | if (IS_ERR(keyring_ref)) { |
422 | ret = PTR_ERR(keyring_ref); |
423 | |
424 | /* Root is permitted to invalidate certain special keyrings */ |
425 | if (capable(CAP_SYS_ADMIN)) { |
426 | keyring_ref = lookup_user_key(ringid, 0, 0); |
427 | if (IS_ERR(keyring_ref)) |
428 | goto error; |
429 | if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR, |
430 | &key_ref_to_ptr(keyring_ref)->flags)) |
431 | goto clear; |
432 | goto error_put; |
433 | } |
434 | |
435 | goto error; |
436 | } |
437 | |
438 | clear: |
439 | ret = keyring_clear(key_ref_to_ptr(keyring_ref)); |
440 | error_put: |
441 | key_ref_put(keyring_ref); |
442 | error: |
443 | return ret; |
444 | } |
445 | |
446 | /* |
447 | * Create a link from a keyring to a key if there's no matching key in the |
448 | * keyring, otherwise replace the link to the matching key with a link to the |
449 | * new key. |
450 | * |
451 | * The key must grant the caller Link permission and the the keyring must grant |
452 | * the caller Write permission. Furthermore, if an additional link is created, |
453 | * the keyring's quota will be extended. |
454 | * |
455 | * If successful, 0 will be returned. |
456 | */ |
457 | long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) |
458 | { |
459 | key_ref_t keyring_ref, key_ref; |
460 | long ret; |
461 | |
462 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
463 | if (IS_ERR(keyring_ref)) { |
464 | ret = PTR_ERR(keyring_ref); |
465 | goto error; |
466 | } |
467 | |
468 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK); |
469 | if (IS_ERR(key_ref)) { |
470 | ret = PTR_ERR(key_ref); |
471 | goto error2; |
472 | } |
473 | |
474 | ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); |
475 | |
476 | key_ref_put(key_ref); |
477 | error2: |
478 | key_ref_put(keyring_ref); |
479 | error: |
480 | return ret; |
481 | } |
482 | |
483 | /* |
484 | * Unlink a key from a keyring. |
485 | * |
486 | * The keyring must grant the caller Write permission for this to work; the key |
487 | * itself need not grant the caller anything. If the last link to a key is |
488 | * removed then that key will be scheduled for destruction. |
489 | * |
490 | * If successful, 0 will be returned. |
491 | */ |
492 | long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) |
493 | { |
494 | key_ref_t keyring_ref, key_ref; |
495 | long ret; |
496 | |
497 | keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE); |
498 | if (IS_ERR(keyring_ref)) { |
499 | ret = PTR_ERR(keyring_ref); |
500 | goto error; |
501 | } |
502 | |
503 | key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0); |
504 | if (IS_ERR(key_ref)) { |
505 | ret = PTR_ERR(key_ref); |
506 | goto error2; |
507 | } |
508 | |
509 | ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); |
510 | |
511 | key_ref_put(key_ref); |
512 | error2: |
513 | key_ref_put(keyring_ref); |
514 | error: |
515 | return ret; |
516 | } |
517 | |
518 | /* |
519 | * Return a description of a key to userspace. |
520 | * |
521 | * The key must grant the caller View permission for this to work. |
522 | * |
523 | * If there's a buffer, we place up to buflen bytes of data into it formatted |
524 | * in the following way: |
525 | * |
526 | * type;uid;gid;perm;description<NUL> |
527 | * |
528 | * If successful, we return the amount of description available, irrespective |
529 | * of how much we may have copied into the buffer. |
530 | */ |
531 | long keyctl_describe_key(key_serial_t keyid, |
532 | char __user *buffer, |
533 | size_t buflen) |
534 | { |
535 | struct key *key, *instkey; |
536 | key_ref_t key_ref; |
537 | char *tmpbuf; |
538 | long ret; |
539 | |
540 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); |
541 | if (IS_ERR(key_ref)) { |
542 | /* viewing a key under construction is permitted if we have the |
543 | * authorisation token handy */ |
544 | if (PTR_ERR(key_ref) == -EACCES) { |
545 | instkey = key_get_instantiation_authkey(keyid); |
546 | if (!IS_ERR(instkey)) { |
547 | key_put(instkey); |
548 | key_ref = lookup_user_key(keyid, |
549 | KEY_LOOKUP_PARTIAL, |
550 | 0); |
551 | if (!IS_ERR(key_ref)) |
552 | goto okay; |
553 | } |
554 | } |
555 | |
556 | ret = PTR_ERR(key_ref); |
557 | goto error; |
558 | } |
559 | |
560 | okay: |
561 | /* calculate how much description we're going to return */ |
562 | ret = -ENOMEM; |
563 | tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
564 | if (!tmpbuf) |
565 | goto error2; |
566 | |
567 | key = key_ref_to_ptr(key_ref); |
568 | |
569 | ret = snprintf(tmpbuf, PAGE_SIZE - 1, |
570 | "%s;%d;%d;%08x;%s", |
571 | key->type->name, |
572 | key->uid, |
573 | key->gid, |
574 | key->perm, |
575 | key->description ?: ""); |
576 | |
577 | /* include a NUL char at the end of the data */ |
578 | if (ret > PAGE_SIZE - 1) |
579 | ret = PAGE_SIZE - 1; |
580 | tmpbuf[ret] = 0; |
581 | ret++; |
582 | |
583 | /* consider returning the data */ |
584 | if (buffer && buflen > 0) { |
585 | if (buflen > ret) |
586 | buflen = ret; |
587 | |
588 | if (copy_to_user(buffer, tmpbuf, buflen) != 0) |
589 | ret = -EFAULT; |
590 | } |
591 | |
592 | kfree(tmpbuf); |
593 | error2: |
594 | key_ref_put(key_ref); |
595 | error: |
596 | return ret; |
597 | } |
598 | |
599 | /* |
600 | * Search the specified keyring and any keyrings it links to for a matching |
601 | * key. Only keyrings that grant the caller Search permission will be searched |
602 | * (this includes the starting keyring). Only keys with Search permission can |
603 | * be found. |
604 | * |
605 | * If successful, the found key will be linked to the destination keyring if |
606 | * supplied and the key has Link permission, and the found key ID will be |
607 | * returned. |
608 | */ |
609 | long keyctl_keyring_search(key_serial_t ringid, |
610 | const char __user *_type, |
611 | const char __user *_description, |
612 | key_serial_t destringid) |
613 | { |
614 | struct key_type *ktype; |
615 | key_ref_t keyring_ref, key_ref, dest_ref; |
616 | char type[32], *description; |
617 | long ret; |
618 | |
619 | /* pull the type and description into kernel space */ |
620 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
621 | if (ret < 0) |
622 | goto error; |
623 | |
624 | description = strndup_user(_description, PAGE_SIZE); |
625 | if (IS_ERR(description)) { |
626 | ret = PTR_ERR(description); |
627 | goto error; |
628 | } |
629 | |
630 | /* get the keyring at which to begin the search */ |
631 | keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH); |
632 | if (IS_ERR(keyring_ref)) { |
633 | ret = PTR_ERR(keyring_ref); |
634 | goto error2; |
635 | } |
636 | |
637 | /* get the destination keyring if specified */ |
638 | dest_ref = NULL; |
639 | if (destringid) { |
640 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, |
641 | KEY_WRITE); |
642 | if (IS_ERR(dest_ref)) { |
643 | ret = PTR_ERR(dest_ref); |
644 | goto error3; |
645 | } |
646 | } |
647 | |
648 | /* find the key type */ |
649 | ktype = key_type_lookup(type); |
650 | if (IS_ERR(ktype)) { |
651 | ret = PTR_ERR(ktype); |
652 | goto error4; |
653 | } |
654 | |
655 | /* do the search */ |
656 | key_ref = keyring_search(keyring_ref, ktype, description); |
657 | if (IS_ERR(key_ref)) { |
658 | ret = PTR_ERR(key_ref); |
659 | |
660 | /* treat lack or presence of a negative key the same */ |
661 | if (ret == -EAGAIN) |
662 | ret = -ENOKEY; |
663 | goto error5; |
664 | } |
665 | |
666 | /* link the resulting key to the destination keyring if we can */ |
667 | if (dest_ref) { |
668 | ret = key_permission(key_ref, KEY_LINK); |
669 | if (ret < 0) |
670 | goto error6; |
671 | |
672 | ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref)); |
673 | if (ret < 0) |
674 | goto error6; |
675 | } |
676 | |
677 | ret = key_ref_to_ptr(key_ref)->serial; |
678 | |
679 | error6: |
680 | key_ref_put(key_ref); |
681 | error5: |
682 | key_type_put(ktype); |
683 | error4: |
684 | key_ref_put(dest_ref); |
685 | error3: |
686 | key_ref_put(keyring_ref); |
687 | error2: |
688 | kfree(description); |
689 | error: |
690 | return ret; |
691 | } |
692 | |
693 | /* |
694 | * Read a key's payload. |
695 | * |
696 | * The key must either grant the caller Read permission, or it must grant the |
697 | * caller Search permission when searched for from the process keyrings. |
698 | * |
699 | * If successful, we place up to buflen bytes of data into the buffer, if one |
700 | * is provided, and return the amount of data that is available in the key, |
701 | * irrespective of how much we copied into the buffer. |
702 | */ |
703 | long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) |
704 | { |
705 | struct key *key; |
706 | key_ref_t key_ref; |
707 | long ret; |
708 | |
709 | /* find the key first */ |
710 | key_ref = lookup_user_key(keyid, 0, 0); |
711 | if (IS_ERR(key_ref)) { |
712 | ret = -ENOKEY; |
713 | goto error; |
714 | } |
715 | |
716 | key = key_ref_to_ptr(key_ref); |
717 | |
718 | /* see if we can read it directly */ |
719 | ret = key_permission(key_ref, KEY_READ); |
720 | if (ret == 0) |
721 | goto can_read_key; |
722 | if (ret != -EACCES) |
723 | goto error; |
724 | |
725 | /* we can't; see if it's searchable from this process's keyrings |
726 | * - we automatically take account of the fact that it may be |
727 | * dangling off an instantiation key |
728 | */ |
729 | if (!is_key_possessed(key_ref)) { |
730 | ret = -EACCES; |
731 | goto error2; |
732 | } |
733 | |
734 | /* the key is probably readable - now try to read it */ |
735 | can_read_key: |
736 | ret = key_validate(key); |
737 | if (ret == 0) { |
738 | ret = -EOPNOTSUPP; |
739 | if (key->type->read) { |
740 | /* read the data with the semaphore held (since we |
741 | * might sleep) */ |
742 | down_read(&key->sem); |
743 | ret = key->type->read(key, buffer, buflen); |
744 | up_read(&key->sem); |
745 | } |
746 | } |
747 | |
748 | error2: |
749 | key_put(key); |
750 | error: |
751 | return ret; |
752 | } |
753 | |
754 | /* |
755 | * Change the ownership of a key |
756 | * |
757 | * The key must grant the caller Setattr permission for this to work, though |
758 | * the key need not be fully instantiated yet. For the UID to be changed, or |
759 | * for the GID to be changed to a group the caller is not a member of, the |
760 | * caller must have sysadmin capability. If either uid or gid is -1 then that |
761 | * attribute is not changed. |
762 | * |
763 | * If the UID is to be changed, the new user must have sufficient quota to |
764 | * accept the key. The quota deduction will be removed from the old user to |
765 | * the new user should the attribute be changed. |
766 | * |
767 | * If successful, 0 will be returned. |
768 | */ |
769 | long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) |
770 | { |
771 | struct key_user *newowner, *zapowner = NULL; |
772 | struct key *key; |
773 | key_ref_t key_ref; |
774 | long ret; |
775 | |
776 | ret = 0; |
777 | if (uid == (uid_t) -1 && gid == (gid_t) -1) |
778 | goto error; |
779 | |
780 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
781 | KEY_SETATTR); |
782 | if (IS_ERR(key_ref)) { |
783 | ret = PTR_ERR(key_ref); |
784 | goto error; |
785 | } |
786 | |
787 | key = key_ref_to_ptr(key_ref); |
788 | |
789 | /* make the changes with the locks held to prevent chown/chown races */ |
790 | ret = -EACCES; |
791 | down_write(&key->sem); |
792 | |
793 | if (!capable(CAP_SYS_ADMIN)) { |
794 | /* only the sysadmin can chown a key to some other UID */ |
795 | if (uid != (uid_t) -1 && key->uid != uid) |
796 | goto error_put; |
797 | |
798 | /* only the sysadmin can set the key's GID to a group other |
799 | * than one of those that the current process subscribes to */ |
800 | if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid)) |
801 | goto error_put; |
802 | } |
803 | |
804 | /* change the UID */ |
805 | if (uid != (uid_t) -1 && uid != key->uid) { |
806 | ret = -ENOMEM; |
807 | newowner = key_user_lookup(uid, current_user_ns()); |
808 | if (!newowner) |
809 | goto error_put; |
810 | |
811 | /* transfer the quota burden to the new user */ |
812 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
813 | unsigned maxkeys = (uid == 0) ? |
814 | key_quota_root_maxkeys : key_quota_maxkeys; |
815 | unsigned maxbytes = (uid == 0) ? |
816 | key_quota_root_maxbytes : key_quota_maxbytes; |
817 | |
818 | spin_lock(&newowner->lock); |
819 | if (newowner->qnkeys + 1 >= maxkeys || |
820 | newowner->qnbytes + key->quotalen >= maxbytes || |
821 | newowner->qnbytes + key->quotalen < |
822 | newowner->qnbytes) |
823 | goto quota_overrun; |
824 | |
825 | newowner->qnkeys++; |
826 | newowner->qnbytes += key->quotalen; |
827 | spin_unlock(&newowner->lock); |
828 | |
829 | spin_lock(&key->user->lock); |
830 | key->user->qnkeys--; |
831 | key->user->qnbytes -= key->quotalen; |
832 | spin_unlock(&key->user->lock); |
833 | } |
834 | |
835 | atomic_dec(&key->user->nkeys); |
836 | atomic_inc(&newowner->nkeys); |
837 | |
838 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
839 | atomic_dec(&key->user->nikeys); |
840 | atomic_inc(&newowner->nikeys); |
841 | } |
842 | |
843 | zapowner = key->user; |
844 | key->user = newowner; |
845 | key->uid = uid; |
846 | } |
847 | |
848 | /* change the GID */ |
849 | if (gid != (gid_t) -1) |
850 | key->gid = gid; |
851 | |
852 | ret = 0; |
853 | |
854 | error_put: |
855 | up_write(&key->sem); |
856 | key_put(key); |
857 | if (zapowner) |
858 | key_user_put(zapowner); |
859 | error: |
860 | return ret; |
861 | |
862 | quota_overrun: |
863 | spin_unlock(&newowner->lock); |
864 | zapowner = newowner; |
865 | ret = -EDQUOT; |
866 | goto error_put; |
867 | } |
868 | |
869 | /* |
870 | * Change the permission mask on a key. |
871 | * |
872 | * The key must grant the caller Setattr permission for this to work, though |
873 | * the key need not be fully instantiated yet. If the caller does not have |
874 | * sysadmin capability, it may only change the permission on keys that it owns. |
875 | */ |
876 | long keyctl_setperm_key(key_serial_t id, key_perm_t perm) |
877 | { |
878 | struct key *key; |
879 | key_ref_t key_ref; |
880 | long ret; |
881 | |
882 | ret = -EINVAL; |
883 | if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) |
884 | goto error; |
885 | |
886 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
887 | KEY_SETATTR); |
888 | if (IS_ERR(key_ref)) { |
889 | ret = PTR_ERR(key_ref); |
890 | goto error; |
891 | } |
892 | |
893 | key = key_ref_to_ptr(key_ref); |
894 | |
895 | /* make the changes with the locks held to prevent chown/chmod races */ |
896 | ret = -EACCES; |
897 | down_write(&key->sem); |
898 | |
899 | /* if we're not the sysadmin, we can only change a key that we own */ |
900 | if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) { |
901 | key->perm = perm; |
902 | ret = 0; |
903 | } |
904 | |
905 | up_write(&key->sem); |
906 | key_put(key); |
907 | error: |
908 | return ret; |
909 | } |
910 | |
911 | /* |
912 | * Get the destination keyring for instantiation and check that the caller has |
913 | * Write permission on it. |
914 | */ |
915 | static long get_instantiation_keyring(key_serial_t ringid, |
916 | struct request_key_auth *rka, |
917 | struct key **_dest_keyring) |
918 | { |
919 | key_ref_t dkref; |
920 | |
921 | *_dest_keyring = NULL; |
922 | |
923 | /* just return a NULL pointer if we weren't asked to make a link */ |
924 | if (ringid == 0) |
925 | return 0; |
926 | |
927 | /* if a specific keyring is nominated by ID, then use that */ |
928 | if (ringid > 0) { |
929 | dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
930 | if (IS_ERR(dkref)) |
931 | return PTR_ERR(dkref); |
932 | *_dest_keyring = key_ref_to_ptr(dkref); |
933 | return 0; |
934 | } |
935 | |
936 | if (ringid == KEY_SPEC_REQKEY_AUTH_KEY) |
937 | return -EINVAL; |
938 | |
939 | /* otherwise specify the destination keyring recorded in the |
940 | * authorisation key (any KEY_SPEC_*_KEYRING) */ |
941 | if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) { |
942 | *_dest_keyring = key_get(rka->dest_keyring); |
943 | return 0; |
944 | } |
945 | |
946 | return -ENOKEY; |
947 | } |
948 | |
949 | /* |
950 | * Change the request_key authorisation key on the current process. |
951 | */ |
952 | static int keyctl_change_reqkey_auth(struct key *key) |
953 | { |
954 | struct cred *new; |
955 | |
956 | new = prepare_creds(); |
957 | if (!new) |
958 | return -ENOMEM; |
959 | |
960 | key_put(new->request_key_auth); |
961 | new->request_key_auth = key_get(key); |
962 | |
963 | return commit_creds(new); |
964 | } |
965 | |
966 | /* |
967 | * Copy the iovec data from userspace |
968 | */ |
969 | static long copy_from_user_iovec(void *buffer, const struct iovec *iov, |
970 | unsigned ioc) |
971 | { |
972 | for (; ioc > 0; ioc--) { |
973 | if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0) |
974 | return -EFAULT; |
975 | buffer += iov->iov_len; |
976 | iov++; |
977 | } |
978 | return 0; |
979 | } |
980 | |
981 | /* |
982 | * Instantiate a key with the specified payload and link the key into the |
983 | * destination keyring if one is given. |
984 | * |
985 | * The caller must have the appropriate instantiation permit set for this to |
986 | * work (see keyctl_assume_authority). No other permissions are required. |
987 | * |
988 | * If successful, 0 will be returned. |
989 | */ |
990 | long keyctl_instantiate_key_common(key_serial_t id, |
991 | const struct iovec *payload_iov, |
992 | unsigned ioc, |
993 | size_t plen, |
994 | key_serial_t ringid) |
995 | { |
996 | const struct cred *cred = current_cred(); |
997 | struct request_key_auth *rka; |
998 | struct key *instkey, *dest_keyring; |
999 | void *payload; |
1000 | long ret; |
1001 | bool vm = false; |
1002 | |
1003 | kenter("%d,,%zu,%d", id, plen, ringid); |
1004 | |
1005 | ret = -EINVAL; |
1006 | if (plen > 1024 * 1024 - 1) |
1007 | goto error; |
1008 | |
1009 | /* the appropriate instantiation authorisation key must have been |
1010 | * assumed before calling this */ |
1011 | ret = -EPERM; |
1012 | instkey = cred->request_key_auth; |
1013 | if (!instkey) |
1014 | goto error; |
1015 | |
1016 | rka = instkey->payload.data; |
1017 | if (rka->target_key->serial != id) |
1018 | goto error; |
1019 | |
1020 | /* pull the payload in if one was supplied */ |
1021 | payload = NULL; |
1022 | |
1023 | if (payload_iov) { |
1024 | ret = -ENOMEM; |
1025 | payload = kmalloc(plen, GFP_KERNEL); |
1026 | if (!payload) { |
1027 | if (plen <= PAGE_SIZE) |
1028 | goto error; |
1029 | vm = true; |
1030 | payload = vmalloc(plen); |
1031 | if (!payload) |
1032 | goto error; |
1033 | } |
1034 | |
1035 | ret = copy_from_user_iovec(payload, payload_iov, ioc); |
1036 | if (ret < 0) |
1037 | goto error2; |
1038 | } |
1039 | |
1040 | /* find the destination keyring amongst those belonging to the |
1041 | * requesting task */ |
1042 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); |
1043 | if (ret < 0) |
1044 | goto error2; |
1045 | |
1046 | /* instantiate the key and link it into a keyring */ |
1047 | ret = key_instantiate_and_link(rka->target_key, payload, plen, |
1048 | dest_keyring, instkey); |
1049 | |
1050 | key_put(dest_keyring); |
1051 | |
1052 | /* discard the assumed authority if it's just been disabled by |
1053 | * instantiation of the key */ |
1054 | if (ret == 0) |
1055 | keyctl_change_reqkey_auth(NULL); |
1056 | |
1057 | error2: |
1058 | if (!vm) |
1059 | kfree(payload); |
1060 | else |
1061 | vfree(payload); |
1062 | error: |
1063 | return ret; |
1064 | } |
1065 | |
1066 | /* |
1067 | * Instantiate a key with the specified payload and link the key into the |
1068 | * destination keyring if one is given. |
1069 | * |
1070 | * The caller must have the appropriate instantiation permit set for this to |
1071 | * work (see keyctl_assume_authority). No other permissions are required. |
1072 | * |
1073 | * If successful, 0 will be returned. |
1074 | */ |
1075 | long keyctl_instantiate_key(key_serial_t id, |
1076 | const void __user *_payload, |
1077 | size_t plen, |
1078 | key_serial_t ringid) |
1079 | { |
1080 | if (_payload && plen) { |
1081 | struct iovec iov[1] = { |
1082 | [0].iov_base = (void __user *)_payload, |
1083 | [0].iov_len = plen |
1084 | }; |
1085 | |
1086 | return keyctl_instantiate_key_common(id, iov, 1, plen, ringid); |
1087 | } |
1088 | |
1089 | return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); |
1090 | } |
1091 | |
1092 | /* |
1093 | * Instantiate a key with the specified multipart payload and link the key into |
1094 | * the destination keyring if one is given. |
1095 | * |
1096 | * The caller must have the appropriate instantiation permit set for this to |
1097 | * work (see keyctl_assume_authority). No other permissions are required. |
1098 | * |
1099 | * If successful, 0 will be returned. |
1100 | */ |
1101 | long keyctl_instantiate_key_iov(key_serial_t id, |
1102 | const struct iovec __user *_payload_iov, |
1103 | unsigned ioc, |
1104 | key_serial_t ringid) |
1105 | { |
1106 | struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; |
1107 | long ret; |
1108 | |
1109 | if (!_payload_iov || !ioc) |
1110 | goto no_payload; |
1111 | |
1112 | ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc, |
1113 | ARRAY_SIZE(iovstack), iovstack, &iov); |
1114 | if (ret < 0) |
1115 | return ret; |
1116 | if (ret == 0) |
1117 | goto no_payload_free; |
1118 | |
1119 | ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); |
1120 | |
1121 | if (iov != iovstack) |
1122 | kfree(iov); |
1123 | return ret; |
1124 | |
1125 | no_payload_free: |
1126 | if (iov != iovstack) |
1127 | kfree(iov); |
1128 | no_payload: |
1129 | return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); |
1130 | } |
1131 | |
1132 | /* |
1133 | * Negatively instantiate the key with the given timeout (in seconds) and link |
1134 | * the key into the destination keyring if one is given. |
1135 | * |
1136 | * The caller must have the appropriate instantiation permit set for this to |
1137 | * work (see keyctl_assume_authority). No other permissions are required. |
1138 | * |
1139 | * The key and any links to the key will be automatically garbage collected |
1140 | * after the timeout expires. |
1141 | * |
1142 | * Negative keys are used to rate limit repeated request_key() calls by causing |
1143 | * them to return -ENOKEY until the negative key expires. |
1144 | * |
1145 | * If successful, 0 will be returned. |
1146 | */ |
1147 | long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) |
1148 | { |
1149 | return keyctl_reject_key(id, timeout, ENOKEY, ringid); |
1150 | } |
1151 | |
1152 | /* |
1153 | * Negatively instantiate the key with the given timeout (in seconds) and error |
1154 | * code and link the key into the destination keyring if one is given. |
1155 | * |
1156 | * The caller must have the appropriate instantiation permit set for this to |
1157 | * work (see keyctl_assume_authority). No other permissions are required. |
1158 | * |
1159 | * The key and any links to the key will be automatically garbage collected |
1160 | * after the timeout expires. |
1161 | * |
1162 | * Negative keys are used to rate limit repeated request_key() calls by causing |
1163 | * them to return the specified error code until the negative key expires. |
1164 | * |
1165 | * If successful, 0 will be returned. |
1166 | */ |
1167 | long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, |
1168 | key_serial_t ringid) |
1169 | { |
1170 | const struct cred *cred = current_cred(); |
1171 | struct request_key_auth *rka; |
1172 | struct key *instkey, *dest_keyring; |
1173 | long ret; |
1174 | |
1175 | kenter("%d,%u,%u,%d", id, timeout, error, ringid); |
1176 | |
1177 | /* must be a valid error code and mustn't be a kernel special */ |
1178 | if (error <= 0 || |
1179 | error >= MAX_ERRNO || |
1180 | error == ERESTARTSYS || |
1181 | error == ERESTARTNOINTR || |
1182 | error == ERESTARTNOHAND || |
1183 | error == ERESTART_RESTARTBLOCK) |
1184 | return -EINVAL; |
1185 | |
1186 | /* the appropriate instantiation authorisation key must have been |
1187 | * assumed before calling this */ |
1188 | ret = -EPERM; |
1189 | instkey = cred->request_key_auth; |
1190 | if (!instkey) |
1191 | goto error; |
1192 | |
1193 | rka = instkey->payload.data; |
1194 | if (rka->target_key->serial != id) |
1195 | goto error; |
1196 | |
1197 | /* find the destination keyring if present (which must also be |
1198 | * writable) */ |
1199 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); |
1200 | if (ret < 0) |
1201 | goto error; |
1202 | |
1203 | /* instantiate the key and link it into a keyring */ |
1204 | ret = key_reject_and_link(rka->target_key, timeout, error, |
1205 | dest_keyring, instkey); |
1206 | |
1207 | key_put(dest_keyring); |
1208 | |
1209 | /* discard the assumed authority if it's just been disabled by |
1210 | * instantiation of the key */ |
1211 | if (ret == 0) |
1212 | keyctl_change_reqkey_auth(NULL); |
1213 | |
1214 | error: |
1215 | return ret; |
1216 | } |
1217 | |
1218 | /* |
1219 | * Read or set the default keyring in which request_key() will cache keys and |
1220 | * return the old setting. |
1221 | * |
1222 | * If a process keyring is specified then this will be created if it doesn't |
1223 | * yet exist. The old setting will be returned if successful. |
1224 | */ |
1225 | long keyctl_set_reqkey_keyring(int reqkey_defl) |
1226 | { |
1227 | struct cred *new; |
1228 | int ret, old_setting; |
1229 | |
1230 | old_setting = current_cred_xxx(jit_keyring); |
1231 | |
1232 | if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE) |
1233 | return old_setting; |
1234 | |
1235 | new = prepare_creds(); |
1236 | if (!new) |
1237 | return -ENOMEM; |
1238 | |
1239 | switch (reqkey_defl) { |
1240 | case KEY_REQKEY_DEFL_THREAD_KEYRING: |
1241 | ret = install_thread_keyring_to_cred(new); |
1242 | if (ret < 0) |
1243 | goto error; |
1244 | goto set; |
1245 | |
1246 | case KEY_REQKEY_DEFL_PROCESS_KEYRING: |
1247 | ret = install_process_keyring_to_cred(new); |
1248 | if (ret < 0) { |
1249 | if (ret != -EEXIST) |
1250 | goto error; |
1251 | ret = 0; |
1252 | } |
1253 | goto set; |
1254 | |
1255 | case KEY_REQKEY_DEFL_DEFAULT: |
1256 | case KEY_REQKEY_DEFL_SESSION_KEYRING: |
1257 | case KEY_REQKEY_DEFL_USER_KEYRING: |
1258 | case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: |
1259 | case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: |
1260 | goto set; |
1261 | |
1262 | case KEY_REQKEY_DEFL_NO_CHANGE: |
1263 | case KEY_REQKEY_DEFL_GROUP_KEYRING: |
1264 | default: |
1265 | ret = -EINVAL; |
1266 | goto error; |
1267 | } |
1268 | |
1269 | set: |
1270 | new->jit_keyring = reqkey_defl; |
1271 | commit_creds(new); |
1272 | return old_setting; |
1273 | error: |
1274 | abort_creds(new); |
1275 | return ret; |
1276 | } |
1277 | |
1278 | /* |
1279 | * Set or clear the timeout on a key. |
1280 | * |
1281 | * Either the key must grant the caller Setattr permission or else the caller |
1282 | * must hold an instantiation authorisation token for the key. |
1283 | * |
1284 | * The timeout is either 0 to clear the timeout, or a number of seconds from |
1285 | * the current time. The key and any links to the key will be automatically |
1286 | * garbage collected after the timeout expires. |
1287 | * |
1288 | * If successful, 0 is returned. |
1289 | */ |
1290 | long keyctl_set_timeout(key_serial_t id, unsigned timeout) |
1291 | { |
1292 | struct key *key, *instkey; |
1293 | key_ref_t key_ref; |
1294 | long ret; |
1295 | |
1296 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
1297 | KEY_SETATTR); |
1298 | if (IS_ERR(key_ref)) { |
1299 | /* setting the timeout on a key under construction is permitted |
1300 | * if we have the authorisation token handy */ |
1301 | if (PTR_ERR(key_ref) == -EACCES) { |
1302 | instkey = key_get_instantiation_authkey(id); |
1303 | if (!IS_ERR(instkey)) { |
1304 | key_put(instkey); |
1305 | key_ref = lookup_user_key(id, |
1306 | KEY_LOOKUP_PARTIAL, |
1307 | 0); |
1308 | if (!IS_ERR(key_ref)) |
1309 | goto okay; |
1310 | } |
1311 | } |
1312 | |
1313 | ret = PTR_ERR(key_ref); |
1314 | goto error; |
1315 | } |
1316 | |
1317 | okay: |
1318 | key = key_ref_to_ptr(key_ref); |
1319 | key_set_timeout(key, timeout); |
1320 | key_put(key); |
1321 | |
1322 | ret = 0; |
1323 | error: |
1324 | return ret; |
1325 | } |
1326 | |
1327 | /* |
1328 | * Assume (or clear) the authority to instantiate the specified key. |
1329 | * |
1330 | * This sets the authoritative token currently in force for key instantiation. |
1331 | * This must be done for a key to be instantiated. It has the effect of making |
1332 | * available all the keys from the caller of the request_key() that created a |
1333 | * key to request_key() calls made by the caller of this function. |
1334 | * |
1335 | * The caller must have the instantiation key in their process keyrings with a |
1336 | * Search permission grant available to the caller. |
1337 | * |
1338 | * If the ID given is 0, then the setting will be cleared and 0 returned. |
1339 | * |
1340 | * If the ID given has a matching an authorisation key, then that key will be |
1341 | * set and its ID will be returned. The authorisation key can be read to get |
1342 | * the callout information passed to request_key(). |
1343 | */ |
1344 | long keyctl_assume_authority(key_serial_t id) |
1345 | { |
1346 | struct key *authkey; |
1347 | long ret; |
1348 | |
1349 | /* special key IDs aren't permitted */ |
1350 | ret = -EINVAL; |
1351 | if (id < 0) |
1352 | goto error; |
1353 | |
1354 | /* we divest ourselves of authority if given an ID of 0 */ |
1355 | if (id == 0) { |
1356 | ret = keyctl_change_reqkey_auth(NULL); |
1357 | goto error; |
1358 | } |
1359 | |
1360 | /* attempt to assume the authority temporarily granted to us whilst we |
1361 | * instantiate the specified key |
1362 | * - the authorisation key must be in the current task's keyrings |
1363 | * somewhere |
1364 | */ |
1365 | authkey = key_get_instantiation_authkey(id); |
1366 | if (IS_ERR(authkey)) { |
1367 | ret = PTR_ERR(authkey); |
1368 | goto error; |
1369 | } |
1370 | |
1371 | ret = keyctl_change_reqkey_auth(authkey); |
1372 | if (ret < 0) |
1373 | goto error; |
1374 | key_put(authkey); |
1375 | |
1376 | ret = authkey->serial; |
1377 | error: |
1378 | return ret; |
1379 | } |
1380 | |
1381 | /* |
1382 | * Get a key's the LSM security label. |
1383 | * |
1384 | * The key must grant the caller View permission for this to work. |
1385 | * |
1386 | * If there's a buffer, then up to buflen bytes of data will be placed into it. |
1387 | * |
1388 | * If successful, the amount of information available will be returned, |
1389 | * irrespective of how much was copied (including the terminal NUL). |
1390 | */ |
1391 | long keyctl_get_security(key_serial_t keyid, |
1392 | char __user *buffer, |
1393 | size_t buflen) |
1394 | { |
1395 | struct key *key, *instkey; |
1396 | key_ref_t key_ref; |
1397 | char *context; |
1398 | long ret; |
1399 | |
1400 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); |
1401 | if (IS_ERR(key_ref)) { |
1402 | if (PTR_ERR(key_ref) != -EACCES) |
1403 | return PTR_ERR(key_ref); |
1404 | |
1405 | /* viewing a key under construction is also permitted if we |
1406 | * have the authorisation token handy */ |
1407 | instkey = key_get_instantiation_authkey(keyid); |
1408 | if (IS_ERR(instkey)) |
1409 | return PTR_ERR(instkey); |
1410 | key_put(instkey); |
1411 | |
1412 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0); |
1413 | if (IS_ERR(key_ref)) |
1414 | return PTR_ERR(key_ref); |
1415 | } |
1416 | |
1417 | key = key_ref_to_ptr(key_ref); |
1418 | ret = security_key_getsecurity(key, &context); |
1419 | if (ret == 0) { |
1420 | /* if no information was returned, give userspace an empty |
1421 | * string */ |
1422 | ret = 1; |
1423 | if (buffer && buflen > 0 && |
1424 | copy_to_user(buffer, "", 1) != 0) |
1425 | ret = -EFAULT; |
1426 | } else if (ret > 0) { |
1427 | /* return as much data as there's room for */ |
1428 | if (buffer && buflen > 0) { |
1429 | if (buflen > ret) |
1430 | buflen = ret; |
1431 | |
1432 | if (copy_to_user(buffer, context, buflen) != 0) |
1433 | ret = -EFAULT; |
1434 | } |
1435 | |
1436 | kfree(context); |
1437 | } |
1438 | |
1439 | key_ref_put(key_ref); |
1440 | return ret; |
1441 | } |
1442 | |
1443 | /* |
1444 | * Attempt to install the calling process's session keyring on the process's |
1445 | * parent process. |
1446 | * |
1447 | * The keyring must exist and must grant the caller LINK permission, and the |
1448 | * parent process must be single-threaded and must have the same effective |
1449 | * ownership as this process and mustn't be SUID/SGID. |
1450 | * |
1451 | * The keyring will be emplaced on the parent when it next resumes userspace. |
1452 | * |
1453 | * If successful, 0 will be returned. |
1454 | */ |
1455 | long keyctl_session_to_parent(void) |
1456 | { |
1457 | struct task_struct *me, *parent; |
1458 | const struct cred *mycred, *pcred; |
1459 | struct callback_head *newwork, *oldwork; |
1460 | key_ref_t keyring_r; |
1461 | struct cred *cred; |
1462 | int ret; |
1463 | |
1464 | keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK); |
1465 | if (IS_ERR(keyring_r)) |
1466 | return PTR_ERR(keyring_r); |
1467 | |
1468 | ret = -ENOMEM; |
1469 | |
1470 | /* our parent is going to need a new cred struct, a new tgcred struct |
1471 | * and new security data, so we allocate them here to prevent ENOMEM in |
1472 | * our parent */ |
1473 | cred = cred_alloc_blank(); |
1474 | if (!cred) |
1475 | goto error_keyring; |
1476 | newwork = &cred->rcu; |
1477 | |
1478 | cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r); |
1479 | init_task_work(newwork, key_change_session_keyring); |
1480 | |
1481 | me = current; |
1482 | rcu_read_lock(); |
1483 | write_lock_irq(&tasklist_lock); |
1484 | |
1485 | ret = -EPERM; |
1486 | oldwork = NULL; |
1487 | parent = me->real_parent; |
1488 | |
1489 | task_lock(parent); |
1490 | /* the parent mustn't be init and mustn't be a kernel thread */ |
1491 | if (parent->pid <= 1 || !parent->mm) |
1492 | goto unlock; |
1493 | |
1494 | /* the parent must be single threaded */ |
1495 | if (!thread_group_empty(parent)) |
1496 | goto unlock; |
1497 | |
1498 | /* the parent and the child must have different session keyrings or |
1499 | * there's no point */ |
1500 | mycred = current_cred(); |
1501 | pcred = __task_cred(parent); |
1502 | if (mycred == pcred || |
1503 | mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) { |
1504 | ret = 0; |
1505 | goto unlock; |
1506 | } |
1507 | |
1508 | /* the parent must have the same effective ownership and mustn't be |
1509 | * SUID/SGID */ |
1510 | if (pcred->uid != mycred->euid || |
1511 | pcred->euid != mycred->euid || |
1512 | pcred->suid != mycred->euid || |
1513 | pcred->gid != mycred->egid || |
1514 | pcred->egid != mycred->egid || |
1515 | pcred->sgid != mycred->egid) |
1516 | goto unlock; |
1517 | |
1518 | /* the keyrings must have the same UID */ |
1519 | if ((pcred->tgcred->session_keyring && |
1520 | pcred->tgcred->session_keyring->uid != mycred->euid) || |
1521 | mycred->tgcred->session_keyring->uid != mycred->euid) |
1522 | goto unlock; |
1523 | |
1524 | /* cancel an already pending keyring replacement */ |
1525 | oldwork = task_work_cancel(parent, key_change_session_keyring); |
1526 | |
1527 | /* the replacement session keyring is applied just prior to userspace |
1528 | * restarting */ |
1529 | ret = task_work_add(parent, newwork, true); |
1530 | if (!ret) |
1531 | newwork = NULL; |
1532 | unlock: |
1533 | task_unlock(parent); |
1534 | write_unlock_irq(&tasklist_lock); |
1535 | rcu_read_unlock(); |
1536 | if (oldwork) |
1537 | put_cred(container_of(oldwork, struct cred, rcu)); |
1538 | if (newwork) |
1539 | put_cred(cred); |
1540 | return ret; |
1541 | |
1542 | error_keyring: |
1543 | key_ref_put(keyring_r); |
1544 | return ret; |
1545 | } |
1546 | |
1547 | /* |
1548 | * The key control system call |
1549 | */ |
1550 | SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, |
1551 | unsigned long, arg4, unsigned long, arg5) |
1552 | { |
1553 | switch (option) { |
1554 | case KEYCTL_GET_KEYRING_ID: |
1555 | return keyctl_get_keyring_ID((key_serial_t) arg2, |
1556 | (int) arg3); |
1557 | |
1558 | case KEYCTL_JOIN_SESSION_KEYRING: |
1559 | return keyctl_join_session_keyring((const char __user *) arg2); |
1560 | |
1561 | case KEYCTL_UPDATE: |
1562 | return keyctl_update_key((key_serial_t) arg2, |
1563 | (const void __user *) arg3, |
1564 | (size_t) arg4); |
1565 | |
1566 | case KEYCTL_REVOKE: |
1567 | return keyctl_revoke_key((key_serial_t) arg2); |
1568 | |
1569 | case KEYCTL_DESCRIBE: |
1570 | return keyctl_describe_key((key_serial_t) arg2, |
1571 | (char __user *) arg3, |
1572 | (unsigned) arg4); |
1573 | |
1574 | case KEYCTL_CLEAR: |
1575 | return keyctl_keyring_clear((key_serial_t) arg2); |
1576 | |
1577 | case KEYCTL_LINK: |
1578 | return keyctl_keyring_link((key_serial_t) arg2, |
1579 | (key_serial_t) arg3); |
1580 | |
1581 | case KEYCTL_UNLINK: |
1582 | return keyctl_keyring_unlink((key_serial_t) arg2, |
1583 | (key_serial_t) arg3); |
1584 | |
1585 | case KEYCTL_SEARCH: |
1586 | return keyctl_keyring_search((key_serial_t) arg2, |
1587 | (const char __user *) arg3, |
1588 | (const char __user *) arg4, |
1589 | (key_serial_t) arg5); |
1590 | |
1591 | case KEYCTL_READ: |
1592 | return keyctl_read_key((key_serial_t) arg2, |
1593 | (char __user *) arg3, |
1594 | (size_t) arg4); |
1595 | |
1596 | case KEYCTL_CHOWN: |
1597 | return keyctl_chown_key((key_serial_t) arg2, |
1598 | (uid_t) arg3, |
1599 | (gid_t) arg4); |
1600 | |
1601 | case KEYCTL_SETPERM: |
1602 | return keyctl_setperm_key((key_serial_t) arg2, |
1603 | (key_perm_t) arg3); |
1604 | |
1605 | case KEYCTL_INSTANTIATE: |
1606 | return keyctl_instantiate_key((key_serial_t) arg2, |
1607 | (const void __user *) arg3, |
1608 | (size_t) arg4, |
1609 | (key_serial_t) arg5); |
1610 | |
1611 | case KEYCTL_NEGATE: |
1612 | return keyctl_negate_key((key_serial_t) arg2, |
1613 | (unsigned) arg3, |
1614 | (key_serial_t) arg4); |
1615 | |
1616 | case KEYCTL_SET_REQKEY_KEYRING: |
1617 | return keyctl_set_reqkey_keyring(arg2); |
1618 | |
1619 | case KEYCTL_SET_TIMEOUT: |
1620 | return keyctl_set_timeout((key_serial_t) arg2, |
1621 | (unsigned) arg3); |
1622 | |
1623 | case KEYCTL_ASSUME_AUTHORITY: |
1624 | return keyctl_assume_authority((key_serial_t) arg2); |
1625 | |
1626 | case KEYCTL_GET_SECURITY: |
1627 | return keyctl_get_security((key_serial_t) arg2, |
1628 | (char __user *) arg3, |
1629 | (size_t) arg4); |
1630 | |
1631 | case KEYCTL_SESSION_TO_PARENT: |
1632 | return keyctl_session_to_parent(); |
1633 | |
1634 | case KEYCTL_REJECT: |
1635 | return keyctl_reject_key((key_serial_t) arg2, |
1636 | (unsigned) arg3, |
1637 | (unsigned) arg4, |
1638 | (key_serial_t) arg5); |
1639 | |
1640 | case KEYCTL_INSTANTIATE_IOV: |
1641 | return keyctl_instantiate_key_iov( |
1642 | (key_serial_t) arg2, |
1643 | (const struct iovec __user *) arg3, |
1644 | (unsigned) arg4, |
1645 | (key_serial_t) arg5); |
1646 | |
1647 | case KEYCTL_INVALIDATE: |
1648 | return keyctl_invalidate_key((key_serial_t) arg2); |
1649 | |
1650 | default: |
1651 | return -EOPNOTSUPP; |
1652 | } |
1653 | } |
1654 |
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Tags:
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v2.6.34-rc5
v2.6.34-rc6
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v3.9