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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 | * If the description is NULL or an empty string, the key type is asked to |
50 | * generate one from the payload. |
51 | * |
52 | * The keyring must be writable so that we can attach the key to it. |
53 | * |
54 | * If successful, the new key's serial number is returned, otherwise an error |
55 | * code is returned. |
56 | */ |
57 | SYSCALL_DEFINE5(add_key, const char __user *, _type, |
58 | const char __user *, _description, |
59 | const void __user *, _payload, |
60 | size_t, plen, |
61 | key_serial_t, ringid) |
62 | { |
63 | key_ref_t keyring_ref, key_ref; |
64 | char type[32], *description; |
65 | void *payload; |
66 | long ret; |
67 | bool vm; |
68 | |
69 | ret = -EINVAL; |
70 | if (plen > 1024 * 1024 - 1) |
71 | goto error; |
72 | |
73 | /* draw all the data into kernel space */ |
74 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
75 | if (ret < 0) |
76 | goto error; |
77 | |
78 | description = NULL; |
79 | if (_description) { |
80 | description = strndup_user(_description, PAGE_SIZE); |
81 | if (IS_ERR(description)) { |
82 | ret = PTR_ERR(description); |
83 | goto error; |
84 | } |
85 | if (!*description) { |
86 | kfree(description); |
87 | description = NULL; |
88 | } |
89 | } |
90 | |
91 | /* pull the payload in if one was supplied */ |
92 | payload = NULL; |
93 | |
94 | vm = false; |
95 | if (_payload) { |
96 | ret = -ENOMEM; |
97 | payload = kmalloc(plen, GFP_KERNEL | __GFP_NOWARN); |
98 | if (!payload) { |
99 | if (plen <= PAGE_SIZE) |
100 | goto error2; |
101 | vm = true; |
102 | payload = vmalloc(plen); |
103 | if (!payload) |
104 | goto error2; |
105 | } |
106 | |
107 | ret = -EFAULT; |
108 | if (copy_from_user(payload, _payload, plen) != 0) |
109 | goto error3; |
110 | } |
111 | |
112 | /* find the target keyring (which must be writable) */ |
113 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
114 | if (IS_ERR(keyring_ref)) { |
115 | ret = PTR_ERR(keyring_ref); |
116 | goto error3; |
117 | } |
118 | |
119 | /* create or update the requested key and add it to the target |
120 | * keyring */ |
121 | key_ref = key_create_or_update(keyring_ref, type, description, |
122 | payload, plen, KEY_PERM_UNDEF, |
123 | KEY_ALLOC_IN_QUOTA); |
124 | if (!IS_ERR(key_ref)) { |
125 | ret = key_ref_to_ptr(key_ref)->serial; |
126 | key_ref_put(key_ref); |
127 | } |
128 | else { |
129 | ret = PTR_ERR(key_ref); |
130 | } |
131 | |
132 | key_ref_put(keyring_ref); |
133 | error3: |
134 | if (!vm) |
135 | kfree(payload); |
136 | else |
137 | vfree(payload); |
138 | error2: |
139 | kfree(description); |
140 | error: |
141 | return ret; |
142 | } |
143 | |
144 | /* |
145 | * Search the process keyrings and keyring trees linked from those for a |
146 | * matching key. Keyrings must have appropriate Search permission to be |
147 | * searched. |
148 | * |
149 | * If a key is found, it will be attached to the destination keyring if there's |
150 | * one specified and the serial number of the key will be returned. |
151 | * |
152 | * If no key is found, /sbin/request-key will be invoked if _callout_info is |
153 | * non-NULL in an attempt to create a key. The _callout_info string will be |
154 | * passed to /sbin/request-key to aid with completing the request. If the |
155 | * _callout_info string is "" then it will be changed to "-". |
156 | */ |
157 | SYSCALL_DEFINE4(request_key, const char __user *, _type, |
158 | const char __user *, _description, |
159 | const char __user *, _callout_info, |
160 | key_serial_t, destringid) |
161 | { |
162 | struct key_type *ktype; |
163 | struct key *key; |
164 | key_ref_t dest_ref; |
165 | size_t callout_len; |
166 | char type[32], *description, *callout_info; |
167 | long ret; |
168 | |
169 | /* pull the type into kernel space */ |
170 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
171 | if (ret < 0) |
172 | goto error; |
173 | |
174 | /* pull the description into kernel space */ |
175 | description = strndup_user(_description, PAGE_SIZE); |
176 | if (IS_ERR(description)) { |
177 | ret = PTR_ERR(description); |
178 | goto error; |
179 | } |
180 | |
181 | /* pull the callout info into kernel space */ |
182 | callout_info = NULL; |
183 | callout_len = 0; |
184 | if (_callout_info) { |
185 | callout_info = strndup_user(_callout_info, PAGE_SIZE); |
186 | if (IS_ERR(callout_info)) { |
187 | ret = PTR_ERR(callout_info); |
188 | goto error2; |
189 | } |
190 | callout_len = strlen(callout_info); |
191 | } |
192 | |
193 | /* get the destination keyring if specified */ |
194 | dest_ref = NULL; |
195 | if (destringid) { |
196 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, |
197 | KEY_WRITE); |
198 | if (IS_ERR(dest_ref)) { |
199 | ret = PTR_ERR(dest_ref); |
200 | goto error3; |
201 | } |
202 | } |
203 | |
204 | /* find the key type */ |
205 | ktype = key_type_lookup(type); |
206 | if (IS_ERR(ktype)) { |
207 | ret = PTR_ERR(ktype); |
208 | goto error4; |
209 | } |
210 | |
211 | /* do the search */ |
212 | key = request_key_and_link(ktype, description, callout_info, |
213 | callout_len, NULL, key_ref_to_ptr(dest_ref), |
214 | KEY_ALLOC_IN_QUOTA); |
215 | if (IS_ERR(key)) { |
216 | ret = PTR_ERR(key); |
217 | goto error5; |
218 | } |
219 | |
220 | /* wait for the key to finish being constructed */ |
221 | ret = wait_for_key_construction(key, 1); |
222 | if (ret < 0) |
223 | goto error6; |
224 | |
225 | ret = key->serial; |
226 | |
227 | error6: |
228 | key_put(key); |
229 | error5: |
230 | key_type_put(ktype); |
231 | error4: |
232 | key_ref_put(dest_ref); |
233 | error3: |
234 | kfree(callout_info); |
235 | error2: |
236 | kfree(description); |
237 | error: |
238 | return ret; |
239 | } |
240 | |
241 | /* |
242 | * Get the ID of the specified process keyring. |
243 | * |
244 | * The requested keyring must have search permission to be found. |
245 | * |
246 | * If successful, the ID of the requested keyring will be returned. |
247 | */ |
248 | long keyctl_get_keyring_ID(key_serial_t id, int create) |
249 | { |
250 | key_ref_t key_ref; |
251 | unsigned long lflags; |
252 | long ret; |
253 | |
254 | lflags = create ? KEY_LOOKUP_CREATE : 0; |
255 | key_ref = lookup_user_key(id, lflags, KEY_SEARCH); |
256 | if (IS_ERR(key_ref)) { |
257 | ret = PTR_ERR(key_ref); |
258 | goto error; |
259 | } |
260 | |
261 | ret = key_ref_to_ptr(key_ref)->serial; |
262 | key_ref_put(key_ref); |
263 | error: |
264 | return ret; |
265 | } |
266 | |
267 | /* |
268 | * Join a (named) session keyring. |
269 | * |
270 | * Create and join an anonymous session keyring or join a named session |
271 | * keyring, creating it if necessary. A named session keyring must have Search |
272 | * permission for it to be joined. Session keyrings without this permit will |
273 | * be skipped over. |
274 | * |
275 | * If successful, the ID of the joined session keyring will be returned. |
276 | */ |
277 | long keyctl_join_session_keyring(const char __user *_name) |
278 | { |
279 | char *name; |
280 | long ret; |
281 | |
282 | /* fetch the name from userspace */ |
283 | name = NULL; |
284 | if (_name) { |
285 | name = strndup_user(_name, PAGE_SIZE); |
286 | if (IS_ERR(name)) { |
287 | ret = PTR_ERR(name); |
288 | goto error; |
289 | } |
290 | } |
291 | |
292 | /* join the session */ |
293 | ret = join_session_keyring(name); |
294 | kfree(name); |
295 | |
296 | error: |
297 | return ret; |
298 | } |
299 | |
300 | /* |
301 | * Update a key's data payload from the given data. |
302 | * |
303 | * The key must grant the caller Write permission and the key type must support |
304 | * updating for this to work. A negative key can be positively instantiated |
305 | * with this call. |
306 | * |
307 | * If successful, 0 will be returned. If the key type does not support |
308 | * updating, then -EOPNOTSUPP will be returned. |
309 | */ |
310 | long keyctl_update_key(key_serial_t id, |
311 | const void __user *_payload, |
312 | size_t plen) |
313 | { |
314 | key_ref_t key_ref; |
315 | void *payload; |
316 | long ret; |
317 | |
318 | ret = -EINVAL; |
319 | if (plen > PAGE_SIZE) |
320 | goto error; |
321 | |
322 | /* pull the payload in if one was supplied */ |
323 | payload = NULL; |
324 | if (_payload) { |
325 | ret = -ENOMEM; |
326 | payload = kmalloc(plen, GFP_KERNEL); |
327 | if (!payload) |
328 | goto error; |
329 | |
330 | ret = -EFAULT; |
331 | if (copy_from_user(payload, _payload, plen) != 0) |
332 | goto error2; |
333 | } |
334 | |
335 | /* find the target key (which must be writable) */ |
336 | key_ref = lookup_user_key(id, 0, KEY_WRITE); |
337 | if (IS_ERR(key_ref)) { |
338 | ret = PTR_ERR(key_ref); |
339 | goto error2; |
340 | } |
341 | |
342 | /* update the key */ |
343 | ret = key_update(key_ref, payload, plen); |
344 | |
345 | key_ref_put(key_ref); |
346 | error2: |
347 | kfree(payload); |
348 | error: |
349 | return ret; |
350 | } |
351 | |
352 | /* |
353 | * Revoke a key. |
354 | * |
355 | * The key must be grant the caller Write or Setattr permission for this to |
356 | * work. The key type should give up its quota claim when revoked. The key |
357 | * and any links to the key will be automatically garbage collected after a |
358 | * certain amount of time (/proc/sys/kernel/keys/gc_delay). |
359 | * |
360 | * If successful, 0 is returned. |
361 | */ |
362 | long keyctl_revoke_key(key_serial_t id) |
363 | { |
364 | key_ref_t key_ref; |
365 | long ret; |
366 | |
367 | key_ref = lookup_user_key(id, 0, KEY_WRITE); |
368 | if (IS_ERR(key_ref)) { |
369 | ret = PTR_ERR(key_ref); |
370 | if (ret != -EACCES) |
371 | goto error; |
372 | key_ref = lookup_user_key(id, 0, KEY_SETATTR); |
373 | if (IS_ERR(key_ref)) { |
374 | ret = PTR_ERR(key_ref); |
375 | goto error; |
376 | } |
377 | } |
378 | |
379 | key_revoke(key_ref_to_ptr(key_ref)); |
380 | ret = 0; |
381 | |
382 | key_ref_put(key_ref); |
383 | error: |
384 | return ret; |
385 | } |
386 | |
387 | /* |
388 | * Invalidate a key. |
389 | * |
390 | * The key must be grant the caller Invalidate permission for this to work. |
391 | * The key and any links to the key will be automatically garbage collected |
392 | * immediately. |
393 | * |
394 | * If successful, 0 is returned. |
395 | */ |
396 | long keyctl_invalidate_key(key_serial_t id) |
397 | { |
398 | key_ref_t key_ref; |
399 | long ret; |
400 | |
401 | kenter("%d", id); |
402 | |
403 | key_ref = lookup_user_key(id, 0, KEY_SEARCH); |
404 | if (IS_ERR(key_ref)) { |
405 | ret = PTR_ERR(key_ref); |
406 | goto error; |
407 | } |
408 | |
409 | key_invalidate(key_ref_to_ptr(key_ref)); |
410 | ret = 0; |
411 | |
412 | key_ref_put(key_ref); |
413 | error: |
414 | kleave(" = %ld", ret); |
415 | return ret; |
416 | } |
417 | |
418 | /* |
419 | * Clear the specified keyring, creating an empty process keyring if one of the |
420 | * special keyring IDs is used. |
421 | * |
422 | * The keyring must grant the caller Write permission for this to work. If |
423 | * successful, 0 will be returned. |
424 | */ |
425 | long keyctl_keyring_clear(key_serial_t ringid) |
426 | { |
427 | key_ref_t keyring_ref; |
428 | long ret; |
429 | |
430 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
431 | if (IS_ERR(keyring_ref)) { |
432 | ret = PTR_ERR(keyring_ref); |
433 | |
434 | /* Root is permitted to invalidate certain special keyrings */ |
435 | if (capable(CAP_SYS_ADMIN)) { |
436 | keyring_ref = lookup_user_key(ringid, 0, 0); |
437 | if (IS_ERR(keyring_ref)) |
438 | goto error; |
439 | if (test_bit(KEY_FLAG_ROOT_CAN_CLEAR, |
440 | &key_ref_to_ptr(keyring_ref)->flags)) |
441 | goto clear; |
442 | goto error_put; |
443 | } |
444 | |
445 | goto error; |
446 | } |
447 | |
448 | clear: |
449 | ret = keyring_clear(key_ref_to_ptr(keyring_ref)); |
450 | error_put: |
451 | key_ref_put(keyring_ref); |
452 | error: |
453 | return ret; |
454 | } |
455 | |
456 | /* |
457 | * Create a link from a keyring to a key if there's no matching key in the |
458 | * keyring, otherwise replace the link to the matching key with a link to the |
459 | * new key. |
460 | * |
461 | * The key must grant the caller Link permission and the the keyring must grant |
462 | * the caller Write permission. Furthermore, if an additional link is created, |
463 | * the keyring's quota will be extended. |
464 | * |
465 | * If successful, 0 will be returned. |
466 | */ |
467 | long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) |
468 | { |
469 | key_ref_t keyring_ref, key_ref; |
470 | long ret; |
471 | |
472 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
473 | if (IS_ERR(keyring_ref)) { |
474 | ret = PTR_ERR(keyring_ref); |
475 | goto error; |
476 | } |
477 | |
478 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK); |
479 | if (IS_ERR(key_ref)) { |
480 | ret = PTR_ERR(key_ref); |
481 | goto error2; |
482 | } |
483 | |
484 | ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); |
485 | |
486 | key_ref_put(key_ref); |
487 | error2: |
488 | key_ref_put(keyring_ref); |
489 | error: |
490 | return ret; |
491 | } |
492 | |
493 | /* |
494 | * Unlink a key from a keyring. |
495 | * |
496 | * The keyring must grant the caller Write permission for this to work; the key |
497 | * itself need not grant the caller anything. If the last link to a key is |
498 | * removed then that key will be scheduled for destruction. |
499 | * |
500 | * If successful, 0 will be returned. |
501 | */ |
502 | long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) |
503 | { |
504 | key_ref_t keyring_ref, key_ref; |
505 | long ret; |
506 | |
507 | keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE); |
508 | if (IS_ERR(keyring_ref)) { |
509 | ret = PTR_ERR(keyring_ref); |
510 | goto error; |
511 | } |
512 | |
513 | key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0); |
514 | if (IS_ERR(key_ref)) { |
515 | ret = PTR_ERR(key_ref); |
516 | goto error2; |
517 | } |
518 | |
519 | ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); |
520 | |
521 | key_ref_put(key_ref); |
522 | error2: |
523 | key_ref_put(keyring_ref); |
524 | error: |
525 | return ret; |
526 | } |
527 | |
528 | /* |
529 | * Return a description of a key to userspace. |
530 | * |
531 | * The key must grant the caller View permission for this to work. |
532 | * |
533 | * If there's a buffer, we place up to buflen bytes of data into it formatted |
534 | * in the following way: |
535 | * |
536 | * type;uid;gid;perm;description<NUL> |
537 | * |
538 | * If successful, we return the amount of description available, irrespective |
539 | * of how much we may have copied into the buffer. |
540 | */ |
541 | long keyctl_describe_key(key_serial_t keyid, |
542 | char __user *buffer, |
543 | size_t buflen) |
544 | { |
545 | struct key *key, *instkey; |
546 | key_ref_t key_ref; |
547 | char *tmpbuf; |
548 | long ret; |
549 | |
550 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); |
551 | if (IS_ERR(key_ref)) { |
552 | /* viewing a key under construction is permitted if we have the |
553 | * authorisation token handy */ |
554 | if (PTR_ERR(key_ref) == -EACCES) { |
555 | instkey = key_get_instantiation_authkey(keyid); |
556 | if (!IS_ERR(instkey)) { |
557 | key_put(instkey); |
558 | key_ref = lookup_user_key(keyid, |
559 | KEY_LOOKUP_PARTIAL, |
560 | 0); |
561 | if (!IS_ERR(key_ref)) |
562 | goto okay; |
563 | } |
564 | } |
565 | |
566 | ret = PTR_ERR(key_ref); |
567 | goto error; |
568 | } |
569 | |
570 | okay: |
571 | /* calculate how much description we're going to return */ |
572 | ret = -ENOMEM; |
573 | tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); |
574 | if (!tmpbuf) |
575 | goto error2; |
576 | |
577 | key = key_ref_to_ptr(key_ref); |
578 | |
579 | ret = snprintf(tmpbuf, PAGE_SIZE - 1, |
580 | "%s;%d;%d;%08x;%s", |
581 | key->type->name, |
582 | from_kuid_munged(current_user_ns(), key->uid), |
583 | from_kgid_munged(current_user_ns(), key->gid), |
584 | key->perm, |
585 | key->description ?: ""); |
586 | |
587 | /* include a NUL char at the end of the data */ |
588 | if (ret > PAGE_SIZE - 1) |
589 | ret = PAGE_SIZE - 1; |
590 | tmpbuf[ret] = 0; |
591 | ret++; |
592 | |
593 | /* consider returning the data */ |
594 | if (buffer && buflen > 0) { |
595 | if (buflen > ret) |
596 | buflen = ret; |
597 | |
598 | if (copy_to_user(buffer, tmpbuf, buflen) != 0) |
599 | ret = -EFAULT; |
600 | } |
601 | |
602 | kfree(tmpbuf); |
603 | error2: |
604 | key_ref_put(key_ref); |
605 | error: |
606 | return ret; |
607 | } |
608 | |
609 | /* |
610 | * Search the specified keyring and any keyrings it links to for a matching |
611 | * key. Only keyrings that grant the caller Search permission will be searched |
612 | * (this includes the starting keyring). Only keys with Search permission can |
613 | * be found. |
614 | * |
615 | * If successful, the found key will be linked to the destination keyring if |
616 | * supplied and the key has Link permission, and the found key ID will be |
617 | * returned. |
618 | */ |
619 | long keyctl_keyring_search(key_serial_t ringid, |
620 | const char __user *_type, |
621 | const char __user *_description, |
622 | key_serial_t destringid) |
623 | { |
624 | struct key_type *ktype; |
625 | key_ref_t keyring_ref, key_ref, dest_ref; |
626 | char type[32], *description; |
627 | long ret; |
628 | |
629 | /* pull the type and description into kernel space */ |
630 | ret = key_get_type_from_user(type, _type, sizeof(type)); |
631 | if (ret < 0) |
632 | goto error; |
633 | |
634 | description = strndup_user(_description, PAGE_SIZE); |
635 | if (IS_ERR(description)) { |
636 | ret = PTR_ERR(description); |
637 | goto error; |
638 | } |
639 | |
640 | /* get the keyring at which to begin the search */ |
641 | keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH); |
642 | if (IS_ERR(keyring_ref)) { |
643 | ret = PTR_ERR(keyring_ref); |
644 | goto error2; |
645 | } |
646 | |
647 | /* get the destination keyring if specified */ |
648 | dest_ref = NULL; |
649 | if (destringid) { |
650 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, |
651 | KEY_WRITE); |
652 | if (IS_ERR(dest_ref)) { |
653 | ret = PTR_ERR(dest_ref); |
654 | goto error3; |
655 | } |
656 | } |
657 | |
658 | /* find the key type */ |
659 | ktype = key_type_lookup(type); |
660 | if (IS_ERR(ktype)) { |
661 | ret = PTR_ERR(ktype); |
662 | goto error4; |
663 | } |
664 | |
665 | /* do the search */ |
666 | key_ref = keyring_search(keyring_ref, ktype, description); |
667 | if (IS_ERR(key_ref)) { |
668 | ret = PTR_ERR(key_ref); |
669 | |
670 | /* treat lack or presence of a negative key the same */ |
671 | if (ret == -EAGAIN) |
672 | ret = -ENOKEY; |
673 | goto error5; |
674 | } |
675 | |
676 | /* link the resulting key to the destination keyring if we can */ |
677 | if (dest_ref) { |
678 | ret = key_permission(key_ref, KEY_LINK); |
679 | if (ret < 0) |
680 | goto error6; |
681 | |
682 | ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref)); |
683 | if (ret < 0) |
684 | goto error6; |
685 | } |
686 | |
687 | ret = key_ref_to_ptr(key_ref)->serial; |
688 | |
689 | error6: |
690 | key_ref_put(key_ref); |
691 | error5: |
692 | key_type_put(ktype); |
693 | error4: |
694 | key_ref_put(dest_ref); |
695 | error3: |
696 | key_ref_put(keyring_ref); |
697 | error2: |
698 | kfree(description); |
699 | error: |
700 | return ret; |
701 | } |
702 | |
703 | /* |
704 | * Read a key's payload. |
705 | * |
706 | * The key must either grant the caller Read permission, or it must grant the |
707 | * caller Search permission when searched for from the process keyrings. |
708 | * |
709 | * If successful, we place up to buflen bytes of data into the buffer, if one |
710 | * is provided, and return the amount of data that is available in the key, |
711 | * irrespective of how much we copied into the buffer. |
712 | */ |
713 | long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) |
714 | { |
715 | struct key *key; |
716 | key_ref_t key_ref; |
717 | long ret; |
718 | |
719 | /* find the key first */ |
720 | key_ref = lookup_user_key(keyid, 0, 0); |
721 | if (IS_ERR(key_ref)) { |
722 | ret = -ENOKEY; |
723 | goto error; |
724 | } |
725 | |
726 | key = key_ref_to_ptr(key_ref); |
727 | |
728 | /* see if we can read it directly */ |
729 | ret = key_permission(key_ref, KEY_READ); |
730 | if (ret == 0) |
731 | goto can_read_key; |
732 | if (ret != -EACCES) |
733 | goto error; |
734 | |
735 | /* we can't; see if it's searchable from this process's keyrings |
736 | * - we automatically take account of the fact that it may be |
737 | * dangling off an instantiation key |
738 | */ |
739 | if (!is_key_possessed(key_ref)) { |
740 | ret = -EACCES; |
741 | goto error2; |
742 | } |
743 | |
744 | /* the key is probably readable - now try to read it */ |
745 | can_read_key: |
746 | ret = key_validate(key); |
747 | if (ret == 0) { |
748 | ret = -EOPNOTSUPP; |
749 | if (key->type->read) { |
750 | /* read the data with the semaphore held (since we |
751 | * might sleep) */ |
752 | down_read(&key->sem); |
753 | ret = key->type->read(key, buffer, buflen); |
754 | up_read(&key->sem); |
755 | } |
756 | } |
757 | |
758 | error2: |
759 | key_put(key); |
760 | error: |
761 | return ret; |
762 | } |
763 | |
764 | /* |
765 | * Change the ownership of a key |
766 | * |
767 | * The key must grant the caller Setattr permission for this to work, though |
768 | * the key need not be fully instantiated yet. For the UID to be changed, or |
769 | * for the GID to be changed to a group the caller is not a member of, the |
770 | * caller must have sysadmin capability. If either uid or gid is -1 then that |
771 | * attribute is not changed. |
772 | * |
773 | * If the UID is to be changed, the new user must have sufficient quota to |
774 | * accept the key. The quota deduction will be removed from the old user to |
775 | * the new user should the attribute be changed. |
776 | * |
777 | * If successful, 0 will be returned. |
778 | */ |
779 | long keyctl_chown_key(key_serial_t id, uid_t user, gid_t group) |
780 | { |
781 | struct key_user *newowner, *zapowner = NULL; |
782 | struct key *key; |
783 | key_ref_t key_ref; |
784 | long ret; |
785 | kuid_t uid; |
786 | kgid_t gid; |
787 | |
788 | uid = make_kuid(current_user_ns(), user); |
789 | gid = make_kgid(current_user_ns(), group); |
790 | ret = -EINVAL; |
791 | if ((user != (uid_t) -1) && !uid_valid(uid)) |
792 | goto error; |
793 | if ((group != (gid_t) -1) && !gid_valid(gid)) |
794 | goto error; |
795 | |
796 | ret = 0; |
797 | if (user == (uid_t) -1 && group == (gid_t) -1) |
798 | goto error; |
799 | |
800 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
801 | KEY_SETATTR); |
802 | if (IS_ERR(key_ref)) { |
803 | ret = PTR_ERR(key_ref); |
804 | goto error; |
805 | } |
806 | |
807 | key = key_ref_to_ptr(key_ref); |
808 | |
809 | /* make the changes with the locks held to prevent chown/chown races */ |
810 | ret = -EACCES; |
811 | down_write(&key->sem); |
812 | |
813 | if (!capable(CAP_SYS_ADMIN)) { |
814 | /* only the sysadmin can chown a key to some other UID */ |
815 | if (user != (uid_t) -1 && !uid_eq(key->uid, uid)) |
816 | goto error_put; |
817 | |
818 | /* only the sysadmin can set the key's GID to a group other |
819 | * than one of those that the current process subscribes to */ |
820 | if (group != (gid_t) -1 && !gid_eq(gid, key->gid) && !in_group_p(gid)) |
821 | goto error_put; |
822 | } |
823 | |
824 | /* change the UID */ |
825 | if (user != (uid_t) -1 && !uid_eq(uid, key->uid)) { |
826 | ret = -ENOMEM; |
827 | newowner = key_user_lookup(uid); |
828 | if (!newowner) |
829 | goto error_put; |
830 | |
831 | /* transfer the quota burden to the new user */ |
832 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { |
833 | unsigned maxkeys = uid_eq(uid, GLOBAL_ROOT_UID) ? |
834 | key_quota_root_maxkeys : key_quota_maxkeys; |
835 | unsigned maxbytes = uid_eq(uid, GLOBAL_ROOT_UID) ? |
836 | key_quota_root_maxbytes : key_quota_maxbytes; |
837 | |
838 | spin_lock(&newowner->lock); |
839 | if (newowner->qnkeys + 1 >= maxkeys || |
840 | newowner->qnbytes + key->quotalen >= maxbytes || |
841 | newowner->qnbytes + key->quotalen < |
842 | newowner->qnbytes) |
843 | goto quota_overrun; |
844 | |
845 | newowner->qnkeys++; |
846 | newowner->qnbytes += key->quotalen; |
847 | spin_unlock(&newowner->lock); |
848 | |
849 | spin_lock(&key->user->lock); |
850 | key->user->qnkeys--; |
851 | key->user->qnbytes -= key->quotalen; |
852 | spin_unlock(&key->user->lock); |
853 | } |
854 | |
855 | atomic_dec(&key->user->nkeys); |
856 | atomic_inc(&newowner->nkeys); |
857 | |
858 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { |
859 | atomic_dec(&key->user->nikeys); |
860 | atomic_inc(&newowner->nikeys); |
861 | } |
862 | |
863 | zapowner = key->user; |
864 | key->user = newowner; |
865 | key->uid = uid; |
866 | } |
867 | |
868 | /* change the GID */ |
869 | if (group != (gid_t) -1) |
870 | key->gid = gid; |
871 | |
872 | ret = 0; |
873 | |
874 | error_put: |
875 | up_write(&key->sem); |
876 | key_put(key); |
877 | if (zapowner) |
878 | key_user_put(zapowner); |
879 | error: |
880 | return ret; |
881 | |
882 | quota_overrun: |
883 | spin_unlock(&newowner->lock); |
884 | zapowner = newowner; |
885 | ret = -EDQUOT; |
886 | goto error_put; |
887 | } |
888 | |
889 | /* |
890 | * Change the permission mask on a key. |
891 | * |
892 | * The key must grant the caller Setattr permission for this to work, though |
893 | * the key need not be fully instantiated yet. If the caller does not have |
894 | * sysadmin capability, it may only change the permission on keys that it owns. |
895 | */ |
896 | long keyctl_setperm_key(key_serial_t id, key_perm_t perm) |
897 | { |
898 | struct key *key; |
899 | key_ref_t key_ref; |
900 | long ret; |
901 | |
902 | ret = -EINVAL; |
903 | if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) |
904 | goto error; |
905 | |
906 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
907 | KEY_SETATTR); |
908 | if (IS_ERR(key_ref)) { |
909 | ret = PTR_ERR(key_ref); |
910 | goto error; |
911 | } |
912 | |
913 | key = key_ref_to_ptr(key_ref); |
914 | |
915 | /* make the changes with the locks held to prevent chown/chmod races */ |
916 | ret = -EACCES; |
917 | down_write(&key->sem); |
918 | |
919 | /* if we're not the sysadmin, we can only change a key that we own */ |
920 | if (capable(CAP_SYS_ADMIN) || uid_eq(key->uid, current_fsuid())) { |
921 | key->perm = perm; |
922 | ret = 0; |
923 | } |
924 | |
925 | up_write(&key->sem); |
926 | key_put(key); |
927 | error: |
928 | return ret; |
929 | } |
930 | |
931 | /* |
932 | * Get the destination keyring for instantiation and check that the caller has |
933 | * Write permission on it. |
934 | */ |
935 | static long get_instantiation_keyring(key_serial_t ringid, |
936 | struct request_key_auth *rka, |
937 | struct key **_dest_keyring) |
938 | { |
939 | key_ref_t dkref; |
940 | |
941 | *_dest_keyring = NULL; |
942 | |
943 | /* just return a NULL pointer if we weren't asked to make a link */ |
944 | if (ringid == 0) |
945 | return 0; |
946 | |
947 | /* if a specific keyring is nominated by ID, then use that */ |
948 | if (ringid > 0) { |
949 | dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); |
950 | if (IS_ERR(dkref)) |
951 | return PTR_ERR(dkref); |
952 | *_dest_keyring = key_ref_to_ptr(dkref); |
953 | return 0; |
954 | } |
955 | |
956 | if (ringid == KEY_SPEC_REQKEY_AUTH_KEY) |
957 | return -EINVAL; |
958 | |
959 | /* otherwise specify the destination keyring recorded in the |
960 | * authorisation key (any KEY_SPEC_*_KEYRING) */ |
961 | if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) { |
962 | *_dest_keyring = key_get(rka->dest_keyring); |
963 | return 0; |
964 | } |
965 | |
966 | return -ENOKEY; |
967 | } |
968 | |
969 | /* |
970 | * Change the request_key authorisation key on the current process. |
971 | */ |
972 | static int keyctl_change_reqkey_auth(struct key *key) |
973 | { |
974 | struct cred *new; |
975 | |
976 | new = prepare_creds(); |
977 | if (!new) |
978 | return -ENOMEM; |
979 | |
980 | key_put(new->request_key_auth); |
981 | new->request_key_auth = key_get(key); |
982 | |
983 | return commit_creds(new); |
984 | } |
985 | |
986 | /* |
987 | * Copy the iovec data from userspace |
988 | */ |
989 | static long copy_from_user_iovec(void *buffer, const struct iovec *iov, |
990 | unsigned ioc) |
991 | { |
992 | for (; ioc > 0; ioc--) { |
993 | if (copy_from_user(buffer, iov->iov_base, iov->iov_len) != 0) |
994 | return -EFAULT; |
995 | buffer += iov->iov_len; |
996 | iov++; |
997 | } |
998 | return 0; |
999 | } |
1000 | |
1001 | /* |
1002 | * Instantiate a key with the specified payload and link the key into the |
1003 | * destination keyring if one is given. |
1004 | * |
1005 | * The caller must have the appropriate instantiation permit set for this to |
1006 | * work (see keyctl_assume_authority). No other permissions are required. |
1007 | * |
1008 | * If successful, 0 will be returned. |
1009 | */ |
1010 | long keyctl_instantiate_key_common(key_serial_t id, |
1011 | const struct iovec *payload_iov, |
1012 | unsigned ioc, |
1013 | size_t plen, |
1014 | key_serial_t ringid) |
1015 | { |
1016 | const struct cred *cred = current_cred(); |
1017 | struct request_key_auth *rka; |
1018 | struct key *instkey, *dest_keyring; |
1019 | void *payload; |
1020 | long ret; |
1021 | bool vm = false; |
1022 | |
1023 | kenter("%d,,%zu,%d", id, plen, ringid); |
1024 | |
1025 | ret = -EINVAL; |
1026 | if (plen > 1024 * 1024 - 1) |
1027 | goto error; |
1028 | |
1029 | /* the appropriate instantiation authorisation key must have been |
1030 | * assumed before calling this */ |
1031 | ret = -EPERM; |
1032 | instkey = cred->request_key_auth; |
1033 | if (!instkey) |
1034 | goto error; |
1035 | |
1036 | rka = instkey->payload.data; |
1037 | if (rka->target_key->serial != id) |
1038 | goto error; |
1039 | |
1040 | /* pull the payload in if one was supplied */ |
1041 | payload = NULL; |
1042 | |
1043 | if (payload_iov) { |
1044 | ret = -ENOMEM; |
1045 | payload = kmalloc(plen, GFP_KERNEL); |
1046 | if (!payload) { |
1047 | if (plen <= PAGE_SIZE) |
1048 | goto error; |
1049 | vm = true; |
1050 | payload = vmalloc(plen); |
1051 | if (!payload) |
1052 | goto error; |
1053 | } |
1054 | |
1055 | ret = copy_from_user_iovec(payload, payload_iov, ioc); |
1056 | if (ret < 0) |
1057 | goto error2; |
1058 | } |
1059 | |
1060 | /* find the destination keyring amongst those belonging to the |
1061 | * requesting task */ |
1062 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); |
1063 | if (ret < 0) |
1064 | goto error2; |
1065 | |
1066 | /* instantiate the key and link it into a keyring */ |
1067 | ret = key_instantiate_and_link(rka->target_key, payload, plen, |
1068 | dest_keyring, instkey); |
1069 | |
1070 | key_put(dest_keyring); |
1071 | |
1072 | /* discard the assumed authority if it's just been disabled by |
1073 | * instantiation of the key */ |
1074 | if (ret == 0) |
1075 | keyctl_change_reqkey_auth(NULL); |
1076 | |
1077 | error2: |
1078 | if (!vm) |
1079 | kfree(payload); |
1080 | else |
1081 | vfree(payload); |
1082 | error: |
1083 | return ret; |
1084 | } |
1085 | |
1086 | /* |
1087 | * Instantiate a key with the specified payload and link the key into the |
1088 | * destination keyring if one is given. |
1089 | * |
1090 | * The caller must have the appropriate instantiation permit set for this to |
1091 | * work (see keyctl_assume_authority). No other permissions are required. |
1092 | * |
1093 | * If successful, 0 will be returned. |
1094 | */ |
1095 | long keyctl_instantiate_key(key_serial_t id, |
1096 | const void __user *_payload, |
1097 | size_t plen, |
1098 | key_serial_t ringid) |
1099 | { |
1100 | if (_payload && plen) { |
1101 | struct iovec iov[1] = { |
1102 | [0].iov_base = (void __user *)_payload, |
1103 | [0].iov_len = plen |
1104 | }; |
1105 | |
1106 | return keyctl_instantiate_key_common(id, iov, 1, plen, ringid); |
1107 | } |
1108 | |
1109 | return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); |
1110 | } |
1111 | |
1112 | /* |
1113 | * Instantiate a key with the specified multipart payload and link the key into |
1114 | * the destination keyring if one is given. |
1115 | * |
1116 | * The caller must have the appropriate instantiation permit set for this to |
1117 | * work (see keyctl_assume_authority). No other permissions are required. |
1118 | * |
1119 | * If successful, 0 will be returned. |
1120 | */ |
1121 | long keyctl_instantiate_key_iov(key_serial_t id, |
1122 | const struct iovec __user *_payload_iov, |
1123 | unsigned ioc, |
1124 | key_serial_t ringid) |
1125 | { |
1126 | struct iovec iovstack[UIO_FASTIOV], *iov = iovstack; |
1127 | long ret; |
1128 | |
1129 | if (!_payload_iov || !ioc) |
1130 | goto no_payload; |
1131 | |
1132 | ret = rw_copy_check_uvector(WRITE, _payload_iov, ioc, |
1133 | ARRAY_SIZE(iovstack), iovstack, &iov); |
1134 | if (ret < 0) |
1135 | goto err; |
1136 | if (ret == 0) |
1137 | goto no_payload_free; |
1138 | |
1139 | ret = keyctl_instantiate_key_common(id, iov, ioc, ret, ringid); |
1140 | err: |
1141 | if (iov != iovstack) |
1142 | kfree(iov); |
1143 | return ret; |
1144 | |
1145 | no_payload_free: |
1146 | if (iov != iovstack) |
1147 | kfree(iov); |
1148 | no_payload: |
1149 | return keyctl_instantiate_key_common(id, NULL, 0, 0, ringid); |
1150 | } |
1151 | |
1152 | /* |
1153 | * Negatively instantiate the key with the given timeout (in seconds) and link |
1154 | * 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 -ENOKEY until the negative key expires. |
1164 | * |
1165 | * If successful, 0 will be returned. |
1166 | */ |
1167 | long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) |
1168 | { |
1169 | return keyctl_reject_key(id, timeout, ENOKEY, ringid); |
1170 | } |
1171 | |
1172 | /* |
1173 | * Negatively instantiate the key with the given timeout (in seconds) and error |
1174 | * code and link the key into the destination keyring if one is given. |
1175 | * |
1176 | * The caller must have the appropriate instantiation permit set for this to |
1177 | * work (see keyctl_assume_authority). No other permissions are required. |
1178 | * |
1179 | * The key and any links to the key will be automatically garbage collected |
1180 | * after the timeout expires. |
1181 | * |
1182 | * Negative keys are used to rate limit repeated request_key() calls by causing |
1183 | * them to return the specified error code until the negative key expires. |
1184 | * |
1185 | * If successful, 0 will be returned. |
1186 | */ |
1187 | long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, |
1188 | key_serial_t ringid) |
1189 | { |
1190 | const struct cred *cred = current_cred(); |
1191 | struct request_key_auth *rka; |
1192 | struct key *instkey, *dest_keyring; |
1193 | long ret; |
1194 | |
1195 | kenter("%d,%u,%u,%d", id, timeout, error, ringid); |
1196 | |
1197 | /* must be a valid error code and mustn't be a kernel special */ |
1198 | if (error <= 0 || |
1199 | error >= MAX_ERRNO || |
1200 | error == ERESTARTSYS || |
1201 | error == ERESTARTNOINTR || |
1202 | error == ERESTARTNOHAND || |
1203 | error == ERESTART_RESTARTBLOCK) |
1204 | return -EINVAL; |
1205 | |
1206 | /* the appropriate instantiation authorisation key must have been |
1207 | * assumed before calling this */ |
1208 | ret = -EPERM; |
1209 | instkey = cred->request_key_auth; |
1210 | if (!instkey) |
1211 | goto error; |
1212 | |
1213 | rka = instkey->payload.data; |
1214 | if (rka->target_key->serial != id) |
1215 | goto error; |
1216 | |
1217 | /* find the destination keyring if present (which must also be |
1218 | * writable) */ |
1219 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); |
1220 | if (ret < 0) |
1221 | goto error; |
1222 | |
1223 | /* instantiate the key and link it into a keyring */ |
1224 | ret = key_reject_and_link(rka->target_key, timeout, error, |
1225 | dest_keyring, instkey); |
1226 | |
1227 | key_put(dest_keyring); |
1228 | |
1229 | /* discard the assumed authority if it's just been disabled by |
1230 | * instantiation of the key */ |
1231 | if (ret == 0) |
1232 | keyctl_change_reqkey_auth(NULL); |
1233 | |
1234 | error: |
1235 | return ret; |
1236 | } |
1237 | |
1238 | /* |
1239 | * Read or set the default keyring in which request_key() will cache keys and |
1240 | * return the old setting. |
1241 | * |
1242 | * If a process keyring is specified then this will be created if it doesn't |
1243 | * yet exist. The old setting will be returned if successful. |
1244 | */ |
1245 | long keyctl_set_reqkey_keyring(int reqkey_defl) |
1246 | { |
1247 | struct cred *new; |
1248 | int ret, old_setting; |
1249 | |
1250 | old_setting = current_cred_xxx(jit_keyring); |
1251 | |
1252 | if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE) |
1253 | return old_setting; |
1254 | |
1255 | new = prepare_creds(); |
1256 | if (!new) |
1257 | return -ENOMEM; |
1258 | |
1259 | switch (reqkey_defl) { |
1260 | case KEY_REQKEY_DEFL_THREAD_KEYRING: |
1261 | ret = install_thread_keyring_to_cred(new); |
1262 | if (ret < 0) |
1263 | goto error; |
1264 | goto set; |
1265 | |
1266 | case KEY_REQKEY_DEFL_PROCESS_KEYRING: |
1267 | ret = install_process_keyring_to_cred(new); |
1268 | if (ret < 0) { |
1269 | if (ret != -EEXIST) |
1270 | goto error; |
1271 | ret = 0; |
1272 | } |
1273 | goto set; |
1274 | |
1275 | case KEY_REQKEY_DEFL_DEFAULT: |
1276 | case KEY_REQKEY_DEFL_SESSION_KEYRING: |
1277 | case KEY_REQKEY_DEFL_USER_KEYRING: |
1278 | case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: |
1279 | case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: |
1280 | goto set; |
1281 | |
1282 | case KEY_REQKEY_DEFL_NO_CHANGE: |
1283 | case KEY_REQKEY_DEFL_GROUP_KEYRING: |
1284 | default: |
1285 | ret = -EINVAL; |
1286 | goto error; |
1287 | } |
1288 | |
1289 | set: |
1290 | new->jit_keyring = reqkey_defl; |
1291 | commit_creds(new); |
1292 | return old_setting; |
1293 | error: |
1294 | abort_creds(new); |
1295 | return ret; |
1296 | } |
1297 | |
1298 | /* |
1299 | * Set or clear the timeout on a key. |
1300 | * |
1301 | * Either the key must grant the caller Setattr permission or else the caller |
1302 | * must hold an instantiation authorisation token for the key. |
1303 | * |
1304 | * The timeout is either 0 to clear the timeout, or a number of seconds from |
1305 | * the current time. The key and any links to the key will be automatically |
1306 | * garbage collected after the timeout expires. |
1307 | * |
1308 | * If successful, 0 is returned. |
1309 | */ |
1310 | long keyctl_set_timeout(key_serial_t id, unsigned timeout) |
1311 | { |
1312 | struct key *key, *instkey; |
1313 | key_ref_t key_ref; |
1314 | long ret; |
1315 | |
1316 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, |
1317 | KEY_SETATTR); |
1318 | if (IS_ERR(key_ref)) { |
1319 | /* setting the timeout on a key under construction is permitted |
1320 | * if we have the authorisation token handy */ |
1321 | if (PTR_ERR(key_ref) == -EACCES) { |
1322 | instkey = key_get_instantiation_authkey(id); |
1323 | if (!IS_ERR(instkey)) { |
1324 | key_put(instkey); |
1325 | key_ref = lookup_user_key(id, |
1326 | KEY_LOOKUP_PARTIAL, |
1327 | 0); |
1328 | if (!IS_ERR(key_ref)) |
1329 | goto okay; |
1330 | } |
1331 | } |
1332 | |
1333 | ret = PTR_ERR(key_ref); |
1334 | goto error; |
1335 | } |
1336 | |
1337 | okay: |
1338 | key = key_ref_to_ptr(key_ref); |
1339 | key_set_timeout(key, timeout); |
1340 | key_put(key); |
1341 | |
1342 | ret = 0; |
1343 | error: |
1344 | return ret; |
1345 | } |
1346 | |
1347 | /* |
1348 | * Assume (or clear) the authority to instantiate the specified key. |
1349 | * |
1350 | * This sets the authoritative token currently in force for key instantiation. |
1351 | * This must be done for a key to be instantiated. It has the effect of making |
1352 | * available all the keys from the caller of the request_key() that created a |
1353 | * key to request_key() calls made by the caller of this function. |
1354 | * |
1355 | * The caller must have the instantiation key in their process keyrings with a |
1356 | * Search permission grant available to the caller. |
1357 | * |
1358 | * If the ID given is 0, then the setting will be cleared and 0 returned. |
1359 | * |
1360 | * If the ID given has a matching an authorisation key, then that key will be |
1361 | * set and its ID will be returned. The authorisation key can be read to get |
1362 | * the callout information passed to request_key(). |
1363 | */ |
1364 | long keyctl_assume_authority(key_serial_t id) |
1365 | { |
1366 | struct key *authkey; |
1367 | long ret; |
1368 | |
1369 | /* special key IDs aren't permitted */ |
1370 | ret = -EINVAL; |
1371 | if (id < 0) |
1372 | goto error; |
1373 | |
1374 | /* we divest ourselves of authority if given an ID of 0 */ |
1375 | if (id == 0) { |
1376 | ret = keyctl_change_reqkey_auth(NULL); |
1377 | goto error; |
1378 | } |
1379 | |
1380 | /* attempt to assume the authority temporarily granted to us whilst we |
1381 | * instantiate the specified key |
1382 | * - the authorisation key must be in the current task's keyrings |
1383 | * somewhere |
1384 | */ |
1385 | authkey = key_get_instantiation_authkey(id); |
1386 | if (IS_ERR(authkey)) { |
1387 | ret = PTR_ERR(authkey); |
1388 | goto error; |
1389 | } |
1390 | |
1391 | ret = keyctl_change_reqkey_auth(authkey); |
1392 | if (ret < 0) |
1393 | goto error; |
1394 | key_put(authkey); |
1395 | |
1396 | ret = authkey->serial; |
1397 | error: |
1398 | return ret; |
1399 | } |
1400 | |
1401 | /* |
1402 | * Get a key's the LSM security label. |
1403 | * |
1404 | * The key must grant the caller View permission for this to work. |
1405 | * |
1406 | * If there's a buffer, then up to buflen bytes of data will be placed into it. |
1407 | * |
1408 | * If successful, the amount of information available will be returned, |
1409 | * irrespective of how much was copied (including the terminal NUL). |
1410 | */ |
1411 | long keyctl_get_security(key_serial_t keyid, |
1412 | char __user *buffer, |
1413 | size_t buflen) |
1414 | { |
1415 | struct key *key, *instkey; |
1416 | key_ref_t key_ref; |
1417 | char *context; |
1418 | long ret; |
1419 | |
1420 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); |
1421 | if (IS_ERR(key_ref)) { |
1422 | if (PTR_ERR(key_ref) != -EACCES) |
1423 | return PTR_ERR(key_ref); |
1424 | |
1425 | /* viewing a key under construction is also permitted if we |
1426 | * have the authorisation token handy */ |
1427 | instkey = key_get_instantiation_authkey(keyid); |
1428 | if (IS_ERR(instkey)) |
1429 | return PTR_ERR(instkey); |
1430 | key_put(instkey); |
1431 | |
1432 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0); |
1433 | if (IS_ERR(key_ref)) |
1434 | return PTR_ERR(key_ref); |
1435 | } |
1436 | |
1437 | key = key_ref_to_ptr(key_ref); |
1438 | ret = security_key_getsecurity(key, &context); |
1439 | if (ret == 0) { |
1440 | /* if no information was returned, give userspace an empty |
1441 | * string */ |
1442 | ret = 1; |
1443 | if (buffer && buflen > 0 && |
1444 | copy_to_user(buffer, "", 1) != 0) |
1445 | ret = -EFAULT; |
1446 | } else if (ret > 0) { |
1447 | /* return as much data as there's room for */ |
1448 | if (buffer && buflen > 0) { |
1449 | if (buflen > ret) |
1450 | buflen = ret; |
1451 | |
1452 | if (copy_to_user(buffer, context, buflen) != 0) |
1453 | ret = -EFAULT; |
1454 | } |
1455 | |
1456 | kfree(context); |
1457 | } |
1458 | |
1459 | key_ref_put(key_ref); |
1460 | return ret; |
1461 | } |
1462 | |
1463 | /* |
1464 | * Attempt to install the calling process's session keyring on the process's |
1465 | * parent process. |
1466 | * |
1467 | * The keyring must exist and must grant the caller LINK permission, and the |
1468 | * parent process must be single-threaded and must have the same effective |
1469 | * ownership as this process and mustn't be SUID/SGID. |
1470 | * |
1471 | * The keyring will be emplaced on the parent when it next resumes userspace. |
1472 | * |
1473 | * If successful, 0 will be returned. |
1474 | */ |
1475 | long keyctl_session_to_parent(void) |
1476 | { |
1477 | struct task_struct *me, *parent; |
1478 | const struct cred *mycred, *pcred; |
1479 | struct callback_head *newwork, *oldwork; |
1480 | key_ref_t keyring_r; |
1481 | struct cred *cred; |
1482 | int ret; |
1483 | |
1484 | keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK); |
1485 | if (IS_ERR(keyring_r)) |
1486 | return PTR_ERR(keyring_r); |
1487 | |
1488 | ret = -ENOMEM; |
1489 | |
1490 | /* our parent is going to need a new cred struct, a new tgcred struct |
1491 | * and new security data, so we allocate them here to prevent ENOMEM in |
1492 | * our parent */ |
1493 | cred = cred_alloc_blank(); |
1494 | if (!cred) |
1495 | goto error_keyring; |
1496 | newwork = &cred->rcu; |
1497 | |
1498 | cred->session_keyring = key_ref_to_ptr(keyring_r); |
1499 | keyring_r = NULL; |
1500 | init_task_work(newwork, key_change_session_keyring); |
1501 | |
1502 | me = current; |
1503 | rcu_read_lock(); |
1504 | write_lock_irq(&tasklist_lock); |
1505 | |
1506 | ret = -EPERM; |
1507 | oldwork = NULL; |
1508 | parent = me->real_parent; |
1509 | |
1510 | /* the parent mustn't be init and mustn't be a kernel thread */ |
1511 | if (parent->pid <= 1 || !parent->mm) |
1512 | goto unlock; |
1513 | |
1514 | /* the parent must be single threaded */ |
1515 | if (!thread_group_empty(parent)) |
1516 | goto unlock; |
1517 | |
1518 | /* the parent and the child must have different session keyrings or |
1519 | * there's no point */ |
1520 | mycred = current_cred(); |
1521 | pcred = __task_cred(parent); |
1522 | if (mycred == pcred || |
1523 | mycred->session_keyring == pcred->session_keyring) { |
1524 | ret = 0; |
1525 | goto unlock; |
1526 | } |
1527 | |
1528 | /* the parent must have the same effective ownership and mustn't be |
1529 | * SUID/SGID */ |
1530 | if (!uid_eq(pcred->uid, mycred->euid) || |
1531 | !uid_eq(pcred->euid, mycred->euid) || |
1532 | !uid_eq(pcred->suid, mycred->euid) || |
1533 | !gid_eq(pcred->gid, mycred->egid) || |
1534 | !gid_eq(pcred->egid, mycred->egid) || |
1535 | !gid_eq(pcred->sgid, mycred->egid)) |
1536 | goto unlock; |
1537 | |
1538 | /* the keyrings must have the same UID */ |
1539 | if ((pcred->session_keyring && |
1540 | !uid_eq(pcred->session_keyring->uid, mycred->euid)) || |
1541 | !uid_eq(mycred->session_keyring->uid, mycred->euid)) |
1542 | goto unlock; |
1543 | |
1544 | /* cancel an already pending keyring replacement */ |
1545 | oldwork = task_work_cancel(parent, key_change_session_keyring); |
1546 | |
1547 | /* the replacement session keyring is applied just prior to userspace |
1548 | * restarting */ |
1549 | ret = task_work_add(parent, newwork, true); |
1550 | if (!ret) |
1551 | newwork = NULL; |
1552 | unlock: |
1553 | write_unlock_irq(&tasklist_lock); |
1554 | rcu_read_unlock(); |
1555 | if (oldwork) |
1556 | put_cred(container_of(oldwork, struct cred, rcu)); |
1557 | if (newwork) |
1558 | put_cred(cred); |
1559 | return ret; |
1560 | |
1561 | error_keyring: |
1562 | key_ref_put(keyring_r); |
1563 | return ret; |
1564 | } |
1565 | |
1566 | /* |
1567 | * The key control system call |
1568 | */ |
1569 | SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, |
1570 | unsigned long, arg4, unsigned long, arg5) |
1571 | { |
1572 | switch (option) { |
1573 | case KEYCTL_GET_KEYRING_ID: |
1574 | return keyctl_get_keyring_ID((key_serial_t) arg2, |
1575 | (int) arg3); |
1576 | |
1577 | case KEYCTL_JOIN_SESSION_KEYRING: |
1578 | return keyctl_join_session_keyring((const char __user *) arg2); |
1579 | |
1580 | case KEYCTL_UPDATE: |
1581 | return keyctl_update_key((key_serial_t) arg2, |
1582 | (const void __user *) arg3, |
1583 | (size_t) arg4); |
1584 | |
1585 | case KEYCTL_REVOKE: |
1586 | return keyctl_revoke_key((key_serial_t) arg2); |
1587 | |
1588 | case KEYCTL_DESCRIBE: |
1589 | return keyctl_describe_key((key_serial_t) arg2, |
1590 | (char __user *) arg3, |
1591 | (unsigned) arg4); |
1592 | |
1593 | case KEYCTL_CLEAR: |
1594 | return keyctl_keyring_clear((key_serial_t) arg2); |
1595 | |
1596 | case KEYCTL_LINK: |
1597 | return keyctl_keyring_link((key_serial_t) arg2, |
1598 | (key_serial_t) arg3); |
1599 | |
1600 | case KEYCTL_UNLINK: |
1601 | return keyctl_keyring_unlink((key_serial_t) arg2, |
1602 | (key_serial_t) arg3); |
1603 | |
1604 | case KEYCTL_SEARCH: |
1605 | return keyctl_keyring_search((key_serial_t) arg2, |
1606 | (const char __user *) arg3, |
1607 | (const char __user *) arg4, |
1608 | (key_serial_t) arg5); |
1609 | |
1610 | case KEYCTL_READ: |
1611 | return keyctl_read_key((key_serial_t) arg2, |
1612 | (char __user *) arg3, |
1613 | (size_t) arg4); |
1614 | |
1615 | case KEYCTL_CHOWN: |
1616 | return keyctl_chown_key((key_serial_t) arg2, |
1617 | (uid_t) arg3, |
1618 | (gid_t) arg4); |
1619 | |
1620 | case KEYCTL_SETPERM: |
1621 | return keyctl_setperm_key((key_serial_t) arg2, |
1622 | (key_perm_t) arg3); |
1623 | |
1624 | case KEYCTL_INSTANTIATE: |
1625 | return keyctl_instantiate_key((key_serial_t) arg2, |
1626 | (const void __user *) arg3, |
1627 | (size_t) arg4, |
1628 | (key_serial_t) arg5); |
1629 | |
1630 | case KEYCTL_NEGATE: |
1631 | return keyctl_negate_key((key_serial_t) arg2, |
1632 | (unsigned) arg3, |
1633 | (key_serial_t) arg4); |
1634 | |
1635 | case KEYCTL_SET_REQKEY_KEYRING: |
1636 | return keyctl_set_reqkey_keyring(arg2); |
1637 | |
1638 | case KEYCTL_SET_TIMEOUT: |
1639 | return keyctl_set_timeout((key_serial_t) arg2, |
1640 | (unsigned) arg3); |
1641 | |
1642 | case KEYCTL_ASSUME_AUTHORITY: |
1643 | return keyctl_assume_authority((key_serial_t) arg2); |
1644 | |
1645 | case KEYCTL_GET_SECURITY: |
1646 | return keyctl_get_security((key_serial_t) arg2, |
1647 | (char __user *) arg3, |
1648 | (size_t) arg4); |
1649 | |
1650 | case KEYCTL_SESSION_TO_PARENT: |
1651 | return keyctl_session_to_parent(); |
1652 | |
1653 | case KEYCTL_REJECT: |
1654 | return keyctl_reject_key((key_serial_t) arg2, |
1655 | (unsigned) arg3, |
1656 | (unsigned) arg4, |
1657 | (key_serial_t) arg5); |
1658 | |
1659 | case KEYCTL_INSTANTIATE_IOV: |
1660 | return keyctl_instantiate_key_iov( |
1661 | (key_serial_t) arg2, |
1662 | (const struct iovec __user *) arg3, |
1663 | (unsigned) arg4, |
1664 | (key_serial_t) arg5); |
1665 | |
1666 | case KEYCTL_INVALIDATE: |
1667 | return keyctl_invalidate_key((key_serial_t) arg2); |
1668 | |
1669 | default: |
1670 | return -EOPNOTSUPP; |
1671 | } |
1672 | } |
1673 |
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v2.6.34-rc5
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