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1 | /* keyctl.c: userspace keyctl 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/keyctl.h> | |
18 | #include <linux/fs.h> | |
19 | #include <linux/capability.h> | |
20 | #include <linux/string.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/vmalloc.h> | |
23 | #include <linux/security.h> | |
24 | #include <asm/uaccess.h> | |
25 | #include "internal.h" | |
26 | ||
27 | static int key_get_type_from_user(char *type, | |
28 | const char __user *_type, | |
29 | unsigned len) | |
30 | { | |
31 | int ret; | |
32 | ||
33 | ret = strncpy_from_user(type, _type, len); | |
34 | ||
35 | if (ret < 0) | |
36 | return ret; | |
37 | ||
38 | if (ret == 0 || ret >= len) | |
39 | return -EINVAL; | |
40 | ||
41 | if (type[0] == '.') | |
42 | return -EPERM; | |
43 | ||
44 | type[len - 1] = '\0'; | |
45 | ||
46 | return 0; | |
47 | } | |
48 | ||
49 | /*****************************************************************************/ | |
50 | /* | |
51 | * extract the description of a new key from userspace and either add it as a | |
52 | * new key to the specified keyring or update a matching key in that keyring | |
53 | * - the keyring must be writable | |
54 | * - returns the new key's serial number | |
55 | * - implements add_key() | |
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 = strndup_user(_description, PAGE_SIZE); | |
79 | if (IS_ERR(description)) { | |
80 | ret = PTR_ERR(description); | |
81 | goto error; | |
82 | } | |
83 | ||
84 | /* pull the payload in if one was supplied */ | |
85 | payload = NULL; | |
86 | ||
87 | vm = false; | |
88 | if (_payload) { | |
89 | ret = -ENOMEM; | |
90 | payload = kmalloc(plen, GFP_KERNEL); | |
91 | if (!payload) { | |
92 | if (plen <= PAGE_SIZE) | |
93 | goto error2; | |
94 | vm = true; | |
95 | payload = vmalloc(plen); | |
96 | if (!payload) | |
97 | goto error2; | |
98 | } | |
99 | ||
100 | ret = -EFAULT; | |
101 | if (copy_from_user(payload, _payload, plen) != 0) | |
102 | goto error3; | |
103 | } | |
104 | ||
105 | /* find the target keyring (which must be writable) */ | |
106 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); | |
107 | if (IS_ERR(keyring_ref)) { | |
108 | ret = PTR_ERR(keyring_ref); | |
109 | goto error3; | |
110 | } | |
111 | ||
112 | /* create or update the requested key and add it to the target | |
113 | * keyring */ | |
114 | key_ref = key_create_or_update(keyring_ref, type, description, | |
115 | payload, plen, KEY_PERM_UNDEF, | |
116 | KEY_ALLOC_IN_QUOTA); | |
117 | if (!IS_ERR(key_ref)) { | |
118 | ret = key_ref_to_ptr(key_ref)->serial; | |
119 | key_ref_put(key_ref); | |
120 | } | |
121 | else { | |
122 | ret = PTR_ERR(key_ref); | |
123 | } | |
124 | ||
125 | key_ref_put(keyring_ref); | |
126 | error3: | |
127 | if (!vm) | |
128 | kfree(payload); | |
129 | else | |
130 | vfree(payload); | |
131 | error2: | |
132 | kfree(description); | |
133 | error: | |
134 | return ret; | |
135 | ||
136 | } /* end sys_add_key() */ | |
137 | ||
138 | /*****************************************************************************/ | |
139 | /* | |
140 | * search the process keyrings for a matching key | |
141 | * - nested keyrings may also be searched if they have Search permission | |
142 | * - if a key is found, it will be attached to the destination keyring if | |
143 | * there's one specified | |
144 | * - /sbin/request-key will be invoked if _callout_info is non-NULL | |
145 | * - the _callout_info string will be passed to /sbin/request-key | |
146 | * - if the _callout_info string is empty, it will be rendered as "-" | |
147 | * - implements request_key() | |
148 | */ | |
149 | SYSCALL_DEFINE4(request_key, const char __user *, _type, | |
150 | const char __user *, _description, | |
151 | const char __user *, _callout_info, | |
152 | key_serial_t, destringid) | |
153 | { | |
154 | struct key_type *ktype; | |
155 | struct key *key; | |
156 | key_ref_t dest_ref; | |
157 | size_t callout_len; | |
158 | char type[32], *description, *callout_info; | |
159 | long ret; | |
160 | ||
161 | /* pull the type into kernel space */ | |
162 | ret = key_get_type_from_user(type, _type, sizeof(type)); | |
163 | if (ret < 0) | |
164 | goto error; | |
165 | ||
166 | /* pull the description into kernel space */ | |
167 | description = strndup_user(_description, PAGE_SIZE); | |
168 | if (IS_ERR(description)) { | |
169 | ret = PTR_ERR(description); | |
170 | goto error; | |
171 | } | |
172 | ||
173 | /* pull the callout info into kernel space */ | |
174 | callout_info = NULL; | |
175 | callout_len = 0; | |
176 | if (_callout_info) { | |
177 | callout_info = strndup_user(_callout_info, PAGE_SIZE); | |
178 | if (IS_ERR(callout_info)) { | |
179 | ret = PTR_ERR(callout_info); | |
180 | goto error2; | |
181 | } | |
182 | callout_len = strlen(callout_info); | |
183 | } | |
184 | ||
185 | /* get the destination keyring if specified */ | |
186 | dest_ref = NULL; | |
187 | if (destringid) { | |
188 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, | |
189 | KEY_WRITE); | |
190 | if (IS_ERR(dest_ref)) { | |
191 | ret = PTR_ERR(dest_ref); | |
192 | goto error3; | |
193 | } | |
194 | } | |
195 | ||
196 | /* find the key type */ | |
197 | ktype = key_type_lookup(type); | |
198 | if (IS_ERR(ktype)) { | |
199 | ret = PTR_ERR(ktype); | |
200 | goto error4; | |
201 | } | |
202 | ||
203 | /* do the search */ | |
204 | key = request_key_and_link(ktype, description, callout_info, | |
205 | callout_len, NULL, key_ref_to_ptr(dest_ref), | |
206 | KEY_ALLOC_IN_QUOTA); | |
207 | if (IS_ERR(key)) { | |
208 | ret = PTR_ERR(key); | |
209 | goto error5; | |
210 | } | |
211 | ||
212 | ret = key->serial; | |
213 | ||
214 | key_put(key); | |
215 | error5: | |
216 | key_type_put(ktype); | |
217 | error4: | |
218 | key_ref_put(dest_ref); | |
219 | error3: | |
220 | kfree(callout_info); | |
221 | error2: | |
222 | kfree(description); | |
223 | error: | |
224 | return ret; | |
225 | ||
226 | } /* end sys_request_key() */ | |
227 | ||
228 | /*****************************************************************************/ | |
229 | /* | |
230 | * get the ID of the specified process keyring | |
231 | * - the keyring must have search permission to be found | |
232 | * - implements keyctl(KEYCTL_GET_KEYRING_ID) | |
233 | */ | |
234 | long keyctl_get_keyring_ID(key_serial_t id, int create) | |
235 | { | |
236 | key_ref_t key_ref; | |
237 | unsigned long lflags; | |
238 | long ret; | |
239 | ||
240 | lflags = create ? KEY_LOOKUP_CREATE : 0; | |
241 | key_ref = lookup_user_key(id, lflags, KEY_SEARCH); | |
242 | if (IS_ERR(key_ref)) { | |
243 | ret = PTR_ERR(key_ref); | |
244 | goto error; | |
245 | } | |
246 | ||
247 | ret = key_ref_to_ptr(key_ref)->serial; | |
248 | key_ref_put(key_ref); | |
249 | error: | |
250 | return ret; | |
251 | ||
252 | } /* end keyctl_get_keyring_ID() */ | |
253 | ||
254 | /*****************************************************************************/ | |
255 | /* | |
256 | * join the session keyring | |
257 | * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING) | |
258 | */ | |
259 | long keyctl_join_session_keyring(const char __user *_name) | |
260 | { | |
261 | char *name; | |
262 | long ret; | |
263 | ||
264 | /* fetch the name from userspace */ | |
265 | name = NULL; | |
266 | if (_name) { | |
267 | name = strndup_user(_name, PAGE_SIZE); | |
268 | if (IS_ERR(name)) { | |
269 | ret = PTR_ERR(name); | |
270 | goto error; | |
271 | } | |
272 | } | |
273 | ||
274 | /* join the session */ | |
275 | ret = join_session_keyring(name); | |
276 | kfree(name); | |
277 | ||
278 | error: | |
279 | return ret; | |
280 | ||
281 | } /* end keyctl_join_session_keyring() */ | |
282 | ||
283 | /*****************************************************************************/ | |
284 | /* | |
285 | * update a key's data payload | |
286 | * - the key must be writable | |
287 | * - implements keyctl(KEYCTL_UPDATE) | |
288 | */ | |
289 | long keyctl_update_key(key_serial_t id, | |
290 | const void __user *_payload, | |
291 | size_t plen) | |
292 | { | |
293 | key_ref_t key_ref; | |
294 | void *payload; | |
295 | long ret; | |
296 | ||
297 | ret = -EINVAL; | |
298 | if (plen > PAGE_SIZE) | |
299 | goto error; | |
300 | ||
301 | /* pull the payload in if one was supplied */ | |
302 | payload = NULL; | |
303 | if (_payload) { | |
304 | ret = -ENOMEM; | |
305 | payload = kmalloc(plen, GFP_KERNEL); | |
306 | if (!payload) | |
307 | goto error; | |
308 | ||
309 | ret = -EFAULT; | |
310 | if (copy_from_user(payload, _payload, plen) != 0) | |
311 | goto error2; | |
312 | } | |
313 | ||
314 | /* find the target key (which must be writable) */ | |
315 | key_ref = lookup_user_key(id, 0, KEY_WRITE); | |
316 | if (IS_ERR(key_ref)) { | |
317 | ret = PTR_ERR(key_ref); | |
318 | goto error2; | |
319 | } | |
320 | ||
321 | /* update the key */ | |
322 | ret = key_update(key_ref, payload, plen); | |
323 | ||
324 | key_ref_put(key_ref); | |
325 | error2: | |
326 | kfree(payload); | |
327 | error: | |
328 | return ret; | |
329 | ||
330 | } /* end keyctl_update_key() */ | |
331 | ||
332 | /*****************************************************************************/ | |
333 | /* | |
334 | * revoke a key | |
335 | * - the key must be writable | |
336 | * - implements keyctl(KEYCTL_REVOKE) | |
337 | */ | |
338 | long keyctl_revoke_key(key_serial_t id) | |
339 | { | |
340 | key_ref_t key_ref; | |
341 | long ret; | |
342 | ||
343 | key_ref = lookup_user_key(id, 0, KEY_WRITE); | |
344 | if (IS_ERR(key_ref)) { | |
345 | ret = PTR_ERR(key_ref); | |
346 | if (ret != -EACCES) | |
347 | goto error; | |
348 | key_ref = lookup_user_key(id, 0, KEY_SETATTR); | |
349 | if (IS_ERR(key_ref)) { | |
350 | ret = PTR_ERR(key_ref); | |
351 | goto error; | |
352 | } | |
353 | } | |
354 | ||
355 | key_revoke(key_ref_to_ptr(key_ref)); | |
356 | ret = 0; | |
357 | ||
358 | key_ref_put(key_ref); | |
359 | error: | |
360 | return ret; | |
361 | ||
362 | } /* end keyctl_revoke_key() */ | |
363 | ||
364 | /*****************************************************************************/ | |
365 | /* | |
366 | * clear the specified process keyring | |
367 | * - the keyring must be writable | |
368 | * - implements keyctl(KEYCTL_CLEAR) | |
369 | */ | |
370 | long keyctl_keyring_clear(key_serial_t ringid) | |
371 | { | |
372 | key_ref_t keyring_ref; | |
373 | long ret; | |
374 | ||
375 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); | |
376 | if (IS_ERR(keyring_ref)) { | |
377 | ret = PTR_ERR(keyring_ref); | |
378 | goto error; | |
379 | } | |
380 | ||
381 | ret = keyring_clear(key_ref_to_ptr(keyring_ref)); | |
382 | ||
383 | key_ref_put(keyring_ref); | |
384 | error: | |
385 | return ret; | |
386 | ||
387 | } /* end keyctl_keyring_clear() */ | |
388 | ||
389 | /*****************************************************************************/ | |
390 | /* | |
391 | * link a key into a keyring | |
392 | * - the keyring must be writable | |
393 | * - the key must be linkable | |
394 | * - implements keyctl(KEYCTL_LINK) | |
395 | */ | |
396 | long keyctl_keyring_link(key_serial_t id, key_serial_t ringid) | |
397 | { | |
398 | key_ref_t keyring_ref, key_ref; | |
399 | long ret; | |
400 | ||
401 | keyring_ref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); | |
402 | if (IS_ERR(keyring_ref)) { | |
403 | ret = PTR_ERR(keyring_ref); | |
404 | goto error; | |
405 | } | |
406 | ||
407 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE, KEY_LINK); | |
408 | if (IS_ERR(key_ref)) { | |
409 | ret = PTR_ERR(key_ref); | |
410 | goto error2; | |
411 | } | |
412 | ||
413 | ret = key_link(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); | |
414 | ||
415 | key_ref_put(key_ref); | |
416 | error2: | |
417 | key_ref_put(keyring_ref); | |
418 | error: | |
419 | return ret; | |
420 | ||
421 | } /* end keyctl_keyring_link() */ | |
422 | ||
423 | /*****************************************************************************/ | |
424 | /* | |
425 | * unlink the first attachment of a key from a keyring | |
426 | * - the keyring must be writable | |
427 | * - we don't need any permissions on the key | |
428 | * - implements keyctl(KEYCTL_UNLINK) | |
429 | */ | |
430 | long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid) | |
431 | { | |
432 | key_ref_t keyring_ref, key_ref; | |
433 | long ret; | |
434 | ||
435 | keyring_ref = lookup_user_key(ringid, 0, KEY_WRITE); | |
436 | if (IS_ERR(keyring_ref)) { | |
437 | ret = PTR_ERR(keyring_ref); | |
438 | goto error; | |
439 | } | |
440 | ||
441 | key_ref = lookup_user_key(id, KEY_LOOKUP_FOR_UNLINK, 0); | |
442 | if (IS_ERR(key_ref)) { | |
443 | ret = PTR_ERR(key_ref); | |
444 | goto error2; | |
445 | } | |
446 | ||
447 | ret = key_unlink(key_ref_to_ptr(keyring_ref), key_ref_to_ptr(key_ref)); | |
448 | ||
449 | key_ref_put(key_ref); | |
450 | error2: | |
451 | key_ref_put(keyring_ref); | |
452 | error: | |
453 | return ret; | |
454 | ||
455 | } /* end keyctl_keyring_unlink() */ | |
456 | ||
457 | /*****************************************************************************/ | |
458 | /* | |
459 | * describe a user key | |
460 | * - the key must have view permission | |
461 | * - if there's a buffer, we place up to buflen bytes of data into it | |
462 | * - unless there's an error, we return the amount of description available, | |
463 | * irrespective of how much we may have copied | |
464 | * - the description is formatted thus: | |
465 | * type;uid;gid;perm;description<NUL> | |
466 | * - implements keyctl(KEYCTL_DESCRIBE) | |
467 | */ | |
468 | long keyctl_describe_key(key_serial_t keyid, | |
469 | char __user *buffer, | |
470 | size_t buflen) | |
471 | { | |
472 | struct key *key, *instkey; | |
473 | key_ref_t key_ref; | |
474 | char *tmpbuf; | |
475 | long ret; | |
476 | ||
477 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); | |
478 | if (IS_ERR(key_ref)) { | |
479 | /* viewing a key under construction is permitted if we have the | |
480 | * authorisation token handy */ | |
481 | if (PTR_ERR(key_ref) == -EACCES) { | |
482 | instkey = key_get_instantiation_authkey(keyid); | |
483 | if (!IS_ERR(instkey)) { | |
484 | key_put(instkey); | |
485 | key_ref = lookup_user_key(keyid, | |
486 | KEY_LOOKUP_PARTIAL, | |
487 | 0); | |
488 | if (!IS_ERR(key_ref)) | |
489 | goto okay; | |
490 | } | |
491 | } | |
492 | ||
493 | ret = PTR_ERR(key_ref); | |
494 | goto error; | |
495 | } | |
496 | ||
497 | okay: | |
498 | /* calculate how much description we're going to return */ | |
499 | ret = -ENOMEM; | |
500 | tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL); | |
501 | if (!tmpbuf) | |
502 | goto error2; | |
503 | ||
504 | key = key_ref_to_ptr(key_ref); | |
505 | ||
506 | ret = snprintf(tmpbuf, PAGE_SIZE - 1, | |
507 | "%s;%d;%d;%08x;%s", | |
508 | key->type->name, | |
509 | key->uid, | |
510 | key->gid, | |
511 | key->perm, | |
512 | key->description ?: ""); | |
513 | ||
514 | /* include a NUL char at the end of the data */ | |
515 | if (ret > PAGE_SIZE - 1) | |
516 | ret = PAGE_SIZE - 1; | |
517 | tmpbuf[ret] = 0; | |
518 | ret++; | |
519 | ||
520 | /* consider returning the data */ | |
521 | if (buffer && buflen > 0) { | |
522 | if (buflen > ret) | |
523 | buflen = ret; | |
524 | ||
525 | if (copy_to_user(buffer, tmpbuf, buflen) != 0) | |
526 | ret = -EFAULT; | |
527 | } | |
528 | ||
529 | kfree(tmpbuf); | |
530 | error2: | |
531 | key_ref_put(key_ref); | |
532 | error: | |
533 | return ret; | |
534 | ||
535 | } /* end keyctl_describe_key() */ | |
536 | ||
537 | /*****************************************************************************/ | |
538 | /* | |
539 | * search the specified keyring for a matching key | |
540 | * - the start keyring must be searchable | |
541 | * - nested keyrings may also be searched if they are searchable | |
542 | * - only keys with search permission may be found | |
543 | * - if a key is found, it will be attached to the destination keyring if | |
544 | * there's one specified | |
545 | * - implements keyctl(KEYCTL_SEARCH) | |
546 | */ | |
547 | long keyctl_keyring_search(key_serial_t ringid, | |
548 | const char __user *_type, | |
549 | const char __user *_description, | |
550 | key_serial_t destringid) | |
551 | { | |
552 | struct key_type *ktype; | |
553 | key_ref_t keyring_ref, key_ref, dest_ref; | |
554 | char type[32], *description; | |
555 | long ret; | |
556 | ||
557 | /* pull the type and description into kernel space */ | |
558 | ret = key_get_type_from_user(type, _type, sizeof(type)); | |
559 | if (ret < 0) | |
560 | goto error; | |
561 | ||
562 | description = strndup_user(_description, PAGE_SIZE); | |
563 | if (IS_ERR(description)) { | |
564 | ret = PTR_ERR(description); | |
565 | goto error; | |
566 | } | |
567 | ||
568 | /* get the keyring at which to begin the search */ | |
569 | keyring_ref = lookup_user_key(ringid, 0, KEY_SEARCH); | |
570 | if (IS_ERR(keyring_ref)) { | |
571 | ret = PTR_ERR(keyring_ref); | |
572 | goto error2; | |
573 | } | |
574 | ||
575 | /* get the destination keyring if specified */ | |
576 | dest_ref = NULL; | |
577 | if (destringid) { | |
578 | dest_ref = lookup_user_key(destringid, KEY_LOOKUP_CREATE, | |
579 | KEY_WRITE); | |
580 | if (IS_ERR(dest_ref)) { | |
581 | ret = PTR_ERR(dest_ref); | |
582 | goto error3; | |
583 | } | |
584 | } | |
585 | ||
586 | /* find the key type */ | |
587 | ktype = key_type_lookup(type); | |
588 | if (IS_ERR(ktype)) { | |
589 | ret = PTR_ERR(ktype); | |
590 | goto error4; | |
591 | } | |
592 | ||
593 | /* do the search */ | |
594 | key_ref = keyring_search(keyring_ref, ktype, description); | |
595 | if (IS_ERR(key_ref)) { | |
596 | ret = PTR_ERR(key_ref); | |
597 | ||
598 | /* treat lack or presence of a negative key the same */ | |
599 | if (ret == -EAGAIN) | |
600 | ret = -ENOKEY; | |
601 | goto error5; | |
602 | } | |
603 | ||
604 | /* link the resulting key to the destination keyring if we can */ | |
605 | if (dest_ref) { | |
606 | ret = key_permission(key_ref, KEY_LINK); | |
607 | if (ret < 0) | |
608 | goto error6; | |
609 | ||
610 | ret = key_link(key_ref_to_ptr(dest_ref), key_ref_to_ptr(key_ref)); | |
611 | if (ret < 0) | |
612 | goto error6; | |
613 | } | |
614 | ||
615 | ret = key_ref_to_ptr(key_ref)->serial; | |
616 | ||
617 | error6: | |
618 | key_ref_put(key_ref); | |
619 | error5: | |
620 | key_type_put(ktype); | |
621 | error4: | |
622 | key_ref_put(dest_ref); | |
623 | error3: | |
624 | key_ref_put(keyring_ref); | |
625 | error2: | |
626 | kfree(description); | |
627 | error: | |
628 | return ret; | |
629 | ||
630 | } /* end keyctl_keyring_search() */ | |
631 | ||
632 | /*****************************************************************************/ | |
633 | /* | |
634 | * read a user key's payload | |
635 | * - the keyring must be readable or the key must be searchable from the | |
636 | * process's keyrings | |
637 | * - if there's a buffer, we place up to buflen bytes of data into it | |
638 | * - unless there's an error, we return the amount of data in the key, | |
639 | * irrespective of how much we may have copied | |
640 | * - implements keyctl(KEYCTL_READ) | |
641 | */ | |
642 | long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen) | |
643 | { | |
644 | struct key *key; | |
645 | key_ref_t key_ref; | |
646 | long ret; | |
647 | ||
648 | /* find the key first */ | |
649 | key_ref = lookup_user_key(keyid, 0, 0); | |
650 | if (IS_ERR(key_ref)) { | |
651 | ret = -ENOKEY; | |
652 | goto error; | |
653 | } | |
654 | ||
655 | key = key_ref_to_ptr(key_ref); | |
656 | ||
657 | /* see if we can read it directly */ | |
658 | ret = key_permission(key_ref, KEY_READ); | |
659 | if (ret == 0) | |
660 | goto can_read_key; | |
661 | if (ret != -EACCES) | |
662 | goto error; | |
663 | ||
664 | /* we can't; see if it's searchable from this process's keyrings | |
665 | * - we automatically take account of the fact that it may be | |
666 | * dangling off an instantiation key | |
667 | */ | |
668 | if (!is_key_possessed(key_ref)) { | |
669 | ret = -EACCES; | |
670 | goto error2; | |
671 | } | |
672 | ||
673 | /* the key is probably readable - now try to read it */ | |
674 | can_read_key: | |
675 | ret = key_validate(key); | |
676 | if (ret == 0) { | |
677 | ret = -EOPNOTSUPP; | |
678 | if (key->type->read) { | |
679 | /* read the data with the semaphore held (since we | |
680 | * might sleep) */ | |
681 | down_read(&key->sem); | |
682 | ret = key->type->read(key, buffer, buflen); | |
683 | up_read(&key->sem); | |
684 | } | |
685 | } | |
686 | ||
687 | error2: | |
688 | key_put(key); | |
689 | error: | |
690 | return ret; | |
691 | ||
692 | } /* end keyctl_read_key() */ | |
693 | ||
694 | /*****************************************************************************/ | |
695 | /* | |
696 | * change the ownership of a key | |
697 | * - the keyring owned by the changer | |
698 | * - if the uid or gid is -1, then that parameter is not changed | |
699 | * - implements keyctl(KEYCTL_CHOWN) | |
700 | */ | |
701 | long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid) | |
702 | { | |
703 | struct key_user *newowner, *zapowner = NULL; | |
704 | struct key *key; | |
705 | key_ref_t key_ref; | |
706 | long ret; | |
707 | ||
708 | ret = 0; | |
709 | if (uid == (uid_t) -1 && gid == (gid_t) -1) | |
710 | goto error; | |
711 | ||
712 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, | |
713 | KEY_SETATTR); | |
714 | if (IS_ERR(key_ref)) { | |
715 | ret = PTR_ERR(key_ref); | |
716 | goto error; | |
717 | } | |
718 | ||
719 | key = key_ref_to_ptr(key_ref); | |
720 | ||
721 | /* make the changes with the locks held to prevent chown/chown races */ | |
722 | ret = -EACCES; | |
723 | down_write(&key->sem); | |
724 | ||
725 | if (!capable(CAP_SYS_ADMIN)) { | |
726 | /* only the sysadmin can chown a key to some other UID */ | |
727 | if (uid != (uid_t) -1 && key->uid != uid) | |
728 | goto error_put; | |
729 | ||
730 | /* only the sysadmin can set the key's GID to a group other | |
731 | * than one of those that the current process subscribes to */ | |
732 | if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid)) | |
733 | goto error_put; | |
734 | } | |
735 | ||
736 | /* change the UID */ | |
737 | if (uid != (uid_t) -1 && uid != key->uid) { | |
738 | ret = -ENOMEM; | |
739 | newowner = key_user_lookup(uid, current_user_ns()); | |
740 | if (!newowner) | |
741 | goto error_put; | |
742 | ||
743 | /* transfer the quota burden to the new user */ | |
744 | if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) { | |
745 | unsigned maxkeys = (uid == 0) ? | |
746 | key_quota_root_maxkeys : key_quota_maxkeys; | |
747 | unsigned maxbytes = (uid == 0) ? | |
748 | key_quota_root_maxbytes : key_quota_maxbytes; | |
749 | ||
750 | spin_lock(&newowner->lock); | |
751 | if (newowner->qnkeys + 1 >= maxkeys || | |
752 | newowner->qnbytes + key->quotalen >= maxbytes || | |
753 | newowner->qnbytes + key->quotalen < | |
754 | newowner->qnbytes) | |
755 | goto quota_overrun; | |
756 | ||
757 | newowner->qnkeys++; | |
758 | newowner->qnbytes += key->quotalen; | |
759 | spin_unlock(&newowner->lock); | |
760 | ||
761 | spin_lock(&key->user->lock); | |
762 | key->user->qnkeys--; | |
763 | key->user->qnbytes -= key->quotalen; | |
764 | spin_unlock(&key->user->lock); | |
765 | } | |
766 | ||
767 | atomic_dec(&key->user->nkeys); | |
768 | atomic_inc(&newowner->nkeys); | |
769 | ||
770 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) { | |
771 | atomic_dec(&key->user->nikeys); | |
772 | atomic_inc(&newowner->nikeys); | |
773 | } | |
774 | ||
775 | zapowner = key->user; | |
776 | key->user = newowner; | |
777 | key->uid = uid; | |
778 | } | |
779 | ||
780 | /* change the GID */ | |
781 | if (gid != (gid_t) -1) | |
782 | key->gid = gid; | |
783 | ||
784 | ret = 0; | |
785 | ||
786 | error_put: | |
787 | up_write(&key->sem); | |
788 | key_put(key); | |
789 | if (zapowner) | |
790 | key_user_put(zapowner); | |
791 | error: | |
792 | return ret; | |
793 | ||
794 | quota_overrun: | |
795 | spin_unlock(&newowner->lock); | |
796 | zapowner = newowner; | |
797 | ret = -EDQUOT; | |
798 | goto error_put; | |
799 | ||
800 | } /* end keyctl_chown_key() */ | |
801 | ||
802 | /*****************************************************************************/ | |
803 | /* | |
804 | * change the permission mask on a key | |
805 | * - the keyring owned by the changer | |
806 | * - implements keyctl(KEYCTL_SETPERM) | |
807 | */ | |
808 | long keyctl_setperm_key(key_serial_t id, key_perm_t perm) | |
809 | { | |
810 | struct key *key; | |
811 | key_ref_t key_ref; | |
812 | long ret; | |
813 | ||
814 | ret = -EINVAL; | |
815 | if (perm & ~(KEY_POS_ALL | KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL)) | |
816 | goto error; | |
817 | ||
818 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, | |
819 | KEY_SETATTR); | |
820 | if (IS_ERR(key_ref)) { | |
821 | ret = PTR_ERR(key_ref); | |
822 | goto error; | |
823 | } | |
824 | ||
825 | key = key_ref_to_ptr(key_ref); | |
826 | ||
827 | /* make the changes with the locks held to prevent chown/chmod races */ | |
828 | ret = -EACCES; | |
829 | down_write(&key->sem); | |
830 | ||
831 | /* if we're not the sysadmin, we can only change a key that we own */ | |
832 | if (capable(CAP_SYS_ADMIN) || key->uid == current_fsuid()) { | |
833 | key->perm = perm; | |
834 | ret = 0; | |
835 | } | |
836 | ||
837 | up_write(&key->sem); | |
838 | key_put(key); | |
839 | error: | |
840 | return ret; | |
841 | ||
842 | } /* end keyctl_setperm_key() */ | |
843 | ||
844 | /* | |
845 | * get the destination keyring for instantiation | |
846 | */ | |
847 | static long get_instantiation_keyring(key_serial_t ringid, | |
848 | struct request_key_auth *rka, | |
849 | struct key **_dest_keyring) | |
850 | { | |
851 | key_ref_t dkref; | |
852 | ||
853 | *_dest_keyring = NULL; | |
854 | ||
855 | /* just return a NULL pointer if we weren't asked to make a link */ | |
856 | if (ringid == 0) | |
857 | return 0; | |
858 | ||
859 | /* if a specific keyring is nominated by ID, then use that */ | |
860 | if (ringid > 0) { | |
861 | dkref = lookup_user_key(ringid, KEY_LOOKUP_CREATE, KEY_WRITE); | |
862 | if (IS_ERR(dkref)) | |
863 | return PTR_ERR(dkref); | |
864 | *_dest_keyring = key_ref_to_ptr(dkref); | |
865 | return 0; | |
866 | } | |
867 | ||
868 | if (ringid == KEY_SPEC_REQKEY_AUTH_KEY) | |
869 | return -EINVAL; | |
870 | ||
871 | /* otherwise specify the destination keyring recorded in the | |
872 | * authorisation key (any KEY_SPEC_*_KEYRING) */ | |
873 | if (ringid >= KEY_SPEC_REQUESTOR_KEYRING) { | |
874 | *_dest_keyring = key_get(rka->dest_keyring); | |
875 | return 0; | |
876 | } | |
877 | ||
878 | return -ENOKEY; | |
879 | } | |
880 | ||
881 | /* | |
882 | * change the request_key authorisation key on the current process | |
883 | */ | |
884 | static int keyctl_change_reqkey_auth(struct key *key) | |
885 | { | |
886 | struct cred *new; | |
887 | ||
888 | new = prepare_creds(); | |
889 | if (!new) | |
890 | return -ENOMEM; | |
891 | ||
892 | key_put(new->request_key_auth); | |
893 | new->request_key_auth = key_get(key); | |
894 | ||
895 | return commit_creds(new); | |
896 | } | |
897 | ||
898 | /*****************************************************************************/ | |
899 | /* | |
900 | * instantiate the key with the specified payload, and, if one is given, link | |
901 | * the key into the keyring | |
902 | */ | |
903 | long keyctl_instantiate_key(key_serial_t id, | |
904 | const void __user *_payload, | |
905 | size_t plen, | |
906 | key_serial_t ringid) | |
907 | { | |
908 | const struct cred *cred = current_cred(); | |
909 | struct request_key_auth *rka; | |
910 | struct key *instkey, *dest_keyring; | |
911 | void *payload; | |
912 | long ret; | |
913 | bool vm = false; | |
914 | ||
915 | kenter("%d,,%zu,%d", id, plen, ringid); | |
916 | ||
917 | ret = -EINVAL; | |
918 | if (plen > 1024 * 1024 - 1) | |
919 | goto error; | |
920 | ||
921 | /* the appropriate instantiation authorisation key must have been | |
922 | * assumed before calling this */ | |
923 | ret = -EPERM; | |
924 | instkey = cred->request_key_auth; | |
925 | if (!instkey) | |
926 | goto error; | |
927 | ||
928 | rka = instkey->payload.data; | |
929 | if (rka->target_key->serial != id) | |
930 | goto error; | |
931 | ||
932 | /* pull the payload in if one was supplied */ | |
933 | payload = NULL; | |
934 | ||
935 | if (_payload) { | |
936 | ret = -ENOMEM; | |
937 | payload = kmalloc(plen, GFP_KERNEL); | |
938 | if (!payload) { | |
939 | if (plen <= PAGE_SIZE) | |
940 | goto error; | |
941 | vm = true; | |
942 | payload = vmalloc(plen); | |
943 | if (!payload) | |
944 | goto error; | |
945 | } | |
946 | ||
947 | ret = -EFAULT; | |
948 | if (copy_from_user(payload, _payload, plen) != 0) | |
949 | goto error2; | |
950 | } | |
951 | ||
952 | /* find the destination keyring amongst those belonging to the | |
953 | * requesting task */ | |
954 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); | |
955 | if (ret < 0) | |
956 | goto error2; | |
957 | ||
958 | /* instantiate the key and link it into a keyring */ | |
959 | ret = key_instantiate_and_link(rka->target_key, payload, plen, | |
960 | dest_keyring, instkey); | |
961 | ||
962 | key_put(dest_keyring); | |
963 | ||
964 | /* discard the assumed authority if it's just been disabled by | |
965 | * instantiation of the key */ | |
966 | if (ret == 0) | |
967 | keyctl_change_reqkey_auth(NULL); | |
968 | ||
969 | error2: | |
970 | if (!vm) | |
971 | kfree(payload); | |
972 | else | |
973 | vfree(payload); | |
974 | error: | |
975 | return ret; | |
976 | ||
977 | } /* end keyctl_instantiate_key() */ | |
978 | ||
979 | /*****************************************************************************/ | |
980 | /* | |
981 | * negatively instantiate the key with the given timeout (in seconds), and, if | |
982 | * one is given, link the key into the keyring | |
983 | */ | |
984 | long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) | |
985 | { | |
986 | const struct cred *cred = current_cred(); | |
987 | struct request_key_auth *rka; | |
988 | struct key *instkey, *dest_keyring; | |
989 | long ret; | |
990 | ||
991 | kenter("%d,%u,%d", id, timeout, ringid); | |
992 | ||
993 | /* the appropriate instantiation authorisation key must have been | |
994 | * assumed before calling this */ | |
995 | ret = -EPERM; | |
996 | instkey = cred->request_key_auth; | |
997 | if (!instkey) | |
998 | goto error; | |
999 | ||
1000 | rka = instkey->payload.data; | |
1001 | if (rka->target_key->serial != id) | |
1002 | goto error; | |
1003 | ||
1004 | /* find the destination keyring if present (which must also be | |
1005 | * writable) */ | |
1006 | ret = get_instantiation_keyring(ringid, rka, &dest_keyring); | |
1007 | if (ret < 0) | |
1008 | goto error; | |
1009 | ||
1010 | /* instantiate the key and link it into a keyring */ | |
1011 | ret = key_negate_and_link(rka->target_key, timeout, | |
1012 | dest_keyring, instkey); | |
1013 | ||
1014 | key_put(dest_keyring); | |
1015 | ||
1016 | /* discard the assumed authority if it's just been disabled by | |
1017 | * instantiation of the key */ | |
1018 | if (ret == 0) | |
1019 | keyctl_change_reqkey_auth(NULL); | |
1020 | ||
1021 | error: | |
1022 | return ret; | |
1023 | ||
1024 | } /* end keyctl_negate_key() */ | |
1025 | ||
1026 | /*****************************************************************************/ | |
1027 | /* | |
1028 | * set the default keyring in which request_key() will cache keys | |
1029 | * - return the old setting | |
1030 | */ | |
1031 | long keyctl_set_reqkey_keyring(int reqkey_defl) | |
1032 | { | |
1033 | struct cred *new; | |
1034 | int ret, old_setting; | |
1035 | ||
1036 | old_setting = current_cred_xxx(jit_keyring); | |
1037 | ||
1038 | if (reqkey_defl == KEY_REQKEY_DEFL_NO_CHANGE) | |
1039 | return old_setting; | |
1040 | ||
1041 | new = prepare_creds(); | |
1042 | if (!new) | |
1043 | return -ENOMEM; | |
1044 | ||
1045 | switch (reqkey_defl) { | |
1046 | case KEY_REQKEY_DEFL_THREAD_KEYRING: | |
1047 | ret = install_thread_keyring_to_cred(new); | |
1048 | if (ret < 0) | |
1049 | goto error; | |
1050 | goto set; | |
1051 | ||
1052 | case KEY_REQKEY_DEFL_PROCESS_KEYRING: | |
1053 | ret = install_process_keyring_to_cred(new); | |
1054 | if (ret < 0) { | |
1055 | if (ret != -EEXIST) | |
1056 | goto error; | |
1057 | ret = 0; | |
1058 | } | |
1059 | goto set; | |
1060 | ||
1061 | case KEY_REQKEY_DEFL_DEFAULT: | |
1062 | case KEY_REQKEY_DEFL_SESSION_KEYRING: | |
1063 | case KEY_REQKEY_DEFL_USER_KEYRING: | |
1064 | case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: | |
1065 | case KEY_REQKEY_DEFL_REQUESTOR_KEYRING: | |
1066 | goto set; | |
1067 | ||
1068 | case KEY_REQKEY_DEFL_NO_CHANGE: | |
1069 | case KEY_REQKEY_DEFL_GROUP_KEYRING: | |
1070 | default: | |
1071 | ret = -EINVAL; | |
1072 | goto error; | |
1073 | } | |
1074 | ||
1075 | set: | |
1076 | new->jit_keyring = reqkey_defl; | |
1077 | commit_creds(new); | |
1078 | return old_setting; | |
1079 | error: | |
1080 | abort_creds(new); | |
1081 | return ret; | |
1082 | ||
1083 | } /* end keyctl_set_reqkey_keyring() */ | |
1084 | ||
1085 | /*****************************************************************************/ | |
1086 | /* | |
1087 | * set or clear the timeout for a key | |
1088 | */ | |
1089 | long keyctl_set_timeout(key_serial_t id, unsigned timeout) | |
1090 | { | |
1091 | struct timespec now; | |
1092 | struct key *key, *instkey; | |
1093 | key_ref_t key_ref; | |
1094 | time_t expiry; | |
1095 | long ret; | |
1096 | ||
1097 | key_ref = lookup_user_key(id, KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL, | |
1098 | KEY_SETATTR); | |
1099 | if (IS_ERR(key_ref)) { | |
1100 | /* setting the timeout on a key under construction is permitted | |
1101 | * if we have the authorisation token handy */ | |
1102 | if (PTR_ERR(key_ref) == -EACCES) { | |
1103 | instkey = key_get_instantiation_authkey(id); | |
1104 | if (!IS_ERR(instkey)) { | |
1105 | key_put(instkey); | |
1106 | key_ref = lookup_user_key(id, | |
1107 | KEY_LOOKUP_PARTIAL, | |
1108 | 0); | |
1109 | if (!IS_ERR(key_ref)) | |
1110 | goto okay; | |
1111 | } | |
1112 | } | |
1113 | ||
1114 | ret = PTR_ERR(key_ref); | |
1115 | goto error; | |
1116 | } | |
1117 | ||
1118 | okay: | |
1119 | key = key_ref_to_ptr(key_ref); | |
1120 | ||
1121 | /* make the changes with the locks held to prevent races */ | |
1122 | down_write(&key->sem); | |
1123 | ||
1124 | expiry = 0; | |
1125 | if (timeout > 0) { | |
1126 | now = current_kernel_time(); | |
1127 | expiry = now.tv_sec + timeout; | |
1128 | } | |
1129 | ||
1130 | key->expiry = expiry; | |
1131 | key_schedule_gc(key->expiry + key_gc_delay); | |
1132 | ||
1133 | up_write(&key->sem); | |
1134 | key_put(key); | |
1135 | ||
1136 | ret = 0; | |
1137 | error: | |
1138 | return ret; | |
1139 | ||
1140 | } /* end keyctl_set_timeout() */ | |
1141 | ||
1142 | /*****************************************************************************/ | |
1143 | /* | |
1144 | * assume the authority to instantiate the specified key | |
1145 | */ | |
1146 | long keyctl_assume_authority(key_serial_t id) | |
1147 | { | |
1148 | struct key *authkey; | |
1149 | long ret; | |
1150 | ||
1151 | /* special key IDs aren't permitted */ | |
1152 | ret = -EINVAL; | |
1153 | if (id < 0) | |
1154 | goto error; | |
1155 | ||
1156 | /* we divest ourselves of authority if given an ID of 0 */ | |
1157 | if (id == 0) { | |
1158 | ret = keyctl_change_reqkey_auth(NULL); | |
1159 | goto error; | |
1160 | } | |
1161 | ||
1162 | /* attempt to assume the authority temporarily granted to us whilst we | |
1163 | * instantiate the specified key | |
1164 | * - the authorisation key must be in the current task's keyrings | |
1165 | * somewhere | |
1166 | */ | |
1167 | authkey = key_get_instantiation_authkey(id); | |
1168 | if (IS_ERR(authkey)) { | |
1169 | ret = PTR_ERR(authkey); | |
1170 | goto error; | |
1171 | } | |
1172 | ||
1173 | ret = keyctl_change_reqkey_auth(authkey); | |
1174 | if (ret < 0) | |
1175 | goto error; | |
1176 | key_put(authkey); | |
1177 | ||
1178 | ret = authkey->serial; | |
1179 | error: | |
1180 | return ret; | |
1181 | ||
1182 | } /* end keyctl_assume_authority() */ | |
1183 | ||
1184 | /* | |
1185 | * get the security label of a key | |
1186 | * - the key must grant us view permission | |
1187 | * - if there's a buffer, we place up to buflen bytes of data into it | |
1188 | * - unless there's an error, we return the amount of information available, | |
1189 | * irrespective of how much we may have copied (including the terminal NUL) | |
1190 | * - implements keyctl(KEYCTL_GET_SECURITY) | |
1191 | */ | |
1192 | long keyctl_get_security(key_serial_t keyid, | |
1193 | char __user *buffer, | |
1194 | size_t buflen) | |
1195 | { | |
1196 | struct key *key, *instkey; | |
1197 | key_ref_t key_ref; | |
1198 | char *context; | |
1199 | long ret; | |
1200 | ||
1201 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, KEY_VIEW); | |
1202 | if (IS_ERR(key_ref)) { | |
1203 | if (PTR_ERR(key_ref) != -EACCES) | |
1204 | return PTR_ERR(key_ref); | |
1205 | ||
1206 | /* viewing a key under construction is also permitted if we | |
1207 | * have the authorisation token handy */ | |
1208 | instkey = key_get_instantiation_authkey(keyid); | |
1209 | if (IS_ERR(instkey)) | |
1210 | return PTR_ERR(instkey); | |
1211 | key_put(instkey); | |
1212 | ||
1213 | key_ref = lookup_user_key(keyid, KEY_LOOKUP_PARTIAL, 0); | |
1214 | if (IS_ERR(key_ref)) | |
1215 | return PTR_ERR(key_ref); | |
1216 | } | |
1217 | ||
1218 | key = key_ref_to_ptr(key_ref); | |
1219 | ret = security_key_getsecurity(key, &context); | |
1220 | if (ret == 0) { | |
1221 | /* if no information was returned, give userspace an empty | |
1222 | * string */ | |
1223 | ret = 1; | |
1224 | if (buffer && buflen > 0 && | |
1225 | copy_to_user(buffer, "", 1) != 0) | |
1226 | ret = -EFAULT; | |
1227 | } else if (ret > 0) { | |
1228 | /* return as much data as there's room for */ | |
1229 | if (buffer && buflen > 0) { | |
1230 | if (buflen > ret) | |
1231 | buflen = ret; | |
1232 | ||
1233 | if (copy_to_user(buffer, context, buflen) != 0) | |
1234 | ret = -EFAULT; | |
1235 | } | |
1236 | ||
1237 | kfree(context); | |
1238 | } | |
1239 | ||
1240 | key_ref_put(key_ref); | |
1241 | return ret; | |
1242 | } | |
1243 | ||
1244 | /* | |
1245 | * attempt to install the calling process's session keyring on the process's | |
1246 | * parent process | |
1247 | * - the keyring must exist and must grant us LINK permission | |
1248 | * - implements keyctl(KEYCTL_SESSION_TO_PARENT) | |
1249 | */ | |
1250 | long keyctl_session_to_parent(void) | |
1251 | { | |
1252 | #ifdef TIF_NOTIFY_RESUME | |
1253 | struct task_struct *me, *parent; | |
1254 | const struct cred *mycred, *pcred; | |
1255 | struct cred *cred, *oldcred; | |
1256 | key_ref_t keyring_r; | |
1257 | int ret; | |
1258 | ||
1259 | keyring_r = lookup_user_key(KEY_SPEC_SESSION_KEYRING, 0, KEY_LINK); | |
1260 | if (IS_ERR(keyring_r)) | |
1261 | return PTR_ERR(keyring_r); | |
1262 | ||
1263 | /* our parent is going to need a new cred struct, a new tgcred struct | |
1264 | * and new security data, so we allocate them here to prevent ENOMEM in | |
1265 | * our parent */ | |
1266 | ret = -ENOMEM; | |
1267 | cred = cred_alloc_blank(); | |
1268 | if (!cred) | |
1269 | goto error_keyring; | |
1270 | ||
1271 | cred->tgcred->session_keyring = key_ref_to_ptr(keyring_r); | |
1272 | keyring_r = NULL; | |
1273 | ||
1274 | me = current; | |
1275 | rcu_read_lock(); | |
1276 | write_lock_irq(&tasklist_lock); | |
1277 | ||
1278 | parent = me->real_parent; | |
1279 | ret = -EPERM; | |
1280 | ||
1281 | /* the parent mustn't be init and mustn't be a kernel thread */ | |
1282 | if (parent->pid <= 1 || !parent->mm) | |
1283 | goto not_permitted; | |
1284 | ||
1285 | /* the parent must be single threaded */ | |
1286 | if (!thread_group_empty(parent)) | |
1287 | goto not_permitted; | |
1288 | ||
1289 | /* the parent and the child must have different session keyrings or | |
1290 | * there's no point */ | |
1291 | mycred = current_cred(); | |
1292 | pcred = __task_cred(parent); | |
1293 | if (mycred == pcred || | |
1294 | mycred->tgcred->session_keyring == pcred->tgcred->session_keyring) | |
1295 | goto already_same; | |
1296 | ||
1297 | /* the parent must have the same effective ownership and mustn't be | |
1298 | * SUID/SGID */ | |
1299 | if (pcred->uid != mycred->euid || | |
1300 | pcred->euid != mycred->euid || | |
1301 | pcred->suid != mycred->euid || | |
1302 | pcred->gid != mycred->egid || | |
1303 | pcred->egid != mycred->egid || | |
1304 | pcred->sgid != mycred->egid) | |
1305 | goto not_permitted; | |
1306 | ||
1307 | /* the keyrings must have the same UID */ | |
1308 | if ((pcred->tgcred->session_keyring && | |
1309 | pcred->tgcred->session_keyring->uid != mycred->euid) || | |
1310 | mycred->tgcred->session_keyring->uid != mycred->euid) | |
1311 | goto not_permitted; | |
1312 | ||
1313 | /* if there's an already pending keyring replacement, then we replace | |
1314 | * that */ | |
1315 | oldcred = parent->replacement_session_keyring; | |
1316 | ||
1317 | /* the replacement session keyring is applied just prior to userspace | |
1318 | * restarting */ | |
1319 | parent->replacement_session_keyring = cred; | |
1320 | cred = NULL; | |
1321 | set_ti_thread_flag(task_thread_info(parent), TIF_NOTIFY_RESUME); | |
1322 | ||
1323 | write_unlock_irq(&tasklist_lock); | |
1324 | rcu_read_unlock(); | |
1325 | if (oldcred) | |
1326 | put_cred(oldcred); | |
1327 | return 0; | |
1328 | ||
1329 | already_same: | |
1330 | ret = 0; | |
1331 | not_permitted: | |
1332 | write_unlock_irq(&tasklist_lock); | |
1333 | rcu_read_unlock(); | |
1334 | put_cred(cred); | |
1335 | return ret; | |
1336 | ||
1337 | error_keyring: | |
1338 | key_ref_put(keyring_r); | |
1339 | return ret; | |
1340 | ||
1341 | #else /* !TIF_NOTIFY_RESUME */ | |
1342 | /* | |
1343 | * To be removed when TIF_NOTIFY_RESUME has been implemented on | |
1344 | * m68k/xtensa | |
1345 | */ | |
1346 | #warning TIF_NOTIFY_RESUME not implemented | |
1347 | return -EOPNOTSUPP; | |
1348 | #endif /* !TIF_NOTIFY_RESUME */ | |
1349 | } | |
1350 | ||
1351 | /*****************************************************************************/ | |
1352 | /* | |
1353 | * the key control system call | |
1354 | */ | |
1355 | SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, | |
1356 | unsigned long, arg4, unsigned long, arg5) | |
1357 | { | |
1358 | switch (option) { | |
1359 | case KEYCTL_GET_KEYRING_ID: | |
1360 | return keyctl_get_keyring_ID((key_serial_t) arg2, | |
1361 | (int) arg3); | |
1362 | ||
1363 | case KEYCTL_JOIN_SESSION_KEYRING: | |
1364 | return keyctl_join_session_keyring((const char __user *) arg2); | |
1365 | ||
1366 | case KEYCTL_UPDATE: | |
1367 | return keyctl_update_key((key_serial_t) arg2, | |
1368 | (const void __user *) arg3, | |
1369 | (size_t) arg4); | |
1370 | ||
1371 | case KEYCTL_REVOKE: | |
1372 | return keyctl_revoke_key((key_serial_t) arg2); | |
1373 | ||
1374 | case KEYCTL_DESCRIBE: | |
1375 | return keyctl_describe_key((key_serial_t) arg2, | |
1376 | (char __user *) arg3, | |
1377 | (unsigned) arg4); | |
1378 | ||
1379 | case KEYCTL_CLEAR: | |
1380 | return keyctl_keyring_clear((key_serial_t) arg2); | |
1381 | ||
1382 | case KEYCTL_LINK: | |
1383 | return keyctl_keyring_link((key_serial_t) arg2, | |
1384 | (key_serial_t) arg3); | |
1385 | ||
1386 | case KEYCTL_UNLINK: | |
1387 | return keyctl_keyring_unlink((key_serial_t) arg2, | |
1388 | (key_serial_t) arg3); | |
1389 | ||
1390 | case KEYCTL_SEARCH: | |
1391 | return keyctl_keyring_search((key_serial_t) arg2, | |
1392 | (const char __user *) arg3, | |
1393 | (const char __user *) arg4, | |
1394 | (key_serial_t) arg5); | |
1395 | ||
1396 | case KEYCTL_READ: | |
1397 | return keyctl_read_key((key_serial_t) arg2, | |
1398 | (char __user *) arg3, | |
1399 | (size_t) arg4); | |
1400 | ||
1401 | case KEYCTL_CHOWN: | |
1402 | return keyctl_chown_key((key_serial_t) arg2, | |
1403 | (uid_t) arg3, | |
1404 | (gid_t) arg4); | |
1405 | ||
1406 | case KEYCTL_SETPERM: | |
1407 | return keyctl_setperm_key((key_serial_t) arg2, | |
1408 | (key_perm_t) arg3); | |
1409 | ||
1410 | case KEYCTL_INSTANTIATE: | |
1411 | return keyctl_instantiate_key((key_serial_t) arg2, | |
1412 | (const void __user *) arg3, | |
1413 | (size_t) arg4, | |
1414 | (key_serial_t) arg5); | |
1415 | ||
1416 | case KEYCTL_NEGATE: | |
1417 | return keyctl_negate_key((key_serial_t) arg2, | |
1418 | (unsigned) arg3, | |
1419 | (key_serial_t) arg4); | |
1420 | ||
1421 | case KEYCTL_SET_REQKEY_KEYRING: | |
1422 | return keyctl_set_reqkey_keyring(arg2); | |
1423 | ||
1424 | case KEYCTL_SET_TIMEOUT: | |
1425 | return keyctl_set_timeout((key_serial_t) arg2, | |
1426 | (unsigned) arg3); | |
1427 | ||
1428 | case KEYCTL_ASSUME_AUTHORITY: | |
1429 | return keyctl_assume_authority((key_serial_t) arg2); | |
1430 | ||
1431 | case KEYCTL_GET_SECURITY: | |
1432 | return keyctl_get_security((key_serial_t) arg2, | |
1433 | (char __user *) arg3, | |
1434 | (size_t) arg4); | |
1435 | ||
1436 | case KEYCTL_SESSION_TO_PARENT: | |
1437 | return keyctl_session_to_parent(); | |
1438 | ||
1439 | default: | |
1440 | return -EOPNOTSUPP; | |
1441 | } | |
1442 | ||
1443 | } /* end sys_keyctl() */ |