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Commit | Line | Data |
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69664cf1 | 1 | /* Keyring handling |
1da177e4 | 2 | * |
b2a4df20 | 3 | * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved. |
1da177e4 LT |
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> | |
29db9190 | 16 | #include <linux/security.h> |
1da177e4 LT |
17 | #include <linux/seq_file.h> |
18 | #include <linux/err.h> | |
e9e349b0 | 19 | #include <keys/keyring-type.h> |
b2a4df20 DH |
20 | #include <keys/user-type.h> |
21 | #include <linux/assoc_array_priv.h> | |
512ea3bc | 22 | #include <linux/uaccess.h> |
1da177e4 LT |
23 | #include "internal.h" |
24 | ||
25 | /* | |
973c9f4f DH |
26 | * When plumbing the depths of the key tree, this sets a hard limit |
27 | * set on how deep we're willing to go. | |
1da177e4 LT |
28 | */ |
29 | #define KEYRING_SEARCH_MAX_DEPTH 6 | |
30 | ||
31 | /* | |
973c9f4f | 32 | * We keep all named keyrings in a hash to speed looking them up. |
1da177e4 LT |
33 | */ |
34 | #define KEYRING_NAME_HASH_SIZE (1 << 5) | |
35 | ||
b2a4df20 DH |
36 | /* |
37 | * We mark pointers we pass to the associative array with bit 1 set if | |
38 | * they're keyrings and clear otherwise. | |
39 | */ | |
40 | #define KEYRING_PTR_SUBTYPE 0x2UL | |
41 | ||
42 | static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x) | |
43 | { | |
44 | return (unsigned long)x & KEYRING_PTR_SUBTYPE; | |
45 | } | |
46 | static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x) | |
47 | { | |
48 | void *object = assoc_array_ptr_to_leaf(x); | |
49 | return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE); | |
50 | } | |
51 | static inline void *keyring_key_to_ptr(struct key *key) | |
52 | { | |
53 | if (key->type == &key_type_keyring) | |
54 | return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE); | |
55 | return key; | |
56 | } | |
57 | ||
1da177e4 LT |
58 | static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE]; |
59 | static DEFINE_RWLOCK(keyring_name_lock); | |
60 | ||
61 | static inline unsigned keyring_hash(const char *desc) | |
62 | { | |
63 | unsigned bucket = 0; | |
64 | ||
65 | for (; *desc; desc++) | |
c5b60b5e | 66 | bucket += (unsigned char)*desc; |
1da177e4 LT |
67 | |
68 | return bucket & (KEYRING_NAME_HASH_SIZE - 1); | |
69 | } | |
70 | ||
71 | /* | |
973c9f4f DH |
72 | * The keyring key type definition. Keyrings are simply keys of this type and |
73 | * can be treated as ordinary keys in addition to having their own special | |
74 | * operations. | |
1da177e4 | 75 | */ |
5d19e20b DH |
76 | static int keyring_preparse(struct key_preparsed_payload *prep); |
77 | static void keyring_free_preparse(struct key_preparsed_payload *prep); | |
1da177e4 | 78 | static int keyring_instantiate(struct key *keyring, |
cf7f601c | 79 | struct key_preparsed_payload *prep); |
31204ed9 | 80 | static void keyring_revoke(struct key *keyring); |
1da177e4 LT |
81 | static void keyring_destroy(struct key *keyring); |
82 | static void keyring_describe(const struct key *keyring, struct seq_file *m); | |
83 | static long keyring_read(const struct key *keyring, | |
84 | char __user *buffer, size_t buflen); | |
85 | ||
86 | struct key_type key_type_keyring = { | |
87 | .name = "keyring", | |
b2a4df20 | 88 | .def_datalen = 0, |
5d19e20b DH |
89 | .preparse = keyring_preparse, |
90 | .free_preparse = keyring_free_preparse, | |
1da177e4 | 91 | .instantiate = keyring_instantiate, |
31204ed9 | 92 | .revoke = keyring_revoke, |
1da177e4 LT |
93 | .destroy = keyring_destroy, |
94 | .describe = keyring_describe, | |
95 | .read = keyring_read, | |
96 | }; | |
7318226e DH |
97 | EXPORT_SYMBOL(key_type_keyring); |
98 | ||
1da177e4 | 99 | /* |
973c9f4f DH |
100 | * Semaphore to serialise link/link calls to prevent two link calls in parallel |
101 | * introducing a cycle. | |
1da177e4 | 102 | */ |
1ae8f407 | 103 | static DECLARE_RWSEM(keyring_serialise_link_sem); |
1da177e4 | 104 | |
1da177e4 | 105 | /* |
973c9f4f DH |
106 | * Publish the name of a keyring so that it can be found by name (if it has |
107 | * one). | |
1da177e4 | 108 | */ |
69664cf1 | 109 | static void keyring_publish_name(struct key *keyring) |
1da177e4 LT |
110 | { |
111 | int bucket; | |
112 | ||
113 | if (keyring->description) { | |
114 | bucket = keyring_hash(keyring->description); | |
115 | ||
116 | write_lock(&keyring_name_lock); | |
117 | ||
118 | if (!keyring_name_hash[bucket].next) | |
119 | INIT_LIST_HEAD(&keyring_name_hash[bucket]); | |
120 | ||
146aa8b1 | 121 | list_add_tail(&keyring->name_link, |
1da177e4 LT |
122 | &keyring_name_hash[bucket]); |
123 | ||
124 | write_unlock(&keyring_name_lock); | |
125 | } | |
a8b17ed0 | 126 | } |
1da177e4 | 127 | |
5d19e20b DH |
128 | /* |
129 | * Preparse a keyring payload | |
130 | */ | |
131 | static int keyring_preparse(struct key_preparsed_payload *prep) | |
132 | { | |
133 | return prep->datalen != 0 ? -EINVAL : 0; | |
134 | } | |
135 | ||
136 | /* | |
137 | * Free a preparse of a user defined key payload | |
138 | */ | |
139 | static void keyring_free_preparse(struct key_preparsed_payload *prep) | |
140 | { | |
141 | } | |
142 | ||
1da177e4 | 143 | /* |
973c9f4f DH |
144 | * Initialise a keyring. |
145 | * | |
146 | * Returns 0 on success, -EINVAL if given any data. | |
1da177e4 LT |
147 | */ |
148 | static int keyring_instantiate(struct key *keyring, | |
cf7f601c | 149 | struct key_preparsed_payload *prep) |
1da177e4 | 150 | { |
5d19e20b DH |
151 | assoc_array_init(&keyring->keys); |
152 | /* make the keyring available by name if it has one */ | |
153 | keyring_publish_name(keyring); | |
154 | return 0; | |
a8b17ed0 | 155 | } |
1da177e4 | 156 | |
1da177e4 | 157 | /* |
b2a4df20 DH |
158 | * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd |
159 | * fold the carry back too, but that requires inline asm. | |
160 | */ | |
161 | static u64 mult_64x32_and_fold(u64 x, u32 y) | |
162 | { | |
163 | u64 hi = (u64)(u32)(x >> 32) * y; | |
164 | u64 lo = (u64)(u32)(x) * y; | |
165 | return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); | |
166 | } | |
167 | ||
168 | /* | |
169 | * Hash a key type and description. | |
170 | */ | |
171 | static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) | |
172 | { | |
173 | const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; | |
d54e58b7 | 174 | const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; |
b2a4df20 DH |
175 | const char *description = index_key->description; |
176 | unsigned long hash, type; | |
177 | u32 piece; | |
178 | u64 acc; | |
179 | int n, desc_len = index_key->desc_len; | |
180 | ||
181 | type = (unsigned long)index_key->type; | |
182 | ||
183 | acc = mult_64x32_and_fold(type, desc_len + 13); | |
184 | acc = mult_64x32_and_fold(acc, 9207); | |
185 | for (;;) { | |
186 | n = desc_len; | |
187 | if (n <= 0) | |
188 | break; | |
189 | if (n > 4) | |
190 | n = 4; | |
191 | piece = 0; | |
192 | memcpy(&piece, description, n); | |
193 | description += n; | |
194 | desc_len -= n; | |
195 | acc = mult_64x32_and_fold(acc, piece); | |
196 | acc = mult_64x32_and_fold(acc, 9207); | |
197 | } | |
198 | ||
199 | /* Fold the hash down to 32 bits if need be. */ | |
200 | hash = acc; | |
201 | if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) | |
202 | hash ^= acc >> 32; | |
203 | ||
204 | /* Squidge all the keyrings into a separate part of the tree to | |
205 | * ordinary keys by making sure the lowest level segment in the hash is | |
206 | * zero for keyrings and non-zero otherwise. | |
207 | */ | |
d54e58b7 | 208 | if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) |
b2a4df20 | 209 | return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; |
d54e58b7 DH |
210 | if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) |
211 | return (hash + (hash << level_shift)) & ~fan_mask; | |
b2a4df20 DH |
212 | return hash; |
213 | } | |
214 | ||
215 | /* | |
216 | * Build the next index key chunk. | |
217 | * | |
218 | * On 32-bit systems the index key is laid out as: | |
219 | * | |
220 | * 0 4 5 9... | |
221 | * hash desclen typeptr desc[] | |
222 | * | |
223 | * On 64-bit systems: | |
224 | * | |
225 | * 0 8 9 17... | |
226 | * hash desclen typeptr desc[] | |
227 | * | |
228 | * We return it one word-sized chunk at a time. | |
1da177e4 | 229 | */ |
b2a4df20 DH |
230 | static unsigned long keyring_get_key_chunk(const void *data, int level) |
231 | { | |
232 | const struct keyring_index_key *index_key = data; | |
233 | unsigned long chunk = 0; | |
234 | long offset = 0; | |
235 | int desc_len = index_key->desc_len, n = sizeof(chunk); | |
236 | ||
237 | level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; | |
238 | switch (level) { | |
239 | case 0: | |
240 | return hash_key_type_and_desc(index_key); | |
241 | case 1: | |
242 | return ((unsigned long)index_key->type << 8) | desc_len; | |
243 | case 2: | |
244 | if (desc_len == 0) | |
245 | return (u8)((unsigned long)index_key->type >> | |
246 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
247 | n--; | |
248 | offset = 1; | |
249 | default: | |
250 | offset += sizeof(chunk) - 1; | |
251 | offset += (level - 3) * sizeof(chunk); | |
252 | if (offset >= desc_len) | |
253 | return 0; | |
254 | desc_len -= offset; | |
255 | if (desc_len > n) | |
256 | desc_len = n; | |
257 | offset += desc_len; | |
258 | do { | |
259 | chunk <<= 8; | |
260 | chunk |= ((u8*)index_key->description)[--offset]; | |
261 | } while (--desc_len > 0); | |
262 | ||
263 | if (level == 2) { | |
264 | chunk <<= 8; | |
265 | chunk |= (u8)((unsigned long)index_key->type >> | |
266 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
267 | } | |
268 | return chunk; | |
269 | } | |
270 | } | |
271 | ||
272 | static unsigned long keyring_get_object_key_chunk(const void *object, int level) | |
273 | { | |
274 | const struct key *key = keyring_ptr_to_key(object); | |
275 | return keyring_get_key_chunk(&key->index_key, level); | |
276 | } | |
277 | ||
278 | static bool keyring_compare_object(const void *object, const void *data) | |
1da177e4 | 279 | { |
b2a4df20 DH |
280 | const struct keyring_index_key *index_key = data; |
281 | const struct key *key = keyring_ptr_to_key(object); | |
282 | ||
283 | return key->index_key.type == index_key->type && | |
284 | key->index_key.desc_len == index_key->desc_len && | |
285 | memcmp(key->index_key.description, index_key->description, | |
286 | index_key->desc_len) == 0; | |
a8b17ed0 | 287 | } |
1da177e4 | 288 | |
b2a4df20 DH |
289 | /* |
290 | * Compare the index keys of a pair of objects and determine the bit position | |
291 | * at which they differ - if they differ. | |
292 | */ | |
23fd78d7 | 293 | static int keyring_diff_objects(const void *object, const void *data) |
b2a4df20 | 294 | { |
23fd78d7 | 295 | const struct key *key_a = keyring_ptr_to_key(object); |
b2a4df20 | 296 | const struct keyring_index_key *a = &key_a->index_key; |
23fd78d7 | 297 | const struct keyring_index_key *b = data; |
b2a4df20 DH |
298 | unsigned long seg_a, seg_b; |
299 | int level, i; | |
300 | ||
301 | level = 0; | |
302 | seg_a = hash_key_type_and_desc(a); | |
303 | seg_b = hash_key_type_and_desc(b); | |
304 | if ((seg_a ^ seg_b) != 0) | |
305 | goto differ; | |
306 | ||
307 | /* The number of bits contributed by the hash is controlled by a | |
308 | * constant in the assoc_array headers. Everything else thereafter we | |
309 | * can deal with as being machine word-size dependent. | |
310 | */ | |
311 | level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; | |
312 | seg_a = a->desc_len; | |
313 | seg_b = b->desc_len; | |
314 | if ((seg_a ^ seg_b) != 0) | |
315 | goto differ; | |
316 | ||
317 | /* The next bit may not work on big endian */ | |
318 | level++; | |
319 | seg_a = (unsigned long)a->type; | |
320 | seg_b = (unsigned long)b->type; | |
321 | if ((seg_a ^ seg_b) != 0) | |
322 | goto differ; | |
323 | ||
324 | level += sizeof(unsigned long); | |
325 | if (a->desc_len == 0) | |
326 | goto same; | |
327 | ||
328 | i = 0; | |
329 | if (((unsigned long)a->description | (unsigned long)b->description) & | |
330 | (sizeof(unsigned long) - 1)) { | |
331 | do { | |
332 | seg_a = *(unsigned long *)(a->description + i); | |
333 | seg_b = *(unsigned long *)(b->description + i); | |
334 | if ((seg_a ^ seg_b) != 0) | |
335 | goto differ_plus_i; | |
336 | i += sizeof(unsigned long); | |
337 | } while (i < (a->desc_len & (sizeof(unsigned long) - 1))); | |
338 | } | |
339 | ||
340 | for (; i < a->desc_len; i++) { | |
341 | seg_a = *(unsigned char *)(a->description + i); | |
342 | seg_b = *(unsigned char *)(b->description + i); | |
343 | if ((seg_a ^ seg_b) != 0) | |
344 | goto differ_plus_i; | |
345 | } | |
346 | ||
347 | same: | |
348 | return -1; | |
349 | ||
350 | differ_plus_i: | |
351 | level += i; | |
352 | differ: | |
353 | i = level * 8 + __ffs(seg_a ^ seg_b); | |
354 | return i; | |
355 | } | |
356 | ||
357 | /* | |
358 | * Free an object after stripping the keyring flag off of the pointer. | |
359 | */ | |
360 | static void keyring_free_object(void *object) | |
361 | { | |
362 | key_put(keyring_ptr_to_key(object)); | |
363 | } | |
364 | ||
365 | /* | |
366 | * Operations for keyring management by the index-tree routines. | |
367 | */ | |
368 | static const struct assoc_array_ops keyring_assoc_array_ops = { | |
369 | .get_key_chunk = keyring_get_key_chunk, | |
370 | .get_object_key_chunk = keyring_get_object_key_chunk, | |
371 | .compare_object = keyring_compare_object, | |
372 | .diff_objects = keyring_diff_objects, | |
373 | .free_object = keyring_free_object, | |
374 | }; | |
375 | ||
1da177e4 | 376 | /* |
973c9f4f DH |
377 | * Clean up a keyring when it is destroyed. Unpublish its name if it had one |
378 | * and dispose of its data. | |
233e4735 DH |
379 | * |
380 | * The garbage collector detects the final key_put(), removes the keyring from | |
381 | * the serial number tree and then does RCU synchronisation before coming here, | |
382 | * so we shouldn't need to worry about code poking around here with the RCU | |
383 | * readlock held by this time. | |
1da177e4 LT |
384 | */ |
385 | static void keyring_destroy(struct key *keyring) | |
386 | { | |
1da177e4 LT |
387 | if (keyring->description) { |
388 | write_lock(&keyring_name_lock); | |
94efe72f | 389 | |
146aa8b1 DH |
390 | if (keyring->name_link.next != NULL && |
391 | !list_empty(&keyring->name_link)) | |
392 | list_del(&keyring->name_link); | |
94efe72f | 393 | |
1da177e4 LT |
394 | write_unlock(&keyring_name_lock); |
395 | } | |
396 | ||
2b6aa412 MM |
397 | if (keyring->restrict_link) { |
398 | struct key_restriction *keyres = keyring->restrict_link; | |
399 | ||
400 | key_put(keyres->key); | |
401 | kfree(keyres); | |
402 | } | |
403 | ||
b2a4df20 | 404 | assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); |
a8b17ed0 | 405 | } |
1da177e4 | 406 | |
1da177e4 | 407 | /* |
973c9f4f | 408 | * Describe a keyring for /proc. |
1da177e4 LT |
409 | */ |
410 | static void keyring_describe(const struct key *keyring, struct seq_file *m) | |
411 | { | |
c8563473 | 412 | if (keyring->description) |
1da177e4 | 413 | seq_puts(m, keyring->description); |
c8563473 | 414 | else |
1da177e4 | 415 | seq_puts(m, "[anon]"); |
1da177e4 | 416 | |
78b7280c | 417 | if (key_is_instantiated(keyring)) { |
b2a4df20 DH |
418 | if (keyring->keys.nr_leaves_on_tree != 0) |
419 | seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); | |
78b7280c DH |
420 | else |
421 | seq_puts(m, ": empty"); | |
78b7280c | 422 | } |
a8b17ed0 | 423 | } |
1da177e4 | 424 | |
b2a4df20 DH |
425 | struct keyring_read_iterator_context { |
426 | size_t qty; | |
427 | size_t count; | |
428 | key_serial_t __user *buffer; | |
429 | }; | |
430 | ||
431 | static int keyring_read_iterator(const void *object, void *data) | |
432 | { | |
433 | struct keyring_read_iterator_context *ctx = data; | |
434 | const struct key *key = keyring_ptr_to_key(object); | |
435 | int ret; | |
436 | ||
437 | kenter("{%s,%d},,{%zu/%zu}", | |
438 | key->type->name, key->serial, ctx->count, ctx->qty); | |
439 | ||
440 | if (ctx->count >= ctx->qty) | |
441 | return 1; | |
442 | ||
443 | ret = put_user(key->serial, ctx->buffer); | |
444 | if (ret < 0) | |
445 | return ret; | |
446 | ctx->buffer++; | |
447 | ctx->count += sizeof(key->serial); | |
448 | return 0; | |
449 | } | |
450 | ||
1da177e4 | 451 | /* |
973c9f4f DH |
452 | * Read a list of key IDs from the keyring's contents in binary form |
453 | * | |
b2a4df20 DH |
454 | * The keyring's semaphore is read-locked by the caller. This prevents someone |
455 | * from modifying it under us - which could cause us to read key IDs multiple | |
456 | * times. | |
1da177e4 LT |
457 | */ |
458 | static long keyring_read(const struct key *keyring, | |
459 | char __user *buffer, size_t buflen) | |
460 | { | |
b2a4df20 DH |
461 | struct keyring_read_iterator_context ctx; |
462 | unsigned long nr_keys; | |
463 | int ret; | |
1da177e4 | 464 | |
b2a4df20 DH |
465 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
466 | ||
467 | if (buflen & (sizeof(key_serial_t) - 1)) | |
468 | return -EINVAL; | |
469 | ||
470 | nr_keys = keyring->keys.nr_leaves_on_tree; | |
471 | if (nr_keys == 0) | |
472 | return 0; | |
1da177e4 | 473 | |
b2a4df20 DH |
474 | /* Calculate how much data we could return */ |
475 | ctx.qty = nr_keys * sizeof(key_serial_t); | |
476 | ||
477 | if (!buffer || !buflen) | |
478 | return ctx.qty; | |
479 | ||
480 | if (buflen > ctx.qty) | |
481 | ctx.qty = buflen; | |
482 | ||
483 | /* Copy the IDs of the subscribed keys into the buffer */ | |
484 | ctx.buffer = (key_serial_t __user *)buffer; | |
485 | ctx.count = 0; | |
486 | ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx); | |
487 | if (ret < 0) { | |
488 | kleave(" = %d [iterate]", ret); | |
489 | return ret; | |
1da177e4 LT |
490 | } |
491 | ||
b2a4df20 DH |
492 | kleave(" = %zu [ok]", ctx.count); |
493 | return ctx.count; | |
a8b17ed0 | 494 | } |
1da177e4 | 495 | |
1da177e4 | 496 | /* |
973c9f4f | 497 | * Allocate a keyring and link into the destination keyring. |
1da177e4 | 498 | */ |
9a56c2db | 499 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
96b5c8fe | 500 | const struct cred *cred, key_perm_t perm, |
5ac7eace | 501 | unsigned long flags, |
2b6aa412 | 502 | struct key_restriction *restrict_link, |
5ac7eace | 503 | struct key *dest) |
1da177e4 LT |
504 | { |
505 | struct key *keyring; | |
506 | int ret; | |
507 | ||
508 | keyring = key_alloc(&key_type_keyring, description, | |
5ac7eace | 509 | uid, gid, cred, perm, flags, restrict_link); |
1da177e4 | 510 | if (!IS_ERR(keyring)) { |
3e30148c | 511 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
512 | if (ret < 0) { |
513 | key_put(keyring); | |
514 | keyring = ERR_PTR(ret); | |
515 | } | |
516 | } | |
517 | ||
518 | return keyring; | |
a8b17ed0 | 519 | } |
f8aa23a5 | 520 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 521 | |
5ac7eace DH |
522 | /** |
523 | * restrict_link_reject - Give -EPERM to restrict link | |
524 | * @keyring: The keyring being added to. | |
525 | * @type: The type of key being added. | |
5ac7eace | 526 | * @payload: The payload of the key intended to be added. |
aaf66c88 | 527 | * @data: Additional data for evaluating restriction. |
5ac7eace DH |
528 | * |
529 | * Reject the addition of any links to a keyring. It can be overridden by | |
530 | * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when | |
531 | * adding a key to a keyring. | |
532 | * | |
2b6aa412 MM |
533 | * This is meant to be stored in a key_restriction structure which is passed |
534 | * in the restrict_link parameter to keyring_alloc(). | |
5ac7eace DH |
535 | */ |
536 | int restrict_link_reject(struct key *keyring, | |
537 | const struct key_type *type, | |
aaf66c88 MM |
538 | const union key_payload *payload, |
539 | struct key *restriction_key) | |
5ac7eace DH |
540 | { |
541 | return -EPERM; | |
542 | } | |
543 | ||
c06cfb08 DH |
544 | /* |
545 | * By default, we keys found by getting an exact match on their descriptions. | |
546 | */ | |
0c903ab6 DH |
547 | bool key_default_cmp(const struct key *key, |
548 | const struct key_match_data *match_data) | |
c06cfb08 DH |
549 | { |
550 | return strcmp(key->description, match_data->raw_data) == 0; | |
551 | } | |
552 | ||
b2a4df20 DH |
553 | /* |
554 | * Iteration function to consider each key found. | |
1da177e4 | 555 | */ |
b2a4df20 | 556 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 557 | { |
b2a4df20 DH |
558 | struct keyring_search_context *ctx = iterator_data; |
559 | const struct key *key = keyring_ptr_to_key(object); | |
560 | unsigned long kflags = key->flags; | |
1da177e4 | 561 | |
b2a4df20 | 562 | kenter("{%d}", key->serial); |
1da177e4 | 563 | |
b2a4df20 DH |
564 | /* ignore keys not of this type */ |
565 | if (key->type != ctx->index_key.type) { | |
566 | kleave(" = 0 [!type]"); | |
567 | return 0; | |
29db9190 | 568 | } |
1da177e4 | 569 | |
b2a4df20 DH |
570 | /* skip invalidated, revoked and expired keys */ |
571 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
572 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | | |
573 | (1 << KEY_FLAG_REVOKED))) { | |
574 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
575 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
576 | goto skipped; | |
577 | } | |
1da177e4 | 578 | |
b2a4df20 | 579 | if (key->expiry && ctx->now.tv_sec >= key->expiry) { |
0b0a8415 DH |
580 | if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) |
581 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
b2a4df20 DH |
582 | kleave(" = %d [expire]", ctx->skipped_ret); |
583 | goto skipped; | |
584 | } | |
585 | } | |
664cceb0 | 586 | |
b2a4df20 | 587 | /* keys that don't match */ |
46291959 | 588 | if (!ctx->match_data.cmp(key, &ctx->match_data)) { |
b2a4df20 DH |
589 | kleave(" = 0 [!match]"); |
590 | return 0; | |
591 | } | |
dceba994 | 592 | |
b2a4df20 DH |
593 | /* key must have search permissions */ |
594 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
595 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 596 | ctx->cred, KEY_NEED_SEARCH) < 0) { |
b2a4df20 DH |
597 | ctx->result = ERR_PTR(-EACCES); |
598 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
599 | goto skipped; | |
dceba994 KC |
600 | } |
601 | ||
b2a4df20 DH |
602 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
603 | /* we set a different error code if we pass a negative key */ | |
604 | if (kflags & (1 << KEY_FLAG_NEGATIVE)) { | |
74792b00 | 605 | smp_rmb(); |
146aa8b1 | 606 | ctx->result = ERR_PTR(key->reject_error); |
b2a4df20 DH |
607 | kleave(" = %d [neg]", ctx->skipped_ret); |
608 | goto skipped; | |
609 | } | |
610 | } | |
1da177e4 | 611 | |
b2a4df20 DH |
612 | /* Found */ |
613 | ctx->result = make_key_ref(key, ctx->possessed); | |
614 | kleave(" = 1 [found]"); | |
615 | return 1; | |
1da177e4 | 616 | |
b2a4df20 DH |
617 | skipped: |
618 | return ctx->skipped_ret; | |
619 | } | |
1da177e4 | 620 | |
b2a4df20 DH |
621 | /* |
622 | * Search inside a keyring for a key. We can search by walking to it | |
623 | * directly based on its index-key or we can iterate over the entire | |
624 | * tree looking for it, based on the match function. | |
625 | */ | |
626 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
627 | { | |
46291959 | 628 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { |
b2a4df20 DH |
629 | const void *object; |
630 | ||
631 | object = assoc_array_find(&keyring->keys, | |
632 | &keyring_assoc_array_ops, | |
633 | &ctx->index_key); | |
634 | return object ? ctx->iterator(object, ctx) : 0; | |
635 | } | |
636 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
637 | } | |
1da177e4 | 638 | |
b2a4df20 DH |
639 | /* |
640 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
641 | * depth. | |
642 | */ | |
643 | static bool search_nested_keyrings(struct key *keyring, | |
644 | struct keyring_search_context *ctx) | |
645 | { | |
646 | struct { | |
647 | struct key *keyring; | |
648 | struct assoc_array_node *node; | |
649 | int slot; | |
650 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 651 | |
b2a4df20 DH |
652 | struct assoc_array_shortcut *shortcut; |
653 | struct assoc_array_node *node; | |
654 | struct assoc_array_ptr *ptr; | |
655 | struct key *key; | |
656 | int sp = 0, slot; | |
1da177e4 | 657 | |
b2a4df20 DH |
658 | kenter("{%d},{%s,%s}", |
659 | keyring->serial, | |
660 | ctx->index_key.type->name, | |
661 | ctx->index_key.description); | |
1da177e4 | 662 | |
054f6180 DH |
663 | #define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK) |
664 | BUG_ON((ctx->flags & STATE_CHECKS) == 0 || | |
665 | (ctx->flags & STATE_CHECKS) == STATE_CHECKS); | |
666 | ||
b2a4df20 DH |
667 | if (ctx->index_key.description) |
668 | ctx->index_key.desc_len = strlen(ctx->index_key.description); | |
1da177e4 | 669 | |
b2a4df20 DH |
670 | /* Check to see if this top-level keyring is what we are looking for |
671 | * and whether it is valid or not. | |
672 | */ | |
46291959 | 673 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || |
b2a4df20 DH |
674 | keyring_compare_object(keyring, &ctx->index_key)) { |
675 | ctx->skipped_ret = 2; | |
b2a4df20 DH |
676 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { |
677 | case 1: | |
78b7280c | 678 | goto found; |
b2a4df20 DH |
679 | case 2: |
680 | return false; | |
681 | default: | |
682 | break; | |
1da177e4 | 683 | } |
b2a4df20 | 684 | } |
1da177e4 | 685 | |
b2a4df20 | 686 | ctx->skipped_ret = 0; |
b2a4df20 DH |
687 | |
688 | /* Start processing a new keyring */ | |
689 | descend_to_keyring: | |
690 | kdebug("descend to %d", keyring->serial); | |
691 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
692 | (1 << KEY_FLAG_REVOKED))) | |
693 | goto not_this_keyring; | |
694 | ||
695 | /* Search through the keys in this keyring before its searching its | |
696 | * subtrees. | |
697 | */ | |
698 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 699 | goto found; |
1da177e4 | 700 | |
b2a4df20 DH |
701 | /* Then manually iterate through the keyrings nested in this one. |
702 | * | |
703 | * Start from the root node of the index tree. Because of the way the | |
704 | * hash function has been set up, keyrings cluster on the leftmost | |
705 | * branch of the root node (root slot 0) or in the root node itself. | |
706 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
707 | * slots 1-15). | |
708 | */ | |
709 | ptr = ACCESS_ONCE(keyring->keys.root); | |
710 | if (!ptr) | |
711 | goto not_this_keyring; | |
1da177e4 | 712 | |
b2a4df20 DH |
713 | if (assoc_array_ptr_is_shortcut(ptr)) { |
714 | /* If the root is a shortcut, either the keyring only contains | |
715 | * keyring pointers (everything clusters behind root slot 0) or | |
716 | * doesn't contain any keyring pointers. | |
1da177e4 | 717 | */ |
b2a4df20 DH |
718 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
719 | smp_read_barrier_depends(); | |
720 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) | |
721 | goto not_this_keyring; | |
722 | ||
723 | ptr = ACCESS_ONCE(shortcut->next_node); | |
724 | node = assoc_array_ptr_to_node(ptr); | |
725 | goto begin_node; | |
726 | } | |
727 | ||
728 | node = assoc_array_ptr_to_node(ptr); | |
729 | smp_read_barrier_depends(); | |
730 | ||
731 | ptr = node->slots[0]; | |
732 | if (!assoc_array_ptr_is_meta(ptr)) | |
733 | goto begin_node; | |
734 | ||
735 | descend_to_node: | |
736 | /* Descend to a more distal node in this keyring's content tree and go | |
737 | * through that. | |
738 | */ | |
739 | kdebug("descend"); | |
740 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
741 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
742 | smp_read_barrier_depends(); | |
743 | ptr = ACCESS_ONCE(shortcut->next_node); | |
744 | BUG_ON(!assoc_array_ptr_is_node(ptr)); | |
b2a4df20 | 745 | } |
9c5e45df | 746 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
747 | |
748 | begin_node: | |
749 | kdebug("begin_node"); | |
750 | smp_read_barrier_depends(); | |
751 | slot = 0; | |
752 | ascend_to_node: | |
753 | /* Go through the slots in a node */ | |
754 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
755 | ptr = ACCESS_ONCE(node->slots[slot]); | |
756 | ||
757 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
758 | goto descend_to_node; | |
759 | ||
760 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 761 | continue; |
1da177e4 | 762 | |
b2a4df20 DH |
763 | key = keyring_ptr_to_key(ptr); |
764 | ||
765 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
766 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
767 | ctx->result = ERR_PTR(-ELOOP); | |
768 | return false; | |
769 | } | |
770 | goto not_this_keyring; | |
771 | } | |
772 | ||
773 | /* Search a nested keyring */ | |
774 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
775 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 776 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 777 | continue; |
1da177e4 LT |
778 | |
779 | /* stack the current position */ | |
31d5a79d | 780 | stack[sp].keyring = keyring; |
b2a4df20 DH |
781 | stack[sp].node = node; |
782 | stack[sp].slot = slot; | |
1da177e4 LT |
783 | sp++; |
784 | ||
785 | /* begin again with the new keyring */ | |
786 | keyring = key; | |
b2a4df20 DH |
787 | goto descend_to_keyring; |
788 | } | |
789 | ||
790 | /* We've dealt with all the slots in the current node, so now we need | |
791 | * to ascend to the parent and continue processing there. | |
792 | */ | |
793 | ptr = ACCESS_ONCE(node->back_pointer); | |
794 | slot = node->parent_slot; | |
795 | ||
796 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
797 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
798 | smp_read_barrier_depends(); | |
799 | ptr = ACCESS_ONCE(shortcut->back_pointer); | |
800 | slot = shortcut->parent_slot; | |
801 | } | |
802 | if (!ptr) | |
803 | goto not_this_keyring; | |
804 | node = assoc_array_ptr_to_node(ptr); | |
805 | smp_read_barrier_depends(); | |
806 | slot++; | |
807 | ||
808 | /* If we've ascended to the root (zero backpointer), we must have just | |
809 | * finished processing the leftmost branch rather than the root slots - | |
810 | * so there can't be any more keyrings for us to find. | |
811 | */ | |
812 | if (node->back_pointer) { | |
813 | kdebug("ascend %d", slot); | |
814 | goto ascend_to_node; | |
1da177e4 LT |
815 | } |
816 | ||
b2a4df20 DH |
817 | /* The keyring we're looking at was disqualified or didn't contain a |
818 | * matching key. | |
819 | */ | |
664cceb0 | 820 | not_this_keyring: |
b2a4df20 DH |
821 | kdebug("not_this_keyring %d", sp); |
822 | if (sp <= 0) { | |
823 | kleave(" = false"); | |
824 | return false; | |
1da177e4 LT |
825 | } |
826 | ||
b2a4df20 DH |
827 | /* Resume the processing of a keyring higher up in the tree */ |
828 | sp--; | |
829 | keyring = stack[sp].keyring; | |
830 | node = stack[sp].node; | |
831 | slot = stack[sp].slot + 1; | |
832 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
833 | goto ascend_to_node; | |
1da177e4 | 834 | |
b2a4df20 | 835 | /* We found a viable match */ |
664cceb0 | 836 | found: |
b2a4df20 | 837 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 838 | key_check(key); |
b2a4df20 DH |
839 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
840 | key->last_used_at = ctx->now.tv_sec; | |
841 | keyring->last_used_at = ctx->now.tv_sec; | |
842 | while (sp > 0) | |
843 | stack[--sp].keyring->last_used_at = ctx->now.tv_sec; | |
844 | } | |
845 | kleave(" = true"); | |
846 | return true; | |
847 | } | |
848 | ||
849 | /** | |
850 | * keyring_search_aux - Search a keyring tree for a key matching some criteria | |
851 | * @keyring_ref: A pointer to the keyring with possession indicator. | |
852 | * @ctx: The keyring search context. | |
853 | * | |
854 | * Search the supplied keyring tree for a key that matches the criteria given. | |
855 | * The root keyring and any linked keyrings must grant Search permission to the | |
856 | * caller to be searchable and keys can only be found if they too grant Search | |
857 | * to the caller. The possession flag on the root keyring pointer controls use | |
858 | * of the possessor bits in permissions checking of the entire tree. In | |
859 | * addition, the LSM gets to forbid keyring searches and key matches. | |
860 | * | |
861 | * The search is performed as a breadth-then-depth search up to the prescribed | |
862 | * limit (KEYRING_SEARCH_MAX_DEPTH). | |
863 | * | |
864 | * Keys are matched to the type provided and are then filtered by the match | |
865 | * function, which is given the description to use in any way it sees fit. The | |
866 | * match function may use any attributes of a key that it wishes to to | |
867 | * determine the match. Normally the match function from the key type would be | |
868 | * used. | |
869 | * | |
870 | * RCU can be used to prevent the keyring key lists from disappearing without | |
871 | * the need to take lots of locks. | |
872 | * | |
873 | * Returns a pointer to the found key and increments the key usage count if | |
874 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
875 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
876 | * specified keyring wasn't a keyring. | |
877 | * | |
878 | * In the case of a successful return, the possession attribute from | |
879 | * @keyring_ref is propagated to the returned key reference. | |
880 | */ | |
881 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, | |
882 | struct keyring_search_context *ctx) | |
883 | { | |
884 | struct key *keyring; | |
885 | long err; | |
886 | ||
887 | ctx->iterator = keyring_search_iterator; | |
888 | ctx->possessed = is_key_possessed(keyring_ref); | |
889 | ctx->result = ERR_PTR(-EAGAIN); | |
890 | ||
891 | keyring = key_ref_to_ptr(keyring_ref); | |
892 | key_check(keyring); | |
893 | ||
894 | if (keyring->type != &key_type_keyring) | |
895 | return ERR_PTR(-ENOTDIR); | |
896 | ||
897 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 898 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
899 | if (err < 0) |
900 | return ERR_PTR(err); | |
901 | } | |
902 | ||
903 | rcu_read_lock(); | |
904 | ctx->now = current_kernel_time(); | |
905 | if (search_nested_keyrings(keyring, ctx)) | |
906 | __key_get(key_ref_to_ptr(ctx->result)); | |
76d8aeab | 907 | rcu_read_unlock(); |
b2a4df20 | 908 | return ctx->result; |
a8b17ed0 | 909 | } |
1da177e4 | 910 | |
973c9f4f DH |
911 | /** |
912 | * keyring_search - Search the supplied keyring tree for a matching key | |
913 | * @keyring: The root of the keyring tree to be searched. | |
914 | * @type: The type of keyring we want to find. | |
915 | * @description: The name of the keyring we want to find. | |
916 | * | |
917 | * As keyring_search_aux() above, but using the current task's credentials and | |
b2a4df20 | 918 | * type's default matching function and preferred search method. |
1da177e4 | 919 | */ |
664cceb0 DH |
920 | key_ref_t keyring_search(key_ref_t keyring, |
921 | struct key_type *type, | |
922 | const char *description) | |
1da177e4 | 923 | { |
4bdf0bc3 DH |
924 | struct keyring_search_context ctx = { |
925 | .index_key.type = type, | |
926 | .index_key.description = description, | |
927 | .cred = current_cred(), | |
c06cfb08 | 928 | .match_data.cmp = key_default_cmp, |
46291959 DH |
929 | .match_data.raw_data = description, |
930 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
931 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 932 | }; |
46291959 DH |
933 | key_ref_t key; |
934 | int ret; | |
4bdf0bc3 | 935 | |
46291959 DH |
936 | if (type->match_preparse) { |
937 | ret = type->match_preparse(&ctx.match_data); | |
938 | if (ret < 0) | |
939 | return ERR_PTR(ret); | |
940 | } | |
941 | ||
942 | key = keyring_search_aux(keyring, &ctx); | |
943 | ||
944 | if (type->match_free) | |
945 | type->match_free(&ctx.match_data); | |
946 | return key; | |
a8b17ed0 | 947 | } |
1da177e4 LT |
948 | EXPORT_SYMBOL(keyring_search); |
949 | ||
6563c91f MM |
950 | static struct key_restriction *keyring_restriction_alloc( |
951 | key_restrict_link_func_t check) | |
952 | { | |
953 | struct key_restriction *keyres = | |
954 | kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
955 | ||
956 | if (!keyres) | |
957 | return ERR_PTR(-ENOMEM); | |
958 | ||
959 | keyres->check = check; | |
960 | ||
961 | return keyres; | |
962 | } | |
963 | ||
964 | /* | |
965 | * Semaphore to serialise restriction setup to prevent reference count | |
966 | * cycles through restriction key pointers. | |
967 | */ | |
968 | static DECLARE_RWSEM(keyring_serialise_restrict_sem); | |
969 | ||
970 | /* | |
971 | * Check for restriction cycles that would prevent keyring garbage collection. | |
972 | * keyring_serialise_restrict_sem must be held. | |
973 | */ | |
974 | static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, | |
975 | struct key_restriction *keyres) | |
976 | { | |
977 | while (keyres && keyres->key && | |
978 | keyres->key->type == &key_type_keyring) { | |
979 | if (keyres->key == dest_keyring) | |
980 | return true; | |
981 | ||
982 | keyres = keyres->key->restrict_link; | |
983 | } | |
984 | ||
985 | return false; | |
986 | } | |
987 | ||
988 | /** | |
989 | * keyring_restrict - Look up and apply a restriction to a keyring | |
990 | * | |
991 | * @keyring: The keyring to be restricted | |
992 | * @restriction: The restriction options to apply to the keyring | |
993 | */ | |
994 | int keyring_restrict(key_ref_t keyring_ref, const char *type, | |
995 | const char *restriction) | |
996 | { | |
997 | struct key *keyring; | |
998 | struct key_type *restrict_type = NULL; | |
999 | struct key_restriction *restrict_link; | |
1000 | int ret = 0; | |
1001 | ||
1002 | keyring = key_ref_to_ptr(keyring_ref); | |
1003 | key_check(keyring); | |
1004 | ||
1005 | if (keyring->type != &key_type_keyring) | |
1006 | return -ENOTDIR; | |
1007 | ||
1008 | if (!type) { | |
1009 | restrict_link = keyring_restriction_alloc(restrict_link_reject); | |
1010 | } else { | |
1011 | restrict_type = key_type_lookup(type); | |
1012 | ||
1013 | if (IS_ERR(restrict_type)) | |
1014 | return PTR_ERR(restrict_type); | |
1015 | ||
1016 | if (!restrict_type->lookup_restriction) { | |
1017 | ret = -ENOENT; | |
1018 | goto error; | |
1019 | } | |
1020 | ||
1021 | restrict_link = restrict_type->lookup_restriction(restriction); | |
1022 | } | |
1023 | ||
1024 | if (IS_ERR(restrict_link)) { | |
1025 | ret = PTR_ERR(restrict_link); | |
1026 | goto error; | |
1027 | } | |
1028 | ||
1029 | down_write(&keyring->sem); | |
1030 | down_write(&keyring_serialise_restrict_sem); | |
1031 | ||
1032 | if (keyring->restrict_link) | |
1033 | ret = -EEXIST; | |
1034 | else if (keyring_detect_restriction_cycle(keyring, restrict_link)) | |
1035 | ret = -EDEADLK; | |
1036 | else | |
1037 | keyring->restrict_link = restrict_link; | |
1038 | ||
1039 | up_write(&keyring_serialise_restrict_sem); | |
1040 | up_write(&keyring->sem); | |
1041 | ||
1042 | if (ret < 0) { | |
1043 | key_put(restrict_link->key); | |
1044 | kfree(restrict_link); | |
1045 | } | |
1046 | ||
1047 | error: | |
1048 | if (restrict_type) | |
1049 | key_type_put(restrict_type); | |
1050 | ||
1051 | return ret; | |
1052 | } | |
1053 | EXPORT_SYMBOL(keyring_restrict); | |
1054 | ||
1da177e4 | 1055 | /* |
b2a4df20 | 1056 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
1057 | * |
1058 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
1059 | * permission is granted to modify the keyring as no check is made here. The |
1060 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
1061 | * |
1062 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
1063 | * successful and returns NULL if not found. Revoked and invalidated keys are |
1064 | * skipped over. | |
973c9f4f DH |
1065 | * |
1066 | * If successful, the possession indicator is propagated from the keyring ref | |
1067 | * to the returned key reference. | |
1da177e4 | 1068 | */ |
b2a4df20 DH |
1069 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
1070 | const struct keyring_index_key *index_key) | |
1da177e4 | 1071 | { |
664cceb0 | 1072 | struct key *keyring, *key; |
b2a4df20 | 1073 | const void *object; |
1da177e4 | 1074 | |
664cceb0 | 1075 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 1076 | |
b2a4df20 DH |
1077 | kenter("{%d},{%s,%s}", |
1078 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 1079 | |
b2a4df20 DH |
1080 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
1081 | index_key); | |
1da177e4 | 1082 | |
b2a4df20 DH |
1083 | if (object) |
1084 | goto found; | |
1085 | ||
1086 | kleave(" = NULL"); | |
1087 | return NULL; | |
1da177e4 | 1088 | |
c5b60b5e | 1089 | found: |
b2a4df20 DH |
1090 | key = keyring_ptr_to_key(object); |
1091 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
1092 | (1 << KEY_FLAG_REVOKED))) { | |
1093 | kleave(" = NULL [x]"); | |
1094 | return NULL; | |
1095 | } | |
ccc3e6d9 | 1096 | __key_get(key); |
b2a4df20 DH |
1097 | kleave(" = {%d}", key->serial); |
1098 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 1099 | } |
1da177e4 | 1100 | |
1da177e4 | 1101 | /* |
973c9f4f DH |
1102 | * Find a keyring with the specified name. |
1103 | * | |
1104 | * All named keyrings in the current user namespace are searched, provided they | |
1105 | * grant Search permission directly to the caller (unless this check is | |
1106 | * skipped). Keyrings whose usage points have reached zero or who have been | |
1107 | * revoked are skipped. | |
1108 | * | |
1109 | * Returns a pointer to the keyring with the keyring's refcount having being | |
1110 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 1111 | */ |
69664cf1 | 1112 | struct key *find_keyring_by_name(const char *name, bool skip_perm_check) |
1da177e4 LT |
1113 | { |
1114 | struct key *keyring; | |
1115 | int bucket; | |
1116 | ||
1da177e4 | 1117 | if (!name) |
cea7daa3 | 1118 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
1119 | |
1120 | bucket = keyring_hash(name); | |
1121 | ||
1122 | read_lock(&keyring_name_lock); | |
1123 | ||
1124 | if (keyring_name_hash[bucket].next) { | |
1125 | /* search this hash bucket for a keyring with a matching name | |
1126 | * that's readable and that hasn't been revoked */ | |
1127 | list_for_each_entry(keyring, | |
1128 | &keyring_name_hash[bucket], | |
146aa8b1 | 1129 | name_link |
1da177e4 | 1130 | ) { |
9a56c2db | 1131 | if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) |
2ea190d0 SH |
1132 | continue; |
1133 | ||
76d8aeab | 1134 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1da177e4 LT |
1135 | continue; |
1136 | ||
1137 | if (strcmp(keyring->description, name) != 0) | |
1138 | continue; | |
1139 | ||
69664cf1 DH |
1140 | if (!skip_perm_check && |
1141 | key_permission(make_key_ref(keyring, 0), | |
f5895943 | 1142 | KEY_NEED_SEARCH) < 0) |
1da177e4 LT |
1143 | continue; |
1144 | ||
cea7daa3 TO |
1145 | /* we've got a match but we might end up racing with |
1146 | * key_cleanup() if the keyring is currently 'dead' | |
1147 | * (ie. it has a zero usage count) */ | |
fff29291 | 1148 | if (!refcount_inc_not_zero(&keyring->usage)) |
cea7daa3 | 1149 | continue; |
31d5a79d | 1150 | keyring->last_used_at = current_kernel_time().tv_sec; |
cea7daa3 | 1151 | goto out; |
1da177e4 LT |
1152 | } |
1153 | } | |
1154 | ||
1da177e4 | 1155 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1156 | out: |
1157 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1158 | return keyring; |
a8b17ed0 | 1159 | } |
1da177e4 | 1160 | |
b2a4df20 DH |
1161 | static int keyring_detect_cycle_iterator(const void *object, |
1162 | void *iterator_data) | |
1163 | { | |
1164 | struct keyring_search_context *ctx = iterator_data; | |
1165 | const struct key *key = keyring_ptr_to_key(object); | |
1166 | ||
1167 | kenter("{%d}", key->serial); | |
1168 | ||
979e0d74 DH |
1169 | /* We might get a keyring with matching index-key that is nonetheless a |
1170 | * different keyring. */ | |
46291959 | 1171 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1172 | return 0; |
1173 | ||
b2a4df20 DH |
1174 | ctx->result = ERR_PTR(-EDEADLK); |
1175 | return 1; | |
1176 | } | |
1177 | ||
1da177e4 | 1178 | /* |
973c9f4f DH |
1179 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1180 | * tree A at the topmost level (ie: as a direct child of A). | |
1181 | * | |
1182 | * Since we are adding B to A at the top level, checking for cycles should just | |
1183 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1184 | */ |
1185 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1186 | { | |
b2a4df20 | 1187 | struct keyring_search_context ctx = { |
46291959 DH |
1188 | .index_key = A->index_key, |
1189 | .match_data.raw_data = A, | |
1190 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1191 | .iterator = keyring_detect_cycle_iterator, | |
1192 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1193 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1194 | KEYRING_SEARCH_NO_CHECK_PERM | | |
1195 | KEYRING_SEARCH_DETECT_TOO_DEEP), | |
b2a4df20 | 1196 | }; |
1da177e4 | 1197 | |
76d8aeab | 1198 | rcu_read_lock(); |
b2a4df20 | 1199 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1200 | rcu_read_unlock(); |
b2a4df20 | 1201 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1202 | } |
cab8eb59 | 1203 | |
1da177e4 | 1204 | /* |
973c9f4f | 1205 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1206 | */ |
b2a4df20 DH |
1207 | int __key_link_begin(struct key *keyring, |
1208 | const struct keyring_index_key *index_key, | |
1209 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1210 | __acquires(&keyring->sem) |
423b9788 | 1211 | __acquires(&keyring_serialise_link_sem) |
1da177e4 | 1212 | { |
b2a4df20 DH |
1213 | struct assoc_array_edit *edit; |
1214 | int ret; | |
1da177e4 | 1215 | |
16feef43 | 1216 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1217 | keyring->serial, index_key->type->name, index_key->description); |
1218 | ||
1219 | BUG_ON(index_key->desc_len == 0); | |
1da177e4 | 1220 | |
1da177e4 | 1221 | if (keyring->type != &key_type_keyring) |
f70e2e06 DH |
1222 | return -ENOTDIR; |
1223 | ||
1224 | down_write(&keyring->sem); | |
1225 | ||
1226 | ret = -EKEYREVOKED; | |
1227 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
1228 | goto error_krsem; | |
1da177e4 | 1229 | |
f70e2e06 DH |
1230 | /* serialise link/link calls to prevent parallel calls causing a cycle |
1231 | * when linking two keyring in opposite orders */ | |
16feef43 | 1232 | if (index_key->type == &key_type_keyring) |
553d603c DH |
1233 | down_write(&keyring_serialise_link_sem); |
1234 | ||
b2a4df20 DH |
1235 | /* Create an edit script that will insert/replace the key in the |
1236 | * keyring tree. | |
1237 | */ | |
1238 | edit = assoc_array_insert(&keyring->keys, | |
1239 | &keyring_assoc_array_ops, | |
1240 | index_key, | |
1241 | NULL); | |
1242 | if (IS_ERR(edit)) { | |
1243 | ret = PTR_ERR(edit); | |
034faeb9 DH |
1244 | goto error_sem; |
1245 | } | |
1246 | ||
1247 | /* If we're not replacing a link in-place then we're going to need some | |
1248 | * extra quota. | |
1249 | */ | |
1250 | if (!edit->dead_leaf) { | |
1251 | ret = key_payload_reserve(keyring, | |
1252 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1253 | if (ret < 0) | |
1254 | goto error_cancel; | |
1da177e4 LT |
1255 | } |
1256 | ||
b2a4df20 | 1257 | *_edit = edit; |
f70e2e06 DH |
1258 | kleave(" = 0"); |
1259 | return 0; | |
1da177e4 | 1260 | |
034faeb9 DH |
1261 | error_cancel: |
1262 | assoc_array_cancel_edit(edit); | |
f70e2e06 | 1263 | error_sem: |
16feef43 | 1264 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1265 | up_write(&keyring_serialise_link_sem); |
1266 | error_krsem: | |
1267 | up_write(&keyring->sem); | |
1268 | kleave(" = %d", ret); | |
1269 | return ret; | |
1270 | } | |
1da177e4 | 1271 | |
f70e2e06 | 1272 | /* |
973c9f4f DH |
1273 | * Check already instantiated keys aren't going to be a problem. |
1274 | * | |
1275 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1276 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1277 | */ |
1278 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1279 | { | |
1280 | if (key->type == &key_type_keyring) | |
1281 | /* check that we aren't going to create a cycle by linking one | |
1282 | * keyring to another */ | |
1283 | return keyring_detect_cycle(keyring, key); | |
1284 | return 0; | |
1285 | } | |
1286 | ||
1287 | /* | |
973c9f4f DH |
1288 | * Link a key into to a keyring. |
1289 | * | |
1290 | * Must be called with __key_link_begin() having being called. Discards any | |
1291 | * already extant link to matching key if there is one, so that each keyring | |
1292 | * holds at most one link to any given key of a particular type+description | |
1293 | * combination. | |
f70e2e06 | 1294 | */ |
b2a4df20 | 1295 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1296 | { |
ccc3e6d9 | 1297 | __key_get(key); |
b2a4df20 DH |
1298 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1299 | assoc_array_apply_edit(*_edit); | |
1300 | *_edit = NULL; | |
f70e2e06 DH |
1301 | } |
1302 | ||
1303 | /* | |
973c9f4f DH |
1304 | * Finish linking a key into to a keyring. |
1305 | * | |
1306 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1307 | */ |
16feef43 DH |
1308 | void __key_link_end(struct key *keyring, |
1309 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1310 | struct assoc_array_edit *edit) |
f70e2e06 | 1311 | __releases(&keyring->sem) |
423b9788 | 1312 | __releases(&keyring_serialise_link_sem) |
f70e2e06 | 1313 | { |
16feef43 | 1314 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1315 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1316 | |
16feef43 | 1317 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1318 | up_write(&keyring_serialise_link_sem); |
1319 | ||
ca4da5dd CIK |
1320 | if (edit) { |
1321 | if (!edit->dead_leaf) { | |
1322 | key_payload_reserve(keyring, | |
1323 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1324 | } | |
b2a4df20 | 1325 | assoc_array_cancel_edit(edit); |
f70e2e06 DH |
1326 | } |
1327 | up_write(&keyring->sem); | |
1328 | } | |
1da177e4 | 1329 | |
5ac7eace DH |
1330 | /* |
1331 | * Check addition of keys to restricted keyrings. | |
1332 | */ | |
1333 | static int __key_link_check_restriction(struct key *keyring, struct key *key) | |
1334 | { | |
2b6aa412 | 1335 | if (!keyring->restrict_link || !keyring->restrict_link->check) |
5ac7eace | 1336 | return 0; |
2b6aa412 MM |
1337 | return keyring->restrict_link->check(keyring, key->type, &key->payload, |
1338 | keyring->restrict_link->key); | |
5ac7eace DH |
1339 | } |
1340 | ||
973c9f4f DH |
1341 | /** |
1342 | * key_link - Link a key to a keyring | |
1343 | * @keyring: The keyring to make the link in. | |
1344 | * @key: The key to link to. | |
1345 | * | |
1346 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1347 | * on that key and the key can potentially be found by searching that keyring. | |
1348 | * | |
1349 | * This function will write-lock the keyring's semaphore and will consume some | |
1350 | * of the user's key data quota to hold the link. | |
1351 | * | |
1352 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1353 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1354 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1355 | * another link or -ENOMEM if there's insufficient memory. | |
1356 | * | |
1357 | * It is assumed that the caller has checked that it is permitted for a link to | |
1358 | * be made (the keyring should have Write permission and the key Link | |
1359 | * permission). | |
1da177e4 LT |
1360 | */ |
1361 | int key_link(struct key *keyring, struct key *key) | |
1362 | { | |
b2a4df20 | 1363 | struct assoc_array_edit *edit; |
1da177e4 LT |
1364 | int ret; |
1365 | ||
fff29291 | 1366 | kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
b2a4df20 | 1367 | |
1da177e4 LT |
1368 | key_check(keyring); |
1369 | key_check(key); | |
1370 | ||
b2a4df20 | 1371 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
f70e2e06 | 1372 | if (ret == 0) { |
fff29291 | 1373 | kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
5ac7eace DH |
1374 | ret = __key_link_check_restriction(keyring, key); |
1375 | if (ret == 0) | |
1376 | ret = __key_link_check_live_key(keyring, key); | |
f70e2e06 | 1377 | if (ret == 0) |
b2a4df20 DH |
1378 | __key_link(key, &edit); |
1379 | __key_link_end(keyring, &key->index_key, edit); | |
f70e2e06 | 1380 | } |
1da177e4 | 1381 | |
fff29291 | 1382 | kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage)); |
1da177e4 | 1383 | return ret; |
f70e2e06 | 1384 | } |
1da177e4 LT |
1385 | EXPORT_SYMBOL(key_link); |
1386 | ||
973c9f4f DH |
1387 | /** |
1388 | * key_unlink - Unlink the first link to a key from a keyring. | |
1389 | * @keyring: The keyring to remove the link from. | |
1390 | * @key: The key the link is to. | |
1391 | * | |
1392 | * Remove a link from a keyring to a key. | |
1393 | * | |
1394 | * This function will write-lock the keyring's semaphore. | |
1395 | * | |
1396 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1397 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1398 | * memory. | |
1399 | * | |
1400 | * It is assumed that the caller has checked that it is permitted for a link to | |
1401 | * be removed (the keyring should have Write permission; no permissions are | |
1402 | * required on the key). | |
1da177e4 LT |
1403 | */ |
1404 | int key_unlink(struct key *keyring, struct key *key) | |
1405 | { | |
b2a4df20 DH |
1406 | struct assoc_array_edit *edit; |
1407 | int ret; | |
1da177e4 LT |
1408 | |
1409 | key_check(keyring); | |
1410 | key_check(key); | |
1411 | ||
1da177e4 | 1412 | if (keyring->type != &key_type_keyring) |
b2a4df20 | 1413 | return -ENOTDIR; |
1da177e4 LT |
1414 | |
1415 | down_write(&keyring->sem); | |
1416 | ||
b2a4df20 DH |
1417 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, |
1418 | &key->index_key); | |
1419 | if (IS_ERR(edit)) { | |
1420 | ret = PTR_ERR(edit); | |
1421 | goto error; | |
1da177e4 | 1422 | } |
1da177e4 | 1423 | ret = -ENOENT; |
b2a4df20 DH |
1424 | if (edit == NULL) |
1425 | goto error; | |
1da177e4 | 1426 | |
b2a4df20 | 1427 | assoc_array_apply_edit(edit); |
034faeb9 | 1428 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); |
1da177e4 LT |
1429 | ret = 0; |
1430 | ||
76d8aeab | 1431 | error: |
76d8aeab | 1432 | up_write(&keyring->sem); |
b2a4df20 | 1433 | return ret; |
a8b17ed0 | 1434 | } |
1da177e4 LT |
1435 | EXPORT_SYMBOL(key_unlink); |
1436 | ||
973c9f4f DH |
1437 | /** |
1438 | * keyring_clear - Clear a keyring | |
1439 | * @keyring: The keyring to clear. | |
1440 | * | |
1441 | * Clear the contents of the specified keyring. | |
1442 | * | |
1443 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1444 | */ |
1445 | int keyring_clear(struct key *keyring) | |
1446 | { | |
b2a4df20 | 1447 | struct assoc_array_edit *edit; |
76d8aeab | 1448 | int ret; |
1da177e4 | 1449 | |
b2a4df20 DH |
1450 | if (keyring->type != &key_type_keyring) |
1451 | return -ENOTDIR; | |
1da177e4 | 1452 | |
b2a4df20 | 1453 | down_write(&keyring->sem); |
1da177e4 | 1454 | |
b2a4df20 DH |
1455 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1456 | if (IS_ERR(edit)) { | |
1457 | ret = PTR_ERR(edit); | |
1458 | } else { | |
1459 | if (edit) | |
1460 | assoc_array_apply_edit(edit); | |
1461 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1462 | ret = 0; |
1463 | } | |
1464 | ||
b2a4df20 | 1465 | up_write(&keyring->sem); |
1da177e4 | 1466 | return ret; |
a8b17ed0 | 1467 | } |
1da177e4 | 1468 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1469 | |
31204ed9 | 1470 | /* |
973c9f4f DH |
1471 | * Dispose of the links from a revoked keyring. |
1472 | * | |
1473 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1474 | */ |
1475 | static void keyring_revoke(struct key *keyring) | |
1476 | { | |
b2a4df20 | 1477 | struct assoc_array_edit *edit; |
f0641cba | 1478 | |
b2a4df20 DH |
1479 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1480 | if (!IS_ERR(edit)) { | |
1481 | if (edit) | |
1482 | assoc_array_apply_edit(edit); | |
1483 | key_payload_reserve(keyring, 0); | |
1484 | } | |
1485 | } | |
31204ed9 | 1486 | |
62fe3182 | 1487 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1488 | { |
1489 | struct key *key = keyring_ptr_to_key(object); | |
1490 | time_t *limit = iterator_data; | |
31204ed9 | 1491 | |
b2a4df20 DH |
1492 | if (key_is_dead(key, *limit)) |
1493 | return false; | |
1494 | key_get(key); | |
1495 | return true; | |
a8b17ed0 | 1496 | } |
5d135440 | 1497 | |
62fe3182 DH |
1498 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1499 | { | |
1500 | const struct key *key = keyring_ptr_to_key(object); | |
1501 | time_t *limit = iterator_data; | |
1502 | ||
1503 | key_check(key); | |
1504 | return key_is_dead(key, *limit); | |
1505 | } | |
1506 | ||
5d135440 | 1507 | /* |
62fe3182 | 1508 | * Garbage collect pointers from a keyring. |
973c9f4f | 1509 | * |
62fe3182 DH |
1510 | * Not called with any locks held. The keyring's key struct will not be |
1511 | * deallocated under us as only our caller may deallocate it. | |
5d135440 DH |
1512 | */ |
1513 | void keyring_gc(struct key *keyring, time_t limit) | |
1514 | { | |
62fe3182 DH |
1515 | int result; |
1516 | ||
1517 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1518 | |
62fe3182 DH |
1519 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1520 | (1 << KEY_FLAG_REVOKED))) | |
1521 | goto dont_gc; | |
1522 | ||
1523 | /* scan the keyring looking for dead keys */ | |
1524 | rcu_read_lock(); | |
1525 | result = assoc_array_iterate(&keyring->keys, | |
1526 | keyring_gc_check_iterator, &limit); | |
1527 | rcu_read_unlock(); | |
1528 | if (result == true) | |
1529 | goto do_gc; | |
1530 | ||
1531 | dont_gc: | |
1532 | kleave(" [no gc]"); | |
1533 | return; | |
1534 | ||
1535 | do_gc: | |
5d135440 | 1536 | down_write(&keyring->sem); |
b2a4df20 | 1537 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1538 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1539 | up_write(&keyring->sem); |
62fe3182 | 1540 | kleave(" [gc]"); |
5d135440 | 1541 | } |
2b6aa412 MM |
1542 | |
1543 | /* | |
1544 | * Garbage collect restriction pointers from a keyring. | |
1545 | * | |
1546 | * Keyring restrictions are associated with a key type, and must be cleaned | |
1547 | * up if the key type is unregistered. The restriction is altered to always | |
1548 | * reject additional keys so a keyring cannot be opened up by unregistering | |
1549 | * a key type. | |
1550 | * | |
1551 | * Not called with any keyring locks held. The keyring's key struct will not | |
1552 | * be deallocated under us as only our caller may deallocate it. | |
1553 | * | |
1554 | * The caller is required to hold key_types_sem and dead_type->sem. This is | |
1555 | * fulfilled by key_gc_keytype() holding the locks on behalf of | |
1556 | * key_garbage_collector(), which it invokes on a workqueue. | |
1557 | */ | |
1558 | void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) | |
1559 | { | |
1560 | struct key_restriction *keyres; | |
1561 | ||
1562 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
1563 | ||
1564 | /* | |
1565 | * keyring->restrict_link is only assigned at key allocation time | |
1566 | * or with the key type locked, so the only values that could be | |
1567 | * concurrently assigned to keyring->restrict_link are for key | |
1568 | * types other than dead_type. Given this, it's ok to check | |
1569 | * the key type before acquiring keyring->sem. | |
1570 | */ | |
1571 | if (!dead_type || !keyring->restrict_link || | |
1572 | keyring->restrict_link->keytype != dead_type) { | |
1573 | kleave(" [no restriction gc]"); | |
1574 | return; | |
1575 | } | |
1576 | ||
1577 | /* Lock the keyring to ensure that a link is not in progress */ | |
1578 | down_write(&keyring->sem); | |
1579 | ||
1580 | keyres = keyring->restrict_link; | |
1581 | ||
1582 | keyres->check = restrict_link_reject; | |
1583 | ||
1584 | key_put(keyres->key); | |
1585 | keyres->key = NULL; | |
1586 | keyres->keytype = NULL; | |
1587 | ||
1588 | up_write(&keyring->sem); | |
1589 | ||
1590 | kleave(" [restriction gc]"); | |
1591 | } |