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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 | |
363b02da | 417 | if (key_is_positive(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 | 425 | struct keyring_read_iterator_context { |
e645016a | 426 | size_t buflen; |
b2a4df20 DH |
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}", | |
e645016a | 438 | key->type->name, key->serial, ctx->count, ctx->buflen); |
b2a4df20 | 439 | |
e645016a | 440 | if (ctx->count >= ctx->buflen) |
b2a4df20 DH |
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 | 461 | struct keyring_read_iterator_context ctx; |
3239b6f2 | 462 | long ret; |
1da177e4 | 463 | |
b2a4df20 DH |
464 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
465 | ||
466 | if (buflen & (sizeof(key_serial_t) - 1)) | |
467 | return -EINVAL; | |
468 | ||
3239b6f2 EB |
469 | /* Copy as many key IDs as fit into the buffer */ |
470 | if (buffer && buflen) { | |
471 | ctx.buffer = (key_serial_t __user *)buffer; | |
472 | ctx.buflen = buflen; | |
473 | ctx.count = 0; | |
474 | ret = assoc_array_iterate(&keyring->keys, | |
475 | keyring_read_iterator, &ctx); | |
476 | if (ret < 0) { | |
477 | kleave(" = %ld [iterate]", ret); | |
478 | return ret; | |
479 | } | |
1da177e4 LT |
480 | } |
481 | ||
3239b6f2 EB |
482 | /* Return the size of the buffer needed */ |
483 | ret = keyring->keys.nr_leaves_on_tree * sizeof(key_serial_t); | |
484 | if (ret <= buflen) | |
485 | kleave("= %ld [ok]", ret); | |
486 | else | |
487 | kleave("= %ld [buffer too small]", ret); | |
488 | return ret; | |
a8b17ed0 | 489 | } |
1da177e4 | 490 | |
1da177e4 | 491 | /* |
973c9f4f | 492 | * Allocate a keyring and link into the destination keyring. |
1da177e4 | 493 | */ |
9a56c2db | 494 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
96b5c8fe | 495 | const struct cred *cred, key_perm_t perm, |
5ac7eace | 496 | unsigned long flags, |
2b6aa412 | 497 | struct key_restriction *restrict_link, |
5ac7eace | 498 | struct key *dest) |
1da177e4 LT |
499 | { |
500 | struct key *keyring; | |
501 | int ret; | |
502 | ||
503 | keyring = key_alloc(&key_type_keyring, description, | |
5ac7eace | 504 | uid, gid, cred, perm, flags, restrict_link); |
1da177e4 | 505 | if (!IS_ERR(keyring)) { |
3e30148c | 506 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
507 | if (ret < 0) { |
508 | key_put(keyring); | |
509 | keyring = ERR_PTR(ret); | |
510 | } | |
511 | } | |
512 | ||
513 | return keyring; | |
a8b17ed0 | 514 | } |
f8aa23a5 | 515 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 516 | |
5ac7eace DH |
517 | /** |
518 | * restrict_link_reject - Give -EPERM to restrict link | |
519 | * @keyring: The keyring being added to. | |
520 | * @type: The type of key being added. | |
5ac7eace | 521 | * @payload: The payload of the key intended to be added. |
aaf66c88 | 522 | * @data: Additional data for evaluating restriction. |
5ac7eace DH |
523 | * |
524 | * Reject the addition of any links to a keyring. It can be overridden by | |
525 | * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when | |
526 | * adding a key to a keyring. | |
527 | * | |
2b6aa412 MM |
528 | * This is meant to be stored in a key_restriction structure which is passed |
529 | * in the restrict_link parameter to keyring_alloc(). | |
5ac7eace DH |
530 | */ |
531 | int restrict_link_reject(struct key *keyring, | |
532 | const struct key_type *type, | |
aaf66c88 MM |
533 | const union key_payload *payload, |
534 | struct key *restriction_key) | |
5ac7eace DH |
535 | { |
536 | return -EPERM; | |
537 | } | |
538 | ||
c06cfb08 DH |
539 | /* |
540 | * By default, we keys found by getting an exact match on their descriptions. | |
541 | */ | |
0c903ab6 DH |
542 | bool key_default_cmp(const struct key *key, |
543 | const struct key_match_data *match_data) | |
c06cfb08 DH |
544 | { |
545 | return strcmp(key->description, match_data->raw_data) == 0; | |
546 | } | |
547 | ||
b2a4df20 DH |
548 | /* |
549 | * Iteration function to consider each key found. | |
1da177e4 | 550 | */ |
b2a4df20 | 551 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 552 | { |
b2a4df20 DH |
553 | struct keyring_search_context *ctx = iterator_data; |
554 | const struct key *key = keyring_ptr_to_key(object); | |
363b02da DH |
555 | unsigned long kflags = READ_ONCE(key->flags); |
556 | short state = READ_ONCE(key->state); | |
1da177e4 | 557 | |
b2a4df20 | 558 | kenter("{%d}", key->serial); |
1da177e4 | 559 | |
b2a4df20 DH |
560 | /* ignore keys not of this type */ |
561 | if (key->type != ctx->index_key.type) { | |
562 | kleave(" = 0 [!type]"); | |
563 | return 0; | |
29db9190 | 564 | } |
1da177e4 | 565 | |
b2a4df20 DH |
566 | /* skip invalidated, revoked and expired keys */ |
567 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
074d5898 | 568 | time64_t expiry = READ_ONCE(key->expiry); |
9d6c8711 | 569 | |
b2a4df20 DH |
570 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | |
571 | (1 << KEY_FLAG_REVOKED))) { | |
572 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
573 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
574 | goto skipped; | |
575 | } | |
1da177e4 | 576 | |
074d5898 | 577 | if (expiry && ctx->now >= expiry) { |
0b0a8415 DH |
578 | if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) |
579 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
b2a4df20 DH |
580 | kleave(" = %d [expire]", ctx->skipped_ret); |
581 | goto skipped; | |
582 | } | |
583 | } | |
664cceb0 | 584 | |
b2a4df20 | 585 | /* keys that don't match */ |
46291959 | 586 | if (!ctx->match_data.cmp(key, &ctx->match_data)) { |
b2a4df20 DH |
587 | kleave(" = 0 [!match]"); |
588 | return 0; | |
589 | } | |
dceba994 | 590 | |
b2a4df20 DH |
591 | /* key must have search permissions */ |
592 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
593 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 594 | ctx->cred, KEY_NEED_SEARCH) < 0) { |
b2a4df20 DH |
595 | ctx->result = ERR_PTR(-EACCES); |
596 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
597 | goto skipped; | |
dceba994 KC |
598 | } |
599 | ||
b2a4df20 DH |
600 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
601 | /* we set a different error code if we pass a negative key */ | |
363b02da DH |
602 | if (state < 0) { |
603 | ctx->result = ERR_PTR(state); | |
b2a4df20 DH |
604 | kleave(" = %d [neg]", ctx->skipped_ret); |
605 | goto skipped; | |
606 | } | |
607 | } | |
1da177e4 | 608 | |
b2a4df20 DH |
609 | /* Found */ |
610 | ctx->result = make_key_ref(key, ctx->possessed); | |
611 | kleave(" = 1 [found]"); | |
612 | return 1; | |
1da177e4 | 613 | |
b2a4df20 DH |
614 | skipped: |
615 | return ctx->skipped_ret; | |
616 | } | |
1da177e4 | 617 | |
b2a4df20 DH |
618 | /* |
619 | * Search inside a keyring for a key. We can search by walking to it | |
620 | * directly based on its index-key or we can iterate over the entire | |
621 | * tree looking for it, based on the match function. | |
622 | */ | |
623 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
624 | { | |
46291959 | 625 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { |
b2a4df20 DH |
626 | const void *object; |
627 | ||
628 | object = assoc_array_find(&keyring->keys, | |
629 | &keyring_assoc_array_ops, | |
630 | &ctx->index_key); | |
631 | return object ? ctx->iterator(object, ctx) : 0; | |
632 | } | |
633 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
634 | } | |
1da177e4 | 635 | |
b2a4df20 DH |
636 | /* |
637 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
638 | * depth. | |
639 | */ | |
640 | static bool search_nested_keyrings(struct key *keyring, | |
641 | struct keyring_search_context *ctx) | |
642 | { | |
643 | struct { | |
644 | struct key *keyring; | |
645 | struct assoc_array_node *node; | |
646 | int slot; | |
647 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 648 | |
b2a4df20 DH |
649 | struct assoc_array_shortcut *shortcut; |
650 | struct assoc_array_node *node; | |
651 | struct assoc_array_ptr *ptr; | |
652 | struct key *key; | |
653 | int sp = 0, slot; | |
1da177e4 | 654 | |
b2a4df20 DH |
655 | kenter("{%d},{%s,%s}", |
656 | keyring->serial, | |
657 | ctx->index_key.type->name, | |
658 | ctx->index_key.description); | |
1da177e4 | 659 | |
054f6180 DH |
660 | #define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK) |
661 | BUG_ON((ctx->flags & STATE_CHECKS) == 0 || | |
662 | (ctx->flags & STATE_CHECKS) == STATE_CHECKS); | |
663 | ||
b2a4df20 DH |
664 | if (ctx->index_key.description) |
665 | ctx->index_key.desc_len = strlen(ctx->index_key.description); | |
1da177e4 | 666 | |
b2a4df20 DH |
667 | /* Check to see if this top-level keyring is what we are looking for |
668 | * and whether it is valid or not. | |
669 | */ | |
46291959 | 670 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || |
b2a4df20 DH |
671 | keyring_compare_object(keyring, &ctx->index_key)) { |
672 | ctx->skipped_ret = 2; | |
b2a4df20 DH |
673 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { |
674 | case 1: | |
78b7280c | 675 | goto found; |
b2a4df20 DH |
676 | case 2: |
677 | return false; | |
678 | default: | |
679 | break; | |
1da177e4 | 680 | } |
b2a4df20 | 681 | } |
1da177e4 | 682 | |
b2a4df20 | 683 | ctx->skipped_ret = 0; |
b2a4df20 DH |
684 | |
685 | /* Start processing a new keyring */ | |
686 | descend_to_keyring: | |
687 | kdebug("descend to %d", keyring->serial); | |
688 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
689 | (1 << KEY_FLAG_REVOKED))) | |
690 | goto not_this_keyring; | |
691 | ||
692 | /* Search through the keys in this keyring before its searching its | |
693 | * subtrees. | |
694 | */ | |
695 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 696 | goto found; |
1da177e4 | 697 | |
b2a4df20 DH |
698 | /* Then manually iterate through the keyrings nested in this one. |
699 | * | |
700 | * Start from the root node of the index tree. Because of the way the | |
701 | * hash function has been set up, keyrings cluster on the leftmost | |
702 | * branch of the root node (root slot 0) or in the root node itself. | |
703 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
704 | * slots 1-15). | |
705 | */ | |
381f20fc | 706 | ptr = READ_ONCE(keyring->keys.root); |
b2a4df20 DH |
707 | if (!ptr) |
708 | goto not_this_keyring; | |
1da177e4 | 709 | |
b2a4df20 DH |
710 | if (assoc_array_ptr_is_shortcut(ptr)) { |
711 | /* If the root is a shortcut, either the keyring only contains | |
712 | * keyring pointers (everything clusters behind root slot 0) or | |
713 | * doesn't contain any keyring pointers. | |
1da177e4 | 714 | */ |
b2a4df20 | 715 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
b2a4df20 DH |
716 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) |
717 | goto not_this_keyring; | |
718 | ||
381f20fc | 719 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 DH |
720 | node = assoc_array_ptr_to_node(ptr); |
721 | goto begin_node; | |
722 | } | |
723 | ||
724 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
725 | ptr = node->slots[0]; |
726 | if (!assoc_array_ptr_is_meta(ptr)) | |
727 | goto begin_node; | |
728 | ||
729 | descend_to_node: | |
730 | /* Descend to a more distal node in this keyring's content tree and go | |
731 | * through that. | |
732 | */ | |
733 | kdebug("descend"); | |
734 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
735 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 736 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 | 737 | BUG_ON(!assoc_array_ptr_is_node(ptr)); |
b2a4df20 | 738 | } |
9c5e45df | 739 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
740 | |
741 | begin_node: | |
742 | kdebug("begin_node"); | |
b2a4df20 DH |
743 | slot = 0; |
744 | ascend_to_node: | |
745 | /* Go through the slots in a node */ | |
746 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
381f20fc | 747 | ptr = READ_ONCE(node->slots[slot]); |
b2a4df20 DH |
748 | |
749 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
750 | goto descend_to_node; | |
751 | ||
752 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 753 | continue; |
1da177e4 | 754 | |
b2a4df20 DH |
755 | key = keyring_ptr_to_key(ptr); |
756 | ||
757 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
758 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
759 | ctx->result = ERR_PTR(-ELOOP); | |
760 | return false; | |
761 | } | |
762 | goto not_this_keyring; | |
763 | } | |
764 | ||
765 | /* Search a nested keyring */ | |
766 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
767 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 768 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 769 | continue; |
1da177e4 LT |
770 | |
771 | /* stack the current position */ | |
31d5a79d | 772 | stack[sp].keyring = keyring; |
b2a4df20 DH |
773 | stack[sp].node = node; |
774 | stack[sp].slot = slot; | |
1da177e4 LT |
775 | sp++; |
776 | ||
777 | /* begin again with the new keyring */ | |
778 | keyring = key; | |
b2a4df20 DH |
779 | goto descend_to_keyring; |
780 | } | |
781 | ||
782 | /* We've dealt with all the slots in the current node, so now we need | |
783 | * to ascend to the parent and continue processing there. | |
784 | */ | |
381f20fc | 785 | ptr = READ_ONCE(node->back_pointer); |
b2a4df20 DH |
786 | slot = node->parent_slot; |
787 | ||
788 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
789 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 790 | ptr = READ_ONCE(shortcut->back_pointer); |
b2a4df20 DH |
791 | slot = shortcut->parent_slot; |
792 | } | |
793 | if (!ptr) | |
794 | goto not_this_keyring; | |
795 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
796 | slot++; |
797 | ||
798 | /* If we've ascended to the root (zero backpointer), we must have just | |
799 | * finished processing the leftmost branch rather than the root slots - | |
800 | * so there can't be any more keyrings for us to find. | |
801 | */ | |
802 | if (node->back_pointer) { | |
803 | kdebug("ascend %d", slot); | |
804 | goto ascend_to_node; | |
1da177e4 LT |
805 | } |
806 | ||
b2a4df20 DH |
807 | /* The keyring we're looking at was disqualified or didn't contain a |
808 | * matching key. | |
809 | */ | |
664cceb0 | 810 | not_this_keyring: |
b2a4df20 DH |
811 | kdebug("not_this_keyring %d", sp); |
812 | if (sp <= 0) { | |
813 | kleave(" = false"); | |
814 | return false; | |
1da177e4 LT |
815 | } |
816 | ||
b2a4df20 DH |
817 | /* Resume the processing of a keyring higher up in the tree */ |
818 | sp--; | |
819 | keyring = stack[sp].keyring; | |
820 | node = stack[sp].node; | |
821 | slot = stack[sp].slot + 1; | |
822 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
823 | goto ascend_to_node; | |
1da177e4 | 824 | |
b2a4df20 | 825 | /* We found a viable match */ |
664cceb0 | 826 | found: |
b2a4df20 | 827 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 828 | key_check(key); |
b2a4df20 | 829 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
074d5898 BW |
830 | key->last_used_at = ctx->now; |
831 | keyring->last_used_at = ctx->now; | |
b2a4df20 | 832 | while (sp > 0) |
074d5898 | 833 | stack[--sp].keyring->last_used_at = ctx->now; |
b2a4df20 DH |
834 | } |
835 | kleave(" = true"); | |
836 | return true; | |
837 | } | |
838 | ||
839 | /** | |
840 | * keyring_search_aux - Search a keyring tree for a key matching some criteria | |
841 | * @keyring_ref: A pointer to the keyring with possession indicator. | |
842 | * @ctx: The keyring search context. | |
843 | * | |
844 | * Search the supplied keyring tree for a key that matches the criteria given. | |
845 | * The root keyring and any linked keyrings must grant Search permission to the | |
846 | * caller to be searchable and keys can only be found if they too grant Search | |
847 | * to the caller. The possession flag on the root keyring pointer controls use | |
848 | * of the possessor bits in permissions checking of the entire tree. In | |
849 | * addition, the LSM gets to forbid keyring searches and key matches. | |
850 | * | |
851 | * The search is performed as a breadth-then-depth search up to the prescribed | |
852 | * limit (KEYRING_SEARCH_MAX_DEPTH). | |
853 | * | |
854 | * Keys are matched to the type provided and are then filtered by the match | |
855 | * function, which is given the description to use in any way it sees fit. The | |
856 | * match function may use any attributes of a key that it wishes to to | |
857 | * determine the match. Normally the match function from the key type would be | |
858 | * used. | |
859 | * | |
860 | * RCU can be used to prevent the keyring key lists from disappearing without | |
861 | * the need to take lots of locks. | |
862 | * | |
863 | * Returns a pointer to the found key and increments the key usage count if | |
864 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
865 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
866 | * specified keyring wasn't a keyring. | |
867 | * | |
868 | * In the case of a successful return, the possession attribute from | |
869 | * @keyring_ref is propagated to the returned key reference. | |
870 | */ | |
871 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, | |
872 | struct keyring_search_context *ctx) | |
873 | { | |
874 | struct key *keyring; | |
875 | long err; | |
876 | ||
877 | ctx->iterator = keyring_search_iterator; | |
878 | ctx->possessed = is_key_possessed(keyring_ref); | |
879 | ctx->result = ERR_PTR(-EAGAIN); | |
880 | ||
881 | keyring = key_ref_to_ptr(keyring_ref); | |
882 | key_check(keyring); | |
883 | ||
884 | if (keyring->type != &key_type_keyring) | |
885 | return ERR_PTR(-ENOTDIR); | |
886 | ||
887 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 888 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
889 | if (err < 0) |
890 | return ERR_PTR(err); | |
891 | } | |
892 | ||
893 | rcu_read_lock(); | |
074d5898 | 894 | ctx->now = ktime_get_real_seconds(); |
b2a4df20 DH |
895 | if (search_nested_keyrings(keyring, ctx)) |
896 | __key_get(key_ref_to_ptr(ctx->result)); | |
76d8aeab | 897 | rcu_read_unlock(); |
b2a4df20 | 898 | return ctx->result; |
a8b17ed0 | 899 | } |
1da177e4 | 900 | |
973c9f4f DH |
901 | /** |
902 | * keyring_search - Search the supplied keyring tree for a matching key | |
903 | * @keyring: The root of the keyring tree to be searched. | |
904 | * @type: The type of keyring we want to find. | |
905 | * @description: The name of the keyring we want to find. | |
906 | * | |
907 | * As keyring_search_aux() above, but using the current task's credentials and | |
b2a4df20 | 908 | * type's default matching function and preferred search method. |
1da177e4 | 909 | */ |
664cceb0 DH |
910 | key_ref_t keyring_search(key_ref_t keyring, |
911 | struct key_type *type, | |
912 | const char *description) | |
1da177e4 | 913 | { |
4bdf0bc3 DH |
914 | struct keyring_search_context ctx = { |
915 | .index_key.type = type, | |
916 | .index_key.description = description, | |
917 | .cred = current_cred(), | |
c06cfb08 | 918 | .match_data.cmp = key_default_cmp, |
46291959 DH |
919 | .match_data.raw_data = description, |
920 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
921 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 922 | }; |
46291959 DH |
923 | key_ref_t key; |
924 | int ret; | |
4bdf0bc3 | 925 | |
46291959 DH |
926 | if (type->match_preparse) { |
927 | ret = type->match_preparse(&ctx.match_data); | |
928 | if (ret < 0) | |
929 | return ERR_PTR(ret); | |
930 | } | |
931 | ||
932 | key = keyring_search_aux(keyring, &ctx); | |
933 | ||
934 | if (type->match_free) | |
935 | type->match_free(&ctx.match_data); | |
936 | return key; | |
a8b17ed0 | 937 | } |
1da177e4 LT |
938 | EXPORT_SYMBOL(keyring_search); |
939 | ||
6563c91f MM |
940 | static struct key_restriction *keyring_restriction_alloc( |
941 | key_restrict_link_func_t check) | |
942 | { | |
943 | struct key_restriction *keyres = | |
944 | kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
945 | ||
946 | if (!keyres) | |
947 | return ERR_PTR(-ENOMEM); | |
948 | ||
949 | keyres->check = check; | |
950 | ||
951 | return keyres; | |
952 | } | |
953 | ||
954 | /* | |
955 | * Semaphore to serialise restriction setup to prevent reference count | |
956 | * cycles through restriction key pointers. | |
957 | */ | |
958 | static DECLARE_RWSEM(keyring_serialise_restrict_sem); | |
959 | ||
960 | /* | |
961 | * Check for restriction cycles that would prevent keyring garbage collection. | |
962 | * keyring_serialise_restrict_sem must be held. | |
963 | */ | |
964 | static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, | |
965 | struct key_restriction *keyres) | |
966 | { | |
967 | while (keyres && keyres->key && | |
968 | keyres->key->type == &key_type_keyring) { | |
969 | if (keyres->key == dest_keyring) | |
970 | return true; | |
971 | ||
972 | keyres = keyres->key->restrict_link; | |
973 | } | |
974 | ||
975 | return false; | |
976 | } | |
977 | ||
978 | /** | |
979 | * keyring_restrict - Look up and apply a restriction to a keyring | |
980 | * | |
981 | * @keyring: The keyring to be restricted | |
982 | * @restriction: The restriction options to apply to the keyring | |
983 | */ | |
984 | int keyring_restrict(key_ref_t keyring_ref, const char *type, | |
985 | const char *restriction) | |
986 | { | |
987 | struct key *keyring; | |
988 | struct key_type *restrict_type = NULL; | |
989 | struct key_restriction *restrict_link; | |
990 | int ret = 0; | |
991 | ||
992 | keyring = key_ref_to_ptr(keyring_ref); | |
993 | key_check(keyring); | |
994 | ||
995 | if (keyring->type != &key_type_keyring) | |
996 | return -ENOTDIR; | |
997 | ||
998 | if (!type) { | |
999 | restrict_link = keyring_restriction_alloc(restrict_link_reject); | |
1000 | } else { | |
1001 | restrict_type = key_type_lookup(type); | |
1002 | ||
1003 | if (IS_ERR(restrict_type)) | |
1004 | return PTR_ERR(restrict_type); | |
1005 | ||
1006 | if (!restrict_type->lookup_restriction) { | |
1007 | ret = -ENOENT; | |
1008 | goto error; | |
1009 | } | |
1010 | ||
1011 | restrict_link = restrict_type->lookup_restriction(restriction); | |
1012 | } | |
1013 | ||
1014 | if (IS_ERR(restrict_link)) { | |
1015 | ret = PTR_ERR(restrict_link); | |
1016 | goto error; | |
1017 | } | |
1018 | ||
1019 | down_write(&keyring->sem); | |
1020 | down_write(&keyring_serialise_restrict_sem); | |
1021 | ||
1022 | if (keyring->restrict_link) | |
1023 | ret = -EEXIST; | |
1024 | else if (keyring_detect_restriction_cycle(keyring, restrict_link)) | |
1025 | ret = -EDEADLK; | |
1026 | else | |
1027 | keyring->restrict_link = restrict_link; | |
1028 | ||
1029 | up_write(&keyring_serialise_restrict_sem); | |
1030 | up_write(&keyring->sem); | |
1031 | ||
1032 | if (ret < 0) { | |
1033 | key_put(restrict_link->key); | |
1034 | kfree(restrict_link); | |
1035 | } | |
1036 | ||
1037 | error: | |
1038 | if (restrict_type) | |
1039 | key_type_put(restrict_type); | |
1040 | ||
1041 | return ret; | |
1042 | } | |
1043 | EXPORT_SYMBOL(keyring_restrict); | |
1044 | ||
1da177e4 | 1045 | /* |
b2a4df20 | 1046 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
1047 | * |
1048 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
1049 | * permission is granted to modify the keyring as no check is made here. The |
1050 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
1051 | * |
1052 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
1053 | * successful and returns NULL if not found. Revoked and invalidated keys are |
1054 | * skipped over. | |
973c9f4f DH |
1055 | * |
1056 | * If successful, the possession indicator is propagated from the keyring ref | |
1057 | * to the returned key reference. | |
1da177e4 | 1058 | */ |
b2a4df20 DH |
1059 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
1060 | const struct keyring_index_key *index_key) | |
1da177e4 | 1061 | { |
664cceb0 | 1062 | struct key *keyring, *key; |
b2a4df20 | 1063 | const void *object; |
1da177e4 | 1064 | |
664cceb0 | 1065 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 1066 | |
b2a4df20 DH |
1067 | kenter("{%d},{%s,%s}", |
1068 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 1069 | |
b2a4df20 DH |
1070 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
1071 | index_key); | |
1da177e4 | 1072 | |
b2a4df20 DH |
1073 | if (object) |
1074 | goto found; | |
1075 | ||
1076 | kleave(" = NULL"); | |
1077 | return NULL; | |
1da177e4 | 1078 | |
c5b60b5e | 1079 | found: |
b2a4df20 DH |
1080 | key = keyring_ptr_to_key(object); |
1081 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
1082 | (1 << KEY_FLAG_REVOKED))) { | |
1083 | kleave(" = NULL [x]"); | |
1084 | return NULL; | |
1085 | } | |
ccc3e6d9 | 1086 | __key_get(key); |
b2a4df20 DH |
1087 | kleave(" = {%d}", key->serial); |
1088 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 1089 | } |
1da177e4 | 1090 | |
1da177e4 | 1091 | /* |
973c9f4f DH |
1092 | * Find a keyring with the specified name. |
1093 | * | |
237bbd29 EB |
1094 | * Only keyrings that have nonzero refcount, are not revoked, and are owned by a |
1095 | * user in the current user namespace are considered. If @uid_keyring is %true, | |
1096 | * the keyring additionally must have been allocated as a user or user session | |
1097 | * keyring; otherwise, it must grant Search permission directly to the caller. | |
973c9f4f DH |
1098 | * |
1099 | * Returns a pointer to the keyring with the keyring's refcount having being | |
1100 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 1101 | */ |
237bbd29 | 1102 | struct key *find_keyring_by_name(const char *name, bool uid_keyring) |
1da177e4 LT |
1103 | { |
1104 | struct key *keyring; | |
1105 | int bucket; | |
1106 | ||
1da177e4 | 1107 | if (!name) |
cea7daa3 | 1108 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
1109 | |
1110 | bucket = keyring_hash(name); | |
1111 | ||
1112 | read_lock(&keyring_name_lock); | |
1113 | ||
1114 | if (keyring_name_hash[bucket].next) { | |
1115 | /* search this hash bucket for a keyring with a matching name | |
1116 | * that's readable and that hasn't been revoked */ | |
1117 | list_for_each_entry(keyring, | |
1118 | &keyring_name_hash[bucket], | |
146aa8b1 | 1119 | name_link |
1da177e4 | 1120 | ) { |
9a56c2db | 1121 | if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) |
2ea190d0 SH |
1122 | continue; |
1123 | ||
76d8aeab | 1124 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1da177e4 LT |
1125 | continue; |
1126 | ||
1127 | if (strcmp(keyring->description, name) != 0) | |
1128 | continue; | |
1129 | ||
237bbd29 EB |
1130 | if (uid_keyring) { |
1131 | if (!test_bit(KEY_FLAG_UID_KEYRING, | |
1132 | &keyring->flags)) | |
1133 | continue; | |
1134 | } else { | |
1135 | if (key_permission(make_key_ref(keyring, 0), | |
1136 | KEY_NEED_SEARCH) < 0) | |
1137 | continue; | |
1138 | } | |
1da177e4 | 1139 | |
cea7daa3 TO |
1140 | /* we've got a match but we might end up racing with |
1141 | * key_cleanup() if the keyring is currently 'dead' | |
1142 | * (ie. it has a zero usage count) */ | |
fff29291 | 1143 | if (!refcount_inc_not_zero(&keyring->usage)) |
cea7daa3 | 1144 | continue; |
074d5898 | 1145 | keyring->last_used_at = ktime_get_real_seconds(); |
cea7daa3 | 1146 | goto out; |
1da177e4 LT |
1147 | } |
1148 | } | |
1149 | ||
1da177e4 | 1150 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1151 | out: |
1152 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1153 | return keyring; |
a8b17ed0 | 1154 | } |
1da177e4 | 1155 | |
b2a4df20 DH |
1156 | static int keyring_detect_cycle_iterator(const void *object, |
1157 | void *iterator_data) | |
1158 | { | |
1159 | struct keyring_search_context *ctx = iterator_data; | |
1160 | const struct key *key = keyring_ptr_to_key(object); | |
1161 | ||
1162 | kenter("{%d}", key->serial); | |
1163 | ||
979e0d74 DH |
1164 | /* We might get a keyring with matching index-key that is nonetheless a |
1165 | * different keyring. */ | |
46291959 | 1166 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1167 | return 0; |
1168 | ||
b2a4df20 DH |
1169 | ctx->result = ERR_PTR(-EDEADLK); |
1170 | return 1; | |
1171 | } | |
1172 | ||
1da177e4 | 1173 | /* |
973c9f4f DH |
1174 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1175 | * tree A at the topmost level (ie: as a direct child of A). | |
1176 | * | |
1177 | * Since we are adding B to A at the top level, checking for cycles should just | |
1178 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1179 | */ |
1180 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1181 | { | |
b2a4df20 | 1182 | struct keyring_search_context ctx = { |
46291959 DH |
1183 | .index_key = A->index_key, |
1184 | .match_data.raw_data = A, | |
1185 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1186 | .iterator = keyring_detect_cycle_iterator, | |
1187 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1188 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1189 | KEYRING_SEARCH_NO_CHECK_PERM | | |
1190 | KEYRING_SEARCH_DETECT_TOO_DEEP), | |
b2a4df20 | 1191 | }; |
1da177e4 | 1192 | |
76d8aeab | 1193 | rcu_read_lock(); |
b2a4df20 | 1194 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1195 | rcu_read_unlock(); |
b2a4df20 | 1196 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1197 | } |
cab8eb59 | 1198 | |
1da177e4 | 1199 | /* |
973c9f4f | 1200 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1201 | */ |
b2a4df20 DH |
1202 | int __key_link_begin(struct key *keyring, |
1203 | const struct keyring_index_key *index_key, | |
1204 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1205 | __acquires(&keyring->sem) |
423b9788 | 1206 | __acquires(&keyring_serialise_link_sem) |
1da177e4 | 1207 | { |
b2a4df20 DH |
1208 | struct assoc_array_edit *edit; |
1209 | int ret; | |
1da177e4 | 1210 | |
16feef43 | 1211 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1212 | keyring->serial, index_key->type->name, index_key->description); |
1213 | ||
1214 | BUG_ON(index_key->desc_len == 0); | |
1da177e4 | 1215 | |
1da177e4 | 1216 | if (keyring->type != &key_type_keyring) |
f70e2e06 DH |
1217 | return -ENOTDIR; |
1218 | ||
1219 | down_write(&keyring->sem); | |
1220 | ||
1221 | ret = -EKEYREVOKED; | |
1222 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
1223 | goto error_krsem; | |
1da177e4 | 1224 | |
f70e2e06 DH |
1225 | /* serialise link/link calls to prevent parallel calls causing a cycle |
1226 | * when linking two keyring in opposite orders */ | |
16feef43 | 1227 | if (index_key->type == &key_type_keyring) |
553d603c DH |
1228 | down_write(&keyring_serialise_link_sem); |
1229 | ||
b2a4df20 DH |
1230 | /* Create an edit script that will insert/replace the key in the |
1231 | * keyring tree. | |
1232 | */ | |
1233 | edit = assoc_array_insert(&keyring->keys, | |
1234 | &keyring_assoc_array_ops, | |
1235 | index_key, | |
1236 | NULL); | |
1237 | if (IS_ERR(edit)) { | |
1238 | ret = PTR_ERR(edit); | |
034faeb9 DH |
1239 | goto error_sem; |
1240 | } | |
1241 | ||
1242 | /* If we're not replacing a link in-place then we're going to need some | |
1243 | * extra quota. | |
1244 | */ | |
1245 | if (!edit->dead_leaf) { | |
1246 | ret = key_payload_reserve(keyring, | |
1247 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1248 | if (ret < 0) | |
1249 | goto error_cancel; | |
1da177e4 LT |
1250 | } |
1251 | ||
b2a4df20 | 1252 | *_edit = edit; |
f70e2e06 DH |
1253 | kleave(" = 0"); |
1254 | return 0; | |
1da177e4 | 1255 | |
034faeb9 DH |
1256 | error_cancel: |
1257 | assoc_array_cancel_edit(edit); | |
f70e2e06 | 1258 | error_sem: |
16feef43 | 1259 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1260 | up_write(&keyring_serialise_link_sem); |
1261 | error_krsem: | |
1262 | up_write(&keyring->sem); | |
1263 | kleave(" = %d", ret); | |
1264 | return ret; | |
1265 | } | |
1da177e4 | 1266 | |
f70e2e06 | 1267 | /* |
973c9f4f DH |
1268 | * Check already instantiated keys aren't going to be a problem. |
1269 | * | |
1270 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1271 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1272 | */ |
1273 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1274 | { | |
1275 | if (key->type == &key_type_keyring) | |
1276 | /* check that we aren't going to create a cycle by linking one | |
1277 | * keyring to another */ | |
1278 | return keyring_detect_cycle(keyring, key); | |
1279 | return 0; | |
1280 | } | |
1281 | ||
1282 | /* | |
973c9f4f DH |
1283 | * Link a key into to a keyring. |
1284 | * | |
1285 | * Must be called with __key_link_begin() having being called. Discards any | |
1286 | * already extant link to matching key if there is one, so that each keyring | |
1287 | * holds at most one link to any given key of a particular type+description | |
1288 | * combination. | |
f70e2e06 | 1289 | */ |
b2a4df20 | 1290 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1291 | { |
ccc3e6d9 | 1292 | __key_get(key); |
b2a4df20 DH |
1293 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1294 | assoc_array_apply_edit(*_edit); | |
1295 | *_edit = NULL; | |
f70e2e06 DH |
1296 | } |
1297 | ||
1298 | /* | |
973c9f4f DH |
1299 | * Finish linking a key into to a keyring. |
1300 | * | |
1301 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1302 | */ |
16feef43 DH |
1303 | void __key_link_end(struct key *keyring, |
1304 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1305 | struct assoc_array_edit *edit) |
f70e2e06 | 1306 | __releases(&keyring->sem) |
423b9788 | 1307 | __releases(&keyring_serialise_link_sem) |
f70e2e06 | 1308 | { |
16feef43 | 1309 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1310 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1311 | |
16feef43 | 1312 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1313 | up_write(&keyring_serialise_link_sem); |
1314 | ||
ca4da5dd CIK |
1315 | if (edit) { |
1316 | if (!edit->dead_leaf) { | |
1317 | key_payload_reserve(keyring, | |
1318 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1319 | } | |
b2a4df20 | 1320 | assoc_array_cancel_edit(edit); |
f70e2e06 DH |
1321 | } |
1322 | up_write(&keyring->sem); | |
1323 | } | |
1da177e4 | 1324 | |
5ac7eace DH |
1325 | /* |
1326 | * Check addition of keys to restricted keyrings. | |
1327 | */ | |
1328 | static int __key_link_check_restriction(struct key *keyring, struct key *key) | |
1329 | { | |
2b6aa412 | 1330 | if (!keyring->restrict_link || !keyring->restrict_link->check) |
5ac7eace | 1331 | return 0; |
2b6aa412 MM |
1332 | return keyring->restrict_link->check(keyring, key->type, &key->payload, |
1333 | keyring->restrict_link->key); | |
5ac7eace DH |
1334 | } |
1335 | ||
973c9f4f DH |
1336 | /** |
1337 | * key_link - Link a key to a keyring | |
1338 | * @keyring: The keyring to make the link in. | |
1339 | * @key: The key to link to. | |
1340 | * | |
1341 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1342 | * on that key and the key can potentially be found by searching that keyring. | |
1343 | * | |
1344 | * This function will write-lock the keyring's semaphore and will consume some | |
1345 | * of the user's key data quota to hold the link. | |
1346 | * | |
1347 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1348 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1349 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1350 | * another link or -ENOMEM if there's insufficient memory. | |
1351 | * | |
1352 | * It is assumed that the caller has checked that it is permitted for a link to | |
1353 | * be made (the keyring should have Write permission and the key Link | |
1354 | * permission). | |
1da177e4 LT |
1355 | */ |
1356 | int key_link(struct key *keyring, struct key *key) | |
1357 | { | |
b2a4df20 | 1358 | struct assoc_array_edit *edit; |
1da177e4 LT |
1359 | int ret; |
1360 | ||
fff29291 | 1361 | kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
b2a4df20 | 1362 | |
1da177e4 LT |
1363 | key_check(keyring); |
1364 | key_check(key); | |
1365 | ||
b2a4df20 | 1366 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
f70e2e06 | 1367 | if (ret == 0) { |
fff29291 | 1368 | kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
5ac7eace DH |
1369 | ret = __key_link_check_restriction(keyring, key); |
1370 | if (ret == 0) | |
1371 | ret = __key_link_check_live_key(keyring, key); | |
f70e2e06 | 1372 | if (ret == 0) |
b2a4df20 DH |
1373 | __key_link(key, &edit); |
1374 | __key_link_end(keyring, &key->index_key, edit); | |
f70e2e06 | 1375 | } |
1da177e4 | 1376 | |
fff29291 | 1377 | kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage)); |
1da177e4 | 1378 | return ret; |
f70e2e06 | 1379 | } |
1da177e4 LT |
1380 | EXPORT_SYMBOL(key_link); |
1381 | ||
973c9f4f DH |
1382 | /** |
1383 | * key_unlink - Unlink the first link to a key from a keyring. | |
1384 | * @keyring: The keyring to remove the link from. | |
1385 | * @key: The key the link is to. | |
1386 | * | |
1387 | * Remove a link from a keyring to a key. | |
1388 | * | |
1389 | * This function will write-lock the keyring's semaphore. | |
1390 | * | |
1391 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1392 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1393 | * memory. | |
1394 | * | |
1395 | * It is assumed that the caller has checked that it is permitted for a link to | |
1396 | * be removed (the keyring should have Write permission; no permissions are | |
1397 | * required on the key). | |
1da177e4 LT |
1398 | */ |
1399 | int key_unlink(struct key *keyring, struct key *key) | |
1400 | { | |
b2a4df20 DH |
1401 | struct assoc_array_edit *edit; |
1402 | int ret; | |
1da177e4 LT |
1403 | |
1404 | key_check(keyring); | |
1405 | key_check(key); | |
1406 | ||
1da177e4 | 1407 | if (keyring->type != &key_type_keyring) |
b2a4df20 | 1408 | return -ENOTDIR; |
1da177e4 LT |
1409 | |
1410 | down_write(&keyring->sem); | |
1411 | ||
b2a4df20 DH |
1412 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, |
1413 | &key->index_key); | |
1414 | if (IS_ERR(edit)) { | |
1415 | ret = PTR_ERR(edit); | |
1416 | goto error; | |
1da177e4 | 1417 | } |
1da177e4 | 1418 | ret = -ENOENT; |
b2a4df20 DH |
1419 | if (edit == NULL) |
1420 | goto error; | |
1da177e4 | 1421 | |
b2a4df20 | 1422 | assoc_array_apply_edit(edit); |
034faeb9 | 1423 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); |
1da177e4 LT |
1424 | ret = 0; |
1425 | ||
76d8aeab | 1426 | error: |
76d8aeab | 1427 | up_write(&keyring->sem); |
b2a4df20 | 1428 | return ret; |
a8b17ed0 | 1429 | } |
1da177e4 LT |
1430 | EXPORT_SYMBOL(key_unlink); |
1431 | ||
973c9f4f DH |
1432 | /** |
1433 | * keyring_clear - Clear a keyring | |
1434 | * @keyring: The keyring to clear. | |
1435 | * | |
1436 | * Clear the contents of the specified keyring. | |
1437 | * | |
1438 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1439 | */ |
1440 | int keyring_clear(struct key *keyring) | |
1441 | { | |
b2a4df20 | 1442 | struct assoc_array_edit *edit; |
76d8aeab | 1443 | int ret; |
1da177e4 | 1444 | |
b2a4df20 DH |
1445 | if (keyring->type != &key_type_keyring) |
1446 | return -ENOTDIR; | |
1da177e4 | 1447 | |
b2a4df20 | 1448 | down_write(&keyring->sem); |
1da177e4 | 1449 | |
b2a4df20 DH |
1450 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1451 | if (IS_ERR(edit)) { | |
1452 | ret = PTR_ERR(edit); | |
1453 | } else { | |
1454 | if (edit) | |
1455 | assoc_array_apply_edit(edit); | |
1456 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1457 | ret = 0; |
1458 | } | |
1459 | ||
b2a4df20 | 1460 | up_write(&keyring->sem); |
1da177e4 | 1461 | return ret; |
a8b17ed0 | 1462 | } |
1da177e4 | 1463 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1464 | |
31204ed9 | 1465 | /* |
973c9f4f DH |
1466 | * Dispose of the links from a revoked keyring. |
1467 | * | |
1468 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1469 | */ |
1470 | static void keyring_revoke(struct key *keyring) | |
1471 | { | |
b2a4df20 | 1472 | struct assoc_array_edit *edit; |
f0641cba | 1473 | |
b2a4df20 DH |
1474 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1475 | if (!IS_ERR(edit)) { | |
1476 | if (edit) | |
1477 | assoc_array_apply_edit(edit); | |
1478 | key_payload_reserve(keyring, 0); | |
1479 | } | |
1480 | } | |
31204ed9 | 1481 | |
62fe3182 | 1482 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1483 | { |
1484 | struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1485 | time64_t *limit = iterator_data; |
31204ed9 | 1486 | |
b2a4df20 DH |
1487 | if (key_is_dead(key, *limit)) |
1488 | return false; | |
1489 | key_get(key); | |
1490 | return true; | |
a8b17ed0 | 1491 | } |
5d135440 | 1492 | |
62fe3182 DH |
1493 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1494 | { | |
1495 | const struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1496 | time64_t *limit = iterator_data; |
62fe3182 DH |
1497 | |
1498 | key_check(key); | |
1499 | return key_is_dead(key, *limit); | |
1500 | } | |
1501 | ||
5d135440 | 1502 | /* |
62fe3182 | 1503 | * Garbage collect pointers from a keyring. |
973c9f4f | 1504 | * |
62fe3182 DH |
1505 | * Not called with any locks held. The keyring's key struct will not be |
1506 | * deallocated under us as only our caller may deallocate it. | |
5d135440 | 1507 | */ |
074d5898 | 1508 | void keyring_gc(struct key *keyring, time64_t limit) |
5d135440 | 1509 | { |
62fe3182 DH |
1510 | int result; |
1511 | ||
1512 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1513 | |
62fe3182 DH |
1514 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1515 | (1 << KEY_FLAG_REVOKED))) | |
1516 | goto dont_gc; | |
1517 | ||
1518 | /* scan the keyring looking for dead keys */ | |
1519 | rcu_read_lock(); | |
1520 | result = assoc_array_iterate(&keyring->keys, | |
1521 | keyring_gc_check_iterator, &limit); | |
1522 | rcu_read_unlock(); | |
1523 | if (result == true) | |
1524 | goto do_gc; | |
1525 | ||
1526 | dont_gc: | |
1527 | kleave(" [no gc]"); | |
1528 | return; | |
1529 | ||
1530 | do_gc: | |
5d135440 | 1531 | down_write(&keyring->sem); |
b2a4df20 | 1532 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1533 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1534 | up_write(&keyring->sem); |
62fe3182 | 1535 | kleave(" [gc]"); |
5d135440 | 1536 | } |
2b6aa412 MM |
1537 | |
1538 | /* | |
1539 | * Garbage collect restriction pointers from a keyring. | |
1540 | * | |
1541 | * Keyring restrictions are associated with a key type, and must be cleaned | |
1542 | * up if the key type is unregistered. The restriction is altered to always | |
1543 | * reject additional keys so a keyring cannot be opened up by unregistering | |
1544 | * a key type. | |
1545 | * | |
1546 | * Not called with any keyring locks held. The keyring's key struct will not | |
1547 | * be deallocated under us as only our caller may deallocate it. | |
1548 | * | |
1549 | * The caller is required to hold key_types_sem and dead_type->sem. This is | |
1550 | * fulfilled by key_gc_keytype() holding the locks on behalf of | |
1551 | * key_garbage_collector(), which it invokes on a workqueue. | |
1552 | */ | |
1553 | void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) | |
1554 | { | |
1555 | struct key_restriction *keyres; | |
1556 | ||
1557 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
1558 | ||
1559 | /* | |
1560 | * keyring->restrict_link is only assigned at key allocation time | |
1561 | * or with the key type locked, so the only values that could be | |
1562 | * concurrently assigned to keyring->restrict_link are for key | |
1563 | * types other than dead_type. Given this, it's ok to check | |
1564 | * the key type before acquiring keyring->sem. | |
1565 | */ | |
1566 | if (!dead_type || !keyring->restrict_link || | |
1567 | keyring->restrict_link->keytype != dead_type) { | |
1568 | kleave(" [no restriction gc]"); | |
1569 | return; | |
1570 | } | |
1571 | ||
1572 | /* Lock the keyring to ensure that a link is not in progress */ | |
1573 | down_write(&keyring->sem); | |
1574 | ||
1575 | keyres = keyring->restrict_link; | |
1576 | ||
1577 | keyres->check = restrict_link_reject; | |
1578 | ||
1579 | key_put(keyres->key); | |
1580 | keyres->key = NULL; | |
1581 | keyres->keytype = NULL; | |
1582 | ||
1583 | up_write(&keyring->sem); | |
1584 | ||
1585 | kleave(" [restriction gc]"); | |
1586 | } |