Commit | Line | Data |
---|---|---|
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 DH |
715 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
716 | smp_read_barrier_depends(); | |
717 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) | |
718 | goto not_this_keyring; | |
719 | ||
381f20fc | 720 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 DH |
721 | node = assoc_array_ptr_to_node(ptr); |
722 | goto begin_node; | |
723 | } | |
724 | ||
725 | node = assoc_array_ptr_to_node(ptr); | |
726 | smp_read_barrier_depends(); | |
727 | ||
728 | ptr = node->slots[0]; | |
729 | if (!assoc_array_ptr_is_meta(ptr)) | |
730 | goto begin_node; | |
731 | ||
732 | descend_to_node: | |
733 | /* Descend to a more distal node in this keyring's content tree and go | |
734 | * through that. | |
735 | */ | |
736 | kdebug("descend"); | |
737 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
738 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
739 | smp_read_barrier_depends(); | |
381f20fc | 740 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 | 741 | BUG_ON(!assoc_array_ptr_is_node(ptr)); |
b2a4df20 | 742 | } |
9c5e45df | 743 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
744 | |
745 | begin_node: | |
746 | kdebug("begin_node"); | |
747 | smp_read_barrier_depends(); | |
748 | slot = 0; | |
749 | ascend_to_node: | |
750 | /* Go through the slots in a node */ | |
751 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
381f20fc | 752 | ptr = READ_ONCE(node->slots[slot]); |
b2a4df20 DH |
753 | |
754 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
755 | goto descend_to_node; | |
756 | ||
757 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 758 | continue; |
1da177e4 | 759 | |
b2a4df20 DH |
760 | key = keyring_ptr_to_key(ptr); |
761 | ||
762 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
763 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
764 | ctx->result = ERR_PTR(-ELOOP); | |
765 | return false; | |
766 | } | |
767 | goto not_this_keyring; | |
768 | } | |
769 | ||
770 | /* Search a nested keyring */ | |
771 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
772 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 773 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 774 | continue; |
1da177e4 LT |
775 | |
776 | /* stack the current position */ | |
31d5a79d | 777 | stack[sp].keyring = keyring; |
b2a4df20 DH |
778 | stack[sp].node = node; |
779 | stack[sp].slot = slot; | |
1da177e4 LT |
780 | sp++; |
781 | ||
782 | /* begin again with the new keyring */ | |
783 | keyring = key; | |
b2a4df20 DH |
784 | goto descend_to_keyring; |
785 | } | |
786 | ||
787 | /* We've dealt with all the slots in the current node, so now we need | |
788 | * to ascend to the parent and continue processing there. | |
789 | */ | |
381f20fc | 790 | ptr = READ_ONCE(node->back_pointer); |
b2a4df20 DH |
791 | slot = node->parent_slot; |
792 | ||
793 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
794 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
795 | smp_read_barrier_depends(); | |
381f20fc | 796 | ptr = READ_ONCE(shortcut->back_pointer); |
b2a4df20 DH |
797 | slot = shortcut->parent_slot; |
798 | } | |
799 | if (!ptr) | |
800 | goto not_this_keyring; | |
801 | node = assoc_array_ptr_to_node(ptr); | |
802 | smp_read_barrier_depends(); | |
803 | slot++; | |
804 | ||
805 | /* If we've ascended to the root (zero backpointer), we must have just | |
806 | * finished processing the leftmost branch rather than the root slots - | |
807 | * so there can't be any more keyrings for us to find. | |
808 | */ | |
809 | if (node->back_pointer) { | |
810 | kdebug("ascend %d", slot); | |
811 | goto ascend_to_node; | |
1da177e4 LT |
812 | } |
813 | ||
b2a4df20 DH |
814 | /* The keyring we're looking at was disqualified or didn't contain a |
815 | * matching key. | |
816 | */ | |
664cceb0 | 817 | not_this_keyring: |
b2a4df20 DH |
818 | kdebug("not_this_keyring %d", sp); |
819 | if (sp <= 0) { | |
820 | kleave(" = false"); | |
821 | return false; | |
1da177e4 LT |
822 | } |
823 | ||
b2a4df20 DH |
824 | /* Resume the processing of a keyring higher up in the tree */ |
825 | sp--; | |
826 | keyring = stack[sp].keyring; | |
827 | node = stack[sp].node; | |
828 | slot = stack[sp].slot + 1; | |
829 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
830 | goto ascend_to_node; | |
1da177e4 | 831 | |
b2a4df20 | 832 | /* We found a viable match */ |
664cceb0 | 833 | found: |
b2a4df20 | 834 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 835 | key_check(key); |
b2a4df20 | 836 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
074d5898 BW |
837 | key->last_used_at = ctx->now; |
838 | keyring->last_used_at = ctx->now; | |
b2a4df20 | 839 | while (sp > 0) |
074d5898 | 840 | stack[--sp].keyring->last_used_at = ctx->now; |
b2a4df20 DH |
841 | } |
842 | kleave(" = true"); | |
843 | return true; | |
844 | } | |
845 | ||
846 | /** | |
847 | * keyring_search_aux - Search a keyring tree for a key matching some criteria | |
848 | * @keyring_ref: A pointer to the keyring with possession indicator. | |
849 | * @ctx: The keyring search context. | |
850 | * | |
851 | * Search the supplied keyring tree for a key that matches the criteria given. | |
852 | * The root keyring and any linked keyrings must grant Search permission to the | |
853 | * caller to be searchable and keys can only be found if they too grant Search | |
854 | * to the caller. The possession flag on the root keyring pointer controls use | |
855 | * of the possessor bits in permissions checking of the entire tree. In | |
856 | * addition, the LSM gets to forbid keyring searches and key matches. | |
857 | * | |
858 | * The search is performed as a breadth-then-depth search up to the prescribed | |
859 | * limit (KEYRING_SEARCH_MAX_DEPTH). | |
860 | * | |
861 | * Keys are matched to the type provided and are then filtered by the match | |
862 | * function, which is given the description to use in any way it sees fit. The | |
863 | * match function may use any attributes of a key that it wishes to to | |
864 | * determine the match. Normally the match function from the key type would be | |
865 | * used. | |
866 | * | |
867 | * RCU can be used to prevent the keyring key lists from disappearing without | |
868 | * the need to take lots of locks. | |
869 | * | |
870 | * Returns a pointer to the found key and increments the key usage count if | |
871 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
872 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
873 | * specified keyring wasn't a keyring. | |
874 | * | |
875 | * In the case of a successful return, the possession attribute from | |
876 | * @keyring_ref is propagated to the returned key reference. | |
877 | */ | |
878 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, | |
879 | struct keyring_search_context *ctx) | |
880 | { | |
881 | struct key *keyring; | |
882 | long err; | |
883 | ||
884 | ctx->iterator = keyring_search_iterator; | |
885 | ctx->possessed = is_key_possessed(keyring_ref); | |
886 | ctx->result = ERR_PTR(-EAGAIN); | |
887 | ||
888 | keyring = key_ref_to_ptr(keyring_ref); | |
889 | key_check(keyring); | |
890 | ||
891 | if (keyring->type != &key_type_keyring) | |
892 | return ERR_PTR(-ENOTDIR); | |
893 | ||
894 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 895 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
896 | if (err < 0) |
897 | return ERR_PTR(err); | |
898 | } | |
899 | ||
900 | rcu_read_lock(); | |
074d5898 | 901 | ctx->now = ktime_get_real_seconds(); |
b2a4df20 DH |
902 | if (search_nested_keyrings(keyring, ctx)) |
903 | __key_get(key_ref_to_ptr(ctx->result)); | |
76d8aeab | 904 | rcu_read_unlock(); |
b2a4df20 | 905 | return ctx->result; |
a8b17ed0 | 906 | } |
1da177e4 | 907 | |
973c9f4f DH |
908 | /** |
909 | * keyring_search - Search the supplied keyring tree for a matching key | |
910 | * @keyring: The root of the keyring tree to be searched. | |
911 | * @type: The type of keyring we want to find. | |
912 | * @description: The name of the keyring we want to find. | |
913 | * | |
914 | * As keyring_search_aux() above, but using the current task's credentials and | |
b2a4df20 | 915 | * type's default matching function and preferred search method. |
1da177e4 | 916 | */ |
664cceb0 DH |
917 | key_ref_t keyring_search(key_ref_t keyring, |
918 | struct key_type *type, | |
919 | const char *description) | |
1da177e4 | 920 | { |
4bdf0bc3 DH |
921 | struct keyring_search_context ctx = { |
922 | .index_key.type = type, | |
923 | .index_key.description = description, | |
924 | .cred = current_cred(), | |
c06cfb08 | 925 | .match_data.cmp = key_default_cmp, |
46291959 DH |
926 | .match_data.raw_data = description, |
927 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
928 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 929 | }; |
46291959 DH |
930 | key_ref_t key; |
931 | int ret; | |
4bdf0bc3 | 932 | |
46291959 DH |
933 | if (type->match_preparse) { |
934 | ret = type->match_preparse(&ctx.match_data); | |
935 | if (ret < 0) | |
936 | return ERR_PTR(ret); | |
937 | } | |
938 | ||
939 | key = keyring_search_aux(keyring, &ctx); | |
940 | ||
941 | if (type->match_free) | |
942 | type->match_free(&ctx.match_data); | |
943 | return key; | |
a8b17ed0 | 944 | } |
1da177e4 LT |
945 | EXPORT_SYMBOL(keyring_search); |
946 | ||
6563c91f MM |
947 | static struct key_restriction *keyring_restriction_alloc( |
948 | key_restrict_link_func_t check) | |
949 | { | |
950 | struct key_restriction *keyres = | |
951 | kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
952 | ||
953 | if (!keyres) | |
954 | return ERR_PTR(-ENOMEM); | |
955 | ||
956 | keyres->check = check; | |
957 | ||
958 | return keyres; | |
959 | } | |
960 | ||
961 | /* | |
962 | * Semaphore to serialise restriction setup to prevent reference count | |
963 | * cycles through restriction key pointers. | |
964 | */ | |
965 | static DECLARE_RWSEM(keyring_serialise_restrict_sem); | |
966 | ||
967 | /* | |
968 | * Check for restriction cycles that would prevent keyring garbage collection. | |
969 | * keyring_serialise_restrict_sem must be held. | |
970 | */ | |
971 | static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, | |
972 | struct key_restriction *keyres) | |
973 | { | |
974 | while (keyres && keyres->key && | |
975 | keyres->key->type == &key_type_keyring) { | |
976 | if (keyres->key == dest_keyring) | |
977 | return true; | |
978 | ||
979 | keyres = keyres->key->restrict_link; | |
980 | } | |
981 | ||
982 | return false; | |
983 | } | |
984 | ||
985 | /** | |
986 | * keyring_restrict - Look up and apply a restriction to a keyring | |
987 | * | |
988 | * @keyring: The keyring to be restricted | |
989 | * @restriction: The restriction options to apply to the keyring | |
990 | */ | |
991 | int keyring_restrict(key_ref_t keyring_ref, const char *type, | |
992 | const char *restriction) | |
993 | { | |
994 | struct key *keyring; | |
995 | struct key_type *restrict_type = NULL; | |
996 | struct key_restriction *restrict_link; | |
997 | int ret = 0; | |
998 | ||
999 | keyring = key_ref_to_ptr(keyring_ref); | |
1000 | key_check(keyring); | |
1001 | ||
1002 | if (keyring->type != &key_type_keyring) | |
1003 | return -ENOTDIR; | |
1004 | ||
1005 | if (!type) { | |
1006 | restrict_link = keyring_restriction_alloc(restrict_link_reject); | |
1007 | } else { | |
1008 | restrict_type = key_type_lookup(type); | |
1009 | ||
1010 | if (IS_ERR(restrict_type)) | |
1011 | return PTR_ERR(restrict_type); | |
1012 | ||
1013 | if (!restrict_type->lookup_restriction) { | |
1014 | ret = -ENOENT; | |
1015 | goto error; | |
1016 | } | |
1017 | ||
1018 | restrict_link = restrict_type->lookup_restriction(restriction); | |
1019 | } | |
1020 | ||
1021 | if (IS_ERR(restrict_link)) { | |
1022 | ret = PTR_ERR(restrict_link); | |
1023 | goto error; | |
1024 | } | |
1025 | ||
1026 | down_write(&keyring->sem); | |
1027 | down_write(&keyring_serialise_restrict_sem); | |
1028 | ||
1029 | if (keyring->restrict_link) | |
1030 | ret = -EEXIST; | |
1031 | else if (keyring_detect_restriction_cycle(keyring, restrict_link)) | |
1032 | ret = -EDEADLK; | |
1033 | else | |
1034 | keyring->restrict_link = restrict_link; | |
1035 | ||
1036 | up_write(&keyring_serialise_restrict_sem); | |
1037 | up_write(&keyring->sem); | |
1038 | ||
1039 | if (ret < 0) { | |
1040 | key_put(restrict_link->key); | |
1041 | kfree(restrict_link); | |
1042 | } | |
1043 | ||
1044 | error: | |
1045 | if (restrict_type) | |
1046 | key_type_put(restrict_type); | |
1047 | ||
1048 | return ret; | |
1049 | } | |
1050 | EXPORT_SYMBOL(keyring_restrict); | |
1051 | ||
1da177e4 | 1052 | /* |
b2a4df20 | 1053 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
1054 | * |
1055 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
1056 | * permission is granted to modify the keyring as no check is made here. The |
1057 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
1058 | * |
1059 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
1060 | * successful and returns NULL if not found. Revoked and invalidated keys are |
1061 | * skipped over. | |
973c9f4f DH |
1062 | * |
1063 | * If successful, the possession indicator is propagated from the keyring ref | |
1064 | * to the returned key reference. | |
1da177e4 | 1065 | */ |
b2a4df20 DH |
1066 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
1067 | const struct keyring_index_key *index_key) | |
1da177e4 | 1068 | { |
664cceb0 | 1069 | struct key *keyring, *key; |
b2a4df20 | 1070 | const void *object; |
1da177e4 | 1071 | |
664cceb0 | 1072 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 1073 | |
b2a4df20 DH |
1074 | kenter("{%d},{%s,%s}", |
1075 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 1076 | |
b2a4df20 DH |
1077 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
1078 | index_key); | |
1da177e4 | 1079 | |
b2a4df20 DH |
1080 | if (object) |
1081 | goto found; | |
1082 | ||
1083 | kleave(" = NULL"); | |
1084 | return NULL; | |
1da177e4 | 1085 | |
c5b60b5e | 1086 | found: |
b2a4df20 DH |
1087 | key = keyring_ptr_to_key(object); |
1088 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
1089 | (1 << KEY_FLAG_REVOKED))) { | |
1090 | kleave(" = NULL [x]"); | |
1091 | return NULL; | |
1092 | } | |
ccc3e6d9 | 1093 | __key_get(key); |
b2a4df20 DH |
1094 | kleave(" = {%d}", key->serial); |
1095 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 1096 | } |
1da177e4 | 1097 | |
1da177e4 | 1098 | /* |
973c9f4f DH |
1099 | * Find a keyring with the specified name. |
1100 | * | |
237bbd29 EB |
1101 | * Only keyrings that have nonzero refcount, are not revoked, and are owned by a |
1102 | * user in the current user namespace are considered. If @uid_keyring is %true, | |
1103 | * the keyring additionally must have been allocated as a user or user session | |
1104 | * keyring; otherwise, it must grant Search permission directly to the caller. | |
973c9f4f DH |
1105 | * |
1106 | * Returns a pointer to the keyring with the keyring's refcount having being | |
1107 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 1108 | */ |
237bbd29 | 1109 | struct key *find_keyring_by_name(const char *name, bool uid_keyring) |
1da177e4 LT |
1110 | { |
1111 | struct key *keyring; | |
1112 | int bucket; | |
1113 | ||
1da177e4 | 1114 | if (!name) |
cea7daa3 | 1115 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
1116 | |
1117 | bucket = keyring_hash(name); | |
1118 | ||
1119 | read_lock(&keyring_name_lock); | |
1120 | ||
1121 | if (keyring_name_hash[bucket].next) { | |
1122 | /* search this hash bucket for a keyring with a matching name | |
1123 | * that's readable and that hasn't been revoked */ | |
1124 | list_for_each_entry(keyring, | |
1125 | &keyring_name_hash[bucket], | |
146aa8b1 | 1126 | name_link |
1da177e4 | 1127 | ) { |
9a56c2db | 1128 | if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) |
2ea190d0 SH |
1129 | continue; |
1130 | ||
76d8aeab | 1131 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1da177e4 LT |
1132 | continue; |
1133 | ||
1134 | if (strcmp(keyring->description, name) != 0) | |
1135 | continue; | |
1136 | ||
237bbd29 EB |
1137 | if (uid_keyring) { |
1138 | if (!test_bit(KEY_FLAG_UID_KEYRING, | |
1139 | &keyring->flags)) | |
1140 | continue; | |
1141 | } else { | |
1142 | if (key_permission(make_key_ref(keyring, 0), | |
1143 | KEY_NEED_SEARCH) < 0) | |
1144 | continue; | |
1145 | } | |
1da177e4 | 1146 | |
cea7daa3 TO |
1147 | /* we've got a match but we might end up racing with |
1148 | * key_cleanup() if the keyring is currently 'dead' | |
1149 | * (ie. it has a zero usage count) */ | |
fff29291 | 1150 | if (!refcount_inc_not_zero(&keyring->usage)) |
cea7daa3 | 1151 | continue; |
074d5898 | 1152 | keyring->last_used_at = ktime_get_real_seconds(); |
cea7daa3 | 1153 | goto out; |
1da177e4 LT |
1154 | } |
1155 | } | |
1156 | ||
1da177e4 | 1157 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1158 | out: |
1159 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1160 | return keyring; |
a8b17ed0 | 1161 | } |
1da177e4 | 1162 | |
b2a4df20 DH |
1163 | static int keyring_detect_cycle_iterator(const void *object, |
1164 | void *iterator_data) | |
1165 | { | |
1166 | struct keyring_search_context *ctx = iterator_data; | |
1167 | const struct key *key = keyring_ptr_to_key(object); | |
1168 | ||
1169 | kenter("{%d}", key->serial); | |
1170 | ||
979e0d74 DH |
1171 | /* We might get a keyring with matching index-key that is nonetheless a |
1172 | * different keyring. */ | |
46291959 | 1173 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1174 | return 0; |
1175 | ||
b2a4df20 DH |
1176 | ctx->result = ERR_PTR(-EDEADLK); |
1177 | return 1; | |
1178 | } | |
1179 | ||
1da177e4 | 1180 | /* |
973c9f4f DH |
1181 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1182 | * tree A at the topmost level (ie: as a direct child of A). | |
1183 | * | |
1184 | * Since we are adding B to A at the top level, checking for cycles should just | |
1185 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1186 | */ |
1187 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1188 | { | |
b2a4df20 | 1189 | struct keyring_search_context ctx = { |
46291959 DH |
1190 | .index_key = A->index_key, |
1191 | .match_data.raw_data = A, | |
1192 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1193 | .iterator = keyring_detect_cycle_iterator, | |
1194 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1195 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1196 | KEYRING_SEARCH_NO_CHECK_PERM | | |
1197 | KEYRING_SEARCH_DETECT_TOO_DEEP), | |
b2a4df20 | 1198 | }; |
1da177e4 | 1199 | |
76d8aeab | 1200 | rcu_read_lock(); |
b2a4df20 | 1201 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1202 | rcu_read_unlock(); |
b2a4df20 | 1203 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1204 | } |
cab8eb59 | 1205 | |
1da177e4 | 1206 | /* |
973c9f4f | 1207 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1208 | */ |
b2a4df20 DH |
1209 | int __key_link_begin(struct key *keyring, |
1210 | const struct keyring_index_key *index_key, | |
1211 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1212 | __acquires(&keyring->sem) |
423b9788 | 1213 | __acquires(&keyring_serialise_link_sem) |
1da177e4 | 1214 | { |
b2a4df20 DH |
1215 | struct assoc_array_edit *edit; |
1216 | int ret; | |
1da177e4 | 1217 | |
16feef43 | 1218 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1219 | keyring->serial, index_key->type->name, index_key->description); |
1220 | ||
1221 | BUG_ON(index_key->desc_len == 0); | |
1da177e4 | 1222 | |
1da177e4 | 1223 | if (keyring->type != &key_type_keyring) |
f70e2e06 DH |
1224 | return -ENOTDIR; |
1225 | ||
1226 | down_write(&keyring->sem); | |
1227 | ||
1228 | ret = -EKEYREVOKED; | |
1229 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
1230 | goto error_krsem; | |
1da177e4 | 1231 | |
f70e2e06 DH |
1232 | /* serialise link/link calls to prevent parallel calls causing a cycle |
1233 | * when linking two keyring in opposite orders */ | |
16feef43 | 1234 | if (index_key->type == &key_type_keyring) |
553d603c DH |
1235 | down_write(&keyring_serialise_link_sem); |
1236 | ||
b2a4df20 DH |
1237 | /* Create an edit script that will insert/replace the key in the |
1238 | * keyring tree. | |
1239 | */ | |
1240 | edit = assoc_array_insert(&keyring->keys, | |
1241 | &keyring_assoc_array_ops, | |
1242 | index_key, | |
1243 | NULL); | |
1244 | if (IS_ERR(edit)) { | |
1245 | ret = PTR_ERR(edit); | |
034faeb9 DH |
1246 | goto error_sem; |
1247 | } | |
1248 | ||
1249 | /* If we're not replacing a link in-place then we're going to need some | |
1250 | * extra quota. | |
1251 | */ | |
1252 | if (!edit->dead_leaf) { | |
1253 | ret = key_payload_reserve(keyring, | |
1254 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1255 | if (ret < 0) | |
1256 | goto error_cancel; | |
1da177e4 LT |
1257 | } |
1258 | ||
b2a4df20 | 1259 | *_edit = edit; |
f70e2e06 DH |
1260 | kleave(" = 0"); |
1261 | return 0; | |
1da177e4 | 1262 | |
034faeb9 DH |
1263 | error_cancel: |
1264 | assoc_array_cancel_edit(edit); | |
f70e2e06 | 1265 | error_sem: |
16feef43 | 1266 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1267 | up_write(&keyring_serialise_link_sem); |
1268 | error_krsem: | |
1269 | up_write(&keyring->sem); | |
1270 | kleave(" = %d", ret); | |
1271 | return ret; | |
1272 | } | |
1da177e4 | 1273 | |
f70e2e06 | 1274 | /* |
973c9f4f DH |
1275 | * Check already instantiated keys aren't going to be a problem. |
1276 | * | |
1277 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1278 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1279 | */ |
1280 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1281 | { | |
1282 | if (key->type == &key_type_keyring) | |
1283 | /* check that we aren't going to create a cycle by linking one | |
1284 | * keyring to another */ | |
1285 | return keyring_detect_cycle(keyring, key); | |
1286 | return 0; | |
1287 | } | |
1288 | ||
1289 | /* | |
973c9f4f DH |
1290 | * Link a key into to a keyring. |
1291 | * | |
1292 | * Must be called with __key_link_begin() having being called. Discards any | |
1293 | * already extant link to matching key if there is one, so that each keyring | |
1294 | * holds at most one link to any given key of a particular type+description | |
1295 | * combination. | |
f70e2e06 | 1296 | */ |
b2a4df20 | 1297 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1298 | { |
ccc3e6d9 | 1299 | __key_get(key); |
b2a4df20 DH |
1300 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1301 | assoc_array_apply_edit(*_edit); | |
1302 | *_edit = NULL; | |
f70e2e06 DH |
1303 | } |
1304 | ||
1305 | /* | |
973c9f4f DH |
1306 | * Finish linking a key into to a keyring. |
1307 | * | |
1308 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1309 | */ |
16feef43 DH |
1310 | void __key_link_end(struct key *keyring, |
1311 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1312 | struct assoc_array_edit *edit) |
f70e2e06 | 1313 | __releases(&keyring->sem) |
423b9788 | 1314 | __releases(&keyring_serialise_link_sem) |
f70e2e06 | 1315 | { |
16feef43 | 1316 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1317 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1318 | |
16feef43 | 1319 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1320 | up_write(&keyring_serialise_link_sem); |
1321 | ||
ca4da5dd CIK |
1322 | if (edit) { |
1323 | if (!edit->dead_leaf) { | |
1324 | key_payload_reserve(keyring, | |
1325 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1326 | } | |
b2a4df20 | 1327 | assoc_array_cancel_edit(edit); |
f70e2e06 DH |
1328 | } |
1329 | up_write(&keyring->sem); | |
1330 | } | |
1da177e4 | 1331 | |
5ac7eace DH |
1332 | /* |
1333 | * Check addition of keys to restricted keyrings. | |
1334 | */ | |
1335 | static int __key_link_check_restriction(struct key *keyring, struct key *key) | |
1336 | { | |
2b6aa412 | 1337 | if (!keyring->restrict_link || !keyring->restrict_link->check) |
5ac7eace | 1338 | return 0; |
2b6aa412 MM |
1339 | return keyring->restrict_link->check(keyring, key->type, &key->payload, |
1340 | keyring->restrict_link->key); | |
5ac7eace DH |
1341 | } |
1342 | ||
973c9f4f DH |
1343 | /** |
1344 | * key_link - Link a key to a keyring | |
1345 | * @keyring: The keyring to make the link in. | |
1346 | * @key: The key to link to. | |
1347 | * | |
1348 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1349 | * on that key and the key can potentially be found by searching that keyring. | |
1350 | * | |
1351 | * This function will write-lock the keyring's semaphore and will consume some | |
1352 | * of the user's key data quota to hold the link. | |
1353 | * | |
1354 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1355 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1356 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1357 | * another link or -ENOMEM if there's insufficient memory. | |
1358 | * | |
1359 | * It is assumed that the caller has checked that it is permitted for a link to | |
1360 | * be made (the keyring should have Write permission and the key Link | |
1361 | * permission). | |
1da177e4 LT |
1362 | */ |
1363 | int key_link(struct key *keyring, struct key *key) | |
1364 | { | |
b2a4df20 | 1365 | struct assoc_array_edit *edit; |
1da177e4 LT |
1366 | int ret; |
1367 | ||
fff29291 | 1368 | kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
b2a4df20 | 1369 | |
1da177e4 LT |
1370 | key_check(keyring); |
1371 | key_check(key); | |
1372 | ||
b2a4df20 | 1373 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
f70e2e06 | 1374 | if (ret == 0) { |
fff29291 | 1375 | kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
5ac7eace DH |
1376 | ret = __key_link_check_restriction(keyring, key); |
1377 | if (ret == 0) | |
1378 | ret = __key_link_check_live_key(keyring, key); | |
f70e2e06 | 1379 | if (ret == 0) |
b2a4df20 DH |
1380 | __key_link(key, &edit); |
1381 | __key_link_end(keyring, &key->index_key, edit); | |
f70e2e06 | 1382 | } |
1da177e4 | 1383 | |
fff29291 | 1384 | kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage)); |
1da177e4 | 1385 | return ret; |
f70e2e06 | 1386 | } |
1da177e4 LT |
1387 | EXPORT_SYMBOL(key_link); |
1388 | ||
973c9f4f DH |
1389 | /** |
1390 | * key_unlink - Unlink the first link to a key from a keyring. | |
1391 | * @keyring: The keyring to remove the link from. | |
1392 | * @key: The key the link is to. | |
1393 | * | |
1394 | * Remove a link from a keyring to a key. | |
1395 | * | |
1396 | * This function will write-lock the keyring's semaphore. | |
1397 | * | |
1398 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1399 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1400 | * memory. | |
1401 | * | |
1402 | * It is assumed that the caller has checked that it is permitted for a link to | |
1403 | * be removed (the keyring should have Write permission; no permissions are | |
1404 | * required on the key). | |
1da177e4 LT |
1405 | */ |
1406 | int key_unlink(struct key *keyring, struct key *key) | |
1407 | { | |
b2a4df20 DH |
1408 | struct assoc_array_edit *edit; |
1409 | int ret; | |
1da177e4 LT |
1410 | |
1411 | key_check(keyring); | |
1412 | key_check(key); | |
1413 | ||
1da177e4 | 1414 | if (keyring->type != &key_type_keyring) |
b2a4df20 | 1415 | return -ENOTDIR; |
1da177e4 LT |
1416 | |
1417 | down_write(&keyring->sem); | |
1418 | ||
b2a4df20 DH |
1419 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, |
1420 | &key->index_key); | |
1421 | if (IS_ERR(edit)) { | |
1422 | ret = PTR_ERR(edit); | |
1423 | goto error; | |
1da177e4 | 1424 | } |
1da177e4 | 1425 | ret = -ENOENT; |
b2a4df20 DH |
1426 | if (edit == NULL) |
1427 | goto error; | |
1da177e4 | 1428 | |
b2a4df20 | 1429 | assoc_array_apply_edit(edit); |
034faeb9 | 1430 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); |
1da177e4 LT |
1431 | ret = 0; |
1432 | ||
76d8aeab | 1433 | error: |
76d8aeab | 1434 | up_write(&keyring->sem); |
b2a4df20 | 1435 | return ret; |
a8b17ed0 | 1436 | } |
1da177e4 LT |
1437 | EXPORT_SYMBOL(key_unlink); |
1438 | ||
973c9f4f DH |
1439 | /** |
1440 | * keyring_clear - Clear a keyring | |
1441 | * @keyring: The keyring to clear. | |
1442 | * | |
1443 | * Clear the contents of the specified keyring. | |
1444 | * | |
1445 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1446 | */ |
1447 | int keyring_clear(struct key *keyring) | |
1448 | { | |
b2a4df20 | 1449 | struct assoc_array_edit *edit; |
76d8aeab | 1450 | int ret; |
1da177e4 | 1451 | |
b2a4df20 DH |
1452 | if (keyring->type != &key_type_keyring) |
1453 | return -ENOTDIR; | |
1da177e4 | 1454 | |
b2a4df20 | 1455 | down_write(&keyring->sem); |
1da177e4 | 1456 | |
b2a4df20 DH |
1457 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1458 | if (IS_ERR(edit)) { | |
1459 | ret = PTR_ERR(edit); | |
1460 | } else { | |
1461 | if (edit) | |
1462 | assoc_array_apply_edit(edit); | |
1463 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1464 | ret = 0; |
1465 | } | |
1466 | ||
b2a4df20 | 1467 | up_write(&keyring->sem); |
1da177e4 | 1468 | return ret; |
a8b17ed0 | 1469 | } |
1da177e4 | 1470 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1471 | |
31204ed9 | 1472 | /* |
973c9f4f DH |
1473 | * Dispose of the links from a revoked keyring. |
1474 | * | |
1475 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1476 | */ |
1477 | static void keyring_revoke(struct key *keyring) | |
1478 | { | |
b2a4df20 | 1479 | struct assoc_array_edit *edit; |
f0641cba | 1480 | |
b2a4df20 DH |
1481 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1482 | if (!IS_ERR(edit)) { | |
1483 | if (edit) | |
1484 | assoc_array_apply_edit(edit); | |
1485 | key_payload_reserve(keyring, 0); | |
1486 | } | |
1487 | } | |
31204ed9 | 1488 | |
62fe3182 | 1489 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1490 | { |
1491 | struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1492 | time64_t *limit = iterator_data; |
31204ed9 | 1493 | |
b2a4df20 DH |
1494 | if (key_is_dead(key, *limit)) |
1495 | return false; | |
1496 | key_get(key); | |
1497 | return true; | |
a8b17ed0 | 1498 | } |
5d135440 | 1499 | |
62fe3182 DH |
1500 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1501 | { | |
1502 | const struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1503 | time64_t *limit = iterator_data; |
62fe3182 DH |
1504 | |
1505 | key_check(key); | |
1506 | return key_is_dead(key, *limit); | |
1507 | } | |
1508 | ||
5d135440 | 1509 | /* |
62fe3182 | 1510 | * Garbage collect pointers from a keyring. |
973c9f4f | 1511 | * |
62fe3182 DH |
1512 | * Not called with any locks held. The keyring's key struct will not be |
1513 | * deallocated under us as only our caller may deallocate it. | |
5d135440 | 1514 | */ |
074d5898 | 1515 | void keyring_gc(struct key *keyring, time64_t limit) |
5d135440 | 1516 | { |
62fe3182 DH |
1517 | int result; |
1518 | ||
1519 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1520 | |
62fe3182 DH |
1521 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1522 | (1 << KEY_FLAG_REVOKED))) | |
1523 | goto dont_gc; | |
1524 | ||
1525 | /* scan the keyring looking for dead keys */ | |
1526 | rcu_read_lock(); | |
1527 | result = assoc_array_iterate(&keyring->keys, | |
1528 | keyring_gc_check_iterator, &limit); | |
1529 | rcu_read_unlock(); | |
1530 | if (result == true) | |
1531 | goto do_gc; | |
1532 | ||
1533 | dont_gc: | |
1534 | kleave(" [no gc]"); | |
1535 | return; | |
1536 | ||
1537 | do_gc: | |
5d135440 | 1538 | down_write(&keyring->sem); |
b2a4df20 | 1539 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1540 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1541 | up_write(&keyring->sem); |
62fe3182 | 1542 | kleave(" [gc]"); |
5d135440 | 1543 | } |
2b6aa412 MM |
1544 | |
1545 | /* | |
1546 | * Garbage collect restriction pointers from a keyring. | |
1547 | * | |
1548 | * Keyring restrictions are associated with a key type, and must be cleaned | |
1549 | * up if the key type is unregistered. The restriction is altered to always | |
1550 | * reject additional keys so a keyring cannot be opened up by unregistering | |
1551 | * a key type. | |
1552 | * | |
1553 | * Not called with any keyring locks held. The keyring's key struct will not | |
1554 | * be deallocated under us as only our caller may deallocate it. | |
1555 | * | |
1556 | * The caller is required to hold key_types_sem and dead_type->sem. This is | |
1557 | * fulfilled by key_gc_keytype() holding the locks on behalf of | |
1558 | * key_garbage_collector(), which it invokes on a workqueue. | |
1559 | */ | |
1560 | void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) | |
1561 | { | |
1562 | struct key_restriction *keyres; | |
1563 | ||
1564 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
1565 | ||
1566 | /* | |
1567 | * keyring->restrict_link is only assigned at key allocation time | |
1568 | * or with the key type locked, so the only values that could be | |
1569 | * concurrently assigned to keyring->restrict_link are for key | |
1570 | * types other than dead_type. Given this, it's ok to check | |
1571 | * the key type before acquiring keyring->sem. | |
1572 | */ | |
1573 | if (!dead_type || !keyring->restrict_link || | |
1574 | keyring->restrict_link->keytype != dead_type) { | |
1575 | kleave(" [no restriction gc]"); | |
1576 | return; | |
1577 | } | |
1578 | ||
1579 | /* Lock the keyring to ensure that a link is not in progress */ | |
1580 | down_write(&keyring->sem); | |
1581 | ||
1582 | keyres = keyring->restrict_link; | |
1583 | ||
1584 | keyres->check = restrict_link_reject; | |
1585 | ||
1586 | key_put(keyres->key); | |
1587 | keyres->key = NULL; | |
1588 | keyres->keytype = NULL; | |
1589 | ||
1590 | up_write(&keyring->sem); | |
1591 | ||
1592 | kleave(" [restriction gc]"); | |
1593 | } |