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, |
b2a4df20 | 92 | .match = user_match, |
31204ed9 | 93 | .revoke = keyring_revoke, |
1da177e4 LT |
94 | .destroy = keyring_destroy, |
95 | .describe = keyring_describe, | |
96 | .read = keyring_read, | |
97 | }; | |
7318226e DH |
98 | EXPORT_SYMBOL(key_type_keyring); |
99 | ||
1da177e4 | 100 | /* |
973c9f4f DH |
101 | * Semaphore to serialise link/link calls to prevent two link calls in parallel |
102 | * introducing a cycle. | |
1da177e4 | 103 | */ |
1ae8f407 | 104 | static DECLARE_RWSEM(keyring_serialise_link_sem); |
1da177e4 | 105 | |
1da177e4 | 106 | /* |
973c9f4f DH |
107 | * Publish the name of a keyring so that it can be found by name (if it has |
108 | * one). | |
1da177e4 | 109 | */ |
69664cf1 | 110 | static void keyring_publish_name(struct key *keyring) |
1da177e4 LT |
111 | { |
112 | int bucket; | |
113 | ||
114 | if (keyring->description) { | |
115 | bucket = keyring_hash(keyring->description); | |
116 | ||
117 | write_lock(&keyring_name_lock); | |
118 | ||
119 | if (!keyring_name_hash[bucket].next) | |
120 | INIT_LIST_HEAD(&keyring_name_hash[bucket]); | |
121 | ||
122 | list_add_tail(&keyring->type_data.link, | |
123 | &keyring_name_hash[bucket]); | |
124 | ||
125 | write_unlock(&keyring_name_lock); | |
126 | } | |
a8b17ed0 | 127 | } |
1da177e4 | 128 | |
5d19e20b DH |
129 | /* |
130 | * Preparse a keyring payload | |
131 | */ | |
132 | static int keyring_preparse(struct key_preparsed_payload *prep) | |
133 | { | |
134 | return prep->datalen != 0 ? -EINVAL : 0; | |
135 | } | |
136 | ||
137 | /* | |
138 | * Free a preparse of a user defined key payload | |
139 | */ | |
140 | static void keyring_free_preparse(struct key_preparsed_payload *prep) | |
141 | { | |
142 | } | |
143 | ||
1da177e4 | 144 | /* |
973c9f4f DH |
145 | * Initialise a keyring. |
146 | * | |
147 | * Returns 0 on success, -EINVAL if given any data. | |
1da177e4 LT |
148 | */ |
149 | static int keyring_instantiate(struct key *keyring, | |
cf7f601c | 150 | struct key_preparsed_payload *prep) |
1da177e4 | 151 | { |
5d19e20b DH |
152 | assoc_array_init(&keyring->keys); |
153 | /* make the keyring available by name if it has one */ | |
154 | keyring_publish_name(keyring); | |
155 | return 0; | |
a8b17ed0 | 156 | } |
1da177e4 | 157 | |
1da177e4 | 158 | /* |
b2a4df20 DH |
159 | * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd |
160 | * fold the carry back too, but that requires inline asm. | |
161 | */ | |
162 | static u64 mult_64x32_and_fold(u64 x, u32 y) | |
163 | { | |
164 | u64 hi = (u64)(u32)(x >> 32) * y; | |
165 | u64 lo = (u64)(u32)(x) * y; | |
166 | return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); | |
167 | } | |
168 | ||
169 | /* | |
170 | * Hash a key type and description. | |
171 | */ | |
172 | static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) | |
173 | { | |
174 | const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; | |
d54e58b7 | 175 | const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; |
b2a4df20 DH |
176 | const char *description = index_key->description; |
177 | unsigned long hash, type; | |
178 | u32 piece; | |
179 | u64 acc; | |
180 | int n, desc_len = index_key->desc_len; | |
181 | ||
182 | type = (unsigned long)index_key->type; | |
183 | ||
184 | acc = mult_64x32_and_fold(type, desc_len + 13); | |
185 | acc = mult_64x32_and_fold(acc, 9207); | |
186 | for (;;) { | |
187 | n = desc_len; | |
188 | if (n <= 0) | |
189 | break; | |
190 | if (n > 4) | |
191 | n = 4; | |
192 | piece = 0; | |
193 | memcpy(&piece, description, n); | |
194 | description += n; | |
195 | desc_len -= n; | |
196 | acc = mult_64x32_and_fold(acc, piece); | |
197 | acc = mult_64x32_and_fold(acc, 9207); | |
198 | } | |
199 | ||
200 | /* Fold the hash down to 32 bits if need be. */ | |
201 | hash = acc; | |
202 | if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) | |
203 | hash ^= acc >> 32; | |
204 | ||
205 | /* Squidge all the keyrings into a separate part of the tree to | |
206 | * ordinary keys by making sure the lowest level segment in the hash is | |
207 | * zero for keyrings and non-zero otherwise. | |
208 | */ | |
d54e58b7 | 209 | if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) |
b2a4df20 | 210 | return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; |
d54e58b7 DH |
211 | if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) |
212 | return (hash + (hash << level_shift)) & ~fan_mask; | |
b2a4df20 DH |
213 | return hash; |
214 | } | |
215 | ||
216 | /* | |
217 | * Build the next index key chunk. | |
218 | * | |
219 | * On 32-bit systems the index key is laid out as: | |
220 | * | |
221 | * 0 4 5 9... | |
222 | * hash desclen typeptr desc[] | |
223 | * | |
224 | * On 64-bit systems: | |
225 | * | |
226 | * 0 8 9 17... | |
227 | * hash desclen typeptr desc[] | |
228 | * | |
229 | * We return it one word-sized chunk at a time. | |
1da177e4 | 230 | */ |
b2a4df20 DH |
231 | static unsigned long keyring_get_key_chunk(const void *data, int level) |
232 | { | |
233 | const struct keyring_index_key *index_key = data; | |
234 | unsigned long chunk = 0; | |
235 | long offset = 0; | |
236 | int desc_len = index_key->desc_len, n = sizeof(chunk); | |
237 | ||
238 | level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; | |
239 | switch (level) { | |
240 | case 0: | |
241 | return hash_key_type_and_desc(index_key); | |
242 | case 1: | |
243 | return ((unsigned long)index_key->type << 8) | desc_len; | |
244 | case 2: | |
245 | if (desc_len == 0) | |
246 | return (u8)((unsigned long)index_key->type >> | |
247 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
248 | n--; | |
249 | offset = 1; | |
250 | default: | |
251 | offset += sizeof(chunk) - 1; | |
252 | offset += (level - 3) * sizeof(chunk); | |
253 | if (offset >= desc_len) | |
254 | return 0; | |
255 | desc_len -= offset; | |
256 | if (desc_len > n) | |
257 | desc_len = n; | |
258 | offset += desc_len; | |
259 | do { | |
260 | chunk <<= 8; | |
261 | chunk |= ((u8*)index_key->description)[--offset]; | |
262 | } while (--desc_len > 0); | |
263 | ||
264 | if (level == 2) { | |
265 | chunk <<= 8; | |
266 | chunk |= (u8)((unsigned long)index_key->type >> | |
267 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
268 | } | |
269 | return chunk; | |
270 | } | |
271 | } | |
272 | ||
273 | static unsigned long keyring_get_object_key_chunk(const void *object, int level) | |
274 | { | |
275 | const struct key *key = keyring_ptr_to_key(object); | |
276 | return keyring_get_key_chunk(&key->index_key, level); | |
277 | } | |
278 | ||
279 | static bool keyring_compare_object(const void *object, const void *data) | |
1da177e4 | 280 | { |
b2a4df20 DH |
281 | const struct keyring_index_key *index_key = data; |
282 | const struct key *key = keyring_ptr_to_key(object); | |
283 | ||
284 | return key->index_key.type == index_key->type && | |
285 | key->index_key.desc_len == index_key->desc_len && | |
286 | memcmp(key->index_key.description, index_key->description, | |
287 | index_key->desc_len) == 0; | |
a8b17ed0 | 288 | } |
1da177e4 | 289 | |
b2a4df20 DH |
290 | /* |
291 | * Compare the index keys of a pair of objects and determine the bit position | |
292 | * at which they differ - if they differ. | |
293 | */ | |
23fd78d7 | 294 | static int keyring_diff_objects(const void *object, const void *data) |
b2a4df20 | 295 | { |
23fd78d7 | 296 | const struct key *key_a = keyring_ptr_to_key(object); |
b2a4df20 | 297 | const struct keyring_index_key *a = &key_a->index_key; |
23fd78d7 | 298 | const struct keyring_index_key *b = data; |
b2a4df20 DH |
299 | unsigned long seg_a, seg_b; |
300 | int level, i; | |
301 | ||
302 | level = 0; | |
303 | seg_a = hash_key_type_and_desc(a); | |
304 | seg_b = hash_key_type_and_desc(b); | |
305 | if ((seg_a ^ seg_b) != 0) | |
306 | goto differ; | |
307 | ||
308 | /* The number of bits contributed by the hash is controlled by a | |
309 | * constant in the assoc_array headers. Everything else thereafter we | |
310 | * can deal with as being machine word-size dependent. | |
311 | */ | |
312 | level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; | |
313 | seg_a = a->desc_len; | |
314 | seg_b = b->desc_len; | |
315 | if ((seg_a ^ seg_b) != 0) | |
316 | goto differ; | |
317 | ||
318 | /* The next bit may not work on big endian */ | |
319 | level++; | |
320 | seg_a = (unsigned long)a->type; | |
321 | seg_b = (unsigned long)b->type; | |
322 | if ((seg_a ^ seg_b) != 0) | |
323 | goto differ; | |
324 | ||
325 | level += sizeof(unsigned long); | |
326 | if (a->desc_len == 0) | |
327 | goto same; | |
328 | ||
329 | i = 0; | |
330 | if (((unsigned long)a->description | (unsigned long)b->description) & | |
331 | (sizeof(unsigned long) - 1)) { | |
332 | do { | |
333 | seg_a = *(unsigned long *)(a->description + i); | |
334 | seg_b = *(unsigned long *)(b->description + i); | |
335 | if ((seg_a ^ seg_b) != 0) | |
336 | goto differ_plus_i; | |
337 | i += sizeof(unsigned long); | |
338 | } while (i < (a->desc_len & (sizeof(unsigned long) - 1))); | |
339 | } | |
340 | ||
341 | for (; i < a->desc_len; i++) { | |
342 | seg_a = *(unsigned char *)(a->description + i); | |
343 | seg_b = *(unsigned char *)(b->description + i); | |
344 | if ((seg_a ^ seg_b) != 0) | |
345 | goto differ_plus_i; | |
346 | } | |
347 | ||
348 | same: | |
349 | return -1; | |
350 | ||
351 | differ_plus_i: | |
352 | level += i; | |
353 | differ: | |
354 | i = level * 8 + __ffs(seg_a ^ seg_b); | |
355 | return i; | |
356 | } | |
357 | ||
358 | /* | |
359 | * Free an object after stripping the keyring flag off of the pointer. | |
360 | */ | |
361 | static void keyring_free_object(void *object) | |
362 | { | |
363 | key_put(keyring_ptr_to_key(object)); | |
364 | } | |
365 | ||
366 | /* | |
367 | * Operations for keyring management by the index-tree routines. | |
368 | */ | |
369 | static const struct assoc_array_ops keyring_assoc_array_ops = { | |
370 | .get_key_chunk = keyring_get_key_chunk, | |
371 | .get_object_key_chunk = keyring_get_object_key_chunk, | |
372 | .compare_object = keyring_compare_object, | |
373 | .diff_objects = keyring_diff_objects, | |
374 | .free_object = keyring_free_object, | |
375 | }; | |
376 | ||
1da177e4 | 377 | /* |
973c9f4f DH |
378 | * Clean up a keyring when it is destroyed. Unpublish its name if it had one |
379 | * and dispose of its data. | |
233e4735 DH |
380 | * |
381 | * The garbage collector detects the final key_put(), removes the keyring from | |
382 | * the serial number tree and then does RCU synchronisation before coming here, | |
383 | * so we shouldn't need to worry about code poking around here with the RCU | |
384 | * readlock held by this time. | |
1da177e4 LT |
385 | */ |
386 | static void keyring_destroy(struct key *keyring) | |
387 | { | |
1da177e4 LT |
388 | if (keyring->description) { |
389 | write_lock(&keyring_name_lock); | |
94efe72f DH |
390 | |
391 | if (keyring->type_data.link.next != NULL && | |
392 | !list_empty(&keyring->type_data.link)) | |
393 | list_del(&keyring->type_data.link); | |
394 | ||
1da177e4 LT |
395 | write_unlock(&keyring_name_lock); |
396 | } | |
397 | ||
b2a4df20 | 398 | assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); |
a8b17ed0 | 399 | } |
1da177e4 | 400 | |
1da177e4 | 401 | /* |
973c9f4f | 402 | * Describe a keyring for /proc. |
1da177e4 LT |
403 | */ |
404 | static void keyring_describe(const struct key *keyring, struct seq_file *m) | |
405 | { | |
c8563473 | 406 | if (keyring->description) |
1da177e4 | 407 | seq_puts(m, keyring->description); |
c8563473 | 408 | else |
1da177e4 | 409 | seq_puts(m, "[anon]"); |
1da177e4 | 410 | |
78b7280c | 411 | if (key_is_instantiated(keyring)) { |
b2a4df20 DH |
412 | if (keyring->keys.nr_leaves_on_tree != 0) |
413 | seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); | |
78b7280c DH |
414 | else |
415 | seq_puts(m, ": empty"); | |
78b7280c | 416 | } |
a8b17ed0 | 417 | } |
1da177e4 | 418 | |
b2a4df20 DH |
419 | struct keyring_read_iterator_context { |
420 | size_t qty; | |
421 | size_t count; | |
422 | key_serial_t __user *buffer; | |
423 | }; | |
424 | ||
425 | static int keyring_read_iterator(const void *object, void *data) | |
426 | { | |
427 | struct keyring_read_iterator_context *ctx = data; | |
428 | const struct key *key = keyring_ptr_to_key(object); | |
429 | int ret; | |
430 | ||
431 | kenter("{%s,%d},,{%zu/%zu}", | |
432 | key->type->name, key->serial, ctx->count, ctx->qty); | |
433 | ||
434 | if (ctx->count >= ctx->qty) | |
435 | return 1; | |
436 | ||
437 | ret = put_user(key->serial, ctx->buffer); | |
438 | if (ret < 0) | |
439 | return ret; | |
440 | ctx->buffer++; | |
441 | ctx->count += sizeof(key->serial); | |
442 | return 0; | |
443 | } | |
444 | ||
1da177e4 | 445 | /* |
973c9f4f DH |
446 | * Read a list of key IDs from the keyring's contents in binary form |
447 | * | |
b2a4df20 DH |
448 | * The keyring's semaphore is read-locked by the caller. This prevents someone |
449 | * from modifying it under us - which could cause us to read key IDs multiple | |
450 | * times. | |
1da177e4 LT |
451 | */ |
452 | static long keyring_read(const struct key *keyring, | |
453 | char __user *buffer, size_t buflen) | |
454 | { | |
b2a4df20 DH |
455 | struct keyring_read_iterator_context ctx; |
456 | unsigned long nr_keys; | |
457 | int ret; | |
1da177e4 | 458 | |
b2a4df20 DH |
459 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
460 | ||
461 | if (buflen & (sizeof(key_serial_t) - 1)) | |
462 | return -EINVAL; | |
463 | ||
464 | nr_keys = keyring->keys.nr_leaves_on_tree; | |
465 | if (nr_keys == 0) | |
466 | return 0; | |
1da177e4 | 467 | |
b2a4df20 DH |
468 | /* Calculate how much data we could return */ |
469 | ctx.qty = nr_keys * sizeof(key_serial_t); | |
470 | ||
471 | if (!buffer || !buflen) | |
472 | return ctx.qty; | |
473 | ||
474 | if (buflen > ctx.qty) | |
475 | ctx.qty = buflen; | |
476 | ||
477 | /* Copy the IDs of the subscribed keys into the buffer */ | |
478 | ctx.buffer = (key_serial_t __user *)buffer; | |
479 | ctx.count = 0; | |
480 | ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx); | |
481 | if (ret < 0) { | |
482 | kleave(" = %d [iterate]", ret); | |
483 | return ret; | |
1da177e4 LT |
484 | } |
485 | ||
b2a4df20 DH |
486 | kleave(" = %zu [ok]", ctx.count); |
487 | return ctx.count; | |
a8b17ed0 | 488 | } |
1da177e4 | 489 | |
1da177e4 | 490 | /* |
973c9f4f | 491 | * Allocate a keyring and link into the destination keyring. |
1da177e4 | 492 | */ |
9a56c2db | 493 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
96b5c8fe DH |
494 | const struct cred *cred, key_perm_t perm, |
495 | unsigned long flags, struct key *dest) | |
1da177e4 LT |
496 | { |
497 | struct key *keyring; | |
498 | int ret; | |
499 | ||
500 | keyring = key_alloc(&key_type_keyring, description, | |
96b5c8fe | 501 | uid, gid, cred, perm, flags); |
1da177e4 | 502 | if (!IS_ERR(keyring)) { |
3e30148c | 503 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
504 | if (ret < 0) { |
505 | key_put(keyring); | |
506 | keyring = ERR_PTR(ret); | |
507 | } | |
508 | } | |
509 | ||
510 | return keyring; | |
a8b17ed0 | 511 | } |
f8aa23a5 | 512 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 513 | |
b2a4df20 DH |
514 | /* |
515 | * Iteration function to consider each key found. | |
1da177e4 | 516 | */ |
b2a4df20 | 517 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 518 | { |
b2a4df20 DH |
519 | struct keyring_search_context *ctx = iterator_data; |
520 | const struct key *key = keyring_ptr_to_key(object); | |
521 | unsigned long kflags = key->flags; | |
1da177e4 | 522 | |
b2a4df20 | 523 | kenter("{%d}", key->serial); |
1da177e4 | 524 | |
b2a4df20 DH |
525 | /* ignore keys not of this type */ |
526 | if (key->type != ctx->index_key.type) { | |
527 | kleave(" = 0 [!type]"); | |
528 | return 0; | |
29db9190 | 529 | } |
1da177e4 | 530 | |
b2a4df20 DH |
531 | /* skip invalidated, revoked and expired keys */ |
532 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
533 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | | |
534 | (1 << KEY_FLAG_REVOKED))) { | |
535 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
536 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
537 | goto skipped; | |
538 | } | |
1da177e4 | 539 | |
b2a4df20 DH |
540 | if (key->expiry && ctx->now.tv_sec >= key->expiry) { |
541 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
542 | kleave(" = %d [expire]", ctx->skipped_ret); | |
543 | goto skipped; | |
544 | } | |
545 | } | |
664cceb0 | 546 | |
b2a4df20 | 547 | /* keys that don't match */ |
46291959 | 548 | if (!ctx->match_data.cmp(key, &ctx->match_data)) { |
b2a4df20 DH |
549 | kleave(" = 0 [!match]"); |
550 | return 0; | |
551 | } | |
dceba994 | 552 | |
b2a4df20 DH |
553 | /* key must have search permissions */ |
554 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
555 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 556 | ctx->cred, KEY_NEED_SEARCH) < 0) { |
b2a4df20 DH |
557 | ctx->result = ERR_PTR(-EACCES); |
558 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
559 | goto skipped; | |
dceba994 KC |
560 | } |
561 | ||
b2a4df20 DH |
562 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
563 | /* we set a different error code if we pass a negative key */ | |
564 | if (kflags & (1 << KEY_FLAG_NEGATIVE)) { | |
74792b00 | 565 | smp_rmb(); |
b2a4df20 DH |
566 | ctx->result = ERR_PTR(key->type_data.reject_error); |
567 | kleave(" = %d [neg]", ctx->skipped_ret); | |
568 | goto skipped; | |
569 | } | |
570 | } | |
1da177e4 | 571 | |
b2a4df20 DH |
572 | /* Found */ |
573 | ctx->result = make_key_ref(key, ctx->possessed); | |
574 | kleave(" = 1 [found]"); | |
575 | return 1; | |
1da177e4 | 576 | |
b2a4df20 DH |
577 | skipped: |
578 | return ctx->skipped_ret; | |
579 | } | |
1da177e4 | 580 | |
b2a4df20 DH |
581 | /* |
582 | * Search inside a keyring for a key. We can search by walking to it | |
583 | * directly based on its index-key or we can iterate over the entire | |
584 | * tree looking for it, based on the match function. | |
585 | */ | |
586 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
587 | { | |
46291959 | 588 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { |
b2a4df20 DH |
589 | const void *object; |
590 | ||
591 | object = assoc_array_find(&keyring->keys, | |
592 | &keyring_assoc_array_ops, | |
593 | &ctx->index_key); | |
594 | return object ? ctx->iterator(object, ctx) : 0; | |
595 | } | |
596 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
597 | } | |
1da177e4 | 598 | |
b2a4df20 DH |
599 | /* |
600 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
601 | * depth. | |
602 | */ | |
603 | static bool search_nested_keyrings(struct key *keyring, | |
604 | struct keyring_search_context *ctx) | |
605 | { | |
606 | struct { | |
607 | struct key *keyring; | |
608 | struct assoc_array_node *node; | |
609 | int slot; | |
610 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 611 | |
b2a4df20 DH |
612 | struct assoc_array_shortcut *shortcut; |
613 | struct assoc_array_node *node; | |
614 | struct assoc_array_ptr *ptr; | |
615 | struct key *key; | |
616 | int sp = 0, slot; | |
1da177e4 | 617 | |
b2a4df20 DH |
618 | kenter("{%d},{%s,%s}", |
619 | keyring->serial, | |
620 | ctx->index_key.type->name, | |
621 | ctx->index_key.description); | |
1da177e4 | 622 | |
b2a4df20 DH |
623 | if (ctx->index_key.description) |
624 | ctx->index_key.desc_len = strlen(ctx->index_key.description); | |
1da177e4 | 625 | |
b2a4df20 DH |
626 | /* Check to see if this top-level keyring is what we are looking for |
627 | * and whether it is valid or not. | |
628 | */ | |
46291959 | 629 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || |
b2a4df20 DH |
630 | keyring_compare_object(keyring, &ctx->index_key)) { |
631 | ctx->skipped_ret = 2; | |
632 | ctx->flags |= KEYRING_SEARCH_DO_STATE_CHECK; | |
633 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { | |
634 | case 1: | |
78b7280c | 635 | goto found; |
b2a4df20 DH |
636 | case 2: |
637 | return false; | |
638 | default: | |
639 | break; | |
1da177e4 | 640 | } |
b2a4df20 | 641 | } |
1da177e4 | 642 | |
b2a4df20 DH |
643 | ctx->skipped_ret = 0; |
644 | if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) | |
645 | ctx->flags &= ~KEYRING_SEARCH_DO_STATE_CHECK; | |
646 | ||
647 | /* Start processing a new keyring */ | |
648 | descend_to_keyring: | |
649 | kdebug("descend to %d", keyring->serial); | |
650 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
651 | (1 << KEY_FLAG_REVOKED))) | |
652 | goto not_this_keyring; | |
653 | ||
654 | /* Search through the keys in this keyring before its searching its | |
655 | * subtrees. | |
656 | */ | |
657 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 658 | goto found; |
1da177e4 | 659 | |
b2a4df20 DH |
660 | /* Then manually iterate through the keyrings nested in this one. |
661 | * | |
662 | * Start from the root node of the index tree. Because of the way the | |
663 | * hash function has been set up, keyrings cluster on the leftmost | |
664 | * branch of the root node (root slot 0) or in the root node itself. | |
665 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
666 | * slots 1-15). | |
667 | */ | |
668 | ptr = ACCESS_ONCE(keyring->keys.root); | |
669 | if (!ptr) | |
670 | goto not_this_keyring; | |
1da177e4 | 671 | |
b2a4df20 DH |
672 | if (assoc_array_ptr_is_shortcut(ptr)) { |
673 | /* If the root is a shortcut, either the keyring only contains | |
674 | * keyring pointers (everything clusters behind root slot 0) or | |
675 | * doesn't contain any keyring pointers. | |
1da177e4 | 676 | */ |
b2a4df20 DH |
677 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
678 | smp_read_barrier_depends(); | |
679 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) | |
680 | goto not_this_keyring; | |
681 | ||
682 | ptr = ACCESS_ONCE(shortcut->next_node); | |
683 | node = assoc_array_ptr_to_node(ptr); | |
684 | goto begin_node; | |
685 | } | |
686 | ||
687 | node = assoc_array_ptr_to_node(ptr); | |
688 | smp_read_barrier_depends(); | |
689 | ||
690 | ptr = node->slots[0]; | |
691 | if (!assoc_array_ptr_is_meta(ptr)) | |
692 | goto begin_node; | |
693 | ||
694 | descend_to_node: | |
695 | /* Descend to a more distal node in this keyring's content tree and go | |
696 | * through that. | |
697 | */ | |
698 | kdebug("descend"); | |
699 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
700 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
701 | smp_read_barrier_depends(); | |
702 | ptr = ACCESS_ONCE(shortcut->next_node); | |
703 | BUG_ON(!assoc_array_ptr_is_node(ptr)); | |
b2a4df20 | 704 | } |
9c5e45df | 705 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
706 | |
707 | begin_node: | |
708 | kdebug("begin_node"); | |
709 | smp_read_barrier_depends(); | |
710 | slot = 0; | |
711 | ascend_to_node: | |
712 | /* Go through the slots in a node */ | |
713 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
714 | ptr = ACCESS_ONCE(node->slots[slot]); | |
715 | ||
716 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
717 | goto descend_to_node; | |
718 | ||
719 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 720 | continue; |
1da177e4 | 721 | |
b2a4df20 DH |
722 | key = keyring_ptr_to_key(ptr); |
723 | ||
724 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
725 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
726 | ctx->result = ERR_PTR(-ELOOP); | |
727 | return false; | |
728 | } | |
729 | goto not_this_keyring; | |
730 | } | |
731 | ||
732 | /* Search a nested keyring */ | |
733 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
734 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 735 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 736 | continue; |
1da177e4 LT |
737 | |
738 | /* stack the current position */ | |
31d5a79d | 739 | stack[sp].keyring = keyring; |
b2a4df20 DH |
740 | stack[sp].node = node; |
741 | stack[sp].slot = slot; | |
1da177e4 LT |
742 | sp++; |
743 | ||
744 | /* begin again with the new keyring */ | |
745 | keyring = key; | |
b2a4df20 DH |
746 | goto descend_to_keyring; |
747 | } | |
748 | ||
749 | /* We've dealt with all the slots in the current node, so now we need | |
750 | * to ascend to the parent and continue processing there. | |
751 | */ | |
752 | ptr = ACCESS_ONCE(node->back_pointer); | |
753 | slot = node->parent_slot; | |
754 | ||
755 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
756 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
757 | smp_read_barrier_depends(); | |
758 | ptr = ACCESS_ONCE(shortcut->back_pointer); | |
759 | slot = shortcut->parent_slot; | |
760 | } | |
761 | if (!ptr) | |
762 | goto not_this_keyring; | |
763 | node = assoc_array_ptr_to_node(ptr); | |
764 | smp_read_barrier_depends(); | |
765 | slot++; | |
766 | ||
767 | /* If we've ascended to the root (zero backpointer), we must have just | |
768 | * finished processing the leftmost branch rather than the root slots - | |
769 | * so there can't be any more keyrings for us to find. | |
770 | */ | |
771 | if (node->back_pointer) { | |
772 | kdebug("ascend %d", slot); | |
773 | goto ascend_to_node; | |
1da177e4 LT |
774 | } |
775 | ||
b2a4df20 DH |
776 | /* The keyring we're looking at was disqualified or didn't contain a |
777 | * matching key. | |
778 | */ | |
664cceb0 | 779 | not_this_keyring: |
b2a4df20 DH |
780 | kdebug("not_this_keyring %d", sp); |
781 | if (sp <= 0) { | |
782 | kleave(" = false"); | |
783 | return false; | |
1da177e4 LT |
784 | } |
785 | ||
b2a4df20 DH |
786 | /* Resume the processing of a keyring higher up in the tree */ |
787 | sp--; | |
788 | keyring = stack[sp].keyring; | |
789 | node = stack[sp].node; | |
790 | slot = stack[sp].slot + 1; | |
791 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
792 | goto ascend_to_node; | |
1da177e4 | 793 | |
b2a4df20 | 794 | /* We found a viable match */ |
664cceb0 | 795 | found: |
b2a4df20 | 796 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 797 | key_check(key); |
b2a4df20 DH |
798 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
799 | key->last_used_at = ctx->now.tv_sec; | |
800 | keyring->last_used_at = ctx->now.tv_sec; | |
801 | while (sp > 0) | |
802 | stack[--sp].keyring->last_used_at = ctx->now.tv_sec; | |
803 | } | |
804 | kleave(" = true"); | |
805 | return true; | |
806 | } | |
807 | ||
808 | /** | |
809 | * keyring_search_aux - Search a keyring tree for a key matching some criteria | |
810 | * @keyring_ref: A pointer to the keyring with possession indicator. | |
811 | * @ctx: The keyring search context. | |
812 | * | |
813 | * Search the supplied keyring tree for a key that matches the criteria given. | |
814 | * The root keyring and any linked keyrings must grant Search permission to the | |
815 | * caller to be searchable and keys can only be found if they too grant Search | |
816 | * to the caller. The possession flag on the root keyring pointer controls use | |
817 | * of the possessor bits in permissions checking of the entire tree. In | |
818 | * addition, the LSM gets to forbid keyring searches and key matches. | |
819 | * | |
820 | * The search is performed as a breadth-then-depth search up to the prescribed | |
821 | * limit (KEYRING_SEARCH_MAX_DEPTH). | |
822 | * | |
823 | * Keys are matched to the type provided and are then filtered by the match | |
824 | * function, which is given the description to use in any way it sees fit. The | |
825 | * match function may use any attributes of a key that it wishes to to | |
826 | * determine the match. Normally the match function from the key type would be | |
827 | * used. | |
828 | * | |
829 | * RCU can be used to prevent the keyring key lists from disappearing without | |
830 | * the need to take lots of locks. | |
831 | * | |
832 | * Returns a pointer to the found key and increments the key usage count if | |
833 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
834 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
835 | * specified keyring wasn't a keyring. | |
836 | * | |
837 | * In the case of a successful return, the possession attribute from | |
838 | * @keyring_ref is propagated to the returned key reference. | |
839 | */ | |
840 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, | |
841 | struct keyring_search_context *ctx) | |
842 | { | |
843 | struct key *keyring; | |
844 | long err; | |
845 | ||
846 | ctx->iterator = keyring_search_iterator; | |
847 | ctx->possessed = is_key_possessed(keyring_ref); | |
848 | ctx->result = ERR_PTR(-EAGAIN); | |
849 | ||
850 | keyring = key_ref_to_ptr(keyring_ref); | |
851 | key_check(keyring); | |
852 | ||
853 | if (keyring->type != &key_type_keyring) | |
854 | return ERR_PTR(-ENOTDIR); | |
855 | ||
856 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 857 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
858 | if (err < 0) |
859 | return ERR_PTR(err); | |
860 | } | |
861 | ||
862 | rcu_read_lock(); | |
863 | ctx->now = current_kernel_time(); | |
864 | if (search_nested_keyrings(keyring, ctx)) | |
865 | __key_get(key_ref_to_ptr(ctx->result)); | |
76d8aeab | 866 | rcu_read_unlock(); |
b2a4df20 | 867 | return ctx->result; |
a8b17ed0 | 868 | } |
1da177e4 | 869 | |
973c9f4f DH |
870 | /** |
871 | * keyring_search - Search the supplied keyring tree for a matching key | |
872 | * @keyring: The root of the keyring tree to be searched. | |
873 | * @type: The type of keyring we want to find. | |
874 | * @description: The name of the keyring we want to find. | |
875 | * | |
876 | * As keyring_search_aux() above, but using the current task's credentials and | |
b2a4df20 | 877 | * type's default matching function and preferred search method. |
1da177e4 | 878 | */ |
664cceb0 DH |
879 | key_ref_t keyring_search(key_ref_t keyring, |
880 | struct key_type *type, | |
881 | const char *description) | |
1da177e4 | 882 | { |
4bdf0bc3 DH |
883 | struct keyring_search_context ctx = { |
884 | .index_key.type = type, | |
885 | .index_key.description = description, | |
886 | .cred = current_cred(), | |
46291959 DH |
887 | .match_data.cmp = type->match, |
888 | .match_data.raw_data = description, | |
889 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
890 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 891 | }; |
46291959 DH |
892 | key_ref_t key; |
893 | int ret; | |
4bdf0bc3 | 894 | |
46291959 | 895 | if (!ctx.match_data.cmp) |
3e30148c DH |
896 | return ERR_PTR(-ENOKEY); |
897 | ||
46291959 DH |
898 | if (type->match_preparse) { |
899 | ret = type->match_preparse(&ctx.match_data); | |
900 | if (ret < 0) | |
901 | return ERR_PTR(ret); | |
902 | } | |
903 | ||
904 | key = keyring_search_aux(keyring, &ctx); | |
905 | ||
906 | if (type->match_free) | |
907 | type->match_free(&ctx.match_data); | |
908 | return key; | |
a8b17ed0 | 909 | } |
1da177e4 LT |
910 | EXPORT_SYMBOL(keyring_search); |
911 | ||
1da177e4 | 912 | /* |
b2a4df20 | 913 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
914 | * |
915 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
916 | * permission is granted to modify the keyring as no check is made here. The |
917 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
918 | * |
919 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
920 | * successful and returns NULL if not found. Revoked and invalidated keys are |
921 | * skipped over. | |
973c9f4f DH |
922 | * |
923 | * If successful, the possession indicator is propagated from the keyring ref | |
924 | * to the returned key reference. | |
1da177e4 | 925 | */ |
b2a4df20 DH |
926 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
927 | const struct keyring_index_key *index_key) | |
1da177e4 | 928 | { |
664cceb0 | 929 | struct key *keyring, *key; |
b2a4df20 | 930 | const void *object; |
1da177e4 | 931 | |
664cceb0 | 932 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 933 | |
b2a4df20 DH |
934 | kenter("{%d},{%s,%s}", |
935 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 936 | |
b2a4df20 DH |
937 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
938 | index_key); | |
1da177e4 | 939 | |
b2a4df20 DH |
940 | if (object) |
941 | goto found; | |
942 | ||
943 | kleave(" = NULL"); | |
944 | return NULL; | |
1da177e4 | 945 | |
c5b60b5e | 946 | found: |
b2a4df20 DH |
947 | key = keyring_ptr_to_key(object); |
948 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
949 | (1 << KEY_FLAG_REVOKED))) { | |
950 | kleave(" = NULL [x]"); | |
951 | return NULL; | |
952 | } | |
ccc3e6d9 | 953 | __key_get(key); |
b2a4df20 DH |
954 | kleave(" = {%d}", key->serial); |
955 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 956 | } |
1da177e4 | 957 | |
1da177e4 | 958 | /* |
973c9f4f DH |
959 | * Find a keyring with the specified name. |
960 | * | |
961 | * All named keyrings in the current user namespace are searched, provided they | |
962 | * grant Search permission directly to the caller (unless this check is | |
963 | * skipped). Keyrings whose usage points have reached zero or who have been | |
964 | * revoked are skipped. | |
965 | * | |
966 | * Returns a pointer to the keyring with the keyring's refcount having being | |
967 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 968 | */ |
69664cf1 | 969 | struct key *find_keyring_by_name(const char *name, bool skip_perm_check) |
1da177e4 LT |
970 | { |
971 | struct key *keyring; | |
972 | int bucket; | |
973 | ||
1da177e4 | 974 | if (!name) |
cea7daa3 | 975 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
976 | |
977 | bucket = keyring_hash(name); | |
978 | ||
979 | read_lock(&keyring_name_lock); | |
980 | ||
981 | if (keyring_name_hash[bucket].next) { | |
982 | /* search this hash bucket for a keyring with a matching name | |
983 | * that's readable and that hasn't been revoked */ | |
984 | list_for_each_entry(keyring, | |
985 | &keyring_name_hash[bucket], | |
986 | type_data.link | |
987 | ) { | |
9a56c2db | 988 | if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) |
2ea190d0 SH |
989 | continue; |
990 | ||
76d8aeab | 991 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1da177e4 LT |
992 | continue; |
993 | ||
994 | if (strcmp(keyring->description, name) != 0) | |
995 | continue; | |
996 | ||
69664cf1 DH |
997 | if (!skip_perm_check && |
998 | key_permission(make_key_ref(keyring, 0), | |
f5895943 | 999 | KEY_NEED_SEARCH) < 0) |
1da177e4 LT |
1000 | continue; |
1001 | ||
cea7daa3 TO |
1002 | /* we've got a match but we might end up racing with |
1003 | * key_cleanup() if the keyring is currently 'dead' | |
1004 | * (ie. it has a zero usage count) */ | |
1005 | if (!atomic_inc_not_zero(&keyring->usage)) | |
1006 | continue; | |
31d5a79d | 1007 | keyring->last_used_at = current_kernel_time().tv_sec; |
cea7daa3 | 1008 | goto out; |
1da177e4 LT |
1009 | } |
1010 | } | |
1011 | ||
1da177e4 | 1012 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1013 | out: |
1014 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1015 | return keyring; |
a8b17ed0 | 1016 | } |
1da177e4 | 1017 | |
b2a4df20 DH |
1018 | static int keyring_detect_cycle_iterator(const void *object, |
1019 | void *iterator_data) | |
1020 | { | |
1021 | struct keyring_search_context *ctx = iterator_data; | |
1022 | const struct key *key = keyring_ptr_to_key(object); | |
1023 | ||
1024 | kenter("{%d}", key->serial); | |
1025 | ||
979e0d74 DH |
1026 | /* We might get a keyring with matching index-key that is nonetheless a |
1027 | * different keyring. */ | |
46291959 | 1028 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1029 | return 0; |
1030 | ||
b2a4df20 DH |
1031 | ctx->result = ERR_PTR(-EDEADLK); |
1032 | return 1; | |
1033 | } | |
1034 | ||
1da177e4 | 1035 | /* |
973c9f4f DH |
1036 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1037 | * tree A at the topmost level (ie: as a direct child of A). | |
1038 | * | |
1039 | * Since we are adding B to A at the top level, checking for cycles should just | |
1040 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1041 | */ |
1042 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1043 | { | |
b2a4df20 | 1044 | struct keyring_search_context ctx = { |
46291959 DH |
1045 | .index_key = A->index_key, |
1046 | .match_data.raw_data = A, | |
1047 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1048 | .iterator = keyring_detect_cycle_iterator, | |
1049 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1050 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1051 | KEYRING_SEARCH_NO_CHECK_PERM | | |
1052 | KEYRING_SEARCH_DETECT_TOO_DEEP), | |
b2a4df20 | 1053 | }; |
1da177e4 | 1054 | |
76d8aeab | 1055 | rcu_read_lock(); |
b2a4df20 | 1056 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1057 | rcu_read_unlock(); |
b2a4df20 | 1058 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1059 | } |
cab8eb59 | 1060 | |
1da177e4 | 1061 | /* |
973c9f4f | 1062 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1063 | */ |
b2a4df20 DH |
1064 | int __key_link_begin(struct key *keyring, |
1065 | const struct keyring_index_key *index_key, | |
1066 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1067 | __acquires(&keyring->sem) |
423b9788 | 1068 | __acquires(&keyring_serialise_link_sem) |
1da177e4 | 1069 | { |
b2a4df20 DH |
1070 | struct assoc_array_edit *edit; |
1071 | int ret; | |
1da177e4 | 1072 | |
16feef43 | 1073 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1074 | keyring->serial, index_key->type->name, index_key->description); |
1075 | ||
1076 | BUG_ON(index_key->desc_len == 0); | |
1da177e4 | 1077 | |
1da177e4 | 1078 | if (keyring->type != &key_type_keyring) |
f70e2e06 DH |
1079 | return -ENOTDIR; |
1080 | ||
1081 | down_write(&keyring->sem); | |
1082 | ||
1083 | ret = -EKEYREVOKED; | |
1084 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
1085 | goto error_krsem; | |
1da177e4 | 1086 | |
f70e2e06 DH |
1087 | /* serialise link/link calls to prevent parallel calls causing a cycle |
1088 | * when linking two keyring in opposite orders */ | |
16feef43 | 1089 | if (index_key->type == &key_type_keyring) |
553d603c DH |
1090 | down_write(&keyring_serialise_link_sem); |
1091 | ||
b2a4df20 DH |
1092 | /* Create an edit script that will insert/replace the key in the |
1093 | * keyring tree. | |
1094 | */ | |
1095 | edit = assoc_array_insert(&keyring->keys, | |
1096 | &keyring_assoc_array_ops, | |
1097 | index_key, | |
1098 | NULL); | |
1099 | if (IS_ERR(edit)) { | |
1100 | ret = PTR_ERR(edit); | |
034faeb9 DH |
1101 | goto error_sem; |
1102 | } | |
1103 | ||
1104 | /* If we're not replacing a link in-place then we're going to need some | |
1105 | * extra quota. | |
1106 | */ | |
1107 | if (!edit->dead_leaf) { | |
1108 | ret = key_payload_reserve(keyring, | |
1109 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1110 | if (ret < 0) | |
1111 | goto error_cancel; | |
1da177e4 LT |
1112 | } |
1113 | ||
b2a4df20 | 1114 | *_edit = edit; |
f70e2e06 DH |
1115 | kleave(" = 0"); |
1116 | return 0; | |
1da177e4 | 1117 | |
034faeb9 DH |
1118 | error_cancel: |
1119 | assoc_array_cancel_edit(edit); | |
f70e2e06 | 1120 | error_sem: |
16feef43 | 1121 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1122 | up_write(&keyring_serialise_link_sem); |
1123 | error_krsem: | |
1124 | up_write(&keyring->sem); | |
1125 | kleave(" = %d", ret); | |
1126 | return ret; | |
1127 | } | |
1da177e4 | 1128 | |
f70e2e06 | 1129 | /* |
973c9f4f DH |
1130 | * Check already instantiated keys aren't going to be a problem. |
1131 | * | |
1132 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1133 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1134 | */ |
1135 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1136 | { | |
1137 | if (key->type == &key_type_keyring) | |
1138 | /* check that we aren't going to create a cycle by linking one | |
1139 | * keyring to another */ | |
1140 | return keyring_detect_cycle(keyring, key); | |
1141 | return 0; | |
1142 | } | |
1143 | ||
1144 | /* | |
973c9f4f DH |
1145 | * Link a key into to a keyring. |
1146 | * | |
1147 | * Must be called with __key_link_begin() having being called. Discards any | |
1148 | * already extant link to matching key if there is one, so that each keyring | |
1149 | * holds at most one link to any given key of a particular type+description | |
1150 | * combination. | |
f70e2e06 | 1151 | */ |
b2a4df20 | 1152 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1153 | { |
ccc3e6d9 | 1154 | __key_get(key); |
b2a4df20 DH |
1155 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1156 | assoc_array_apply_edit(*_edit); | |
1157 | *_edit = NULL; | |
f70e2e06 DH |
1158 | } |
1159 | ||
1160 | /* | |
973c9f4f DH |
1161 | * Finish linking a key into to a keyring. |
1162 | * | |
1163 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1164 | */ |
16feef43 DH |
1165 | void __key_link_end(struct key *keyring, |
1166 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1167 | struct assoc_array_edit *edit) |
f70e2e06 | 1168 | __releases(&keyring->sem) |
423b9788 | 1169 | __releases(&keyring_serialise_link_sem) |
f70e2e06 | 1170 | { |
16feef43 | 1171 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1172 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1173 | |
16feef43 | 1174 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1175 | up_write(&keyring_serialise_link_sem); |
1176 | ||
034faeb9 | 1177 | if (edit && !edit->dead_leaf) { |
b2a4df20 DH |
1178 | key_payload_reserve(keyring, |
1179 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1180 | assoc_array_cancel_edit(edit); | |
f70e2e06 DH |
1181 | } |
1182 | up_write(&keyring->sem); | |
1183 | } | |
1da177e4 | 1184 | |
973c9f4f DH |
1185 | /** |
1186 | * key_link - Link a key to a keyring | |
1187 | * @keyring: The keyring to make the link in. | |
1188 | * @key: The key to link to. | |
1189 | * | |
1190 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1191 | * on that key and the key can potentially be found by searching that keyring. | |
1192 | * | |
1193 | * This function will write-lock the keyring's semaphore and will consume some | |
1194 | * of the user's key data quota to hold the link. | |
1195 | * | |
1196 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1197 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1198 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1199 | * another link or -ENOMEM if there's insufficient memory. | |
1200 | * | |
1201 | * It is assumed that the caller has checked that it is permitted for a link to | |
1202 | * be made (the keyring should have Write permission and the key Link | |
1203 | * permission). | |
1da177e4 LT |
1204 | */ |
1205 | int key_link(struct key *keyring, struct key *key) | |
1206 | { | |
b2a4df20 | 1207 | struct assoc_array_edit *edit; |
1da177e4 LT |
1208 | int ret; |
1209 | ||
b2a4df20 DH |
1210 | kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage)); |
1211 | ||
1da177e4 LT |
1212 | key_check(keyring); |
1213 | key_check(key); | |
1214 | ||
008643b8 DH |
1215 | if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) && |
1216 | !test_bit(KEY_FLAG_TRUSTED, &key->flags)) | |
1217 | return -EPERM; | |
1218 | ||
b2a4df20 | 1219 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
f70e2e06 | 1220 | if (ret == 0) { |
b2a4df20 | 1221 | kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage)); |
f70e2e06 DH |
1222 | ret = __key_link_check_live_key(keyring, key); |
1223 | if (ret == 0) | |
b2a4df20 DH |
1224 | __key_link(key, &edit); |
1225 | __key_link_end(keyring, &key->index_key, edit); | |
f70e2e06 | 1226 | } |
1da177e4 | 1227 | |
b2a4df20 | 1228 | kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage)); |
1da177e4 | 1229 | return ret; |
f70e2e06 | 1230 | } |
1da177e4 LT |
1231 | EXPORT_SYMBOL(key_link); |
1232 | ||
973c9f4f DH |
1233 | /** |
1234 | * key_unlink - Unlink the first link to a key from a keyring. | |
1235 | * @keyring: The keyring to remove the link from. | |
1236 | * @key: The key the link is to. | |
1237 | * | |
1238 | * Remove a link from a keyring to a key. | |
1239 | * | |
1240 | * This function will write-lock the keyring's semaphore. | |
1241 | * | |
1242 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1243 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1244 | * memory. | |
1245 | * | |
1246 | * It is assumed that the caller has checked that it is permitted for a link to | |
1247 | * be removed (the keyring should have Write permission; no permissions are | |
1248 | * required on the key). | |
1da177e4 LT |
1249 | */ |
1250 | int key_unlink(struct key *keyring, struct key *key) | |
1251 | { | |
b2a4df20 DH |
1252 | struct assoc_array_edit *edit; |
1253 | int ret; | |
1da177e4 LT |
1254 | |
1255 | key_check(keyring); | |
1256 | key_check(key); | |
1257 | ||
1da177e4 | 1258 | if (keyring->type != &key_type_keyring) |
b2a4df20 | 1259 | return -ENOTDIR; |
1da177e4 LT |
1260 | |
1261 | down_write(&keyring->sem); | |
1262 | ||
b2a4df20 DH |
1263 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, |
1264 | &key->index_key); | |
1265 | if (IS_ERR(edit)) { | |
1266 | ret = PTR_ERR(edit); | |
1267 | goto error; | |
1da177e4 | 1268 | } |
1da177e4 | 1269 | ret = -ENOENT; |
b2a4df20 DH |
1270 | if (edit == NULL) |
1271 | goto error; | |
1da177e4 | 1272 | |
b2a4df20 | 1273 | assoc_array_apply_edit(edit); |
034faeb9 | 1274 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); |
1da177e4 LT |
1275 | ret = 0; |
1276 | ||
76d8aeab | 1277 | error: |
76d8aeab | 1278 | up_write(&keyring->sem); |
b2a4df20 | 1279 | return ret; |
a8b17ed0 | 1280 | } |
1da177e4 LT |
1281 | EXPORT_SYMBOL(key_unlink); |
1282 | ||
973c9f4f DH |
1283 | /** |
1284 | * keyring_clear - Clear a keyring | |
1285 | * @keyring: The keyring to clear. | |
1286 | * | |
1287 | * Clear the contents of the specified keyring. | |
1288 | * | |
1289 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1290 | */ |
1291 | int keyring_clear(struct key *keyring) | |
1292 | { | |
b2a4df20 | 1293 | struct assoc_array_edit *edit; |
76d8aeab | 1294 | int ret; |
1da177e4 | 1295 | |
b2a4df20 DH |
1296 | if (keyring->type != &key_type_keyring) |
1297 | return -ENOTDIR; | |
1da177e4 | 1298 | |
b2a4df20 | 1299 | down_write(&keyring->sem); |
1da177e4 | 1300 | |
b2a4df20 DH |
1301 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1302 | if (IS_ERR(edit)) { | |
1303 | ret = PTR_ERR(edit); | |
1304 | } else { | |
1305 | if (edit) | |
1306 | assoc_array_apply_edit(edit); | |
1307 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1308 | ret = 0; |
1309 | } | |
1310 | ||
b2a4df20 | 1311 | up_write(&keyring->sem); |
1da177e4 | 1312 | return ret; |
a8b17ed0 | 1313 | } |
1da177e4 | 1314 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1315 | |
31204ed9 | 1316 | /* |
973c9f4f DH |
1317 | * Dispose of the links from a revoked keyring. |
1318 | * | |
1319 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1320 | */ |
1321 | static void keyring_revoke(struct key *keyring) | |
1322 | { | |
b2a4df20 | 1323 | struct assoc_array_edit *edit; |
f0641cba | 1324 | |
b2a4df20 DH |
1325 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1326 | if (!IS_ERR(edit)) { | |
1327 | if (edit) | |
1328 | assoc_array_apply_edit(edit); | |
1329 | key_payload_reserve(keyring, 0); | |
1330 | } | |
1331 | } | |
31204ed9 | 1332 | |
62fe3182 | 1333 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1334 | { |
1335 | struct key *key = keyring_ptr_to_key(object); | |
1336 | time_t *limit = iterator_data; | |
31204ed9 | 1337 | |
b2a4df20 DH |
1338 | if (key_is_dead(key, *limit)) |
1339 | return false; | |
1340 | key_get(key); | |
1341 | return true; | |
a8b17ed0 | 1342 | } |
5d135440 | 1343 | |
62fe3182 DH |
1344 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1345 | { | |
1346 | const struct key *key = keyring_ptr_to_key(object); | |
1347 | time_t *limit = iterator_data; | |
1348 | ||
1349 | key_check(key); | |
1350 | return key_is_dead(key, *limit); | |
1351 | } | |
1352 | ||
5d135440 | 1353 | /* |
62fe3182 | 1354 | * Garbage collect pointers from a keyring. |
973c9f4f | 1355 | * |
62fe3182 DH |
1356 | * Not called with any locks held. The keyring's key struct will not be |
1357 | * deallocated under us as only our caller may deallocate it. | |
5d135440 DH |
1358 | */ |
1359 | void keyring_gc(struct key *keyring, time_t limit) | |
1360 | { | |
62fe3182 DH |
1361 | int result; |
1362 | ||
1363 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1364 | |
62fe3182 DH |
1365 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1366 | (1 << KEY_FLAG_REVOKED))) | |
1367 | goto dont_gc; | |
1368 | ||
1369 | /* scan the keyring looking for dead keys */ | |
1370 | rcu_read_lock(); | |
1371 | result = assoc_array_iterate(&keyring->keys, | |
1372 | keyring_gc_check_iterator, &limit); | |
1373 | rcu_read_unlock(); | |
1374 | if (result == true) | |
1375 | goto do_gc; | |
1376 | ||
1377 | dont_gc: | |
1378 | kleave(" [no gc]"); | |
1379 | return; | |
1380 | ||
1381 | do_gc: | |
5d135440 | 1382 | down_write(&keyring->sem); |
b2a4df20 | 1383 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1384 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1385 | up_write(&keyring->sem); |
62fe3182 | 1386 | kleave(" [gc]"); |
5d135440 | 1387 | } |