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 LT |
75 | */ |
76 | static int keyring_instantiate(struct key *keyring, | |
cf7f601c | 77 | struct key_preparsed_payload *prep); |
31204ed9 | 78 | static void keyring_revoke(struct key *keyring); |
1da177e4 LT |
79 | static void keyring_destroy(struct key *keyring); |
80 | static void keyring_describe(const struct key *keyring, struct seq_file *m); | |
81 | static long keyring_read(const struct key *keyring, | |
82 | char __user *buffer, size_t buflen); | |
83 | ||
84 | struct key_type key_type_keyring = { | |
85 | .name = "keyring", | |
b2a4df20 | 86 | .def_datalen = 0, |
1da177e4 | 87 | .instantiate = keyring_instantiate, |
b2a4df20 | 88 | .match = user_match, |
31204ed9 | 89 | .revoke = keyring_revoke, |
1da177e4 LT |
90 | .destroy = keyring_destroy, |
91 | .describe = keyring_describe, | |
92 | .read = keyring_read, | |
93 | }; | |
7318226e DH |
94 | EXPORT_SYMBOL(key_type_keyring); |
95 | ||
1da177e4 | 96 | /* |
973c9f4f DH |
97 | * Semaphore to serialise link/link calls to prevent two link calls in parallel |
98 | * introducing a cycle. | |
1da177e4 | 99 | */ |
1ae8f407 | 100 | static DECLARE_RWSEM(keyring_serialise_link_sem); |
1da177e4 | 101 | |
1da177e4 | 102 | /* |
973c9f4f DH |
103 | * Publish the name of a keyring so that it can be found by name (if it has |
104 | * one). | |
1da177e4 | 105 | */ |
69664cf1 | 106 | static void keyring_publish_name(struct key *keyring) |
1da177e4 LT |
107 | { |
108 | int bucket; | |
109 | ||
110 | if (keyring->description) { | |
111 | bucket = keyring_hash(keyring->description); | |
112 | ||
113 | write_lock(&keyring_name_lock); | |
114 | ||
115 | if (!keyring_name_hash[bucket].next) | |
116 | INIT_LIST_HEAD(&keyring_name_hash[bucket]); | |
117 | ||
118 | list_add_tail(&keyring->type_data.link, | |
119 | &keyring_name_hash[bucket]); | |
120 | ||
121 | write_unlock(&keyring_name_lock); | |
122 | } | |
a8b17ed0 | 123 | } |
1da177e4 | 124 | |
1da177e4 | 125 | /* |
973c9f4f DH |
126 | * Initialise a keyring. |
127 | * | |
128 | * Returns 0 on success, -EINVAL if given any data. | |
1da177e4 LT |
129 | */ |
130 | static int keyring_instantiate(struct key *keyring, | |
cf7f601c | 131 | struct key_preparsed_payload *prep) |
1da177e4 LT |
132 | { |
133 | int ret; | |
134 | ||
135 | ret = -EINVAL; | |
cf7f601c | 136 | if (prep->datalen == 0) { |
b2a4df20 | 137 | assoc_array_init(&keyring->keys); |
1da177e4 LT |
138 | /* make the keyring available by name if it has one */ |
139 | keyring_publish_name(keyring); | |
140 | ret = 0; | |
141 | } | |
142 | ||
143 | return ret; | |
a8b17ed0 | 144 | } |
1da177e4 | 145 | |
1da177e4 | 146 | /* |
b2a4df20 DH |
147 | * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd |
148 | * fold the carry back too, but that requires inline asm. | |
149 | */ | |
150 | static u64 mult_64x32_and_fold(u64 x, u32 y) | |
151 | { | |
152 | u64 hi = (u64)(u32)(x >> 32) * y; | |
153 | u64 lo = (u64)(u32)(x) * y; | |
154 | return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); | |
155 | } | |
156 | ||
157 | /* | |
158 | * Hash a key type and description. | |
159 | */ | |
160 | static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key) | |
161 | { | |
162 | const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; | |
163 | const unsigned long level_mask = ASSOC_ARRAY_LEVEL_STEP_MASK; | |
164 | const char *description = index_key->description; | |
165 | unsigned long hash, type; | |
166 | u32 piece; | |
167 | u64 acc; | |
168 | int n, desc_len = index_key->desc_len; | |
169 | ||
170 | type = (unsigned long)index_key->type; | |
171 | ||
172 | acc = mult_64x32_and_fold(type, desc_len + 13); | |
173 | acc = mult_64x32_and_fold(acc, 9207); | |
174 | for (;;) { | |
175 | n = desc_len; | |
176 | if (n <= 0) | |
177 | break; | |
178 | if (n > 4) | |
179 | n = 4; | |
180 | piece = 0; | |
181 | memcpy(&piece, description, n); | |
182 | description += n; | |
183 | desc_len -= n; | |
184 | acc = mult_64x32_and_fold(acc, piece); | |
185 | acc = mult_64x32_and_fold(acc, 9207); | |
186 | } | |
187 | ||
188 | /* Fold the hash down to 32 bits if need be. */ | |
189 | hash = acc; | |
190 | if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) | |
191 | hash ^= acc >> 32; | |
192 | ||
193 | /* Squidge all the keyrings into a separate part of the tree to | |
194 | * ordinary keys by making sure the lowest level segment in the hash is | |
195 | * zero for keyrings and non-zero otherwise. | |
196 | */ | |
197 | if (index_key->type != &key_type_keyring && (hash & level_mask) == 0) | |
198 | return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; | |
199 | if (index_key->type == &key_type_keyring && (hash & level_mask) != 0) | |
200 | return (hash + (hash << level_shift)) & ~level_mask; | |
201 | return hash; | |
202 | } | |
203 | ||
204 | /* | |
205 | * Build the next index key chunk. | |
206 | * | |
207 | * On 32-bit systems the index key is laid out as: | |
208 | * | |
209 | * 0 4 5 9... | |
210 | * hash desclen typeptr desc[] | |
211 | * | |
212 | * On 64-bit systems: | |
213 | * | |
214 | * 0 8 9 17... | |
215 | * hash desclen typeptr desc[] | |
216 | * | |
217 | * We return it one word-sized chunk at a time. | |
1da177e4 | 218 | */ |
b2a4df20 DH |
219 | static unsigned long keyring_get_key_chunk(const void *data, int level) |
220 | { | |
221 | const struct keyring_index_key *index_key = data; | |
222 | unsigned long chunk = 0; | |
223 | long offset = 0; | |
224 | int desc_len = index_key->desc_len, n = sizeof(chunk); | |
225 | ||
226 | level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; | |
227 | switch (level) { | |
228 | case 0: | |
229 | return hash_key_type_and_desc(index_key); | |
230 | case 1: | |
231 | return ((unsigned long)index_key->type << 8) | desc_len; | |
232 | case 2: | |
233 | if (desc_len == 0) | |
234 | return (u8)((unsigned long)index_key->type >> | |
235 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
236 | n--; | |
237 | offset = 1; | |
238 | default: | |
239 | offset += sizeof(chunk) - 1; | |
240 | offset += (level - 3) * sizeof(chunk); | |
241 | if (offset >= desc_len) | |
242 | return 0; | |
243 | desc_len -= offset; | |
244 | if (desc_len > n) | |
245 | desc_len = n; | |
246 | offset += desc_len; | |
247 | do { | |
248 | chunk <<= 8; | |
249 | chunk |= ((u8*)index_key->description)[--offset]; | |
250 | } while (--desc_len > 0); | |
251 | ||
252 | if (level == 2) { | |
253 | chunk <<= 8; | |
254 | chunk |= (u8)((unsigned long)index_key->type >> | |
255 | (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8)); | |
256 | } | |
257 | return chunk; | |
258 | } | |
259 | } | |
260 | ||
261 | static unsigned long keyring_get_object_key_chunk(const void *object, int level) | |
262 | { | |
263 | const struct key *key = keyring_ptr_to_key(object); | |
264 | return keyring_get_key_chunk(&key->index_key, level); | |
265 | } | |
266 | ||
267 | static bool keyring_compare_object(const void *object, const void *data) | |
1da177e4 | 268 | { |
b2a4df20 DH |
269 | const struct keyring_index_key *index_key = data; |
270 | const struct key *key = keyring_ptr_to_key(object); | |
271 | ||
272 | return key->index_key.type == index_key->type && | |
273 | key->index_key.desc_len == index_key->desc_len && | |
274 | memcmp(key->index_key.description, index_key->description, | |
275 | index_key->desc_len) == 0; | |
a8b17ed0 | 276 | } |
1da177e4 | 277 | |
b2a4df20 DH |
278 | /* |
279 | * Compare the index keys of a pair of objects and determine the bit position | |
280 | * at which they differ - if they differ. | |
281 | */ | |
282 | static int keyring_diff_objects(const void *_a, const void *_b) | |
283 | { | |
284 | const struct key *key_a = keyring_ptr_to_key(_a); | |
285 | const struct key *key_b = keyring_ptr_to_key(_b); | |
286 | const struct keyring_index_key *a = &key_a->index_key; | |
287 | const struct keyring_index_key *b = &key_b->index_key; | |
288 | unsigned long seg_a, seg_b; | |
289 | int level, i; | |
290 | ||
291 | level = 0; | |
292 | seg_a = hash_key_type_and_desc(a); | |
293 | seg_b = hash_key_type_and_desc(b); | |
294 | if ((seg_a ^ seg_b) != 0) | |
295 | goto differ; | |
296 | ||
297 | /* The number of bits contributed by the hash is controlled by a | |
298 | * constant in the assoc_array headers. Everything else thereafter we | |
299 | * can deal with as being machine word-size dependent. | |
300 | */ | |
301 | level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; | |
302 | seg_a = a->desc_len; | |
303 | seg_b = b->desc_len; | |
304 | if ((seg_a ^ seg_b) != 0) | |
305 | goto differ; | |
306 | ||
307 | /* The next bit may not work on big endian */ | |
308 | level++; | |
309 | seg_a = (unsigned long)a->type; | |
310 | seg_b = (unsigned long)b->type; | |
311 | if ((seg_a ^ seg_b) != 0) | |
312 | goto differ; | |
313 | ||
314 | level += sizeof(unsigned long); | |
315 | if (a->desc_len == 0) | |
316 | goto same; | |
317 | ||
318 | i = 0; | |
319 | if (((unsigned long)a->description | (unsigned long)b->description) & | |
320 | (sizeof(unsigned long) - 1)) { | |
321 | do { | |
322 | seg_a = *(unsigned long *)(a->description + i); | |
323 | seg_b = *(unsigned long *)(b->description + i); | |
324 | if ((seg_a ^ seg_b) != 0) | |
325 | goto differ_plus_i; | |
326 | i += sizeof(unsigned long); | |
327 | } while (i < (a->desc_len & (sizeof(unsigned long) - 1))); | |
328 | } | |
329 | ||
330 | for (; i < a->desc_len; i++) { | |
331 | seg_a = *(unsigned char *)(a->description + i); | |
332 | seg_b = *(unsigned char *)(b->description + i); | |
333 | if ((seg_a ^ seg_b) != 0) | |
334 | goto differ_plus_i; | |
335 | } | |
336 | ||
337 | same: | |
338 | return -1; | |
339 | ||
340 | differ_plus_i: | |
341 | level += i; | |
342 | differ: | |
343 | i = level * 8 + __ffs(seg_a ^ seg_b); | |
344 | return i; | |
345 | } | |
346 | ||
347 | /* | |
348 | * Free an object after stripping the keyring flag off of the pointer. | |
349 | */ | |
350 | static void keyring_free_object(void *object) | |
351 | { | |
352 | key_put(keyring_ptr_to_key(object)); | |
353 | } | |
354 | ||
355 | /* | |
356 | * Operations for keyring management by the index-tree routines. | |
357 | */ | |
358 | static const struct assoc_array_ops keyring_assoc_array_ops = { | |
359 | .get_key_chunk = keyring_get_key_chunk, | |
360 | .get_object_key_chunk = keyring_get_object_key_chunk, | |
361 | .compare_object = keyring_compare_object, | |
362 | .diff_objects = keyring_diff_objects, | |
363 | .free_object = keyring_free_object, | |
364 | }; | |
365 | ||
1da177e4 | 366 | /* |
973c9f4f DH |
367 | * Clean up a keyring when it is destroyed. Unpublish its name if it had one |
368 | * and dispose of its data. | |
233e4735 DH |
369 | * |
370 | * The garbage collector detects the final key_put(), removes the keyring from | |
371 | * the serial number tree and then does RCU synchronisation before coming here, | |
372 | * so we shouldn't need to worry about code poking around here with the RCU | |
373 | * readlock held by this time. | |
1da177e4 LT |
374 | */ |
375 | static void keyring_destroy(struct key *keyring) | |
376 | { | |
1da177e4 LT |
377 | if (keyring->description) { |
378 | write_lock(&keyring_name_lock); | |
94efe72f DH |
379 | |
380 | if (keyring->type_data.link.next != NULL && | |
381 | !list_empty(&keyring->type_data.link)) | |
382 | list_del(&keyring->type_data.link); | |
383 | ||
1da177e4 LT |
384 | write_unlock(&keyring_name_lock); |
385 | } | |
386 | ||
b2a4df20 | 387 | assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); |
a8b17ed0 | 388 | } |
1da177e4 | 389 | |
1da177e4 | 390 | /* |
973c9f4f | 391 | * Describe a keyring for /proc. |
1da177e4 LT |
392 | */ |
393 | static void keyring_describe(const struct key *keyring, struct seq_file *m) | |
394 | { | |
c8563473 | 395 | if (keyring->description) |
1da177e4 | 396 | seq_puts(m, keyring->description); |
c8563473 | 397 | else |
1da177e4 | 398 | seq_puts(m, "[anon]"); |
1da177e4 | 399 | |
78b7280c | 400 | if (key_is_instantiated(keyring)) { |
b2a4df20 DH |
401 | if (keyring->keys.nr_leaves_on_tree != 0) |
402 | seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); | |
78b7280c DH |
403 | else |
404 | seq_puts(m, ": empty"); | |
78b7280c | 405 | } |
a8b17ed0 | 406 | } |
1da177e4 | 407 | |
b2a4df20 DH |
408 | struct keyring_read_iterator_context { |
409 | size_t qty; | |
410 | size_t count; | |
411 | key_serial_t __user *buffer; | |
412 | }; | |
413 | ||
414 | static int keyring_read_iterator(const void *object, void *data) | |
415 | { | |
416 | struct keyring_read_iterator_context *ctx = data; | |
417 | const struct key *key = keyring_ptr_to_key(object); | |
418 | int ret; | |
419 | ||
420 | kenter("{%s,%d},,{%zu/%zu}", | |
421 | key->type->name, key->serial, ctx->count, ctx->qty); | |
422 | ||
423 | if (ctx->count >= ctx->qty) | |
424 | return 1; | |
425 | ||
426 | ret = put_user(key->serial, ctx->buffer); | |
427 | if (ret < 0) | |
428 | return ret; | |
429 | ctx->buffer++; | |
430 | ctx->count += sizeof(key->serial); | |
431 | return 0; | |
432 | } | |
433 | ||
1da177e4 | 434 | /* |
973c9f4f DH |
435 | * Read a list of key IDs from the keyring's contents in binary form |
436 | * | |
b2a4df20 DH |
437 | * The keyring's semaphore is read-locked by the caller. This prevents someone |
438 | * from modifying it under us - which could cause us to read key IDs multiple | |
439 | * times. | |
1da177e4 LT |
440 | */ |
441 | static long keyring_read(const struct key *keyring, | |
442 | char __user *buffer, size_t buflen) | |
443 | { | |
b2a4df20 DH |
444 | struct keyring_read_iterator_context ctx; |
445 | unsigned long nr_keys; | |
446 | int ret; | |
1da177e4 | 447 | |
b2a4df20 DH |
448 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
449 | ||
450 | if (buflen & (sizeof(key_serial_t) - 1)) | |
451 | return -EINVAL; | |
452 | ||
453 | nr_keys = keyring->keys.nr_leaves_on_tree; | |
454 | if (nr_keys == 0) | |
455 | return 0; | |
1da177e4 | 456 | |
b2a4df20 DH |
457 | /* Calculate how much data we could return */ |
458 | ctx.qty = nr_keys * sizeof(key_serial_t); | |
459 | ||
460 | if (!buffer || !buflen) | |
461 | return ctx.qty; | |
462 | ||
463 | if (buflen > ctx.qty) | |
464 | ctx.qty = buflen; | |
465 | ||
466 | /* Copy the IDs of the subscribed keys into the buffer */ | |
467 | ctx.buffer = (key_serial_t __user *)buffer; | |
468 | ctx.count = 0; | |
469 | ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx); | |
470 | if (ret < 0) { | |
471 | kleave(" = %d [iterate]", ret); | |
472 | return ret; | |
1da177e4 LT |
473 | } |
474 | ||
b2a4df20 DH |
475 | kleave(" = %zu [ok]", ctx.count); |
476 | return ctx.count; | |
a8b17ed0 | 477 | } |
1da177e4 | 478 | |
1da177e4 | 479 | /* |
973c9f4f | 480 | * Allocate a keyring and link into the destination keyring. |
1da177e4 | 481 | */ |
9a56c2db | 482 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
96b5c8fe DH |
483 | const struct cred *cred, key_perm_t perm, |
484 | unsigned long flags, struct key *dest) | |
1da177e4 LT |
485 | { |
486 | struct key *keyring; | |
487 | int ret; | |
488 | ||
489 | keyring = key_alloc(&key_type_keyring, description, | |
96b5c8fe | 490 | uid, gid, cred, perm, flags); |
1da177e4 | 491 | if (!IS_ERR(keyring)) { |
3e30148c | 492 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
493 | if (ret < 0) { |
494 | key_put(keyring); | |
495 | keyring = ERR_PTR(ret); | |
496 | } | |
497 | } | |
498 | ||
499 | return keyring; | |
a8b17ed0 | 500 | } |
f8aa23a5 | 501 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 502 | |
b2a4df20 DH |
503 | /* |
504 | * Iteration function to consider each key found. | |
1da177e4 | 505 | */ |
b2a4df20 | 506 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 507 | { |
b2a4df20 DH |
508 | struct keyring_search_context *ctx = iterator_data; |
509 | const struct key *key = keyring_ptr_to_key(object); | |
510 | unsigned long kflags = key->flags; | |
1da177e4 | 511 | |
b2a4df20 | 512 | kenter("{%d}", key->serial); |
1da177e4 | 513 | |
b2a4df20 DH |
514 | /* ignore keys not of this type */ |
515 | if (key->type != ctx->index_key.type) { | |
516 | kleave(" = 0 [!type]"); | |
517 | return 0; | |
29db9190 | 518 | } |
1da177e4 | 519 | |
b2a4df20 DH |
520 | /* skip invalidated, revoked and expired keys */ |
521 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
522 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | | |
523 | (1 << KEY_FLAG_REVOKED))) { | |
524 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
525 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
526 | goto skipped; | |
527 | } | |
1da177e4 | 528 | |
b2a4df20 DH |
529 | if (key->expiry && ctx->now.tv_sec >= key->expiry) { |
530 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
531 | kleave(" = %d [expire]", ctx->skipped_ret); | |
532 | goto skipped; | |
533 | } | |
534 | } | |
664cceb0 | 535 | |
b2a4df20 DH |
536 | /* keys that don't match */ |
537 | if (!ctx->match(key, ctx->match_data)) { | |
538 | kleave(" = 0 [!match]"); | |
539 | return 0; | |
540 | } | |
dceba994 | 541 | |
b2a4df20 DH |
542 | /* key must have search permissions */ |
543 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
544 | key_task_permission(make_key_ref(key, ctx->possessed), | |
545 | ctx->cred, KEY_SEARCH) < 0) { | |
546 | ctx->result = ERR_PTR(-EACCES); | |
547 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
548 | goto skipped; | |
dceba994 KC |
549 | } |
550 | ||
b2a4df20 DH |
551 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
552 | /* we set a different error code if we pass a negative key */ | |
553 | if (kflags & (1 << KEY_FLAG_NEGATIVE)) { | |
74792b00 | 554 | smp_rmb(); |
b2a4df20 DH |
555 | ctx->result = ERR_PTR(key->type_data.reject_error); |
556 | kleave(" = %d [neg]", ctx->skipped_ret); | |
557 | goto skipped; | |
558 | } | |
559 | } | |
1da177e4 | 560 | |
b2a4df20 DH |
561 | /* Found */ |
562 | ctx->result = make_key_ref(key, ctx->possessed); | |
563 | kleave(" = 1 [found]"); | |
564 | return 1; | |
1da177e4 | 565 | |
b2a4df20 DH |
566 | skipped: |
567 | return ctx->skipped_ret; | |
568 | } | |
1da177e4 | 569 | |
b2a4df20 DH |
570 | /* |
571 | * Search inside a keyring for a key. We can search by walking to it | |
572 | * directly based on its index-key or we can iterate over the entire | |
573 | * tree looking for it, based on the match function. | |
574 | */ | |
575 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
576 | { | |
577 | if ((ctx->flags & KEYRING_SEARCH_LOOKUP_TYPE) == | |
578 | KEYRING_SEARCH_LOOKUP_DIRECT) { | |
579 | const void *object; | |
580 | ||
581 | object = assoc_array_find(&keyring->keys, | |
582 | &keyring_assoc_array_ops, | |
583 | &ctx->index_key); | |
584 | return object ? ctx->iterator(object, ctx) : 0; | |
585 | } | |
586 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
587 | } | |
1da177e4 | 588 | |
b2a4df20 DH |
589 | /* |
590 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
591 | * depth. | |
592 | */ | |
593 | static bool search_nested_keyrings(struct key *keyring, | |
594 | struct keyring_search_context *ctx) | |
595 | { | |
596 | struct { | |
597 | struct key *keyring; | |
598 | struct assoc_array_node *node; | |
599 | int slot; | |
600 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 601 | |
b2a4df20 DH |
602 | struct assoc_array_shortcut *shortcut; |
603 | struct assoc_array_node *node; | |
604 | struct assoc_array_ptr *ptr; | |
605 | struct key *key; | |
606 | int sp = 0, slot; | |
1da177e4 | 607 | |
b2a4df20 DH |
608 | kenter("{%d},{%s,%s}", |
609 | keyring->serial, | |
610 | ctx->index_key.type->name, | |
611 | ctx->index_key.description); | |
1da177e4 | 612 | |
b2a4df20 DH |
613 | if (ctx->index_key.description) |
614 | ctx->index_key.desc_len = strlen(ctx->index_key.description); | |
1da177e4 | 615 | |
b2a4df20 DH |
616 | /* Check to see if this top-level keyring is what we are looking for |
617 | * and whether it is valid or not. | |
618 | */ | |
619 | if (ctx->flags & KEYRING_SEARCH_LOOKUP_ITERATE || | |
620 | keyring_compare_object(keyring, &ctx->index_key)) { | |
621 | ctx->skipped_ret = 2; | |
622 | ctx->flags |= KEYRING_SEARCH_DO_STATE_CHECK; | |
623 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { | |
624 | case 1: | |
78b7280c | 625 | goto found; |
b2a4df20 DH |
626 | case 2: |
627 | return false; | |
628 | default: | |
629 | break; | |
1da177e4 | 630 | } |
b2a4df20 | 631 | } |
1da177e4 | 632 | |
b2a4df20 DH |
633 | ctx->skipped_ret = 0; |
634 | if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK) | |
635 | ctx->flags &= ~KEYRING_SEARCH_DO_STATE_CHECK; | |
636 | ||
637 | /* Start processing a new keyring */ | |
638 | descend_to_keyring: | |
639 | kdebug("descend to %d", keyring->serial); | |
640 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
641 | (1 << KEY_FLAG_REVOKED))) | |
642 | goto not_this_keyring; | |
643 | ||
644 | /* Search through the keys in this keyring before its searching its | |
645 | * subtrees. | |
646 | */ | |
647 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 648 | goto found; |
1da177e4 | 649 | |
b2a4df20 DH |
650 | /* Then manually iterate through the keyrings nested in this one. |
651 | * | |
652 | * Start from the root node of the index tree. Because of the way the | |
653 | * hash function has been set up, keyrings cluster on the leftmost | |
654 | * branch of the root node (root slot 0) or in the root node itself. | |
655 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
656 | * slots 1-15). | |
657 | */ | |
658 | ptr = ACCESS_ONCE(keyring->keys.root); | |
659 | if (!ptr) | |
660 | goto not_this_keyring; | |
1da177e4 | 661 | |
b2a4df20 DH |
662 | if (assoc_array_ptr_is_shortcut(ptr)) { |
663 | /* If the root is a shortcut, either the keyring only contains | |
664 | * keyring pointers (everything clusters behind root slot 0) or | |
665 | * doesn't contain any keyring pointers. | |
1da177e4 | 666 | */ |
b2a4df20 DH |
667 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
668 | smp_read_barrier_depends(); | |
669 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) | |
670 | goto not_this_keyring; | |
671 | ||
672 | ptr = ACCESS_ONCE(shortcut->next_node); | |
673 | node = assoc_array_ptr_to_node(ptr); | |
674 | goto begin_node; | |
675 | } | |
676 | ||
677 | node = assoc_array_ptr_to_node(ptr); | |
678 | smp_read_barrier_depends(); | |
679 | ||
680 | ptr = node->slots[0]; | |
681 | if (!assoc_array_ptr_is_meta(ptr)) | |
682 | goto begin_node; | |
683 | ||
684 | descend_to_node: | |
685 | /* Descend to a more distal node in this keyring's content tree and go | |
686 | * through that. | |
687 | */ | |
688 | kdebug("descend"); | |
689 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
690 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
691 | smp_read_barrier_depends(); | |
692 | ptr = ACCESS_ONCE(shortcut->next_node); | |
693 | BUG_ON(!assoc_array_ptr_is_node(ptr)); | |
694 | node = assoc_array_ptr_to_node(ptr); | |
695 | } | |
696 | ||
697 | begin_node: | |
698 | kdebug("begin_node"); | |
699 | smp_read_barrier_depends(); | |
700 | slot = 0; | |
701 | ascend_to_node: | |
702 | /* Go through the slots in a node */ | |
703 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
704 | ptr = ACCESS_ONCE(node->slots[slot]); | |
705 | ||
706 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
707 | goto descend_to_node; | |
708 | ||
709 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 710 | continue; |
1da177e4 | 711 | |
b2a4df20 DH |
712 | key = keyring_ptr_to_key(ptr); |
713 | ||
714 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
715 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
716 | ctx->result = ERR_PTR(-ELOOP); | |
717 | return false; | |
718 | } | |
719 | goto not_this_keyring; | |
720 | } | |
721 | ||
722 | /* Search a nested keyring */ | |
723 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
724 | key_task_permission(make_key_ref(key, ctx->possessed), | |
4bdf0bc3 | 725 | ctx->cred, KEY_SEARCH) < 0) |
76d8aeab | 726 | continue; |
1da177e4 LT |
727 | |
728 | /* stack the current position */ | |
31d5a79d | 729 | stack[sp].keyring = keyring; |
b2a4df20 DH |
730 | stack[sp].node = node; |
731 | stack[sp].slot = slot; | |
1da177e4 LT |
732 | sp++; |
733 | ||
734 | /* begin again with the new keyring */ | |
735 | keyring = key; | |
b2a4df20 DH |
736 | goto descend_to_keyring; |
737 | } | |
738 | ||
739 | /* We've dealt with all the slots in the current node, so now we need | |
740 | * to ascend to the parent and continue processing there. | |
741 | */ | |
742 | ptr = ACCESS_ONCE(node->back_pointer); | |
743 | slot = node->parent_slot; | |
744 | ||
745 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
746 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
747 | smp_read_barrier_depends(); | |
748 | ptr = ACCESS_ONCE(shortcut->back_pointer); | |
749 | slot = shortcut->parent_slot; | |
750 | } | |
751 | if (!ptr) | |
752 | goto not_this_keyring; | |
753 | node = assoc_array_ptr_to_node(ptr); | |
754 | smp_read_barrier_depends(); | |
755 | slot++; | |
756 | ||
757 | /* If we've ascended to the root (zero backpointer), we must have just | |
758 | * finished processing the leftmost branch rather than the root slots - | |
759 | * so there can't be any more keyrings for us to find. | |
760 | */ | |
761 | if (node->back_pointer) { | |
762 | kdebug("ascend %d", slot); | |
763 | goto ascend_to_node; | |
1da177e4 LT |
764 | } |
765 | ||
b2a4df20 DH |
766 | /* The keyring we're looking at was disqualified or didn't contain a |
767 | * matching key. | |
768 | */ | |
664cceb0 | 769 | not_this_keyring: |
b2a4df20 DH |
770 | kdebug("not_this_keyring %d", sp); |
771 | if (sp <= 0) { | |
772 | kleave(" = false"); | |
773 | return false; | |
1da177e4 LT |
774 | } |
775 | ||
b2a4df20 DH |
776 | /* Resume the processing of a keyring higher up in the tree */ |
777 | sp--; | |
778 | keyring = stack[sp].keyring; | |
779 | node = stack[sp].node; | |
780 | slot = stack[sp].slot + 1; | |
781 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
782 | goto ascend_to_node; | |
1da177e4 | 783 | |
b2a4df20 | 784 | /* We found a viable match */ |
664cceb0 | 785 | found: |
b2a4df20 | 786 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 787 | key_check(key); |
b2a4df20 DH |
788 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
789 | key->last_used_at = ctx->now.tv_sec; | |
790 | keyring->last_used_at = ctx->now.tv_sec; | |
791 | while (sp > 0) | |
792 | stack[--sp].keyring->last_used_at = ctx->now.tv_sec; | |
793 | } | |
794 | kleave(" = true"); | |
795 | return true; | |
796 | } | |
797 | ||
798 | /** | |
799 | * keyring_search_aux - Search a keyring tree for a key matching some criteria | |
800 | * @keyring_ref: A pointer to the keyring with possession indicator. | |
801 | * @ctx: The keyring search context. | |
802 | * | |
803 | * Search the supplied keyring tree for a key that matches the criteria given. | |
804 | * The root keyring and any linked keyrings must grant Search permission to the | |
805 | * caller to be searchable and keys can only be found if they too grant Search | |
806 | * to the caller. The possession flag on the root keyring pointer controls use | |
807 | * of the possessor bits in permissions checking of the entire tree. In | |
808 | * addition, the LSM gets to forbid keyring searches and key matches. | |
809 | * | |
810 | * The search is performed as a breadth-then-depth search up to the prescribed | |
811 | * limit (KEYRING_SEARCH_MAX_DEPTH). | |
812 | * | |
813 | * Keys are matched to the type provided and are then filtered by the match | |
814 | * function, which is given the description to use in any way it sees fit. The | |
815 | * match function may use any attributes of a key that it wishes to to | |
816 | * determine the match. Normally the match function from the key type would be | |
817 | * used. | |
818 | * | |
819 | * RCU can be used to prevent the keyring key lists from disappearing without | |
820 | * the need to take lots of locks. | |
821 | * | |
822 | * Returns a pointer to the found key and increments the key usage count if | |
823 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
824 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
825 | * specified keyring wasn't a keyring. | |
826 | * | |
827 | * In the case of a successful return, the possession attribute from | |
828 | * @keyring_ref is propagated to the returned key reference. | |
829 | */ | |
830 | key_ref_t keyring_search_aux(key_ref_t keyring_ref, | |
831 | struct keyring_search_context *ctx) | |
832 | { | |
833 | struct key *keyring; | |
834 | long err; | |
835 | ||
836 | ctx->iterator = keyring_search_iterator; | |
837 | ctx->possessed = is_key_possessed(keyring_ref); | |
838 | ctx->result = ERR_PTR(-EAGAIN); | |
839 | ||
840 | keyring = key_ref_to_ptr(keyring_ref); | |
841 | key_check(keyring); | |
842 | ||
843 | if (keyring->type != &key_type_keyring) | |
844 | return ERR_PTR(-ENOTDIR); | |
845 | ||
846 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
847 | err = key_task_permission(keyring_ref, ctx->cred, KEY_SEARCH); | |
848 | if (err < 0) | |
849 | return ERR_PTR(err); | |
850 | } | |
851 | ||
852 | rcu_read_lock(); | |
853 | ctx->now = current_kernel_time(); | |
854 | if (search_nested_keyrings(keyring, ctx)) | |
855 | __key_get(key_ref_to_ptr(ctx->result)); | |
76d8aeab | 856 | rcu_read_unlock(); |
b2a4df20 | 857 | return ctx->result; |
a8b17ed0 | 858 | } |
1da177e4 | 859 | |
973c9f4f DH |
860 | /** |
861 | * keyring_search - Search the supplied keyring tree for a matching key | |
862 | * @keyring: The root of the keyring tree to be searched. | |
863 | * @type: The type of keyring we want to find. | |
864 | * @description: The name of the keyring we want to find. | |
865 | * | |
866 | * As keyring_search_aux() above, but using the current task's credentials and | |
b2a4df20 | 867 | * type's default matching function and preferred search method. |
1da177e4 | 868 | */ |
664cceb0 DH |
869 | key_ref_t keyring_search(key_ref_t keyring, |
870 | struct key_type *type, | |
871 | const char *description) | |
1da177e4 | 872 | { |
4bdf0bc3 DH |
873 | struct keyring_search_context ctx = { |
874 | .index_key.type = type, | |
875 | .index_key.description = description, | |
876 | .cred = current_cred(), | |
877 | .match = type->match, | |
878 | .match_data = description, | |
879 | .flags = (type->def_lookup_type | | |
880 | KEYRING_SEARCH_DO_STATE_CHECK), | |
881 | }; | |
882 | ||
883 | if (!ctx.match) | |
3e30148c DH |
884 | return ERR_PTR(-ENOKEY); |
885 | ||
4bdf0bc3 | 886 | return keyring_search_aux(keyring, &ctx); |
a8b17ed0 | 887 | } |
1da177e4 LT |
888 | EXPORT_SYMBOL(keyring_search); |
889 | ||
1da177e4 | 890 | /* |
b2a4df20 | 891 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
892 | * |
893 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
894 | * permission is granted to modify the keyring as no check is made here. The |
895 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
896 | * |
897 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
898 | * successful and returns NULL if not found. Revoked and invalidated keys are |
899 | * skipped over. | |
973c9f4f DH |
900 | * |
901 | * If successful, the possession indicator is propagated from the keyring ref | |
902 | * to the returned key reference. | |
1da177e4 | 903 | */ |
b2a4df20 DH |
904 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
905 | const struct keyring_index_key *index_key) | |
1da177e4 | 906 | { |
664cceb0 | 907 | struct key *keyring, *key; |
b2a4df20 | 908 | const void *object; |
1da177e4 | 909 | |
664cceb0 | 910 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 911 | |
b2a4df20 DH |
912 | kenter("{%d},{%s,%s}", |
913 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 914 | |
b2a4df20 DH |
915 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
916 | index_key); | |
1da177e4 | 917 | |
b2a4df20 DH |
918 | if (object) |
919 | goto found; | |
920 | ||
921 | kleave(" = NULL"); | |
922 | return NULL; | |
1da177e4 | 923 | |
c5b60b5e | 924 | found: |
b2a4df20 DH |
925 | key = keyring_ptr_to_key(object); |
926 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
927 | (1 << KEY_FLAG_REVOKED))) { | |
928 | kleave(" = NULL [x]"); | |
929 | return NULL; | |
930 | } | |
ccc3e6d9 | 931 | __key_get(key); |
b2a4df20 DH |
932 | kleave(" = {%d}", key->serial); |
933 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 934 | } |
1da177e4 | 935 | |
1da177e4 | 936 | /* |
973c9f4f DH |
937 | * Find a keyring with the specified name. |
938 | * | |
939 | * All named keyrings in the current user namespace are searched, provided they | |
940 | * grant Search permission directly to the caller (unless this check is | |
941 | * skipped). Keyrings whose usage points have reached zero or who have been | |
942 | * revoked are skipped. | |
943 | * | |
944 | * Returns a pointer to the keyring with the keyring's refcount having being | |
945 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 946 | */ |
69664cf1 | 947 | struct key *find_keyring_by_name(const char *name, bool skip_perm_check) |
1da177e4 LT |
948 | { |
949 | struct key *keyring; | |
950 | int bucket; | |
951 | ||
1da177e4 | 952 | if (!name) |
cea7daa3 | 953 | return ERR_PTR(-EINVAL); |
1da177e4 LT |
954 | |
955 | bucket = keyring_hash(name); | |
956 | ||
957 | read_lock(&keyring_name_lock); | |
958 | ||
959 | if (keyring_name_hash[bucket].next) { | |
960 | /* search this hash bucket for a keyring with a matching name | |
961 | * that's readable and that hasn't been revoked */ | |
962 | list_for_each_entry(keyring, | |
963 | &keyring_name_hash[bucket], | |
964 | type_data.link | |
965 | ) { | |
9a56c2db | 966 | if (!kuid_has_mapping(current_user_ns(), keyring->user->uid)) |
2ea190d0 SH |
967 | continue; |
968 | ||
76d8aeab | 969 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1da177e4 LT |
970 | continue; |
971 | ||
972 | if (strcmp(keyring->description, name) != 0) | |
973 | continue; | |
974 | ||
69664cf1 DH |
975 | if (!skip_perm_check && |
976 | key_permission(make_key_ref(keyring, 0), | |
0f6ed7c2 | 977 | KEY_SEARCH) < 0) |
1da177e4 LT |
978 | continue; |
979 | ||
cea7daa3 TO |
980 | /* we've got a match but we might end up racing with |
981 | * key_cleanup() if the keyring is currently 'dead' | |
982 | * (ie. it has a zero usage count) */ | |
983 | if (!atomic_inc_not_zero(&keyring->usage)) | |
984 | continue; | |
31d5a79d | 985 | keyring->last_used_at = current_kernel_time().tv_sec; |
cea7daa3 | 986 | goto out; |
1da177e4 LT |
987 | } |
988 | } | |
989 | ||
1da177e4 | 990 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
991 | out: |
992 | read_unlock(&keyring_name_lock); | |
1da177e4 | 993 | return keyring; |
a8b17ed0 | 994 | } |
1da177e4 | 995 | |
b2a4df20 DH |
996 | static int keyring_detect_cycle_iterator(const void *object, |
997 | void *iterator_data) | |
998 | { | |
999 | struct keyring_search_context *ctx = iterator_data; | |
1000 | const struct key *key = keyring_ptr_to_key(object); | |
1001 | ||
1002 | kenter("{%d}", key->serial); | |
1003 | ||
1004 | BUG_ON(key != ctx->match_data); | |
1005 | ctx->result = ERR_PTR(-EDEADLK); | |
1006 | return 1; | |
1007 | } | |
1008 | ||
1da177e4 | 1009 | /* |
973c9f4f DH |
1010 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1011 | * tree A at the topmost level (ie: as a direct child of A). | |
1012 | * | |
1013 | * Since we are adding B to A at the top level, checking for cycles should just | |
1014 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1015 | */ |
1016 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1017 | { | |
b2a4df20 DH |
1018 | struct keyring_search_context ctx = { |
1019 | .index_key = A->index_key, | |
1020 | .match_data = A, | |
1021 | .iterator = keyring_detect_cycle_iterator, | |
1022 | .flags = (KEYRING_SEARCH_LOOKUP_DIRECT | | |
1023 | KEYRING_SEARCH_NO_STATE_CHECK | | |
1024 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1025 | KEYRING_SEARCH_NO_CHECK_PERM | | |
1026 | KEYRING_SEARCH_DETECT_TOO_DEEP), | |
1027 | }; | |
1da177e4 | 1028 | |
76d8aeab | 1029 | rcu_read_lock(); |
b2a4df20 | 1030 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1031 | rcu_read_unlock(); |
b2a4df20 | 1032 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1033 | } |
cab8eb59 | 1034 | |
1da177e4 | 1035 | /* |
973c9f4f | 1036 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1037 | */ |
b2a4df20 DH |
1038 | int __key_link_begin(struct key *keyring, |
1039 | const struct keyring_index_key *index_key, | |
1040 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1041 | __acquires(&keyring->sem) |
423b9788 | 1042 | __acquires(&keyring_serialise_link_sem) |
1da177e4 | 1043 | { |
b2a4df20 DH |
1044 | struct assoc_array_edit *edit; |
1045 | int ret; | |
1da177e4 | 1046 | |
16feef43 | 1047 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1048 | keyring->serial, index_key->type->name, index_key->description); |
1049 | ||
1050 | BUG_ON(index_key->desc_len == 0); | |
1da177e4 | 1051 | |
1da177e4 | 1052 | if (keyring->type != &key_type_keyring) |
f70e2e06 DH |
1053 | return -ENOTDIR; |
1054 | ||
1055 | down_write(&keyring->sem); | |
1056 | ||
1057 | ret = -EKEYREVOKED; | |
1058 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
1059 | goto error_krsem; | |
1da177e4 | 1060 | |
f70e2e06 DH |
1061 | /* serialise link/link calls to prevent parallel calls causing a cycle |
1062 | * when linking two keyring in opposite orders */ | |
16feef43 | 1063 | if (index_key->type == &key_type_keyring) |
553d603c DH |
1064 | down_write(&keyring_serialise_link_sem); |
1065 | ||
b2a4df20 DH |
1066 | /* Create an edit script that will insert/replace the key in the |
1067 | * keyring tree. | |
1068 | */ | |
1069 | edit = assoc_array_insert(&keyring->keys, | |
1070 | &keyring_assoc_array_ops, | |
1071 | index_key, | |
1072 | NULL); | |
1073 | if (IS_ERR(edit)) { | |
1074 | ret = PTR_ERR(edit); | |
034faeb9 DH |
1075 | goto error_sem; |
1076 | } | |
1077 | ||
1078 | /* If we're not replacing a link in-place then we're going to need some | |
1079 | * extra quota. | |
1080 | */ | |
1081 | if (!edit->dead_leaf) { | |
1082 | ret = key_payload_reserve(keyring, | |
1083 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1084 | if (ret < 0) | |
1085 | goto error_cancel; | |
1da177e4 LT |
1086 | } |
1087 | ||
b2a4df20 | 1088 | *_edit = edit; |
f70e2e06 DH |
1089 | kleave(" = 0"); |
1090 | return 0; | |
1da177e4 | 1091 | |
034faeb9 DH |
1092 | error_cancel: |
1093 | assoc_array_cancel_edit(edit); | |
f70e2e06 | 1094 | error_sem: |
16feef43 | 1095 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1096 | up_write(&keyring_serialise_link_sem); |
1097 | error_krsem: | |
1098 | up_write(&keyring->sem); | |
1099 | kleave(" = %d", ret); | |
1100 | return ret; | |
1101 | } | |
1da177e4 | 1102 | |
f70e2e06 | 1103 | /* |
973c9f4f DH |
1104 | * Check already instantiated keys aren't going to be a problem. |
1105 | * | |
1106 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1107 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1108 | */ |
1109 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1110 | { | |
1111 | if (key->type == &key_type_keyring) | |
1112 | /* check that we aren't going to create a cycle by linking one | |
1113 | * keyring to another */ | |
1114 | return keyring_detect_cycle(keyring, key); | |
1115 | return 0; | |
1116 | } | |
1117 | ||
1118 | /* | |
973c9f4f DH |
1119 | * Link a key into to a keyring. |
1120 | * | |
1121 | * Must be called with __key_link_begin() having being called. Discards any | |
1122 | * already extant link to matching key if there is one, so that each keyring | |
1123 | * holds at most one link to any given key of a particular type+description | |
1124 | * combination. | |
f70e2e06 | 1125 | */ |
b2a4df20 | 1126 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1127 | { |
ccc3e6d9 | 1128 | __key_get(key); |
b2a4df20 DH |
1129 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1130 | assoc_array_apply_edit(*_edit); | |
1131 | *_edit = NULL; | |
f70e2e06 DH |
1132 | } |
1133 | ||
1134 | /* | |
973c9f4f DH |
1135 | * Finish linking a key into to a keyring. |
1136 | * | |
1137 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1138 | */ |
16feef43 DH |
1139 | void __key_link_end(struct key *keyring, |
1140 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1141 | struct assoc_array_edit *edit) |
f70e2e06 | 1142 | __releases(&keyring->sem) |
423b9788 | 1143 | __releases(&keyring_serialise_link_sem) |
f70e2e06 | 1144 | { |
16feef43 | 1145 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1146 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1147 | |
16feef43 | 1148 | if (index_key->type == &key_type_keyring) |
f70e2e06 DH |
1149 | up_write(&keyring_serialise_link_sem); |
1150 | ||
034faeb9 | 1151 | if (edit && !edit->dead_leaf) { |
b2a4df20 DH |
1152 | key_payload_reserve(keyring, |
1153 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1154 | assoc_array_cancel_edit(edit); | |
f70e2e06 DH |
1155 | } |
1156 | up_write(&keyring->sem); | |
1157 | } | |
1da177e4 | 1158 | |
973c9f4f DH |
1159 | /** |
1160 | * key_link - Link a key to a keyring | |
1161 | * @keyring: The keyring to make the link in. | |
1162 | * @key: The key to link to. | |
1163 | * | |
1164 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1165 | * on that key and the key can potentially be found by searching that keyring. | |
1166 | * | |
1167 | * This function will write-lock the keyring's semaphore and will consume some | |
1168 | * of the user's key data quota to hold the link. | |
1169 | * | |
1170 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1171 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1172 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1173 | * another link or -ENOMEM if there's insufficient memory. | |
1174 | * | |
1175 | * It is assumed that the caller has checked that it is permitted for a link to | |
1176 | * be made (the keyring should have Write permission and the key Link | |
1177 | * permission). | |
1da177e4 LT |
1178 | */ |
1179 | int key_link(struct key *keyring, struct key *key) | |
1180 | { | |
b2a4df20 | 1181 | struct assoc_array_edit *edit; |
1da177e4 LT |
1182 | int ret; |
1183 | ||
b2a4df20 DH |
1184 | kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage)); |
1185 | ||
1da177e4 LT |
1186 | key_check(keyring); |
1187 | key_check(key); | |
1188 | ||
008643b8 DH |
1189 | if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) && |
1190 | !test_bit(KEY_FLAG_TRUSTED, &key->flags)) | |
1191 | return -EPERM; | |
1192 | ||
b2a4df20 | 1193 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
f70e2e06 | 1194 | if (ret == 0) { |
b2a4df20 | 1195 | kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage)); |
f70e2e06 DH |
1196 | ret = __key_link_check_live_key(keyring, key); |
1197 | if (ret == 0) | |
b2a4df20 DH |
1198 | __key_link(key, &edit); |
1199 | __key_link_end(keyring, &key->index_key, edit); | |
f70e2e06 | 1200 | } |
1da177e4 | 1201 | |
b2a4df20 | 1202 | kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage)); |
1da177e4 | 1203 | return ret; |
f70e2e06 | 1204 | } |
1da177e4 LT |
1205 | EXPORT_SYMBOL(key_link); |
1206 | ||
973c9f4f DH |
1207 | /** |
1208 | * key_unlink - Unlink the first link to a key from a keyring. | |
1209 | * @keyring: The keyring to remove the link from. | |
1210 | * @key: The key the link is to. | |
1211 | * | |
1212 | * Remove a link from a keyring to a key. | |
1213 | * | |
1214 | * This function will write-lock the keyring's semaphore. | |
1215 | * | |
1216 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1217 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1218 | * memory. | |
1219 | * | |
1220 | * It is assumed that the caller has checked that it is permitted for a link to | |
1221 | * be removed (the keyring should have Write permission; no permissions are | |
1222 | * required on the key). | |
1da177e4 LT |
1223 | */ |
1224 | int key_unlink(struct key *keyring, struct key *key) | |
1225 | { | |
b2a4df20 DH |
1226 | struct assoc_array_edit *edit; |
1227 | int ret; | |
1da177e4 LT |
1228 | |
1229 | key_check(keyring); | |
1230 | key_check(key); | |
1231 | ||
1da177e4 | 1232 | if (keyring->type != &key_type_keyring) |
b2a4df20 | 1233 | return -ENOTDIR; |
1da177e4 LT |
1234 | |
1235 | down_write(&keyring->sem); | |
1236 | ||
b2a4df20 DH |
1237 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, |
1238 | &key->index_key); | |
1239 | if (IS_ERR(edit)) { | |
1240 | ret = PTR_ERR(edit); | |
1241 | goto error; | |
1da177e4 | 1242 | } |
1da177e4 | 1243 | ret = -ENOENT; |
b2a4df20 DH |
1244 | if (edit == NULL) |
1245 | goto error; | |
1da177e4 | 1246 | |
b2a4df20 | 1247 | assoc_array_apply_edit(edit); |
034faeb9 | 1248 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); |
1da177e4 LT |
1249 | ret = 0; |
1250 | ||
76d8aeab | 1251 | error: |
76d8aeab | 1252 | up_write(&keyring->sem); |
b2a4df20 | 1253 | return ret; |
a8b17ed0 | 1254 | } |
1da177e4 LT |
1255 | EXPORT_SYMBOL(key_unlink); |
1256 | ||
973c9f4f DH |
1257 | /** |
1258 | * keyring_clear - Clear a keyring | |
1259 | * @keyring: The keyring to clear. | |
1260 | * | |
1261 | * Clear the contents of the specified keyring. | |
1262 | * | |
1263 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1264 | */ |
1265 | int keyring_clear(struct key *keyring) | |
1266 | { | |
b2a4df20 | 1267 | struct assoc_array_edit *edit; |
76d8aeab | 1268 | int ret; |
1da177e4 | 1269 | |
b2a4df20 DH |
1270 | if (keyring->type != &key_type_keyring) |
1271 | return -ENOTDIR; | |
1da177e4 | 1272 | |
b2a4df20 | 1273 | down_write(&keyring->sem); |
1da177e4 | 1274 | |
b2a4df20 DH |
1275 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1276 | if (IS_ERR(edit)) { | |
1277 | ret = PTR_ERR(edit); | |
1278 | } else { | |
1279 | if (edit) | |
1280 | assoc_array_apply_edit(edit); | |
1281 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1282 | ret = 0; |
1283 | } | |
1284 | ||
b2a4df20 | 1285 | up_write(&keyring->sem); |
1da177e4 | 1286 | return ret; |
a8b17ed0 | 1287 | } |
1da177e4 | 1288 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1289 | |
31204ed9 | 1290 | /* |
973c9f4f DH |
1291 | * Dispose of the links from a revoked keyring. |
1292 | * | |
1293 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1294 | */ |
1295 | static void keyring_revoke(struct key *keyring) | |
1296 | { | |
b2a4df20 | 1297 | struct assoc_array_edit *edit; |
f0641cba | 1298 | |
b2a4df20 DH |
1299 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1300 | if (!IS_ERR(edit)) { | |
1301 | if (edit) | |
1302 | assoc_array_apply_edit(edit); | |
1303 | key_payload_reserve(keyring, 0); | |
1304 | } | |
1305 | } | |
31204ed9 | 1306 | |
b2a4df20 DH |
1307 | static bool gc_iterator(void *object, void *iterator_data) |
1308 | { | |
1309 | struct key *key = keyring_ptr_to_key(object); | |
1310 | time_t *limit = iterator_data; | |
31204ed9 | 1311 | |
b2a4df20 DH |
1312 | if (key_is_dead(key, *limit)) |
1313 | return false; | |
1314 | key_get(key); | |
1315 | return true; | |
a8b17ed0 | 1316 | } |
5d135440 | 1317 | |
5d135440 | 1318 | /* |
973c9f4f DH |
1319 | * Collect garbage from the contents of a keyring, replacing the old list with |
1320 | * a new one with the pointers all shuffled down. | |
1321 | * | |
1322 | * Dead keys are classed as oned that are flagged as being dead or are revoked, | |
1323 | * expired or negative keys that were revoked or expired before the specified | |
1324 | * limit. | |
5d135440 DH |
1325 | */ |
1326 | void keyring_gc(struct key *keyring, time_t limit) | |
1327 | { | |
c08ef808 | 1328 | kenter("{%x,%s}", key_serial(keyring), keyring->description); |
5d135440 DH |
1329 | |
1330 | down_write(&keyring->sem); | |
b2a4df20 DH |
1331 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
1332 | gc_iterator, &limit); | |
c08ef808 | 1333 | up_write(&keyring->sem); |
c08ef808 | 1334 | |
b2a4df20 | 1335 | kleave(""); |
5d135440 | 1336 | } |