Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
69664cf1 | 2 | /* Keyring handling |
1da177e4 | 3 | * |
b2a4df20 | 4 | * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved. |
1da177e4 | 5 | * Written by David Howells (dhowells@redhat.com) |
1da177e4 LT |
6 | */ |
7 | ||
876979c9 | 8 | #include <linux/export.h> |
1da177e4 LT |
9 | #include <linux/init.h> |
10 | #include <linux/sched.h> | |
11 | #include <linux/slab.h> | |
29db9190 | 12 | #include <linux/security.h> |
1da177e4 LT |
13 | #include <linux/seq_file.h> |
14 | #include <linux/err.h> | |
b206f281 | 15 | #include <linux/user_namespace.h> |
9b242610 | 16 | #include <linux/nsproxy.h> |
e9e349b0 | 17 | #include <keys/keyring-type.h> |
b2a4df20 DH |
18 | #include <keys/user-type.h> |
19 | #include <linux/assoc_array_priv.h> | |
512ea3bc | 20 | #include <linux/uaccess.h> |
9b242610 | 21 | #include <net/net_namespace.h> |
1da177e4 LT |
22 | #include "internal.h" |
23 | ||
24 | /* | |
973c9f4f DH |
25 | * When plumbing the depths of the key tree, this sets a hard limit |
26 | * set on how deep we're willing to go. | |
1da177e4 LT |
27 | */ |
28 | #define KEYRING_SEARCH_MAX_DEPTH 6 | |
29 | ||
b2a4df20 DH |
30 | /* |
31 | * We mark pointers we pass to the associative array with bit 1 set if | |
32 | * they're keyrings and clear otherwise. | |
33 | */ | |
34 | #define KEYRING_PTR_SUBTYPE 0x2UL | |
35 | ||
36 | static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x) | |
37 | { | |
38 | return (unsigned long)x & KEYRING_PTR_SUBTYPE; | |
39 | } | |
40 | static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x) | |
41 | { | |
42 | void *object = assoc_array_ptr_to_leaf(x); | |
43 | return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE); | |
44 | } | |
45 | static inline void *keyring_key_to_ptr(struct key *key) | |
46 | { | |
47 | if (key->type == &key_type_keyring) | |
48 | return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE); | |
49 | return key; | |
50 | } | |
51 | ||
1da177e4 LT |
52 | static DEFINE_RWLOCK(keyring_name_lock); |
53 | ||
b206f281 DH |
54 | /* |
55 | * Clean up the bits of user_namespace that belong to us. | |
56 | */ | |
57 | void key_free_user_ns(struct user_namespace *ns) | |
1da177e4 | 58 | { |
b206f281 DH |
59 | write_lock(&keyring_name_lock); |
60 | list_del_init(&ns->keyring_name_list); | |
61 | write_unlock(&keyring_name_lock); | |
1da177e4 | 62 | |
0f44e4d9 | 63 | key_put(ns->user_keyring_register); |
b206f281 DH |
64 | #ifdef CONFIG_PERSISTENT_KEYRINGS |
65 | key_put(ns->persistent_keyring_register); | |
66 | #endif | |
1da177e4 LT |
67 | } |
68 | ||
69 | /* | |
973c9f4f DH |
70 | * The keyring key type definition. Keyrings are simply keys of this type and |
71 | * can be treated as ordinary keys in addition to having their own special | |
72 | * operations. | |
1da177e4 | 73 | */ |
5d19e20b DH |
74 | static int keyring_preparse(struct key_preparsed_payload *prep); |
75 | static void keyring_free_preparse(struct key_preparsed_payload *prep); | |
1da177e4 | 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, |
5d19e20b DH |
87 | .preparse = keyring_preparse, |
88 | .free_preparse = keyring_free_preparse, | |
1da177e4 | 89 | .instantiate = keyring_instantiate, |
31204ed9 | 90 | .revoke = keyring_revoke, |
1da177e4 LT |
91 | .destroy = keyring_destroy, |
92 | .describe = keyring_describe, | |
93 | .read = keyring_read, | |
94 | }; | |
7318226e DH |
95 | EXPORT_SYMBOL(key_type_keyring); |
96 | ||
1da177e4 | 97 | /* |
973c9f4f DH |
98 | * Semaphore to serialise link/link calls to prevent two link calls in parallel |
99 | * introducing a cycle. | |
1da177e4 | 100 | */ |
3be59f74 | 101 | static DEFINE_MUTEX(keyring_serialise_link_lock); |
1da177e4 | 102 | |
1da177e4 | 103 | /* |
973c9f4f | 104 | * Publish the name of a keyring so that it can be found by name (if it has |
b206f281 | 105 | * one and it doesn't begin with a dot). |
1da177e4 | 106 | */ |
69664cf1 | 107 | static void keyring_publish_name(struct key *keyring) |
1da177e4 | 108 | { |
b206f281 | 109 | struct user_namespace *ns = current_user_ns(); |
1da177e4 | 110 | |
b206f281 DH |
111 | if (keyring->description && |
112 | keyring->description[0] && | |
113 | keyring->description[0] != '.') { | |
1da177e4 | 114 | write_lock(&keyring_name_lock); |
b206f281 | 115 | list_add_tail(&keyring->name_link, &ns->keyring_name_list); |
1da177e4 LT |
116 | write_unlock(&keyring_name_lock); |
117 | } | |
a8b17ed0 | 118 | } |
1da177e4 | 119 | |
5d19e20b DH |
120 | /* |
121 | * Preparse a keyring payload | |
122 | */ | |
123 | static int keyring_preparse(struct key_preparsed_payload *prep) | |
124 | { | |
125 | return prep->datalen != 0 ? -EINVAL : 0; | |
126 | } | |
127 | ||
128 | /* | |
129 | * Free a preparse of a user defined key payload | |
130 | */ | |
131 | static void keyring_free_preparse(struct key_preparsed_payload *prep) | |
132 | { | |
133 | } | |
134 | ||
1da177e4 | 135 | /* |
973c9f4f DH |
136 | * Initialise a keyring. |
137 | * | |
138 | * Returns 0 on success, -EINVAL if given any data. | |
1da177e4 LT |
139 | */ |
140 | static int keyring_instantiate(struct key *keyring, | |
cf7f601c | 141 | struct key_preparsed_payload *prep) |
1da177e4 | 142 | { |
5d19e20b DH |
143 | assoc_array_init(&keyring->keys); |
144 | /* make the keyring available by name if it has one */ | |
145 | keyring_publish_name(keyring); | |
146 | return 0; | |
a8b17ed0 | 147 | } |
1da177e4 | 148 | |
1da177e4 | 149 | /* |
b2a4df20 DH |
150 | * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd |
151 | * fold the carry back too, but that requires inline asm. | |
152 | */ | |
153 | static u64 mult_64x32_and_fold(u64 x, u32 y) | |
154 | { | |
155 | u64 hi = (u64)(u32)(x >> 32) * y; | |
156 | u64 lo = (u64)(u32)(x) * y; | |
157 | return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32); | |
158 | } | |
159 | ||
160 | /* | |
161 | * Hash a key type and description. | |
162 | */ | |
355ef8e1 | 163 | static void hash_key_type_and_desc(struct keyring_index_key *index_key) |
b2a4df20 DH |
164 | { |
165 | const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP; | |
d54e58b7 | 166 | const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK; |
b2a4df20 DH |
167 | const char *description = index_key->description; |
168 | unsigned long hash, type; | |
169 | u32 piece; | |
170 | u64 acc; | |
171 | int n, desc_len = index_key->desc_len; | |
172 | ||
173 | type = (unsigned long)index_key->type; | |
b2a4df20 DH |
174 | acc = mult_64x32_and_fold(type, desc_len + 13); |
175 | acc = mult_64x32_and_fold(acc, 9207); | |
3b6e4de0 DH |
176 | piece = (unsigned long)index_key->domain_tag; |
177 | acc = mult_64x32_and_fold(acc, piece); | |
178 | acc = mult_64x32_and_fold(acc, 9207); | |
f771fde8 | 179 | |
b2a4df20 DH |
180 | for (;;) { |
181 | n = desc_len; | |
182 | if (n <= 0) | |
183 | break; | |
184 | if (n > 4) | |
185 | n = 4; | |
186 | piece = 0; | |
187 | memcpy(&piece, description, n); | |
188 | description += n; | |
189 | desc_len -= n; | |
190 | acc = mult_64x32_and_fold(acc, piece); | |
191 | acc = mult_64x32_and_fold(acc, 9207); | |
192 | } | |
193 | ||
194 | /* Fold the hash down to 32 bits if need be. */ | |
195 | hash = acc; | |
196 | if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32) | |
197 | hash ^= acc >> 32; | |
198 | ||
199 | /* Squidge all the keyrings into a separate part of the tree to | |
200 | * ordinary keys by making sure the lowest level segment in the hash is | |
201 | * zero for keyrings and non-zero otherwise. | |
202 | */ | |
d54e58b7 | 203 | if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0) |
355ef8e1 DH |
204 | hash |= (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1; |
205 | else if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0) | |
206 | hash = (hash + (hash << level_shift)) & ~fan_mask; | |
207 | index_key->hash = hash; | |
b2a4df20 DH |
208 | } |
209 | ||
210 | /* | |
355ef8e1 | 211 | * Finalise an index key to include a part of the description actually in the |
3b6e4de0 | 212 | * index key, to set the domain tag and to calculate the hash. |
355ef8e1 DH |
213 | */ |
214 | void key_set_index_key(struct keyring_index_key *index_key) | |
215 | { | |
3b6e4de0 | 216 | static struct key_tag default_domain_tag = { .usage = REFCOUNT_INIT(1), }; |
355ef8e1 | 217 | size_t n = min_t(size_t, index_key->desc_len, sizeof(index_key->desc)); |
3b6e4de0 | 218 | |
355ef8e1 DH |
219 | memcpy(index_key->desc, index_key->description, n); |
220 | ||
a58946c1 DH |
221 | if (!index_key->domain_tag) { |
222 | if (index_key->type->flags & KEY_TYPE_NET_DOMAIN) | |
223 | index_key->domain_tag = current->nsproxy->net_ns->key_domain; | |
224 | else | |
225 | index_key->domain_tag = &default_domain_tag; | |
226 | } | |
227 | ||
355ef8e1 | 228 | hash_key_type_and_desc(index_key); |
b2a4df20 DH |
229 | } |
230 | ||
3b6e4de0 DH |
231 | /** |
232 | * key_put_tag - Release a ref on a tag. | |
233 | * @tag: The tag to release. | |
b2a4df20 | 234 | * |
3b6e4de0 DH |
235 | * This releases a reference the given tag and returns true if that ref was the |
236 | * last one. | |
237 | */ | |
238 | bool key_put_tag(struct key_tag *tag) | |
239 | { | |
240 | if (refcount_dec_and_test(&tag->usage)) { | |
241 | kfree_rcu(tag, rcu); | |
242 | return true; | |
243 | } | |
244 | ||
245 | return false; | |
246 | } | |
247 | ||
218e6424 DH |
248 | /** |
249 | * key_remove_domain - Kill off a key domain and gc its keys | |
250 | * @domain_tag: The domain tag to release. | |
b2a4df20 | 251 | * |
218e6424 DH |
252 | * This marks a domain tag as being dead and releases a ref on it. If that |
253 | * wasn't the last reference, the garbage collector is poked to try and delete | |
254 | * all keys that were in the domain. | |
255 | */ | |
256 | void key_remove_domain(struct key_tag *domain_tag) | |
257 | { | |
258 | domain_tag->removed = true; | |
259 | if (!key_put_tag(domain_tag)) | |
260 | key_schedule_gc_links(); | |
261 | } | |
262 | ||
b2a4df20 DH |
263 | /* |
264 | * Build the next index key chunk. | |
b2a4df20 DH |
265 | * |
266 | * We return it one word-sized chunk at a time. | |
1da177e4 | 267 | */ |
b2a4df20 DH |
268 | static unsigned long keyring_get_key_chunk(const void *data, int level) |
269 | { | |
270 | const struct keyring_index_key *index_key = data; | |
271 | unsigned long chunk = 0; | |
f771fde8 | 272 | const u8 *d; |
b2a4df20 DH |
273 | int desc_len = index_key->desc_len, n = sizeof(chunk); |
274 | ||
275 | level /= ASSOC_ARRAY_KEY_CHUNK_SIZE; | |
276 | switch (level) { | |
277 | case 0: | |
355ef8e1 | 278 | return index_key->hash; |
b2a4df20 | 279 | case 1: |
f771fde8 | 280 | return index_key->x; |
b2a4df20 | 281 | case 2: |
f771fde8 | 282 | return (unsigned long)index_key->type; |
3b6e4de0 DH |
283 | case 3: |
284 | return (unsigned long)index_key->domain_tag; | |
b2a4df20 | 285 | default: |
3b6e4de0 | 286 | level -= 4; |
f771fde8 | 287 | if (desc_len <= sizeof(index_key->desc)) |
b2a4df20 | 288 | return 0; |
f771fde8 DH |
289 | |
290 | d = index_key->description + sizeof(index_key->desc); | |
291 | d += level * sizeof(long); | |
292 | desc_len -= sizeof(index_key->desc); | |
b2a4df20 DH |
293 | if (desc_len > n) |
294 | desc_len = n; | |
b2a4df20 DH |
295 | do { |
296 | chunk <<= 8; | |
f771fde8 | 297 | chunk |= *d++; |
b2a4df20 | 298 | } while (--desc_len > 0); |
b2a4df20 DH |
299 | return chunk; |
300 | } | |
301 | } | |
302 | ||
303 | static unsigned long keyring_get_object_key_chunk(const void *object, int level) | |
304 | { | |
305 | const struct key *key = keyring_ptr_to_key(object); | |
306 | return keyring_get_key_chunk(&key->index_key, level); | |
307 | } | |
308 | ||
309 | static bool keyring_compare_object(const void *object, const void *data) | |
1da177e4 | 310 | { |
b2a4df20 DH |
311 | const struct keyring_index_key *index_key = data; |
312 | const struct key *key = keyring_ptr_to_key(object); | |
313 | ||
314 | return key->index_key.type == index_key->type && | |
3b6e4de0 | 315 | key->index_key.domain_tag == index_key->domain_tag && |
b2a4df20 DH |
316 | key->index_key.desc_len == index_key->desc_len && |
317 | memcmp(key->index_key.description, index_key->description, | |
318 | index_key->desc_len) == 0; | |
a8b17ed0 | 319 | } |
1da177e4 | 320 | |
b2a4df20 DH |
321 | /* |
322 | * Compare the index keys of a pair of objects and determine the bit position | |
323 | * at which they differ - if they differ. | |
324 | */ | |
23fd78d7 | 325 | static int keyring_diff_objects(const void *object, const void *data) |
b2a4df20 | 326 | { |
23fd78d7 | 327 | const struct key *key_a = keyring_ptr_to_key(object); |
b2a4df20 | 328 | const struct keyring_index_key *a = &key_a->index_key; |
23fd78d7 | 329 | const struct keyring_index_key *b = data; |
b2a4df20 DH |
330 | unsigned long seg_a, seg_b; |
331 | int level, i; | |
332 | ||
333 | level = 0; | |
355ef8e1 DH |
334 | seg_a = a->hash; |
335 | seg_b = b->hash; | |
b2a4df20 DH |
336 | if ((seg_a ^ seg_b) != 0) |
337 | goto differ; | |
f771fde8 | 338 | level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8; |
b2a4df20 DH |
339 | |
340 | /* The number of bits contributed by the hash is controlled by a | |
341 | * constant in the assoc_array headers. Everything else thereafter we | |
342 | * can deal with as being machine word-size dependent. | |
343 | */ | |
f771fde8 DH |
344 | seg_a = a->x; |
345 | seg_b = b->x; | |
b2a4df20 DH |
346 | if ((seg_a ^ seg_b) != 0) |
347 | goto differ; | |
f771fde8 | 348 | level += sizeof(unsigned long); |
b2a4df20 DH |
349 | |
350 | /* The next bit may not work on big endian */ | |
b2a4df20 DH |
351 | seg_a = (unsigned long)a->type; |
352 | seg_b = (unsigned long)b->type; | |
353 | if ((seg_a ^ seg_b) != 0) | |
354 | goto differ; | |
b2a4df20 | 355 | level += sizeof(unsigned long); |
b2a4df20 | 356 | |
3b6e4de0 DH |
357 | seg_a = (unsigned long)a->domain_tag; |
358 | seg_b = (unsigned long)b->domain_tag; | |
359 | if ((seg_a ^ seg_b) != 0) | |
360 | goto differ; | |
b2a4df20 | 361 | level += sizeof(unsigned long); |
b2a4df20 | 362 | |
f771fde8 DH |
363 | i = sizeof(a->desc); |
364 | if (a->desc_len <= i) | |
365 | goto same; | |
b2a4df20 DH |
366 | |
367 | for (; i < a->desc_len; i++) { | |
368 | seg_a = *(unsigned char *)(a->description + i); | |
369 | seg_b = *(unsigned char *)(b->description + i); | |
370 | if ((seg_a ^ seg_b) != 0) | |
371 | goto differ_plus_i; | |
372 | } | |
373 | ||
374 | same: | |
375 | return -1; | |
376 | ||
377 | differ_plus_i: | |
378 | level += i; | |
379 | differ: | |
380 | i = level * 8 + __ffs(seg_a ^ seg_b); | |
381 | return i; | |
382 | } | |
383 | ||
384 | /* | |
385 | * Free an object after stripping the keyring flag off of the pointer. | |
386 | */ | |
387 | static void keyring_free_object(void *object) | |
388 | { | |
389 | key_put(keyring_ptr_to_key(object)); | |
390 | } | |
391 | ||
392 | /* | |
393 | * Operations for keyring management by the index-tree routines. | |
394 | */ | |
395 | static const struct assoc_array_ops keyring_assoc_array_ops = { | |
396 | .get_key_chunk = keyring_get_key_chunk, | |
397 | .get_object_key_chunk = keyring_get_object_key_chunk, | |
398 | .compare_object = keyring_compare_object, | |
399 | .diff_objects = keyring_diff_objects, | |
400 | .free_object = keyring_free_object, | |
401 | }; | |
402 | ||
1da177e4 | 403 | /* |
973c9f4f DH |
404 | * Clean up a keyring when it is destroyed. Unpublish its name if it had one |
405 | * and dispose of its data. | |
233e4735 DH |
406 | * |
407 | * The garbage collector detects the final key_put(), removes the keyring from | |
408 | * the serial number tree and then does RCU synchronisation before coming here, | |
409 | * so we shouldn't need to worry about code poking around here with the RCU | |
410 | * readlock held by this time. | |
1da177e4 LT |
411 | */ |
412 | static void keyring_destroy(struct key *keyring) | |
413 | { | |
1da177e4 LT |
414 | if (keyring->description) { |
415 | write_lock(&keyring_name_lock); | |
94efe72f | 416 | |
146aa8b1 DH |
417 | if (keyring->name_link.next != NULL && |
418 | !list_empty(&keyring->name_link)) | |
419 | list_del(&keyring->name_link); | |
94efe72f | 420 | |
1da177e4 LT |
421 | write_unlock(&keyring_name_lock); |
422 | } | |
423 | ||
2b6aa412 MM |
424 | if (keyring->restrict_link) { |
425 | struct key_restriction *keyres = keyring->restrict_link; | |
426 | ||
427 | key_put(keyres->key); | |
428 | kfree(keyres); | |
429 | } | |
430 | ||
b2a4df20 | 431 | assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); |
a8b17ed0 | 432 | } |
1da177e4 | 433 | |
1da177e4 | 434 | /* |
973c9f4f | 435 | * Describe a keyring for /proc. |
1da177e4 LT |
436 | */ |
437 | static void keyring_describe(const struct key *keyring, struct seq_file *m) | |
438 | { | |
c8563473 | 439 | if (keyring->description) |
1da177e4 | 440 | seq_puts(m, keyring->description); |
c8563473 | 441 | else |
1da177e4 | 442 | seq_puts(m, "[anon]"); |
1da177e4 | 443 | |
363b02da | 444 | if (key_is_positive(keyring)) { |
b2a4df20 DH |
445 | if (keyring->keys.nr_leaves_on_tree != 0) |
446 | seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree); | |
78b7280c DH |
447 | else |
448 | seq_puts(m, ": empty"); | |
78b7280c | 449 | } |
a8b17ed0 | 450 | } |
1da177e4 | 451 | |
b2a4df20 | 452 | struct keyring_read_iterator_context { |
e645016a | 453 | size_t buflen; |
b2a4df20 DH |
454 | size_t count; |
455 | key_serial_t __user *buffer; | |
456 | }; | |
457 | ||
458 | static int keyring_read_iterator(const void *object, void *data) | |
459 | { | |
460 | struct keyring_read_iterator_context *ctx = data; | |
461 | const struct key *key = keyring_ptr_to_key(object); | |
462 | int ret; | |
463 | ||
464 | kenter("{%s,%d},,{%zu/%zu}", | |
e645016a | 465 | key->type->name, key->serial, ctx->count, ctx->buflen); |
b2a4df20 | 466 | |
e645016a | 467 | if (ctx->count >= ctx->buflen) |
b2a4df20 DH |
468 | return 1; |
469 | ||
470 | ret = put_user(key->serial, ctx->buffer); | |
471 | if (ret < 0) | |
472 | return ret; | |
473 | ctx->buffer++; | |
474 | ctx->count += sizeof(key->serial); | |
475 | return 0; | |
476 | } | |
477 | ||
1da177e4 | 478 | /* |
973c9f4f DH |
479 | * Read a list of key IDs from the keyring's contents in binary form |
480 | * | |
b2a4df20 DH |
481 | * The keyring's semaphore is read-locked by the caller. This prevents someone |
482 | * from modifying it under us - which could cause us to read key IDs multiple | |
483 | * times. | |
1da177e4 LT |
484 | */ |
485 | static long keyring_read(const struct key *keyring, | |
486 | char __user *buffer, size_t buflen) | |
487 | { | |
b2a4df20 | 488 | struct keyring_read_iterator_context ctx; |
3239b6f2 | 489 | long ret; |
1da177e4 | 490 | |
b2a4df20 DH |
491 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
492 | ||
493 | if (buflen & (sizeof(key_serial_t) - 1)) | |
494 | return -EINVAL; | |
495 | ||
3239b6f2 EB |
496 | /* Copy as many key IDs as fit into the buffer */ |
497 | if (buffer && buflen) { | |
498 | ctx.buffer = (key_serial_t __user *)buffer; | |
499 | ctx.buflen = buflen; | |
500 | ctx.count = 0; | |
501 | ret = assoc_array_iterate(&keyring->keys, | |
502 | keyring_read_iterator, &ctx); | |
503 | if (ret < 0) { | |
504 | kleave(" = %ld [iterate]", ret); | |
505 | return ret; | |
506 | } | |
1da177e4 LT |
507 | } |
508 | ||
3239b6f2 EB |
509 | /* Return the size of the buffer needed */ |
510 | ret = keyring->keys.nr_leaves_on_tree * sizeof(key_serial_t); | |
511 | if (ret <= buflen) | |
512 | kleave("= %ld [ok]", ret); | |
513 | else | |
514 | kleave("= %ld [buffer too small]", ret); | |
515 | return ret; | |
a8b17ed0 | 516 | } |
1da177e4 | 517 | |
028db3e2 LT |
518 | /* |
519 | * Allocate a keyring and link into the destination keyring. | |
1da177e4 | 520 | */ |
9a56c2db | 521 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
028db3e2 | 522 | const struct cred *cred, key_perm_t perm, |
5ac7eace | 523 | unsigned long flags, |
2b6aa412 | 524 | struct key_restriction *restrict_link, |
5ac7eace | 525 | struct key *dest) |
1da177e4 LT |
526 | { |
527 | struct key *keyring; | |
528 | int ret; | |
529 | ||
530 | keyring = key_alloc(&key_type_keyring, description, | |
028db3e2 | 531 | uid, gid, cred, perm, flags, restrict_link); |
1da177e4 | 532 | if (!IS_ERR(keyring)) { |
3e30148c | 533 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
534 | if (ret < 0) { |
535 | key_put(keyring); | |
536 | keyring = ERR_PTR(ret); | |
537 | } | |
538 | } | |
539 | ||
540 | return keyring; | |
a8b17ed0 | 541 | } |
f8aa23a5 | 542 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 543 | |
5ac7eace DH |
544 | /** |
545 | * restrict_link_reject - Give -EPERM to restrict link | |
546 | * @keyring: The keyring being added to. | |
547 | * @type: The type of key being added. | |
5ac7eace | 548 | * @payload: The payload of the key intended to be added. |
9fd16537 | 549 | * @restriction_key: Keys providing additional data for evaluating restriction. |
5ac7eace DH |
550 | * |
551 | * Reject the addition of any links to a keyring. It can be overridden by | |
552 | * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when | |
553 | * adding a key to a keyring. | |
554 | * | |
2b6aa412 MM |
555 | * This is meant to be stored in a key_restriction structure which is passed |
556 | * in the restrict_link parameter to keyring_alloc(). | |
5ac7eace DH |
557 | */ |
558 | int restrict_link_reject(struct key *keyring, | |
559 | const struct key_type *type, | |
aaf66c88 MM |
560 | const union key_payload *payload, |
561 | struct key *restriction_key) | |
5ac7eace DH |
562 | { |
563 | return -EPERM; | |
564 | } | |
565 | ||
c06cfb08 DH |
566 | /* |
567 | * By default, we keys found by getting an exact match on their descriptions. | |
568 | */ | |
0c903ab6 DH |
569 | bool key_default_cmp(const struct key *key, |
570 | const struct key_match_data *match_data) | |
c06cfb08 DH |
571 | { |
572 | return strcmp(key->description, match_data->raw_data) == 0; | |
573 | } | |
574 | ||
b2a4df20 DH |
575 | /* |
576 | * Iteration function to consider each key found. | |
1da177e4 | 577 | */ |
b2a4df20 | 578 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 579 | { |
b2a4df20 DH |
580 | struct keyring_search_context *ctx = iterator_data; |
581 | const struct key *key = keyring_ptr_to_key(object); | |
363b02da DH |
582 | unsigned long kflags = READ_ONCE(key->flags); |
583 | short state = READ_ONCE(key->state); | |
1da177e4 | 584 | |
b2a4df20 | 585 | kenter("{%d}", key->serial); |
1da177e4 | 586 | |
b2a4df20 DH |
587 | /* ignore keys not of this type */ |
588 | if (key->type != ctx->index_key.type) { | |
589 | kleave(" = 0 [!type]"); | |
590 | return 0; | |
29db9190 | 591 | } |
1da177e4 | 592 | |
b2a4df20 DH |
593 | /* skip invalidated, revoked and expired keys */ |
594 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
074d5898 | 595 | time64_t expiry = READ_ONCE(key->expiry); |
9d6c8711 | 596 | |
b2a4df20 DH |
597 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | |
598 | (1 << KEY_FLAG_REVOKED))) { | |
599 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
600 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
601 | goto skipped; | |
602 | } | |
1da177e4 | 603 | |
074d5898 | 604 | if (expiry && ctx->now >= expiry) { |
0b0a8415 DH |
605 | if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) |
606 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
b2a4df20 DH |
607 | kleave(" = %d [expire]", ctx->skipped_ret); |
608 | goto skipped; | |
609 | } | |
610 | } | |
664cceb0 | 611 | |
b2a4df20 | 612 | /* keys that don't match */ |
46291959 | 613 | if (!ctx->match_data.cmp(key, &ctx->match_data)) { |
b2a4df20 DH |
614 | kleave(" = 0 [!match]"); |
615 | return 0; | |
616 | } | |
dceba994 | 617 | |
b2a4df20 DH |
618 | /* key must have search permissions */ |
619 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
620 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 621 | ctx->cred, KEY_NEED_SEARCH) < 0) { |
b2a4df20 DH |
622 | ctx->result = ERR_PTR(-EACCES); |
623 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
624 | goto skipped; | |
dceba994 KC |
625 | } |
626 | ||
b2a4df20 DH |
627 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
628 | /* we set a different error code if we pass a negative key */ | |
363b02da DH |
629 | if (state < 0) { |
630 | ctx->result = ERR_PTR(state); | |
b2a4df20 DH |
631 | kleave(" = %d [neg]", ctx->skipped_ret); |
632 | goto skipped; | |
633 | } | |
634 | } | |
1da177e4 | 635 | |
b2a4df20 DH |
636 | /* Found */ |
637 | ctx->result = make_key_ref(key, ctx->possessed); | |
638 | kleave(" = 1 [found]"); | |
639 | return 1; | |
1da177e4 | 640 | |
b2a4df20 DH |
641 | skipped: |
642 | return ctx->skipped_ret; | |
643 | } | |
1da177e4 | 644 | |
b2a4df20 DH |
645 | /* |
646 | * Search inside a keyring for a key. We can search by walking to it | |
647 | * directly based on its index-key or we can iterate over the entire | |
648 | * tree looking for it, based on the match function. | |
649 | */ | |
650 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
651 | { | |
46291959 | 652 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { |
b2a4df20 DH |
653 | const void *object; |
654 | ||
655 | object = assoc_array_find(&keyring->keys, | |
656 | &keyring_assoc_array_ops, | |
657 | &ctx->index_key); | |
658 | return object ? ctx->iterator(object, ctx) : 0; | |
659 | } | |
660 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
661 | } | |
1da177e4 | 662 | |
b2a4df20 DH |
663 | /* |
664 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
665 | * depth. | |
666 | */ | |
667 | static bool search_nested_keyrings(struct key *keyring, | |
668 | struct keyring_search_context *ctx) | |
669 | { | |
670 | struct { | |
671 | struct key *keyring; | |
672 | struct assoc_array_node *node; | |
673 | int slot; | |
674 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 675 | |
b2a4df20 DH |
676 | struct assoc_array_shortcut *shortcut; |
677 | struct assoc_array_node *node; | |
678 | struct assoc_array_ptr *ptr; | |
679 | struct key *key; | |
680 | int sp = 0, slot; | |
1da177e4 | 681 | |
b2a4df20 DH |
682 | kenter("{%d},{%s,%s}", |
683 | keyring->serial, | |
684 | ctx->index_key.type->name, | |
685 | ctx->index_key.description); | |
1da177e4 | 686 | |
054f6180 DH |
687 | #define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK) |
688 | BUG_ON((ctx->flags & STATE_CHECKS) == 0 || | |
689 | (ctx->flags & STATE_CHECKS) == STATE_CHECKS); | |
690 | ||
f771fde8 DH |
691 | if (ctx->index_key.description) |
692 | key_set_index_key(&ctx->index_key); | |
693 | ||
b2a4df20 DH |
694 | /* Check to see if this top-level keyring is what we are looking for |
695 | * and whether it is valid or not. | |
696 | */ | |
46291959 | 697 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || |
b2a4df20 DH |
698 | keyring_compare_object(keyring, &ctx->index_key)) { |
699 | ctx->skipped_ret = 2; | |
b2a4df20 DH |
700 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { |
701 | case 1: | |
78b7280c | 702 | goto found; |
b2a4df20 DH |
703 | case 2: |
704 | return false; | |
705 | default: | |
706 | break; | |
1da177e4 | 707 | } |
b2a4df20 | 708 | } |
1da177e4 | 709 | |
b2a4df20 | 710 | ctx->skipped_ret = 0; |
b2a4df20 DH |
711 | |
712 | /* Start processing a new keyring */ | |
713 | descend_to_keyring: | |
714 | kdebug("descend to %d", keyring->serial); | |
715 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
716 | (1 << KEY_FLAG_REVOKED))) | |
717 | goto not_this_keyring; | |
718 | ||
719 | /* Search through the keys in this keyring before its searching its | |
720 | * subtrees. | |
721 | */ | |
722 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 723 | goto found; |
1da177e4 | 724 | |
b2a4df20 DH |
725 | /* Then manually iterate through the keyrings nested in this one. |
726 | * | |
727 | * Start from the root node of the index tree. Because of the way the | |
728 | * hash function has been set up, keyrings cluster on the leftmost | |
729 | * branch of the root node (root slot 0) or in the root node itself. | |
730 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
731 | * slots 1-15). | |
732 | */ | |
dcf49dbc DH |
733 | if (!(ctx->flags & KEYRING_SEARCH_RECURSE)) |
734 | goto not_this_keyring; | |
735 | ||
381f20fc | 736 | ptr = READ_ONCE(keyring->keys.root); |
b2a4df20 DH |
737 | if (!ptr) |
738 | goto not_this_keyring; | |
1da177e4 | 739 | |
b2a4df20 DH |
740 | if (assoc_array_ptr_is_shortcut(ptr)) { |
741 | /* If the root is a shortcut, either the keyring only contains | |
742 | * keyring pointers (everything clusters behind root slot 0) or | |
743 | * doesn't contain any keyring pointers. | |
1da177e4 | 744 | */ |
b2a4df20 | 745 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
b2a4df20 DH |
746 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) |
747 | goto not_this_keyring; | |
748 | ||
381f20fc | 749 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 DH |
750 | node = assoc_array_ptr_to_node(ptr); |
751 | goto begin_node; | |
752 | } | |
753 | ||
754 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
755 | ptr = node->slots[0]; |
756 | if (!assoc_array_ptr_is_meta(ptr)) | |
757 | goto begin_node; | |
758 | ||
759 | descend_to_node: | |
760 | /* Descend to a more distal node in this keyring's content tree and go | |
761 | * through that. | |
762 | */ | |
763 | kdebug("descend"); | |
764 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
765 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 766 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 | 767 | BUG_ON(!assoc_array_ptr_is_node(ptr)); |
b2a4df20 | 768 | } |
9c5e45df | 769 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
770 | |
771 | begin_node: | |
772 | kdebug("begin_node"); | |
b2a4df20 DH |
773 | slot = 0; |
774 | ascend_to_node: | |
775 | /* Go through the slots in a node */ | |
776 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
381f20fc | 777 | ptr = READ_ONCE(node->slots[slot]); |
b2a4df20 DH |
778 | |
779 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
780 | goto descend_to_node; | |
781 | ||
782 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 783 | continue; |
1da177e4 | 784 | |
b2a4df20 DH |
785 | key = keyring_ptr_to_key(ptr); |
786 | ||
787 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
788 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
789 | ctx->result = ERR_PTR(-ELOOP); | |
790 | return false; | |
791 | } | |
792 | goto not_this_keyring; | |
793 | } | |
794 | ||
795 | /* Search a nested keyring */ | |
796 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
797 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 798 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 799 | continue; |
1da177e4 LT |
800 | |
801 | /* stack the current position */ | |
31d5a79d | 802 | stack[sp].keyring = keyring; |
b2a4df20 DH |
803 | stack[sp].node = node; |
804 | stack[sp].slot = slot; | |
1da177e4 LT |
805 | sp++; |
806 | ||
807 | /* begin again with the new keyring */ | |
808 | keyring = key; | |
b2a4df20 DH |
809 | goto descend_to_keyring; |
810 | } | |
811 | ||
812 | /* We've dealt with all the slots in the current node, so now we need | |
813 | * to ascend to the parent and continue processing there. | |
814 | */ | |
381f20fc | 815 | ptr = READ_ONCE(node->back_pointer); |
b2a4df20 DH |
816 | slot = node->parent_slot; |
817 | ||
818 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
819 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 820 | ptr = READ_ONCE(shortcut->back_pointer); |
b2a4df20 DH |
821 | slot = shortcut->parent_slot; |
822 | } | |
823 | if (!ptr) | |
824 | goto not_this_keyring; | |
825 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
826 | slot++; |
827 | ||
828 | /* If we've ascended to the root (zero backpointer), we must have just | |
829 | * finished processing the leftmost branch rather than the root slots - | |
830 | * so there can't be any more keyrings for us to find. | |
831 | */ | |
832 | if (node->back_pointer) { | |
833 | kdebug("ascend %d", slot); | |
834 | goto ascend_to_node; | |
1da177e4 LT |
835 | } |
836 | ||
b2a4df20 DH |
837 | /* The keyring we're looking at was disqualified or didn't contain a |
838 | * matching key. | |
839 | */ | |
664cceb0 | 840 | not_this_keyring: |
b2a4df20 DH |
841 | kdebug("not_this_keyring %d", sp); |
842 | if (sp <= 0) { | |
843 | kleave(" = false"); | |
844 | return false; | |
1da177e4 LT |
845 | } |
846 | ||
b2a4df20 DH |
847 | /* Resume the processing of a keyring higher up in the tree */ |
848 | sp--; | |
849 | keyring = stack[sp].keyring; | |
850 | node = stack[sp].node; | |
851 | slot = stack[sp].slot + 1; | |
852 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
853 | goto ascend_to_node; | |
1da177e4 | 854 | |
b2a4df20 | 855 | /* We found a viable match */ |
664cceb0 | 856 | found: |
b2a4df20 | 857 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 858 | key_check(key); |
b2a4df20 | 859 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
074d5898 BW |
860 | key->last_used_at = ctx->now; |
861 | keyring->last_used_at = ctx->now; | |
b2a4df20 | 862 | while (sp > 0) |
074d5898 | 863 | stack[--sp].keyring->last_used_at = ctx->now; |
b2a4df20 DH |
864 | } |
865 | kleave(" = true"); | |
866 | return true; | |
867 | } | |
868 | ||
869 | /** | |
e59428f7 | 870 | * keyring_search_rcu - Search a keyring tree for a matching key under RCU |
b2a4df20 DH |
871 | * @keyring_ref: A pointer to the keyring with possession indicator. |
872 | * @ctx: The keyring search context. | |
873 | * | |
874 | * Search the supplied keyring tree for a key that matches the criteria given. | |
875 | * The root keyring and any linked keyrings must grant Search permission to the | |
876 | * caller to be searchable and keys can only be found if they too grant Search | |
877 | * to the caller. The possession flag on the root keyring pointer controls use | |
878 | * of the possessor bits in permissions checking of the entire tree. In | |
879 | * addition, the LSM gets to forbid keyring searches and key matches. | |
880 | * | |
881 | * The search is performed as a breadth-then-depth search up to the prescribed | |
e59428f7 DH |
882 | * limit (KEYRING_SEARCH_MAX_DEPTH). The caller must hold the RCU read lock to |
883 | * prevent keyrings from being destroyed or rearranged whilst they are being | |
884 | * searched. | |
b2a4df20 DH |
885 | * |
886 | * Keys are matched to the type provided and are then filtered by the match | |
887 | * function, which is given the description to use in any way it sees fit. The | |
888 | * match function may use any attributes of a key that it wishes to to | |
889 | * determine the match. Normally the match function from the key type would be | |
890 | * used. | |
891 | * | |
892 | * RCU can be used to prevent the keyring key lists from disappearing without | |
893 | * the need to take lots of locks. | |
894 | * | |
895 | * Returns a pointer to the found key and increments the key usage count if | |
896 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
897 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
898 | * specified keyring wasn't a keyring. | |
899 | * | |
900 | * In the case of a successful return, the possession attribute from | |
901 | * @keyring_ref is propagated to the returned key reference. | |
902 | */ | |
e59428f7 | 903 | key_ref_t keyring_search_rcu(key_ref_t keyring_ref, |
b2a4df20 DH |
904 | struct keyring_search_context *ctx) |
905 | { | |
906 | struct key *keyring; | |
907 | long err; | |
908 | ||
909 | ctx->iterator = keyring_search_iterator; | |
910 | ctx->possessed = is_key_possessed(keyring_ref); | |
911 | ctx->result = ERR_PTR(-EAGAIN); | |
912 | ||
913 | keyring = key_ref_to_ptr(keyring_ref); | |
914 | key_check(keyring); | |
915 | ||
916 | if (keyring->type != &key_type_keyring) | |
917 | return ERR_PTR(-ENOTDIR); | |
918 | ||
919 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 920 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
921 | if (err < 0) |
922 | return ERR_PTR(err); | |
923 | } | |
924 | ||
074d5898 | 925 | ctx->now = ktime_get_real_seconds(); |
b2a4df20 DH |
926 | if (search_nested_keyrings(keyring, ctx)) |
927 | __key_get(key_ref_to_ptr(ctx->result)); | |
b2a4df20 | 928 | return ctx->result; |
a8b17ed0 | 929 | } |
1da177e4 | 930 | |
973c9f4f DH |
931 | /** |
932 | * keyring_search - Search the supplied keyring tree for a matching key | |
933 | * @keyring: The root of the keyring tree to be searched. | |
934 | * @type: The type of keyring we want to find. | |
935 | * @description: The name of the keyring we want to find. | |
dcf49dbc | 936 | * @recurse: True to search the children of @keyring also |
973c9f4f | 937 | * |
e59428f7 | 938 | * As keyring_search_rcu() above, but using the current task's credentials and |
b2a4df20 | 939 | * type's default matching function and preferred search method. |
1da177e4 | 940 | */ |
664cceb0 DH |
941 | key_ref_t keyring_search(key_ref_t keyring, |
942 | struct key_type *type, | |
dcf49dbc DH |
943 | const char *description, |
944 | bool recurse) | |
1da177e4 | 945 | { |
4bdf0bc3 DH |
946 | struct keyring_search_context ctx = { |
947 | .index_key.type = type, | |
948 | .index_key.description = description, | |
ede0fa98 | 949 | .index_key.desc_len = strlen(description), |
4bdf0bc3 | 950 | .cred = current_cred(), |
c06cfb08 | 951 | .match_data.cmp = key_default_cmp, |
46291959 DH |
952 | .match_data.raw_data = description, |
953 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
954 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 955 | }; |
46291959 DH |
956 | key_ref_t key; |
957 | int ret; | |
4bdf0bc3 | 958 | |
dcf49dbc DH |
959 | if (recurse) |
960 | ctx.flags |= KEYRING_SEARCH_RECURSE; | |
46291959 DH |
961 | if (type->match_preparse) { |
962 | ret = type->match_preparse(&ctx.match_data); | |
963 | if (ret < 0) | |
964 | return ERR_PTR(ret); | |
965 | } | |
966 | ||
e59428f7 DH |
967 | rcu_read_lock(); |
968 | key = keyring_search_rcu(keyring, &ctx); | |
969 | rcu_read_unlock(); | |
46291959 DH |
970 | |
971 | if (type->match_free) | |
972 | type->match_free(&ctx.match_data); | |
973 | return key; | |
a8b17ed0 | 974 | } |
1da177e4 LT |
975 | EXPORT_SYMBOL(keyring_search); |
976 | ||
6563c91f MM |
977 | static struct key_restriction *keyring_restriction_alloc( |
978 | key_restrict_link_func_t check) | |
979 | { | |
980 | struct key_restriction *keyres = | |
981 | kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
982 | ||
983 | if (!keyres) | |
984 | return ERR_PTR(-ENOMEM); | |
985 | ||
986 | keyres->check = check; | |
987 | ||
988 | return keyres; | |
989 | } | |
990 | ||
991 | /* | |
992 | * Semaphore to serialise restriction setup to prevent reference count | |
993 | * cycles through restriction key pointers. | |
994 | */ | |
995 | static DECLARE_RWSEM(keyring_serialise_restrict_sem); | |
996 | ||
997 | /* | |
998 | * Check for restriction cycles that would prevent keyring garbage collection. | |
999 | * keyring_serialise_restrict_sem must be held. | |
1000 | */ | |
1001 | static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, | |
1002 | struct key_restriction *keyres) | |
1003 | { | |
1004 | while (keyres && keyres->key && | |
1005 | keyres->key->type == &key_type_keyring) { | |
1006 | if (keyres->key == dest_keyring) | |
1007 | return true; | |
1008 | ||
1009 | keyres = keyres->key->restrict_link; | |
1010 | } | |
1011 | ||
1012 | return false; | |
1013 | } | |
1014 | ||
1015 | /** | |
1016 | * keyring_restrict - Look up and apply a restriction to a keyring | |
9fd16537 DH |
1017 | * @keyring_ref: The keyring to be restricted |
1018 | * @type: The key type that will provide the restriction checker. | |
6563c91f | 1019 | * @restriction: The restriction options to apply to the keyring |
9fd16537 DH |
1020 | * |
1021 | * Look up a keyring and apply a restriction to it. The restriction is managed | |
1022 | * by the specific key type, but can be configured by the options specified in | |
1023 | * the restriction string. | |
6563c91f MM |
1024 | */ |
1025 | int keyring_restrict(key_ref_t keyring_ref, const char *type, | |
1026 | const char *restriction) | |
1027 | { | |
1028 | struct key *keyring; | |
1029 | struct key_type *restrict_type = NULL; | |
1030 | struct key_restriction *restrict_link; | |
1031 | int ret = 0; | |
1032 | ||
1033 | keyring = key_ref_to_ptr(keyring_ref); | |
1034 | key_check(keyring); | |
1035 | ||
1036 | if (keyring->type != &key_type_keyring) | |
1037 | return -ENOTDIR; | |
1038 | ||
1039 | if (!type) { | |
1040 | restrict_link = keyring_restriction_alloc(restrict_link_reject); | |
1041 | } else { | |
1042 | restrict_type = key_type_lookup(type); | |
1043 | ||
1044 | if (IS_ERR(restrict_type)) | |
1045 | return PTR_ERR(restrict_type); | |
1046 | ||
1047 | if (!restrict_type->lookup_restriction) { | |
1048 | ret = -ENOENT; | |
1049 | goto error; | |
1050 | } | |
1051 | ||
1052 | restrict_link = restrict_type->lookup_restriction(restriction); | |
1053 | } | |
1054 | ||
1055 | if (IS_ERR(restrict_link)) { | |
1056 | ret = PTR_ERR(restrict_link); | |
1057 | goto error; | |
1058 | } | |
1059 | ||
1060 | down_write(&keyring->sem); | |
1061 | down_write(&keyring_serialise_restrict_sem); | |
1062 | ||
1063 | if (keyring->restrict_link) | |
1064 | ret = -EEXIST; | |
1065 | else if (keyring_detect_restriction_cycle(keyring, restrict_link)) | |
1066 | ret = -EDEADLK; | |
1067 | else | |
1068 | keyring->restrict_link = restrict_link; | |
1069 | ||
1070 | up_write(&keyring_serialise_restrict_sem); | |
1071 | up_write(&keyring->sem); | |
1072 | ||
1073 | if (ret < 0) { | |
1074 | key_put(restrict_link->key); | |
1075 | kfree(restrict_link); | |
1076 | } | |
1077 | ||
1078 | error: | |
1079 | if (restrict_type) | |
1080 | key_type_put(restrict_type); | |
1081 | ||
1082 | return ret; | |
1083 | } | |
1084 | EXPORT_SYMBOL(keyring_restrict); | |
1085 | ||
1da177e4 | 1086 | /* |
b2a4df20 | 1087 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
1088 | * |
1089 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
1090 | * permission is granted to modify the keyring as no check is made here. The |
1091 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
1092 | * |
1093 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
1094 | * successful and returns NULL if not found. Revoked and invalidated keys are |
1095 | * skipped over. | |
973c9f4f DH |
1096 | * |
1097 | * If successful, the possession indicator is propagated from the keyring ref | |
1098 | * to the returned key reference. | |
1da177e4 | 1099 | */ |
b2a4df20 DH |
1100 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
1101 | const struct keyring_index_key *index_key) | |
1da177e4 | 1102 | { |
664cceb0 | 1103 | struct key *keyring, *key; |
b2a4df20 | 1104 | const void *object; |
1da177e4 | 1105 | |
664cceb0 | 1106 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 1107 | |
b2a4df20 DH |
1108 | kenter("{%d},{%s,%s}", |
1109 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 1110 | |
b2a4df20 DH |
1111 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
1112 | index_key); | |
1da177e4 | 1113 | |
b2a4df20 DH |
1114 | if (object) |
1115 | goto found; | |
1116 | ||
1117 | kleave(" = NULL"); | |
1118 | return NULL; | |
1da177e4 | 1119 | |
c5b60b5e | 1120 | found: |
b2a4df20 DH |
1121 | key = keyring_ptr_to_key(object); |
1122 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
1123 | (1 << KEY_FLAG_REVOKED))) { | |
1124 | kleave(" = NULL [x]"); | |
1125 | return NULL; | |
1126 | } | |
ccc3e6d9 | 1127 | __key_get(key); |
b2a4df20 DH |
1128 | kleave(" = {%d}", key->serial); |
1129 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 1130 | } |
1da177e4 | 1131 | |
1da177e4 | 1132 | /* |
973c9f4f DH |
1133 | * Find a keyring with the specified name. |
1134 | * | |
028db3e2 LT |
1135 | * Only keyrings that have nonzero refcount, are not revoked, and are owned by a |
1136 | * user in the current user namespace are considered. If @uid_keyring is %true, | |
1137 | * the keyring additionally must have been allocated as a user or user session | |
1138 | * keyring; otherwise, it must grant Search permission directly to the caller. | |
973c9f4f DH |
1139 | * |
1140 | * Returns a pointer to the keyring with the keyring's refcount having being | |
1141 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 1142 | */ |
237bbd29 | 1143 | struct key *find_keyring_by_name(const char *name, bool uid_keyring) |
1da177e4 | 1144 | { |
b206f281 | 1145 | struct user_namespace *ns = current_user_ns(); |
1da177e4 | 1146 | struct key *keyring; |
1da177e4 | 1147 | |
1da177e4 | 1148 | if (!name) |
cea7daa3 | 1149 | return ERR_PTR(-EINVAL); |
1da177e4 | 1150 | |
1da177e4 LT |
1151 | read_lock(&keyring_name_lock); |
1152 | ||
b206f281 DH |
1153 | /* Search this hash bucket for a keyring with a matching name that |
1154 | * grants Search permission and that hasn't been revoked | |
1155 | */ | |
1156 | list_for_each_entry(keyring, &ns->keyring_name_list, name_link) { | |
1157 | if (!kuid_has_mapping(ns, keyring->user->uid)) | |
1158 | continue; | |
1da177e4 | 1159 | |
b206f281 DH |
1160 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1161 | continue; | |
1da177e4 | 1162 | |
b206f281 DH |
1163 | if (strcmp(keyring->description, name) != 0) |
1164 | continue; | |
1da177e4 | 1165 | |
b206f281 DH |
1166 | if (uid_keyring) { |
1167 | if (!test_bit(KEY_FLAG_UID_KEYRING, | |
1168 | &keyring->flags)) | |
1169 | continue; | |
1170 | } else { | |
1171 | if (key_permission(make_key_ref(keyring, 0), | |
028db3e2 | 1172 | KEY_NEED_SEARCH) < 0) |
cea7daa3 | 1173 | continue; |
1da177e4 | 1174 | } |
b206f281 DH |
1175 | |
1176 | /* we've got a match but we might end up racing with | |
1177 | * key_cleanup() if the keyring is currently 'dead' | |
1178 | * (ie. it has a zero usage count) */ | |
1179 | if (!refcount_inc_not_zero(&keyring->usage)) | |
1180 | continue; | |
1181 | keyring->last_used_at = ktime_get_real_seconds(); | |
1182 | goto out; | |
1da177e4 LT |
1183 | } |
1184 | ||
1da177e4 | 1185 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1186 | out: |
1187 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1188 | return keyring; |
a8b17ed0 | 1189 | } |
1da177e4 | 1190 | |
b2a4df20 DH |
1191 | static int keyring_detect_cycle_iterator(const void *object, |
1192 | void *iterator_data) | |
1193 | { | |
1194 | struct keyring_search_context *ctx = iterator_data; | |
1195 | const struct key *key = keyring_ptr_to_key(object); | |
1196 | ||
1197 | kenter("{%d}", key->serial); | |
1198 | ||
979e0d74 DH |
1199 | /* We might get a keyring with matching index-key that is nonetheless a |
1200 | * different keyring. */ | |
46291959 | 1201 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1202 | return 0; |
1203 | ||
b2a4df20 DH |
1204 | ctx->result = ERR_PTR(-EDEADLK); |
1205 | return 1; | |
1206 | } | |
1207 | ||
1da177e4 | 1208 | /* |
973c9f4f DH |
1209 | * See if a cycle will will be created by inserting acyclic tree B in acyclic |
1210 | * tree A at the topmost level (ie: as a direct child of A). | |
1211 | * | |
1212 | * Since we are adding B to A at the top level, checking for cycles should just | |
1213 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1214 | */ |
1215 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1216 | { | |
b2a4df20 | 1217 | struct keyring_search_context ctx = { |
46291959 DH |
1218 | .index_key = A->index_key, |
1219 | .match_data.raw_data = A, | |
1220 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1221 | .iterator = keyring_detect_cycle_iterator, | |
1222 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1223 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1224 | KEYRING_SEARCH_NO_CHECK_PERM | | |
dcf49dbc DH |
1225 | KEYRING_SEARCH_DETECT_TOO_DEEP | |
1226 | KEYRING_SEARCH_RECURSE), | |
b2a4df20 | 1227 | }; |
1da177e4 | 1228 | |
76d8aeab | 1229 | rcu_read_lock(); |
b2a4df20 | 1230 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1231 | rcu_read_unlock(); |
b2a4df20 | 1232 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1233 | } |
cab8eb59 | 1234 | |
df593ee2 DH |
1235 | /* |
1236 | * Lock keyring for link. | |
1237 | */ | |
1238 | int __key_link_lock(struct key *keyring, | |
1239 | const struct keyring_index_key *index_key) | |
1240 | __acquires(&keyring->sem) | |
1241 | __acquires(&keyring_serialise_link_lock) | |
1242 | { | |
1243 | if (keyring->type != &key_type_keyring) | |
1244 | return -ENOTDIR; | |
1245 | ||
1246 | down_write(&keyring->sem); | |
1247 | ||
1248 | /* Serialise link/link calls to prevent parallel calls causing a cycle | |
1249 | * when linking two keyring in opposite orders. | |
1250 | */ | |
1251 | if (index_key->type == &key_type_keyring) | |
1252 | mutex_lock(&keyring_serialise_link_lock); | |
1253 | ||
1254 | return 0; | |
1255 | } | |
1256 | ||
ed0ac5c7 DH |
1257 | /* |
1258 | * Lock keyrings for move (link/unlink combination). | |
1259 | */ | |
1260 | int __key_move_lock(struct key *l_keyring, struct key *u_keyring, | |
1261 | const struct keyring_index_key *index_key) | |
1262 | __acquires(&l_keyring->sem) | |
1263 | __acquires(&u_keyring->sem) | |
1264 | __acquires(&keyring_serialise_link_lock) | |
1265 | { | |
1266 | if (l_keyring->type != &key_type_keyring || | |
1267 | u_keyring->type != &key_type_keyring) | |
1268 | return -ENOTDIR; | |
1269 | ||
1270 | /* We have to be very careful here to take the keyring locks in the | |
1271 | * right order, lest we open ourselves to deadlocking against another | |
1272 | * move operation. | |
1273 | */ | |
1274 | if (l_keyring < u_keyring) { | |
1275 | down_write(&l_keyring->sem); | |
1276 | down_write_nested(&u_keyring->sem, 1); | |
1277 | } else { | |
1278 | down_write(&u_keyring->sem); | |
1279 | down_write_nested(&l_keyring->sem, 1); | |
1280 | } | |
1281 | ||
1282 | /* Serialise link/link calls to prevent parallel calls causing a cycle | |
1283 | * when linking two keyring in opposite orders. | |
1284 | */ | |
1285 | if (index_key->type == &key_type_keyring) | |
1286 | mutex_lock(&keyring_serialise_link_lock); | |
1287 | ||
1288 | return 0; | |
1289 | } | |
1290 | ||
1da177e4 | 1291 | /* |
973c9f4f | 1292 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1293 | */ |
b2a4df20 DH |
1294 | int __key_link_begin(struct key *keyring, |
1295 | const struct keyring_index_key *index_key, | |
1296 | struct assoc_array_edit **_edit) | |
1da177e4 | 1297 | { |
b2a4df20 DH |
1298 | struct assoc_array_edit *edit; |
1299 | int ret; | |
1da177e4 | 1300 | |
16feef43 | 1301 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1302 | keyring->serial, index_key->type->name, index_key->description); |
1303 | ||
1304 | BUG_ON(index_key->desc_len == 0); | |
df593ee2 | 1305 | BUG_ON(*_edit != NULL); |
1da177e4 | 1306 | |
df593ee2 | 1307 | *_edit = NULL; |
f70e2e06 DH |
1308 | |
1309 | ret = -EKEYREVOKED; | |
1310 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
df593ee2 | 1311 | goto error; |
553d603c | 1312 | |
b2a4df20 DH |
1313 | /* Create an edit script that will insert/replace the key in the |
1314 | * keyring tree. | |
1315 | */ | |
1316 | edit = assoc_array_insert(&keyring->keys, | |
1317 | &keyring_assoc_array_ops, | |
1318 | index_key, | |
1319 | NULL); | |
1320 | if (IS_ERR(edit)) { | |
1321 | ret = PTR_ERR(edit); | |
df593ee2 | 1322 | goto error; |
034faeb9 DH |
1323 | } |
1324 | ||
1325 | /* If we're not replacing a link in-place then we're going to need some | |
1326 | * extra quota. | |
1327 | */ | |
1328 | if (!edit->dead_leaf) { | |
1329 | ret = key_payload_reserve(keyring, | |
1330 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1331 | if (ret < 0) | |
1332 | goto error_cancel; | |
1da177e4 LT |
1333 | } |
1334 | ||
b2a4df20 | 1335 | *_edit = edit; |
f70e2e06 DH |
1336 | kleave(" = 0"); |
1337 | return 0; | |
1da177e4 | 1338 | |
034faeb9 DH |
1339 | error_cancel: |
1340 | assoc_array_cancel_edit(edit); | |
df593ee2 | 1341 | error: |
f70e2e06 DH |
1342 | kleave(" = %d", ret); |
1343 | return ret; | |
1344 | } | |
1da177e4 | 1345 | |
f70e2e06 | 1346 | /* |
973c9f4f DH |
1347 | * Check already instantiated keys aren't going to be a problem. |
1348 | * | |
1349 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1350 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1351 | */ |
1352 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1353 | { | |
1354 | if (key->type == &key_type_keyring) | |
1355 | /* check that we aren't going to create a cycle by linking one | |
1356 | * keyring to another */ | |
1357 | return keyring_detect_cycle(keyring, key); | |
1358 | return 0; | |
1359 | } | |
1360 | ||
1361 | /* | |
973c9f4f DH |
1362 | * Link a key into to a keyring. |
1363 | * | |
1364 | * Must be called with __key_link_begin() having being called. Discards any | |
1365 | * already extant link to matching key if there is one, so that each keyring | |
1366 | * holds at most one link to any given key of a particular type+description | |
1367 | * combination. | |
f70e2e06 | 1368 | */ |
b2a4df20 | 1369 | void __key_link(struct key *key, struct assoc_array_edit **_edit) |
f70e2e06 | 1370 | { |
ccc3e6d9 | 1371 | __key_get(key); |
b2a4df20 DH |
1372 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1373 | assoc_array_apply_edit(*_edit); | |
1374 | *_edit = NULL; | |
f70e2e06 DH |
1375 | } |
1376 | ||
1377 | /* | |
973c9f4f DH |
1378 | * Finish linking a key into to a keyring. |
1379 | * | |
1380 | * Must be called with __key_link_begin() having being called. | |
f70e2e06 | 1381 | */ |
16feef43 DH |
1382 | void __key_link_end(struct key *keyring, |
1383 | const struct keyring_index_key *index_key, | |
b2a4df20 | 1384 | struct assoc_array_edit *edit) |
f70e2e06 | 1385 | __releases(&keyring->sem) |
3be59f74 | 1386 | __releases(&keyring_serialise_link_lock) |
f70e2e06 | 1387 | { |
16feef43 | 1388 | BUG_ON(index_key->type == NULL); |
b2a4df20 | 1389 | kenter("%d,%s,", keyring->serial, index_key->type->name); |
f70e2e06 | 1390 | |
ca4da5dd CIK |
1391 | if (edit) { |
1392 | if (!edit->dead_leaf) { | |
1393 | key_payload_reserve(keyring, | |
1394 | keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1395 | } | |
b2a4df20 | 1396 | assoc_array_cancel_edit(edit); |
f70e2e06 DH |
1397 | } |
1398 | up_write(&keyring->sem); | |
df593ee2 DH |
1399 | |
1400 | if (index_key->type == &key_type_keyring) | |
1401 | mutex_unlock(&keyring_serialise_link_lock); | |
f70e2e06 | 1402 | } |
1da177e4 | 1403 | |
5ac7eace DH |
1404 | /* |
1405 | * Check addition of keys to restricted keyrings. | |
1406 | */ | |
1407 | static int __key_link_check_restriction(struct key *keyring, struct key *key) | |
1408 | { | |
2b6aa412 | 1409 | if (!keyring->restrict_link || !keyring->restrict_link->check) |
5ac7eace | 1410 | return 0; |
2b6aa412 MM |
1411 | return keyring->restrict_link->check(keyring, key->type, &key->payload, |
1412 | keyring->restrict_link->key); | |
5ac7eace DH |
1413 | } |
1414 | ||
973c9f4f DH |
1415 | /** |
1416 | * key_link - Link a key to a keyring | |
1417 | * @keyring: The keyring to make the link in. | |
1418 | * @key: The key to link to. | |
1419 | * | |
1420 | * Make a link in a keyring to a key, such that the keyring holds a reference | |
1421 | * on that key and the key can potentially be found by searching that keyring. | |
1422 | * | |
1423 | * This function will write-lock the keyring's semaphore and will consume some | |
1424 | * of the user's key data quota to hold the link. | |
1425 | * | |
1426 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, | |
1427 | * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is | |
1428 | * full, -EDQUOT if there is insufficient key data quota remaining to add | |
1429 | * another link or -ENOMEM if there's insufficient memory. | |
1430 | * | |
1431 | * It is assumed that the caller has checked that it is permitted for a link to | |
1432 | * be made (the keyring should have Write permission and the key Link | |
1433 | * permission). | |
1da177e4 LT |
1434 | */ |
1435 | int key_link(struct key *keyring, struct key *key) | |
1436 | { | |
df593ee2 | 1437 | struct assoc_array_edit *edit = NULL; |
1da177e4 LT |
1438 | int ret; |
1439 | ||
fff29291 | 1440 | kenter("{%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
b2a4df20 | 1441 | |
1da177e4 LT |
1442 | key_check(keyring); |
1443 | key_check(key); | |
1444 | ||
df593ee2 DH |
1445 | ret = __key_link_lock(keyring, &key->index_key); |
1446 | if (ret < 0) | |
1447 | goto error; | |
1448 | ||
b2a4df20 | 1449 | ret = __key_link_begin(keyring, &key->index_key, &edit); |
df593ee2 DH |
1450 | if (ret < 0) |
1451 | goto error_end; | |
1da177e4 | 1452 | |
df593ee2 DH |
1453 | kdebug("begun {%d,%d}", keyring->serial, refcount_read(&keyring->usage)); |
1454 | ret = __key_link_check_restriction(keyring, key); | |
1455 | if (ret == 0) | |
1456 | ret = __key_link_check_live_key(keyring, key); | |
1457 | if (ret == 0) | |
1458 | __key_link(key, &edit); | |
1da177e4 | 1459 | |
df593ee2 DH |
1460 | error_end: |
1461 | __key_link_end(keyring, &key->index_key, edit); | |
1462 | error: | |
fff29291 | 1463 | kleave(" = %d {%d,%d}", ret, keyring->serial, refcount_read(&keyring->usage)); |
1da177e4 | 1464 | return ret; |
f70e2e06 | 1465 | } |
1da177e4 LT |
1466 | EXPORT_SYMBOL(key_link); |
1467 | ||
eb0f68cb DH |
1468 | /* |
1469 | * Lock a keyring for unlink. | |
1470 | */ | |
1471 | static int __key_unlink_lock(struct key *keyring) | |
1472 | __acquires(&keyring->sem) | |
1473 | { | |
1474 | if (keyring->type != &key_type_keyring) | |
1475 | return -ENOTDIR; | |
1476 | ||
1477 | down_write(&keyring->sem); | |
1478 | return 0; | |
1479 | } | |
1480 | ||
1481 | /* | |
1482 | * Begin the process of unlinking a key from a keyring. | |
1483 | */ | |
1484 | static int __key_unlink_begin(struct key *keyring, struct key *key, | |
1485 | struct assoc_array_edit **_edit) | |
1486 | { | |
1487 | struct assoc_array_edit *edit; | |
1488 | ||
1489 | BUG_ON(*_edit != NULL); | |
1490 | ||
1491 | edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops, | |
1492 | &key->index_key); | |
1493 | if (IS_ERR(edit)) | |
1494 | return PTR_ERR(edit); | |
1495 | ||
1496 | if (!edit) | |
1497 | return -ENOENT; | |
1498 | ||
1499 | *_edit = edit; | |
1500 | return 0; | |
1501 | } | |
1502 | ||
1503 | /* | |
1504 | * Apply an unlink change. | |
1505 | */ | |
1506 | static void __key_unlink(struct key *keyring, struct key *key, | |
1507 | struct assoc_array_edit **_edit) | |
1508 | { | |
1509 | assoc_array_apply_edit(*_edit); | |
1510 | *_edit = NULL; | |
1511 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1512 | } | |
1513 | ||
1514 | /* | |
1515 | * Finish unlinking a key from to a keyring. | |
1516 | */ | |
1517 | static void __key_unlink_end(struct key *keyring, | |
1518 | struct key *key, | |
1519 | struct assoc_array_edit *edit) | |
1520 | __releases(&keyring->sem) | |
1521 | { | |
1522 | if (edit) | |
1523 | assoc_array_cancel_edit(edit); | |
1524 | up_write(&keyring->sem); | |
1525 | } | |
1526 | ||
973c9f4f DH |
1527 | /** |
1528 | * key_unlink - Unlink the first link to a key from a keyring. | |
1529 | * @keyring: The keyring to remove the link from. | |
1530 | * @key: The key the link is to. | |
1531 | * | |
1532 | * Remove a link from a keyring to a key. | |
1533 | * | |
1534 | * This function will write-lock the keyring's semaphore. | |
1535 | * | |
1536 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1537 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1538 | * memory. | |
1539 | * | |
1540 | * It is assumed that the caller has checked that it is permitted for a link to | |
1541 | * be removed (the keyring should have Write permission; no permissions are | |
1542 | * required on the key). | |
1da177e4 LT |
1543 | */ |
1544 | int key_unlink(struct key *keyring, struct key *key) | |
1545 | { | |
eb0f68cb | 1546 | struct assoc_array_edit *edit = NULL; |
b2a4df20 | 1547 | int ret; |
1da177e4 LT |
1548 | |
1549 | key_check(keyring); | |
1550 | key_check(key); | |
1551 | ||
eb0f68cb DH |
1552 | ret = __key_unlink_lock(keyring); |
1553 | if (ret < 0) | |
1554 | return ret; | |
1da177e4 | 1555 | |
eb0f68cb DH |
1556 | ret = __key_unlink_begin(keyring, key, &edit); |
1557 | if (ret == 0) | |
1558 | __key_unlink(keyring, key, &edit); | |
1559 | __key_unlink_end(keyring, key, edit); | |
b2a4df20 | 1560 | return ret; |
a8b17ed0 | 1561 | } |
1da177e4 | 1562 | EXPORT_SYMBOL(key_unlink); |
1da177e4 | 1563 | |
ed0ac5c7 DH |
1564 | /** |
1565 | * key_move - Move a key from one keyring to another | |
1566 | * @key: The key to move | |
1567 | * @from_keyring: The keyring to remove the link from. | |
1568 | * @to_keyring: The keyring to make the link in. | |
1569 | * @flags: Qualifying flags, such as KEYCTL_MOVE_EXCL. | |
1570 | * | |
1571 | * Make a link in @to_keyring to a key, such that the keyring holds a reference | |
1572 | * on that key and the key can potentially be found by searching that keyring | |
1573 | * whilst simultaneously removing a link to the key from @from_keyring. | |
1574 | * | |
1575 | * This function will write-lock both keyring's semaphores and will consume | |
1576 | * some of the user's key data quota to hold the link on @to_keyring. | |
1577 | * | |
1578 | * Returns 0 if successful, -ENOTDIR if either keyring isn't a keyring, | |
1579 | * -EKEYREVOKED if either keyring has been revoked, -ENFILE if the second | |
1580 | * keyring is full, -EDQUOT if there is insufficient key data quota remaining | |
1581 | * to add another link or -ENOMEM if there's insufficient memory. If | |
1582 | * KEYCTL_MOVE_EXCL is set, then -EEXIST will be returned if there's already a | |
1583 | * matching key in @to_keyring. | |
1584 | * | |
1585 | * It is assumed that the caller has checked that it is permitted for a link to | |
1586 | * be made (the keyring should have Write permission and the key Link | |
1587 | * permission). | |
1588 | */ | |
1589 | int key_move(struct key *key, | |
1590 | struct key *from_keyring, | |
1591 | struct key *to_keyring, | |
1592 | unsigned int flags) | |
1593 | { | |
1594 | struct assoc_array_edit *from_edit = NULL, *to_edit = NULL; | |
1595 | int ret; | |
1596 | ||
1597 | kenter("%d,%d,%d", key->serial, from_keyring->serial, to_keyring->serial); | |
1598 | ||
1599 | if (from_keyring == to_keyring) | |
1600 | return 0; | |
1601 | ||
1602 | key_check(key); | |
1603 | key_check(from_keyring); | |
1604 | key_check(to_keyring); | |
1605 | ||
1606 | ret = __key_move_lock(from_keyring, to_keyring, &key->index_key); | |
1607 | if (ret < 0) | |
1608 | goto out; | |
1609 | ret = __key_unlink_begin(from_keyring, key, &from_edit); | |
1610 | if (ret < 0) | |
b2a4df20 | 1611 | goto error; |
ed0ac5c7 DH |
1612 | ret = __key_link_begin(to_keyring, &key->index_key, &to_edit); |
1613 | if (ret < 0) | |
b2a4df20 | 1614 | goto error; |
1da177e4 | 1615 | |
ed0ac5c7 DH |
1616 | ret = -EEXIST; |
1617 | if (to_edit->dead_leaf && (flags & KEYCTL_MOVE_EXCL)) | |
1618 | goto error; | |
1da177e4 | 1619 | |
ed0ac5c7 DH |
1620 | ret = __key_link_check_restriction(to_keyring, key); |
1621 | if (ret < 0) | |
1622 | goto error; | |
1623 | ret = __key_link_check_live_key(to_keyring, key); | |
1624 | if (ret < 0) | |
1625 | goto error; | |
1626 | ||
1627 | __key_unlink(from_keyring, key, &from_edit); | |
1628 | __key_link(key, &to_edit); | |
76d8aeab | 1629 | error: |
ed0ac5c7 DH |
1630 | __key_link_end(to_keyring, &key->index_key, to_edit); |
1631 | __key_unlink_end(from_keyring, key, from_edit); | |
1632 | out: | |
1633 | kleave(" = %d", ret); | |
b2a4df20 | 1634 | return ret; |
a8b17ed0 | 1635 | } |
ed0ac5c7 | 1636 | EXPORT_SYMBOL(key_move); |
1da177e4 | 1637 | |
973c9f4f DH |
1638 | /** |
1639 | * keyring_clear - Clear a keyring | |
1640 | * @keyring: The keyring to clear. | |
1641 | * | |
1642 | * Clear the contents of the specified keyring. | |
1643 | * | |
1644 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1645 | */ |
1646 | int keyring_clear(struct key *keyring) | |
1647 | { | |
b2a4df20 | 1648 | struct assoc_array_edit *edit; |
76d8aeab | 1649 | int ret; |
1da177e4 | 1650 | |
b2a4df20 DH |
1651 | if (keyring->type != &key_type_keyring) |
1652 | return -ENOTDIR; | |
1da177e4 | 1653 | |
b2a4df20 | 1654 | down_write(&keyring->sem); |
1da177e4 | 1655 | |
b2a4df20 DH |
1656 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1657 | if (IS_ERR(edit)) { | |
1658 | ret = PTR_ERR(edit); | |
1659 | } else { | |
1660 | if (edit) | |
1661 | assoc_array_apply_edit(edit); | |
1662 | key_payload_reserve(keyring, 0); | |
1da177e4 LT |
1663 | ret = 0; |
1664 | } | |
1665 | ||
b2a4df20 | 1666 | up_write(&keyring->sem); |
1da177e4 | 1667 | return ret; |
a8b17ed0 | 1668 | } |
1da177e4 | 1669 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1670 | |
31204ed9 | 1671 | /* |
973c9f4f DH |
1672 | * Dispose of the links from a revoked keyring. |
1673 | * | |
1674 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1675 | */ |
1676 | static void keyring_revoke(struct key *keyring) | |
1677 | { | |
b2a4df20 | 1678 | struct assoc_array_edit *edit; |
f0641cba | 1679 | |
b2a4df20 DH |
1680 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1681 | if (!IS_ERR(edit)) { | |
1682 | if (edit) | |
1683 | assoc_array_apply_edit(edit); | |
1684 | key_payload_reserve(keyring, 0); | |
1685 | } | |
1686 | } | |
31204ed9 | 1687 | |
62fe3182 | 1688 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1689 | { |
1690 | struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1691 | time64_t *limit = iterator_data; |
31204ed9 | 1692 | |
b2a4df20 DH |
1693 | if (key_is_dead(key, *limit)) |
1694 | return false; | |
1695 | key_get(key); | |
1696 | return true; | |
a8b17ed0 | 1697 | } |
5d135440 | 1698 | |
62fe3182 DH |
1699 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1700 | { | |
1701 | const struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1702 | time64_t *limit = iterator_data; |
62fe3182 DH |
1703 | |
1704 | key_check(key); | |
1705 | return key_is_dead(key, *limit); | |
1706 | } | |
1707 | ||
5d135440 | 1708 | /* |
62fe3182 | 1709 | * Garbage collect pointers from a keyring. |
973c9f4f | 1710 | * |
62fe3182 DH |
1711 | * Not called with any locks held. The keyring's key struct will not be |
1712 | * deallocated under us as only our caller may deallocate it. | |
5d135440 | 1713 | */ |
074d5898 | 1714 | void keyring_gc(struct key *keyring, time64_t limit) |
5d135440 | 1715 | { |
62fe3182 DH |
1716 | int result; |
1717 | ||
1718 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1719 | |
62fe3182 DH |
1720 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1721 | (1 << KEY_FLAG_REVOKED))) | |
1722 | goto dont_gc; | |
1723 | ||
1724 | /* scan the keyring looking for dead keys */ | |
1725 | rcu_read_lock(); | |
1726 | result = assoc_array_iterate(&keyring->keys, | |
1727 | keyring_gc_check_iterator, &limit); | |
1728 | rcu_read_unlock(); | |
1729 | if (result == true) | |
1730 | goto do_gc; | |
1731 | ||
1732 | dont_gc: | |
1733 | kleave(" [no gc]"); | |
1734 | return; | |
1735 | ||
1736 | do_gc: | |
5d135440 | 1737 | down_write(&keyring->sem); |
b2a4df20 | 1738 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1739 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1740 | up_write(&keyring->sem); |
62fe3182 | 1741 | kleave(" [gc]"); |
5d135440 | 1742 | } |
2b6aa412 MM |
1743 | |
1744 | /* | |
1745 | * Garbage collect restriction pointers from a keyring. | |
1746 | * | |
1747 | * Keyring restrictions are associated with a key type, and must be cleaned | |
1748 | * up if the key type is unregistered. The restriction is altered to always | |
1749 | * reject additional keys so a keyring cannot be opened up by unregistering | |
1750 | * a key type. | |
1751 | * | |
1752 | * Not called with any keyring locks held. The keyring's key struct will not | |
1753 | * be deallocated under us as only our caller may deallocate it. | |
1754 | * | |
1755 | * The caller is required to hold key_types_sem and dead_type->sem. This is | |
1756 | * fulfilled by key_gc_keytype() holding the locks on behalf of | |
1757 | * key_garbage_collector(), which it invokes on a workqueue. | |
1758 | */ | |
1759 | void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) | |
1760 | { | |
1761 | struct key_restriction *keyres; | |
1762 | ||
1763 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
1764 | ||
1765 | /* | |
1766 | * keyring->restrict_link is only assigned at key allocation time | |
1767 | * or with the key type locked, so the only values that could be | |
1768 | * concurrently assigned to keyring->restrict_link are for key | |
1769 | * types other than dead_type. Given this, it's ok to check | |
1770 | * the key type before acquiring keyring->sem. | |
1771 | */ | |
1772 | if (!dead_type || !keyring->restrict_link || | |
1773 | keyring->restrict_link->keytype != dead_type) { | |
1774 | kleave(" [no restriction gc]"); | |
1775 | return; | |
1776 | } | |
1777 | ||
1778 | /* Lock the keyring to ensure that a link is not in progress */ | |
1779 | down_write(&keyring->sem); | |
1780 | ||
1781 | keyres = keyring->restrict_link; | |
1782 | ||
1783 | keyres->check = restrict_link_reject; | |
1784 | ||
1785 | key_put(keyres->key); | |
1786 | keyres->key = NULL; | |
1787 | keyres->keytype = NULL; | |
1788 | ||
1789 | up_write(&keyring->sem); | |
1790 | ||
1791 | kleave(" [restriction gc]"); | |
1792 | } |