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 | 454 | size_t count; |
796e46f9 | 455 | key_serial_t *buffer; |
b2a4df20 DH |
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); | |
b2a4df20 DH |
462 | |
463 | kenter("{%s,%d},,{%zu/%zu}", | |
e645016a | 464 | key->type->name, key->serial, ctx->count, ctx->buflen); |
b2a4df20 | 465 | |
e645016a | 466 | if (ctx->count >= ctx->buflen) |
b2a4df20 DH |
467 | return 1; |
468 | ||
d3ec10aa | 469 | *ctx->buffer++ = key->serial; |
b2a4df20 DH |
470 | ctx->count += sizeof(key->serial); |
471 | return 0; | |
472 | } | |
473 | ||
1da177e4 | 474 | /* |
973c9f4f DH |
475 | * Read a list of key IDs from the keyring's contents in binary form |
476 | * | |
b2a4df20 DH |
477 | * The keyring's semaphore is read-locked by the caller. This prevents someone |
478 | * from modifying it under us - which could cause us to read key IDs multiple | |
479 | * times. | |
1da177e4 LT |
480 | */ |
481 | static long keyring_read(const struct key *keyring, | |
796e46f9 | 482 | char *buffer, size_t buflen) |
1da177e4 | 483 | { |
b2a4df20 | 484 | struct keyring_read_iterator_context ctx; |
3239b6f2 | 485 | long ret; |
1da177e4 | 486 | |
b2a4df20 DH |
487 | kenter("{%d},,%zu", key_serial(keyring), buflen); |
488 | ||
489 | if (buflen & (sizeof(key_serial_t) - 1)) | |
490 | return -EINVAL; | |
491 | ||
3239b6f2 EB |
492 | /* Copy as many key IDs as fit into the buffer */ |
493 | if (buffer && buflen) { | |
796e46f9 | 494 | ctx.buffer = (key_serial_t *)buffer; |
3239b6f2 EB |
495 | ctx.buflen = buflen; |
496 | ctx.count = 0; | |
497 | ret = assoc_array_iterate(&keyring->keys, | |
498 | keyring_read_iterator, &ctx); | |
499 | if (ret < 0) { | |
500 | kleave(" = %ld [iterate]", ret); | |
501 | return ret; | |
502 | } | |
1da177e4 LT |
503 | } |
504 | ||
3239b6f2 EB |
505 | /* Return the size of the buffer needed */ |
506 | ret = keyring->keys.nr_leaves_on_tree * sizeof(key_serial_t); | |
507 | if (ret <= buflen) | |
508 | kleave("= %ld [ok]", ret); | |
509 | else | |
510 | kleave("= %ld [buffer too small]", ret); | |
511 | return ret; | |
a8b17ed0 | 512 | } |
1da177e4 | 513 | |
028db3e2 LT |
514 | /* |
515 | * Allocate a keyring and link into the destination keyring. | |
1da177e4 | 516 | */ |
9a56c2db | 517 | struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid, |
028db3e2 | 518 | const struct cred *cred, key_perm_t perm, |
5ac7eace | 519 | unsigned long flags, |
2b6aa412 | 520 | struct key_restriction *restrict_link, |
5ac7eace | 521 | struct key *dest) |
1da177e4 LT |
522 | { |
523 | struct key *keyring; | |
524 | int ret; | |
525 | ||
526 | keyring = key_alloc(&key_type_keyring, description, | |
028db3e2 | 527 | uid, gid, cred, perm, flags, restrict_link); |
1da177e4 | 528 | if (!IS_ERR(keyring)) { |
3e30148c | 529 | ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL); |
1da177e4 LT |
530 | if (ret < 0) { |
531 | key_put(keyring); | |
532 | keyring = ERR_PTR(ret); | |
533 | } | |
534 | } | |
535 | ||
536 | return keyring; | |
a8b17ed0 | 537 | } |
f8aa23a5 | 538 | EXPORT_SYMBOL(keyring_alloc); |
1da177e4 | 539 | |
5ac7eace DH |
540 | /** |
541 | * restrict_link_reject - Give -EPERM to restrict link | |
542 | * @keyring: The keyring being added to. | |
543 | * @type: The type of key being added. | |
5ac7eace | 544 | * @payload: The payload of the key intended to be added. |
9fd16537 | 545 | * @restriction_key: Keys providing additional data for evaluating restriction. |
5ac7eace DH |
546 | * |
547 | * Reject the addition of any links to a keyring. It can be overridden by | |
548 | * passing KEY_ALLOC_BYPASS_RESTRICTION to key_instantiate_and_link() when | |
549 | * adding a key to a keyring. | |
550 | * | |
2b6aa412 MM |
551 | * This is meant to be stored in a key_restriction structure which is passed |
552 | * in the restrict_link parameter to keyring_alloc(). | |
5ac7eace DH |
553 | */ |
554 | int restrict_link_reject(struct key *keyring, | |
555 | const struct key_type *type, | |
aaf66c88 MM |
556 | const union key_payload *payload, |
557 | struct key *restriction_key) | |
5ac7eace DH |
558 | { |
559 | return -EPERM; | |
560 | } | |
561 | ||
c06cfb08 DH |
562 | /* |
563 | * By default, we keys found by getting an exact match on their descriptions. | |
564 | */ | |
0c903ab6 DH |
565 | bool key_default_cmp(const struct key *key, |
566 | const struct key_match_data *match_data) | |
c06cfb08 DH |
567 | { |
568 | return strcmp(key->description, match_data->raw_data) == 0; | |
569 | } | |
570 | ||
b2a4df20 DH |
571 | /* |
572 | * Iteration function to consider each key found. | |
1da177e4 | 573 | */ |
b2a4df20 | 574 | static int keyring_search_iterator(const void *object, void *iterator_data) |
1da177e4 | 575 | { |
b2a4df20 DH |
576 | struct keyring_search_context *ctx = iterator_data; |
577 | const struct key *key = keyring_ptr_to_key(object); | |
363b02da DH |
578 | unsigned long kflags = READ_ONCE(key->flags); |
579 | short state = READ_ONCE(key->state); | |
1da177e4 | 580 | |
b2a4df20 | 581 | kenter("{%d}", key->serial); |
1da177e4 | 582 | |
b2a4df20 DH |
583 | /* ignore keys not of this type */ |
584 | if (key->type != ctx->index_key.type) { | |
585 | kleave(" = 0 [!type]"); | |
586 | return 0; | |
29db9190 | 587 | } |
1da177e4 | 588 | |
b2a4df20 DH |
589 | /* skip invalidated, revoked and expired keys */ |
590 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { | |
074d5898 | 591 | time64_t expiry = READ_ONCE(key->expiry); |
9d6c8711 | 592 | |
b2a4df20 DH |
593 | if (kflags & ((1 << KEY_FLAG_INVALIDATED) | |
594 | (1 << KEY_FLAG_REVOKED))) { | |
595 | ctx->result = ERR_PTR(-EKEYREVOKED); | |
596 | kleave(" = %d [invrev]", ctx->skipped_ret); | |
597 | goto skipped; | |
598 | } | |
1da177e4 | 599 | |
074d5898 | 600 | if (expiry && ctx->now >= expiry) { |
0b0a8415 DH |
601 | if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED)) |
602 | ctx->result = ERR_PTR(-EKEYEXPIRED); | |
b2a4df20 DH |
603 | kleave(" = %d [expire]", ctx->skipped_ret); |
604 | goto skipped; | |
605 | } | |
606 | } | |
664cceb0 | 607 | |
b2a4df20 | 608 | /* keys that don't match */ |
46291959 | 609 | if (!ctx->match_data.cmp(key, &ctx->match_data)) { |
b2a4df20 DH |
610 | kleave(" = 0 [!match]"); |
611 | return 0; | |
612 | } | |
dceba994 | 613 | |
b2a4df20 DH |
614 | /* key must have search permissions */ |
615 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
616 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 617 | ctx->cred, KEY_NEED_SEARCH) < 0) { |
b2a4df20 DH |
618 | ctx->result = ERR_PTR(-EACCES); |
619 | kleave(" = %d [!perm]", ctx->skipped_ret); | |
620 | goto skipped; | |
dceba994 KC |
621 | } |
622 | ||
b2a4df20 DH |
623 | if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) { |
624 | /* we set a different error code if we pass a negative key */ | |
363b02da DH |
625 | if (state < 0) { |
626 | ctx->result = ERR_PTR(state); | |
b2a4df20 DH |
627 | kleave(" = %d [neg]", ctx->skipped_ret); |
628 | goto skipped; | |
629 | } | |
630 | } | |
1da177e4 | 631 | |
b2a4df20 DH |
632 | /* Found */ |
633 | ctx->result = make_key_ref(key, ctx->possessed); | |
634 | kleave(" = 1 [found]"); | |
635 | return 1; | |
1da177e4 | 636 | |
b2a4df20 DH |
637 | skipped: |
638 | return ctx->skipped_ret; | |
639 | } | |
1da177e4 | 640 | |
b2a4df20 DH |
641 | /* |
642 | * Search inside a keyring for a key. We can search by walking to it | |
643 | * directly based on its index-key or we can iterate over the entire | |
644 | * tree looking for it, based on the match function. | |
645 | */ | |
646 | static int search_keyring(struct key *keyring, struct keyring_search_context *ctx) | |
647 | { | |
46291959 | 648 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) { |
b2a4df20 DH |
649 | const void *object; |
650 | ||
651 | object = assoc_array_find(&keyring->keys, | |
652 | &keyring_assoc_array_ops, | |
653 | &ctx->index_key); | |
654 | return object ? ctx->iterator(object, ctx) : 0; | |
655 | } | |
656 | return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx); | |
657 | } | |
1da177e4 | 658 | |
b2a4df20 DH |
659 | /* |
660 | * Search a tree of keyrings that point to other keyrings up to the maximum | |
661 | * depth. | |
662 | */ | |
663 | static bool search_nested_keyrings(struct key *keyring, | |
664 | struct keyring_search_context *ctx) | |
665 | { | |
666 | struct { | |
667 | struct key *keyring; | |
668 | struct assoc_array_node *node; | |
669 | int slot; | |
670 | } stack[KEYRING_SEARCH_MAX_DEPTH]; | |
1da177e4 | 671 | |
b2a4df20 DH |
672 | struct assoc_array_shortcut *shortcut; |
673 | struct assoc_array_node *node; | |
674 | struct assoc_array_ptr *ptr; | |
675 | struct key *key; | |
676 | int sp = 0, slot; | |
1da177e4 | 677 | |
b2a4df20 DH |
678 | kenter("{%d},{%s,%s}", |
679 | keyring->serial, | |
680 | ctx->index_key.type->name, | |
681 | ctx->index_key.description); | |
1da177e4 | 682 | |
054f6180 DH |
683 | #define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK) |
684 | BUG_ON((ctx->flags & STATE_CHECKS) == 0 || | |
685 | (ctx->flags & STATE_CHECKS) == STATE_CHECKS); | |
686 | ||
f771fde8 DH |
687 | if (ctx->index_key.description) |
688 | key_set_index_key(&ctx->index_key); | |
689 | ||
b2a4df20 DH |
690 | /* Check to see if this top-level keyring is what we are looking for |
691 | * and whether it is valid or not. | |
692 | */ | |
46291959 | 693 | if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE || |
b2a4df20 DH |
694 | keyring_compare_object(keyring, &ctx->index_key)) { |
695 | ctx->skipped_ret = 2; | |
b2a4df20 DH |
696 | switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) { |
697 | case 1: | |
78b7280c | 698 | goto found; |
b2a4df20 DH |
699 | case 2: |
700 | return false; | |
701 | default: | |
702 | break; | |
1da177e4 | 703 | } |
b2a4df20 | 704 | } |
1da177e4 | 705 | |
b2a4df20 | 706 | ctx->skipped_ret = 0; |
b2a4df20 DH |
707 | |
708 | /* Start processing a new keyring */ | |
709 | descend_to_keyring: | |
710 | kdebug("descend to %d", keyring->serial); | |
711 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
712 | (1 << KEY_FLAG_REVOKED))) | |
713 | goto not_this_keyring; | |
714 | ||
715 | /* Search through the keys in this keyring before its searching its | |
716 | * subtrees. | |
717 | */ | |
718 | if (search_keyring(keyring, ctx)) | |
1da177e4 | 719 | goto found; |
1da177e4 | 720 | |
b2a4df20 DH |
721 | /* Then manually iterate through the keyrings nested in this one. |
722 | * | |
723 | * Start from the root node of the index tree. Because of the way the | |
724 | * hash function has been set up, keyrings cluster on the leftmost | |
725 | * branch of the root node (root slot 0) or in the root node itself. | |
726 | * Non-keyrings avoid the leftmost branch of the root entirely (root | |
727 | * slots 1-15). | |
728 | */ | |
dcf49dbc DH |
729 | if (!(ctx->flags & KEYRING_SEARCH_RECURSE)) |
730 | goto not_this_keyring; | |
731 | ||
381f20fc | 732 | ptr = READ_ONCE(keyring->keys.root); |
b2a4df20 DH |
733 | if (!ptr) |
734 | goto not_this_keyring; | |
1da177e4 | 735 | |
b2a4df20 DH |
736 | if (assoc_array_ptr_is_shortcut(ptr)) { |
737 | /* If the root is a shortcut, either the keyring only contains | |
738 | * keyring pointers (everything clusters behind root slot 0) or | |
739 | * doesn't contain any keyring pointers. | |
1da177e4 | 740 | */ |
b2a4df20 | 741 | shortcut = assoc_array_ptr_to_shortcut(ptr); |
b2a4df20 DH |
742 | if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0) |
743 | goto not_this_keyring; | |
744 | ||
381f20fc | 745 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 DH |
746 | node = assoc_array_ptr_to_node(ptr); |
747 | goto begin_node; | |
748 | } | |
749 | ||
750 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
751 | ptr = node->slots[0]; |
752 | if (!assoc_array_ptr_is_meta(ptr)) | |
753 | goto begin_node; | |
754 | ||
755 | descend_to_node: | |
756 | /* Descend to a more distal node in this keyring's content tree and go | |
757 | * through that. | |
758 | */ | |
759 | kdebug("descend"); | |
760 | if (assoc_array_ptr_is_shortcut(ptr)) { | |
761 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 762 | ptr = READ_ONCE(shortcut->next_node); |
b2a4df20 | 763 | BUG_ON(!assoc_array_ptr_is_node(ptr)); |
b2a4df20 | 764 | } |
9c5e45df | 765 | node = assoc_array_ptr_to_node(ptr); |
b2a4df20 DH |
766 | |
767 | begin_node: | |
768 | kdebug("begin_node"); | |
b2a4df20 DH |
769 | slot = 0; |
770 | ascend_to_node: | |
771 | /* Go through the slots in a node */ | |
772 | for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) { | |
381f20fc | 773 | ptr = READ_ONCE(node->slots[slot]); |
b2a4df20 DH |
774 | |
775 | if (assoc_array_ptr_is_meta(ptr) && node->back_pointer) | |
776 | goto descend_to_node; | |
777 | ||
778 | if (!keyring_ptr_is_keyring(ptr)) | |
76d8aeab | 779 | continue; |
1da177e4 | 780 | |
b2a4df20 DH |
781 | key = keyring_ptr_to_key(ptr); |
782 | ||
783 | if (sp >= KEYRING_SEARCH_MAX_DEPTH) { | |
784 | if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) { | |
785 | ctx->result = ERR_PTR(-ELOOP); | |
786 | return false; | |
787 | } | |
788 | goto not_this_keyring; | |
789 | } | |
790 | ||
791 | /* Search a nested keyring */ | |
792 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) && | |
793 | key_task_permission(make_key_ref(key, ctx->possessed), | |
f5895943 | 794 | ctx->cred, KEY_NEED_SEARCH) < 0) |
76d8aeab | 795 | continue; |
1da177e4 LT |
796 | |
797 | /* stack the current position */ | |
31d5a79d | 798 | stack[sp].keyring = keyring; |
b2a4df20 DH |
799 | stack[sp].node = node; |
800 | stack[sp].slot = slot; | |
1da177e4 LT |
801 | sp++; |
802 | ||
803 | /* begin again with the new keyring */ | |
804 | keyring = key; | |
b2a4df20 DH |
805 | goto descend_to_keyring; |
806 | } | |
807 | ||
808 | /* We've dealt with all the slots in the current node, so now we need | |
809 | * to ascend to the parent and continue processing there. | |
810 | */ | |
381f20fc | 811 | ptr = READ_ONCE(node->back_pointer); |
b2a4df20 DH |
812 | slot = node->parent_slot; |
813 | ||
814 | if (ptr && assoc_array_ptr_is_shortcut(ptr)) { | |
815 | shortcut = assoc_array_ptr_to_shortcut(ptr); | |
381f20fc | 816 | ptr = READ_ONCE(shortcut->back_pointer); |
b2a4df20 DH |
817 | slot = shortcut->parent_slot; |
818 | } | |
819 | if (!ptr) | |
820 | goto not_this_keyring; | |
821 | node = assoc_array_ptr_to_node(ptr); | |
b2a4df20 DH |
822 | slot++; |
823 | ||
824 | /* If we've ascended to the root (zero backpointer), we must have just | |
825 | * finished processing the leftmost branch rather than the root slots - | |
826 | * so there can't be any more keyrings for us to find. | |
827 | */ | |
828 | if (node->back_pointer) { | |
829 | kdebug("ascend %d", slot); | |
830 | goto ascend_to_node; | |
1da177e4 LT |
831 | } |
832 | ||
b2a4df20 DH |
833 | /* The keyring we're looking at was disqualified or didn't contain a |
834 | * matching key. | |
835 | */ | |
664cceb0 | 836 | not_this_keyring: |
b2a4df20 DH |
837 | kdebug("not_this_keyring %d", sp); |
838 | if (sp <= 0) { | |
839 | kleave(" = false"); | |
840 | return false; | |
1da177e4 LT |
841 | } |
842 | ||
b2a4df20 DH |
843 | /* Resume the processing of a keyring higher up in the tree */ |
844 | sp--; | |
845 | keyring = stack[sp].keyring; | |
846 | node = stack[sp].node; | |
847 | slot = stack[sp].slot + 1; | |
848 | kdebug("ascend to %d [%d]", keyring->serial, slot); | |
849 | goto ascend_to_node; | |
1da177e4 | 850 | |
b2a4df20 | 851 | /* We found a viable match */ |
664cceb0 | 852 | found: |
b2a4df20 | 853 | key = key_ref_to_ptr(ctx->result); |
1da177e4 | 854 | key_check(key); |
b2a4df20 | 855 | if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) { |
074d5898 BW |
856 | key->last_used_at = ctx->now; |
857 | keyring->last_used_at = ctx->now; | |
b2a4df20 | 858 | while (sp > 0) |
074d5898 | 859 | stack[--sp].keyring->last_used_at = ctx->now; |
b2a4df20 DH |
860 | } |
861 | kleave(" = true"); | |
862 | return true; | |
863 | } | |
864 | ||
865 | /** | |
e59428f7 | 866 | * keyring_search_rcu - Search a keyring tree for a matching key under RCU |
b2a4df20 DH |
867 | * @keyring_ref: A pointer to the keyring with possession indicator. |
868 | * @ctx: The keyring search context. | |
869 | * | |
870 | * Search the supplied keyring tree for a key that matches the criteria given. | |
871 | * The root keyring and any linked keyrings must grant Search permission to the | |
872 | * caller to be searchable and keys can only be found if they too grant Search | |
873 | * to the caller. The possession flag on the root keyring pointer controls use | |
874 | * of the possessor bits in permissions checking of the entire tree. In | |
875 | * addition, the LSM gets to forbid keyring searches and key matches. | |
876 | * | |
877 | * The search is performed as a breadth-then-depth search up to the prescribed | |
e59428f7 DH |
878 | * limit (KEYRING_SEARCH_MAX_DEPTH). The caller must hold the RCU read lock to |
879 | * prevent keyrings from being destroyed or rearranged whilst they are being | |
880 | * searched. | |
b2a4df20 DH |
881 | * |
882 | * Keys are matched to the type provided and are then filtered by the match | |
883 | * function, which is given the description to use in any way it sees fit. The | |
328c95db | 884 | * match function may use any attributes of a key that it wishes to |
b2a4df20 DH |
885 | * determine the match. Normally the match function from the key type would be |
886 | * used. | |
887 | * | |
888 | * RCU can be used to prevent the keyring key lists from disappearing without | |
889 | * the need to take lots of locks. | |
890 | * | |
891 | * Returns a pointer to the found key and increments the key usage count if | |
892 | * successful; -EAGAIN if no matching keys were found, or if expired or revoked | |
893 | * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the | |
894 | * specified keyring wasn't a keyring. | |
895 | * | |
896 | * In the case of a successful return, the possession attribute from | |
897 | * @keyring_ref is propagated to the returned key reference. | |
898 | */ | |
e59428f7 | 899 | key_ref_t keyring_search_rcu(key_ref_t keyring_ref, |
b2a4df20 DH |
900 | struct keyring_search_context *ctx) |
901 | { | |
902 | struct key *keyring; | |
903 | long err; | |
904 | ||
905 | ctx->iterator = keyring_search_iterator; | |
906 | ctx->possessed = is_key_possessed(keyring_ref); | |
907 | ctx->result = ERR_PTR(-EAGAIN); | |
908 | ||
909 | keyring = key_ref_to_ptr(keyring_ref); | |
910 | key_check(keyring); | |
911 | ||
912 | if (keyring->type != &key_type_keyring) | |
913 | return ERR_PTR(-ENOTDIR); | |
914 | ||
915 | if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) { | |
f5895943 | 916 | err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH); |
b2a4df20 DH |
917 | if (err < 0) |
918 | return ERR_PTR(err); | |
919 | } | |
920 | ||
074d5898 | 921 | ctx->now = ktime_get_real_seconds(); |
b2a4df20 DH |
922 | if (search_nested_keyrings(keyring, ctx)) |
923 | __key_get(key_ref_to_ptr(ctx->result)); | |
b2a4df20 | 924 | return ctx->result; |
a8b17ed0 | 925 | } |
1da177e4 | 926 | |
973c9f4f DH |
927 | /** |
928 | * keyring_search - Search the supplied keyring tree for a matching key | |
929 | * @keyring: The root of the keyring tree to be searched. | |
930 | * @type: The type of keyring we want to find. | |
931 | * @description: The name of the keyring we want to find. | |
dcf49dbc | 932 | * @recurse: True to search the children of @keyring also |
973c9f4f | 933 | * |
e59428f7 | 934 | * As keyring_search_rcu() above, but using the current task's credentials and |
b2a4df20 | 935 | * type's default matching function and preferred search method. |
1da177e4 | 936 | */ |
664cceb0 DH |
937 | key_ref_t keyring_search(key_ref_t keyring, |
938 | struct key_type *type, | |
dcf49dbc DH |
939 | const char *description, |
940 | bool recurse) | |
1da177e4 | 941 | { |
4bdf0bc3 DH |
942 | struct keyring_search_context ctx = { |
943 | .index_key.type = type, | |
944 | .index_key.description = description, | |
ede0fa98 | 945 | .index_key.desc_len = strlen(description), |
4bdf0bc3 | 946 | .cred = current_cred(), |
c06cfb08 | 947 | .match_data.cmp = key_default_cmp, |
46291959 DH |
948 | .match_data.raw_data = description, |
949 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
950 | .flags = KEYRING_SEARCH_DO_STATE_CHECK, | |
4bdf0bc3 | 951 | }; |
46291959 DH |
952 | key_ref_t key; |
953 | int ret; | |
4bdf0bc3 | 954 | |
dcf49dbc DH |
955 | if (recurse) |
956 | ctx.flags |= KEYRING_SEARCH_RECURSE; | |
46291959 DH |
957 | if (type->match_preparse) { |
958 | ret = type->match_preparse(&ctx.match_data); | |
959 | if (ret < 0) | |
960 | return ERR_PTR(ret); | |
961 | } | |
962 | ||
e59428f7 DH |
963 | rcu_read_lock(); |
964 | key = keyring_search_rcu(keyring, &ctx); | |
965 | rcu_read_unlock(); | |
46291959 DH |
966 | |
967 | if (type->match_free) | |
968 | type->match_free(&ctx.match_data); | |
969 | return key; | |
a8b17ed0 | 970 | } |
1da177e4 LT |
971 | EXPORT_SYMBOL(keyring_search); |
972 | ||
6563c91f MM |
973 | static struct key_restriction *keyring_restriction_alloc( |
974 | key_restrict_link_func_t check) | |
975 | { | |
976 | struct key_restriction *keyres = | |
977 | kzalloc(sizeof(struct key_restriction), GFP_KERNEL); | |
978 | ||
979 | if (!keyres) | |
980 | return ERR_PTR(-ENOMEM); | |
981 | ||
982 | keyres->check = check; | |
983 | ||
984 | return keyres; | |
985 | } | |
986 | ||
987 | /* | |
988 | * Semaphore to serialise restriction setup to prevent reference count | |
989 | * cycles through restriction key pointers. | |
990 | */ | |
991 | static DECLARE_RWSEM(keyring_serialise_restrict_sem); | |
992 | ||
993 | /* | |
994 | * Check for restriction cycles that would prevent keyring garbage collection. | |
995 | * keyring_serialise_restrict_sem must be held. | |
996 | */ | |
997 | static bool keyring_detect_restriction_cycle(const struct key *dest_keyring, | |
998 | struct key_restriction *keyres) | |
999 | { | |
1000 | while (keyres && keyres->key && | |
1001 | keyres->key->type == &key_type_keyring) { | |
1002 | if (keyres->key == dest_keyring) | |
1003 | return true; | |
1004 | ||
1005 | keyres = keyres->key->restrict_link; | |
1006 | } | |
1007 | ||
1008 | return false; | |
1009 | } | |
1010 | ||
1011 | /** | |
1012 | * keyring_restrict - Look up and apply a restriction to a keyring | |
9fd16537 DH |
1013 | * @keyring_ref: The keyring to be restricted |
1014 | * @type: The key type that will provide the restriction checker. | |
6563c91f | 1015 | * @restriction: The restriction options to apply to the keyring |
9fd16537 DH |
1016 | * |
1017 | * Look up a keyring and apply a restriction to it. The restriction is managed | |
1018 | * by the specific key type, but can be configured by the options specified in | |
1019 | * the restriction string. | |
6563c91f MM |
1020 | */ |
1021 | int keyring_restrict(key_ref_t keyring_ref, const char *type, | |
1022 | const char *restriction) | |
1023 | { | |
1024 | struct key *keyring; | |
1025 | struct key_type *restrict_type = NULL; | |
1026 | struct key_restriction *restrict_link; | |
1027 | int ret = 0; | |
1028 | ||
1029 | keyring = key_ref_to_ptr(keyring_ref); | |
1030 | key_check(keyring); | |
1031 | ||
1032 | if (keyring->type != &key_type_keyring) | |
1033 | return -ENOTDIR; | |
1034 | ||
1035 | if (!type) { | |
1036 | restrict_link = keyring_restriction_alloc(restrict_link_reject); | |
1037 | } else { | |
1038 | restrict_type = key_type_lookup(type); | |
1039 | ||
1040 | if (IS_ERR(restrict_type)) | |
1041 | return PTR_ERR(restrict_type); | |
1042 | ||
1043 | if (!restrict_type->lookup_restriction) { | |
1044 | ret = -ENOENT; | |
1045 | goto error; | |
1046 | } | |
1047 | ||
1048 | restrict_link = restrict_type->lookup_restriction(restriction); | |
1049 | } | |
1050 | ||
1051 | if (IS_ERR(restrict_link)) { | |
1052 | ret = PTR_ERR(restrict_link); | |
1053 | goto error; | |
1054 | } | |
1055 | ||
1056 | down_write(&keyring->sem); | |
1057 | down_write(&keyring_serialise_restrict_sem); | |
1058 | ||
f7e47677 | 1059 | if (keyring->restrict_link) { |
6563c91f | 1060 | ret = -EEXIST; |
f7e47677 | 1061 | } else if (keyring_detect_restriction_cycle(keyring, restrict_link)) { |
6563c91f | 1062 | ret = -EDEADLK; |
f7e47677 | 1063 | } else { |
6563c91f | 1064 | keyring->restrict_link = restrict_link; |
f7e47677 DH |
1065 | notify_key(keyring, NOTIFY_KEY_SETATTR, 0); |
1066 | } | |
6563c91f MM |
1067 | |
1068 | up_write(&keyring_serialise_restrict_sem); | |
1069 | up_write(&keyring->sem); | |
1070 | ||
1071 | if (ret < 0) { | |
1072 | key_put(restrict_link->key); | |
1073 | kfree(restrict_link); | |
1074 | } | |
1075 | ||
1076 | error: | |
1077 | if (restrict_type) | |
1078 | key_type_put(restrict_type); | |
1079 | ||
1080 | return ret; | |
1081 | } | |
1082 | EXPORT_SYMBOL(keyring_restrict); | |
1083 | ||
1da177e4 | 1084 | /* |
b2a4df20 | 1085 | * Search the given keyring for a key that might be updated. |
973c9f4f DH |
1086 | * |
1087 | * The caller must guarantee that the keyring is a keyring and that the | |
b2a4df20 DH |
1088 | * permission is granted to modify the keyring as no check is made here. The |
1089 | * caller must also hold a lock on the keyring semaphore. | |
973c9f4f DH |
1090 | * |
1091 | * Returns a pointer to the found key with usage count incremented if | |
b2a4df20 DH |
1092 | * successful and returns NULL if not found. Revoked and invalidated keys are |
1093 | * skipped over. | |
973c9f4f DH |
1094 | * |
1095 | * If successful, the possession indicator is propagated from the keyring ref | |
1096 | * to the returned key reference. | |
1da177e4 | 1097 | */ |
b2a4df20 DH |
1098 | key_ref_t find_key_to_update(key_ref_t keyring_ref, |
1099 | const struct keyring_index_key *index_key) | |
1da177e4 | 1100 | { |
664cceb0 | 1101 | struct key *keyring, *key; |
b2a4df20 | 1102 | const void *object; |
1da177e4 | 1103 | |
664cceb0 | 1104 | keyring = key_ref_to_ptr(keyring_ref); |
664cceb0 | 1105 | |
b2a4df20 DH |
1106 | kenter("{%d},{%s,%s}", |
1107 | keyring->serial, index_key->type->name, index_key->description); | |
76d8aeab | 1108 | |
b2a4df20 DH |
1109 | object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops, |
1110 | index_key); | |
1da177e4 | 1111 | |
b2a4df20 DH |
1112 | if (object) |
1113 | goto found; | |
1114 | ||
1115 | kleave(" = NULL"); | |
1116 | return NULL; | |
1da177e4 | 1117 | |
c5b60b5e | 1118 | found: |
b2a4df20 DH |
1119 | key = keyring_ptr_to_key(object); |
1120 | if (key->flags & ((1 << KEY_FLAG_INVALIDATED) | | |
1121 | (1 << KEY_FLAG_REVOKED))) { | |
1122 | kleave(" = NULL [x]"); | |
1123 | return NULL; | |
1124 | } | |
ccc3e6d9 | 1125 | __key_get(key); |
b2a4df20 DH |
1126 | kleave(" = {%d}", key->serial); |
1127 | return make_key_ref(key, is_key_possessed(keyring_ref)); | |
a8b17ed0 | 1128 | } |
1da177e4 | 1129 | |
1da177e4 | 1130 | /* |
973c9f4f DH |
1131 | * Find a keyring with the specified name. |
1132 | * | |
028db3e2 LT |
1133 | * Only keyrings that have nonzero refcount, are not revoked, and are owned by a |
1134 | * user in the current user namespace are considered. If @uid_keyring is %true, | |
1135 | * the keyring additionally must have been allocated as a user or user session | |
1136 | * keyring; otherwise, it must grant Search permission directly to the caller. | |
973c9f4f DH |
1137 | * |
1138 | * Returns a pointer to the keyring with the keyring's refcount having being | |
1139 | * incremented on success. -ENOKEY is returned if a key could not be found. | |
1da177e4 | 1140 | */ |
237bbd29 | 1141 | struct key *find_keyring_by_name(const char *name, bool uid_keyring) |
1da177e4 | 1142 | { |
b206f281 | 1143 | struct user_namespace *ns = current_user_ns(); |
1da177e4 | 1144 | struct key *keyring; |
1da177e4 | 1145 | |
1da177e4 | 1146 | if (!name) |
cea7daa3 | 1147 | return ERR_PTR(-EINVAL); |
1da177e4 | 1148 | |
1da177e4 LT |
1149 | read_lock(&keyring_name_lock); |
1150 | ||
b206f281 DH |
1151 | /* Search this hash bucket for a keyring with a matching name that |
1152 | * grants Search permission and that hasn't been revoked | |
1153 | */ | |
1154 | list_for_each_entry(keyring, &ns->keyring_name_list, name_link) { | |
1155 | if (!kuid_has_mapping(ns, keyring->user->uid)) | |
1156 | continue; | |
1da177e4 | 1157 | |
b206f281 DH |
1158 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) |
1159 | continue; | |
1da177e4 | 1160 | |
b206f281 DH |
1161 | if (strcmp(keyring->description, name) != 0) |
1162 | continue; | |
1da177e4 | 1163 | |
b206f281 DH |
1164 | if (uid_keyring) { |
1165 | if (!test_bit(KEY_FLAG_UID_KEYRING, | |
1166 | &keyring->flags)) | |
1167 | continue; | |
1168 | } else { | |
1169 | if (key_permission(make_key_ref(keyring, 0), | |
028db3e2 | 1170 | KEY_NEED_SEARCH) < 0) |
cea7daa3 | 1171 | continue; |
1da177e4 | 1172 | } |
b206f281 DH |
1173 | |
1174 | /* we've got a match but we might end up racing with | |
1175 | * key_cleanup() if the keyring is currently 'dead' | |
1176 | * (ie. it has a zero usage count) */ | |
1177 | if (!refcount_inc_not_zero(&keyring->usage)) | |
1178 | continue; | |
1179 | keyring->last_used_at = ktime_get_real_seconds(); | |
1180 | goto out; | |
1da177e4 LT |
1181 | } |
1182 | ||
1da177e4 | 1183 | keyring = ERR_PTR(-ENOKEY); |
cea7daa3 TO |
1184 | out: |
1185 | read_unlock(&keyring_name_lock); | |
1da177e4 | 1186 | return keyring; |
a8b17ed0 | 1187 | } |
1da177e4 | 1188 | |
b2a4df20 DH |
1189 | static int keyring_detect_cycle_iterator(const void *object, |
1190 | void *iterator_data) | |
1191 | { | |
1192 | struct keyring_search_context *ctx = iterator_data; | |
1193 | const struct key *key = keyring_ptr_to_key(object); | |
1194 | ||
1195 | kenter("{%d}", key->serial); | |
1196 | ||
979e0d74 DH |
1197 | /* We might get a keyring with matching index-key that is nonetheless a |
1198 | * different keyring. */ | |
46291959 | 1199 | if (key != ctx->match_data.raw_data) |
979e0d74 DH |
1200 | return 0; |
1201 | ||
b2a4df20 DH |
1202 | ctx->result = ERR_PTR(-EDEADLK); |
1203 | return 1; | |
1204 | } | |
1205 | ||
1da177e4 | 1206 | /* |
328c95db | 1207 | * See if a cycle will be created by inserting acyclic tree B in acyclic |
973c9f4f DH |
1208 | * tree A at the topmost level (ie: as a direct child of A). |
1209 | * | |
1210 | * Since we are adding B to A at the top level, checking for cycles should just | |
1211 | * be a matter of seeing if node A is somewhere in tree B. | |
1da177e4 LT |
1212 | */ |
1213 | static int keyring_detect_cycle(struct key *A, struct key *B) | |
1214 | { | |
b2a4df20 | 1215 | struct keyring_search_context ctx = { |
46291959 DH |
1216 | .index_key = A->index_key, |
1217 | .match_data.raw_data = A, | |
1218 | .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
1219 | .iterator = keyring_detect_cycle_iterator, | |
1220 | .flags = (KEYRING_SEARCH_NO_STATE_CHECK | | |
1221 | KEYRING_SEARCH_NO_UPDATE_TIME | | |
1222 | KEYRING_SEARCH_NO_CHECK_PERM | | |
dcf49dbc DH |
1223 | KEYRING_SEARCH_DETECT_TOO_DEEP | |
1224 | KEYRING_SEARCH_RECURSE), | |
b2a4df20 | 1225 | }; |
1da177e4 | 1226 | |
76d8aeab | 1227 | rcu_read_lock(); |
b2a4df20 | 1228 | search_nested_keyrings(B, &ctx); |
76d8aeab | 1229 | rcu_read_unlock(); |
b2a4df20 | 1230 | return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result); |
f70e2e06 | 1231 | } |
cab8eb59 | 1232 | |
df593ee2 DH |
1233 | /* |
1234 | * Lock keyring for link. | |
1235 | */ | |
1236 | int __key_link_lock(struct key *keyring, | |
1237 | const struct keyring_index_key *index_key) | |
1238 | __acquires(&keyring->sem) | |
1239 | __acquires(&keyring_serialise_link_lock) | |
1240 | { | |
1241 | if (keyring->type != &key_type_keyring) | |
1242 | return -ENOTDIR; | |
1243 | ||
1244 | down_write(&keyring->sem); | |
1245 | ||
1246 | /* Serialise link/link calls to prevent parallel calls causing a cycle | |
1247 | * when linking two keyring in opposite orders. | |
1248 | */ | |
1249 | if (index_key->type == &key_type_keyring) | |
1250 | mutex_lock(&keyring_serialise_link_lock); | |
1251 | ||
1252 | return 0; | |
1253 | } | |
1254 | ||
ed0ac5c7 DH |
1255 | /* |
1256 | * Lock keyrings for move (link/unlink combination). | |
1257 | */ | |
1258 | int __key_move_lock(struct key *l_keyring, struct key *u_keyring, | |
1259 | const struct keyring_index_key *index_key) | |
1260 | __acquires(&l_keyring->sem) | |
1261 | __acquires(&u_keyring->sem) | |
1262 | __acquires(&keyring_serialise_link_lock) | |
1263 | { | |
1264 | if (l_keyring->type != &key_type_keyring || | |
1265 | u_keyring->type != &key_type_keyring) | |
1266 | return -ENOTDIR; | |
1267 | ||
1268 | /* We have to be very careful here to take the keyring locks in the | |
1269 | * right order, lest we open ourselves to deadlocking against another | |
1270 | * move operation. | |
1271 | */ | |
1272 | if (l_keyring < u_keyring) { | |
1273 | down_write(&l_keyring->sem); | |
1274 | down_write_nested(&u_keyring->sem, 1); | |
1275 | } else { | |
1276 | down_write(&u_keyring->sem); | |
1277 | down_write_nested(&l_keyring->sem, 1); | |
1278 | } | |
1279 | ||
1280 | /* Serialise link/link calls to prevent parallel calls causing a cycle | |
1281 | * when linking two keyring in opposite orders. | |
1282 | */ | |
1283 | if (index_key->type == &key_type_keyring) | |
1284 | mutex_lock(&keyring_serialise_link_lock); | |
1285 | ||
1286 | return 0; | |
1287 | } | |
1288 | ||
1da177e4 | 1289 | /* |
973c9f4f | 1290 | * Preallocate memory so that a key can be linked into to a keyring. |
1da177e4 | 1291 | */ |
b2a4df20 DH |
1292 | int __key_link_begin(struct key *keyring, |
1293 | const struct keyring_index_key *index_key, | |
1294 | struct assoc_array_edit **_edit) | |
1da177e4 | 1295 | { |
b2a4df20 DH |
1296 | struct assoc_array_edit *edit; |
1297 | int ret; | |
1da177e4 | 1298 | |
16feef43 | 1299 | kenter("%d,%s,%s,", |
b2a4df20 DH |
1300 | keyring->serial, index_key->type->name, index_key->description); |
1301 | ||
1302 | BUG_ON(index_key->desc_len == 0); | |
df593ee2 | 1303 | BUG_ON(*_edit != NULL); |
1da177e4 | 1304 | |
df593ee2 | 1305 | *_edit = NULL; |
f70e2e06 DH |
1306 | |
1307 | ret = -EKEYREVOKED; | |
1308 | if (test_bit(KEY_FLAG_REVOKED, &keyring->flags)) | |
df593ee2 | 1309 | goto error; |
553d603c | 1310 | |
b2a4df20 DH |
1311 | /* Create an edit script that will insert/replace the key in the |
1312 | * keyring tree. | |
1313 | */ | |
1314 | edit = assoc_array_insert(&keyring->keys, | |
1315 | &keyring_assoc_array_ops, | |
1316 | index_key, | |
1317 | NULL); | |
1318 | if (IS_ERR(edit)) { | |
1319 | ret = PTR_ERR(edit); | |
df593ee2 | 1320 | goto error; |
034faeb9 DH |
1321 | } |
1322 | ||
1323 | /* If we're not replacing a link in-place then we're going to need some | |
1324 | * extra quota. | |
1325 | */ | |
1326 | if (!edit->dead_leaf) { | |
1327 | ret = key_payload_reserve(keyring, | |
1328 | keyring->datalen + KEYQUOTA_LINK_BYTES); | |
1329 | if (ret < 0) | |
1330 | goto error_cancel; | |
1da177e4 LT |
1331 | } |
1332 | ||
b2a4df20 | 1333 | *_edit = edit; |
f70e2e06 DH |
1334 | kleave(" = 0"); |
1335 | return 0; | |
1da177e4 | 1336 | |
034faeb9 DH |
1337 | error_cancel: |
1338 | assoc_array_cancel_edit(edit); | |
df593ee2 | 1339 | error: |
f70e2e06 DH |
1340 | kleave(" = %d", ret); |
1341 | return ret; | |
1342 | } | |
1da177e4 | 1343 | |
f70e2e06 | 1344 | /* |
973c9f4f DH |
1345 | * Check already instantiated keys aren't going to be a problem. |
1346 | * | |
1347 | * The caller must have called __key_link_begin(). Don't need to call this for | |
1348 | * keys that were created since __key_link_begin() was called. | |
f70e2e06 DH |
1349 | */ |
1350 | int __key_link_check_live_key(struct key *keyring, struct key *key) | |
1351 | { | |
1352 | if (key->type == &key_type_keyring) | |
1353 | /* check that we aren't going to create a cycle by linking one | |
1354 | * keyring to another */ | |
1355 | return keyring_detect_cycle(keyring, key); | |
1356 | return 0; | |
1357 | } | |
1358 | ||
1359 | /* | |
973c9f4f DH |
1360 | * Link a key into to a keyring. |
1361 | * | |
1362 | * Must be called with __key_link_begin() having being called. Discards any | |
1363 | * already extant link to matching key if there is one, so that each keyring | |
1364 | * holds at most one link to any given key of a particular type+description | |
1365 | * combination. | |
f70e2e06 | 1366 | */ |
f7e47677 DH |
1367 | void __key_link(struct key *keyring, struct key *key, |
1368 | struct assoc_array_edit **_edit) | |
f70e2e06 | 1369 | { |
ccc3e6d9 | 1370 | __key_get(key); |
b2a4df20 DH |
1371 | assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key)); |
1372 | assoc_array_apply_edit(*_edit); | |
1373 | *_edit = NULL; | |
f7e47677 | 1374 | notify_key(keyring, NOTIFY_KEY_LINKED, key_serial(key)); |
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) | |
f7e47677 | 1458 | __key_link(keyring, 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); | |
f7e47677 | 1490 | |
eb0f68cb DH |
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); | |
f7e47677 | 1510 | notify_key(keyring, NOTIFY_KEY_UNLINKED, key_serial(key)); |
eb0f68cb DH |
1511 | *_edit = NULL; |
1512 | key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES); | |
1513 | } | |
1514 | ||
1515 | /* | |
1516 | * Finish unlinking a key from to a keyring. | |
1517 | */ | |
1518 | static void __key_unlink_end(struct key *keyring, | |
1519 | struct key *key, | |
1520 | struct assoc_array_edit *edit) | |
1521 | __releases(&keyring->sem) | |
1522 | { | |
1523 | if (edit) | |
1524 | assoc_array_cancel_edit(edit); | |
1525 | up_write(&keyring->sem); | |
1526 | } | |
1527 | ||
973c9f4f DH |
1528 | /** |
1529 | * key_unlink - Unlink the first link to a key from a keyring. | |
1530 | * @keyring: The keyring to remove the link from. | |
1531 | * @key: The key the link is to. | |
1532 | * | |
1533 | * Remove a link from a keyring to a key. | |
1534 | * | |
1535 | * This function will write-lock the keyring's semaphore. | |
1536 | * | |
1537 | * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if | |
1538 | * the key isn't linked to by the keyring or -ENOMEM if there's insufficient | |
1539 | * memory. | |
1540 | * | |
1541 | * It is assumed that the caller has checked that it is permitted for a link to | |
1542 | * be removed (the keyring should have Write permission; no permissions are | |
1543 | * required on the key). | |
1da177e4 LT |
1544 | */ |
1545 | int key_unlink(struct key *keyring, struct key *key) | |
1546 | { | |
eb0f68cb | 1547 | struct assoc_array_edit *edit = NULL; |
b2a4df20 | 1548 | int ret; |
1da177e4 LT |
1549 | |
1550 | key_check(keyring); | |
1551 | key_check(key); | |
1552 | ||
eb0f68cb DH |
1553 | ret = __key_unlink_lock(keyring); |
1554 | if (ret < 0) | |
1555 | return ret; | |
1da177e4 | 1556 | |
eb0f68cb DH |
1557 | ret = __key_unlink_begin(keyring, key, &edit); |
1558 | if (ret == 0) | |
1559 | __key_unlink(keyring, key, &edit); | |
1560 | __key_unlink_end(keyring, key, edit); | |
b2a4df20 | 1561 | return ret; |
a8b17ed0 | 1562 | } |
1da177e4 | 1563 | EXPORT_SYMBOL(key_unlink); |
1da177e4 | 1564 | |
ed0ac5c7 DH |
1565 | /** |
1566 | * key_move - Move a key from one keyring to another | |
1567 | * @key: The key to move | |
1568 | * @from_keyring: The keyring to remove the link from. | |
1569 | * @to_keyring: The keyring to make the link in. | |
1570 | * @flags: Qualifying flags, such as KEYCTL_MOVE_EXCL. | |
1571 | * | |
1572 | * Make a link in @to_keyring to a key, such that the keyring holds a reference | |
1573 | * on that key and the key can potentially be found by searching that keyring | |
1574 | * whilst simultaneously removing a link to the key from @from_keyring. | |
1575 | * | |
1576 | * This function will write-lock both keyring's semaphores and will consume | |
1577 | * some of the user's key data quota to hold the link on @to_keyring. | |
1578 | * | |
1579 | * Returns 0 if successful, -ENOTDIR if either keyring isn't a keyring, | |
1580 | * -EKEYREVOKED if either keyring has been revoked, -ENFILE if the second | |
1581 | * keyring is full, -EDQUOT if there is insufficient key data quota remaining | |
1582 | * to add another link or -ENOMEM if there's insufficient memory. If | |
1583 | * KEYCTL_MOVE_EXCL is set, then -EEXIST will be returned if there's already a | |
1584 | * matching key in @to_keyring. | |
1585 | * | |
1586 | * It is assumed that the caller has checked that it is permitted for a link to | |
1587 | * be made (the keyring should have Write permission and the key Link | |
1588 | * permission). | |
1589 | */ | |
1590 | int key_move(struct key *key, | |
1591 | struct key *from_keyring, | |
1592 | struct key *to_keyring, | |
1593 | unsigned int flags) | |
1594 | { | |
1595 | struct assoc_array_edit *from_edit = NULL, *to_edit = NULL; | |
1596 | int ret; | |
1597 | ||
1598 | kenter("%d,%d,%d", key->serial, from_keyring->serial, to_keyring->serial); | |
1599 | ||
1600 | if (from_keyring == to_keyring) | |
1601 | return 0; | |
1602 | ||
1603 | key_check(key); | |
1604 | key_check(from_keyring); | |
1605 | key_check(to_keyring); | |
1606 | ||
1607 | ret = __key_move_lock(from_keyring, to_keyring, &key->index_key); | |
1608 | if (ret < 0) | |
1609 | goto out; | |
1610 | ret = __key_unlink_begin(from_keyring, key, &from_edit); | |
1611 | if (ret < 0) | |
b2a4df20 | 1612 | goto error; |
ed0ac5c7 DH |
1613 | ret = __key_link_begin(to_keyring, &key->index_key, &to_edit); |
1614 | if (ret < 0) | |
b2a4df20 | 1615 | goto error; |
1da177e4 | 1616 | |
ed0ac5c7 DH |
1617 | ret = -EEXIST; |
1618 | if (to_edit->dead_leaf && (flags & KEYCTL_MOVE_EXCL)) | |
1619 | goto error; | |
1da177e4 | 1620 | |
ed0ac5c7 DH |
1621 | ret = __key_link_check_restriction(to_keyring, key); |
1622 | if (ret < 0) | |
1623 | goto error; | |
1624 | ret = __key_link_check_live_key(to_keyring, key); | |
1625 | if (ret < 0) | |
1626 | goto error; | |
1627 | ||
1628 | __key_unlink(from_keyring, key, &from_edit); | |
f7e47677 | 1629 | __key_link(to_keyring, key, &to_edit); |
76d8aeab | 1630 | error: |
ed0ac5c7 DH |
1631 | __key_link_end(to_keyring, &key->index_key, to_edit); |
1632 | __key_unlink_end(from_keyring, key, from_edit); | |
1633 | out: | |
1634 | kleave(" = %d", ret); | |
b2a4df20 | 1635 | return ret; |
a8b17ed0 | 1636 | } |
ed0ac5c7 | 1637 | EXPORT_SYMBOL(key_move); |
1da177e4 | 1638 | |
973c9f4f DH |
1639 | /** |
1640 | * keyring_clear - Clear a keyring | |
1641 | * @keyring: The keyring to clear. | |
1642 | * | |
1643 | * Clear the contents of the specified keyring. | |
1644 | * | |
1645 | * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring. | |
1da177e4 LT |
1646 | */ |
1647 | int keyring_clear(struct key *keyring) | |
1648 | { | |
b2a4df20 | 1649 | struct assoc_array_edit *edit; |
76d8aeab | 1650 | int ret; |
1da177e4 | 1651 | |
b2a4df20 DH |
1652 | if (keyring->type != &key_type_keyring) |
1653 | return -ENOTDIR; | |
1da177e4 | 1654 | |
b2a4df20 | 1655 | down_write(&keyring->sem); |
1da177e4 | 1656 | |
b2a4df20 DH |
1657 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1658 | if (IS_ERR(edit)) { | |
1659 | ret = PTR_ERR(edit); | |
1660 | } else { | |
1661 | if (edit) | |
1662 | assoc_array_apply_edit(edit); | |
f7e47677 | 1663 | notify_key(keyring, NOTIFY_KEY_CLEARED, 0); |
b2a4df20 | 1664 | key_payload_reserve(keyring, 0); |
1da177e4 LT |
1665 | ret = 0; |
1666 | } | |
1667 | ||
b2a4df20 | 1668 | up_write(&keyring->sem); |
1da177e4 | 1669 | return ret; |
a8b17ed0 | 1670 | } |
1da177e4 | 1671 | EXPORT_SYMBOL(keyring_clear); |
31204ed9 | 1672 | |
31204ed9 | 1673 | /* |
973c9f4f DH |
1674 | * Dispose of the links from a revoked keyring. |
1675 | * | |
1676 | * This is called with the key sem write-locked. | |
31204ed9 DH |
1677 | */ |
1678 | static void keyring_revoke(struct key *keyring) | |
1679 | { | |
b2a4df20 | 1680 | struct assoc_array_edit *edit; |
f0641cba | 1681 | |
b2a4df20 DH |
1682 | edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops); |
1683 | if (!IS_ERR(edit)) { | |
1684 | if (edit) | |
1685 | assoc_array_apply_edit(edit); | |
1686 | key_payload_reserve(keyring, 0); | |
1687 | } | |
1688 | } | |
31204ed9 | 1689 | |
62fe3182 | 1690 | static bool keyring_gc_select_iterator(void *object, void *iterator_data) |
b2a4df20 DH |
1691 | { |
1692 | struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1693 | time64_t *limit = iterator_data; |
31204ed9 | 1694 | |
b2a4df20 DH |
1695 | if (key_is_dead(key, *limit)) |
1696 | return false; | |
1697 | key_get(key); | |
1698 | return true; | |
a8b17ed0 | 1699 | } |
5d135440 | 1700 | |
62fe3182 DH |
1701 | static int keyring_gc_check_iterator(const void *object, void *iterator_data) |
1702 | { | |
1703 | const struct key *key = keyring_ptr_to_key(object); | |
074d5898 | 1704 | time64_t *limit = iterator_data; |
62fe3182 DH |
1705 | |
1706 | key_check(key); | |
1707 | return key_is_dead(key, *limit); | |
1708 | } | |
1709 | ||
5d135440 | 1710 | /* |
62fe3182 | 1711 | * Garbage collect pointers from a keyring. |
973c9f4f | 1712 | * |
62fe3182 DH |
1713 | * Not called with any locks held. The keyring's key struct will not be |
1714 | * deallocated under us as only our caller may deallocate it. | |
5d135440 | 1715 | */ |
074d5898 | 1716 | void keyring_gc(struct key *keyring, time64_t limit) |
5d135440 | 1717 | { |
62fe3182 DH |
1718 | int result; |
1719 | ||
1720 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
5d135440 | 1721 | |
62fe3182 DH |
1722 | if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) | |
1723 | (1 << KEY_FLAG_REVOKED))) | |
1724 | goto dont_gc; | |
1725 | ||
1726 | /* scan the keyring looking for dead keys */ | |
1727 | rcu_read_lock(); | |
1728 | result = assoc_array_iterate(&keyring->keys, | |
1729 | keyring_gc_check_iterator, &limit); | |
1730 | rcu_read_unlock(); | |
1731 | if (result == true) | |
1732 | goto do_gc; | |
1733 | ||
1734 | dont_gc: | |
1735 | kleave(" [no gc]"); | |
1736 | return; | |
1737 | ||
1738 | do_gc: | |
5d135440 | 1739 | down_write(&keyring->sem); |
b2a4df20 | 1740 | assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops, |
62fe3182 | 1741 | keyring_gc_select_iterator, &limit); |
c08ef808 | 1742 | up_write(&keyring->sem); |
62fe3182 | 1743 | kleave(" [gc]"); |
5d135440 | 1744 | } |
2b6aa412 MM |
1745 | |
1746 | /* | |
1747 | * Garbage collect restriction pointers from a keyring. | |
1748 | * | |
1749 | * Keyring restrictions are associated with a key type, and must be cleaned | |
1750 | * up if the key type is unregistered. The restriction is altered to always | |
1751 | * reject additional keys so a keyring cannot be opened up by unregistering | |
1752 | * a key type. | |
1753 | * | |
1754 | * Not called with any keyring locks held. The keyring's key struct will not | |
1755 | * be deallocated under us as only our caller may deallocate it. | |
1756 | * | |
1757 | * The caller is required to hold key_types_sem and dead_type->sem. This is | |
1758 | * fulfilled by key_gc_keytype() holding the locks on behalf of | |
1759 | * key_garbage_collector(), which it invokes on a workqueue. | |
1760 | */ | |
1761 | void keyring_restriction_gc(struct key *keyring, struct key_type *dead_type) | |
1762 | { | |
1763 | struct key_restriction *keyres; | |
1764 | ||
1765 | kenter("%x{%s}", keyring->serial, keyring->description ?: ""); | |
1766 | ||
1767 | /* | |
1768 | * keyring->restrict_link is only assigned at key allocation time | |
1769 | * or with the key type locked, so the only values that could be | |
1770 | * concurrently assigned to keyring->restrict_link are for key | |
1771 | * types other than dead_type. Given this, it's ok to check | |
1772 | * the key type before acquiring keyring->sem. | |
1773 | */ | |
1774 | if (!dead_type || !keyring->restrict_link || | |
1775 | keyring->restrict_link->keytype != dead_type) { | |
1776 | kleave(" [no restriction gc]"); | |
1777 | return; | |
1778 | } | |
1779 | ||
1780 | /* Lock the keyring to ensure that a link is not in progress */ | |
1781 | down_write(&keyring->sem); | |
1782 | ||
1783 | keyres = keyring->restrict_link; | |
1784 | ||
1785 | keyres->check = restrict_link_reject; | |
1786 | ||
1787 | key_put(keyres->key); | |
1788 | keyres->key = NULL; | |
1789 | keyres->keytype = NULL; | |
1790 | ||
1791 | up_write(&keyring->sem); | |
1792 | ||
1793 | kleave(" [restriction gc]"); | |
1794 | } |