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David Howells69664cf2008-04-29 01:01:31 -07001/* Keyring handling
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 *
David Howellsb2a4df22013-09-24 10:35:18 +01003 * Copyright (C) 2004-2005, 2008, 2013 Red Hat, Inc. All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/sched.h>
15#include <linux/slab.h>
David Howells29db9192005-10-30 15:02:44 -080016#include <linux/security.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/seq_file.h>
18#include <linux/err.h>
David Howellse9e349b2008-11-14 10:39:13 +110019#include <keys/keyring-type.h>
David Howellsb2a4df22013-09-24 10:35:18 +010020#include <keys/user-type.h>
21#include <linux/assoc_array_priv.h>
Chihau Chau512ea3b2010-03-08 20:11:34 -030022#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include "internal.h"
24
25/*
David Howells973c9f42011-01-20 16:38:33 +000026 * When plumbing the depths of the key tree, this sets a hard limit
27 * set on how deep we're willing to go.
Linus Torvalds1da177e2005-04-16 15:20:36 -070028 */
29#define KEYRING_SEARCH_MAX_DEPTH 6
30
31/*
David Howells973c9f42011-01-20 16:38:33 +000032 * We keep all named keyrings in a hash to speed looking them up.
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 */
34#define KEYRING_NAME_HASH_SIZE (1 << 5)
35
David Howellsb2a4df22013-09-24 10:35:18 +010036/*
37 * We mark pointers we pass to the associative array with bit 1 set if
38 * they're keyrings and clear otherwise.
39 */
40#define KEYRING_PTR_SUBTYPE 0x2UL
41
42static inline bool keyring_ptr_is_keyring(const struct assoc_array_ptr *x)
43{
44 return (unsigned long)x & KEYRING_PTR_SUBTYPE;
45}
46static inline struct key *keyring_ptr_to_key(const struct assoc_array_ptr *x)
47{
48 void *object = assoc_array_ptr_to_leaf(x);
49 return (struct key *)((unsigned long)object & ~KEYRING_PTR_SUBTYPE);
50}
51static inline void *keyring_key_to_ptr(struct key *key)
52{
53 if (key->type == &key_type_keyring)
54 return (void *)((unsigned long)key | KEYRING_PTR_SUBTYPE);
55 return key;
56}
57
Linus Torvalds1da177e2005-04-16 15:20:36 -070058static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE];
59static DEFINE_RWLOCK(keyring_name_lock);
60
61static inline unsigned keyring_hash(const char *desc)
62{
63 unsigned bucket = 0;
64
65 for (; *desc; desc++)
Justin P. Mattockc5b60b52010-04-21 00:02:11 -070066 bucket += (unsigned char)*desc;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68 return bucket & (KEYRING_NAME_HASH_SIZE - 1);
69}
70
71/*
David Howells973c9f42011-01-20 16:38:33 +000072 * The keyring key type definition. Keyrings are simply keys of this type and
73 * can be treated as ordinary keys in addition to having their own special
74 * operations.
Linus Torvalds1da177e2005-04-16 15:20:36 -070075 */
David Howells5d19e202014-07-18 18:56:36 +010076static int keyring_preparse(struct key_preparsed_payload *prep);
77static void keyring_free_preparse(struct key_preparsed_payload *prep);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078static int keyring_instantiate(struct key *keyring,
David Howellscf7f6012012-09-13 13:06:29 +010079 struct key_preparsed_payload *prep);
David Howells31204ed2006-06-26 00:24:51 -070080static void keyring_revoke(struct key *keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081static void keyring_destroy(struct key *keyring);
82static void keyring_describe(const struct key *keyring, struct seq_file *m);
83static long keyring_read(const struct key *keyring,
84 char __user *buffer, size_t buflen);
85
86struct key_type key_type_keyring = {
87 .name = "keyring",
David Howellsb2a4df22013-09-24 10:35:18 +010088 .def_datalen = 0,
David Howells5d19e202014-07-18 18:56:36 +010089 .preparse = keyring_preparse,
90 .free_preparse = keyring_free_preparse,
Linus Torvalds1da177e2005-04-16 15:20:36 -070091 .instantiate = keyring_instantiate,
David Howells31204ed2006-06-26 00:24:51 -070092 .revoke = keyring_revoke,
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 .destroy = keyring_destroy,
94 .describe = keyring_describe,
95 .read = keyring_read,
96};
David Howells73182262007-04-26 15:46:23 -070097EXPORT_SYMBOL(key_type_keyring);
98
Linus Torvalds1da177e2005-04-16 15:20:36 -070099/*
David Howells973c9f42011-01-20 16:38:33 +0000100 * Semaphore to serialise link/link calls to prevent two link calls in parallel
101 * introducing a cycle.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 */
Adrian Bunk1ae8f402006-01-06 00:11:25 -0800103static DECLARE_RWSEM(keyring_serialise_link_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105/*
David Howells973c9f42011-01-20 16:38:33 +0000106 * Publish the name of a keyring so that it can be found by name (if it has
107 * one).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 */
David Howells69664cf2008-04-29 01:01:31 -0700109static void keyring_publish_name(struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110{
111 int bucket;
112
113 if (keyring->description) {
114 bucket = keyring_hash(keyring->description);
115
116 write_lock(&keyring_name_lock);
117
118 if (!keyring_name_hash[bucket].next)
119 INIT_LIST_HEAD(&keyring_name_hash[bucket]);
120
121 list_add_tail(&keyring->type_data.link,
122 &keyring_name_hash[bucket]);
123
124 write_unlock(&keyring_name_lock);
125 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000126}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128/*
David Howells5d19e202014-07-18 18:56:36 +0100129 * Preparse a keyring payload
130 */
131static int keyring_preparse(struct key_preparsed_payload *prep)
132{
133 return prep->datalen != 0 ? -EINVAL : 0;
134}
135
136/*
137 * Free a preparse of a user defined key payload
138 */
139static void keyring_free_preparse(struct key_preparsed_payload *prep)
140{
141}
142
143/*
David Howells973c9f42011-01-20 16:38:33 +0000144 * Initialise a keyring.
145 *
146 * Returns 0 on success, -EINVAL if given any data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 */
148static int keyring_instantiate(struct key *keyring,
David Howellscf7f6012012-09-13 13:06:29 +0100149 struct key_preparsed_payload *prep)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
David Howells5d19e202014-07-18 18:56:36 +0100151 assoc_array_init(&keyring->keys);
152 /* make the keyring available by name if it has one */
153 keyring_publish_name(keyring);
154 return 0;
David Howellsa8b17ed2011-01-20 16:38:27 +0000155}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157/*
David Howellsb2a4df22013-09-24 10:35:18 +0100158 * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd
159 * fold the carry back too, but that requires inline asm.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 */
David Howellsb2a4df22013-09-24 10:35:18 +0100161static u64 mult_64x32_and_fold(u64 x, u32 y)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162{
David Howellsb2a4df22013-09-24 10:35:18 +0100163 u64 hi = (u64)(u32)(x >> 32) * y;
164 u64 lo = (u64)(u32)(x) * y;
165 return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32);
David Howellsa8b17ed2011-01-20 16:38:27 +0000166}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168/*
David Howellsb2a4df22013-09-24 10:35:18 +0100169 * Hash a key type and description.
170 */
171static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key)
172{
173 const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP;
David Howellsd54e58b2013-12-02 11:24:18 +0000174 const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK;
David Howellsb2a4df22013-09-24 10:35:18 +0100175 const char *description = index_key->description;
176 unsigned long hash, type;
177 u32 piece;
178 u64 acc;
179 int n, desc_len = index_key->desc_len;
180
181 type = (unsigned long)index_key->type;
182
183 acc = mult_64x32_and_fold(type, desc_len + 13);
184 acc = mult_64x32_and_fold(acc, 9207);
185 for (;;) {
186 n = desc_len;
187 if (n <= 0)
188 break;
189 if (n > 4)
190 n = 4;
191 piece = 0;
192 memcpy(&piece, description, n);
193 description += n;
194 desc_len -= n;
195 acc = mult_64x32_and_fold(acc, piece);
196 acc = mult_64x32_and_fold(acc, 9207);
197 }
198
199 /* Fold the hash down to 32 bits if need be. */
200 hash = acc;
201 if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32)
202 hash ^= acc >> 32;
203
204 /* Squidge all the keyrings into a separate part of the tree to
205 * ordinary keys by making sure the lowest level segment in the hash is
206 * zero for keyrings and non-zero otherwise.
207 */
David Howellsd54e58b2013-12-02 11:24:18 +0000208 if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100209 return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1;
David Howellsd54e58b2013-12-02 11:24:18 +0000210 if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0)
211 return (hash + (hash << level_shift)) & ~fan_mask;
David Howellsb2a4df22013-09-24 10:35:18 +0100212 return hash;
213}
214
215/*
216 * Build the next index key chunk.
217 *
218 * On 32-bit systems the index key is laid out as:
219 *
220 * 0 4 5 9...
221 * hash desclen typeptr desc[]
222 *
223 * On 64-bit systems:
224 *
225 * 0 8 9 17...
226 * hash desclen typeptr desc[]
227 *
228 * We return it one word-sized chunk at a time.
229 */
230static unsigned long keyring_get_key_chunk(const void *data, int level)
231{
232 const struct keyring_index_key *index_key = data;
233 unsigned long chunk = 0;
234 long offset = 0;
235 int desc_len = index_key->desc_len, n = sizeof(chunk);
236
237 level /= ASSOC_ARRAY_KEY_CHUNK_SIZE;
238 switch (level) {
239 case 0:
240 return hash_key_type_and_desc(index_key);
241 case 1:
242 return ((unsigned long)index_key->type << 8) | desc_len;
243 case 2:
244 if (desc_len == 0)
245 return (u8)((unsigned long)index_key->type >>
246 (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
247 n--;
248 offset = 1;
249 default:
250 offset += sizeof(chunk) - 1;
251 offset += (level - 3) * sizeof(chunk);
252 if (offset >= desc_len)
253 return 0;
254 desc_len -= offset;
255 if (desc_len > n)
256 desc_len = n;
257 offset += desc_len;
258 do {
259 chunk <<= 8;
260 chunk |= ((u8*)index_key->description)[--offset];
261 } while (--desc_len > 0);
262
263 if (level == 2) {
264 chunk <<= 8;
265 chunk |= (u8)((unsigned long)index_key->type >>
266 (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
267 }
268 return chunk;
269 }
270}
271
272static unsigned long keyring_get_object_key_chunk(const void *object, int level)
273{
274 const struct key *key = keyring_ptr_to_key(object);
275 return keyring_get_key_chunk(&key->index_key, level);
276}
277
278static bool keyring_compare_object(const void *object, const void *data)
279{
280 const struct keyring_index_key *index_key = data;
281 const struct key *key = keyring_ptr_to_key(object);
282
283 return key->index_key.type == index_key->type &&
284 key->index_key.desc_len == index_key->desc_len &&
285 memcmp(key->index_key.description, index_key->description,
286 index_key->desc_len) == 0;
287}
288
289/*
290 * Compare the index keys of a pair of objects and determine the bit position
291 * at which they differ - if they differ.
292 */
David Howells23fd78d2013-12-02 11:24:18 +0000293static int keyring_diff_objects(const void *object, const void *data)
David Howellsb2a4df22013-09-24 10:35:18 +0100294{
David Howells23fd78d2013-12-02 11:24:18 +0000295 const struct key *key_a = keyring_ptr_to_key(object);
David Howellsb2a4df22013-09-24 10:35:18 +0100296 const struct keyring_index_key *a = &key_a->index_key;
David Howells23fd78d2013-12-02 11:24:18 +0000297 const struct keyring_index_key *b = data;
David Howellsb2a4df22013-09-24 10:35:18 +0100298 unsigned long seg_a, seg_b;
299 int level, i;
300
301 level = 0;
302 seg_a = hash_key_type_and_desc(a);
303 seg_b = hash_key_type_and_desc(b);
304 if ((seg_a ^ seg_b) != 0)
305 goto differ;
306
307 /* The number of bits contributed by the hash is controlled by a
308 * constant in the assoc_array headers. Everything else thereafter we
309 * can deal with as being machine word-size dependent.
310 */
311 level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8;
312 seg_a = a->desc_len;
313 seg_b = b->desc_len;
314 if ((seg_a ^ seg_b) != 0)
315 goto differ;
316
317 /* The next bit may not work on big endian */
318 level++;
319 seg_a = (unsigned long)a->type;
320 seg_b = (unsigned long)b->type;
321 if ((seg_a ^ seg_b) != 0)
322 goto differ;
323
324 level += sizeof(unsigned long);
325 if (a->desc_len == 0)
326 goto same;
327
328 i = 0;
329 if (((unsigned long)a->description | (unsigned long)b->description) &
330 (sizeof(unsigned long) - 1)) {
331 do {
332 seg_a = *(unsigned long *)(a->description + i);
333 seg_b = *(unsigned long *)(b->description + i);
334 if ((seg_a ^ seg_b) != 0)
335 goto differ_plus_i;
336 i += sizeof(unsigned long);
337 } while (i < (a->desc_len & (sizeof(unsigned long) - 1)));
338 }
339
340 for (; i < a->desc_len; i++) {
341 seg_a = *(unsigned char *)(a->description + i);
342 seg_b = *(unsigned char *)(b->description + i);
343 if ((seg_a ^ seg_b) != 0)
344 goto differ_plus_i;
345 }
346
347same:
348 return -1;
349
350differ_plus_i:
351 level += i;
352differ:
353 i = level * 8 + __ffs(seg_a ^ seg_b);
354 return i;
355}
356
357/*
358 * Free an object after stripping the keyring flag off of the pointer.
359 */
360static void keyring_free_object(void *object)
361{
362 key_put(keyring_ptr_to_key(object));
363}
364
365/*
366 * Operations for keyring management by the index-tree routines.
367 */
368static const struct assoc_array_ops keyring_assoc_array_ops = {
369 .get_key_chunk = keyring_get_key_chunk,
370 .get_object_key_chunk = keyring_get_object_key_chunk,
371 .compare_object = keyring_compare_object,
372 .diff_objects = keyring_diff_objects,
373 .free_object = keyring_free_object,
374};
375
376/*
David Howells973c9f42011-01-20 16:38:33 +0000377 * Clean up a keyring when it is destroyed. Unpublish its name if it had one
378 * and dispose of its data.
David Howells233e4732012-05-11 10:56:56 +0100379 *
380 * The garbage collector detects the final key_put(), removes the keyring from
381 * the serial number tree and then does RCU synchronisation before coming here,
382 * so we shouldn't need to worry about code poking around here with the RCU
383 * readlock held by this time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 */
385static void keyring_destroy(struct key *keyring)
386{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 if (keyring->description) {
388 write_lock(&keyring_name_lock);
David Howells94efe722005-08-04 13:07:07 -0700389
390 if (keyring->type_data.link.next != NULL &&
391 !list_empty(&keyring->type_data.link))
392 list_del(&keyring->type_data.link);
393
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 write_unlock(&keyring_name_lock);
395 }
396
David Howellsb2a4df22013-09-24 10:35:18 +0100397 assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops);
David Howellsa8b17ed2011-01-20 16:38:27 +0000398}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400/*
David Howells973c9f42011-01-20 16:38:33 +0000401 * Describe a keyring for /proc.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 */
403static void keyring_describe(const struct key *keyring, struct seq_file *m)
404{
wzt.wzt@gmail.comc8563472010-03-04 21:26:23 +0800405 if (keyring->description)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 seq_puts(m, keyring->description);
wzt.wzt@gmail.comc8563472010-03-04 21:26:23 +0800407 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 seq_puts(m, "[anon]");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
David Howells78b72802011-03-11 17:57:23 +0000410 if (key_is_instantiated(keyring)) {
David Howellsb2a4df22013-09-24 10:35:18 +0100411 if (keyring->keys.nr_leaves_on_tree != 0)
412 seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree);
David Howells78b72802011-03-11 17:57:23 +0000413 else
414 seq_puts(m, ": empty");
David Howells78b72802011-03-11 17:57:23 +0000415 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000416}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417
David Howellsb2a4df22013-09-24 10:35:18 +0100418struct keyring_read_iterator_context {
419 size_t qty;
420 size_t count;
421 key_serial_t __user *buffer;
422};
423
424static int keyring_read_iterator(const void *object, void *data)
425{
426 struct keyring_read_iterator_context *ctx = data;
427 const struct key *key = keyring_ptr_to_key(object);
428 int ret;
429
430 kenter("{%s,%d},,{%zu/%zu}",
431 key->type->name, key->serial, ctx->count, ctx->qty);
432
433 if (ctx->count >= ctx->qty)
434 return 1;
435
436 ret = put_user(key->serial, ctx->buffer);
437 if (ret < 0)
438 return ret;
439 ctx->buffer++;
440 ctx->count += sizeof(key->serial);
441 return 0;
442}
443
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444/*
David Howells973c9f42011-01-20 16:38:33 +0000445 * Read a list of key IDs from the keyring's contents in binary form
446 *
David Howellsb2a4df22013-09-24 10:35:18 +0100447 * The keyring's semaphore is read-locked by the caller. This prevents someone
448 * from modifying it under us - which could cause us to read key IDs multiple
449 * times.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 */
451static long keyring_read(const struct key *keyring,
452 char __user *buffer, size_t buflen)
453{
David Howellsb2a4df22013-09-24 10:35:18 +0100454 struct keyring_read_iterator_context ctx;
455 unsigned long nr_keys;
456 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457
David Howellsb2a4df22013-09-24 10:35:18 +0100458 kenter("{%d},,%zu", key_serial(keyring), buflen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459
David Howellsb2a4df22013-09-24 10:35:18 +0100460 if (buflen & (sizeof(key_serial_t) - 1))
461 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462
David Howellsb2a4df22013-09-24 10:35:18 +0100463 nr_keys = keyring->keys.nr_leaves_on_tree;
464 if (nr_keys == 0)
465 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466
David Howellsb2a4df22013-09-24 10:35:18 +0100467 /* Calculate how much data we could return */
468 ctx.qty = nr_keys * sizeof(key_serial_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
David Howellsb2a4df22013-09-24 10:35:18 +0100470 if (!buffer || !buflen)
471 return ctx.qty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472
David Howellsb2a4df22013-09-24 10:35:18 +0100473 if (buflen > ctx.qty)
474 ctx.qty = buflen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
David Howellsb2a4df22013-09-24 10:35:18 +0100476 /* Copy the IDs of the subscribed keys into the buffer */
477 ctx.buffer = (key_serial_t __user *)buffer;
478 ctx.count = 0;
479 ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx);
480 if (ret < 0) {
481 kleave(" = %d [iterate]", ret);
482 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 }
484
David Howellsb2a4df22013-09-24 10:35:18 +0100485 kleave(" = %zu [ok]", ctx.count);
486 return ctx.count;
David Howellsa8b17ed2011-01-20 16:38:27 +0000487}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489/*
David Howells973c9f42011-01-20 16:38:33 +0000490 * Allocate a keyring and link into the destination keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800492struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
David Howells96b5c8f2012-10-02 19:24:56 +0100493 const struct cred *cred, key_perm_t perm,
494 unsigned long flags, struct key *dest)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
496 struct key *keyring;
497 int ret;
498
499 keyring = key_alloc(&key_type_keyring, description,
David Howells96b5c8f2012-10-02 19:24:56 +0100500 uid, gid, cred, perm, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 if (!IS_ERR(keyring)) {
David Howells3e301482005-06-23 22:00:56 -0700502 ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (ret < 0) {
504 key_put(keyring);
505 keyring = ERR_PTR(ret);
506 }
507 }
508
509 return keyring;
David Howellsa8b17ed2011-01-20 16:38:27 +0000510}
David Howellsf8aa23a2012-10-02 19:24:56 +0100511EXPORT_SYMBOL(keyring_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
David Howellsb2a4df22013-09-24 10:35:18 +0100513/*
David Howellsc06cfb02014-09-16 17:36:06 +0100514 * By default, we keys found by getting an exact match on their descriptions.
515 */
David Howells0c903ab2014-09-16 17:36:08 +0100516bool key_default_cmp(const struct key *key,
517 const struct key_match_data *match_data)
David Howellsc06cfb02014-09-16 17:36:06 +0100518{
519 return strcmp(key->description, match_data->raw_data) == 0;
520}
521
522/*
David Howellsb2a4df22013-09-24 10:35:18 +0100523 * Iteration function to consider each key found.
524 */
525static int keyring_search_iterator(const void *object, void *iterator_data)
526{
527 struct keyring_search_context *ctx = iterator_data;
528 const struct key *key = keyring_ptr_to_key(object);
529 unsigned long kflags = key->flags;
530
531 kenter("{%d}", key->serial);
532
533 /* ignore keys not of this type */
534 if (key->type != ctx->index_key.type) {
535 kleave(" = 0 [!type]");
536 return 0;
537 }
538
539 /* skip invalidated, revoked and expired keys */
540 if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
541 if (kflags & ((1 << KEY_FLAG_INVALIDATED) |
542 (1 << KEY_FLAG_REVOKED))) {
543 ctx->result = ERR_PTR(-EKEYREVOKED);
544 kleave(" = %d [invrev]", ctx->skipped_ret);
545 goto skipped;
546 }
547
548 if (key->expiry && ctx->now.tv_sec >= key->expiry) {
David Howells0b0a8412014-12-01 22:52:53 +0000549 if (!(ctx->flags & KEYRING_SEARCH_SKIP_EXPIRED))
550 ctx->result = ERR_PTR(-EKEYEXPIRED);
David Howellsb2a4df22013-09-24 10:35:18 +0100551 kleave(" = %d [expire]", ctx->skipped_ret);
552 goto skipped;
553 }
554 }
555
556 /* keys that don't match */
David Howells46291952014-09-16 17:36:02 +0100557 if (!ctx->match_data.cmp(key, &ctx->match_data)) {
David Howellsb2a4df22013-09-24 10:35:18 +0100558 kleave(" = 0 [!match]");
559 return 0;
560 }
561
562 /* key must have search permissions */
563 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
564 key_task_permission(make_key_ref(key, ctx->possessed),
David Howellsf5895942014-03-14 17:44:49 +0000565 ctx->cred, KEY_NEED_SEARCH) < 0) {
David Howellsb2a4df22013-09-24 10:35:18 +0100566 ctx->result = ERR_PTR(-EACCES);
567 kleave(" = %d [!perm]", ctx->skipped_ret);
568 goto skipped;
569 }
570
571 if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
572 /* we set a different error code if we pass a negative key */
573 if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
David Howells74792b02013-10-30 11:15:24 +0000574 smp_rmb();
David Howellsb2a4df22013-09-24 10:35:18 +0100575 ctx->result = ERR_PTR(key->type_data.reject_error);
576 kleave(" = %d [neg]", ctx->skipped_ret);
577 goto skipped;
578 }
579 }
580
581 /* Found */
582 ctx->result = make_key_ref(key, ctx->possessed);
583 kleave(" = 1 [found]");
584 return 1;
585
586skipped:
587 return ctx->skipped_ret;
588}
589
590/*
591 * Search inside a keyring for a key. We can search by walking to it
592 * directly based on its index-key or we can iterate over the entire
593 * tree looking for it, based on the match function.
594 */
595static int search_keyring(struct key *keyring, struct keyring_search_context *ctx)
596{
David Howells46291952014-09-16 17:36:02 +0100597 if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) {
David Howellsb2a4df22013-09-24 10:35:18 +0100598 const void *object;
599
600 object = assoc_array_find(&keyring->keys,
601 &keyring_assoc_array_ops,
602 &ctx->index_key);
603 return object ? ctx->iterator(object, ctx) : 0;
604 }
605 return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx);
606}
607
608/*
609 * Search a tree of keyrings that point to other keyrings up to the maximum
610 * depth.
611 */
612static bool search_nested_keyrings(struct key *keyring,
613 struct keyring_search_context *ctx)
614{
615 struct {
616 struct key *keyring;
617 struct assoc_array_node *node;
618 int slot;
619 } stack[KEYRING_SEARCH_MAX_DEPTH];
620
621 struct assoc_array_shortcut *shortcut;
622 struct assoc_array_node *node;
623 struct assoc_array_ptr *ptr;
624 struct key *key;
625 int sp = 0, slot;
626
627 kenter("{%d},{%s,%s}",
628 keyring->serial,
629 ctx->index_key.type->name,
630 ctx->index_key.description);
631
David Howells054f6182014-12-01 22:52:50 +0000632#define STATE_CHECKS (KEYRING_SEARCH_NO_STATE_CHECK | KEYRING_SEARCH_DO_STATE_CHECK)
633 BUG_ON((ctx->flags & STATE_CHECKS) == 0 ||
634 (ctx->flags & STATE_CHECKS) == STATE_CHECKS);
635
David Howellsb2a4df22013-09-24 10:35:18 +0100636 if (ctx->index_key.description)
637 ctx->index_key.desc_len = strlen(ctx->index_key.description);
638
639 /* Check to see if this top-level keyring is what we are looking for
640 * and whether it is valid or not.
641 */
David Howells46291952014-09-16 17:36:02 +0100642 if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE ||
David Howellsb2a4df22013-09-24 10:35:18 +0100643 keyring_compare_object(keyring, &ctx->index_key)) {
644 ctx->skipped_ret = 2;
David Howellsb2a4df22013-09-24 10:35:18 +0100645 switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) {
646 case 1:
647 goto found;
648 case 2:
649 return false;
650 default:
651 break;
652 }
653 }
654
655 ctx->skipped_ret = 0;
David Howellsb2a4df22013-09-24 10:35:18 +0100656
657 /* Start processing a new keyring */
658descend_to_keyring:
659 kdebug("descend to %d", keyring->serial);
660 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
661 (1 << KEY_FLAG_REVOKED)))
662 goto not_this_keyring;
663
664 /* Search through the keys in this keyring before its searching its
665 * subtrees.
666 */
667 if (search_keyring(keyring, ctx))
668 goto found;
669
670 /* Then manually iterate through the keyrings nested in this one.
671 *
672 * Start from the root node of the index tree. Because of the way the
673 * hash function has been set up, keyrings cluster on the leftmost
674 * branch of the root node (root slot 0) or in the root node itself.
675 * Non-keyrings avoid the leftmost branch of the root entirely (root
676 * slots 1-15).
677 */
678 ptr = ACCESS_ONCE(keyring->keys.root);
679 if (!ptr)
680 goto not_this_keyring;
681
682 if (assoc_array_ptr_is_shortcut(ptr)) {
683 /* If the root is a shortcut, either the keyring only contains
684 * keyring pointers (everything clusters behind root slot 0) or
685 * doesn't contain any keyring pointers.
686 */
687 shortcut = assoc_array_ptr_to_shortcut(ptr);
688 smp_read_barrier_depends();
689 if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
690 goto not_this_keyring;
691
692 ptr = ACCESS_ONCE(shortcut->next_node);
693 node = assoc_array_ptr_to_node(ptr);
694 goto begin_node;
695 }
696
697 node = assoc_array_ptr_to_node(ptr);
698 smp_read_barrier_depends();
699
700 ptr = node->slots[0];
701 if (!assoc_array_ptr_is_meta(ptr))
702 goto begin_node;
703
704descend_to_node:
705 /* Descend to a more distal node in this keyring's content tree and go
706 * through that.
707 */
708 kdebug("descend");
709 if (assoc_array_ptr_is_shortcut(ptr)) {
710 shortcut = assoc_array_ptr_to_shortcut(ptr);
711 smp_read_barrier_depends();
712 ptr = ACCESS_ONCE(shortcut->next_node);
713 BUG_ON(!assoc_array_ptr_is_node(ptr));
David Howellsb2a4df22013-09-24 10:35:18 +0100714 }
David Howells9c5e45d2013-12-02 11:24:19 +0000715 node = assoc_array_ptr_to_node(ptr);
David Howellsb2a4df22013-09-24 10:35:18 +0100716
717begin_node:
718 kdebug("begin_node");
719 smp_read_barrier_depends();
720 slot = 0;
721ascend_to_node:
722 /* Go through the slots in a node */
723 for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
724 ptr = ACCESS_ONCE(node->slots[slot]);
725
726 if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)
727 goto descend_to_node;
728
729 if (!keyring_ptr_is_keyring(ptr))
730 continue;
731
732 key = keyring_ptr_to_key(ptr);
733
734 if (sp >= KEYRING_SEARCH_MAX_DEPTH) {
735 if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) {
736 ctx->result = ERR_PTR(-ELOOP);
737 return false;
738 }
739 goto not_this_keyring;
740 }
741
742 /* Search a nested keyring */
743 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
744 key_task_permission(make_key_ref(key, ctx->possessed),
David Howellsf5895942014-03-14 17:44:49 +0000745 ctx->cred, KEY_NEED_SEARCH) < 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100746 continue;
747
748 /* stack the current position */
749 stack[sp].keyring = keyring;
750 stack[sp].node = node;
751 stack[sp].slot = slot;
752 sp++;
753
754 /* begin again with the new keyring */
755 keyring = key;
756 goto descend_to_keyring;
757 }
758
759 /* We've dealt with all the slots in the current node, so now we need
760 * to ascend to the parent and continue processing there.
761 */
762 ptr = ACCESS_ONCE(node->back_pointer);
763 slot = node->parent_slot;
764
765 if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
766 shortcut = assoc_array_ptr_to_shortcut(ptr);
767 smp_read_barrier_depends();
768 ptr = ACCESS_ONCE(shortcut->back_pointer);
769 slot = shortcut->parent_slot;
770 }
771 if (!ptr)
772 goto not_this_keyring;
773 node = assoc_array_ptr_to_node(ptr);
774 smp_read_barrier_depends();
775 slot++;
776
777 /* If we've ascended to the root (zero backpointer), we must have just
778 * finished processing the leftmost branch rather than the root slots -
779 * so there can't be any more keyrings for us to find.
780 */
781 if (node->back_pointer) {
782 kdebug("ascend %d", slot);
783 goto ascend_to_node;
784 }
785
786 /* The keyring we're looking at was disqualified or didn't contain a
787 * matching key.
788 */
789not_this_keyring:
790 kdebug("not_this_keyring %d", sp);
791 if (sp <= 0) {
792 kleave(" = false");
793 return false;
794 }
795
796 /* Resume the processing of a keyring higher up in the tree */
797 sp--;
798 keyring = stack[sp].keyring;
799 node = stack[sp].node;
800 slot = stack[sp].slot + 1;
801 kdebug("ascend to %d [%d]", keyring->serial, slot);
802 goto ascend_to_node;
803
804 /* We found a viable match */
805found:
806 key = key_ref_to_ptr(ctx->result);
807 key_check(key);
808 if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) {
809 key->last_used_at = ctx->now.tv_sec;
810 keyring->last_used_at = ctx->now.tv_sec;
811 while (sp > 0)
812 stack[--sp].keyring->last_used_at = ctx->now.tv_sec;
813 }
814 kleave(" = true");
815 return true;
816}
817
David Howells973c9f42011-01-20 16:38:33 +0000818/**
819 * keyring_search_aux - Search a keyring tree for a key matching some criteria
820 * @keyring_ref: A pointer to the keyring with possession indicator.
David Howells4bdf0bc2013-09-24 10:35:15 +0100821 * @ctx: The keyring search context.
David Howells973c9f42011-01-20 16:38:33 +0000822 *
823 * Search the supplied keyring tree for a key that matches the criteria given.
824 * The root keyring and any linked keyrings must grant Search permission to the
825 * caller to be searchable and keys can only be found if they too grant Search
826 * to the caller. The possession flag on the root keyring pointer controls use
827 * of the possessor bits in permissions checking of the entire tree. In
828 * addition, the LSM gets to forbid keyring searches and key matches.
829 *
830 * The search is performed as a breadth-then-depth search up to the prescribed
831 * limit (KEYRING_SEARCH_MAX_DEPTH).
832 *
833 * Keys are matched to the type provided and are then filtered by the match
834 * function, which is given the description to use in any way it sees fit. The
835 * match function may use any attributes of a key that it wishes to to
836 * determine the match. Normally the match function from the key type would be
837 * used.
838 *
David Howellsb2a4df22013-09-24 10:35:18 +0100839 * RCU can be used to prevent the keyring key lists from disappearing without
840 * the need to take lots of locks.
David Howells973c9f42011-01-20 16:38:33 +0000841 *
842 * Returns a pointer to the found key and increments the key usage count if
843 * successful; -EAGAIN if no matching keys were found, or if expired or revoked
844 * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
845 * specified keyring wasn't a keyring.
846 *
847 * In the case of a successful return, the possession attribute from
848 * @keyring_ref is propagated to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 */
David Howells664cceb2005-09-28 17:03:15 +0100850key_ref_t keyring_search_aux(key_ref_t keyring_ref,
David Howells4bdf0bc2013-09-24 10:35:15 +0100851 struct keyring_search_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852{
David Howellsb2a4df22013-09-24 10:35:18 +0100853 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 long err;
David Howellsb2a4df22013-09-24 10:35:18 +0100855
856 ctx->iterator = keyring_search_iterator;
857 ctx->possessed = is_key_possessed(keyring_ref);
858 ctx->result = ERR_PTR(-EAGAIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859
David Howells664cceb2005-09-28 17:03:15 +0100860 keyring = key_ref_to_ptr(keyring_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 key_check(keyring);
862
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100864 return ERR_PTR(-ENOTDIR);
865
866 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) {
David Howellsf5895942014-03-14 17:44:49 +0000867 err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH);
David Howellsb2a4df22013-09-24 10:35:18 +0100868 if (err < 0)
869 return ERR_PTR(err);
870 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871
David Howells664cceb2005-09-28 17:03:15 +0100872 rcu_read_lock();
David Howells4bdf0bc2013-09-24 10:35:15 +0100873 ctx->now = current_kernel_time();
David Howellsb2a4df22013-09-24 10:35:18 +0100874 if (search_nested_keyrings(keyring, ctx))
875 __key_get(key_ref_to_ptr(ctx->result));
David Howells76d8aea2005-06-23 22:00:49 -0700876 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +0100877 return ctx->result;
David Howellsa8b17ed2011-01-20 16:38:27 +0000878}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
David Howells973c9f42011-01-20 16:38:33 +0000880/**
881 * keyring_search - Search the supplied keyring tree for a matching key
882 * @keyring: The root of the keyring tree to be searched.
883 * @type: The type of keyring we want to find.
884 * @description: The name of the keyring we want to find.
885 *
886 * As keyring_search_aux() above, but using the current task's credentials and
David Howellsb2a4df22013-09-24 10:35:18 +0100887 * type's default matching function and preferred search method.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 */
David Howells664cceb2005-09-28 17:03:15 +0100889key_ref_t keyring_search(key_ref_t keyring,
890 struct key_type *type,
891 const char *description)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892{
David Howells4bdf0bc2013-09-24 10:35:15 +0100893 struct keyring_search_context ctx = {
894 .index_key.type = type,
895 .index_key.description = description,
896 .cred = current_cred(),
David Howellsc06cfb02014-09-16 17:36:06 +0100897 .match_data.cmp = key_default_cmp,
David Howells46291952014-09-16 17:36:02 +0100898 .match_data.raw_data = description,
899 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
900 .flags = KEYRING_SEARCH_DO_STATE_CHECK,
David Howells4bdf0bc2013-09-24 10:35:15 +0100901 };
David Howells46291952014-09-16 17:36:02 +0100902 key_ref_t key;
903 int ret;
David Howells4bdf0bc2013-09-24 10:35:15 +0100904
David Howells46291952014-09-16 17:36:02 +0100905 if (type->match_preparse) {
906 ret = type->match_preparse(&ctx.match_data);
907 if (ret < 0)
908 return ERR_PTR(ret);
909 }
910
911 key = keyring_search_aux(keyring, &ctx);
912
913 if (type->match_free)
914 type->match_free(&ctx.match_data);
915 return key;
David Howellsa8b17ed2011-01-20 16:38:27 +0000916}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917EXPORT_SYMBOL(keyring_search);
918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919/*
David Howellsb2a4df22013-09-24 10:35:18 +0100920 * Search the given keyring for a key that might be updated.
David Howells973c9f42011-01-20 16:38:33 +0000921 *
922 * The caller must guarantee that the keyring is a keyring and that the
David Howellsb2a4df22013-09-24 10:35:18 +0100923 * permission is granted to modify the keyring as no check is made here. The
924 * caller must also hold a lock on the keyring semaphore.
David Howells973c9f42011-01-20 16:38:33 +0000925 *
926 * Returns a pointer to the found key with usage count incremented if
David Howellsb2a4df22013-09-24 10:35:18 +0100927 * successful and returns NULL if not found. Revoked and invalidated keys are
928 * skipped over.
David Howells973c9f42011-01-20 16:38:33 +0000929 *
930 * If successful, the possession indicator is propagated from the keyring ref
931 * to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 */
David Howellsb2a4df22013-09-24 10:35:18 +0100933key_ref_t find_key_to_update(key_ref_t keyring_ref,
934 const struct keyring_index_key *index_key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935{
David Howells664cceb2005-09-28 17:03:15 +0100936 struct key *keyring, *key;
David Howellsb2a4df22013-09-24 10:35:18 +0100937 const void *object;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938
David Howells664cceb2005-09-28 17:03:15 +0100939 keyring = key_ref_to_ptr(keyring_ref);
David Howells664cceb2005-09-28 17:03:15 +0100940
David Howellsb2a4df22013-09-24 10:35:18 +0100941 kenter("{%d},{%s,%s}",
942 keyring->serial, index_key->type->name, index_key->description);
David Howells76d8aea2005-06-23 22:00:49 -0700943
David Howellsb2a4df22013-09-24 10:35:18 +0100944 object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops,
945 index_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946
David Howellsb2a4df22013-09-24 10:35:18 +0100947 if (object)
948 goto found;
949
950 kleave(" = NULL");
951 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952
Justin P. Mattockc5b60b52010-04-21 00:02:11 -0700953found:
David Howellsb2a4df22013-09-24 10:35:18 +0100954 key = keyring_ptr_to_key(object);
955 if (key->flags & ((1 << KEY_FLAG_INVALIDATED) |
956 (1 << KEY_FLAG_REVOKED))) {
957 kleave(" = NULL [x]");
958 return NULL;
959 }
David Howellsccc3e6d2013-09-24 10:35:16 +0100960 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +0100961 kleave(" = {%d}", key->serial);
962 return make_key_ref(key, is_key_possessed(keyring_ref));
David Howellsa8b17ed2011-01-20 16:38:27 +0000963}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965/*
David Howells973c9f42011-01-20 16:38:33 +0000966 * Find a keyring with the specified name.
967 *
968 * All named keyrings in the current user namespace are searched, provided they
969 * grant Search permission directly to the caller (unless this check is
970 * skipped). Keyrings whose usage points have reached zero or who have been
971 * revoked are skipped.
972 *
973 * Returns a pointer to the keyring with the keyring's refcount having being
974 * incremented on success. -ENOKEY is returned if a key could not be found.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 */
David Howells69664cf2008-04-29 01:01:31 -0700976struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977{
978 struct key *keyring;
979 int bucket;
980
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 if (!name)
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100982 return ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983
984 bucket = keyring_hash(name);
985
986 read_lock(&keyring_name_lock);
987
988 if (keyring_name_hash[bucket].next) {
989 /* search this hash bucket for a keyring with a matching name
990 * that's readable and that hasn't been revoked */
991 list_for_each_entry(keyring,
992 &keyring_name_hash[bucket],
993 type_data.link
994 ) {
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800995 if (!kuid_has_mapping(current_user_ns(), keyring->user->uid))
Serge E. Hallyn2ea190d2009-02-26 18:27:55 -0600996 continue;
997
David Howells76d8aea2005-06-23 22:00:49 -0700998 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 continue;
1000
1001 if (strcmp(keyring->description, name) != 0)
1002 continue;
1003
David Howells69664cf2008-04-29 01:01:31 -07001004 if (!skip_perm_check &&
1005 key_permission(make_key_ref(keyring, 0),
David Howellsf5895942014-03-14 17:44:49 +00001006 KEY_NEED_SEARCH) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 continue;
1008
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001009 /* we've got a match but we might end up racing with
1010 * key_cleanup() if the keyring is currently 'dead'
1011 * (ie. it has a zero usage count) */
1012 if (!atomic_inc_not_zero(&keyring->usage))
1013 continue;
David Howells31d5a792012-05-11 10:56:56 +01001014 keyring->last_used_at = current_kernel_time().tv_sec;
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001015 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 }
1017 }
1018
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 keyring = ERR_PTR(-ENOKEY);
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001020out:
1021 read_unlock(&keyring_name_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 return keyring;
David Howellsa8b17ed2011-01-20 16:38:27 +00001023}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024
David Howellsb2a4df22013-09-24 10:35:18 +01001025static int keyring_detect_cycle_iterator(const void *object,
1026 void *iterator_data)
1027{
1028 struct keyring_search_context *ctx = iterator_data;
1029 const struct key *key = keyring_ptr_to_key(object);
1030
1031 kenter("{%d}", key->serial);
1032
David Howells979e0d72014-03-09 08:21:58 +00001033 /* We might get a keyring with matching index-key that is nonetheless a
1034 * different keyring. */
David Howells46291952014-09-16 17:36:02 +01001035 if (key != ctx->match_data.raw_data)
David Howells979e0d72014-03-09 08:21:58 +00001036 return 0;
1037
David Howellsb2a4df22013-09-24 10:35:18 +01001038 ctx->result = ERR_PTR(-EDEADLK);
1039 return 1;
1040}
1041
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042/*
David Howells973c9f42011-01-20 16:38:33 +00001043 * See if a cycle will will be created by inserting acyclic tree B in acyclic
1044 * tree A at the topmost level (ie: as a direct child of A).
1045 *
1046 * Since we are adding B to A at the top level, checking for cycles should just
1047 * be a matter of seeing if node A is somewhere in tree B.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001048 */
1049static int keyring_detect_cycle(struct key *A, struct key *B)
1050{
David Howellsb2a4df22013-09-24 10:35:18 +01001051 struct keyring_search_context ctx = {
David Howells46291952014-09-16 17:36:02 +01001052 .index_key = A->index_key,
1053 .match_data.raw_data = A,
1054 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
1055 .iterator = keyring_detect_cycle_iterator,
1056 .flags = (KEYRING_SEARCH_NO_STATE_CHECK |
1057 KEYRING_SEARCH_NO_UPDATE_TIME |
1058 KEYRING_SEARCH_NO_CHECK_PERM |
1059 KEYRING_SEARCH_DETECT_TOO_DEEP),
David Howellsb2a4df22013-09-24 10:35:18 +01001060 };
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061
David Howells76d8aea2005-06-23 22:00:49 -07001062 rcu_read_lock();
David Howellsb2a4df22013-09-24 10:35:18 +01001063 search_nested_keyrings(B, &ctx);
David Howells76d8aea2005-06-23 22:00:49 -07001064 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +01001065 return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result);
David Howellsf70e2e02010-04-30 14:32:39 +01001066}
David Howellscab8eb52006-01-08 01:02:45 -08001067
David Howellscab8eb52006-01-08 01:02:45 -08001068/*
David Howells973c9f42011-01-20 16:38:33 +00001069 * Preallocate memory so that a key can be linked into to a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 */
David Howellsb2a4df22013-09-24 10:35:18 +01001071int __key_link_begin(struct key *keyring,
1072 const struct keyring_index_key *index_key,
1073 struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001074 __acquires(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001075 __acquires(&keyring_serialise_link_sem)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001076{
David Howellsb2a4df22013-09-24 10:35:18 +01001077 struct assoc_array_edit *edit;
1078 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001079
David Howells16feef42013-09-24 10:35:15 +01001080 kenter("%d,%s,%s,",
David Howellsb2a4df22013-09-24 10:35:18 +01001081 keyring->serial, index_key->type->name, index_key->description);
1082
1083 BUG_ON(index_key->desc_len == 0);
David Howellsf70e2e02010-04-30 14:32:39 +01001084
1085 if (keyring->type != &key_type_keyring)
1086 return -ENOTDIR;
1087
1088 down_write(&keyring->sem);
1089
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 ret = -EKEYREVOKED;
David Howells76d8aea2005-06-23 22:00:49 -07001091 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
David Howellsf70e2e02010-04-30 14:32:39 +01001092 goto error_krsem;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
David Howellsf70e2e02010-04-30 14:32:39 +01001094 /* serialise link/link calls to prevent parallel calls causing a cycle
1095 * when linking two keyring in opposite orders */
David Howells16feef42013-09-24 10:35:15 +01001096 if (index_key->type == &key_type_keyring)
David Howells553d6032010-04-30 14:32:28 +01001097 down_write(&keyring_serialise_link_sem);
1098
David Howellsb2a4df22013-09-24 10:35:18 +01001099 /* Create an edit script that will insert/replace the key in the
1100 * keyring tree.
1101 */
1102 edit = assoc_array_insert(&keyring->keys,
1103 &keyring_assoc_array_ops,
1104 index_key,
1105 NULL);
1106 if (IS_ERR(edit)) {
1107 ret = PTR_ERR(edit);
David Howells034faeb2013-10-30 11:15:24 +00001108 goto error_sem;
1109 }
1110
1111 /* If we're not replacing a link in-place then we're going to need some
1112 * extra quota.
1113 */
1114 if (!edit->dead_leaf) {
1115 ret = key_payload_reserve(keyring,
1116 keyring->datalen + KEYQUOTA_LINK_BYTES);
1117 if (ret < 0)
1118 goto error_cancel;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 }
1120
David Howellsb2a4df22013-09-24 10:35:18 +01001121 *_edit = edit;
David Howellsf70e2e02010-04-30 14:32:39 +01001122 kleave(" = 0");
1123 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124
David Howells034faeb2013-10-30 11:15:24 +00001125error_cancel:
1126 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001127error_sem:
David Howells16feef42013-09-24 10:35:15 +01001128 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001129 up_write(&keyring_serialise_link_sem);
1130error_krsem:
1131 up_write(&keyring->sem);
1132 kleave(" = %d", ret);
1133 return ret;
1134}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135
David Howellsf70e2e02010-04-30 14:32:39 +01001136/*
David Howells973c9f42011-01-20 16:38:33 +00001137 * Check already instantiated keys aren't going to be a problem.
1138 *
1139 * The caller must have called __key_link_begin(). Don't need to call this for
1140 * keys that were created since __key_link_begin() was called.
David Howellsf70e2e02010-04-30 14:32:39 +01001141 */
1142int __key_link_check_live_key(struct key *keyring, struct key *key)
1143{
1144 if (key->type == &key_type_keyring)
1145 /* check that we aren't going to create a cycle by linking one
1146 * keyring to another */
1147 return keyring_detect_cycle(keyring, key);
1148 return 0;
1149}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150
David Howellsf70e2e02010-04-30 14:32:39 +01001151/*
David Howells973c9f42011-01-20 16:38:33 +00001152 * Link a key into to a keyring.
1153 *
1154 * Must be called with __key_link_begin() having being called. Discards any
1155 * already extant link to matching key if there is one, so that each keyring
1156 * holds at most one link to any given key of a particular type+description
1157 * combination.
David Howellsf70e2e02010-04-30 14:32:39 +01001158 */
David Howellsb2a4df22013-09-24 10:35:18 +01001159void __key_link(struct key *key, struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001160{
David Howellsccc3e6d2013-09-24 10:35:16 +01001161 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +01001162 assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key));
1163 assoc_array_apply_edit(*_edit);
1164 *_edit = NULL;
David Howellsf70e2e02010-04-30 14:32:39 +01001165}
1166
1167/*
David Howells973c9f42011-01-20 16:38:33 +00001168 * Finish linking a key into to a keyring.
1169 *
1170 * Must be called with __key_link_begin() having being called.
David Howellsf70e2e02010-04-30 14:32:39 +01001171 */
David Howells16feef42013-09-24 10:35:15 +01001172void __key_link_end(struct key *keyring,
1173 const struct keyring_index_key *index_key,
David Howellsb2a4df22013-09-24 10:35:18 +01001174 struct assoc_array_edit *edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001175 __releases(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001176 __releases(&keyring_serialise_link_sem)
David Howellsf70e2e02010-04-30 14:32:39 +01001177{
David Howells16feef42013-09-24 10:35:15 +01001178 BUG_ON(index_key->type == NULL);
David Howellsb2a4df22013-09-24 10:35:18 +01001179 kenter("%d,%s,", keyring->serial, index_key->type->name);
David Howellsf70e2e02010-04-30 14:32:39 +01001180
David Howells16feef42013-09-24 10:35:15 +01001181 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001182 up_write(&keyring_serialise_link_sem);
1183
David Howells034faeb2013-10-30 11:15:24 +00001184 if (edit && !edit->dead_leaf) {
David Howellsb2a4df22013-09-24 10:35:18 +01001185 key_payload_reserve(keyring,
1186 keyring->datalen - KEYQUOTA_LINK_BYTES);
1187 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001188 }
1189 up_write(&keyring->sem);
1190}
1191
David Howells973c9f42011-01-20 16:38:33 +00001192/**
1193 * key_link - Link a key to a keyring
1194 * @keyring: The keyring to make the link in.
1195 * @key: The key to link to.
1196 *
1197 * Make a link in a keyring to a key, such that the keyring holds a reference
1198 * on that key and the key can potentially be found by searching that keyring.
1199 *
1200 * This function will write-lock the keyring's semaphore and will consume some
1201 * of the user's key data quota to hold the link.
1202 *
1203 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
1204 * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
1205 * full, -EDQUOT if there is insufficient key data quota remaining to add
1206 * another link or -ENOMEM if there's insufficient memory.
1207 *
1208 * It is assumed that the caller has checked that it is permitted for a link to
1209 * be made (the keyring should have Write permission and the key Link
1210 * permission).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211 */
1212int key_link(struct key *keyring, struct key *key)
1213{
David Howellsb2a4df22013-09-24 10:35:18 +01001214 struct assoc_array_edit *edit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 int ret;
1216
David Howellsb2a4df22013-09-24 10:35:18 +01001217 kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage));
1218
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 key_check(keyring);
1220 key_check(key);
1221
David Howells008643b2013-08-30 16:07:37 +01001222 if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) &&
1223 !test_bit(KEY_FLAG_TRUSTED, &key->flags))
1224 return -EPERM;
1225
David Howellsb2a4df22013-09-24 10:35:18 +01001226 ret = __key_link_begin(keyring, &key->index_key, &edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001227 if (ret == 0) {
David Howellsb2a4df22013-09-24 10:35:18 +01001228 kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));
David Howellsf70e2e02010-04-30 14:32:39 +01001229 ret = __key_link_check_live_key(keyring, key);
1230 if (ret == 0)
David Howellsb2a4df22013-09-24 10:35:18 +01001231 __key_link(key, &edit);
1232 __key_link_end(keyring, &key->index_key, edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001233 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234
David Howellsb2a4df22013-09-24 10:35:18 +01001235 kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236 return ret;
David Howellsf70e2e02010-04-30 14:32:39 +01001237}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238EXPORT_SYMBOL(key_link);
1239
David Howells973c9f42011-01-20 16:38:33 +00001240/**
1241 * key_unlink - Unlink the first link to a key from a keyring.
1242 * @keyring: The keyring to remove the link from.
1243 * @key: The key the link is to.
1244 *
1245 * Remove a link from a keyring to a key.
1246 *
1247 * This function will write-lock the keyring's semaphore.
1248 *
1249 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
1250 * the key isn't linked to by the keyring or -ENOMEM if there's insufficient
1251 * memory.
1252 *
1253 * It is assumed that the caller has checked that it is permitted for a link to
1254 * be removed (the keyring should have Write permission; no permissions are
1255 * required on the key).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 */
1257int key_unlink(struct key *keyring, struct key *key)
1258{
David Howellsb2a4df22013-09-24 10:35:18 +01001259 struct assoc_array_edit *edit;
1260 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
1262 key_check(keyring);
1263 key_check(key);
1264
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +01001266 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267
1268 down_write(&keyring->sem);
1269
David Howellsb2a4df22013-09-24 10:35:18 +01001270 edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
1271 &key->index_key);
1272 if (IS_ERR(edit)) {
1273 ret = PTR_ERR(edit);
1274 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 ret = -ENOENT;
David Howellsb2a4df22013-09-24 10:35:18 +01001277 if (edit == NULL)
1278 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279
David Howellsb2a4df22013-09-24 10:35:18 +01001280 assoc_array_apply_edit(edit);
David Howells034faeb2013-10-30 11:15:24 +00001281 key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001282 ret = 0;
1283
David Howells76d8aea2005-06-23 22:00:49 -07001284error:
David Howells76d8aea2005-06-23 22:00:49 -07001285 up_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001286 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001287}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288EXPORT_SYMBOL(key_unlink);
1289
David Howells973c9f42011-01-20 16:38:33 +00001290/**
1291 * keyring_clear - Clear a keyring
1292 * @keyring: The keyring to clear.
1293 *
1294 * Clear the contents of the specified keyring.
1295 *
1296 * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 */
1298int keyring_clear(struct key *keyring)
1299{
David Howellsb2a4df22013-09-24 10:35:18 +01001300 struct assoc_array_edit *edit;
David Howells76d8aea2005-06-23 22:00:49 -07001301 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302
David Howellsb2a4df22013-09-24 10:35:18 +01001303 if (keyring->type != &key_type_keyring)
1304 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305
David Howellsb2a4df22013-09-24 10:35:18 +01001306 down_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307
David Howellsb2a4df22013-09-24 10:35:18 +01001308 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1309 if (IS_ERR(edit)) {
1310 ret = PTR_ERR(edit);
1311 } else {
1312 if (edit)
1313 assoc_array_apply_edit(edit);
1314 key_payload_reserve(keyring, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 ret = 0;
1316 }
1317
David Howellsb2a4df22013-09-24 10:35:18 +01001318 up_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001320}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321EXPORT_SYMBOL(keyring_clear);
David Howells31204ed2006-06-26 00:24:51 -07001322
David Howells31204ed2006-06-26 00:24:51 -07001323/*
David Howells973c9f42011-01-20 16:38:33 +00001324 * Dispose of the links from a revoked keyring.
1325 *
1326 * This is called with the key sem write-locked.
David Howells31204ed2006-06-26 00:24:51 -07001327 */
1328static void keyring_revoke(struct key *keyring)
1329{
David Howellsb2a4df22013-09-24 10:35:18 +01001330 struct assoc_array_edit *edit;
David Howellsf0641cb2010-04-30 14:32:18 +01001331
David Howellsb2a4df22013-09-24 10:35:18 +01001332 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1333 if (!IS_ERR(edit)) {
1334 if (edit)
1335 assoc_array_apply_edit(edit);
1336 key_payload_reserve(keyring, 0);
David Howells31204ed2006-06-26 00:24:51 -07001337 }
David Howellsa8b17ed2011-01-20 16:38:27 +00001338}
David Howells5d135442009-09-02 09:14:00 +01001339
David Howells62fe3182013-11-14 13:02:31 +00001340static bool keyring_gc_select_iterator(void *object, void *iterator_data)
David Howellsb2a4df22013-09-24 10:35:18 +01001341{
1342 struct key *key = keyring_ptr_to_key(object);
1343 time_t *limit = iterator_data;
1344
1345 if (key_is_dead(key, *limit))
1346 return false;
1347 key_get(key);
1348 return true;
1349}
1350
David Howells62fe3182013-11-14 13:02:31 +00001351static int keyring_gc_check_iterator(const void *object, void *iterator_data)
1352{
1353 const struct key *key = keyring_ptr_to_key(object);
1354 time_t *limit = iterator_data;
1355
1356 key_check(key);
1357 return key_is_dead(key, *limit);
1358}
1359
David Howells5d135442009-09-02 09:14:00 +01001360/*
David Howells62fe3182013-11-14 13:02:31 +00001361 * Garbage collect pointers from a keyring.
David Howells973c9f42011-01-20 16:38:33 +00001362 *
David Howells62fe3182013-11-14 13:02:31 +00001363 * Not called with any locks held. The keyring's key struct will not be
1364 * deallocated under us as only our caller may deallocate it.
David Howells5d135442009-09-02 09:14:00 +01001365 */
1366void keyring_gc(struct key *keyring, time_t limit)
1367{
David Howells62fe3182013-11-14 13:02:31 +00001368 int result;
David Howells5d135442009-09-02 09:14:00 +01001369
David Howells62fe3182013-11-14 13:02:31 +00001370 kenter("%x{%s}", keyring->serial, keyring->description ?: "");
1371
1372 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
1373 (1 << KEY_FLAG_REVOKED)))
1374 goto dont_gc;
1375
1376 /* scan the keyring looking for dead keys */
1377 rcu_read_lock();
1378 result = assoc_array_iterate(&keyring->keys,
1379 keyring_gc_check_iterator, &limit);
1380 rcu_read_unlock();
1381 if (result == true)
1382 goto do_gc;
1383
1384dont_gc:
1385 kleave(" [no gc]");
1386 return;
1387
1388do_gc:
David Howells5d135442009-09-02 09:14:00 +01001389 down_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001390 assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops,
David Howells62fe3182013-11-14 13:02:31 +00001391 keyring_gc_select_iterator, &limit);
David Howells5d135442009-09-02 09:14:00 +01001392 up_write(&keyring->sem);
David Howells62fe3182013-11-14 13:02:31 +00001393 kleave(" [gc]");
David Howells5d135442009-09-02 09:14:00 +01001394}