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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) {
549 ctx->result = ERR_PTR(-EKEYEXPIRED);
550 kleave(" = %d [expire]", ctx->skipped_ret);
551 goto skipped;
552 }
553 }
554
555 /* keys that don't match */
David Howells46291952014-09-16 17:36:02 +0100556 if (!ctx->match_data.cmp(key, &ctx->match_data)) {
David Howellsb2a4df22013-09-24 10:35:18 +0100557 kleave(" = 0 [!match]");
558 return 0;
559 }
560
561 /* key must have search permissions */
562 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
563 key_task_permission(make_key_ref(key, ctx->possessed),
David Howellsf5895942014-03-14 17:44:49 +0000564 ctx->cred, KEY_NEED_SEARCH) < 0) {
David Howellsb2a4df22013-09-24 10:35:18 +0100565 ctx->result = ERR_PTR(-EACCES);
566 kleave(" = %d [!perm]", ctx->skipped_ret);
567 goto skipped;
568 }
569
570 if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
571 /* we set a different error code if we pass a negative key */
572 if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
David Howells74792b02013-10-30 11:15:24 +0000573 smp_rmb();
David Howellsb2a4df22013-09-24 10:35:18 +0100574 ctx->result = ERR_PTR(key->type_data.reject_error);
575 kleave(" = %d [neg]", ctx->skipped_ret);
576 goto skipped;
577 }
578 }
579
580 /* Found */
581 ctx->result = make_key_ref(key, ctx->possessed);
582 kleave(" = 1 [found]");
583 return 1;
584
585skipped:
586 return ctx->skipped_ret;
587}
588
589/*
590 * Search inside a keyring for a key. We can search by walking to it
591 * directly based on its index-key or we can iterate over the entire
592 * tree looking for it, based on the match function.
593 */
594static int search_keyring(struct key *keyring, struct keyring_search_context *ctx)
595{
David Howells46291952014-09-16 17:36:02 +0100596 if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_DIRECT) {
David Howellsb2a4df22013-09-24 10:35:18 +0100597 const void *object;
598
599 object = assoc_array_find(&keyring->keys,
600 &keyring_assoc_array_ops,
601 &ctx->index_key);
602 return object ? ctx->iterator(object, ctx) : 0;
603 }
604 return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx);
605}
606
607/*
608 * Search a tree of keyrings that point to other keyrings up to the maximum
609 * depth.
610 */
611static bool search_nested_keyrings(struct key *keyring,
612 struct keyring_search_context *ctx)
613{
614 struct {
615 struct key *keyring;
616 struct assoc_array_node *node;
617 int slot;
618 } stack[KEYRING_SEARCH_MAX_DEPTH];
619
620 struct assoc_array_shortcut *shortcut;
621 struct assoc_array_node *node;
622 struct assoc_array_ptr *ptr;
623 struct key *key;
624 int sp = 0, slot;
625
626 kenter("{%d},{%s,%s}",
627 keyring->serial,
628 ctx->index_key.type->name,
629 ctx->index_key.description);
630
631 if (ctx->index_key.description)
632 ctx->index_key.desc_len = strlen(ctx->index_key.description);
633
634 /* Check to see if this top-level keyring is what we are looking for
635 * and whether it is valid or not.
636 */
David Howells46291952014-09-16 17:36:02 +0100637 if (ctx->match_data.lookup_type == KEYRING_SEARCH_LOOKUP_ITERATE ||
David Howellsb2a4df22013-09-24 10:35:18 +0100638 keyring_compare_object(keyring, &ctx->index_key)) {
639 ctx->skipped_ret = 2;
640 ctx->flags |= KEYRING_SEARCH_DO_STATE_CHECK;
641 switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) {
642 case 1:
643 goto found;
644 case 2:
645 return false;
646 default:
647 break;
648 }
649 }
650
651 ctx->skipped_ret = 0;
652 if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK)
653 ctx->flags &= ~KEYRING_SEARCH_DO_STATE_CHECK;
654
655 /* Start processing a new keyring */
656descend_to_keyring:
657 kdebug("descend to %d", keyring->serial);
658 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
659 (1 << KEY_FLAG_REVOKED)))
660 goto not_this_keyring;
661
662 /* Search through the keys in this keyring before its searching its
663 * subtrees.
664 */
665 if (search_keyring(keyring, ctx))
666 goto found;
667
668 /* Then manually iterate through the keyrings nested in this one.
669 *
670 * Start from the root node of the index tree. Because of the way the
671 * hash function has been set up, keyrings cluster on the leftmost
672 * branch of the root node (root slot 0) or in the root node itself.
673 * Non-keyrings avoid the leftmost branch of the root entirely (root
674 * slots 1-15).
675 */
676 ptr = ACCESS_ONCE(keyring->keys.root);
677 if (!ptr)
678 goto not_this_keyring;
679
680 if (assoc_array_ptr_is_shortcut(ptr)) {
681 /* If the root is a shortcut, either the keyring only contains
682 * keyring pointers (everything clusters behind root slot 0) or
683 * doesn't contain any keyring pointers.
684 */
685 shortcut = assoc_array_ptr_to_shortcut(ptr);
686 smp_read_barrier_depends();
687 if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
688 goto not_this_keyring;
689
690 ptr = ACCESS_ONCE(shortcut->next_node);
691 node = assoc_array_ptr_to_node(ptr);
692 goto begin_node;
693 }
694
695 node = assoc_array_ptr_to_node(ptr);
696 smp_read_barrier_depends();
697
698 ptr = node->slots[0];
699 if (!assoc_array_ptr_is_meta(ptr))
700 goto begin_node;
701
702descend_to_node:
703 /* Descend to a more distal node in this keyring's content tree and go
704 * through that.
705 */
706 kdebug("descend");
707 if (assoc_array_ptr_is_shortcut(ptr)) {
708 shortcut = assoc_array_ptr_to_shortcut(ptr);
709 smp_read_barrier_depends();
710 ptr = ACCESS_ONCE(shortcut->next_node);
711 BUG_ON(!assoc_array_ptr_is_node(ptr));
David Howellsb2a4df22013-09-24 10:35:18 +0100712 }
David Howells9c5e45d2013-12-02 11:24:19 +0000713 node = assoc_array_ptr_to_node(ptr);
David Howellsb2a4df22013-09-24 10:35:18 +0100714
715begin_node:
716 kdebug("begin_node");
717 smp_read_barrier_depends();
718 slot = 0;
719ascend_to_node:
720 /* Go through the slots in a node */
721 for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
722 ptr = ACCESS_ONCE(node->slots[slot]);
723
724 if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)
725 goto descend_to_node;
726
727 if (!keyring_ptr_is_keyring(ptr))
728 continue;
729
730 key = keyring_ptr_to_key(ptr);
731
732 if (sp >= KEYRING_SEARCH_MAX_DEPTH) {
733 if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) {
734 ctx->result = ERR_PTR(-ELOOP);
735 return false;
736 }
737 goto not_this_keyring;
738 }
739
740 /* Search a nested keyring */
741 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
742 key_task_permission(make_key_ref(key, ctx->possessed),
David Howellsf5895942014-03-14 17:44:49 +0000743 ctx->cred, KEY_NEED_SEARCH) < 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100744 continue;
745
746 /* stack the current position */
747 stack[sp].keyring = keyring;
748 stack[sp].node = node;
749 stack[sp].slot = slot;
750 sp++;
751
752 /* begin again with the new keyring */
753 keyring = key;
754 goto descend_to_keyring;
755 }
756
757 /* We've dealt with all the slots in the current node, so now we need
758 * to ascend to the parent and continue processing there.
759 */
760 ptr = ACCESS_ONCE(node->back_pointer);
761 slot = node->parent_slot;
762
763 if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
764 shortcut = assoc_array_ptr_to_shortcut(ptr);
765 smp_read_barrier_depends();
766 ptr = ACCESS_ONCE(shortcut->back_pointer);
767 slot = shortcut->parent_slot;
768 }
769 if (!ptr)
770 goto not_this_keyring;
771 node = assoc_array_ptr_to_node(ptr);
772 smp_read_barrier_depends();
773 slot++;
774
775 /* If we've ascended to the root (zero backpointer), we must have just
776 * finished processing the leftmost branch rather than the root slots -
777 * so there can't be any more keyrings for us to find.
778 */
779 if (node->back_pointer) {
780 kdebug("ascend %d", slot);
781 goto ascend_to_node;
782 }
783
784 /* The keyring we're looking at was disqualified or didn't contain a
785 * matching key.
786 */
787not_this_keyring:
788 kdebug("not_this_keyring %d", sp);
789 if (sp <= 0) {
790 kleave(" = false");
791 return false;
792 }
793
794 /* Resume the processing of a keyring higher up in the tree */
795 sp--;
796 keyring = stack[sp].keyring;
797 node = stack[sp].node;
798 slot = stack[sp].slot + 1;
799 kdebug("ascend to %d [%d]", keyring->serial, slot);
800 goto ascend_to_node;
801
802 /* We found a viable match */
803found:
804 key = key_ref_to_ptr(ctx->result);
805 key_check(key);
806 if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) {
807 key->last_used_at = ctx->now.tv_sec;
808 keyring->last_used_at = ctx->now.tv_sec;
809 while (sp > 0)
810 stack[--sp].keyring->last_used_at = ctx->now.tv_sec;
811 }
812 kleave(" = true");
813 return true;
814}
815
David Howells973c9f42011-01-20 16:38:33 +0000816/**
817 * keyring_search_aux - Search a keyring tree for a key matching some criteria
818 * @keyring_ref: A pointer to the keyring with possession indicator.
David Howells4bdf0bc2013-09-24 10:35:15 +0100819 * @ctx: The keyring search context.
David Howells973c9f42011-01-20 16:38:33 +0000820 *
821 * Search the supplied keyring tree for a key that matches the criteria given.
822 * The root keyring and any linked keyrings must grant Search permission to the
823 * caller to be searchable and keys can only be found if they too grant Search
824 * to the caller. The possession flag on the root keyring pointer controls use
825 * of the possessor bits in permissions checking of the entire tree. In
826 * addition, the LSM gets to forbid keyring searches and key matches.
827 *
828 * The search is performed as a breadth-then-depth search up to the prescribed
829 * limit (KEYRING_SEARCH_MAX_DEPTH).
830 *
831 * Keys are matched to the type provided and are then filtered by the match
832 * function, which is given the description to use in any way it sees fit. The
833 * match function may use any attributes of a key that it wishes to to
834 * determine the match. Normally the match function from the key type would be
835 * used.
836 *
David Howellsb2a4df22013-09-24 10:35:18 +0100837 * RCU can be used to prevent the keyring key lists from disappearing without
838 * the need to take lots of locks.
David Howells973c9f42011-01-20 16:38:33 +0000839 *
840 * Returns a pointer to the found key and increments the key usage count if
841 * successful; -EAGAIN if no matching keys were found, or if expired or revoked
842 * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
843 * specified keyring wasn't a keyring.
844 *
845 * In the case of a successful return, the possession attribute from
846 * @keyring_ref is propagated to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 */
David Howells664cceb2005-09-28 17:03:15 +0100848key_ref_t keyring_search_aux(key_ref_t keyring_ref,
David Howells4bdf0bc2013-09-24 10:35:15 +0100849 struct keyring_search_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850{
David Howellsb2a4df22013-09-24 10:35:18 +0100851 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 long err;
David Howellsb2a4df22013-09-24 10:35:18 +0100853
854 ctx->iterator = keyring_search_iterator;
855 ctx->possessed = is_key_possessed(keyring_ref);
856 ctx->result = ERR_PTR(-EAGAIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857
David Howells664cceb2005-09-28 17:03:15 +0100858 keyring = key_ref_to_ptr(keyring_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 key_check(keyring);
860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100862 return ERR_PTR(-ENOTDIR);
863
864 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) {
David Howellsf5895942014-03-14 17:44:49 +0000865 err = key_task_permission(keyring_ref, ctx->cred, KEY_NEED_SEARCH);
David Howellsb2a4df22013-09-24 10:35:18 +0100866 if (err < 0)
867 return ERR_PTR(err);
868 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869
David Howells664cceb2005-09-28 17:03:15 +0100870 rcu_read_lock();
David Howells4bdf0bc2013-09-24 10:35:15 +0100871 ctx->now = current_kernel_time();
David Howellsb2a4df22013-09-24 10:35:18 +0100872 if (search_nested_keyrings(keyring, ctx))
873 __key_get(key_ref_to_ptr(ctx->result));
David Howells76d8aea2005-06-23 22:00:49 -0700874 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +0100875 return ctx->result;
David Howellsa8b17ed2011-01-20 16:38:27 +0000876}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877
David Howells973c9f42011-01-20 16:38:33 +0000878/**
879 * keyring_search - Search the supplied keyring tree for a matching key
880 * @keyring: The root of the keyring tree to be searched.
881 * @type: The type of keyring we want to find.
882 * @description: The name of the keyring we want to find.
883 *
884 * As keyring_search_aux() above, but using the current task's credentials and
David Howellsb2a4df22013-09-24 10:35:18 +0100885 * type's default matching function and preferred search method.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 */
David Howells664cceb2005-09-28 17:03:15 +0100887key_ref_t keyring_search(key_ref_t keyring,
888 struct key_type *type,
889 const char *description)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890{
David Howells4bdf0bc2013-09-24 10:35:15 +0100891 struct keyring_search_context ctx = {
892 .index_key.type = type,
893 .index_key.description = description,
894 .cred = current_cred(),
David Howellsc06cfb02014-09-16 17:36:06 +0100895 .match_data.cmp = key_default_cmp,
David Howells46291952014-09-16 17:36:02 +0100896 .match_data.raw_data = description,
897 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
898 .flags = KEYRING_SEARCH_DO_STATE_CHECK,
David Howells4bdf0bc2013-09-24 10:35:15 +0100899 };
David Howells46291952014-09-16 17:36:02 +0100900 key_ref_t key;
901 int ret;
David Howells4bdf0bc2013-09-24 10:35:15 +0100902
David Howells46291952014-09-16 17:36:02 +0100903 if (type->match_preparse) {
904 ret = type->match_preparse(&ctx.match_data);
905 if (ret < 0)
906 return ERR_PTR(ret);
907 }
908
909 key = keyring_search_aux(keyring, &ctx);
910
911 if (type->match_free)
912 type->match_free(&ctx.match_data);
913 return key;
David Howellsa8b17ed2011-01-20 16:38:27 +0000914}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915EXPORT_SYMBOL(keyring_search);
916
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917/*
David Howellsb2a4df22013-09-24 10:35:18 +0100918 * Search the given keyring for a key that might be updated.
David Howells973c9f42011-01-20 16:38:33 +0000919 *
920 * The caller must guarantee that the keyring is a keyring and that the
David Howellsb2a4df22013-09-24 10:35:18 +0100921 * permission is granted to modify the keyring as no check is made here. The
922 * caller must also hold a lock on the keyring semaphore.
David Howells973c9f42011-01-20 16:38:33 +0000923 *
924 * Returns a pointer to the found key with usage count incremented if
David Howellsb2a4df22013-09-24 10:35:18 +0100925 * successful and returns NULL if not found. Revoked and invalidated keys are
926 * skipped over.
David Howells973c9f42011-01-20 16:38:33 +0000927 *
928 * If successful, the possession indicator is propagated from the keyring ref
929 * to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930 */
David Howellsb2a4df22013-09-24 10:35:18 +0100931key_ref_t find_key_to_update(key_ref_t keyring_ref,
932 const struct keyring_index_key *index_key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933{
David Howells664cceb2005-09-28 17:03:15 +0100934 struct key *keyring, *key;
David Howellsb2a4df22013-09-24 10:35:18 +0100935 const void *object;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936
David Howells664cceb2005-09-28 17:03:15 +0100937 keyring = key_ref_to_ptr(keyring_ref);
David Howells664cceb2005-09-28 17:03:15 +0100938
David Howellsb2a4df22013-09-24 10:35:18 +0100939 kenter("{%d},{%s,%s}",
940 keyring->serial, index_key->type->name, index_key->description);
David Howells76d8aea2005-06-23 22:00:49 -0700941
David Howellsb2a4df22013-09-24 10:35:18 +0100942 object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops,
943 index_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
David Howellsb2a4df22013-09-24 10:35:18 +0100945 if (object)
946 goto found;
947
948 kleave(" = NULL");
949 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
Justin P. Mattockc5b60b52010-04-21 00:02:11 -0700951found:
David Howellsb2a4df22013-09-24 10:35:18 +0100952 key = keyring_ptr_to_key(object);
953 if (key->flags & ((1 << KEY_FLAG_INVALIDATED) |
954 (1 << KEY_FLAG_REVOKED))) {
955 kleave(" = NULL [x]");
956 return NULL;
957 }
David Howellsccc3e6d2013-09-24 10:35:16 +0100958 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +0100959 kleave(" = {%d}", key->serial);
960 return make_key_ref(key, is_key_possessed(keyring_ref));
David Howellsa8b17ed2011-01-20 16:38:27 +0000961}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963/*
David Howells973c9f42011-01-20 16:38:33 +0000964 * Find a keyring with the specified name.
965 *
966 * All named keyrings in the current user namespace are searched, provided they
967 * grant Search permission directly to the caller (unless this check is
968 * skipped). Keyrings whose usage points have reached zero or who have been
969 * revoked are skipped.
970 *
971 * Returns a pointer to the keyring with the keyring's refcount having being
972 * incremented on success. -ENOKEY is returned if a key could not be found.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973 */
David Howells69664cf2008-04-29 01:01:31 -0700974struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975{
976 struct key *keyring;
977 int bucket;
978
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979 if (!name)
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100980 return ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
982 bucket = keyring_hash(name);
983
984 read_lock(&keyring_name_lock);
985
986 if (keyring_name_hash[bucket].next) {
987 /* search this hash bucket for a keyring with a matching name
988 * that's readable and that hasn't been revoked */
989 list_for_each_entry(keyring,
990 &keyring_name_hash[bucket],
991 type_data.link
992 ) {
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800993 if (!kuid_has_mapping(current_user_ns(), keyring->user->uid))
Serge E. Hallyn2ea190d2009-02-26 18:27:55 -0600994 continue;
995
David Howells76d8aea2005-06-23 22:00:49 -0700996 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 continue;
998
999 if (strcmp(keyring->description, name) != 0)
1000 continue;
1001
David Howells69664cf2008-04-29 01:01:31 -07001002 if (!skip_perm_check &&
1003 key_permission(make_key_ref(keyring, 0),
David Howellsf5895942014-03-14 17:44:49 +00001004 KEY_NEED_SEARCH) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 continue;
1006
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001007 /* we've got a match but we might end up racing with
1008 * key_cleanup() if the keyring is currently 'dead'
1009 * (ie. it has a zero usage count) */
1010 if (!atomic_inc_not_zero(&keyring->usage))
1011 continue;
David Howells31d5a792012-05-11 10:56:56 +01001012 keyring->last_used_at = current_kernel_time().tv_sec;
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001013 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 }
1015 }
1016
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 keyring = ERR_PTR(-ENOKEY);
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +01001018out:
1019 read_unlock(&keyring_name_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 return keyring;
David Howellsa8b17ed2011-01-20 16:38:27 +00001021}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
David Howellsb2a4df22013-09-24 10:35:18 +01001023static int keyring_detect_cycle_iterator(const void *object,
1024 void *iterator_data)
1025{
1026 struct keyring_search_context *ctx = iterator_data;
1027 const struct key *key = keyring_ptr_to_key(object);
1028
1029 kenter("{%d}", key->serial);
1030
David Howells979e0d72014-03-09 08:21:58 +00001031 /* We might get a keyring with matching index-key that is nonetheless a
1032 * different keyring. */
David Howells46291952014-09-16 17:36:02 +01001033 if (key != ctx->match_data.raw_data)
David Howells979e0d72014-03-09 08:21:58 +00001034 return 0;
1035
David Howellsb2a4df22013-09-24 10:35:18 +01001036 ctx->result = ERR_PTR(-EDEADLK);
1037 return 1;
1038}
1039
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040/*
David Howells973c9f42011-01-20 16:38:33 +00001041 * See if a cycle will will be created by inserting acyclic tree B in acyclic
1042 * tree A at the topmost level (ie: as a direct child of A).
1043 *
1044 * Since we are adding B to A at the top level, checking for cycles should just
1045 * be a matter of seeing if node A is somewhere in tree B.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046 */
1047static int keyring_detect_cycle(struct key *A, struct key *B)
1048{
David Howellsb2a4df22013-09-24 10:35:18 +01001049 struct keyring_search_context ctx = {
David Howells46291952014-09-16 17:36:02 +01001050 .index_key = A->index_key,
1051 .match_data.raw_data = A,
1052 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
1053 .iterator = keyring_detect_cycle_iterator,
1054 .flags = (KEYRING_SEARCH_NO_STATE_CHECK |
1055 KEYRING_SEARCH_NO_UPDATE_TIME |
1056 KEYRING_SEARCH_NO_CHECK_PERM |
1057 KEYRING_SEARCH_DETECT_TOO_DEEP),
David Howellsb2a4df22013-09-24 10:35:18 +01001058 };
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059
David Howells76d8aea2005-06-23 22:00:49 -07001060 rcu_read_lock();
David Howellsb2a4df22013-09-24 10:35:18 +01001061 search_nested_keyrings(B, &ctx);
David Howells76d8aea2005-06-23 22:00:49 -07001062 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +01001063 return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result);
David Howellsf70e2e02010-04-30 14:32:39 +01001064}
David Howellscab8eb52006-01-08 01:02:45 -08001065
David Howellscab8eb52006-01-08 01:02:45 -08001066/*
David Howells973c9f42011-01-20 16:38:33 +00001067 * Preallocate memory so that a key can be linked into to a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068 */
David Howellsb2a4df22013-09-24 10:35:18 +01001069int __key_link_begin(struct key *keyring,
1070 const struct keyring_index_key *index_key,
1071 struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001072 __acquires(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001073 __acquires(&keyring_serialise_link_sem)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074{
David Howellsb2a4df22013-09-24 10:35:18 +01001075 struct assoc_array_edit *edit;
1076 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077
David Howells16feef42013-09-24 10:35:15 +01001078 kenter("%d,%s,%s,",
David Howellsb2a4df22013-09-24 10:35:18 +01001079 keyring->serial, index_key->type->name, index_key->description);
1080
1081 BUG_ON(index_key->desc_len == 0);
David Howellsf70e2e02010-04-30 14:32:39 +01001082
1083 if (keyring->type != &key_type_keyring)
1084 return -ENOTDIR;
1085
1086 down_write(&keyring->sem);
1087
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 ret = -EKEYREVOKED;
David Howells76d8aea2005-06-23 22:00:49 -07001089 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
David Howellsf70e2e02010-04-30 14:32:39 +01001090 goto error_krsem;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091
David Howellsf70e2e02010-04-30 14:32:39 +01001092 /* serialise link/link calls to prevent parallel calls causing a cycle
1093 * when linking two keyring in opposite orders */
David Howells16feef42013-09-24 10:35:15 +01001094 if (index_key->type == &key_type_keyring)
David Howells553d6032010-04-30 14:32:28 +01001095 down_write(&keyring_serialise_link_sem);
1096
David Howellsb2a4df22013-09-24 10:35:18 +01001097 /* Create an edit script that will insert/replace the key in the
1098 * keyring tree.
1099 */
1100 edit = assoc_array_insert(&keyring->keys,
1101 &keyring_assoc_array_ops,
1102 index_key,
1103 NULL);
1104 if (IS_ERR(edit)) {
1105 ret = PTR_ERR(edit);
David Howells034faeb2013-10-30 11:15:24 +00001106 goto error_sem;
1107 }
1108
1109 /* If we're not replacing a link in-place then we're going to need some
1110 * extra quota.
1111 */
1112 if (!edit->dead_leaf) {
1113 ret = key_payload_reserve(keyring,
1114 keyring->datalen + KEYQUOTA_LINK_BYTES);
1115 if (ret < 0)
1116 goto error_cancel;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 }
1118
David Howellsb2a4df22013-09-24 10:35:18 +01001119 *_edit = edit;
David Howellsf70e2e02010-04-30 14:32:39 +01001120 kleave(" = 0");
1121 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122
David Howells034faeb2013-10-30 11:15:24 +00001123error_cancel:
1124 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001125error_sem:
David Howells16feef42013-09-24 10:35:15 +01001126 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001127 up_write(&keyring_serialise_link_sem);
1128error_krsem:
1129 up_write(&keyring->sem);
1130 kleave(" = %d", ret);
1131 return ret;
1132}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
David Howellsf70e2e02010-04-30 14:32:39 +01001134/*
David Howells973c9f42011-01-20 16:38:33 +00001135 * Check already instantiated keys aren't going to be a problem.
1136 *
1137 * The caller must have called __key_link_begin(). Don't need to call this for
1138 * keys that were created since __key_link_begin() was called.
David Howellsf70e2e02010-04-30 14:32:39 +01001139 */
1140int __key_link_check_live_key(struct key *keyring, struct key *key)
1141{
1142 if (key->type == &key_type_keyring)
1143 /* check that we aren't going to create a cycle by linking one
1144 * keyring to another */
1145 return keyring_detect_cycle(keyring, key);
1146 return 0;
1147}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001148
David Howellsf70e2e02010-04-30 14:32:39 +01001149/*
David Howells973c9f42011-01-20 16:38:33 +00001150 * Link a key into to a keyring.
1151 *
1152 * Must be called with __key_link_begin() having being called. Discards any
1153 * already extant link to matching key if there is one, so that each keyring
1154 * holds at most one link to any given key of a particular type+description
1155 * combination.
David Howellsf70e2e02010-04-30 14:32:39 +01001156 */
David Howellsb2a4df22013-09-24 10:35:18 +01001157void __key_link(struct key *key, struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001158{
David Howellsccc3e6d2013-09-24 10:35:16 +01001159 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +01001160 assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key));
1161 assoc_array_apply_edit(*_edit);
1162 *_edit = NULL;
David Howellsf70e2e02010-04-30 14:32:39 +01001163}
1164
1165/*
David Howells973c9f42011-01-20 16:38:33 +00001166 * Finish linking a key into to a keyring.
1167 *
1168 * Must be called with __key_link_begin() having being called.
David Howellsf70e2e02010-04-30 14:32:39 +01001169 */
David Howells16feef42013-09-24 10:35:15 +01001170void __key_link_end(struct key *keyring,
1171 const struct keyring_index_key *index_key,
David Howellsb2a4df22013-09-24 10:35:18 +01001172 struct assoc_array_edit *edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001173 __releases(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001174 __releases(&keyring_serialise_link_sem)
David Howellsf70e2e02010-04-30 14:32:39 +01001175{
David Howells16feef42013-09-24 10:35:15 +01001176 BUG_ON(index_key->type == NULL);
David Howellsb2a4df22013-09-24 10:35:18 +01001177 kenter("%d,%s,", keyring->serial, index_key->type->name);
David Howellsf70e2e02010-04-30 14:32:39 +01001178
David Howells16feef42013-09-24 10:35:15 +01001179 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001180 up_write(&keyring_serialise_link_sem);
1181
David Howells034faeb2013-10-30 11:15:24 +00001182 if (edit && !edit->dead_leaf) {
David Howellsb2a4df22013-09-24 10:35:18 +01001183 key_payload_reserve(keyring,
1184 keyring->datalen - KEYQUOTA_LINK_BYTES);
1185 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001186 }
1187 up_write(&keyring->sem);
1188}
1189
David Howells973c9f42011-01-20 16:38:33 +00001190/**
1191 * key_link - Link a key to a keyring
1192 * @keyring: The keyring to make the link in.
1193 * @key: The key to link to.
1194 *
1195 * Make a link in a keyring to a key, such that the keyring holds a reference
1196 * on that key and the key can potentially be found by searching that keyring.
1197 *
1198 * This function will write-lock the keyring's semaphore and will consume some
1199 * of the user's key data quota to hold the link.
1200 *
1201 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
1202 * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
1203 * full, -EDQUOT if there is insufficient key data quota remaining to add
1204 * another link or -ENOMEM if there's insufficient memory.
1205 *
1206 * It is assumed that the caller has checked that it is permitted for a link to
1207 * be made (the keyring should have Write permission and the key Link
1208 * permission).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 */
1210int key_link(struct key *keyring, struct key *key)
1211{
David Howellsb2a4df22013-09-24 10:35:18 +01001212 struct assoc_array_edit *edit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 int ret;
1214
David Howellsb2a4df22013-09-24 10:35:18 +01001215 kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage));
1216
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 key_check(keyring);
1218 key_check(key);
1219
David Howells008643b2013-08-30 16:07:37 +01001220 if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) &&
1221 !test_bit(KEY_FLAG_TRUSTED, &key->flags))
1222 return -EPERM;
1223
David Howellsb2a4df22013-09-24 10:35:18 +01001224 ret = __key_link_begin(keyring, &key->index_key, &edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001225 if (ret == 0) {
David Howellsb2a4df22013-09-24 10:35:18 +01001226 kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));
David Howellsf70e2e02010-04-30 14:32:39 +01001227 ret = __key_link_check_live_key(keyring, key);
1228 if (ret == 0)
David Howellsb2a4df22013-09-24 10:35:18 +01001229 __key_link(key, &edit);
1230 __key_link_end(keyring, &key->index_key, edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001231 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001232
David Howellsb2a4df22013-09-24 10:35:18 +01001233 kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234 return ret;
David Howellsf70e2e02010-04-30 14:32:39 +01001235}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236EXPORT_SYMBOL(key_link);
1237
David Howells973c9f42011-01-20 16:38:33 +00001238/**
1239 * key_unlink - Unlink the first link to a key from a keyring.
1240 * @keyring: The keyring to remove the link from.
1241 * @key: The key the link is to.
1242 *
1243 * Remove a link from a keyring to a key.
1244 *
1245 * This function will write-lock the keyring's semaphore.
1246 *
1247 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
1248 * the key isn't linked to by the keyring or -ENOMEM if there's insufficient
1249 * memory.
1250 *
1251 * It is assumed that the caller has checked that it is permitted for a link to
1252 * be removed (the keyring should have Write permission; no permissions are
1253 * required on the key).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 */
1255int key_unlink(struct key *keyring, struct key *key)
1256{
David Howellsb2a4df22013-09-24 10:35:18 +01001257 struct assoc_array_edit *edit;
1258 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259
1260 key_check(keyring);
1261 key_check(key);
1262
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +01001264 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265
1266 down_write(&keyring->sem);
1267
David Howellsb2a4df22013-09-24 10:35:18 +01001268 edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
1269 &key->index_key);
1270 if (IS_ERR(edit)) {
1271 ret = PTR_ERR(edit);
1272 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 ret = -ENOENT;
David Howellsb2a4df22013-09-24 10:35:18 +01001275 if (edit == NULL)
1276 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277
David Howellsb2a4df22013-09-24 10:35:18 +01001278 assoc_array_apply_edit(edit);
David Howells034faeb2013-10-30 11:15:24 +00001279 key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 ret = 0;
1281
David Howells76d8aea2005-06-23 22:00:49 -07001282error:
David Howells76d8aea2005-06-23 22:00:49 -07001283 up_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001284 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001285}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286EXPORT_SYMBOL(key_unlink);
1287
David Howells973c9f42011-01-20 16:38:33 +00001288/**
1289 * keyring_clear - Clear a keyring
1290 * @keyring: The keyring to clear.
1291 *
1292 * Clear the contents of the specified keyring.
1293 *
1294 * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 */
1296int keyring_clear(struct key *keyring)
1297{
David Howellsb2a4df22013-09-24 10:35:18 +01001298 struct assoc_array_edit *edit;
David Howells76d8aea2005-06-23 22:00:49 -07001299 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300
David Howellsb2a4df22013-09-24 10:35:18 +01001301 if (keyring->type != &key_type_keyring)
1302 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303
David Howellsb2a4df22013-09-24 10:35:18 +01001304 down_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001305
David Howellsb2a4df22013-09-24 10:35:18 +01001306 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1307 if (IS_ERR(edit)) {
1308 ret = PTR_ERR(edit);
1309 } else {
1310 if (edit)
1311 assoc_array_apply_edit(edit);
1312 key_payload_reserve(keyring, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 ret = 0;
1314 }
1315
David Howellsb2a4df22013-09-24 10:35:18 +01001316 up_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001318}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319EXPORT_SYMBOL(keyring_clear);
David Howells31204ed2006-06-26 00:24:51 -07001320
David Howells31204ed2006-06-26 00:24:51 -07001321/*
David Howells973c9f42011-01-20 16:38:33 +00001322 * Dispose of the links from a revoked keyring.
1323 *
1324 * This is called with the key sem write-locked.
David Howells31204ed2006-06-26 00:24:51 -07001325 */
1326static void keyring_revoke(struct key *keyring)
1327{
David Howellsb2a4df22013-09-24 10:35:18 +01001328 struct assoc_array_edit *edit;
David Howellsf0641cb2010-04-30 14:32:18 +01001329
David Howellsb2a4df22013-09-24 10:35:18 +01001330 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1331 if (!IS_ERR(edit)) {
1332 if (edit)
1333 assoc_array_apply_edit(edit);
1334 key_payload_reserve(keyring, 0);
David Howells31204ed2006-06-26 00:24:51 -07001335 }
David Howellsa8b17ed2011-01-20 16:38:27 +00001336}
David Howells5d135442009-09-02 09:14:00 +01001337
David Howells62fe3182013-11-14 13:02:31 +00001338static bool keyring_gc_select_iterator(void *object, void *iterator_data)
David Howellsb2a4df22013-09-24 10:35:18 +01001339{
1340 struct key *key = keyring_ptr_to_key(object);
1341 time_t *limit = iterator_data;
1342
1343 if (key_is_dead(key, *limit))
1344 return false;
1345 key_get(key);
1346 return true;
1347}
1348
David Howells62fe3182013-11-14 13:02:31 +00001349static int keyring_gc_check_iterator(const void *object, void *iterator_data)
1350{
1351 const struct key *key = keyring_ptr_to_key(object);
1352 time_t *limit = iterator_data;
1353
1354 key_check(key);
1355 return key_is_dead(key, *limit);
1356}
1357
David Howells5d135442009-09-02 09:14:00 +01001358/*
David Howells62fe3182013-11-14 13:02:31 +00001359 * Garbage collect pointers from a keyring.
David Howells973c9f42011-01-20 16:38:33 +00001360 *
David Howells62fe3182013-11-14 13:02:31 +00001361 * Not called with any locks held. The keyring's key struct will not be
1362 * deallocated under us as only our caller may deallocate it.
David Howells5d135442009-09-02 09:14:00 +01001363 */
1364void keyring_gc(struct key *keyring, time_t limit)
1365{
David Howells62fe3182013-11-14 13:02:31 +00001366 int result;
David Howells5d135442009-09-02 09:14:00 +01001367
David Howells62fe3182013-11-14 13:02:31 +00001368 kenter("%x{%s}", keyring->serial, keyring->description ?: "");
1369
1370 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
1371 (1 << KEY_FLAG_REVOKED)))
1372 goto dont_gc;
1373
1374 /* scan the keyring looking for dead keys */
1375 rcu_read_lock();
1376 result = assoc_array_iterate(&keyring->keys,
1377 keyring_gc_check_iterator, &limit);
1378 rcu_read_unlock();
1379 if (result == true)
1380 goto do_gc;
1381
1382dont_gc:
1383 kleave(" [no gc]");
1384 return;
1385
1386do_gc:
David Howells5d135442009-09-02 09:14:00 +01001387 down_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001388 assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops,
David Howells62fe3182013-11-14 13:02:31 +00001389 keyring_gc_select_iterator, &limit);
David Howells5d135442009-09-02 09:14:00 +01001390 up_write(&keyring->sem);
David Howells62fe3182013-11-14 13:02:31 +00001391 kleave(" [gc]");
David Howells5d135442009-09-02 09:14:00 +01001392}