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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 */
76static int keyring_instantiate(struct key *keyring,
David Howellscf7f6012012-09-13 13:06:29 +010077 struct key_preparsed_payload *prep);
David Howells31204ed2006-06-26 00:24:51 -070078static void keyring_revoke(struct key *keyring);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079static void keyring_destroy(struct key *keyring);
80static void keyring_describe(const struct key *keyring, struct seq_file *m);
81static long keyring_read(const struct key *keyring,
82 char __user *buffer, size_t buflen);
83
84struct key_type key_type_keyring = {
85 .name = "keyring",
David Howellsb2a4df22013-09-24 10:35:18 +010086 .def_datalen = 0,
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 .instantiate = keyring_instantiate,
David Howellsb2a4df22013-09-24 10:35:18 +010088 .match = user_match,
David Howells31204ed2006-06-26 00:24:51 -070089 .revoke = keyring_revoke,
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 .destroy = keyring_destroy,
91 .describe = keyring_describe,
92 .read = keyring_read,
93};
David Howells73182262007-04-26 15:46:23 -070094EXPORT_SYMBOL(key_type_keyring);
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096/*
David Howells973c9f42011-01-20 16:38:33 +000097 * Semaphore to serialise link/link calls to prevent two link calls in parallel
98 * introducing a cycle.
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 */
Adrian Bunk1ae8f402006-01-06 00:11:25 -0800100static DECLARE_RWSEM(keyring_serialise_link_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102/*
David Howells973c9f42011-01-20 16:38:33 +0000103 * Publish the name of a keyring so that it can be found by name (if it has
104 * one).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 */
David Howells69664cf2008-04-29 01:01:31 -0700106static void keyring_publish_name(struct key *keyring)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
108 int bucket;
109
110 if (keyring->description) {
111 bucket = keyring_hash(keyring->description);
112
113 write_lock(&keyring_name_lock);
114
115 if (!keyring_name_hash[bucket].next)
116 INIT_LIST_HEAD(&keyring_name_hash[bucket]);
117
118 list_add_tail(&keyring->type_data.link,
119 &keyring_name_hash[bucket]);
120
121 write_unlock(&keyring_name_lock);
122 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000123}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125/*
David Howells973c9f42011-01-20 16:38:33 +0000126 * Initialise a keyring.
127 *
128 * Returns 0 on success, -EINVAL if given any data.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 */
130static int keyring_instantiate(struct key *keyring,
David Howellscf7f6012012-09-13 13:06:29 +0100131 struct key_preparsed_payload *prep)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132{
133 int ret;
134
135 ret = -EINVAL;
David Howellscf7f6012012-09-13 13:06:29 +0100136 if (prep->datalen == 0) {
David Howellsb2a4df22013-09-24 10:35:18 +0100137 assoc_array_init(&keyring->keys);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 /* make the keyring available by name if it has one */
139 keyring_publish_name(keyring);
140 ret = 0;
141 }
142
143 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +0000144}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146/*
David Howellsb2a4df22013-09-24 10:35:18 +0100147 * Multiply 64-bits by 32-bits to 96-bits and fold back to 64-bit. Ideally we'd
148 * fold the carry back too, but that requires inline asm.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 */
David Howellsb2a4df22013-09-24 10:35:18 +0100150static u64 mult_64x32_and_fold(u64 x, u32 y)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151{
David Howellsb2a4df22013-09-24 10:35:18 +0100152 u64 hi = (u64)(u32)(x >> 32) * y;
153 u64 lo = (u64)(u32)(x) * y;
154 return lo + ((u64)(u32)hi << 32) + (u32)(hi >> 32);
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 * Hash a key type and description.
159 */
160static unsigned long hash_key_type_and_desc(const struct keyring_index_key *index_key)
161{
162 const unsigned level_shift = ASSOC_ARRAY_LEVEL_STEP;
David Howellsd54e58b2013-12-02 11:24:18 +0000163 const unsigned long fan_mask = ASSOC_ARRAY_FAN_MASK;
David Howellsb2a4df22013-09-24 10:35:18 +0100164 const char *description = index_key->description;
165 unsigned long hash, type;
166 u32 piece;
167 u64 acc;
168 int n, desc_len = index_key->desc_len;
169
170 type = (unsigned long)index_key->type;
171
172 acc = mult_64x32_and_fold(type, desc_len + 13);
173 acc = mult_64x32_and_fold(acc, 9207);
174 for (;;) {
175 n = desc_len;
176 if (n <= 0)
177 break;
178 if (n > 4)
179 n = 4;
180 piece = 0;
181 memcpy(&piece, description, n);
182 description += n;
183 desc_len -= n;
184 acc = mult_64x32_and_fold(acc, piece);
185 acc = mult_64x32_and_fold(acc, 9207);
186 }
187
188 /* Fold the hash down to 32 bits if need be. */
189 hash = acc;
190 if (ASSOC_ARRAY_KEY_CHUNK_SIZE == 32)
191 hash ^= acc >> 32;
192
193 /* Squidge all the keyrings into a separate part of the tree to
194 * ordinary keys by making sure the lowest level segment in the hash is
195 * zero for keyrings and non-zero otherwise.
196 */
David Howellsd54e58b2013-12-02 11:24:18 +0000197 if (index_key->type != &key_type_keyring && (hash & fan_mask) == 0)
David Howellsb2a4df22013-09-24 10:35:18 +0100198 return hash | (hash >> (ASSOC_ARRAY_KEY_CHUNK_SIZE - level_shift)) | 1;
David Howellsd54e58b2013-12-02 11:24:18 +0000199 if (index_key->type == &key_type_keyring && (hash & fan_mask) != 0)
200 return (hash + (hash << level_shift)) & ~fan_mask;
David Howellsb2a4df22013-09-24 10:35:18 +0100201 return hash;
202}
203
204/*
205 * Build the next index key chunk.
206 *
207 * On 32-bit systems the index key is laid out as:
208 *
209 * 0 4 5 9...
210 * hash desclen typeptr desc[]
211 *
212 * On 64-bit systems:
213 *
214 * 0 8 9 17...
215 * hash desclen typeptr desc[]
216 *
217 * We return it one word-sized chunk at a time.
218 */
219static unsigned long keyring_get_key_chunk(const void *data, int level)
220{
221 const struct keyring_index_key *index_key = data;
222 unsigned long chunk = 0;
223 long offset = 0;
224 int desc_len = index_key->desc_len, n = sizeof(chunk);
225
226 level /= ASSOC_ARRAY_KEY_CHUNK_SIZE;
227 switch (level) {
228 case 0:
229 return hash_key_type_and_desc(index_key);
230 case 1:
231 return ((unsigned long)index_key->type << 8) | desc_len;
232 case 2:
233 if (desc_len == 0)
234 return (u8)((unsigned long)index_key->type >>
235 (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
236 n--;
237 offset = 1;
238 default:
239 offset += sizeof(chunk) - 1;
240 offset += (level - 3) * sizeof(chunk);
241 if (offset >= desc_len)
242 return 0;
243 desc_len -= offset;
244 if (desc_len > n)
245 desc_len = n;
246 offset += desc_len;
247 do {
248 chunk <<= 8;
249 chunk |= ((u8*)index_key->description)[--offset];
250 } while (--desc_len > 0);
251
252 if (level == 2) {
253 chunk <<= 8;
254 chunk |= (u8)((unsigned long)index_key->type >>
255 (ASSOC_ARRAY_KEY_CHUNK_SIZE - 8));
256 }
257 return chunk;
258 }
259}
260
261static unsigned long keyring_get_object_key_chunk(const void *object, int level)
262{
263 const struct key *key = keyring_ptr_to_key(object);
264 return keyring_get_key_chunk(&key->index_key, level);
265}
266
267static bool keyring_compare_object(const void *object, const void *data)
268{
269 const struct keyring_index_key *index_key = data;
270 const struct key *key = keyring_ptr_to_key(object);
271
272 return key->index_key.type == index_key->type &&
273 key->index_key.desc_len == index_key->desc_len &&
274 memcmp(key->index_key.description, index_key->description,
275 index_key->desc_len) == 0;
276}
277
278/*
279 * Compare the index keys of a pair of objects and determine the bit position
280 * at which they differ - if they differ.
281 */
David Howells23fd78d2013-12-02 11:24:18 +0000282static int keyring_diff_objects(const void *object, const void *data)
David Howellsb2a4df22013-09-24 10:35:18 +0100283{
David Howells23fd78d2013-12-02 11:24:18 +0000284 const struct key *key_a = keyring_ptr_to_key(object);
David Howellsb2a4df22013-09-24 10:35:18 +0100285 const struct keyring_index_key *a = &key_a->index_key;
David Howells23fd78d2013-12-02 11:24:18 +0000286 const struct keyring_index_key *b = data;
David Howellsb2a4df22013-09-24 10:35:18 +0100287 unsigned long seg_a, seg_b;
288 int level, i;
289
290 level = 0;
291 seg_a = hash_key_type_and_desc(a);
292 seg_b = hash_key_type_and_desc(b);
293 if ((seg_a ^ seg_b) != 0)
294 goto differ;
295
296 /* The number of bits contributed by the hash is controlled by a
297 * constant in the assoc_array headers. Everything else thereafter we
298 * can deal with as being machine word-size dependent.
299 */
300 level += ASSOC_ARRAY_KEY_CHUNK_SIZE / 8;
301 seg_a = a->desc_len;
302 seg_b = b->desc_len;
303 if ((seg_a ^ seg_b) != 0)
304 goto differ;
305
306 /* The next bit may not work on big endian */
307 level++;
308 seg_a = (unsigned long)a->type;
309 seg_b = (unsigned long)b->type;
310 if ((seg_a ^ seg_b) != 0)
311 goto differ;
312
313 level += sizeof(unsigned long);
314 if (a->desc_len == 0)
315 goto same;
316
317 i = 0;
318 if (((unsigned long)a->description | (unsigned long)b->description) &
319 (sizeof(unsigned long) - 1)) {
320 do {
321 seg_a = *(unsigned long *)(a->description + i);
322 seg_b = *(unsigned long *)(b->description + i);
323 if ((seg_a ^ seg_b) != 0)
324 goto differ_plus_i;
325 i += sizeof(unsigned long);
326 } while (i < (a->desc_len & (sizeof(unsigned long) - 1)));
327 }
328
329 for (; i < a->desc_len; i++) {
330 seg_a = *(unsigned char *)(a->description + i);
331 seg_b = *(unsigned char *)(b->description + i);
332 if ((seg_a ^ seg_b) != 0)
333 goto differ_plus_i;
334 }
335
336same:
337 return -1;
338
339differ_plus_i:
340 level += i;
341differ:
342 i = level * 8 + __ffs(seg_a ^ seg_b);
343 return i;
344}
345
346/*
347 * Free an object after stripping the keyring flag off of the pointer.
348 */
349static void keyring_free_object(void *object)
350{
351 key_put(keyring_ptr_to_key(object));
352}
353
354/*
355 * Operations for keyring management by the index-tree routines.
356 */
357static const struct assoc_array_ops keyring_assoc_array_ops = {
358 .get_key_chunk = keyring_get_key_chunk,
359 .get_object_key_chunk = keyring_get_object_key_chunk,
360 .compare_object = keyring_compare_object,
361 .diff_objects = keyring_diff_objects,
362 .free_object = keyring_free_object,
363};
364
365/*
David Howells973c9f42011-01-20 16:38:33 +0000366 * Clean up a keyring when it is destroyed. Unpublish its name if it had one
367 * and dispose of its data.
David Howells233e4732012-05-11 10:56:56 +0100368 *
369 * The garbage collector detects the final key_put(), removes the keyring from
370 * the serial number tree and then does RCU synchronisation before coming here,
371 * so we shouldn't need to worry about code poking around here with the RCU
372 * readlock held by this time.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 */
374static void keyring_destroy(struct key *keyring)
375{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 if (keyring->description) {
377 write_lock(&keyring_name_lock);
David Howells94efe722005-08-04 13:07:07 -0700378
379 if (keyring->type_data.link.next != NULL &&
380 !list_empty(&keyring->type_data.link))
381 list_del(&keyring->type_data.link);
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 write_unlock(&keyring_name_lock);
384 }
385
David Howellsb2a4df22013-09-24 10:35:18 +0100386 assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops);
David Howellsa8b17ed2011-01-20 16:38:27 +0000387}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389/*
David Howells973c9f42011-01-20 16:38:33 +0000390 * Describe a keyring for /proc.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 */
392static void keyring_describe(const struct key *keyring, struct seq_file *m)
393{
wzt.wzt@gmail.comc8563472010-03-04 21:26:23 +0800394 if (keyring->description)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 seq_puts(m, keyring->description);
wzt.wzt@gmail.comc8563472010-03-04 21:26:23 +0800396 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700397 seq_puts(m, "[anon]");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398
David Howells78b72802011-03-11 17:57:23 +0000399 if (key_is_instantiated(keyring)) {
David Howellsb2a4df22013-09-24 10:35:18 +0100400 if (keyring->keys.nr_leaves_on_tree != 0)
401 seq_printf(m, ": %lu", keyring->keys.nr_leaves_on_tree);
David Howells78b72802011-03-11 17:57:23 +0000402 else
403 seq_puts(m, ": empty");
David Howells78b72802011-03-11 17:57:23 +0000404 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000405}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406
David Howellsb2a4df22013-09-24 10:35:18 +0100407struct keyring_read_iterator_context {
408 size_t qty;
409 size_t count;
410 key_serial_t __user *buffer;
411};
412
413static int keyring_read_iterator(const void *object, void *data)
414{
415 struct keyring_read_iterator_context *ctx = data;
416 const struct key *key = keyring_ptr_to_key(object);
417 int ret;
418
419 kenter("{%s,%d},,{%zu/%zu}",
420 key->type->name, key->serial, ctx->count, ctx->qty);
421
422 if (ctx->count >= ctx->qty)
423 return 1;
424
425 ret = put_user(key->serial, ctx->buffer);
426 if (ret < 0)
427 return ret;
428 ctx->buffer++;
429 ctx->count += sizeof(key->serial);
430 return 0;
431}
432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433/*
David Howells973c9f42011-01-20 16:38:33 +0000434 * Read a list of key IDs from the keyring's contents in binary form
435 *
David Howellsb2a4df22013-09-24 10:35:18 +0100436 * The keyring's semaphore is read-locked by the caller. This prevents someone
437 * from modifying it under us - which could cause us to read key IDs multiple
438 * times.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 */
440static long keyring_read(const struct key *keyring,
441 char __user *buffer, size_t buflen)
442{
David Howellsb2a4df22013-09-24 10:35:18 +0100443 struct keyring_read_iterator_context ctx;
444 unsigned long nr_keys;
445 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
David Howellsb2a4df22013-09-24 10:35:18 +0100447 kenter("{%d},,%zu", key_serial(keyring), buflen);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
David Howellsb2a4df22013-09-24 10:35:18 +0100449 if (buflen & (sizeof(key_serial_t) - 1))
450 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451
David Howellsb2a4df22013-09-24 10:35:18 +0100452 nr_keys = keyring->keys.nr_leaves_on_tree;
453 if (nr_keys == 0)
454 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
David Howellsb2a4df22013-09-24 10:35:18 +0100456 /* Calculate how much data we could return */
457 ctx.qty = nr_keys * sizeof(key_serial_t);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
David Howellsb2a4df22013-09-24 10:35:18 +0100459 if (!buffer || !buflen)
460 return ctx.qty;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461
David Howellsb2a4df22013-09-24 10:35:18 +0100462 if (buflen > ctx.qty)
463 ctx.qty = buflen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
David Howellsb2a4df22013-09-24 10:35:18 +0100465 /* Copy the IDs of the subscribed keys into the buffer */
466 ctx.buffer = (key_serial_t __user *)buffer;
467 ctx.count = 0;
468 ret = assoc_array_iterate(&keyring->keys, keyring_read_iterator, &ctx);
469 if (ret < 0) {
470 kleave(" = %d [iterate]", ret);
471 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 }
473
David Howellsb2a4df22013-09-24 10:35:18 +0100474 kleave(" = %zu [ok]", ctx.count);
475 return ctx.count;
David Howellsa8b17ed2011-01-20 16:38:27 +0000476}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478/*
David Howells973c9f42011-01-20 16:38:33 +0000479 * Allocate a keyring and link into the destination keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 */
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800481struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
David Howells96b5c8f2012-10-02 19:24:56 +0100482 const struct cred *cred, key_perm_t perm,
483 unsigned long flags, struct key *dest)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484{
485 struct key *keyring;
486 int ret;
487
488 keyring = key_alloc(&key_type_keyring, description,
David Howells96b5c8f2012-10-02 19:24:56 +0100489 uid, gid, cred, perm, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 if (!IS_ERR(keyring)) {
David Howells3e301482005-06-23 22:00:56 -0700491 ret = key_instantiate_and_link(keyring, NULL, 0, dest, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 if (ret < 0) {
493 key_put(keyring);
494 keyring = ERR_PTR(ret);
495 }
496 }
497
498 return keyring;
David Howellsa8b17ed2011-01-20 16:38:27 +0000499}
David Howellsf8aa23a2012-10-02 19:24:56 +0100500EXPORT_SYMBOL(keyring_alloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
David Howellsb2a4df22013-09-24 10:35:18 +0100502/*
503 * Iteration function to consider each key found.
504 */
505static int keyring_search_iterator(const void *object, void *iterator_data)
506{
507 struct keyring_search_context *ctx = iterator_data;
508 const struct key *key = keyring_ptr_to_key(object);
509 unsigned long kflags = key->flags;
510
511 kenter("{%d}", key->serial);
512
513 /* ignore keys not of this type */
514 if (key->type != ctx->index_key.type) {
515 kleave(" = 0 [!type]");
516 return 0;
517 }
518
519 /* skip invalidated, revoked and expired keys */
520 if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
521 if (kflags & ((1 << KEY_FLAG_INVALIDATED) |
522 (1 << KEY_FLAG_REVOKED))) {
523 ctx->result = ERR_PTR(-EKEYREVOKED);
524 kleave(" = %d [invrev]", ctx->skipped_ret);
525 goto skipped;
526 }
527
528 if (key->expiry && ctx->now.tv_sec >= key->expiry) {
529 ctx->result = ERR_PTR(-EKEYEXPIRED);
530 kleave(" = %d [expire]", ctx->skipped_ret);
531 goto skipped;
532 }
533 }
534
535 /* keys that don't match */
536 if (!ctx->match(key, ctx->match_data)) {
537 kleave(" = 0 [!match]");
538 return 0;
539 }
540
541 /* key must have search permissions */
542 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
543 key_task_permission(make_key_ref(key, ctx->possessed),
544 ctx->cred, KEY_SEARCH) < 0) {
545 ctx->result = ERR_PTR(-EACCES);
546 kleave(" = %d [!perm]", ctx->skipped_ret);
547 goto skipped;
548 }
549
550 if (ctx->flags & KEYRING_SEARCH_DO_STATE_CHECK) {
551 /* we set a different error code if we pass a negative key */
552 if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
David Howells74792b02013-10-30 11:15:24 +0000553 smp_rmb();
David Howellsb2a4df22013-09-24 10:35:18 +0100554 ctx->result = ERR_PTR(key->type_data.reject_error);
555 kleave(" = %d [neg]", ctx->skipped_ret);
556 goto skipped;
557 }
558 }
559
560 /* Found */
561 ctx->result = make_key_ref(key, ctx->possessed);
562 kleave(" = 1 [found]");
563 return 1;
564
565skipped:
566 return ctx->skipped_ret;
567}
568
569/*
570 * Search inside a keyring for a key. We can search by walking to it
571 * directly based on its index-key or we can iterate over the entire
572 * tree looking for it, based on the match function.
573 */
574static int search_keyring(struct key *keyring, struct keyring_search_context *ctx)
575{
576 if ((ctx->flags & KEYRING_SEARCH_LOOKUP_TYPE) ==
577 KEYRING_SEARCH_LOOKUP_DIRECT) {
578 const void *object;
579
580 object = assoc_array_find(&keyring->keys,
581 &keyring_assoc_array_ops,
582 &ctx->index_key);
583 return object ? ctx->iterator(object, ctx) : 0;
584 }
585 return assoc_array_iterate(&keyring->keys, ctx->iterator, ctx);
586}
587
588/*
589 * Search a tree of keyrings that point to other keyrings up to the maximum
590 * depth.
591 */
592static bool search_nested_keyrings(struct key *keyring,
593 struct keyring_search_context *ctx)
594{
595 struct {
596 struct key *keyring;
597 struct assoc_array_node *node;
598 int slot;
599 } stack[KEYRING_SEARCH_MAX_DEPTH];
600
601 struct assoc_array_shortcut *shortcut;
602 struct assoc_array_node *node;
603 struct assoc_array_ptr *ptr;
604 struct key *key;
605 int sp = 0, slot;
606
607 kenter("{%d},{%s,%s}",
608 keyring->serial,
609 ctx->index_key.type->name,
610 ctx->index_key.description);
611
612 if (ctx->index_key.description)
613 ctx->index_key.desc_len = strlen(ctx->index_key.description);
614
615 /* Check to see if this top-level keyring is what we are looking for
616 * and whether it is valid or not.
617 */
618 if (ctx->flags & KEYRING_SEARCH_LOOKUP_ITERATE ||
619 keyring_compare_object(keyring, &ctx->index_key)) {
620 ctx->skipped_ret = 2;
621 ctx->flags |= KEYRING_SEARCH_DO_STATE_CHECK;
622 switch (ctx->iterator(keyring_key_to_ptr(keyring), ctx)) {
623 case 1:
624 goto found;
625 case 2:
626 return false;
627 default:
628 break;
629 }
630 }
631
632 ctx->skipped_ret = 0;
633 if (ctx->flags & KEYRING_SEARCH_NO_STATE_CHECK)
634 ctx->flags &= ~KEYRING_SEARCH_DO_STATE_CHECK;
635
636 /* Start processing a new keyring */
637descend_to_keyring:
638 kdebug("descend to %d", keyring->serial);
639 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
640 (1 << KEY_FLAG_REVOKED)))
641 goto not_this_keyring;
642
643 /* Search through the keys in this keyring before its searching its
644 * subtrees.
645 */
646 if (search_keyring(keyring, ctx))
647 goto found;
648
649 /* Then manually iterate through the keyrings nested in this one.
650 *
651 * Start from the root node of the index tree. Because of the way the
652 * hash function has been set up, keyrings cluster on the leftmost
653 * branch of the root node (root slot 0) or in the root node itself.
654 * Non-keyrings avoid the leftmost branch of the root entirely (root
655 * slots 1-15).
656 */
657 ptr = ACCESS_ONCE(keyring->keys.root);
658 if (!ptr)
659 goto not_this_keyring;
660
661 if (assoc_array_ptr_is_shortcut(ptr)) {
662 /* If the root is a shortcut, either the keyring only contains
663 * keyring pointers (everything clusters behind root slot 0) or
664 * doesn't contain any keyring pointers.
665 */
666 shortcut = assoc_array_ptr_to_shortcut(ptr);
667 smp_read_barrier_depends();
668 if ((shortcut->index_key[0] & ASSOC_ARRAY_FAN_MASK) != 0)
669 goto not_this_keyring;
670
671 ptr = ACCESS_ONCE(shortcut->next_node);
672 node = assoc_array_ptr_to_node(ptr);
673 goto begin_node;
674 }
675
676 node = assoc_array_ptr_to_node(ptr);
677 smp_read_barrier_depends();
678
679 ptr = node->slots[0];
680 if (!assoc_array_ptr_is_meta(ptr))
681 goto begin_node;
682
683descend_to_node:
684 /* Descend to a more distal node in this keyring's content tree and go
685 * through that.
686 */
687 kdebug("descend");
688 if (assoc_array_ptr_is_shortcut(ptr)) {
689 shortcut = assoc_array_ptr_to_shortcut(ptr);
690 smp_read_barrier_depends();
691 ptr = ACCESS_ONCE(shortcut->next_node);
692 BUG_ON(!assoc_array_ptr_is_node(ptr));
David Howellsb2a4df22013-09-24 10:35:18 +0100693 }
David Howells9c5e45d2013-12-02 11:24:19 +0000694 node = assoc_array_ptr_to_node(ptr);
David Howellsb2a4df22013-09-24 10:35:18 +0100695
696begin_node:
697 kdebug("begin_node");
698 smp_read_barrier_depends();
699 slot = 0;
700ascend_to_node:
701 /* Go through the slots in a node */
702 for (; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
703 ptr = ACCESS_ONCE(node->slots[slot]);
704
705 if (assoc_array_ptr_is_meta(ptr) && node->back_pointer)
706 goto descend_to_node;
707
708 if (!keyring_ptr_is_keyring(ptr))
709 continue;
710
711 key = keyring_ptr_to_key(ptr);
712
713 if (sp >= KEYRING_SEARCH_MAX_DEPTH) {
714 if (ctx->flags & KEYRING_SEARCH_DETECT_TOO_DEEP) {
715 ctx->result = ERR_PTR(-ELOOP);
716 return false;
717 }
718 goto not_this_keyring;
719 }
720
721 /* Search a nested keyring */
722 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM) &&
723 key_task_permission(make_key_ref(key, ctx->possessed),
724 ctx->cred, KEY_SEARCH) < 0)
725 continue;
726
727 /* stack the current position */
728 stack[sp].keyring = keyring;
729 stack[sp].node = node;
730 stack[sp].slot = slot;
731 sp++;
732
733 /* begin again with the new keyring */
734 keyring = key;
735 goto descend_to_keyring;
736 }
737
738 /* We've dealt with all the slots in the current node, so now we need
739 * to ascend to the parent and continue processing there.
740 */
741 ptr = ACCESS_ONCE(node->back_pointer);
742 slot = node->parent_slot;
743
744 if (ptr && assoc_array_ptr_is_shortcut(ptr)) {
745 shortcut = assoc_array_ptr_to_shortcut(ptr);
746 smp_read_barrier_depends();
747 ptr = ACCESS_ONCE(shortcut->back_pointer);
748 slot = shortcut->parent_slot;
749 }
750 if (!ptr)
751 goto not_this_keyring;
752 node = assoc_array_ptr_to_node(ptr);
753 smp_read_barrier_depends();
754 slot++;
755
756 /* If we've ascended to the root (zero backpointer), we must have just
757 * finished processing the leftmost branch rather than the root slots -
758 * so there can't be any more keyrings for us to find.
759 */
760 if (node->back_pointer) {
761 kdebug("ascend %d", slot);
762 goto ascend_to_node;
763 }
764
765 /* The keyring we're looking at was disqualified or didn't contain a
766 * matching key.
767 */
768not_this_keyring:
769 kdebug("not_this_keyring %d", sp);
770 if (sp <= 0) {
771 kleave(" = false");
772 return false;
773 }
774
775 /* Resume the processing of a keyring higher up in the tree */
776 sp--;
777 keyring = stack[sp].keyring;
778 node = stack[sp].node;
779 slot = stack[sp].slot + 1;
780 kdebug("ascend to %d [%d]", keyring->serial, slot);
781 goto ascend_to_node;
782
783 /* We found a viable match */
784found:
785 key = key_ref_to_ptr(ctx->result);
786 key_check(key);
787 if (!(ctx->flags & KEYRING_SEARCH_NO_UPDATE_TIME)) {
788 key->last_used_at = ctx->now.tv_sec;
789 keyring->last_used_at = ctx->now.tv_sec;
790 while (sp > 0)
791 stack[--sp].keyring->last_used_at = ctx->now.tv_sec;
792 }
793 kleave(" = true");
794 return true;
795}
796
David Howells973c9f42011-01-20 16:38:33 +0000797/**
798 * keyring_search_aux - Search a keyring tree for a key matching some criteria
799 * @keyring_ref: A pointer to the keyring with possession indicator.
David Howells4bdf0bc2013-09-24 10:35:15 +0100800 * @ctx: The keyring search context.
David Howells973c9f42011-01-20 16:38:33 +0000801 *
802 * Search the supplied keyring tree for a key that matches the criteria given.
803 * The root keyring and any linked keyrings must grant Search permission to the
804 * caller to be searchable and keys can only be found if they too grant Search
805 * to the caller. The possession flag on the root keyring pointer controls use
806 * of the possessor bits in permissions checking of the entire tree. In
807 * addition, the LSM gets to forbid keyring searches and key matches.
808 *
809 * The search is performed as a breadth-then-depth search up to the prescribed
810 * limit (KEYRING_SEARCH_MAX_DEPTH).
811 *
812 * Keys are matched to the type provided and are then filtered by the match
813 * function, which is given the description to use in any way it sees fit. The
814 * match function may use any attributes of a key that it wishes to to
815 * determine the match. Normally the match function from the key type would be
816 * used.
817 *
David Howellsb2a4df22013-09-24 10:35:18 +0100818 * RCU can be used to prevent the keyring key lists from disappearing without
819 * the need to take lots of locks.
David Howells973c9f42011-01-20 16:38:33 +0000820 *
821 * Returns a pointer to the found key and increments the key usage count if
822 * successful; -EAGAIN if no matching keys were found, or if expired or revoked
823 * keys were found; -ENOKEY if only negative keys were found; -ENOTDIR if the
824 * specified keyring wasn't a keyring.
825 *
826 * In the case of a successful return, the possession attribute from
827 * @keyring_ref is propagated to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 */
David Howells664cceb2005-09-28 17:03:15 +0100829key_ref_t keyring_search_aux(key_ref_t keyring_ref,
David Howells4bdf0bc2013-09-24 10:35:15 +0100830 struct keyring_search_context *ctx)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831{
David Howellsb2a4df22013-09-24 10:35:18 +0100832 struct key *keyring;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 long err;
David Howellsb2a4df22013-09-24 10:35:18 +0100834
835 ctx->iterator = keyring_search_iterator;
836 ctx->possessed = is_key_possessed(keyring_ref);
837 ctx->result = ERR_PTR(-EAGAIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
David Howells664cceb2005-09-28 17:03:15 +0100839 keyring = key_ref_to_ptr(keyring_ref);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840 key_check(keyring);
841
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +0100843 return ERR_PTR(-ENOTDIR);
844
845 if (!(ctx->flags & KEYRING_SEARCH_NO_CHECK_PERM)) {
846 err = key_task_permission(keyring_ref, ctx->cred, KEY_SEARCH);
847 if (err < 0)
848 return ERR_PTR(err);
849 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
David Howells664cceb2005-09-28 17:03:15 +0100851 rcu_read_lock();
David Howells4bdf0bc2013-09-24 10:35:15 +0100852 ctx->now = current_kernel_time();
David Howellsb2a4df22013-09-24 10:35:18 +0100853 if (search_nested_keyrings(keyring, ctx))
854 __key_get(key_ref_to_ptr(ctx->result));
David Howells76d8aea2005-06-23 22:00:49 -0700855 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +0100856 return ctx->result;
David Howellsa8b17ed2011-01-20 16:38:27 +0000857}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858
David Howells973c9f42011-01-20 16:38:33 +0000859/**
860 * keyring_search - Search the supplied keyring tree for a matching key
861 * @keyring: The root of the keyring tree to be searched.
862 * @type: The type of keyring we want to find.
863 * @description: The name of the keyring we want to find.
864 *
865 * As keyring_search_aux() above, but using the current task's credentials and
David Howellsb2a4df22013-09-24 10:35:18 +0100866 * type's default matching function and preferred search method.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 */
David Howells664cceb2005-09-28 17:03:15 +0100868key_ref_t keyring_search(key_ref_t keyring,
869 struct key_type *type,
870 const char *description)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871{
David Howells4bdf0bc2013-09-24 10:35:15 +0100872 struct keyring_search_context ctx = {
873 .index_key.type = type,
874 .index_key.description = description,
875 .cred = current_cred(),
876 .match = type->match,
877 .match_data = description,
878 .flags = (type->def_lookup_type |
879 KEYRING_SEARCH_DO_STATE_CHECK),
880 };
881
882 if (!ctx.match)
David Howells3e301482005-06-23 22:00:56 -0700883 return ERR_PTR(-ENOKEY);
884
David Howells4bdf0bc2013-09-24 10:35:15 +0100885 return keyring_search_aux(keyring, &ctx);
David Howellsa8b17ed2011-01-20 16:38:27 +0000886}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887EXPORT_SYMBOL(keyring_search);
888
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889/*
David Howellsb2a4df22013-09-24 10:35:18 +0100890 * Search the given keyring for a key that might be updated.
David Howells973c9f42011-01-20 16:38:33 +0000891 *
892 * The caller must guarantee that the keyring is a keyring and that the
David Howellsb2a4df22013-09-24 10:35:18 +0100893 * permission is granted to modify the keyring as no check is made here. The
894 * caller must also hold a lock on the keyring semaphore.
David Howells973c9f42011-01-20 16:38:33 +0000895 *
896 * Returns a pointer to the found key with usage count incremented if
David Howellsb2a4df22013-09-24 10:35:18 +0100897 * successful and returns NULL if not found. Revoked and invalidated keys are
898 * skipped over.
David Howells973c9f42011-01-20 16:38:33 +0000899 *
900 * If successful, the possession indicator is propagated from the keyring ref
901 * to the returned key reference.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 */
David Howellsb2a4df22013-09-24 10:35:18 +0100903key_ref_t find_key_to_update(key_ref_t keyring_ref,
904 const struct keyring_index_key *index_key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905{
David Howells664cceb2005-09-28 17:03:15 +0100906 struct key *keyring, *key;
David Howellsb2a4df22013-09-24 10:35:18 +0100907 const void *object;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908
David Howells664cceb2005-09-28 17:03:15 +0100909 keyring = key_ref_to_ptr(keyring_ref);
David Howells664cceb2005-09-28 17:03:15 +0100910
David Howellsb2a4df22013-09-24 10:35:18 +0100911 kenter("{%d},{%s,%s}",
912 keyring->serial, index_key->type->name, index_key->description);
David Howells76d8aea2005-06-23 22:00:49 -0700913
David Howellsb2a4df22013-09-24 10:35:18 +0100914 object = assoc_array_find(&keyring->keys, &keyring_assoc_array_ops,
915 index_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916
David Howellsb2a4df22013-09-24 10:35:18 +0100917 if (object)
918 goto found;
919
920 kleave(" = NULL");
921 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
Justin P. Mattockc5b60b52010-04-21 00:02:11 -0700923found:
David Howellsb2a4df22013-09-24 10:35:18 +0100924 key = keyring_ptr_to_key(object);
925 if (key->flags & ((1 << KEY_FLAG_INVALIDATED) |
926 (1 << KEY_FLAG_REVOKED))) {
927 kleave(" = NULL [x]");
928 return NULL;
929 }
David Howellsccc3e6d2013-09-24 10:35:16 +0100930 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +0100931 kleave(" = {%d}", key->serial);
932 return make_key_ref(key, is_key_possessed(keyring_ref));
David Howellsa8b17ed2011-01-20 16:38:27 +0000933}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935/*
David Howells973c9f42011-01-20 16:38:33 +0000936 * Find a keyring with the specified name.
937 *
938 * All named keyrings in the current user namespace are searched, provided they
939 * grant Search permission directly to the caller (unless this check is
940 * skipped). Keyrings whose usage points have reached zero or who have been
941 * revoked are skipped.
942 *
943 * Returns a pointer to the keyring with the keyring's refcount having being
944 * incremented on success. -ENOKEY is returned if a key could not be found.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 */
David Howells69664cf2008-04-29 01:01:31 -0700946struct key *find_keyring_by_name(const char *name, bool skip_perm_check)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947{
948 struct key *keyring;
949 int bucket;
950
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 if (!name)
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100952 return ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953
954 bucket = keyring_hash(name);
955
956 read_lock(&keyring_name_lock);
957
958 if (keyring_name_hash[bucket].next) {
959 /* search this hash bucket for a keyring with a matching name
960 * that's readable and that hasn't been revoked */
961 list_for_each_entry(keyring,
962 &keyring_name_hash[bucket],
963 type_data.link
964 ) {
Eric W. Biederman9a56c2d2012-02-08 07:53:04 -0800965 if (!kuid_has_mapping(current_user_ns(), keyring->user->uid))
Serge E. Hallyn2ea190d2009-02-26 18:27:55 -0600966 continue;
967
David Howells76d8aea2005-06-23 22:00:49 -0700968 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 continue;
970
971 if (strcmp(keyring->description, name) != 0)
972 continue;
973
David Howells69664cf2008-04-29 01:01:31 -0700974 if (!skip_perm_check &&
975 key_permission(make_key_ref(keyring, 0),
David Howells0f6ed7c2005-11-07 00:59:30 -0800976 KEY_SEARCH) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 continue;
978
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100979 /* we've got a match but we might end up racing with
980 * key_cleanup() if the keyring is currently 'dead'
981 * (ie. it has a zero usage count) */
982 if (!atomic_inc_not_zero(&keyring->usage))
983 continue;
David Howells31d5a792012-05-11 10:56:56 +0100984 keyring->last_used_at = current_kernel_time().tv_sec;
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100985 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 }
987 }
988
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 keyring = ERR_PTR(-ENOKEY);
Toshiyuki Okajimacea7daa2010-04-30 14:32:13 +0100990out:
991 read_unlock(&keyring_name_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 return keyring;
David Howellsa8b17ed2011-01-20 16:38:27 +0000993}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994
David Howellsb2a4df22013-09-24 10:35:18 +0100995static int keyring_detect_cycle_iterator(const void *object,
996 void *iterator_data)
997{
998 struct keyring_search_context *ctx = iterator_data;
999 const struct key *key = keyring_ptr_to_key(object);
1000
1001 kenter("{%d}", key->serial);
1002
1003 BUG_ON(key != ctx->match_data);
1004 ctx->result = ERR_PTR(-EDEADLK);
1005 return 1;
1006}
1007
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008/*
David Howells973c9f42011-01-20 16:38:33 +00001009 * See if a cycle will will be created by inserting acyclic tree B in acyclic
1010 * tree A at the topmost level (ie: as a direct child of A).
1011 *
1012 * Since we are adding B to A at the top level, checking for cycles should just
1013 * be a matter of seeing if node A is somewhere in tree B.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 */
1015static int keyring_detect_cycle(struct key *A, struct key *B)
1016{
David Howellsb2a4df22013-09-24 10:35:18 +01001017 struct keyring_search_context ctx = {
1018 .index_key = A->index_key,
1019 .match_data = A,
1020 .iterator = keyring_detect_cycle_iterator,
1021 .flags = (KEYRING_SEARCH_LOOKUP_DIRECT |
1022 KEYRING_SEARCH_NO_STATE_CHECK |
1023 KEYRING_SEARCH_NO_UPDATE_TIME |
1024 KEYRING_SEARCH_NO_CHECK_PERM |
1025 KEYRING_SEARCH_DETECT_TOO_DEEP),
1026 };
Linus Torvalds1da177e2005-04-16 15:20:36 -07001027
David Howells76d8aea2005-06-23 22:00:49 -07001028 rcu_read_lock();
David Howellsb2a4df22013-09-24 10:35:18 +01001029 search_nested_keyrings(B, &ctx);
David Howells76d8aea2005-06-23 22:00:49 -07001030 rcu_read_unlock();
David Howellsb2a4df22013-09-24 10:35:18 +01001031 return PTR_ERR(ctx.result) == -EAGAIN ? 0 : PTR_ERR(ctx.result);
David Howellsf70e2e02010-04-30 14:32:39 +01001032}
David Howellscab8eb52006-01-08 01:02:45 -08001033
David Howellscab8eb52006-01-08 01:02:45 -08001034/*
David Howells973c9f42011-01-20 16:38:33 +00001035 * Preallocate memory so that a key can be linked into to a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 */
David Howellsb2a4df22013-09-24 10:35:18 +01001037int __key_link_begin(struct key *keyring,
1038 const struct keyring_index_key *index_key,
1039 struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001040 __acquires(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001041 __acquires(&keyring_serialise_link_sem)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001042{
David Howellsb2a4df22013-09-24 10:35:18 +01001043 struct assoc_array_edit *edit;
1044 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045
David Howells16feef42013-09-24 10:35:15 +01001046 kenter("%d,%s,%s,",
David Howellsb2a4df22013-09-24 10:35:18 +01001047 keyring->serial, index_key->type->name, index_key->description);
1048
1049 BUG_ON(index_key->desc_len == 0);
David Howellsf70e2e02010-04-30 14:32:39 +01001050
1051 if (keyring->type != &key_type_keyring)
1052 return -ENOTDIR;
1053
1054 down_write(&keyring->sem);
1055
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 ret = -EKEYREVOKED;
David Howells76d8aea2005-06-23 22:00:49 -07001057 if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
David Howellsf70e2e02010-04-30 14:32:39 +01001058 goto error_krsem;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001059
David Howellsf70e2e02010-04-30 14:32:39 +01001060 /* serialise link/link calls to prevent parallel calls causing a cycle
1061 * when linking two keyring in opposite orders */
David Howells16feef42013-09-24 10:35:15 +01001062 if (index_key->type == &key_type_keyring)
David Howells553d6032010-04-30 14:32:28 +01001063 down_write(&keyring_serialise_link_sem);
1064
David Howellsb2a4df22013-09-24 10:35:18 +01001065 /* Create an edit script that will insert/replace the key in the
1066 * keyring tree.
1067 */
1068 edit = assoc_array_insert(&keyring->keys,
1069 &keyring_assoc_array_ops,
1070 index_key,
1071 NULL);
1072 if (IS_ERR(edit)) {
1073 ret = PTR_ERR(edit);
David Howells034faeb2013-10-30 11:15:24 +00001074 goto error_sem;
1075 }
1076
1077 /* If we're not replacing a link in-place then we're going to need some
1078 * extra quota.
1079 */
1080 if (!edit->dead_leaf) {
1081 ret = key_payload_reserve(keyring,
1082 keyring->datalen + KEYQUOTA_LINK_BYTES);
1083 if (ret < 0)
1084 goto error_cancel;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 }
1086
David Howellsb2a4df22013-09-24 10:35:18 +01001087 *_edit = edit;
David Howellsf70e2e02010-04-30 14:32:39 +01001088 kleave(" = 0");
1089 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090
David Howells034faeb2013-10-30 11:15:24 +00001091error_cancel:
1092 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001093error_sem:
David Howells16feef42013-09-24 10:35:15 +01001094 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001095 up_write(&keyring_serialise_link_sem);
1096error_krsem:
1097 up_write(&keyring->sem);
1098 kleave(" = %d", ret);
1099 return ret;
1100}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101
David Howellsf70e2e02010-04-30 14:32:39 +01001102/*
David Howells973c9f42011-01-20 16:38:33 +00001103 * Check already instantiated keys aren't going to be a problem.
1104 *
1105 * The caller must have called __key_link_begin(). Don't need to call this for
1106 * keys that were created since __key_link_begin() was called.
David Howellsf70e2e02010-04-30 14:32:39 +01001107 */
1108int __key_link_check_live_key(struct key *keyring, struct key *key)
1109{
1110 if (key->type == &key_type_keyring)
1111 /* check that we aren't going to create a cycle by linking one
1112 * keyring to another */
1113 return keyring_detect_cycle(keyring, key);
1114 return 0;
1115}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116
David Howellsf70e2e02010-04-30 14:32:39 +01001117/*
David Howells973c9f42011-01-20 16:38:33 +00001118 * Link a key into to a keyring.
1119 *
1120 * Must be called with __key_link_begin() having being called. Discards any
1121 * already extant link to matching key if there is one, so that each keyring
1122 * holds at most one link to any given key of a particular type+description
1123 * combination.
David Howellsf70e2e02010-04-30 14:32:39 +01001124 */
David Howellsb2a4df22013-09-24 10:35:18 +01001125void __key_link(struct key *key, struct assoc_array_edit **_edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001126{
David Howellsccc3e6d2013-09-24 10:35:16 +01001127 __key_get(key);
David Howellsb2a4df22013-09-24 10:35:18 +01001128 assoc_array_insert_set_object(*_edit, keyring_key_to_ptr(key));
1129 assoc_array_apply_edit(*_edit);
1130 *_edit = NULL;
David Howellsf70e2e02010-04-30 14:32:39 +01001131}
1132
1133/*
David Howells973c9f42011-01-20 16:38:33 +00001134 * Finish linking a key into to a keyring.
1135 *
1136 * Must be called with __key_link_begin() having being called.
David Howellsf70e2e02010-04-30 14:32:39 +01001137 */
David Howells16feef42013-09-24 10:35:15 +01001138void __key_link_end(struct key *keyring,
1139 const struct keyring_index_key *index_key,
David Howellsb2a4df22013-09-24 10:35:18 +01001140 struct assoc_array_edit *edit)
David Howellsf70e2e02010-04-30 14:32:39 +01001141 __releases(&keyring->sem)
David Howells423b97882012-05-21 12:32:13 +01001142 __releases(&keyring_serialise_link_sem)
David Howellsf70e2e02010-04-30 14:32:39 +01001143{
David Howells16feef42013-09-24 10:35:15 +01001144 BUG_ON(index_key->type == NULL);
David Howellsb2a4df22013-09-24 10:35:18 +01001145 kenter("%d,%s,", keyring->serial, index_key->type->name);
David Howellsf70e2e02010-04-30 14:32:39 +01001146
David Howells16feef42013-09-24 10:35:15 +01001147 if (index_key->type == &key_type_keyring)
David Howellsf70e2e02010-04-30 14:32:39 +01001148 up_write(&keyring_serialise_link_sem);
1149
David Howells034faeb2013-10-30 11:15:24 +00001150 if (edit && !edit->dead_leaf) {
David Howellsb2a4df22013-09-24 10:35:18 +01001151 key_payload_reserve(keyring,
1152 keyring->datalen - KEYQUOTA_LINK_BYTES);
1153 assoc_array_cancel_edit(edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001154 }
1155 up_write(&keyring->sem);
1156}
1157
David Howells973c9f42011-01-20 16:38:33 +00001158/**
1159 * key_link - Link a key to a keyring
1160 * @keyring: The keyring to make the link in.
1161 * @key: The key to link to.
1162 *
1163 * Make a link in a keyring to a key, such that the keyring holds a reference
1164 * on that key and the key can potentially be found by searching that keyring.
1165 *
1166 * This function will write-lock the keyring's semaphore and will consume some
1167 * of the user's key data quota to hold the link.
1168 *
1169 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring,
1170 * -EKEYREVOKED if the keyring has been revoked, -ENFILE if the keyring is
1171 * full, -EDQUOT if there is insufficient key data quota remaining to add
1172 * another link or -ENOMEM if there's insufficient memory.
1173 *
1174 * It is assumed that the caller has checked that it is permitted for a link to
1175 * be made (the keyring should have Write permission and the key Link
1176 * permission).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 */
1178int key_link(struct key *keyring, struct key *key)
1179{
David Howellsb2a4df22013-09-24 10:35:18 +01001180 struct assoc_array_edit *edit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181 int ret;
1182
David Howellsb2a4df22013-09-24 10:35:18 +01001183 kenter("{%d,%d}", keyring->serial, atomic_read(&keyring->usage));
1184
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185 key_check(keyring);
1186 key_check(key);
1187
David Howells008643b2013-08-30 16:07:37 +01001188 if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) &&
1189 !test_bit(KEY_FLAG_TRUSTED, &key->flags))
1190 return -EPERM;
1191
David Howellsb2a4df22013-09-24 10:35:18 +01001192 ret = __key_link_begin(keyring, &key->index_key, &edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001193 if (ret == 0) {
David Howellsb2a4df22013-09-24 10:35:18 +01001194 kdebug("begun {%d,%d}", keyring->serial, atomic_read(&keyring->usage));
David Howellsf70e2e02010-04-30 14:32:39 +01001195 ret = __key_link_check_live_key(keyring, key);
1196 if (ret == 0)
David Howellsb2a4df22013-09-24 10:35:18 +01001197 __key_link(key, &edit);
1198 __key_link_end(keyring, &key->index_key, edit);
David Howellsf70e2e02010-04-30 14:32:39 +01001199 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200
David Howellsb2a4df22013-09-24 10:35:18 +01001201 kleave(" = %d {%d,%d}", ret, keyring->serial, atomic_read(&keyring->usage));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 return ret;
David Howellsf70e2e02010-04-30 14:32:39 +01001203}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204EXPORT_SYMBOL(key_link);
1205
David Howells973c9f42011-01-20 16:38:33 +00001206/**
1207 * key_unlink - Unlink the first link to a key from a keyring.
1208 * @keyring: The keyring to remove the link from.
1209 * @key: The key the link is to.
1210 *
1211 * Remove a link from a keyring to a key.
1212 *
1213 * This function will write-lock the keyring's semaphore.
1214 *
1215 * Returns 0 if successful, -ENOTDIR if the keyring isn't a keyring, -ENOENT if
1216 * the key isn't linked to by the keyring or -ENOMEM if there's insufficient
1217 * memory.
1218 *
1219 * It is assumed that the caller has checked that it is permitted for a link to
1220 * be removed (the keyring should have Write permission; no permissions are
1221 * required on the key).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 */
1223int key_unlink(struct key *keyring, struct key *key)
1224{
David Howellsb2a4df22013-09-24 10:35:18 +01001225 struct assoc_array_edit *edit;
1226 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227
1228 key_check(keyring);
1229 key_check(key);
1230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 if (keyring->type != &key_type_keyring)
David Howellsb2a4df22013-09-24 10:35:18 +01001232 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
1234 down_write(&keyring->sem);
1235
David Howellsb2a4df22013-09-24 10:35:18 +01001236 edit = assoc_array_delete(&keyring->keys, &keyring_assoc_array_ops,
1237 &key->index_key);
1238 if (IS_ERR(edit)) {
1239 ret = PTR_ERR(edit);
1240 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242 ret = -ENOENT;
David Howellsb2a4df22013-09-24 10:35:18 +01001243 if (edit == NULL)
1244 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245
David Howellsb2a4df22013-09-24 10:35:18 +01001246 assoc_array_apply_edit(edit);
David Howells034faeb2013-10-30 11:15:24 +00001247 key_payload_reserve(keyring, keyring->datalen - KEYQUOTA_LINK_BYTES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 ret = 0;
1249
David Howells76d8aea2005-06-23 22:00:49 -07001250error:
David Howells76d8aea2005-06-23 22:00:49 -07001251 up_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001252 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001253}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254EXPORT_SYMBOL(key_unlink);
1255
David Howells973c9f42011-01-20 16:38:33 +00001256/**
1257 * keyring_clear - Clear a keyring
1258 * @keyring: The keyring to clear.
1259 *
1260 * Clear the contents of the specified keyring.
1261 *
1262 * Returns 0 if successful or -ENOTDIR if the keyring isn't a keyring.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263 */
1264int keyring_clear(struct key *keyring)
1265{
David Howellsb2a4df22013-09-24 10:35:18 +01001266 struct assoc_array_edit *edit;
David Howells76d8aea2005-06-23 22:00:49 -07001267 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268
David Howellsb2a4df22013-09-24 10:35:18 +01001269 if (keyring->type != &key_type_keyring)
1270 return -ENOTDIR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271
David Howellsb2a4df22013-09-24 10:35:18 +01001272 down_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273
David Howellsb2a4df22013-09-24 10:35:18 +01001274 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1275 if (IS_ERR(edit)) {
1276 ret = PTR_ERR(edit);
1277 } else {
1278 if (edit)
1279 assoc_array_apply_edit(edit);
1280 key_payload_reserve(keyring, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281 ret = 0;
1282 }
1283
David Howellsb2a4df22013-09-24 10:35:18 +01001284 up_write(&keyring->sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +00001286}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287EXPORT_SYMBOL(keyring_clear);
David Howells31204ed2006-06-26 00:24:51 -07001288
David Howells31204ed2006-06-26 00:24:51 -07001289/*
David Howells973c9f42011-01-20 16:38:33 +00001290 * Dispose of the links from a revoked keyring.
1291 *
1292 * This is called with the key sem write-locked.
David Howells31204ed2006-06-26 00:24:51 -07001293 */
1294static void keyring_revoke(struct key *keyring)
1295{
David Howellsb2a4df22013-09-24 10:35:18 +01001296 struct assoc_array_edit *edit;
David Howellsf0641cb2010-04-30 14:32:18 +01001297
David Howellsb2a4df22013-09-24 10:35:18 +01001298 edit = assoc_array_clear(&keyring->keys, &keyring_assoc_array_ops);
1299 if (!IS_ERR(edit)) {
1300 if (edit)
1301 assoc_array_apply_edit(edit);
1302 key_payload_reserve(keyring, 0);
David Howells31204ed2006-06-26 00:24:51 -07001303 }
David Howellsa8b17ed2011-01-20 16:38:27 +00001304}
David Howells5d135442009-09-02 09:14:00 +01001305
David Howells62fe3182013-11-14 13:02:31 +00001306static bool keyring_gc_select_iterator(void *object, void *iterator_data)
David Howellsb2a4df22013-09-24 10:35:18 +01001307{
1308 struct key *key = keyring_ptr_to_key(object);
1309 time_t *limit = iterator_data;
1310
1311 if (key_is_dead(key, *limit))
1312 return false;
1313 key_get(key);
1314 return true;
1315}
1316
David Howells62fe3182013-11-14 13:02:31 +00001317static int keyring_gc_check_iterator(const void *object, void *iterator_data)
1318{
1319 const struct key *key = keyring_ptr_to_key(object);
1320 time_t *limit = iterator_data;
1321
1322 key_check(key);
1323 return key_is_dead(key, *limit);
1324}
1325
David Howells5d135442009-09-02 09:14:00 +01001326/*
David Howells62fe3182013-11-14 13:02:31 +00001327 * Garbage collect pointers from a keyring.
David Howells973c9f42011-01-20 16:38:33 +00001328 *
David Howells62fe3182013-11-14 13:02:31 +00001329 * Not called with any locks held. The keyring's key struct will not be
1330 * deallocated under us as only our caller may deallocate it.
David Howells5d135442009-09-02 09:14:00 +01001331 */
1332void keyring_gc(struct key *keyring, time_t limit)
1333{
David Howells62fe3182013-11-14 13:02:31 +00001334 int result;
David Howells5d135442009-09-02 09:14:00 +01001335
David Howells62fe3182013-11-14 13:02:31 +00001336 kenter("%x{%s}", keyring->serial, keyring->description ?: "");
1337
1338 if (keyring->flags & ((1 << KEY_FLAG_INVALIDATED) |
1339 (1 << KEY_FLAG_REVOKED)))
1340 goto dont_gc;
1341
1342 /* scan the keyring looking for dead keys */
1343 rcu_read_lock();
1344 result = assoc_array_iterate(&keyring->keys,
1345 keyring_gc_check_iterator, &limit);
1346 rcu_read_unlock();
1347 if (result == true)
1348 goto do_gc;
1349
1350dont_gc:
1351 kleave(" [no gc]");
1352 return;
1353
1354do_gc:
David Howells5d135442009-09-02 09:14:00 +01001355 down_write(&keyring->sem);
David Howellsb2a4df22013-09-24 10:35:18 +01001356 assoc_array_gc(&keyring->keys, &keyring_assoc_array_ops,
David Howells62fe3182013-11-14 13:02:31 +00001357 keyring_gc_select_iterator, &limit);
David Howells5d135442009-09-02 09:14:00 +01001358 up_write(&keyring->sem);
David Howells62fe3182013-11-14 13:02:31 +00001359 kleave(" [gc]");
David Howells5d135442009-09-02 09:14:00 +01001360}