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[cor_2_6_31.git] / crypto / api.c
blobd5944f92b4162845e305c9dc6f2df85576808240
1 /*
2 * Scatterlist Cryptographic API.
3 *
4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
5 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
6 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
9 * and Nettle, by Niels Möller.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 *
16 */
17
18 #include <linux/err.h>
19 #include <linux/errno.h>
20 #include <linux/kernel.h>
21 #include <linux/kmod.h>
22 #include <linux/module.h>
23 #include <linux/param.h>
24 #include <linux/sched.h>
25 #include <linux/slab.h>
26 #include <linux/string.h>
27 #include "internal.h"
28
29 LIST_HEAD(crypto_alg_list);
30 EXPORT_SYMBOL_GPL(crypto_alg_list);
31 DECLARE_RWSEM(crypto_alg_sem);
32 EXPORT_SYMBOL_GPL(crypto_alg_sem);
33
34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
35 EXPORT_SYMBOL_GPL(crypto_chain);
36
37 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
38 {
39 atomic_inc(&alg->cra_refcnt);
40 return alg;
41 }
42
43 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
44 {
45 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
46 }
47 EXPORT_SYMBOL_GPL(crypto_mod_get);
48
49 void crypto_mod_put(struct crypto_alg *alg)
50 {
51 struct module *module = alg->cra_module;
52
53 crypto_alg_put(alg);
54 module_put(module);
55 }
56 EXPORT_SYMBOL_GPL(crypto_mod_put);
57
58 static inline int crypto_is_test_larval(struct crypto_larval *larval)
59 {
60 return larval->alg.cra_driver_name[0];
61 }
62
63 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
64 u32 mask)
65 {
66 struct crypto_alg *q, *alg = NULL;
67 int best = -2;
68
69 list_for_each_entry(q, &crypto_alg_list, cra_list) {
70 int exact, fuzzy;
71
72 if (crypto_is_moribund(q))
73 continue;
74
75 if ((q->cra_flags ^ type) & mask)
76 continue;
77
78 if (crypto_is_larval(q) &&
79 !crypto_is_test_larval((struct crypto_larval *)q) &&
80 ((struct crypto_larval *)q)->mask != mask)
81 continue;
82
83 exact = !strcmp(q->cra_driver_name, name);
84 fuzzy = !strcmp(q->cra_name, name);
85 if (!exact && !(fuzzy && q->cra_priority > best))
86 continue;
87
88 if (unlikely(!crypto_mod_get(q)))
89 continue;
90
91 best = q->cra_priority;
92 if (alg)
93 crypto_mod_put(alg);
94 alg = q;
95
96 if (exact)
97 break;
98 }
99
100 return alg;
101 }
102
103 static void crypto_larval_destroy(struct crypto_alg *alg)
104 {
105 struct crypto_larval *larval = (void *)alg;
106
107 BUG_ON(!crypto_is_larval(alg));
108 if (larval->adult)
109 crypto_mod_put(larval->adult);
110 kfree(larval);
111 }
112
113 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
114 {
115 struct crypto_larval *larval;
116
117 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
118 if (!larval)
119 return ERR_PTR(-ENOMEM);
120
121 larval->mask = mask;
122 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
123 larval->alg.cra_priority = -1;
124 larval->alg.cra_destroy = crypto_larval_destroy;
125
126 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
127 init_completion(&larval->completion);
128
129 return larval;
130 }
131 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
132
133 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
134 u32 mask)
135 {
136 struct crypto_alg *alg;
137 struct crypto_larval *larval;
138
139 larval = crypto_larval_alloc(name, type, mask);
140 if (IS_ERR(larval))
141 return ERR_CAST(larval);
142
143 atomic_set(&larval->alg.cra_refcnt, 2);
144
145 down_write(&crypto_alg_sem);
146 alg = __crypto_alg_lookup(name, type, mask);
147 if (!alg) {
148 alg = &larval->alg;
149 list_add(&alg->cra_list, &crypto_alg_list);
150 }
151 up_write(&crypto_alg_sem);
152
153 if (alg != &larval->alg)
154 kfree(larval);
155
156 return alg;
157 }
158
159 void crypto_larval_kill(struct crypto_alg *alg)
160 {
161 struct crypto_larval *larval = (void *)alg;
162
163 down_write(&crypto_alg_sem);
164 list_del(&alg->cra_list);
165 up_write(&crypto_alg_sem);
166 complete_all(&larval->completion);
167 crypto_alg_put(alg);
168 }
169 EXPORT_SYMBOL_GPL(crypto_larval_kill);
170
171 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
172 {
173 struct crypto_larval *larval = (void *)alg;
174 long timeout;
175
176 timeout = wait_for_completion_interruptible_timeout(
177 &larval->completion, 60 * HZ);
178
179 alg = larval->adult;
180 if (timeout < 0)
181 alg = ERR_PTR(-EINTR);
182 else if (!timeout)
183 alg = ERR_PTR(-ETIMEDOUT);
184 else if (!alg)
185 alg = ERR_PTR(-ENOENT);
186 else if (crypto_is_test_larval(larval) &&
187 !(alg->cra_flags & CRYPTO_ALG_TESTED))
188 alg = ERR_PTR(-EAGAIN);
189 else if (!crypto_mod_get(alg))
190 alg = ERR_PTR(-EAGAIN);
191 crypto_mod_put(&larval->alg);
192
193 return alg;
194 }
195
196 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
197 {
198 struct crypto_alg *alg;
199
200 down_read(&crypto_alg_sem);
201 alg = __crypto_alg_lookup(name, type, mask);
202 up_read(&crypto_alg_sem);
203
204 return alg;
205 }
206 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
207
208 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
209 {
210 struct crypto_alg *alg;
211
212 if (!name)
213 return ERR_PTR(-ENOENT);
214
215 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
216 type &= mask;
217
218 alg = crypto_alg_lookup(name, type, mask);
219 if (!alg) {
220 request_module("%s", name);
221
222 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
223 CRYPTO_ALG_NEED_FALLBACK))
224 request_module("%s-all", name);
225
226 alg = crypto_alg_lookup(name, type, mask);
227 }
228
229 if (alg)
230 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
231
232 return crypto_larval_add(name, type, mask);
233 }
234 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
235
236 int crypto_probing_notify(unsigned long val, void *v)
237 {
238 int ok;
239
240 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
241 if (ok == NOTIFY_DONE) {
242 request_module("cryptomgr");
243 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
244 }
245
246 return ok;
247 }
248 EXPORT_SYMBOL_GPL(crypto_probing_notify);
249
250 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
251 {
252 struct crypto_alg *alg;
253 struct crypto_alg *larval;
254 int ok;
255
256 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
257 type |= CRYPTO_ALG_TESTED;
258 mask |= CRYPTO_ALG_TESTED;
259 }
260
261 larval = crypto_larval_lookup(name, type, mask);
262 if (IS_ERR(larval) || !crypto_is_larval(larval))
263 return larval;
264
265 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
266
267 if (ok == NOTIFY_STOP)
268 alg = crypto_larval_wait(larval);
269 else {
270 crypto_mod_put(larval);
271 alg = ERR_PTR(-ENOENT);
272 }
273 crypto_larval_kill(larval);
274 return alg;
275 }
276 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
277
278 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
279 {
280 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
281
282 if (type_obj)
283 return type_obj->init(tfm, type, mask);
284
285 switch (crypto_tfm_alg_type(tfm)) {
286 case CRYPTO_ALG_TYPE_CIPHER:
287 return crypto_init_cipher_ops(tfm);
288
289 case CRYPTO_ALG_TYPE_DIGEST:
290 if ((mask & CRYPTO_ALG_TYPE_HASH_MASK) !=
291 CRYPTO_ALG_TYPE_HASH_MASK)
292 return crypto_init_digest_ops_async(tfm);
293 else
294 return crypto_init_digest_ops(tfm);
295
296 case CRYPTO_ALG_TYPE_COMPRESS:
297 return crypto_init_compress_ops(tfm);
298
299 default:
300 break;
301 }
302
303 BUG();
304 return -EINVAL;
305 }
306
307 static void crypto_exit_ops(struct crypto_tfm *tfm)
308 {
309 const struct crypto_type *type = tfm->__crt_alg->cra_type;
310
311 if (type) {
312 if (tfm->exit)
313 tfm->exit(tfm);
314 return;
315 }
316
317 switch (crypto_tfm_alg_type(tfm)) {
318 case CRYPTO_ALG_TYPE_CIPHER:
319 crypto_exit_cipher_ops(tfm);
320 break;
321
322 case CRYPTO_ALG_TYPE_DIGEST:
323 crypto_exit_digest_ops(tfm);
324 break;
325
326 case CRYPTO_ALG_TYPE_COMPRESS:
327 crypto_exit_compress_ops(tfm);
328 break;
329
330 default:
331 BUG();
332
333 }
334 }
335
336 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
337 {
338 const struct crypto_type *type_obj = alg->cra_type;
339 unsigned int len;
340
341 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
342 if (type_obj)
343 return len + type_obj->ctxsize(alg, type, mask);
344
345 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
346 default:
347 BUG();
348
349 case CRYPTO_ALG_TYPE_CIPHER:
350 len += crypto_cipher_ctxsize(alg);
351 break;
352
353 case CRYPTO_ALG_TYPE_DIGEST:
354 len += crypto_digest_ctxsize(alg);
355 break;
356
357 case CRYPTO_ALG_TYPE_COMPRESS:
358 len += crypto_compress_ctxsize(alg);
359 break;
360 }
361
362 return len;
363 }
364
365 void crypto_shoot_alg(struct crypto_alg *alg)
366 {
367 down_write(&crypto_alg_sem);
368 alg->cra_flags |= CRYPTO_ALG_DYING;
369 up_write(&crypto_alg_sem);
370 }
371 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
372
373 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
374 u32 mask)
375 {
376 struct crypto_tfm *tfm = NULL;
377 unsigned int tfm_size;
378 int err = -ENOMEM;
379
380 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
381 tfm = kzalloc(tfm_size, GFP_KERNEL);
382 if (tfm == NULL)
383 goto out_err;
384
385 tfm->__crt_alg = alg;
386
387 err = crypto_init_ops(tfm, type, mask);
388 if (err)
389 goto out_free_tfm;
390
391 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
392 goto cra_init_failed;
393
394 goto out;
395
396 cra_init_failed:
397 crypto_exit_ops(tfm);
398 out_free_tfm:
399 if (err == -EAGAIN)
400 crypto_shoot_alg(alg);
401 kfree(tfm);
402 out_err:
403 tfm = ERR_PTR(err);
404 out:
405 return tfm;
406 }
407 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
408
409 /*
410 * crypto_alloc_base - Locate algorithm and allocate transform
411 * @alg_name: Name of algorithm
412 * @type: Type of algorithm
413 * @mask: Mask for type comparison
414 *
415 * This function should not be used by new algorithm types.
416 * Plesae use crypto_alloc_tfm instead.
417 *
418 * crypto_alloc_base() will first attempt to locate an already loaded
419 * algorithm. If that fails and the kernel supports dynamically loadable
420 * modules, it will then attempt to load a module of the same name or
421 * alias. If that fails it will send a query to any loaded crypto manager
422 * to construct an algorithm on the fly. A refcount is grabbed on the
423 * algorithm which is then associated with the new transform.
424 *
425 * The returned transform is of a non-determinate type. Most people
426 * should use one of the more specific allocation functions such as
427 * crypto_alloc_blkcipher.
428 *
429 * In case of error the return value is an error pointer.
430 */
431 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
432 {
433 struct crypto_tfm *tfm;
434 int err;
435
436 for (;;) {
437 struct crypto_alg *alg;
438
439 alg = crypto_alg_mod_lookup(alg_name, type, mask);
440 if (IS_ERR(alg)) {
441 err = PTR_ERR(alg);
442 goto err;
443 }
444
445 tfm = __crypto_alloc_tfm(alg, type, mask);
446 if (!IS_ERR(tfm))
447 return tfm;
448
449 crypto_mod_put(alg);
450 err = PTR_ERR(tfm);
451
452 err:
453 if (err != -EAGAIN)
454 break;
455 if (signal_pending(current)) {
456 err = -EINTR;
457 break;
458 }
459 }
460
461 return ERR_PTR(err);
462 }
463 EXPORT_SYMBOL_GPL(crypto_alloc_base);
464
465 void *crypto_create_tfm(struct crypto_alg *alg,
466 const struct crypto_type *frontend)
467 {
468 char *mem;
469 struct crypto_tfm *tfm = NULL;
470 unsigned int tfmsize;
471 unsigned int total;
472 int err = -ENOMEM;
473
474 tfmsize = frontend->tfmsize;
475 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);
476
477 mem = kzalloc(total, GFP_KERNEL);
478 if (mem == NULL)
479 goto out_err;
480
481 tfm = (struct crypto_tfm *)(mem + tfmsize);
482 tfm->__crt_alg = alg;
483
484 err = frontend->init_tfm(tfm, frontend);
485 if (err)
486 goto out_free_tfm;
487
488 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
489 goto cra_init_failed;
490
491 goto out;
492
493 cra_init_failed:
494 crypto_exit_ops(tfm);
495 out_free_tfm:
496 if (err == -EAGAIN)
497 crypto_shoot_alg(alg);
498 kfree(mem);
499 out_err:
500 mem = ERR_PTR(err);
501 out:
502 return mem;
503 }
504 EXPORT_SYMBOL_GPL(crypto_create_tfm);
505
506 /*
507 * crypto_alloc_tfm - Locate algorithm and allocate transform
508 * @alg_name: Name of algorithm
509 * @frontend: Frontend algorithm type
510 * @type: Type of algorithm
511 * @mask: Mask for type comparison
512 *
513 * crypto_alloc_tfm() will first attempt to locate an already loaded
514 * algorithm. If that fails and the kernel supports dynamically loadable
515 * modules, it will then attempt to load a module of the same name or
516 * alias. If that fails it will send a query to any loaded crypto manager
517 * to construct an algorithm on the fly. A refcount is grabbed on the
518 * algorithm which is then associated with the new transform.
519 *
520 * The returned transform is of a non-determinate type. Most people
521 * should use one of the more specific allocation functions such as
522 * crypto_alloc_blkcipher.
523 *
524 * In case of error the return value is an error pointer.
525 */
526 void *crypto_alloc_tfm(const char *alg_name,
527 const struct crypto_type *frontend, u32 type, u32 mask)
528 {
529 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
530 void *tfm;
531 int err;
532
533 type &= frontend->maskclear;
534 mask &= frontend->maskclear;
535 type |= frontend->type;
536 mask |= frontend->maskset;
537
538 lookup = frontend->lookup ?: crypto_alg_mod_lookup;
539
540 for (;;) {
541 struct crypto_alg *alg;
542
543 alg = lookup(alg_name, type, mask);
544 if (IS_ERR(alg)) {
545 err = PTR_ERR(alg);
546 goto err;
547 }
548
549 tfm = crypto_create_tfm(alg, frontend);
550 if (!IS_ERR(tfm))
551 return tfm;
552
553 crypto_mod_put(alg);
554 err = PTR_ERR(tfm);
555
556 err:
557 if (err != -EAGAIN)
558 break;
559 if (signal_pending(current)) {
560 err = -EINTR;
561 break;
562 }
563 }
564
565 return ERR_PTR(err);
566 }
567 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
568
569 /*
570 * crypto_destroy_tfm - Free crypto transform
571 * @mem: Start of tfm slab
572 * @tfm: Transform to free
573 *
574 * This function frees up the transform and any associated resources,
575 * then drops the refcount on the associated algorithm.
576 */
577 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
578 {
579 struct crypto_alg *alg;
580
581 if (unlikely(!mem))
582 return;
583
584 alg = tfm->__crt_alg;
585
586 if (!tfm->exit && alg->cra_exit)
587 alg->cra_exit(tfm);
588 crypto_exit_ops(tfm);
589 crypto_mod_put(alg);
590 kzfree(mem);
591 }
592 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
593
594 int crypto_has_alg(const char *name, u32 type, u32 mask)
595 {
596 int ret = 0;
597 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
598
599 if (!IS_ERR(alg)) {
600 crypto_mod_put(alg);
601 ret = 1;
602 }
603
604 return ret;
605 }
606 EXPORT_SYMBOL_GPL(crypto_has_alg);
607
608 MODULE_DESCRIPTION("Cryptographic core API");
609 MODULE_LICENSE("GPL");
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