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Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6/verdex.git] / crypto / api.c
blob9975a7bd246c21d4d7e3152249ffefdb38812ee5
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 = try_then_request_module(crypto_alg_lookup(name, type, mask),
219 name);
220 if (alg)
221 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
222
223 return crypto_larval_add(name, type, mask);
224 }
225 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
226
227 int crypto_probing_notify(unsigned long val, void *v)
228 {
229 int ok;
230
231 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
232 if (ok == NOTIFY_DONE) {
233 request_module("cryptomgr");
234 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
235 }
236
237 return ok;
238 }
239 EXPORT_SYMBOL_GPL(crypto_probing_notify);
240
241 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
242 {
243 struct crypto_alg *alg;
244 struct crypto_alg *larval;
245 int ok;
246
247 if (!(mask & CRYPTO_ALG_TESTED)) {
248 type |= CRYPTO_ALG_TESTED;
249 mask |= CRYPTO_ALG_TESTED;
250 }
251
252 larval = crypto_larval_lookup(name, type, mask);
253 if (IS_ERR(larval) || !crypto_is_larval(larval))
254 return larval;
255
256 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
257
258 if (ok == NOTIFY_STOP)
259 alg = crypto_larval_wait(larval);
260 else {
261 crypto_mod_put(larval);
262 alg = ERR_PTR(-ENOENT);
263 }
264 crypto_larval_kill(larval);
265 return alg;
266 }
267 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
268
269 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
270 {
271 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
272
273 if (type_obj)
274 return type_obj->init(tfm, type, mask);
275
276 switch (crypto_tfm_alg_type(tfm)) {
277 case CRYPTO_ALG_TYPE_CIPHER:
278 return crypto_init_cipher_ops(tfm);
279
280 case CRYPTO_ALG_TYPE_DIGEST:
281 if ((mask & CRYPTO_ALG_TYPE_HASH_MASK) !=
282 CRYPTO_ALG_TYPE_HASH_MASK)
283 return crypto_init_digest_ops_async(tfm);
284 else
285 return crypto_init_digest_ops(tfm);
286
287 case CRYPTO_ALG_TYPE_COMPRESS:
288 return crypto_init_compress_ops(tfm);
289
290 default:
291 break;
292 }
293
294 BUG();
295 return -EINVAL;
296 }
297
298 static void crypto_exit_ops(struct crypto_tfm *tfm)
299 {
300 const struct crypto_type *type = tfm->__crt_alg->cra_type;
301
302 if (type) {
303 if (tfm->exit)
304 tfm->exit(tfm);
305 return;
306 }
307
308 switch (crypto_tfm_alg_type(tfm)) {
309 case CRYPTO_ALG_TYPE_CIPHER:
310 crypto_exit_cipher_ops(tfm);
311 break;
312
313 case CRYPTO_ALG_TYPE_DIGEST:
314 crypto_exit_digest_ops(tfm);
315 break;
316
317 case CRYPTO_ALG_TYPE_COMPRESS:
318 crypto_exit_compress_ops(tfm);
319 break;
320
321 default:
322 BUG();
323
324 }
325 }
326
327 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
328 {
329 const struct crypto_type *type_obj = alg->cra_type;
330 unsigned int len;
331
332 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
333 if (type_obj)
334 return len + type_obj->ctxsize(alg, type, mask);
335
336 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
337 default:
338 BUG();
339
340 case CRYPTO_ALG_TYPE_CIPHER:
341 len += crypto_cipher_ctxsize(alg);
342 break;
343
344 case CRYPTO_ALG_TYPE_DIGEST:
345 len += crypto_digest_ctxsize(alg);
346 break;
347
348 case CRYPTO_ALG_TYPE_COMPRESS:
349 len += crypto_compress_ctxsize(alg);
350 break;
351 }
352
353 return len;
354 }
355
356 void crypto_shoot_alg(struct crypto_alg *alg)
357 {
358 down_write(&crypto_alg_sem);
359 alg->cra_flags |= CRYPTO_ALG_DYING;
360 up_write(&crypto_alg_sem);
361 }
362 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
363
364 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
365 u32 mask)
366 {
367 struct crypto_tfm *tfm = NULL;
368 unsigned int tfm_size;
369 int err = -ENOMEM;
370
371 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
372 tfm = kzalloc(tfm_size, GFP_KERNEL);
373 if (tfm == NULL)
374 goto out_err;
375
376 tfm->__crt_alg = alg;
377
378 err = crypto_init_ops(tfm, type, mask);
379 if (err)
380 goto out_free_tfm;
381
382 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
383 goto cra_init_failed;
384
385 goto out;
386
387 cra_init_failed:
388 crypto_exit_ops(tfm);
389 out_free_tfm:
390 if (err == -EAGAIN)
391 crypto_shoot_alg(alg);
392 kfree(tfm);
393 out_err:
394 tfm = ERR_PTR(err);
395 out:
396 return tfm;
397 }
398 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
399
400 /*
401 * crypto_alloc_base - Locate algorithm and allocate transform
402 * @alg_name: Name of algorithm
403 * @type: Type of algorithm
404 * @mask: Mask for type comparison
405 *
406 * This function should not be used by new algorithm types.
407 * Plesae use crypto_alloc_tfm instead.
408 *
409 * crypto_alloc_base() will first attempt to locate an already loaded
410 * algorithm. If that fails and the kernel supports dynamically loadable
411 * modules, it will then attempt to load a module of the same name or
412 * alias. If that fails it will send a query to any loaded crypto manager
413 * to construct an algorithm on the fly. A refcount is grabbed on the
414 * algorithm which is then associated with the new transform.
415 *
416 * The returned transform is of a non-determinate type. Most people
417 * should use one of the more specific allocation functions such as
418 * crypto_alloc_blkcipher.
419 *
420 * In case of error the return value is an error pointer.
421 */
422 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
423 {
424 struct crypto_tfm *tfm;
425 int err;
426
427 for (;;) {
428 struct crypto_alg *alg;
429
430 alg = crypto_alg_mod_lookup(alg_name, type, mask);
431 if (IS_ERR(alg)) {
432 err = PTR_ERR(alg);
433 goto err;
434 }
435
436 tfm = __crypto_alloc_tfm(alg, type, mask);
437 if (!IS_ERR(tfm))
438 return tfm;
439
440 crypto_mod_put(alg);
441 err = PTR_ERR(tfm);
442
443 err:
444 if (err != -EAGAIN)
445 break;
446 if (signal_pending(current)) {
447 err = -EINTR;
448 break;
449 }
450 }
451
452 return ERR_PTR(err);
453 }
454 EXPORT_SYMBOL_GPL(crypto_alloc_base);
455
456 struct crypto_tfm *crypto_create_tfm(struct crypto_alg *alg,
457 const struct crypto_type *frontend)
458 {
459 char *mem;
460 struct crypto_tfm *tfm = NULL;
461 unsigned int tfmsize;
462 unsigned int total;
463 int err = -ENOMEM;
464
465 tfmsize = frontend->tfmsize;
466 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);
467
468 mem = kzalloc(total, GFP_KERNEL);
469 if (mem == NULL)
470 goto out_err;
471
472 tfm = (struct crypto_tfm *)(mem + tfmsize);
473 tfm->__crt_alg = alg;
474
475 err = frontend->init_tfm(tfm, frontend);
476 if (err)
477 goto out_free_tfm;
478
479 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
480 goto cra_init_failed;
481
482 goto out;
483
484 cra_init_failed:
485 crypto_exit_ops(tfm);
486 out_free_tfm:
487 if (err == -EAGAIN)
488 crypto_shoot_alg(alg);
489 kfree(mem);
490 out_err:
491 tfm = ERR_PTR(err);
492 out:
493 return tfm;
494 }
495 EXPORT_SYMBOL_GPL(crypto_create_tfm);
496
497 /*
498 * crypto_alloc_tfm - Locate algorithm and allocate transform
499 * @alg_name: Name of algorithm
500 * @frontend: Frontend algorithm type
501 * @type: Type of algorithm
502 * @mask: Mask for type comparison
503 *
504 * crypto_alloc_tfm() will first attempt to locate an already loaded
505 * algorithm. If that fails and the kernel supports dynamically loadable
506 * modules, it will then attempt to load a module of the same name or
507 * alias. If that fails it will send a query to any loaded crypto manager
508 * to construct an algorithm on the fly. A refcount is grabbed on the
509 * algorithm which is then associated with the new transform.
510 *
511 * The returned transform is of a non-determinate type. Most people
512 * should use one of the more specific allocation functions such as
513 * crypto_alloc_blkcipher.
514 *
515 * In case of error the return value is an error pointer.
516 */
517 struct crypto_tfm *crypto_alloc_tfm(const char *alg_name,
518 const struct crypto_type *frontend,
519 u32 type, u32 mask)
520 {
521 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
522 struct crypto_tfm *tfm;
523 int err;
524
525 type &= frontend->maskclear;
526 mask &= frontend->maskclear;
527 type |= frontend->type;
528 mask |= frontend->maskset;
529
530 lookup = frontend->lookup ?: crypto_alg_mod_lookup;
531
532 for (;;) {
533 struct crypto_alg *alg;
534
535 alg = lookup(alg_name, type, mask);
536 if (IS_ERR(alg)) {
537 err = PTR_ERR(alg);
538 goto err;
539 }
540
541 tfm = crypto_create_tfm(alg, frontend);
542 if (!IS_ERR(tfm))
543 return tfm;
544
545 crypto_mod_put(alg);
546 err = PTR_ERR(tfm);
547
548 err:
549 if (err != -EAGAIN)
550 break;
551 if (signal_pending(current)) {
552 err = -EINTR;
553 break;
554 }
555 }
556
557 return ERR_PTR(err);
558 }
559 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
560
561 /*
562 * crypto_free_tfm - Free crypto transform
563 * @tfm: Transform to free
564 *
565 * crypto_free_tfm() frees up the transform and any associated resources,
566 * then drops the refcount on the associated algorithm.
567 */
568 void crypto_free_tfm(struct crypto_tfm *tfm)
569 {
570 struct crypto_alg *alg;
571 int size;
572
573 if (unlikely(!tfm))
574 return;
575
576 alg = tfm->__crt_alg;
577 size = sizeof(*tfm) + alg->cra_ctxsize;
578
579 if (!tfm->exit && alg->cra_exit)
580 alg->cra_exit(tfm);
581 crypto_exit_ops(tfm);
582 crypto_mod_put(alg);
583 memset(tfm, 0, size);
584 kfree(tfm);
585 }
586
587 EXPORT_SYMBOL_GPL(crypto_free_tfm);
588
589 int crypto_has_alg(const char *name, u32 type, u32 mask)
590 {
591 int ret = 0;
592 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
593
594 if (!IS_ERR(alg)) {
595 crypto_mod_put(alg);
596 ret = 1;
597 }
598
599 return ret;
600 }
601 EXPORT_SYMBOL_GPL(crypto_has_alg);
602
603 MODULE_DESCRIPTION("Cryptographic core API");
604 MODULE_LICENSE("GPL");
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