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Btrfs: adjust NULL test
[linux-2.6/mini2440.git] / crypto / api.c
blobfd2545decb280a6045c1c5fa19447e6bc1fbe907
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 char tmp[CRYPTO_MAX_ALG_NAME];
221
222 request_module(name);
223
224 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
225 CRYPTO_ALG_NEED_FALLBACK) &&
226 snprintf(tmp, sizeof(tmp), "%s-all", name) < sizeof(tmp))
227 request_module(tmp);
228
229 alg = crypto_alg_lookup(name, type, mask);
230 }
231
232 if (alg)
233 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
234
235 return crypto_larval_add(name, type, mask);
236 }
237 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
238
239 int crypto_probing_notify(unsigned long val, void *v)
240 {
241 int ok;
242
243 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
244 if (ok == NOTIFY_DONE) {
245 request_module("cryptomgr");
246 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
247 }
248
249 return ok;
250 }
251 EXPORT_SYMBOL_GPL(crypto_probing_notify);
252
253 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
254 {
255 struct crypto_alg *alg;
256 struct crypto_alg *larval;
257 int ok;
258
259 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
260 type |= CRYPTO_ALG_TESTED;
261 mask |= CRYPTO_ALG_TESTED;
262 }
263
264 larval = crypto_larval_lookup(name, type, mask);
265 if (IS_ERR(larval) || !crypto_is_larval(larval))
266 return larval;
267
268 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
269
270 if (ok == NOTIFY_STOP)
271 alg = crypto_larval_wait(larval);
272 else {
273 crypto_mod_put(larval);
274 alg = ERR_PTR(-ENOENT);
275 }
276 crypto_larval_kill(larval);
277 return alg;
278 }
279 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
280
281 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
282 {
283 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
284
285 if (type_obj)
286 return type_obj->init(tfm, type, mask);
287
288 switch (crypto_tfm_alg_type(tfm)) {
289 case CRYPTO_ALG_TYPE_CIPHER:
290 return crypto_init_cipher_ops(tfm);
291
292 case CRYPTO_ALG_TYPE_DIGEST:
293 if ((mask & CRYPTO_ALG_TYPE_HASH_MASK) !=
294 CRYPTO_ALG_TYPE_HASH_MASK)
295 return crypto_init_digest_ops_async(tfm);
296 else
297 return crypto_init_digest_ops(tfm);
298
299 case CRYPTO_ALG_TYPE_COMPRESS:
300 return crypto_init_compress_ops(tfm);
301
302 default:
303 break;
304 }
305
306 BUG();
307 return -EINVAL;
308 }
309
310 static void crypto_exit_ops(struct crypto_tfm *tfm)
311 {
312 const struct crypto_type *type = tfm->__crt_alg->cra_type;
313
314 if (type) {
315 if (tfm->exit)
316 tfm->exit(tfm);
317 return;
318 }
319
320 switch (crypto_tfm_alg_type(tfm)) {
321 case CRYPTO_ALG_TYPE_CIPHER:
322 crypto_exit_cipher_ops(tfm);
323 break;
324
325 case CRYPTO_ALG_TYPE_DIGEST:
326 crypto_exit_digest_ops(tfm);
327 break;
328
329 case CRYPTO_ALG_TYPE_COMPRESS:
330 crypto_exit_compress_ops(tfm);
331 break;
332
333 default:
334 BUG();
335
336 }
337 }
338
339 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
340 {
341 const struct crypto_type *type_obj = alg->cra_type;
342 unsigned int len;
343
344 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
345 if (type_obj)
346 return len + type_obj->ctxsize(alg, type, mask);
347
348 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
349 default:
350 BUG();
351
352 case CRYPTO_ALG_TYPE_CIPHER:
353 len += crypto_cipher_ctxsize(alg);
354 break;
355
356 case CRYPTO_ALG_TYPE_DIGEST:
357 len += crypto_digest_ctxsize(alg);
358 break;
359
360 case CRYPTO_ALG_TYPE_COMPRESS:
361 len += crypto_compress_ctxsize(alg);
362 break;
363 }
364
365 return len;
366 }
367
368 void crypto_shoot_alg(struct crypto_alg *alg)
369 {
370 down_write(&crypto_alg_sem);
371 alg->cra_flags |= CRYPTO_ALG_DYING;
372 up_write(&crypto_alg_sem);
373 }
374 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
375
376 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
377 u32 mask)
378 {
379 struct crypto_tfm *tfm = NULL;
380 unsigned int tfm_size;
381 int err = -ENOMEM;
382
383 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
384 tfm = kzalloc(tfm_size, GFP_KERNEL);
385 if (tfm == NULL)
386 goto out_err;
387
388 tfm->__crt_alg = alg;
389
390 err = crypto_init_ops(tfm, type, mask);
391 if (err)
392 goto out_free_tfm;
393
394 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
395 goto cra_init_failed;
396
397 goto out;
398
399 cra_init_failed:
400 crypto_exit_ops(tfm);
401 out_free_tfm:
402 if (err == -EAGAIN)
403 crypto_shoot_alg(alg);
404 kfree(tfm);
405 out_err:
406 tfm = ERR_PTR(err);
407 out:
408 return tfm;
409 }
410 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
411
412 /*
413 * crypto_alloc_base - Locate algorithm and allocate transform
414 * @alg_name: Name of algorithm
415 * @type: Type of algorithm
416 * @mask: Mask for type comparison
417 *
418 * This function should not be used by new algorithm types.
419 * Plesae use crypto_alloc_tfm instead.
420 *
421 * crypto_alloc_base() will first attempt to locate an already loaded
422 * algorithm. If that fails and the kernel supports dynamically loadable
423 * modules, it will then attempt to load a module of the same name or
424 * alias. If that fails it will send a query to any loaded crypto manager
425 * to construct an algorithm on the fly. A refcount is grabbed on the
426 * algorithm which is then associated with the new transform.
427 *
428 * The returned transform is of a non-determinate type. Most people
429 * should use one of the more specific allocation functions such as
430 * crypto_alloc_blkcipher.
431 *
432 * In case of error the return value is an error pointer.
433 */
434 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
435 {
436 struct crypto_tfm *tfm;
437 int err;
438
439 for (;;) {
440 struct crypto_alg *alg;
441
442 alg = crypto_alg_mod_lookup(alg_name, type, mask);
443 if (IS_ERR(alg)) {
444 err = PTR_ERR(alg);
445 goto err;
446 }
447
448 tfm = __crypto_alloc_tfm(alg, type, mask);
449 if (!IS_ERR(tfm))
450 return tfm;
451
452 crypto_mod_put(alg);
453 err = PTR_ERR(tfm);
454
455 err:
456 if (err != -EAGAIN)
457 break;
458 if (signal_pending(current)) {
459 err = -EINTR;
460 break;
461 }
462 }
463
464 return ERR_PTR(err);
465 }
466 EXPORT_SYMBOL_GPL(crypto_alloc_base);
467
468 void *crypto_create_tfm(struct crypto_alg *alg,
469 const struct crypto_type *frontend)
470 {
471 char *mem;
472 struct crypto_tfm *tfm = NULL;
473 unsigned int tfmsize;
474 unsigned int total;
475 int err = -ENOMEM;
476
477 tfmsize = frontend->tfmsize;
478 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg, frontend);
479
480 mem = kzalloc(total, GFP_KERNEL);
481 if (mem == NULL)
482 goto out_err;
483
484 tfm = (struct crypto_tfm *)(mem + tfmsize);
485 tfm->__crt_alg = alg;
486
487 err = frontend->init_tfm(tfm, frontend);
488 if (err)
489 goto out_free_tfm;
490
491 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
492 goto cra_init_failed;
493
494 goto out;
495
496 cra_init_failed:
497 crypto_exit_ops(tfm);
498 out_free_tfm:
499 if (err == -EAGAIN)
500 crypto_shoot_alg(alg);
501 kfree(mem);
502 out_err:
503 mem = ERR_PTR(err);
504 out:
505 return mem;
506 }
507 EXPORT_SYMBOL_GPL(crypto_create_tfm);
508
509 /*
510 * crypto_alloc_tfm - Locate algorithm and allocate transform
511 * @alg_name: Name of algorithm
512 * @frontend: Frontend algorithm type
513 * @type: Type of algorithm
514 * @mask: Mask for type comparison
515 *
516 * crypto_alloc_tfm() will first attempt to locate an already loaded
517 * algorithm. If that fails and the kernel supports dynamically loadable
518 * modules, it will then attempt to load a module of the same name or
519 * alias. If that fails it will send a query to any loaded crypto manager
520 * to construct an algorithm on the fly. A refcount is grabbed on the
521 * algorithm which is then associated with the new transform.
522 *
523 * The returned transform is of a non-determinate type. Most people
524 * should use one of the more specific allocation functions such as
525 * crypto_alloc_blkcipher.
526 *
527 * In case of error the return value is an error pointer.
528 */
529 void *crypto_alloc_tfm(const char *alg_name,
530 const struct crypto_type *frontend, u32 type, u32 mask)
531 {
532 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask);
533 void *tfm;
534 int err;
535
536 type &= frontend->maskclear;
537 mask &= frontend->maskclear;
538 type |= frontend->type;
539 mask |= frontend->maskset;
540
541 lookup = frontend->lookup ?: crypto_alg_mod_lookup;
542
543 for (;;) {
544 struct crypto_alg *alg;
545
546 alg = lookup(alg_name, type, mask);
547 if (IS_ERR(alg)) {
548 err = PTR_ERR(alg);
549 goto err;
550 }
551
552 tfm = crypto_create_tfm(alg, frontend);
553 if (!IS_ERR(tfm))
554 return tfm;
555
556 crypto_mod_put(alg);
557 err = PTR_ERR(tfm);
558
559 err:
560 if (err != -EAGAIN)
561 break;
562 if (signal_pending(current)) {
563 err = -EINTR;
564 break;
565 }
566 }
567
568 return ERR_PTR(err);
569 }
570 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
571
572 /*
573 * crypto_destroy_tfm - Free crypto transform
574 * @mem: Start of tfm slab
575 * @tfm: Transform to free
576 *
577 * This function frees up the transform and any associated resources,
578 * then drops the refcount on the associated algorithm.
579 */
580 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
581 {
582 struct crypto_alg *alg;
583 int size;
584
585 if (unlikely(!mem))
586 return;
587
588 alg = tfm->__crt_alg;
589 size = ksize(mem);
590
591 if (!tfm->exit && alg->cra_exit)
592 alg->cra_exit(tfm);
593 crypto_exit_ops(tfm);
594 crypto_mod_put(alg);
595 memset(mem, 0, size);
596 kfree(mem);
597 }
598 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
599
600 int crypto_has_alg(const char *name, u32 type, u32 mask)
601 {
602 int ret = 0;
603 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
604
605 if (!IS_ERR(alg)) {
606 crypto_mod_put(alg);
607 ret = 1;
608 }
609
610 return ret;
611 }
612 EXPORT_SYMBOL_GPL(crypto_has_alg);
613
614 MODULE_DESCRIPTION("Cryptographic core API");
615 MODULE_LICENSE("GPL");
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