ip6_tunnel: add collect_md mode to IPv6 tunnels
[linux-2.6/btrfs-unstable.git] / crypto / api.c
blobbbc147cb5dec87affad82510412459c075056f86
1 /*
2 * Scatterlist Cryptographic API.
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>
8 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
9 * and Nettle, by Niels Möller.
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.
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"
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);
34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
35 EXPORT_SYMBOL_GPL(crypto_chain);
37 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
39 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
41 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
43 EXPORT_SYMBOL_GPL(crypto_mod_get);
45 void crypto_mod_put(struct crypto_alg *alg)
47 struct module *module = alg->cra_module;
49 crypto_alg_put(alg);
50 module_put(module);
52 EXPORT_SYMBOL_GPL(crypto_mod_put);
54 static inline int crypto_is_test_larval(struct crypto_larval *larval)
56 return larval->alg.cra_driver_name[0];
59 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
60 u32 mask)
62 struct crypto_alg *q, *alg = NULL;
63 int best = -2;
65 list_for_each_entry(q, &crypto_alg_list, cra_list) {
66 int exact, fuzzy;
68 if (crypto_is_moribund(q))
69 continue;
71 if ((q->cra_flags ^ type) & mask)
72 continue;
74 if (crypto_is_larval(q) &&
75 !crypto_is_test_larval((struct crypto_larval *)q) &&
76 ((struct crypto_larval *)q)->mask != mask)
77 continue;
79 exact = !strcmp(q->cra_driver_name, name);
80 fuzzy = !strcmp(q->cra_name, name);
81 if (!exact && !(fuzzy && q->cra_priority > best))
82 continue;
84 if (unlikely(!crypto_mod_get(q)))
85 continue;
87 best = q->cra_priority;
88 if (alg)
89 crypto_mod_put(alg);
90 alg = q;
92 if (exact)
93 break;
96 return alg;
99 static void crypto_larval_destroy(struct crypto_alg *alg)
101 struct crypto_larval *larval = (void *)alg;
103 BUG_ON(!crypto_is_larval(alg));
104 if (larval->adult)
105 crypto_mod_put(larval->adult);
106 kfree(larval);
109 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
111 struct crypto_larval *larval;
113 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
114 if (!larval)
115 return ERR_PTR(-ENOMEM);
117 larval->mask = mask;
118 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
119 larval->alg.cra_priority = -1;
120 larval->alg.cra_destroy = crypto_larval_destroy;
122 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
123 init_completion(&larval->completion);
125 return larval;
127 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
129 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
130 u32 mask)
132 struct crypto_alg *alg;
133 struct crypto_larval *larval;
135 larval = crypto_larval_alloc(name, type, mask);
136 if (IS_ERR(larval))
137 return ERR_CAST(larval);
139 atomic_set(&larval->alg.cra_refcnt, 2);
141 down_write(&crypto_alg_sem);
142 alg = __crypto_alg_lookup(name, type, mask);
143 if (!alg) {
144 alg = &larval->alg;
145 list_add(&alg->cra_list, &crypto_alg_list);
147 up_write(&crypto_alg_sem);
149 if (alg != &larval->alg) {
150 kfree(larval);
151 if (crypto_is_larval(alg))
152 alg = crypto_larval_wait(alg);
155 return alg;
158 void crypto_larval_kill(struct crypto_alg *alg)
160 struct crypto_larval *larval = (void *)alg;
162 down_write(&crypto_alg_sem);
163 list_del(&alg->cra_list);
164 up_write(&crypto_alg_sem);
165 complete_all(&larval->completion);
166 crypto_alg_put(alg);
168 EXPORT_SYMBOL_GPL(crypto_larval_kill);
170 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
172 struct crypto_larval *larval = (void *)alg;
173 long timeout;
175 timeout = wait_for_completion_killable_timeout(
176 &larval->completion, 60 * HZ);
178 alg = larval->adult;
179 if (timeout < 0)
180 alg = ERR_PTR(-EINTR);
181 else if (!timeout)
182 alg = ERR_PTR(-ETIMEDOUT);
183 else if (!alg)
184 alg = ERR_PTR(-ENOENT);
185 else if (crypto_is_test_larval(larval) &&
186 !(alg->cra_flags & CRYPTO_ALG_TESTED))
187 alg = ERR_PTR(-EAGAIN);
188 else if (!crypto_mod_get(alg))
189 alg = ERR_PTR(-EAGAIN);
190 crypto_mod_put(&larval->alg);
192 return alg;
195 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
197 struct crypto_alg *alg;
199 down_read(&crypto_alg_sem);
200 alg = __crypto_alg_lookup(name, type, mask);
201 up_read(&crypto_alg_sem);
203 return alg;
205 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
207 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
209 struct crypto_alg *alg;
211 if (!name)
212 return ERR_PTR(-ENOENT);
214 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
215 type &= mask;
217 alg = crypto_alg_lookup(name, type, mask);
218 if (!alg) {
219 request_module("crypto-%s", name);
221 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
222 CRYPTO_ALG_NEED_FALLBACK))
223 request_module("crypto-%s-all", name);
225 alg = crypto_alg_lookup(name, type, mask);
228 if (alg)
229 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
231 return crypto_larval_add(name, type, mask);
233 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
235 int crypto_probing_notify(unsigned long val, void *v)
237 int ok;
239 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
240 if (ok == NOTIFY_DONE) {
241 request_module("cryptomgr");
242 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
245 return ok;
247 EXPORT_SYMBOL_GPL(crypto_probing_notify);
249 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
251 struct crypto_alg *alg;
252 struct crypto_alg *larval;
253 int ok;
255 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
256 type |= CRYPTO_ALG_TESTED;
257 mask |= CRYPTO_ALG_TESTED;
261 * If the internal flag is set for a cipher, require a caller to
262 * to invoke the cipher with the internal flag to use that cipher.
263 * Also, if a caller wants to allocate a cipher that may or may
264 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
265 * !(mask & CRYPTO_ALG_INTERNAL).
267 if (!((type | mask) & CRYPTO_ALG_INTERNAL))
268 mask |= CRYPTO_ALG_INTERNAL;
270 larval = crypto_larval_lookup(name, type, mask);
271 if (IS_ERR(larval) || !crypto_is_larval(larval))
272 return larval;
274 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
276 if (ok == NOTIFY_STOP)
277 alg = crypto_larval_wait(larval);
278 else {
279 crypto_mod_put(larval);
280 alg = ERR_PTR(-ENOENT);
282 crypto_larval_kill(larval);
283 return alg;
285 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
287 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
289 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
291 if (type_obj)
292 return type_obj->init(tfm, type, mask);
294 switch (crypto_tfm_alg_type(tfm)) {
295 case CRYPTO_ALG_TYPE_CIPHER:
296 return crypto_init_cipher_ops(tfm);
298 case CRYPTO_ALG_TYPE_COMPRESS:
299 return crypto_init_compress_ops(tfm);
301 default:
302 break;
305 BUG();
306 return -EINVAL;
309 static void crypto_exit_ops(struct crypto_tfm *tfm)
311 const struct crypto_type *type = tfm->__crt_alg->cra_type;
313 if (type) {
314 if (tfm->exit)
315 tfm->exit(tfm);
316 return;
319 switch (crypto_tfm_alg_type(tfm)) {
320 case CRYPTO_ALG_TYPE_CIPHER:
321 crypto_exit_cipher_ops(tfm);
322 break;
324 case CRYPTO_ALG_TYPE_COMPRESS:
325 crypto_exit_compress_ops(tfm);
326 break;
328 default:
329 BUG();
333 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
335 const struct crypto_type *type_obj = alg->cra_type;
336 unsigned int len;
338 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
339 if (type_obj)
340 return len + type_obj->ctxsize(alg, type, mask);
342 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
343 default:
344 BUG();
346 case CRYPTO_ALG_TYPE_CIPHER:
347 len += crypto_cipher_ctxsize(alg);
348 break;
350 case CRYPTO_ALG_TYPE_COMPRESS:
351 len += crypto_compress_ctxsize(alg);
352 break;
355 return len;
358 void crypto_shoot_alg(struct crypto_alg *alg)
360 down_write(&crypto_alg_sem);
361 alg->cra_flags |= CRYPTO_ALG_DYING;
362 up_write(&crypto_alg_sem);
364 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
366 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
367 u32 mask)
369 struct crypto_tfm *tfm = NULL;
370 unsigned int tfm_size;
371 int err = -ENOMEM;
373 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
374 tfm = kzalloc(tfm_size, GFP_KERNEL);
375 if (tfm == NULL)
376 goto out_err;
378 tfm->__crt_alg = alg;
380 err = crypto_init_ops(tfm, type, mask);
381 if (err)
382 goto out_free_tfm;
384 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
385 goto cra_init_failed;
387 goto out;
389 cra_init_failed:
390 crypto_exit_ops(tfm);
391 out_free_tfm:
392 if (err == -EAGAIN)
393 crypto_shoot_alg(alg);
394 kfree(tfm);
395 out_err:
396 tfm = ERR_PTR(err);
397 out:
398 return tfm;
400 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
403 * crypto_alloc_base - Locate algorithm and allocate transform
404 * @alg_name: Name of algorithm
405 * @type: Type of algorithm
406 * @mask: Mask for type comparison
408 * This function should not be used by new algorithm types.
409 * Please use crypto_alloc_tfm instead.
411 * crypto_alloc_base() will first attempt to locate an already loaded
412 * algorithm. If that fails and the kernel supports dynamically loadable
413 * modules, it will then attempt to load a module of the same name or
414 * alias. If that fails it will send a query to any loaded crypto manager
415 * to construct an algorithm on the fly. A refcount is grabbed on the
416 * algorithm which is then associated with the new transform.
418 * The returned transform is of a non-determinate type. Most people
419 * should use one of the more specific allocation functions such as
420 * crypto_alloc_blkcipher.
422 * In case of error the return value is an error pointer.
424 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
426 struct crypto_tfm *tfm;
427 int err;
429 for (;;) {
430 struct crypto_alg *alg;
432 alg = crypto_alg_mod_lookup(alg_name, type, mask);
433 if (IS_ERR(alg)) {
434 err = PTR_ERR(alg);
435 goto err;
438 tfm = __crypto_alloc_tfm(alg, type, mask);
439 if (!IS_ERR(tfm))
440 return tfm;
442 crypto_mod_put(alg);
443 err = PTR_ERR(tfm);
445 err:
446 if (err != -EAGAIN)
447 break;
448 if (fatal_signal_pending(current)) {
449 err = -EINTR;
450 break;
454 return ERR_PTR(err);
456 EXPORT_SYMBOL_GPL(crypto_alloc_base);
458 void *crypto_create_tfm(struct crypto_alg *alg,
459 const struct crypto_type *frontend)
461 char *mem;
462 struct crypto_tfm *tfm = NULL;
463 unsigned int tfmsize;
464 unsigned int total;
465 int err = -ENOMEM;
467 tfmsize = frontend->tfmsize;
468 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
470 mem = kzalloc(total, GFP_KERNEL);
471 if (mem == NULL)
472 goto out_err;
474 tfm = (struct crypto_tfm *)(mem + tfmsize);
475 tfm->__crt_alg = alg;
477 err = frontend->init_tfm(tfm);
478 if (err)
479 goto out_free_tfm;
481 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
482 goto cra_init_failed;
484 goto out;
486 cra_init_failed:
487 crypto_exit_ops(tfm);
488 out_free_tfm:
489 if (err == -EAGAIN)
490 crypto_shoot_alg(alg);
491 kfree(mem);
492 out_err:
493 mem = ERR_PTR(err);
494 out:
495 return mem;
497 EXPORT_SYMBOL_GPL(crypto_create_tfm);
499 struct crypto_alg *crypto_find_alg(const char *alg_name,
500 const struct crypto_type *frontend,
501 u32 type, u32 mask)
503 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
504 crypto_alg_mod_lookup;
506 if (frontend) {
507 type &= frontend->maskclear;
508 mask &= frontend->maskclear;
509 type |= frontend->type;
510 mask |= frontend->maskset;
512 if (frontend->lookup)
513 lookup = frontend->lookup;
516 return lookup(alg_name, type, mask);
518 EXPORT_SYMBOL_GPL(crypto_find_alg);
521 * crypto_alloc_tfm - Locate algorithm and allocate transform
522 * @alg_name: Name of algorithm
523 * @frontend: Frontend algorithm type
524 * @type: Type of algorithm
525 * @mask: Mask for type comparison
527 * crypto_alloc_tfm() will first attempt to locate an already loaded
528 * algorithm. If that fails and the kernel supports dynamically loadable
529 * modules, it will then attempt to load a module of the same name or
530 * alias. If that fails it will send a query to any loaded crypto manager
531 * to construct an algorithm on the fly. A refcount is grabbed on the
532 * algorithm which is then associated with the new transform.
534 * The returned transform is of a non-determinate type. Most people
535 * should use one of the more specific allocation functions such as
536 * crypto_alloc_blkcipher.
538 * In case of error the return value is an error pointer.
540 void *crypto_alloc_tfm(const char *alg_name,
541 const struct crypto_type *frontend, u32 type, u32 mask)
543 void *tfm;
544 int err;
546 for (;;) {
547 struct crypto_alg *alg;
549 alg = crypto_find_alg(alg_name, frontend, type, mask);
550 if (IS_ERR(alg)) {
551 err = PTR_ERR(alg);
552 goto err;
555 tfm = crypto_create_tfm(alg, frontend);
556 if (!IS_ERR(tfm))
557 return tfm;
559 crypto_mod_put(alg);
560 err = PTR_ERR(tfm);
562 err:
563 if (err != -EAGAIN)
564 break;
565 if (fatal_signal_pending(current)) {
566 err = -EINTR;
567 break;
571 return ERR_PTR(err);
573 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
576 * crypto_destroy_tfm - Free crypto transform
577 * @mem: Start of tfm slab
578 * @tfm: Transform to free
580 * This function frees up the transform and any associated resources,
581 * then drops the refcount on the associated algorithm.
583 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
585 struct crypto_alg *alg;
587 if (unlikely(!mem))
588 return;
590 alg = tfm->__crt_alg;
592 if (!tfm->exit && alg->cra_exit)
593 alg->cra_exit(tfm);
594 crypto_exit_ops(tfm);
595 crypto_mod_put(alg);
596 kzfree(mem);
598 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
600 int crypto_has_alg(const char *name, u32 type, u32 mask)
602 int ret = 0;
603 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
605 if (!IS_ERR(alg)) {
606 crypto_mod_put(alg);
607 ret = 1;
610 return ret;
612 EXPORT_SYMBOL_GPL(crypto_has_alg);
614 MODULE_DESCRIPTION("Cryptographic core API");
615 MODULE_LICENSE("GPL");