projects/linux·blob v3.14 · refs

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