projects/linux·blob v4.11 · 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/signal.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_killable_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 type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
215 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
216
217 alg = crypto_alg_lookup(name, type, mask);
218 if (!alg) {
219 request_module("crypto-%s", name);
220
221 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
222 CRYPTO_ALG_NEED_FALLBACK))
223 request_module("crypto-%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 /*
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).
266 */
267 if (!((type | mask) & CRYPTO_ALG_INTERNAL))
268 mask |= CRYPTO_ALG_INTERNAL;
269
270 larval = crypto_larval_lookup(name, type, mask);
271 if (IS_ERR(larval) || !crypto_is_larval(larval))
272 return larval;
273
274 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
275
276 if (ok == NOTIFY_STOP)
277 alg = crypto_larval_wait(larval);
278 else {
279 crypto_mod_put(larval);
280 alg = ERR_PTR(-ENOENT);
281 }
282 crypto_larval_kill(larval);
283 return alg;
284}
285EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
286
287static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
288{
289 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
290
291 if (type_obj)
292 return type_obj->init(tfm, type, mask);
293
294 switch (crypto_tfm_alg_type(tfm)) {
295 case CRYPTO_ALG_TYPE_CIPHER:
296 return crypto_init_cipher_ops(tfm);
297
298 case CRYPTO_ALG_TYPE_COMPRESS:
299 return crypto_init_compress_ops(tfm);
300
301 default:
302 break;
303 }
304
305 BUG();
306 return -EINVAL;
307}
308
309static void crypto_exit_ops(struct crypto_tfm *tfm)
310{
311 const struct crypto_type *type = tfm->__crt_alg->cra_type;
312
313 if (type && tfm->exit)
314 tfm->exit(tfm);
315}
316
317static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
318{
319 const struct crypto_type *type_obj = alg->cra_type;
320 unsigned int len;
321
322 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
323 if (type_obj)
324 return len + type_obj->ctxsize(alg, type, mask);
325
326 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
327 default:
328 BUG();
329
330 case CRYPTO_ALG_TYPE_CIPHER:
331 len += crypto_cipher_ctxsize(alg);
332 break;
333
334 case CRYPTO_ALG_TYPE_COMPRESS:
335 len += crypto_compress_ctxsize(alg);
336 break;
337 }
338
339 return len;
340}
341
342void crypto_shoot_alg(struct crypto_alg *alg)
343{
344 down_write(&crypto_alg_sem);
345 alg->cra_flags |= CRYPTO_ALG_DYING;
346 up_write(&crypto_alg_sem);
347}
348EXPORT_SYMBOL_GPL(crypto_shoot_alg);
349
350struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
351 u32 mask)
352{
353 struct crypto_tfm *tfm = NULL;
354 unsigned int tfm_size;
355 int err = -ENOMEM;
356
357 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
358 tfm = kzalloc(tfm_size, GFP_KERNEL);
359 if (tfm == NULL)
360 goto out_err;
361
362 tfm->__crt_alg = alg;
363
364 err = crypto_init_ops(tfm, type, mask);
365 if (err)
366 goto out_free_tfm;
367
368 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
369 goto cra_init_failed;
370
371 goto out;
372
373cra_init_failed:
374 crypto_exit_ops(tfm);
375out_free_tfm:
376 if (err == -EAGAIN)
377 crypto_shoot_alg(alg);
378 kfree(tfm);
379out_err:
380 tfm = ERR_PTR(err);
381out:
382 return tfm;
383}
384EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
385
386/*
387 * crypto_alloc_base - Locate algorithm and allocate transform
388 * @alg_name: Name of algorithm
389 * @type: Type of algorithm
390 * @mask: Mask for type comparison
391 *
392 * This function should not be used by new algorithm types.
393 * Please use crypto_alloc_tfm instead.
394 *
395 * crypto_alloc_base() will first attempt to locate an already loaded
396 * algorithm. If that fails and the kernel supports dynamically loadable
397 * modules, it will then attempt to load a module of the same name or
398 * alias. If that fails it will send a query to any loaded crypto manager
399 * to construct an algorithm on the fly. A refcount is grabbed on the
400 * algorithm which is then associated with the new transform.
401 *
402 * The returned transform is of a non-determinate type. Most people
403 * should use one of the more specific allocation functions such as
404 * crypto_alloc_blkcipher.
405 *
406 * In case of error the return value is an error pointer.
407 */
408struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
409{
410 struct crypto_tfm *tfm;
411 int err;
412
413 for (;;) {
414 struct crypto_alg *alg;
415
416 alg = crypto_alg_mod_lookup(alg_name, type, mask);
417 if (IS_ERR(alg)) {
418 err = PTR_ERR(alg);
419 goto err;
420 }
421
422 tfm = __crypto_alloc_tfm(alg, type, mask);
423 if (!IS_ERR(tfm))
424 return tfm;
425
426 crypto_mod_put(alg);
427 err = PTR_ERR(tfm);
428
429err:
430 if (err != -EAGAIN)
431 break;
432 if (fatal_signal_pending(current)) {
433 err = -EINTR;
434 break;
435 }
436 }
437
438 return ERR_PTR(err);
439}
440EXPORT_SYMBOL_GPL(crypto_alloc_base);
441
442void *crypto_create_tfm(struct crypto_alg *alg,
443 const struct crypto_type *frontend)
444{
445 char *mem;
446 struct crypto_tfm *tfm = NULL;
447 unsigned int tfmsize;
448 unsigned int total;
449 int err = -ENOMEM;
450
451 tfmsize = frontend->tfmsize;
452 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
453
454 mem = kzalloc(total, GFP_KERNEL);
455 if (mem == NULL)
456 goto out_err;
457
458 tfm = (struct crypto_tfm *)(mem + tfmsize);
459 tfm->__crt_alg = alg;
460
461 err = frontend->init_tfm(tfm);
462 if (err)
463 goto out_free_tfm;
464
465 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
466 goto cra_init_failed;
467
468 goto out;
469
470cra_init_failed:
471 crypto_exit_ops(tfm);
472out_free_tfm:
473 if (err == -EAGAIN)
474 crypto_shoot_alg(alg);
475 kfree(mem);
476out_err:
477 mem = ERR_PTR(err);
478out:
479 return mem;
480}
481EXPORT_SYMBOL_GPL(crypto_create_tfm);
482
483struct crypto_alg *crypto_find_alg(const char *alg_name,
484 const struct crypto_type *frontend,
485 u32 type, u32 mask)
486{
487 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
488 crypto_alg_mod_lookup;
489
490 if (frontend) {
491 type &= frontend->maskclear;
492 mask &= frontend->maskclear;
493 type |= frontend->type;
494 mask |= frontend->maskset;
495
496 if (frontend->lookup)
497 lookup = frontend->lookup;
498 }
499
500 return lookup(alg_name, type, mask);
501}
502EXPORT_SYMBOL_GPL(crypto_find_alg);
503
504/*
505 * crypto_alloc_tfm - Locate algorithm and allocate transform
506 * @alg_name: Name of algorithm
507 * @frontend: Frontend algorithm type
508 * @type: Type of algorithm
509 * @mask: Mask for type comparison
510 *
511 * crypto_alloc_tfm() will first attempt to locate an already loaded
512 * algorithm. If that fails and the kernel supports dynamically loadable
513 * modules, it will then attempt to load a module of the same name or
514 * alias. If that fails it will send a query to any loaded crypto manager
515 * to construct an algorithm on the fly. A refcount is grabbed on the
516 * algorithm which is then associated with the new transform.
517 *
518 * The returned transform is of a non-determinate type. Most people
519 * should use one of the more specific allocation functions such as
520 * crypto_alloc_blkcipher.
521 *
522 * In case of error the return value is an error pointer.
523 */
524void *crypto_alloc_tfm(const char *alg_name,
525 const struct crypto_type *frontend, u32 type, u32 mask)
526{
527 void *tfm;
528 int err;
529
530 for (;;) {
531 struct crypto_alg *alg;
532
533 alg = crypto_find_alg(alg_name, frontend, type, mask);
534 if (IS_ERR(alg)) {
535 err = PTR_ERR(alg);
536 goto err;
537 }
538
539 tfm = crypto_create_tfm(alg, frontend);
540 if (!IS_ERR(tfm))
541 return tfm;
542
543 crypto_mod_put(alg);
544 err = PTR_ERR(tfm);
545
546err:
547 if (err != -EAGAIN)
548 break;
549 if (fatal_signal_pending(current)) {
550 err = -EINTR;
551 break;
552 }
553 }
554
555 return ERR_PTR(err);
556}
557EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
558
559/*
560 * crypto_destroy_tfm - Free crypto transform
561 * @mem: Start of tfm slab
562 * @tfm: Transform to free
563 *
564 * This function frees up the transform and any associated resources,
565 * then drops the refcount on the associated algorithm.
566 */
567void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
568{
569 struct crypto_alg *alg;
570
571 if (unlikely(!mem))
572 return;
573
574 alg = tfm->__crt_alg;
575
576 if (!tfm->exit && alg->cra_exit)
577 alg->cra_exit(tfm);
578 crypto_exit_ops(tfm);
579 crypto_mod_put(alg);
580 kzfree(mem);
581}
582EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
583
584int crypto_has_alg(const char *name, u32 type, u32 mask)
585{
586 int ret = 0;
587 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
588
589 if (!IS_ERR(alg)) {
590 crypto_mod_put(alg);
591 ret = 1;
592 }
593
594 return ret;
595}
596EXPORT_SYMBOL_GPL(crypto_has_alg);
597
598MODULE_DESCRIPTION("Cryptographic core API");
599MODULE_LICENSE("GPL");