aboutsummaryrefslogtreecommitdiff
path: root/crypto/api.c
blob: bbc147cb5dec87affad82510412459c075056f86 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
/*
 * Scatterlist Cryptographic API.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
 * and Nettle, by Niels Möller.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include "internal.h"

LIST_HEAD(crypto_alg_list);
EXPORT_SYMBOL_GPL(crypto_alg_list);
DECLARE_RWSEM(crypto_alg_sem);
EXPORT_SYMBOL_GPL(crypto_alg_sem);

BLOCKING_NOTIFIER_HEAD(crypto_chain);
EXPORT_SYMBOL_GPL(crypto_chain);

static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);

struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
{
	return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
}
EXPORT_SYMBOL_GPL(crypto_mod_get);

void crypto_mod_put(struct crypto_alg *alg)
{
	struct module *module = alg->cra_module;

	crypto_alg_put(alg);
	module_put(module);
}
EXPORT_SYMBOL_GPL(crypto_mod_put);

static inline int crypto_is_test_larval(struct crypto_larval *larval)
{
	return larval->alg.cra_driver_name[0];
}

static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
					      u32 mask)
{
	struct crypto_alg *q, *alg = NULL;
	int best = -2;

	list_for_each_entry(q, &crypto_alg_list, cra_list) {
		int exact, fuzzy;

		if (crypto_is_moribund(q))
			continue;

		if ((q->cra_flags ^ type) & mask)
			continue;

		if (crypto_is_larval(q) &&
		    !crypto_is_test_larval((struct crypto_larval *)q) &&
		    ((struct crypto_larval *)q)->mask != mask)
			continue;

		exact = !strcmp(q->cra_driver_name, name);
		fuzzy = !strcmp(q->cra_name, name);
		if (!exact && !(fuzzy && q->cra_priority > best))
			continue;

		if (unlikely(!crypto_mod_get(q)))
			continue;

		best = q->cra_priority;
		if (alg)
			crypto_mod_put(alg);
		alg = q;

		if (exact)
			break;
	}

	return alg;
}

static void crypto_larval_destroy(struct crypto_alg *alg)
{
	struct crypto_larval *larval = (void *)alg;

	BUG_ON(!crypto_is_larval(alg));
	if (larval->adult)
		crypto_mod_put(larval->adult);
	kfree(larval);
}

struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
{
	struct crypto_larval *larval;

	larval = kzalloc(sizeof(*larval), GFP_KERNEL);
	if (!larval)
		return ERR_PTR(-ENOMEM);

	larval->mask = mask;
	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
	larval->alg.cra_priority = -1;
	larval->alg.cra_destroy = crypto_larval_destroy;

	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
	init_completion(&larval->completion);

	return larval;
}
EXPORT_SYMBOL_GPL(crypto_larval_alloc);

static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
					    u32 mask)
{
	struct crypto_alg *alg;
	struct crypto_larval *larval;

	larval = crypto_larval_alloc(name, type, mask);
	if (IS_ERR(larval))
		return ERR_CAST(larval);

	atomic_set(&larval->alg.cra_refcnt, 2);

	down_write(&crypto_alg_sem);
	alg = __crypto_alg_lookup(name, type, mask);
	if (!alg) {
		alg = &larval->alg;
		list_add(&alg->cra_list, &crypto_alg_list);
	}
	up_write(&crypto_alg_sem);

	if (alg != &larval->alg) {
		kfree(larval);
		if (crypto_is_larval(alg))
			alg = crypto_larval_wait(alg);
	}

	return alg;
}

void crypto_larval_kill(struct crypto_alg *alg)
{
	struct crypto_larval *larval = (void *)alg;

	down_write(&crypto_alg_sem);
	list_del(&alg->cra_list);
	up_write(&crypto_alg_sem);
	complete_all(&larval->completion);
	crypto_alg_put(alg);
}
EXPORT_SYMBOL_GPL(crypto_larval_kill);

static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
{
	struct crypto_larval *larval = (void *)alg;
	long timeout;

	timeout = wait_for_completion_killable_timeout(
		&larval->completion, 60 * HZ);

	alg = larval->adult;
	if (timeout < 0)
		alg = ERR_PTR(-EINTR);
	else if (!timeout)
		alg = ERR_PTR(-ETIMEDOUT);
	else if (!alg)
		alg = ERR_PTR(-ENOENT);
	else if (crypto_is_test_larval(larval) &&
		 !(alg->cra_flags & CRYPTO_ALG_TESTED))
		alg = ERR_PTR(-EAGAIN);
	else if (!crypto_mod_get(alg))
		alg = ERR_PTR(-EAGAIN);
	crypto_mod_put(&larval->alg);

	return alg;
}

struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
{
	struct crypto_alg *alg;

	down_read(&crypto_alg_sem);
	alg = __crypto_alg_lookup(name, type, mask);
	up_read(&crypto_alg_sem);

	return alg;
}
EXPORT_SYMBOL_GPL(crypto_alg_lookup);

struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
{
	struct crypto_alg *alg;

	if (!name)
		return ERR_PTR(-ENOENT);

	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
	type &= mask;

	alg = crypto_alg_lookup(name, type, mask);
	if (!alg) {
		request_module("crypto-%s", name);

		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
		      CRYPTO_ALG_NEED_FALLBACK))
			request_module("crypto-%s-all", name);

		alg = crypto_alg_lookup(name, type, mask);
	}

	if (alg)
		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;

	return crypto_larval_add(name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_larval_lookup);

int crypto_probing_notify(unsigned long val, void *v)
{
	int ok;

	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
	if (ok == NOTIFY_DONE) {
		request_module("cryptomgr");
		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
	}

	return ok;
}
EXPORT_SYMBOL_GPL(crypto_probing_notify);

struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
{
	struct crypto_alg *alg;
	struct crypto_alg *larval;
	int ok;

	if (!((type | mask) & CRYPTO_ALG_TESTED)) {
		type |= CRYPTO_ALG_TESTED;
		mask |= CRYPTO_ALG_TESTED;
	}

	/*
	 * If the internal flag is set for a cipher, require a caller to
	 * to invoke the cipher with the internal flag to use that cipher.
	 * Also, if a caller wants to allocate a cipher that may or may
	 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
	 * !(mask & CRYPTO_ALG_INTERNAL).
	 */
	if (!((type | mask) & CRYPTO_ALG_INTERNAL))
		mask |= CRYPTO_ALG_INTERNAL;

	larval = crypto_larval_lookup(name, type, mask);
	if (IS_ERR(larval) || !crypto_is_larval(larval))
		return larval;

	ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);

	if (ok == NOTIFY_STOP)
		alg = crypto_larval_wait(larval);
	else {
		crypto_mod_put(larval);
		alg = ERR_PTR(-ENOENT);
	}
	crypto_larval_kill(larval);
	return alg;
}
EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);

static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;

	if (type_obj)
		return type_obj->init(tfm, type, mask);

	switch (crypto_tfm_alg_type(tfm)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		return crypto_init_cipher_ops(tfm);

	case CRYPTO_ALG_TYPE_COMPRESS:
		return crypto_init_compress_ops(tfm);

	default:
		break;
	}

	BUG();
	return -EINVAL;
}

static void crypto_exit_ops(struct crypto_tfm *tfm)
{
	const struct crypto_type *type = tfm->__crt_alg->cra_type;

	if (type) {
		if (tfm->exit)
			tfm->exit(tfm);
		return;
	}

	switch (crypto_tfm_alg_type(tfm)) {
	case CRYPTO_ALG_TYPE_CIPHER:
		crypto_exit_cipher_ops(tfm);
		break;

	case CRYPTO_ALG_TYPE_COMPRESS:
		crypto_exit_compress_ops(tfm);
		break;

	default:
		BUG();
	}
}

static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
{
	const struct crypto_type *type_obj = alg->cra_type;
	unsigned int len;

	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
	if (type_obj)
		return len + type_obj->ctxsize(alg, type, mask);

	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
	default:
		BUG();

	case CRYPTO_ALG_TYPE_CIPHER:
		len += crypto_cipher_ctxsize(alg);
		break;

	case CRYPTO_ALG_TYPE_COMPRESS:
		len += crypto_compress_ctxsize(alg);
		break;
	}

	return len;
}

void crypto_shoot_alg(struct crypto_alg *alg)
{
	down_write(&crypto_alg_sem);
	alg->cra_flags |= CRYPTO_ALG_DYING;
	up_write(&crypto_alg_sem);
}
EXPORT_SYMBOL_GPL(crypto_shoot_alg);

struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
				      u32 mask)
{
	struct crypto_tfm *tfm = NULL;
	unsigned int tfm_size;
	int err = -ENOMEM;

	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
	tfm = kzalloc(tfm_size, GFP_KERNEL);
	if (tfm == NULL)
		goto out_err;

	tfm->__crt_alg = alg;

	err = crypto_init_ops(tfm, type, mask);
	if (err)
		goto out_free_tfm;

	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
		goto cra_init_failed;

	goto out;

cra_init_failed:
	crypto_exit_ops(tfm);
out_free_tfm:
	if (err == -EAGAIN)
		crypto_shoot_alg(alg);
	kfree(tfm);
out_err:
	tfm = ERR_PTR(err);
out:
	return tfm;
}
EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);

/*
 *	crypto_alloc_base - Locate algorithm and allocate transform
 *	@alg_name: Name of algorithm
 *	@type: Type of algorithm
 *	@mask: Mask for type comparison
 *
 *	This function should not be used by new algorithm types.
 *	Please use crypto_alloc_tfm instead.
 *
 *	crypto_alloc_base() will first attempt to locate an already loaded
 *	algorithm.  If that fails and the kernel supports dynamically loadable
 *	modules, it will then attempt to load a module of the same name or
 *	alias.  If that fails it will send a query to any loaded crypto manager
 *	to construct an algorithm on the fly.  A refcount is grabbed on the
 *	algorithm which is then associated with the new transform.
 *
 *	The returned transform is of a non-determinate type.  Most people
 *	should use one of the more specific allocation functions such as
 *	crypto_alloc_blkcipher.
 *
 *	In case of error the return value is an error pointer.
 */
struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
{
	struct crypto_tfm *tfm;
	int err;

	for (;;) {
		struct crypto_alg *alg;

		alg = crypto_alg_mod_lookup(alg_name, type, mask);
		if (IS_ERR(alg)) {
			err = PTR_ERR(alg);
			goto err;
		}

		tfm = __crypto_alloc_tfm(alg, type, mask);
		if (!IS_ERR(tfm))
			return tfm;

		crypto_mod_put(alg);
		err = PTR_ERR(tfm);

err:
		if (err != -EAGAIN)
			break;
		if (fatal_signal_pending(current)) {
			err = -EINTR;
			break;
		}
	}

	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_base);

void *crypto_create_tfm(struct crypto_alg *alg,
			const struct crypto_type *frontend)
{
	char *mem;
	struct crypto_tfm *tfm = NULL;
	unsigned int tfmsize;
	unsigned int total;
	int err = -ENOMEM;

	tfmsize = frontend->tfmsize;
	total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);

	mem = kzalloc(total, GFP_KERNEL);
	if (mem == NULL)
		goto out_err;

	tfm = (struct crypto_tfm *)(mem + tfmsize);
	tfm->__crt_alg = alg;

	err = frontend->init_tfm(tfm);
	if (err)
		goto out_free_tfm;

	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
		goto cra_init_failed;

	goto out;

cra_init_failed:
	crypto_exit_ops(tfm);
out_free_tfm:
	if (err == -EAGAIN)
		crypto_shoot_alg(alg);
	kfree(mem);
out_err:
	mem = ERR_PTR(err);
out:
	return mem;
}
EXPORT_SYMBOL_GPL(crypto_create_tfm);

struct crypto_alg *crypto_find_alg(const char *alg_name,
				   const struct crypto_type *frontend,
				   u32 type, u32 mask)
{
	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
		crypto_alg_mod_lookup;

	if (frontend) {
		type &= frontend->maskclear;
		mask &= frontend->maskclear;
		type |= frontend->type;
		mask |= frontend->maskset;

		if (frontend->lookup)
			lookup = frontend->lookup;
	}

	return lookup(alg_name, type, mask);
}
EXPORT_SYMBOL_GPL(crypto_find_alg);

/*
 *	crypto_alloc_tfm - Locate algorithm and allocate transform
 *	@alg_name: Name of algorithm
 *	@frontend: Frontend algorithm type
 *	@type: Type of algorithm
 *	@mask: Mask for type comparison
 *
 *	crypto_alloc_tfm() will first attempt to locate an already loaded
 *	algorithm.  If that fails and the kernel supports dynamically loadable
 *	modules, it will then attempt to load a module of the same name or
 *	alias.  If that fails it will send a query to any loaded crypto manager
 *	to construct an algorithm on the fly.  A refcount is grabbed on the
 *	algorithm which is then associated with the new transform.
 *
 *	The returned transform is of a non-determinate type.  Most people
 *	should use one of the more specific allocation functions such as
 *	crypto_alloc_blkcipher.
 *
 *	In case of error the return value is an error pointer.
 */
void *crypto_alloc_tfm(const char *alg_name,
		       const struct crypto_type *frontend, u32 type, u32 mask)
{
	void *tfm;
	int err;

	for (;;) {
		struct crypto_alg *alg;

		alg = crypto_find_alg(alg_name, frontend, type, mask);
		if (IS_ERR(alg)) {
			err = PTR_ERR(alg);
			goto err;
		}

		tfm = crypto_create_tfm(alg, frontend);
		if (!IS_ERR(tfm))
			return tfm;

		crypto_mod_put(alg);
		err = PTR_ERR(tfm);

err:
		if (err != -EAGAIN)
			break;
		if (fatal_signal_pending(current)) {
			err = -EINTR;
			break;
		}
	}

	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(crypto_alloc_tfm);

/*
 *	crypto_destroy_tfm - Free crypto transform
 *	@mem: Start of tfm slab
 *	@tfm: Transform to free
 *
 *	This function frees up the transform and any associated resources,
 *	then drops the refcount on the associated algorithm.
 */
void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
{
	struct crypto_alg *alg;

	if (unlikely(!mem))
		return;

	alg = tfm->__crt_alg;

	if (!tfm->exit && alg->cra_exit)
		alg->cra_exit(tfm);
	crypto_exit_ops(tfm);
	crypto_mod_put(alg);
	kzfree(mem);
}
EXPORT_SYMBOL_GPL(crypto_destroy_tfm);

int crypto_has_alg(const char *name, u32 type, u32 mask)
{
	int ret = 0;
	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);

	if (!IS_ERR(alg)) {
		crypto_mod_put(alg);
		ret = 1;
	}

	return ret;
}
EXPORT_SYMBOL_GPL(crypto_has_alg);

MODULE_DESCRIPTION("Cryptographic core API");
MODULE_LICENSE("GPL");