Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  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
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * RSA padding templates.
 *
 * Copyright (c) 2015  Intel Corporation
 */

#include <crypto/algapi.h>
#include <crypto/akcipher.h>
#include <crypto/internal/akcipher.h>
#include <crypto/internal/rsa.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/random.h>

/*
 * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
 */
static const u8 rsa_digest_info_md5[] = {
	0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
	0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
	0x05, 0x00, 0x04, 0x10
};

static const u8 rsa_digest_info_sha1[] = {
	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
	0x2b, 0x0e, 0x03, 0x02, 0x1a,
	0x05, 0x00, 0x04, 0x14
};

static const u8 rsa_digest_info_rmd160[] = {
	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
	0x2b, 0x24, 0x03, 0x02, 0x01,
	0x05, 0x00, 0x04, 0x14
};

static const u8 rsa_digest_info_sha224[] = {
	0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
	0x05, 0x00, 0x04, 0x1c
};

static const u8 rsa_digest_info_sha256[] = {
	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
	0x05, 0x00, 0x04, 0x20
};

static const u8 rsa_digest_info_sha384[] = {
	0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
	0x05, 0x00, 0x04, 0x30
};

static const u8 rsa_digest_info_sha512[] = {
	0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
	0x05, 0x00, 0x04, 0x40
};

static const struct rsa_asn1_template {
	const char	*name;
	const u8	*data;
	size_t		size;
} rsa_asn1_templates[] = {
#define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
	_(md5),
	_(sha1),
	_(rmd160),
	_(sha256),
	_(sha384),
	_(sha512),
	_(sha224),
	{ NULL }
#undef _
};

static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
{
	const struct rsa_asn1_template *p;

	for (p = rsa_asn1_templates; p->name; p++)
		if (strcmp(name, p->name) == 0)
			return p;
	return NULL;
}

struct pkcs1pad_ctx {
	struct crypto_akcipher *child;
	unsigned int key_size;
};

struct pkcs1pad_inst_ctx {
	struct crypto_akcipher_spawn spawn;
	const struct rsa_asn1_template *digest_info;
};

struct pkcs1pad_request {
	struct scatterlist in_sg[2], out_sg[1];
	uint8_t *in_buf, *out_buf;
	struct akcipher_request child_req;
};

static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
		unsigned int keylen)
{
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	int err;

	ctx->key_size = 0;

	err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
	if (err)
		return err;

	/* Find out new modulus size from rsa implementation */
	err = crypto_akcipher_maxsize(ctx->child);
	if (err > PAGE_SIZE)
		return -ENOTSUPP;

	ctx->key_size = err;
	return 0;
}

static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
		unsigned int keylen)
{
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	int err;

	ctx->key_size = 0;

	err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
	if (err)
		return err;

	/* Find out new modulus size from rsa implementation */
	err = crypto_akcipher_maxsize(ctx->child);
	if (err > PAGE_SIZE)
		return -ENOTSUPP;

	ctx->key_size = err;
	return 0;
}

static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
{
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);

	/*
	 * The maximum destination buffer size for the encrypt/sign operations
	 * will be the same as for RSA, even though it's smaller for
	 * decrypt/verify.
	 */

	return ctx->key_size;
}

static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
		struct scatterlist *next)
{
	int nsegs = next ? 2 : 1;

	sg_init_table(sg, nsegs);
	sg_set_buf(sg, buf, len);

	if (next)
		sg_chain(sg, nsegs, next);
}

static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	unsigned int pad_len;
	unsigned int len;
	u8 *out_buf;

	if (err)
		goto out;

	len = req_ctx->child_req.dst_len;
	pad_len = ctx->key_size - len;

	/* Four billion to one */
	if (likely(!pad_len))
		goto out;

	out_buf = kzalloc(ctx->key_size, GFP_KERNEL);
	err = -ENOMEM;
	if (!out_buf)
		goto out;

	sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
			  out_buf + pad_len, len);
	sg_copy_from_buffer(req->dst,
			    sg_nents_for_len(req->dst, ctx->key_size),
			    out_buf, ctx->key_size);
	kzfree(out_buf);

out:
	req->dst_len = ctx->key_size;

	kfree(req_ctx->in_buf);

	return err;
}

static void pkcs1pad_encrypt_sign_complete_cb(
		struct crypto_async_request *child_async_req, int err)
{
	struct akcipher_request *req = child_async_req->data;
	struct crypto_async_request async_req;

	if (err == -EINPROGRESS)
		return;

	async_req.data = req->base.data;
	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
	async_req.flags = child_async_req->flags;
	req->base.complete(&async_req,
			pkcs1pad_encrypt_sign_complete(req, err));
}

static int pkcs1pad_encrypt(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	int err;
	unsigned int i, ps_end;

	if (!ctx->key_size)
		return -EINVAL;

	if (req->src_len > ctx->key_size - 11)
		return -EOVERFLOW;

	if (req->dst_len < ctx->key_size) {
		req->dst_len = ctx->key_size;
		return -EOVERFLOW;
	}

	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
				  GFP_KERNEL);
	if (!req_ctx->in_buf)
		return -ENOMEM;

	ps_end = ctx->key_size - req->src_len - 2;
	req_ctx->in_buf[0] = 0x02;
	for (i = 1; i < ps_end; i++)
		req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
	req_ctx->in_buf[ps_end] = 0x00;

	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
			ctx->key_size - 1 - req->src_len, req->src);

	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
			pkcs1pad_encrypt_sign_complete_cb, req);

	/* Reuse output buffer */
	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
				   req->dst, ctx->key_size - 1, req->dst_len);

	err = crypto_akcipher_encrypt(&req_ctx->child_req);
	if (err != -EINPROGRESS && err != -EBUSY)
		return pkcs1pad_encrypt_sign_complete(req, err);

	return err;
}

static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	unsigned int dst_len;
	unsigned int pos;
	u8 *out_buf;

	if (err)
		goto done;

	err = -EINVAL;
	dst_len = req_ctx->child_req.dst_len;
	if (dst_len < ctx->key_size - 1)
		goto done;

	out_buf = req_ctx->out_buf;
	if (dst_len == ctx->key_size) {
		if (out_buf[0] != 0x00)
			/* Decrypted value had no leading 0 byte */
			goto done;

		dst_len--;
		out_buf++;
	}

	if (out_buf[0] != 0x02)
		goto done;

	for (pos = 1; pos < dst_len; pos++)
		if (out_buf[pos] == 0x00)
			break;
	if (pos < 9 || pos == dst_len)
		goto done;
	pos++;

	err = 0;

	if (req->dst_len < dst_len - pos)
		err = -EOVERFLOW;
	req->dst_len = dst_len - pos;

	if (!err)
		sg_copy_from_buffer(req->dst,
				sg_nents_for_len(req->dst, req->dst_len),
				out_buf + pos, req->dst_len);

done:
	kzfree(req_ctx->out_buf);

	return err;
}

static void pkcs1pad_decrypt_complete_cb(
		struct crypto_async_request *child_async_req, int err)
{
	struct akcipher_request *req = child_async_req->data;
	struct crypto_async_request async_req;

	if (err == -EINPROGRESS)
		return;

	async_req.data = req->base.data;
	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
	async_req.flags = child_async_req->flags;
	req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
}

static int pkcs1pad_decrypt(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	int err;

	if (!ctx->key_size || req->src_len != ctx->key_size)
		return -EINVAL;

	req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
	if (!req_ctx->out_buf)
		return -ENOMEM;

	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
			    ctx->key_size, NULL);

	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
			pkcs1pad_decrypt_complete_cb, req);

	/* Reuse input buffer, output to a new buffer */
	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
				   req_ctx->out_sg, req->src_len,
				   ctx->key_size);

	err = crypto_akcipher_decrypt(&req_ctx->child_req);
	if (err != -EINPROGRESS && err != -EBUSY)
		return pkcs1pad_decrypt_complete(req, err);

	return err;
}

static int pkcs1pad_sign(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
	const struct rsa_asn1_template *digest_info = ictx->digest_info;
	int err;
	unsigned int ps_end, digest_size = 0;

	if (!ctx->key_size)
		return -EINVAL;

	if (digest_info)
		digest_size = digest_info->size;

	if (req->src_len + digest_size > ctx->key_size - 11)
		return -EOVERFLOW;

	if (req->dst_len < ctx->key_size) {
		req->dst_len = ctx->key_size;
		return -EOVERFLOW;
	}

	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
				  GFP_KERNEL);
	if (!req_ctx->in_buf)
		return -ENOMEM;

	ps_end = ctx->key_size - digest_size - req->src_len - 2;
	req_ctx->in_buf[0] = 0x01;
	memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
	req_ctx->in_buf[ps_end] = 0x00;

	if (digest_info)
		memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
		       digest_info->size);

	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
			ctx->key_size - 1 - req->src_len, req->src);

	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
			pkcs1pad_encrypt_sign_complete_cb, req);

	/* Reuse output buffer */
	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
				   req->dst, ctx->key_size - 1, req->dst_len);

	err = crypto_akcipher_decrypt(&req_ctx->child_req);
	if (err != -EINPROGRESS && err != -EBUSY)
		return pkcs1pad_encrypt_sign_complete(req, err);

	return err;
}

static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
	const struct rsa_asn1_template *digest_info = ictx->digest_info;
	unsigned int dst_len;
	unsigned int pos;
	u8 *out_buf;

	if (err)
		goto done;

	err = -EINVAL;
	dst_len = req_ctx->child_req.dst_len;
	if (dst_len < ctx->key_size - 1)
		goto done;

	out_buf = req_ctx->out_buf;
	if (dst_len == ctx->key_size) {
		if (out_buf[0] != 0x00)
			/* Decrypted value had no leading 0 byte */
			goto done;

		dst_len--;
		out_buf++;
	}

	err = -EBADMSG;
	if (out_buf[0] != 0x01)
		goto done;

	for (pos = 1; pos < dst_len; pos++)
		if (out_buf[pos] != 0xff)
			break;

	if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
		goto done;
	pos++;

	if (digest_info) {
		if (crypto_memneq(out_buf + pos, digest_info->data,
				  digest_info->size))
			goto done;

		pos += digest_info->size;
	}

	err = 0;

	if (req->dst_len != dst_len - pos) {
		err = -EKEYREJECTED;
		req->dst_len = dst_len - pos;
		goto done;
	}
	/* Extract appended digest. */
	sg_pcopy_to_buffer(req->src,
			   sg_nents_for_len(req->src,
					    req->src_len + req->dst_len),
			   req_ctx->out_buf + ctx->key_size,
			   req->dst_len, ctx->key_size);
	/* Do the actual verification step. */
	if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
		   req->dst_len) != 0)
		err = -EKEYREJECTED;
done:
	kzfree(req_ctx->out_buf);

	return err;
}

static void pkcs1pad_verify_complete_cb(
		struct crypto_async_request *child_async_req, int err)
{
	struct akcipher_request *req = child_async_req->data;
	struct crypto_async_request async_req;

	if (err == -EINPROGRESS)
		return;

	async_req.data = req->base.data;
	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
	async_req.flags = child_async_req->flags;
	req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
}

/*
 * The verify operation is here for completeness similar to the verification
 * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
 * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
 * retrieve the DigestInfo from a signature, instead the user is expected
 * to call the sign operation to generate the expected signature and compare
 * signatures instead of the message-digests.
 */
static int pkcs1pad_verify(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
	int err;

	if (WARN_ON(req->dst) ||
	    WARN_ON(!req->dst_len) ||
	    !ctx->key_size || req->src_len < ctx->key_size)
		return -EINVAL;

	req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
	if (!req_ctx->out_buf)
		return -ENOMEM;

	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
			    ctx->key_size, NULL);

	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
			pkcs1pad_verify_complete_cb, req);

	/* Reuse input buffer, output to a new buffer */
	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
				   req_ctx->out_sg, req->src_len,
				   ctx->key_size);

	err = crypto_akcipher_encrypt(&req_ctx->child_req);
	if (err != -EINPROGRESS && err != -EBUSY)
		return pkcs1pad_verify_complete(req, err);

	return err;
}

static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
{
	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
	struct crypto_akcipher *child_tfm;

	child_tfm = crypto_spawn_akcipher(&ictx->spawn);
	if (IS_ERR(child_tfm))
		return PTR_ERR(child_tfm);

	ctx->child = child_tfm;
	return 0;
}

static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
{
	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);

	crypto_free_akcipher(ctx->child);
}

static void pkcs1pad_free(struct akcipher_instance *inst)
{
	struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
	struct crypto_akcipher_spawn *spawn = &ctx->spawn;

	crypto_drop_akcipher(spawn);
	kfree(inst);
}

static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	const struct rsa_asn1_template *digest_info;
	struct crypto_attr_type *algt;
	struct akcipher_instance *inst;
	struct pkcs1pad_inst_ctx *ctx;
	struct crypto_akcipher_spawn *spawn;
	struct akcipher_alg *rsa_alg;
	const char *rsa_alg_name;
	const char *hash_name;
	int err;

	algt = crypto_get_attr_type(tb);
	if (IS_ERR(algt))
		return PTR_ERR(algt);

	if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
		return -EINVAL;

	rsa_alg_name = crypto_attr_alg_name(tb[1]);
	if (IS_ERR(rsa_alg_name))
		return PTR_ERR(rsa_alg_name);

	hash_name = crypto_attr_alg_name(tb[2]);
	if (IS_ERR(hash_name))
		hash_name = NULL;

	if (hash_name) {
		digest_info = rsa_lookup_asn1(hash_name);
		if (!digest_info)
			return -EINVAL;
	} else
		digest_info = NULL;

	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;

	ctx = akcipher_instance_ctx(inst);
	spawn = &ctx->spawn;
	ctx->digest_info = digest_info;

	crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
	err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
			crypto_requires_sync(algt->type, algt->mask));
	if (err)
		goto out_free_inst;

	rsa_alg = crypto_spawn_akcipher_alg(spawn);

	err = -ENAMETOOLONG;

	if (!hash_name) {
		if (snprintf(inst->alg.base.cra_name,
			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
			     rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
			goto out_drop_alg;

		if (snprintf(inst->alg.base.cra_driver_name,
			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
			     rsa_alg->base.cra_driver_name) >=
			     CRYPTO_MAX_ALG_NAME)
			goto out_drop_alg;
	} else {
		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
			     "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
			     hash_name) >= CRYPTO_MAX_ALG_NAME)
			goto out_drop_alg;

		if (snprintf(inst->alg.base.cra_driver_name,
			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
			     rsa_alg->base.cra_driver_name,
			     hash_name) >= CRYPTO_MAX_ALG_NAME)
			goto out_drop_alg;
	}

	inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
	inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
	inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);

	inst->alg.init = pkcs1pad_init_tfm;
	inst->alg.exit = pkcs1pad_exit_tfm;

	inst->alg.encrypt = pkcs1pad_encrypt;
	inst->alg.decrypt = pkcs1pad_decrypt;
	inst->alg.sign = pkcs1pad_sign;
	inst->alg.verify = pkcs1pad_verify;
	inst->alg.set_pub_key = pkcs1pad_set_pub_key;
	inst->alg.set_priv_key = pkcs1pad_set_priv_key;
	inst->alg.max_size = pkcs1pad_get_max_size;
	inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;

	inst->free = pkcs1pad_free;

	err = akcipher_register_instance(tmpl, inst);
	if (err)
		goto out_drop_alg;

	return 0;

out_drop_alg:
	crypto_drop_akcipher(spawn);
out_free_inst:
	kfree(inst);
	return err;
}

struct crypto_template rsa_pkcs1pad_tmpl = {
	.name = "pkcs1pad",
	.create = pkcs1pad_create,
	.module = THIS_MODULE,
};