xref: /openbmc/linux/crypto/rsa-pkcs1pad.c (revision 4da722ca)
1 /*
2  * RSA padding templates.
3  *
4  * Copyright (c) 2015  Intel Corporation
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  */
11 
12 #include <crypto/algapi.h>
13 #include <crypto/akcipher.h>
14 #include <crypto/internal/akcipher.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/random.h>
20 
21 /*
22  * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
23  */
24 static const u8 rsa_digest_info_md5[] = {
25 	0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
26 	0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
27 	0x05, 0x00, 0x04, 0x10
28 };
29 
30 static const u8 rsa_digest_info_sha1[] = {
31 	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
32 	0x2b, 0x0e, 0x03, 0x02, 0x1a,
33 	0x05, 0x00, 0x04, 0x14
34 };
35 
36 static const u8 rsa_digest_info_rmd160[] = {
37 	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
38 	0x2b, 0x24, 0x03, 0x02, 0x01,
39 	0x05, 0x00, 0x04, 0x14
40 };
41 
42 static const u8 rsa_digest_info_sha224[] = {
43 	0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
44 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
45 	0x05, 0x00, 0x04, 0x1c
46 };
47 
48 static const u8 rsa_digest_info_sha256[] = {
49 	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
50 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
51 	0x05, 0x00, 0x04, 0x20
52 };
53 
54 static const u8 rsa_digest_info_sha384[] = {
55 	0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
56 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
57 	0x05, 0x00, 0x04, 0x30
58 };
59 
60 static const u8 rsa_digest_info_sha512[] = {
61 	0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
62 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
63 	0x05, 0x00, 0x04, 0x40
64 };
65 
66 static const struct rsa_asn1_template {
67 	const char	*name;
68 	const u8	*data;
69 	size_t		size;
70 } rsa_asn1_templates[] = {
71 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
72 	_(md5),
73 	_(sha1),
74 	_(rmd160),
75 	_(sha256),
76 	_(sha384),
77 	_(sha512),
78 	_(sha224),
79 	{ NULL }
80 #undef _
81 };
82 
83 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
84 {
85 	const struct rsa_asn1_template *p;
86 
87 	for (p = rsa_asn1_templates; p->name; p++)
88 		if (strcmp(name, p->name) == 0)
89 			return p;
90 	return NULL;
91 }
92 
93 struct pkcs1pad_ctx {
94 	struct crypto_akcipher *child;
95 	unsigned int key_size;
96 };
97 
98 struct pkcs1pad_inst_ctx {
99 	struct crypto_akcipher_spawn spawn;
100 	const struct rsa_asn1_template *digest_info;
101 };
102 
103 struct pkcs1pad_request {
104 	struct scatterlist in_sg[2], out_sg[1];
105 	uint8_t *in_buf, *out_buf;
106 	struct akcipher_request child_req;
107 };
108 
109 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
110 		unsigned int keylen)
111 {
112 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
113 	int err;
114 
115 	ctx->key_size = 0;
116 
117 	err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
118 	if (err)
119 		return err;
120 
121 	/* Find out new modulus size from rsa implementation */
122 	err = crypto_akcipher_maxsize(ctx->child);
123 	if (err > PAGE_SIZE)
124 		return -ENOTSUPP;
125 
126 	ctx->key_size = err;
127 	return 0;
128 }
129 
130 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
131 		unsigned int keylen)
132 {
133 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
134 	int err;
135 
136 	ctx->key_size = 0;
137 
138 	err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
139 	if (err)
140 		return err;
141 
142 	/* Find out new modulus size from rsa implementation */
143 	err = crypto_akcipher_maxsize(ctx->child);
144 	if (err > PAGE_SIZE)
145 		return -ENOTSUPP;
146 
147 	ctx->key_size = err;
148 	return 0;
149 }
150 
151 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
152 {
153 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
154 
155 	/*
156 	 * The maximum destination buffer size for the encrypt/sign operations
157 	 * will be the same as for RSA, even though it's smaller for
158 	 * decrypt/verify.
159 	 */
160 
161 	return ctx->key_size;
162 }
163 
164 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
165 		struct scatterlist *next)
166 {
167 	int nsegs = next ? 2 : 1;
168 
169 	sg_init_table(sg, nsegs);
170 	sg_set_buf(sg, buf, len);
171 
172 	if (next)
173 		sg_chain(sg, nsegs, next);
174 }
175 
176 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
177 {
178 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
179 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
180 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
181 	unsigned int pad_len;
182 	unsigned int len;
183 	u8 *out_buf;
184 
185 	if (err)
186 		goto out;
187 
188 	len = req_ctx->child_req.dst_len;
189 	pad_len = ctx->key_size - len;
190 
191 	/* Four billion to one */
192 	if (likely(!pad_len))
193 		goto out;
194 
195 	out_buf = kzalloc(ctx->key_size, GFP_ATOMIC);
196 	err = -ENOMEM;
197 	if (!out_buf)
198 		goto out;
199 
200 	sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
201 			  out_buf + pad_len, len);
202 	sg_copy_from_buffer(req->dst,
203 			    sg_nents_for_len(req->dst, ctx->key_size),
204 			    out_buf, ctx->key_size);
205 	kzfree(out_buf);
206 
207 out:
208 	req->dst_len = ctx->key_size;
209 
210 	kfree(req_ctx->in_buf);
211 
212 	return err;
213 }
214 
215 static void pkcs1pad_encrypt_sign_complete_cb(
216 		struct crypto_async_request *child_async_req, int err)
217 {
218 	struct akcipher_request *req = child_async_req->data;
219 	struct crypto_async_request async_req;
220 
221 	if (err == -EINPROGRESS)
222 		return;
223 
224 	async_req.data = req->base.data;
225 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
226 	async_req.flags = child_async_req->flags;
227 	req->base.complete(&async_req,
228 			pkcs1pad_encrypt_sign_complete(req, err));
229 }
230 
231 static int pkcs1pad_encrypt(struct akcipher_request *req)
232 {
233 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
234 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
235 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
236 	int err;
237 	unsigned int i, ps_end;
238 
239 	if (!ctx->key_size)
240 		return -EINVAL;
241 
242 	if (req->src_len > ctx->key_size - 11)
243 		return -EOVERFLOW;
244 
245 	if (req->dst_len < ctx->key_size) {
246 		req->dst_len = ctx->key_size;
247 		return -EOVERFLOW;
248 	}
249 
250 	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
251 				  GFP_KERNEL);
252 	if (!req_ctx->in_buf)
253 		return -ENOMEM;
254 
255 	ps_end = ctx->key_size - req->src_len - 2;
256 	req_ctx->in_buf[0] = 0x02;
257 	for (i = 1; i < ps_end; i++)
258 		req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
259 	req_ctx->in_buf[ps_end] = 0x00;
260 
261 	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
262 			ctx->key_size - 1 - req->src_len, req->src);
263 
264 	req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
265 	if (!req_ctx->out_buf) {
266 		kfree(req_ctx->in_buf);
267 		return -ENOMEM;
268 	}
269 
270 	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
271 			ctx->key_size, NULL);
272 
273 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
274 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
275 			pkcs1pad_encrypt_sign_complete_cb, req);
276 
277 	/* Reuse output buffer */
278 	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
279 				   req->dst, ctx->key_size - 1, req->dst_len);
280 
281 	err = crypto_akcipher_encrypt(&req_ctx->child_req);
282 	if (err != -EINPROGRESS &&
283 			(err != -EBUSY ||
284 			 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
285 		return pkcs1pad_encrypt_sign_complete(req, err);
286 
287 	return err;
288 }
289 
290 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
291 {
292 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
293 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
294 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
295 	unsigned int dst_len;
296 	unsigned int pos;
297 	u8 *out_buf;
298 
299 	if (err)
300 		goto done;
301 
302 	err = -EINVAL;
303 	dst_len = req_ctx->child_req.dst_len;
304 	if (dst_len < ctx->key_size - 1)
305 		goto done;
306 
307 	out_buf = req_ctx->out_buf;
308 	if (dst_len == ctx->key_size) {
309 		if (out_buf[0] != 0x00)
310 			/* Decrypted value had no leading 0 byte */
311 			goto done;
312 
313 		dst_len--;
314 		out_buf++;
315 	}
316 
317 	if (out_buf[0] != 0x02)
318 		goto done;
319 
320 	for (pos = 1; pos < dst_len; pos++)
321 		if (out_buf[pos] == 0x00)
322 			break;
323 	if (pos < 9 || pos == dst_len)
324 		goto done;
325 	pos++;
326 
327 	err = 0;
328 
329 	if (req->dst_len < dst_len - pos)
330 		err = -EOVERFLOW;
331 	req->dst_len = dst_len - pos;
332 
333 	if (!err)
334 		sg_copy_from_buffer(req->dst,
335 				sg_nents_for_len(req->dst, req->dst_len),
336 				out_buf + pos, req->dst_len);
337 
338 done:
339 	kzfree(req_ctx->out_buf);
340 
341 	return err;
342 }
343 
344 static void pkcs1pad_decrypt_complete_cb(
345 		struct crypto_async_request *child_async_req, int err)
346 {
347 	struct akcipher_request *req = child_async_req->data;
348 	struct crypto_async_request async_req;
349 
350 	if (err == -EINPROGRESS)
351 		return;
352 
353 	async_req.data = req->base.data;
354 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
355 	async_req.flags = child_async_req->flags;
356 	req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
357 }
358 
359 static int pkcs1pad_decrypt(struct akcipher_request *req)
360 {
361 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
362 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
363 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
364 	int err;
365 
366 	if (!ctx->key_size || req->src_len != ctx->key_size)
367 		return -EINVAL;
368 
369 	req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
370 	if (!req_ctx->out_buf)
371 		return -ENOMEM;
372 
373 	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
374 			    ctx->key_size, NULL);
375 
376 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
377 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
378 			pkcs1pad_decrypt_complete_cb, req);
379 
380 	/* Reuse input buffer, output to a new buffer */
381 	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
382 				   req_ctx->out_sg, req->src_len,
383 				   ctx->key_size);
384 
385 	err = crypto_akcipher_decrypt(&req_ctx->child_req);
386 	if (err != -EINPROGRESS &&
387 			(err != -EBUSY ||
388 			 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
389 		return pkcs1pad_decrypt_complete(req, err);
390 
391 	return err;
392 }
393 
394 static int pkcs1pad_sign(struct akcipher_request *req)
395 {
396 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
397 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
398 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
399 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
400 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
401 	const struct rsa_asn1_template *digest_info = ictx->digest_info;
402 	int err;
403 	unsigned int ps_end, digest_size = 0;
404 
405 	if (!ctx->key_size)
406 		return -EINVAL;
407 
408 	digest_size = digest_info->size;
409 
410 	if (req->src_len + digest_size > ctx->key_size - 11)
411 		return -EOVERFLOW;
412 
413 	if (req->dst_len < ctx->key_size) {
414 		req->dst_len = ctx->key_size;
415 		return -EOVERFLOW;
416 	}
417 
418 	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
419 				  GFP_KERNEL);
420 	if (!req_ctx->in_buf)
421 		return -ENOMEM;
422 
423 	ps_end = ctx->key_size - digest_size - req->src_len - 2;
424 	req_ctx->in_buf[0] = 0x01;
425 	memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
426 	req_ctx->in_buf[ps_end] = 0x00;
427 
428 	memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
429 	       digest_info->size);
430 
431 	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
432 			ctx->key_size - 1 - req->src_len, req->src);
433 
434 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
435 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
436 			pkcs1pad_encrypt_sign_complete_cb, req);
437 
438 	/* Reuse output buffer */
439 	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
440 				   req->dst, ctx->key_size - 1, req->dst_len);
441 
442 	err = crypto_akcipher_sign(&req_ctx->child_req);
443 	if (err != -EINPROGRESS &&
444 			(err != -EBUSY ||
445 			 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
446 		return pkcs1pad_encrypt_sign_complete(req, err);
447 
448 	return err;
449 }
450 
451 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
452 {
453 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
454 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
455 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
456 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
457 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
458 	const struct rsa_asn1_template *digest_info = ictx->digest_info;
459 	unsigned int dst_len;
460 	unsigned int pos;
461 	u8 *out_buf;
462 
463 	if (err)
464 		goto done;
465 
466 	err = -EINVAL;
467 	dst_len = req_ctx->child_req.dst_len;
468 	if (dst_len < ctx->key_size - 1)
469 		goto done;
470 
471 	out_buf = req_ctx->out_buf;
472 	if (dst_len == ctx->key_size) {
473 		if (out_buf[0] != 0x00)
474 			/* Decrypted value had no leading 0 byte */
475 			goto done;
476 
477 		dst_len--;
478 		out_buf++;
479 	}
480 
481 	err = -EBADMSG;
482 	if (out_buf[0] != 0x01)
483 		goto done;
484 
485 	for (pos = 1; pos < dst_len; pos++)
486 		if (out_buf[pos] != 0xff)
487 			break;
488 
489 	if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
490 		goto done;
491 	pos++;
492 
493 	if (crypto_memneq(out_buf + pos, digest_info->data, digest_info->size))
494 		goto done;
495 
496 	pos += digest_info->size;
497 
498 	err = 0;
499 
500 	if (req->dst_len < dst_len - pos)
501 		err = -EOVERFLOW;
502 	req->dst_len = dst_len - pos;
503 
504 	if (!err)
505 		sg_copy_from_buffer(req->dst,
506 				sg_nents_for_len(req->dst, req->dst_len),
507 				out_buf + pos, req->dst_len);
508 done:
509 	kzfree(req_ctx->out_buf);
510 
511 	return err;
512 }
513 
514 static void pkcs1pad_verify_complete_cb(
515 		struct crypto_async_request *child_async_req, int err)
516 {
517 	struct akcipher_request *req = child_async_req->data;
518 	struct crypto_async_request async_req;
519 
520 	if (err == -EINPROGRESS)
521 		return;
522 
523 	async_req.data = req->base.data;
524 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
525 	async_req.flags = child_async_req->flags;
526 	req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
527 }
528 
529 /*
530  * The verify operation is here for completeness similar to the verification
531  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
532  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
533  * retrieve the DigestInfo from a signature, instead the user is expected
534  * to call the sign operation to generate the expected signature and compare
535  * signatures instead of the message-digests.
536  */
537 static int pkcs1pad_verify(struct akcipher_request *req)
538 {
539 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
540 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
541 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
542 	int err;
543 
544 	if (!ctx->key_size || req->src_len < ctx->key_size)
545 		return -EINVAL;
546 
547 	req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
548 	if (!req_ctx->out_buf)
549 		return -ENOMEM;
550 
551 	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
552 			    ctx->key_size, NULL);
553 
554 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
555 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
556 			pkcs1pad_verify_complete_cb, req);
557 
558 	/* Reuse input buffer, output to a new buffer */
559 	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
560 				   req_ctx->out_sg, req->src_len,
561 				   ctx->key_size);
562 
563 	err = crypto_akcipher_verify(&req_ctx->child_req);
564 	if (err != -EINPROGRESS &&
565 			(err != -EBUSY ||
566 			 !(req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)))
567 		return pkcs1pad_verify_complete(req, err);
568 
569 	return err;
570 }
571 
572 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
573 {
574 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
575 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
576 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
577 	struct crypto_akcipher *child_tfm;
578 
579 	child_tfm = crypto_spawn_akcipher(&ictx->spawn);
580 	if (IS_ERR(child_tfm))
581 		return PTR_ERR(child_tfm);
582 
583 	ctx->child = child_tfm;
584 	return 0;
585 }
586 
587 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
588 {
589 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
590 
591 	crypto_free_akcipher(ctx->child);
592 }
593 
594 static void pkcs1pad_free(struct akcipher_instance *inst)
595 {
596 	struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
597 	struct crypto_akcipher_spawn *spawn = &ctx->spawn;
598 
599 	crypto_drop_akcipher(spawn);
600 	kfree(inst);
601 }
602 
603 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
604 {
605 	const struct rsa_asn1_template *digest_info;
606 	struct crypto_attr_type *algt;
607 	struct akcipher_instance *inst;
608 	struct pkcs1pad_inst_ctx *ctx;
609 	struct crypto_akcipher_spawn *spawn;
610 	struct akcipher_alg *rsa_alg;
611 	const char *rsa_alg_name;
612 	const char *hash_name;
613 	int err;
614 
615 	algt = crypto_get_attr_type(tb);
616 	if (IS_ERR(algt))
617 		return PTR_ERR(algt);
618 
619 	if ((algt->type ^ CRYPTO_ALG_TYPE_AKCIPHER) & algt->mask)
620 		return -EINVAL;
621 
622 	rsa_alg_name = crypto_attr_alg_name(tb[1]);
623 	if (IS_ERR(rsa_alg_name))
624 		return PTR_ERR(rsa_alg_name);
625 
626 	hash_name = crypto_attr_alg_name(tb[2]);
627 	if (IS_ERR(hash_name))
628 		return PTR_ERR(hash_name);
629 
630 	digest_info = rsa_lookup_asn1(hash_name);
631 	if (!digest_info)
632 		return -EINVAL;
633 
634 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
635 	if (!inst)
636 		return -ENOMEM;
637 
638 	ctx = akcipher_instance_ctx(inst);
639 	spawn = &ctx->spawn;
640 	ctx->digest_info = digest_info;
641 
642 	crypto_set_spawn(&spawn->base, akcipher_crypto_instance(inst));
643 	err = crypto_grab_akcipher(spawn, rsa_alg_name, 0,
644 			crypto_requires_sync(algt->type, algt->mask));
645 	if (err)
646 		goto out_free_inst;
647 
648 	rsa_alg = crypto_spawn_akcipher_alg(spawn);
649 
650 	err = -ENAMETOOLONG;
651 
652 	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
653 		     "pkcs1pad(%s,%s)", rsa_alg->base.cra_name, hash_name) >=
654 	    CRYPTO_MAX_ALG_NAME ||
655 	    snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
656 		     "pkcs1pad(%s,%s)",
657 		     rsa_alg->base.cra_driver_name, hash_name) >=
658 	    CRYPTO_MAX_ALG_NAME)
659 		goto out_drop_alg;
660 
661 	inst->alg.base.cra_flags = rsa_alg->base.cra_flags & CRYPTO_ALG_ASYNC;
662 	inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
663 	inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
664 
665 	inst->alg.init = pkcs1pad_init_tfm;
666 	inst->alg.exit = pkcs1pad_exit_tfm;
667 
668 	inst->alg.encrypt = pkcs1pad_encrypt;
669 	inst->alg.decrypt = pkcs1pad_decrypt;
670 	inst->alg.sign = pkcs1pad_sign;
671 	inst->alg.verify = pkcs1pad_verify;
672 	inst->alg.set_pub_key = pkcs1pad_set_pub_key;
673 	inst->alg.set_priv_key = pkcs1pad_set_priv_key;
674 	inst->alg.max_size = pkcs1pad_get_max_size;
675 	inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
676 
677 	inst->free = pkcs1pad_free;
678 
679 	err = akcipher_register_instance(tmpl, inst);
680 	if (err)
681 		goto out_drop_alg;
682 
683 	return 0;
684 
685 out_drop_alg:
686 	crypto_drop_akcipher(spawn);
687 out_free_inst:
688 	kfree(inst);
689 	return err;
690 }
691 
692 struct crypto_template rsa_pkcs1pad_tmpl = {
693 	.name = "pkcs1pad",
694 	.create = pkcs1pad_create,
695 	.module = THIS_MODULE,
696 };
697