xref: /OK3568_Linux_fs/kernel/crypto/rsa-pkcs1pad.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * RSA padding templates.
4  *
5  * Copyright (c) 2015  Intel Corporation
6  */
7 
8 #include <crypto/algapi.h>
9 #include <crypto/akcipher.h>
10 #include <crypto/internal/akcipher.h>
11 #include <crypto/internal/rsa.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/random.h>
17 #include <linux/scatterlist.h>
18 
19 /*
20  * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
21  */
22 static const u8 rsa_digest_info_md5[] = {
23 	0x30, 0x20, 0x30, 0x0c, 0x06, 0x08,
24 	0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */
25 	0x05, 0x00, 0x04, 0x10
26 };
27 
28 static const u8 rsa_digest_info_sha1[] = {
29 	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
30 	0x2b, 0x0e, 0x03, 0x02, 0x1a,
31 	0x05, 0x00, 0x04, 0x14
32 };
33 
34 static const u8 rsa_digest_info_rmd160[] = {
35 	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
36 	0x2b, 0x24, 0x03, 0x02, 0x01,
37 	0x05, 0x00, 0x04, 0x14
38 };
39 
40 static const u8 rsa_digest_info_sha224[] = {
41 	0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
42 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
43 	0x05, 0x00, 0x04, 0x1c
44 };
45 
46 static const u8 rsa_digest_info_sha256[] = {
47 	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
48 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
49 	0x05, 0x00, 0x04, 0x20
50 };
51 
52 static const u8 rsa_digest_info_sha384[] = {
53 	0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
54 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
55 	0x05, 0x00, 0x04, 0x30
56 };
57 
58 static const u8 rsa_digest_info_sha512[] = {
59 	0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
60 	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
61 	0x05, 0x00, 0x04, 0x40
62 };
63 
64 static const struct rsa_asn1_template {
65 	const char	*name;
66 	const u8	*data;
67 	size_t		size;
68 } rsa_asn1_templates[] = {
69 #define _(X) { #X, rsa_digest_info_##X, sizeof(rsa_digest_info_##X) }
70 	_(md5),
71 	_(sha1),
72 	_(rmd160),
73 	_(sha256),
74 	_(sha384),
75 	_(sha512),
76 	_(sha224),
77 	{ NULL }
78 #undef _
79 };
80 
rsa_lookup_asn1(const char * name)81 static const struct rsa_asn1_template *rsa_lookup_asn1(const char *name)
82 {
83 	const struct rsa_asn1_template *p;
84 
85 	for (p = rsa_asn1_templates; p->name; p++)
86 		if (strcmp(name, p->name) == 0)
87 			return p;
88 	return NULL;
89 }
90 
91 struct pkcs1pad_ctx {
92 	struct crypto_akcipher *child;
93 	unsigned int key_size;
94 };
95 
96 struct pkcs1pad_inst_ctx {
97 	struct crypto_akcipher_spawn spawn;
98 	const struct rsa_asn1_template *digest_info;
99 };
100 
101 struct pkcs1pad_request {
102 	struct scatterlist in_sg[2], out_sg[1];
103 	uint8_t *in_buf, *out_buf;
104 	struct akcipher_request child_req;
105 };
106 
pkcs1pad_set_pub_key(struct crypto_akcipher * tfm,const void * key,unsigned int keylen)107 static int pkcs1pad_set_pub_key(struct crypto_akcipher *tfm, const void *key,
108 		unsigned int keylen)
109 {
110 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
111 	int err;
112 
113 	ctx->key_size = 0;
114 
115 	err = crypto_akcipher_set_pub_key(ctx->child, key, keylen);
116 	if (err)
117 		return err;
118 
119 	/* Find out new modulus size from rsa implementation */
120 	err = crypto_akcipher_maxsize(ctx->child);
121 	if (err > PAGE_SIZE)
122 		return -ENOTSUPP;
123 
124 	ctx->key_size = err;
125 	return 0;
126 }
127 
pkcs1pad_set_priv_key(struct crypto_akcipher * tfm,const void * key,unsigned int keylen)128 static int pkcs1pad_set_priv_key(struct crypto_akcipher *tfm, const void *key,
129 		unsigned int keylen)
130 {
131 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
132 	int err;
133 
134 	ctx->key_size = 0;
135 
136 	err = crypto_akcipher_set_priv_key(ctx->child, key, keylen);
137 	if (err)
138 		return err;
139 
140 	/* Find out new modulus size from rsa implementation */
141 	err = crypto_akcipher_maxsize(ctx->child);
142 	if (err > PAGE_SIZE)
143 		return -ENOTSUPP;
144 
145 	ctx->key_size = err;
146 	return 0;
147 }
148 
pkcs1pad_get_max_size(struct crypto_akcipher * tfm)149 static unsigned int pkcs1pad_get_max_size(struct crypto_akcipher *tfm)
150 {
151 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
152 
153 	/*
154 	 * The maximum destination buffer size for the encrypt/sign operations
155 	 * will be the same as for RSA, even though it's smaller for
156 	 * decrypt/verify.
157 	 */
158 
159 	return ctx->key_size;
160 }
161 
pkcs1pad_sg_set_buf(struct scatterlist * sg,void * buf,size_t len,struct scatterlist * next)162 static void pkcs1pad_sg_set_buf(struct scatterlist *sg, void *buf, size_t len,
163 		struct scatterlist *next)
164 {
165 	int nsegs = next ? 2 : 1;
166 
167 	sg_init_table(sg, nsegs);
168 	sg_set_buf(sg, buf, len);
169 
170 	if (next)
171 		sg_chain(sg, nsegs, next);
172 }
173 
pkcs1pad_encrypt_sign_complete(struct akcipher_request * req,int err)174 static int pkcs1pad_encrypt_sign_complete(struct akcipher_request *req, int err)
175 {
176 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
177 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
178 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
179 	unsigned int pad_len;
180 	unsigned int len;
181 	u8 *out_buf;
182 
183 	if (err)
184 		goto out;
185 
186 	len = req_ctx->child_req.dst_len;
187 	pad_len = ctx->key_size - len;
188 
189 	/* Four billion to one */
190 	if (likely(!pad_len))
191 		goto out;
192 
193 	out_buf = kzalloc(ctx->key_size, GFP_KERNEL);
194 	err = -ENOMEM;
195 	if (!out_buf)
196 		goto out;
197 
198 	sg_copy_to_buffer(req->dst, sg_nents_for_len(req->dst, len),
199 			  out_buf + pad_len, len);
200 	sg_copy_from_buffer(req->dst,
201 			    sg_nents_for_len(req->dst, ctx->key_size),
202 			    out_buf, ctx->key_size);
203 	kfree_sensitive(out_buf);
204 
205 out:
206 	req->dst_len = ctx->key_size;
207 
208 	kfree(req_ctx->in_buf);
209 
210 	return err;
211 }
212 
pkcs1pad_encrypt_sign_complete_cb(struct crypto_async_request * child_async_req,int err)213 static void pkcs1pad_encrypt_sign_complete_cb(
214 		struct crypto_async_request *child_async_req, int err)
215 {
216 	struct akcipher_request *req = child_async_req->data;
217 	struct crypto_async_request async_req;
218 
219 	if (err == -EINPROGRESS)
220 		return;
221 
222 	async_req.data = req->base.data;
223 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
224 	async_req.flags = child_async_req->flags;
225 	req->base.complete(&async_req,
226 			pkcs1pad_encrypt_sign_complete(req, err));
227 }
228 
pkcs1pad_encrypt(struct akcipher_request * req)229 static int pkcs1pad_encrypt(struct akcipher_request *req)
230 {
231 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
232 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
233 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
234 	int err;
235 	unsigned int i, ps_end;
236 
237 	if (!ctx->key_size)
238 		return -EINVAL;
239 
240 	if (req->src_len > ctx->key_size - 11)
241 		return -EOVERFLOW;
242 
243 	if (req->dst_len < ctx->key_size) {
244 		req->dst_len = ctx->key_size;
245 		return -EOVERFLOW;
246 	}
247 
248 	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
249 				  GFP_KERNEL);
250 	if (!req_ctx->in_buf)
251 		return -ENOMEM;
252 
253 	ps_end = ctx->key_size - req->src_len - 2;
254 	req_ctx->in_buf[0] = 0x02;
255 	for (i = 1; i < ps_end; i++)
256 		req_ctx->in_buf[i] = 1 + prandom_u32_max(255);
257 	req_ctx->in_buf[ps_end] = 0x00;
258 
259 	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
260 			ctx->key_size - 1 - req->src_len, req->src);
261 
262 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
263 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
264 			pkcs1pad_encrypt_sign_complete_cb, req);
265 
266 	/* Reuse output buffer */
267 	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
268 				   req->dst, ctx->key_size - 1, req->dst_len);
269 
270 	err = crypto_akcipher_encrypt(&req_ctx->child_req);
271 	if (err != -EINPROGRESS && err != -EBUSY)
272 		return pkcs1pad_encrypt_sign_complete(req, err);
273 
274 	return err;
275 }
276 
pkcs1pad_decrypt_complete(struct akcipher_request * req,int err)277 static int pkcs1pad_decrypt_complete(struct akcipher_request *req, int err)
278 {
279 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
280 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
281 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
282 	unsigned int dst_len;
283 	unsigned int pos;
284 	u8 *out_buf;
285 
286 	if (err)
287 		goto done;
288 
289 	err = -EINVAL;
290 	dst_len = req_ctx->child_req.dst_len;
291 	if (dst_len < ctx->key_size - 1)
292 		goto done;
293 
294 	out_buf = req_ctx->out_buf;
295 	if (dst_len == ctx->key_size) {
296 		if (out_buf[0] != 0x00)
297 			/* Decrypted value had no leading 0 byte */
298 			goto done;
299 
300 		dst_len--;
301 		out_buf++;
302 	}
303 
304 	if (out_buf[0] != 0x02)
305 		goto done;
306 
307 	for (pos = 1; pos < dst_len; pos++)
308 		if (out_buf[pos] == 0x00)
309 			break;
310 	if (pos < 9 || pos == dst_len)
311 		goto done;
312 	pos++;
313 
314 	err = 0;
315 
316 	if (req->dst_len < dst_len - pos)
317 		err = -EOVERFLOW;
318 	req->dst_len = dst_len - pos;
319 
320 	if (!err)
321 		sg_copy_from_buffer(req->dst,
322 				sg_nents_for_len(req->dst, req->dst_len),
323 				out_buf + pos, req->dst_len);
324 
325 done:
326 	kfree_sensitive(req_ctx->out_buf);
327 
328 	return err;
329 }
330 
pkcs1pad_decrypt_complete_cb(struct crypto_async_request * child_async_req,int err)331 static void pkcs1pad_decrypt_complete_cb(
332 		struct crypto_async_request *child_async_req, int err)
333 {
334 	struct akcipher_request *req = child_async_req->data;
335 	struct crypto_async_request async_req;
336 
337 	if (err == -EINPROGRESS)
338 		return;
339 
340 	async_req.data = req->base.data;
341 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
342 	async_req.flags = child_async_req->flags;
343 	req->base.complete(&async_req, pkcs1pad_decrypt_complete(req, err));
344 }
345 
pkcs1pad_decrypt(struct akcipher_request * req)346 static int pkcs1pad_decrypt(struct akcipher_request *req)
347 {
348 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
349 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
350 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
351 	int err;
352 
353 	if (!ctx->key_size || req->src_len != ctx->key_size)
354 		return -EINVAL;
355 
356 	req_ctx->out_buf = kmalloc(ctx->key_size, GFP_KERNEL);
357 	if (!req_ctx->out_buf)
358 		return -ENOMEM;
359 
360 	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
361 			    ctx->key_size, NULL);
362 
363 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
364 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
365 			pkcs1pad_decrypt_complete_cb, req);
366 
367 	/* Reuse input buffer, output to a new buffer */
368 	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
369 				   req_ctx->out_sg, req->src_len,
370 				   ctx->key_size);
371 
372 	err = crypto_akcipher_decrypt(&req_ctx->child_req);
373 	if (err != -EINPROGRESS && err != -EBUSY)
374 		return pkcs1pad_decrypt_complete(req, err);
375 
376 	return err;
377 }
378 
pkcs1pad_sign(struct akcipher_request * req)379 static int pkcs1pad_sign(struct akcipher_request *req)
380 {
381 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
382 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
383 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
384 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
385 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
386 	const struct rsa_asn1_template *digest_info = ictx->digest_info;
387 	int err;
388 	unsigned int ps_end, digest_size = 0;
389 
390 	if (!ctx->key_size)
391 		return -EINVAL;
392 
393 	if (digest_info)
394 		digest_size = digest_info->size;
395 
396 	if (req->src_len + digest_size > ctx->key_size - 11)
397 		return -EOVERFLOW;
398 
399 	if (req->dst_len < ctx->key_size) {
400 		req->dst_len = ctx->key_size;
401 		return -EOVERFLOW;
402 	}
403 
404 	req_ctx->in_buf = kmalloc(ctx->key_size - 1 - req->src_len,
405 				  GFP_KERNEL);
406 	if (!req_ctx->in_buf)
407 		return -ENOMEM;
408 
409 	ps_end = ctx->key_size - digest_size - req->src_len - 2;
410 	req_ctx->in_buf[0] = 0x01;
411 	memset(req_ctx->in_buf + 1, 0xff, ps_end - 1);
412 	req_ctx->in_buf[ps_end] = 0x00;
413 
414 	if (digest_info)
415 		memcpy(req_ctx->in_buf + ps_end + 1, digest_info->data,
416 		       digest_info->size);
417 
418 	pkcs1pad_sg_set_buf(req_ctx->in_sg, req_ctx->in_buf,
419 			ctx->key_size - 1 - req->src_len, req->src);
420 
421 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
422 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
423 			pkcs1pad_encrypt_sign_complete_cb, req);
424 
425 	/* Reuse output buffer */
426 	akcipher_request_set_crypt(&req_ctx->child_req, req_ctx->in_sg,
427 				   req->dst, ctx->key_size - 1, req->dst_len);
428 
429 	err = crypto_akcipher_decrypt(&req_ctx->child_req);
430 	if (err != -EINPROGRESS && err != -EBUSY)
431 		return pkcs1pad_encrypt_sign_complete(req, err);
432 
433 	return err;
434 }
435 
pkcs1pad_verify_complete(struct akcipher_request * req,int err)436 static int pkcs1pad_verify_complete(struct akcipher_request *req, int err)
437 {
438 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
439 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
440 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
441 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
442 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
443 	const struct rsa_asn1_template *digest_info = ictx->digest_info;
444 	unsigned int dst_len;
445 	unsigned int pos;
446 	u8 *out_buf;
447 
448 	if (err)
449 		goto done;
450 
451 	err = -EINVAL;
452 	dst_len = req_ctx->child_req.dst_len;
453 	if (dst_len < ctx->key_size - 1)
454 		goto done;
455 
456 	out_buf = req_ctx->out_buf;
457 	if (dst_len == ctx->key_size) {
458 		if (out_buf[0] != 0x00)
459 			/* Decrypted value had no leading 0 byte */
460 			goto done;
461 
462 		dst_len--;
463 		out_buf++;
464 	}
465 
466 	err = -EBADMSG;
467 	if (out_buf[0] != 0x01)
468 		goto done;
469 
470 	for (pos = 1; pos < dst_len; pos++)
471 		if (out_buf[pos] != 0xff)
472 			break;
473 
474 	if (pos < 9 || pos == dst_len || out_buf[pos] != 0x00)
475 		goto done;
476 	pos++;
477 
478 	if (digest_info) {
479 		if (digest_info->size > dst_len - pos)
480 			goto done;
481 		if (crypto_memneq(out_buf + pos, digest_info->data,
482 				  digest_info->size))
483 			goto done;
484 
485 		pos += digest_info->size;
486 	}
487 
488 	err = 0;
489 
490 	if (req->dst_len != dst_len - pos) {
491 		err = -EKEYREJECTED;
492 		req->dst_len = dst_len - pos;
493 		goto done;
494 	}
495 	/* Extract appended digest. */
496 	sg_pcopy_to_buffer(req->src,
497 			   sg_nents_for_len(req->src,
498 					    req->src_len + req->dst_len),
499 			   req_ctx->out_buf + ctx->key_size,
500 			   req->dst_len, req->src_len);
501 	/* Do the actual verification step. */
502 	if (memcmp(req_ctx->out_buf + ctx->key_size, out_buf + pos,
503 		   req->dst_len) != 0)
504 		err = -EKEYREJECTED;
505 done:
506 	kfree_sensitive(req_ctx->out_buf);
507 
508 	return err;
509 }
510 
pkcs1pad_verify_complete_cb(struct crypto_async_request * child_async_req,int err)511 static void pkcs1pad_verify_complete_cb(
512 		struct crypto_async_request *child_async_req, int err)
513 {
514 	struct akcipher_request *req = child_async_req->data;
515 	struct crypto_async_request async_req;
516 
517 	if (err == -EINPROGRESS)
518 		return;
519 
520 	async_req.data = req->base.data;
521 	async_req.tfm = crypto_akcipher_tfm(crypto_akcipher_reqtfm(req));
522 	async_req.flags = child_async_req->flags;
523 	req->base.complete(&async_req, pkcs1pad_verify_complete(req, err));
524 }
525 
526 /*
527  * The verify operation is here for completeness similar to the verification
528  * defined in RFC2313 section 10.2 except that block type 0 is not accepted,
529  * as in RFC2437.  RFC2437 section 9.2 doesn't define any operation to
530  * retrieve the DigestInfo from a signature, instead the user is expected
531  * to call the sign operation to generate the expected signature and compare
532  * signatures instead of the message-digests.
533  */
pkcs1pad_verify(struct akcipher_request * req)534 static int pkcs1pad_verify(struct akcipher_request *req)
535 {
536 	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
537 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
538 	struct pkcs1pad_request *req_ctx = akcipher_request_ctx(req);
539 	int err;
540 
541 	if (WARN_ON(req->dst) ||
542 	    WARN_ON(!req->dst_len) ||
543 	    !ctx->key_size || req->src_len != ctx->key_size)
544 		return -EINVAL;
545 
546 	req_ctx->out_buf = kmalloc(ctx->key_size + req->dst_len, GFP_KERNEL);
547 	if (!req_ctx->out_buf)
548 		return -ENOMEM;
549 
550 	pkcs1pad_sg_set_buf(req_ctx->out_sg, req_ctx->out_buf,
551 			    ctx->key_size, NULL);
552 
553 	akcipher_request_set_tfm(&req_ctx->child_req, ctx->child);
554 	akcipher_request_set_callback(&req_ctx->child_req, req->base.flags,
555 			pkcs1pad_verify_complete_cb, req);
556 
557 	/* Reuse input buffer, output to a new buffer */
558 	akcipher_request_set_crypt(&req_ctx->child_req, req->src,
559 				   req_ctx->out_sg, req->src_len,
560 				   ctx->key_size);
561 
562 	err = crypto_akcipher_encrypt(&req_ctx->child_req);
563 	if (err != -EINPROGRESS && err != -EBUSY)
564 		return pkcs1pad_verify_complete(req, err);
565 
566 	return err;
567 }
568 
pkcs1pad_init_tfm(struct crypto_akcipher * tfm)569 static int pkcs1pad_init_tfm(struct crypto_akcipher *tfm)
570 {
571 	struct akcipher_instance *inst = akcipher_alg_instance(tfm);
572 	struct pkcs1pad_inst_ctx *ictx = akcipher_instance_ctx(inst);
573 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
574 	struct crypto_akcipher *child_tfm;
575 
576 	child_tfm = crypto_spawn_akcipher(&ictx->spawn);
577 	if (IS_ERR(child_tfm))
578 		return PTR_ERR(child_tfm);
579 
580 	ctx->child = child_tfm;
581 	return 0;
582 }
583 
pkcs1pad_exit_tfm(struct crypto_akcipher * tfm)584 static void pkcs1pad_exit_tfm(struct crypto_akcipher *tfm)
585 {
586 	struct pkcs1pad_ctx *ctx = akcipher_tfm_ctx(tfm);
587 
588 	crypto_free_akcipher(ctx->child);
589 }
590 
pkcs1pad_free(struct akcipher_instance * inst)591 static void pkcs1pad_free(struct akcipher_instance *inst)
592 {
593 	struct pkcs1pad_inst_ctx *ctx = akcipher_instance_ctx(inst);
594 	struct crypto_akcipher_spawn *spawn = &ctx->spawn;
595 
596 	crypto_drop_akcipher(spawn);
597 	kfree(inst);
598 }
599 
pkcs1pad_create(struct crypto_template * tmpl,struct rtattr ** tb)600 static int pkcs1pad_create(struct crypto_template *tmpl, struct rtattr **tb)
601 {
602 	u32 mask;
603 	struct akcipher_instance *inst;
604 	struct pkcs1pad_inst_ctx *ctx;
605 	struct akcipher_alg *rsa_alg;
606 	const char *hash_name;
607 	int err;
608 
609 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AKCIPHER, &mask);
610 	if (err)
611 		return err;
612 
613 	inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
614 	if (!inst)
615 		return -ENOMEM;
616 
617 	ctx = akcipher_instance_ctx(inst);
618 
619 	err = crypto_grab_akcipher(&ctx->spawn, akcipher_crypto_instance(inst),
620 				   crypto_attr_alg_name(tb[1]), 0, mask);
621 	if (err)
622 		goto err_free_inst;
623 
624 	rsa_alg = crypto_spawn_akcipher_alg(&ctx->spawn);
625 
626 	if (strcmp(rsa_alg->base.cra_name, "rsa") != 0) {
627 		err = -EINVAL;
628 		goto err_free_inst;
629 	}
630 
631 	err = -ENAMETOOLONG;
632 	hash_name = crypto_attr_alg_name(tb[2]);
633 	if (IS_ERR(hash_name)) {
634 		if (snprintf(inst->alg.base.cra_name,
635 			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
636 			     rsa_alg->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
637 			goto err_free_inst;
638 
639 		if (snprintf(inst->alg.base.cra_driver_name,
640 			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s)",
641 			     rsa_alg->base.cra_driver_name) >=
642 			     CRYPTO_MAX_ALG_NAME)
643 			goto err_free_inst;
644 	} else {
645 		ctx->digest_info = rsa_lookup_asn1(hash_name);
646 		if (!ctx->digest_info) {
647 			err = -EINVAL;
648 			goto err_free_inst;
649 		}
650 
651 		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
652 			     "pkcs1pad(%s,%s)", rsa_alg->base.cra_name,
653 			     hash_name) >= CRYPTO_MAX_ALG_NAME)
654 			goto err_free_inst;
655 
656 		if (snprintf(inst->alg.base.cra_driver_name,
657 			     CRYPTO_MAX_ALG_NAME, "pkcs1pad(%s,%s)",
658 			     rsa_alg->base.cra_driver_name,
659 			     hash_name) >= CRYPTO_MAX_ALG_NAME)
660 			goto err_free_inst;
661 	}
662 
663 	inst->alg.base.cra_priority = rsa_alg->base.cra_priority;
664 	inst->alg.base.cra_ctxsize = sizeof(struct pkcs1pad_ctx);
665 
666 	inst->alg.init = pkcs1pad_init_tfm;
667 	inst->alg.exit = pkcs1pad_exit_tfm;
668 
669 	inst->alg.encrypt = pkcs1pad_encrypt;
670 	inst->alg.decrypt = pkcs1pad_decrypt;
671 	inst->alg.sign = pkcs1pad_sign;
672 	inst->alg.verify = pkcs1pad_verify;
673 	inst->alg.set_pub_key = pkcs1pad_set_pub_key;
674 	inst->alg.set_priv_key = pkcs1pad_set_priv_key;
675 	inst->alg.max_size = pkcs1pad_get_max_size;
676 	inst->alg.reqsize = sizeof(struct pkcs1pad_request) + rsa_alg->reqsize;
677 
678 	inst->free = pkcs1pad_free;
679 
680 	err = akcipher_register_instance(tmpl, inst);
681 	if (err) {
682 err_free_inst:
683 		pkcs1pad_free(inst);
684 	}
685 	return err;
686 }
687 
688 struct crypto_template rsa_pkcs1pad_tmpl = {
689 	.name = "pkcs1pad",
690 	.create = pkcs1pad_create,
691 	.module = THIS_MODULE,
692 };
693