xref: /linux/crypto/skcipher.c (revision 0ae452440cb9fee9079dc925f40cd824c1a9de2a)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Symmetric key cipher operations.
4  *
5  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
6  * multiple page boundaries by using temporary blocks.  In user context,
7  * the kernel is given a chance to schedule us once per page.
8  *
9  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
10  */
11 
12 #include <crypto/internal/aead.h>
13 #include <crypto/internal/cipher.h>
14 #include <crypto/internal/skcipher.h>
15 #include <crypto/scatterwalk.h>
16 #include <linux/bug.h>
17 #include <linux/cryptouser.h>
18 #include <linux/err.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/seq_file.h>
22 #include <linux/slab.h>
23 #include <linux/string.h>
24 #include <linux/string_choices.h>
25 #include <net/netlink.h>
26 #include "skcipher.h"
27 
28 #define CRYPTO_ALG_TYPE_SKCIPHER_MASK	0x0000000e
29 
30 static const struct crypto_type crypto_skcipher_type;
31 
__crypto_skcipher_alg(struct crypto_alg * alg)32 static inline struct skcipher_alg *__crypto_skcipher_alg(
33 	struct crypto_alg *alg)
34 {
35 	return container_of(alg, struct skcipher_alg, base);
36 }
37 
skcipher_walk_virt(struct skcipher_walk * __restrict walk,struct skcipher_request * __restrict req,bool atomic)38 int skcipher_walk_virt(struct skcipher_walk *__restrict walk,
39 		       struct skcipher_request *__restrict req, bool atomic)
40 {
41 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
42 	struct skcipher_alg *alg;
43 
44 	might_sleep_if(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP);
45 
46 	alg = crypto_skcipher_alg(tfm);
47 
48 	walk->total = req->cryptlen;
49 	walk->nbytes = 0;
50 	walk->iv = req->iv;
51 	walk->oiv = req->iv;
52 	if (!(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP))
53 		atomic = true;
54 
55 	if (unlikely(!walk->total))
56 		return 0;
57 
58 	scatterwalk_start(&walk->in, req->src);
59 	scatterwalk_start(&walk->out, req->dst);
60 
61 	walk->blocksize = crypto_skcipher_blocksize(tfm);
62 	walk->ivsize = crypto_skcipher_ivsize(tfm);
63 	walk->alignmask = crypto_skcipher_alignmask(tfm);
64 
65 	if (alg->co.base.cra_type != &crypto_skcipher_type)
66 		walk->stride = alg->co.chunksize;
67 	else
68 		walk->stride = alg->walksize;
69 
70 	return skcipher_walk_first(walk, atomic);
71 }
72 EXPORT_SYMBOL_GPL(skcipher_walk_virt);
73 
skcipher_walk_aead_common(struct skcipher_walk * __restrict walk,struct aead_request * __restrict req,bool atomic)74 static int skcipher_walk_aead_common(struct skcipher_walk *__restrict walk,
75 				     struct aead_request *__restrict req,
76 				     bool atomic)
77 {
78 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
79 
80 	walk->nbytes = 0;
81 	walk->iv = req->iv;
82 	walk->oiv = req->iv;
83 	if (!(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP))
84 		atomic = true;
85 
86 	if (unlikely(!walk->total))
87 		return 0;
88 
89 	scatterwalk_start_at_pos(&walk->in, req->src, req->assoclen);
90 	scatterwalk_start_at_pos(&walk->out, req->dst, req->assoclen);
91 
92 	walk->blocksize = crypto_aead_blocksize(tfm);
93 	walk->stride = crypto_aead_chunksize(tfm);
94 	walk->ivsize = crypto_aead_ivsize(tfm);
95 	walk->alignmask = crypto_aead_alignmask(tfm);
96 
97 	return skcipher_walk_first(walk, atomic);
98 }
99 
skcipher_walk_aead_encrypt(struct skcipher_walk * __restrict walk,struct aead_request * __restrict req,bool atomic)100 int skcipher_walk_aead_encrypt(struct skcipher_walk *__restrict walk,
101 			       struct aead_request *__restrict req,
102 			       bool atomic)
103 {
104 	walk->total = req->cryptlen;
105 
106 	return skcipher_walk_aead_common(walk, req, atomic);
107 }
108 EXPORT_SYMBOL_GPL(skcipher_walk_aead_encrypt);
109 
skcipher_walk_aead_decrypt(struct skcipher_walk * __restrict walk,struct aead_request * __restrict req,bool atomic)110 int skcipher_walk_aead_decrypt(struct skcipher_walk *__restrict walk,
111 			       struct aead_request *__restrict req,
112 			       bool atomic)
113 {
114 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
115 
116 	walk->total = req->cryptlen - crypto_aead_authsize(tfm);
117 
118 	return skcipher_walk_aead_common(walk, req, atomic);
119 }
120 EXPORT_SYMBOL_GPL(skcipher_walk_aead_decrypt);
121 
skcipher_set_needkey(struct crypto_skcipher * tfm)122 static void skcipher_set_needkey(struct crypto_skcipher *tfm)
123 {
124 	if (crypto_skcipher_max_keysize(tfm) != 0)
125 		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
126 }
127 
skcipher_setkey_unaligned(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)128 static int skcipher_setkey_unaligned(struct crypto_skcipher *tfm,
129 				     const u8 *key, unsigned int keylen)
130 {
131 	unsigned long alignmask = crypto_skcipher_alignmask(tfm);
132 	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
133 	u8 *buffer, *alignbuffer;
134 	unsigned long absize;
135 	int ret;
136 
137 	absize = keylen + alignmask;
138 	buffer = kmalloc(absize, GFP_ATOMIC);
139 	if (!buffer)
140 		return -ENOMEM;
141 
142 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
143 	memcpy(alignbuffer, key, keylen);
144 	ret = cipher->setkey(tfm, alignbuffer, keylen);
145 	kfree_sensitive(buffer);
146 	return ret;
147 }
148 
crypto_skcipher_setkey(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)149 int crypto_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
150 			   unsigned int keylen)
151 {
152 	struct skcipher_alg *cipher = crypto_skcipher_alg(tfm);
153 	unsigned long alignmask = crypto_skcipher_alignmask(tfm);
154 	int err;
155 
156 	if (cipher->co.base.cra_type != &crypto_skcipher_type) {
157 		struct crypto_lskcipher **ctx = crypto_skcipher_ctx(tfm);
158 
159 		crypto_lskcipher_clear_flags(*ctx, CRYPTO_TFM_REQ_MASK);
160 		crypto_lskcipher_set_flags(*ctx,
161 					   crypto_skcipher_get_flags(tfm) &
162 					   CRYPTO_TFM_REQ_MASK);
163 		err = crypto_lskcipher_setkey(*ctx, key, keylen);
164 		goto out;
165 	}
166 
167 	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize)
168 		return -EINVAL;
169 
170 	if ((unsigned long)key & alignmask)
171 		err = skcipher_setkey_unaligned(tfm, key, keylen);
172 	else
173 		err = cipher->setkey(tfm, key, keylen);
174 
175 out:
176 	if (unlikely(err)) {
177 		skcipher_set_needkey(tfm);
178 		return err;
179 	}
180 
181 	crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
182 	return 0;
183 }
184 EXPORT_SYMBOL_GPL(crypto_skcipher_setkey);
185 
crypto_skcipher_encrypt(struct skcipher_request * req)186 int crypto_skcipher_encrypt(struct skcipher_request *req)
187 {
188 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
189 	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
190 
191 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
192 		return -ENOKEY;
193 	if (alg->co.base.cra_type != &crypto_skcipher_type)
194 		return crypto_lskcipher_encrypt_sg(req);
195 	return alg->encrypt(req);
196 }
197 EXPORT_SYMBOL_GPL(crypto_skcipher_encrypt);
198 
crypto_skcipher_decrypt(struct skcipher_request * req)199 int crypto_skcipher_decrypt(struct skcipher_request *req)
200 {
201 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
202 	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
203 
204 	if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
205 		return -ENOKEY;
206 	if (alg->co.base.cra_type != &crypto_skcipher_type)
207 		return crypto_lskcipher_decrypt_sg(req);
208 	return alg->decrypt(req);
209 }
210 EXPORT_SYMBOL_GPL(crypto_skcipher_decrypt);
211 
crypto_lskcipher_export(struct skcipher_request * req,void * out)212 static int crypto_lskcipher_export(struct skcipher_request *req, void *out)
213 {
214 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
215 	u8 *ivs = skcipher_request_ctx(req);
216 
217 	ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1);
218 
219 	memcpy(out, ivs + crypto_skcipher_ivsize(tfm),
220 	       crypto_skcipher_statesize(tfm));
221 
222 	return 0;
223 }
224 
crypto_lskcipher_import(struct skcipher_request * req,const void * in)225 static int crypto_lskcipher_import(struct skcipher_request *req, const void *in)
226 {
227 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
228 	u8 *ivs = skcipher_request_ctx(req);
229 
230 	ivs = PTR_ALIGN(ivs, crypto_skcipher_alignmask(tfm) + 1);
231 
232 	memcpy(ivs + crypto_skcipher_ivsize(tfm), in,
233 	       crypto_skcipher_statesize(tfm));
234 
235 	return 0;
236 }
237 
skcipher_noexport(struct skcipher_request * req,void * out)238 static int skcipher_noexport(struct skcipher_request *req, void *out)
239 {
240 	return 0;
241 }
242 
skcipher_noimport(struct skcipher_request * req,const void * in)243 static int skcipher_noimport(struct skcipher_request *req, const void *in)
244 {
245 	return 0;
246 }
247 
crypto_skcipher_export(struct skcipher_request * req,void * out)248 int crypto_skcipher_export(struct skcipher_request *req, void *out)
249 {
250 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
251 	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
252 
253 	if (alg->co.base.cra_type != &crypto_skcipher_type)
254 		return crypto_lskcipher_export(req, out);
255 	return alg->export(req, out);
256 }
257 EXPORT_SYMBOL_GPL(crypto_skcipher_export);
258 
crypto_skcipher_import(struct skcipher_request * req,const void * in)259 int crypto_skcipher_import(struct skcipher_request *req, const void *in)
260 {
261 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
262 	struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
263 
264 	if (alg->co.base.cra_type != &crypto_skcipher_type)
265 		return crypto_lskcipher_import(req, in);
266 	return alg->import(req, in);
267 }
268 EXPORT_SYMBOL_GPL(crypto_skcipher_import);
269 
crypto_skcipher_exit_tfm(struct crypto_tfm * tfm)270 static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
271 {
272 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
273 	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
274 
275 	alg->exit(skcipher);
276 }
277 
crypto_skcipher_init_tfm(struct crypto_tfm * tfm)278 static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
279 {
280 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
281 	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
282 
283 	skcipher_set_needkey(skcipher);
284 
285 	if (tfm->__crt_alg->cra_type != &crypto_skcipher_type) {
286 		unsigned am = crypto_skcipher_alignmask(skcipher);
287 		unsigned reqsize;
288 
289 		reqsize = am & ~(crypto_tfm_ctx_alignment() - 1);
290 		reqsize += crypto_skcipher_ivsize(skcipher);
291 		reqsize += crypto_skcipher_statesize(skcipher);
292 		crypto_skcipher_set_reqsize(skcipher, reqsize);
293 
294 		return crypto_init_lskcipher_ops_sg(tfm);
295 	}
296 
297 	crypto_skcipher_set_reqsize(skcipher, crypto_tfm_alg_reqsize(tfm));
298 
299 	if (alg->exit)
300 		skcipher->base.exit = crypto_skcipher_exit_tfm;
301 
302 	if (alg->init)
303 		return alg->init(skcipher);
304 
305 	return 0;
306 }
307 
crypto_skcipher_extsize(struct crypto_alg * alg)308 static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
309 {
310 	if (alg->cra_type != &crypto_skcipher_type)
311 		return sizeof(struct crypto_lskcipher *);
312 
313 	return crypto_alg_extsize(alg);
314 }
315 
crypto_skcipher_free_instance(struct crypto_instance * inst)316 static void crypto_skcipher_free_instance(struct crypto_instance *inst)
317 {
318 	struct skcipher_instance *skcipher =
319 		container_of(inst, struct skcipher_instance, s.base);
320 
321 	skcipher->free(skcipher);
322 }
323 
324 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
325 	__maybe_unused;
crypto_skcipher_show(struct seq_file * m,struct crypto_alg * alg)326 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
327 {
328 	struct skcipher_alg *skcipher = __crypto_skcipher_alg(alg);
329 
330 	seq_printf(m, "type         : skcipher\n");
331 	seq_printf(m, "async        : %s\n",
332 		   str_yes_no(alg->cra_flags & CRYPTO_ALG_ASYNC));
333 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
334 	seq_printf(m, "min keysize  : %u\n", skcipher->min_keysize);
335 	seq_printf(m, "max keysize  : %u\n", skcipher->max_keysize);
336 	seq_printf(m, "ivsize       : %u\n", skcipher->ivsize);
337 	seq_printf(m, "chunksize    : %u\n", skcipher->chunksize);
338 	seq_printf(m, "walksize     : %u\n", skcipher->walksize);
339 	seq_printf(m, "statesize    : %u\n", skcipher->statesize);
340 }
341 
crypto_skcipher_report(struct sk_buff * skb,struct crypto_alg * alg)342 static int __maybe_unused crypto_skcipher_report(
343 	struct sk_buff *skb, struct crypto_alg *alg)
344 {
345 	struct skcipher_alg *skcipher = __crypto_skcipher_alg(alg);
346 	struct crypto_report_blkcipher rblkcipher;
347 
348 	memset(&rblkcipher, 0, sizeof(rblkcipher));
349 
350 	strscpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
351 	strscpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
352 
353 	rblkcipher.blocksize = alg->cra_blocksize;
354 	rblkcipher.min_keysize = skcipher->min_keysize;
355 	rblkcipher.max_keysize = skcipher->max_keysize;
356 	rblkcipher.ivsize = skcipher->ivsize;
357 
358 	return nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
359 		       sizeof(rblkcipher), &rblkcipher);
360 }
361 
362 static const struct crypto_type crypto_skcipher_type = {
363 	.extsize = crypto_skcipher_extsize,
364 	.init_tfm = crypto_skcipher_init_tfm,
365 	.free = crypto_skcipher_free_instance,
366 #ifdef CONFIG_PROC_FS
367 	.show = crypto_skcipher_show,
368 #endif
369 #if IS_ENABLED(CONFIG_CRYPTO_USER)
370 	.report = crypto_skcipher_report,
371 #endif
372 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
373 	.maskset = CRYPTO_ALG_TYPE_SKCIPHER_MASK,
374 	.type = CRYPTO_ALG_TYPE_SKCIPHER,
375 	.tfmsize = offsetof(struct crypto_skcipher, base),
376 	.algsize = offsetof(struct skcipher_alg, base),
377 };
378 
crypto_grab_skcipher(struct crypto_skcipher_spawn * spawn,struct crypto_instance * inst,const char * name,u32 type,u32 mask)379 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,
380 			 struct crypto_instance *inst,
381 			 const char *name, u32 type, u32 mask)
382 {
383 	spawn->base.frontend = &crypto_skcipher_type;
384 	return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
385 }
386 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
387 
crypto_alloc_skcipher(const char * alg_name,u32 type,u32 mask)388 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
389 					      u32 type, u32 mask)
390 {
391 	return crypto_alloc_tfm(alg_name, &crypto_skcipher_type, type, mask);
392 }
393 EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);
394 
crypto_alloc_sync_skcipher(const char * alg_name,u32 type,u32 mask)395 struct crypto_sync_skcipher *crypto_alloc_sync_skcipher(
396 				const char *alg_name, u32 type, u32 mask)
397 {
398 	struct crypto_skcipher *tfm;
399 
400 	/* Only sync algorithms allowed. */
401 	mask |= CRYPTO_ALG_ASYNC | CRYPTO_ALG_SKCIPHER_REQSIZE_LARGE;
402 	type &= ~(CRYPTO_ALG_ASYNC | CRYPTO_ALG_SKCIPHER_REQSIZE_LARGE);
403 
404 	tfm = crypto_alloc_tfm(alg_name, &crypto_skcipher_type, type, mask);
405 
406 	/*
407 	 * Make sure we do not allocate something that might get used with
408 	 * an on-stack request: check the request size.
409 	 */
410 	if (!IS_ERR(tfm) && WARN_ON(crypto_skcipher_reqsize(tfm) >
411 				    MAX_SYNC_SKCIPHER_REQSIZE)) {
412 		crypto_free_skcipher(tfm);
413 		return ERR_PTR(-EINVAL);
414 	}
415 
416 	return (struct crypto_sync_skcipher *)tfm;
417 }
418 EXPORT_SYMBOL_GPL(crypto_alloc_sync_skcipher);
419 
crypto_has_skcipher(const char * alg_name,u32 type,u32 mask)420 int crypto_has_skcipher(const char *alg_name, u32 type, u32 mask)
421 {
422 	return crypto_type_has_alg(alg_name, &crypto_skcipher_type, type, mask);
423 }
424 EXPORT_SYMBOL_GPL(crypto_has_skcipher);
425 
skcipher_prepare_alg_common(struct skcipher_alg_common * alg)426 int skcipher_prepare_alg_common(struct skcipher_alg_common *alg)
427 {
428 	struct crypto_alg *base = &alg->base;
429 
430 	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8 ||
431 	    alg->statesize > PAGE_SIZE / 2 ||
432 	    (alg->ivsize + alg->statesize) > PAGE_SIZE / 2)
433 		return -EINVAL;
434 
435 	if (!alg->chunksize)
436 		alg->chunksize = base->cra_blocksize;
437 
438 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
439 
440 	return 0;
441 }
442 
skcipher_prepare_alg(struct skcipher_alg * alg)443 static int skcipher_prepare_alg(struct skcipher_alg *alg)
444 {
445 	struct crypto_alg *base = &alg->base;
446 	int err;
447 
448 	err = skcipher_prepare_alg_common(&alg->co);
449 	if (err)
450 		return err;
451 
452 	if (alg->walksize > PAGE_SIZE / 8)
453 		return -EINVAL;
454 
455 	if (!alg->walksize)
456 		alg->walksize = alg->chunksize;
457 
458 	if (!alg->statesize) {
459 		alg->import = skcipher_noimport;
460 		alg->export = skcipher_noexport;
461 	} else if (!(alg->import && alg->export))
462 		return -EINVAL;
463 
464 	base->cra_type = &crypto_skcipher_type;
465 	base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
466 
467 	return 0;
468 }
469 
crypto_register_skcipher(struct skcipher_alg * alg)470 int crypto_register_skcipher(struct skcipher_alg *alg)
471 {
472 	struct crypto_alg *base = &alg->base;
473 	int err;
474 
475 	err = skcipher_prepare_alg(alg);
476 	if (err)
477 		return err;
478 
479 	return crypto_register_alg(base);
480 }
481 EXPORT_SYMBOL_GPL(crypto_register_skcipher);
482 
crypto_unregister_skcipher(struct skcipher_alg * alg)483 void crypto_unregister_skcipher(struct skcipher_alg *alg)
484 {
485 	crypto_unregister_alg(&alg->base);
486 }
487 EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
488 
crypto_register_skciphers(struct skcipher_alg * algs,int count)489 int crypto_register_skciphers(struct skcipher_alg *algs, int count)
490 {
491 	int i, ret;
492 
493 	for (i = 0; i < count; i++) {
494 		ret = crypto_register_skcipher(&algs[i]);
495 		if (ret)
496 			goto err;
497 	}
498 
499 	return 0;
500 
501 err:
502 	for (--i; i >= 0; --i)
503 		crypto_unregister_skcipher(&algs[i]);
504 
505 	return ret;
506 }
507 EXPORT_SYMBOL_GPL(crypto_register_skciphers);
508 
crypto_unregister_skciphers(struct skcipher_alg * algs,int count)509 void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
510 {
511 	int i;
512 
513 	for (i = count - 1; i >= 0; --i)
514 		crypto_unregister_skcipher(&algs[i]);
515 }
516 EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
517 
skcipher_register_instance(struct crypto_template * tmpl,struct skcipher_instance * inst)518 int skcipher_register_instance(struct crypto_template *tmpl,
519 			   struct skcipher_instance *inst)
520 {
521 	int err;
522 
523 	if (WARN_ON(!inst->free))
524 		return -EINVAL;
525 
526 	err = skcipher_prepare_alg(&inst->alg);
527 	if (err)
528 		return err;
529 
530 	return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
531 }
532 EXPORT_SYMBOL_GPL(skcipher_register_instance);
533 
skcipher_setkey_simple(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)534 static int skcipher_setkey_simple(struct crypto_skcipher *tfm, const u8 *key,
535 				  unsigned int keylen)
536 {
537 	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
538 
539 	crypto_cipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK);
540 	crypto_cipher_set_flags(cipher, crypto_skcipher_get_flags(tfm) &
541 				CRYPTO_TFM_REQ_MASK);
542 	return crypto_cipher_setkey(cipher, key, keylen);
543 }
544 
skcipher_init_tfm_simple(struct crypto_skcipher * tfm)545 static int skcipher_init_tfm_simple(struct crypto_skcipher *tfm)
546 {
547 	struct skcipher_instance *inst = skcipher_alg_instance(tfm);
548 	struct crypto_cipher_spawn *spawn = skcipher_instance_ctx(inst);
549 	struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
550 	struct crypto_cipher *cipher;
551 
552 	cipher = crypto_spawn_cipher(spawn);
553 	if (IS_ERR(cipher))
554 		return PTR_ERR(cipher);
555 
556 	ctx->cipher = cipher;
557 	return 0;
558 }
559 
skcipher_exit_tfm_simple(struct crypto_skcipher * tfm)560 static void skcipher_exit_tfm_simple(struct crypto_skcipher *tfm)
561 {
562 	struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm);
563 
564 	crypto_free_cipher(ctx->cipher);
565 }
566 
skcipher_free_instance_simple(struct skcipher_instance * inst)567 static void skcipher_free_instance_simple(struct skcipher_instance *inst)
568 {
569 	crypto_drop_cipher(skcipher_instance_ctx(inst));
570 	kfree(inst);
571 }
572 
573 /**
574  * skcipher_alloc_instance_simple - allocate instance of simple block cipher mode
575  *
576  * Allocate an skcipher_instance for a simple block cipher mode of operation,
577  * e.g. cbc or ecb.  The instance context will have just a single crypto_spawn,
578  * that for the underlying cipher.  The {min,max}_keysize, ivsize, blocksize,
579  * alignmask, and priority are set from the underlying cipher but can be
580  * overridden if needed.  The tfm context defaults to skcipher_ctx_simple, and
581  * default ->setkey(), ->init(), and ->exit() methods are installed.
582  *
583  * @tmpl: the template being instantiated
584  * @tb: the template parameters
585  *
586  * Return: a pointer to the new instance, or an ERR_PTR().  The caller still
587  *	   needs to register the instance.
588  */
skcipher_alloc_instance_simple(struct crypto_template * tmpl,struct rtattr ** tb)589 struct skcipher_instance *skcipher_alloc_instance_simple(
590 	struct crypto_template *tmpl, struct rtattr **tb)
591 {
592 	u32 mask;
593 	struct skcipher_instance *inst;
594 	struct crypto_cipher_spawn *spawn;
595 	struct crypto_alg *cipher_alg;
596 	int err;
597 
598 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
599 	if (err)
600 		return ERR_PTR(err);
601 
602 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
603 	if (!inst)
604 		return ERR_PTR(-ENOMEM);
605 	spawn = skcipher_instance_ctx(inst);
606 
607 	err = crypto_grab_cipher(spawn, skcipher_crypto_instance(inst),
608 				 crypto_attr_alg_name(tb[1]), 0, mask);
609 	if (err)
610 		goto err_free_inst;
611 	cipher_alg = crypto_spawn_cipher_alg(spawn);
612 
613 	err = crypto_inst_setname(skcipher_crypto_instance(inst), tmpl->name,
614 				  cipher_alg);
615 	if (err)
616 		goto err_free_inst;
617 
618 	inst->free = skcipher_free_instance_simple;
619 
620 	/* Default algorithm properties, can be overridden */
621 	inst->alg.base.cra_blocksize = cipher_alg->cra_blocksize;
622 	inst->alg.base.cra_alignmask = cipher_alg->cra_alignmask;
623 	inst->alg.base.cra_priority = cipher_alg->cra_priority;
624 	inst->alg.min_keysize = cipher_alg->cra_cipher.cia_min_keysize;
625 	inst->alg.max_keysize = cipher_alg->cra_cipher.cia_max_keysize;
626 	inst->alg.ivsize = cipher_alg->cra_blocksize;
627 
628 	/* Use skcipher_ctx_simple by default, can be overridden */
629 	inst->alg.base.cra_ctxsize = sizeof(struct skcipher_ctx_simple);
630 	inst->alg.setkey = skcipher_setkey_simple;
631 	inst->alg.init = skcipher_init_tfm_simple;
632 	inst->alg.exit = skcipher_exit_tfm_simple;
633 
634 	return inst;
635 
636 err_free_inst:
637 	skcipher_free_instance_simple(inst);
638 	return ERR_PTR(err);
639 }
640 EXPORT_SYMBOL_GPL(skcipher_alloc_instance_simple);
641 
642 MODULE_LICENSE("GPL");
643 MODULE_DESCRIPTION("Symmetric key cipher type");
644 MODULE_IMPORT_NS("CRYPTO_INTERNAL");
645