xref: /openbmc/linux/crypto/skcipher.c (revision 80483c3a) 
1 /*
2  * Symmetric key cipher operations.
3  *
4  * Generic encrypt/decrypt wrapper for ciphers, handles operations across
5  * multiple page boundaries by using temporary blocks.  In user context,
6  * the kernel is given a chance to schedule us once per page.
7  *
8  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
9  *
10  * This program is free software; you can redistribute it and/or modify it
11  * under the terms of the GNU General Public License as published by the Free
12  * Software Foundation; either version 2 of the License, or (at your option)
13  * any later version.
14  *
15  */
16 
17 #include <crypto/internal/skcipher.h>
18 #include <linux/bug.h>
19 #include <linux/cryptouser.h>
20 #include <linux/module.h>
21 #include <linux/rtnetlink.h>
22 #include <linux/seq_file.h>
23 #include <net/netlink.h>
24 
25 #include "internal.h"
26 
27 static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
28 {
29 	if (alg->cra_type == &crypto_blkcipher_type)
30 		return sizeof(struct crypto_blkcipher *);
31 
32 	if (alg->cra_type == &crypto_ablkcipher_type ||
33 	    alg->cra_type == &crypto_givcipher_type)
34 		return sizeof(struct crypto_ablkcipher *);
35 
36 	return crypto_alg_extsize(alg);
37 }
38 
39 static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
40 				     const u8 *key, unsigned int keylen)
41 {
42 	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
43 	struct crypto_blkcipher *blkcipher = *ctx;
44 	int err;
45 
46 	crypto_blkcipher_clear_flags(blkcipher, ~0);
47 	crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
48 					      CRYPTO_TFM_REQ_MASK);
49 	err = crypto_blkcipher_setkey(blkcipher, key, keylen);
50 	crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
51 				       CRYPTO_TFM_RES_MASK);
52 
53 	return err;
54 }
55 
56 static int skcipher_crypt_blkcipher(struct skcipher_request *req,
57 				    int (*crypt)(struct blkcipher_desc *,
58 						 struct scatterlist *,
59 						 struct scatterlist *,
60 						 unsigned int))
61 {
62 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
63 	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
64 	struct blkcipher_desc desc = {
65 		.tfm = *ctx,
66 		.info = req->iv,
67 		.flags = req->base.flags,
68 	};
69 
70 
71 	return crypt(&desc, req->dst, req->src, req->cryptlen);
72 }
73 
74 static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
75 {
76 	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
77 	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
78 	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
79 
80 	return skcipher_crypt_blkcipher(req, alg->encrypt);
81 }
82 
83 static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
84 {
85 	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
86 	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
87 	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
88 
89 	return skcipher_crypt_blkcipher(req, alg->decrypt);
90 }
91 
92 static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
93 {
94 	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
95 
96 	crypto_free_blkcipher(*ctx);
97 }
98 
99 static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
100 {
101 	struct crypto_alg *calg = tfm->__crt_alg;
102 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
103 	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
104 	struct crypto_blkcipher *blkcipher;
105 	struct crypto_tfm *btfm;
106 
107 	if (!crypto_mod_get(calg))
108 		return -EAGAIN;
109 
110 	btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
111 					CRYPTO_ALG_TYPE_MASK);
112 	if (IS_ERR(btfm)) {
113 		crypto_mod_put(calg);
114 		return PTR_ERR(btfm);
115 	}
116 
117 	blkcipher = __crypto_blkcipher_cast(btfm);
118 	*ctx = blkcipher;
119 	tfm->exit = crypto_exit_skcipher_ops_blkcipher;
120 
121 	skcipher->setkey = skcipher_setkey_blkcipher;
122 	skcipher->encrypt = skcipher_encrypt_blkcipher;
123 	skcipher->decrypt = skcipher_decrypt_blkcipher;
124 
125 	skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);
126 	skcipher->keysize = calg->cra_blkcipher.max_keysize;
127 
128 	return 0;
129 }
130 
131 static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
132 				      const u8 *key, unsigned int keylen)
133 {
134 	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
135 	struct crypto_ablkcipher *ablkcipher = *ctx;
136 	int err;
137 
138 	crypto_ablkcipher_clear_flags(ablkcipher, ~0);
139 	crypto_ablkcipher_set_flags(ablkcipher,
140 				    crypto_skcipher_get_flags(tfm) &
141 				    CRYPTO_TFM_REQ_MASK);
142 	err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
143 	crypto_skcipher_set_flags(tfm,
144 				  crypto_ablkcipher_get_flags(ablkcipher) &
145 				  CRYPTO_TFM_RES_MASK);
146 
147 	return err;
148 }
149 
150 static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
151 				     int (*crypt)(struct ablkcipher_request *))
152 {
153 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
154 	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
155 	struct ablkcipher_request *subreq = skcipher_request_ctx(req);
156 
157 	ablkcipher_request_set_tfm(subreq, *ctx);
158 	ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
159 					req->base.complete, req->base.data);
160 	ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
161 				     req->iv);
162 
163 	return crypt(subreq);
164 }
165 
166 static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
167 {
168 	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
169 	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
170 	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
171 
172 	return skcipher_crypt_ablkcipher(req, alg->encrypt);
173 }
174 
175 static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
176 {
177 	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
178 	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
179 	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
180 
181 	return skcipher_crypt_ablkcipher(req, alg->decrypt);
182 }
183 
184 static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
185 {
186 	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
187 
188 	crypto_free_ablkcipher(*ctx);
189 }
190 
191 static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
192 {
193 	struct crypto_alg *calg = tfm->__crt_alg;
194 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
195 	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
196 	struct crypto_ablkcipher *ablkcipher;
197 	struct crypto_tfm *abtfm;
198 
199 	if (!crypto_mod_get(calg))
200 		return -EAGAIN;
201 
202 	abtfm = __crypto_alloc_tfm(calg, 0, 0);
203 	if (IS_ERR(abtfm)) {
204 		crypto_mod_put(calg);
205 		return PTR_ERR(abtfm);
206 	}
207 
208 	ablkcipher = __crypto_ablkcipher_cast(abtfm);
209 	*ctx = ablkcipher;
210 	tfm->exit = crypto_exit_skcipher_ops_ablkcipher;
211 
212 	skcipher->setkey = skcipher_setkey_ablkcipher;
213 	skcipher->encrypt = skcipher_encrypt_ablkcipher;
214 	skcipher->decrypt = skcipher_decrypt_ablkcipher;
215 
216 	skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
217 	skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
218 			    sizeof(struct ablkcipher_request);
219 	skcipher->keysize = calg->cra_ablkcipher.max_keysize;
220 
221 	return 0;
222 }
223 
224 static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
225 {
226 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
227 	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
228 
229 	alg->exit(skcipher);
230 }
231 
232 static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
233 {
234 	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
235 	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
236 
237 	if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
238 		return crypto_init_skcipher_ops_blkcipher(tfm);
239 
240 	if (tfm->__crt_alg->cra_type == &crypto_ablkcipher_type ||
241 	    tfm->__crt_alg->cra_type == &crypto_givcipher_type)
242 		return crypto_init_skcipher_ops_ablkcipher(tfm);
243 
244 	skcipher->setkey = alg->setkey;
245 	skcipher->encrypt = alg->encrypt;
246 	skcipher->decrypt = alg->decrypt;
247 	skcipher->ivsize = alg->ivsize;
248 	skcipher->keysize = alg->max_keysize;
249 
250 	if (alg->exit)
251 		skcipher->base.exit = crypto_skcipher_exit_tfm;
252 
253 	if (alg->init)
254 		return alg->init(skcipher);
255 
256 	return 0;
257 }
258 
259 static void crypto_skcipher_free_instance(struct crypto_instance *inst)
260 {
261 	struct skcipher_instance *skcipher =
262 		container_of(inst, struct skcipher_instance, s.base);
263 
264 	skcipher->free(skcipher);
265 }
266 
267 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
268 	__attribute__ ((unused));
269 static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
270 {
271 	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
272 						     base);
273 
274 	seq_printf(m, "type         : skcipher\n");
275 	seq_printf(m, "async        : %s\n",
276 		   alg->cra_flags & CRYPTO_ALG_ASYNC ?  "yes" : "no");
277 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
278 	seq_printf(m, "min keysize  : %u\n", skcipher->min_keysize);
279 	seq_printf(m, "max keysize  : %u\n", skcipher->max_keysize);
280 	seq_printf(m, "ivsize       : %u\n", skcipher->ivsize);
281 	seq_printf(m, "chunksize    : %u\n", skcipher->chunksize);
282 }
283 
284 #ifdef CONFIG_NET
285 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
286 {
287 	struct crypto_report_blkcipher rblkcipher;
288 	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
289 						     base);
290 
291 	strncpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
292 	strncpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
293 
294 	rblkcipher.blocksize = alg->cra_blocksize;
295 	rblkcipher.min_keysize = skcipher->min_keysize;
296 	rblkcipher.max_keysize = skcipher->max_keysize;
297 	rblkcipher.ivsize = skcipher->ivsize;
298 
299 	if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
300 		    sizeof(struct crypto_report_blkcipher), &rblkcipher))
301 		goto nla_put_failure;
302 	return 0;
303 
304 nla_put_failure:
305 	return -EMSGSIZE;
306 }
307 #else
308 static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
309 {
310 	return -ENOSYS;
311 }
312 #endif
313 
314 static const struct crypto_type crypto_skcipher_type2 = {
315 	.extsize = crypto_skcipher_extsize,
316 	.init_tfm = crypto_skcipher_init_tfm,
317 	.free = crypto_skcipher_free_instance,
318 #ifdef CONFIG_PROC_FS
319 	.show = crypto_skcipher_show,
320 #endif
321 	.report = crypto_skcipher_report,
322 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
323 	.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,
324 	.type = CRYPTO_ALG_TYPE_SKCIPHER,
325 	.tfmsize = offsetof(struct crypto_skcipher, base),
326 };
327 
328 int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,
329 			  const char *name, u32 type, u32 mask)
330 {
331 	spawn->base.frontend = &crypto_skcipher_type2;
332 	return crypto_grab_spawn(&spawn->base, name, type, mask);
333 }
334 EXPORT_SYMBOL_GPL(crypto_grab_skcipher);
335 
336 struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
337 					      u32 type, u32 mask)
338 {
339 	return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
340 }
341 EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);
342 
343 int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask)
344 {
345 	return crypto_type_has_alg(alg_name, &crypto_skcipher_type2,
346 				   type, mask);
347 }
348 EXPORT_SYMBOL_GPL(crypto_has_skcipher2);
349 
350 static int skcipher_prepare_alg(struct skcipher_alg *alg)
351 {
352 	struct crypto_alg *base = &alg->base;
353 
354 	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
355 		return -EINVAL;
356 
357 	if (!alg->chunksize)
358 		alg->chunksize = base->cra_blocksize;
359 
360 	base->cra_type = &crypto_skcipher_type2;
361 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
362 	base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
363 
364 	return 0;
365 }
366 
367 int crypto_register_skcipher(struct skcipher_alg *alg)
368 {
369 	struct crypto_alg *base = &alg->base;
370 	int err;
371 
372 	err = skcipher_prepare_alg(alg);
373 	if (err)
374 		return err;
375 
376 	return crypto_register_alg(base);
377 }
378 EXPORT_SYMBOL_GPL(crypto_register_skcipher);
379 
380 void crypto_unregister_skcipher(struct skcipher_alg *alg)
381 {
382 	crypto_unregister_alg(&alg->base);
383 }
384 EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
385 
386 int crypto_register_skciphers(struct skcipher_alg *algs, int count)
387 {
388 	int i, ret;
389 
390 	for (i = 0; i < count; i++) {
391 		ret = crypto_register_skcipher(&algs[i]);
392 		if (ret)
393 			goto err;
394 	}
395 
396 	return 0;
397 
398 err:
399 	for (--i; i >= 0; --i)
400 		crypto_unregister_skcipher(&algs[i]);
401 
402 	return ret;
403 }
404 EXPORT_SYMBOL_GPL(crypto_register_skciphers);
405 
406 void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
407 {
408 	int i;
409 
410 	for (i = count - 1; i >= 0; --i)
411 		crypto_unregister_skcipher(&algs[i]);
412 }
413 EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
414 
415 int skcipher_register_instance(struct crypto_template *tmpl,
416 			   struct skcipher_instance *inst)
417 {
418 	int err;
419 
420 	err = skcipher_prepare_alg(&inst->alg);
421 	if (err)
422 		return err;
423 
424 	return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
425 }
426 EXPORT_SYMBOL_GPL(skcipher_register_instance);
427 
428 MODULE_LICENSE("GPL");
429 MODULE_DESCRIPTION("Symmetric key cipher type");
430