xref: /linux/crypto/aead.c (revision 0d456bad36d42d16022be045c8a53ddbb59ee478) 
1 /*
2  * AEAD: Authenticated Encryption with Associated Data
3  *
4  * This file provides API support for AEAD algorithms.
5  *
6  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the Free
10  * Software Foundation; either version 2 of the License, or (at your option)
11  * any later version.
12  *
13  */
14 
15 #include <crypto/internal/aead.h>
16 #include <linux/err.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/rtnetlink.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/seq_file.h>
24 #include <linux/cryptouser.h>
25 #include <net/netlink.h>
26 
27 #include "internal.h"
28 
29 static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
30 			    unsigned int keylen)
31 {
32 	struct aead_alg *aead = crypto_aead_alg(tfm);
33 	unsigned long alignmask = crypto_aead_alignmask(tfm);
34 	int ret;
35 	u8 *buffer, *alignbuffer;
36 	unsigned long absize;
37 
38 	absize = keylen + alignmask;
39 	buffer = kmalloc(absize, GFP_ATOMIC);
40 	if (!buffer)
41 		return -ENOMEM;
42 
43 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
44 	memcpy(alignbuffer, key, keylen);
45 	ret = aead->setkey(tfm, alignbuffer, keylen);
46 	memset(alignbuffer, 0, keylen);
47 	kfree(buffer);
48 	return ret;
49 }
50 
51 static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
52 {
53 	struct aead_alg *aead = crypto_aead_alg(tfm);
54 	unsigned long alignmask = crypto_aead_alignmask(tfm);
55 
56 	if ((unsigned long)key & alignmask)
57 		return setkey_unaligned(tfm, key, keylen);
58 
59 	return aead->setkey(tfm, key, keylen);
60 }
61 
62 int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
63 {
64 	struct aead_tfm *crt = crypto_aead_crt(tfm);
65 	int err;
66 
67 	if (authsize > crypto_aead_alg(tfm)->maxauthsize)
68 		return -EINVAL;
69 
70 	if (crypto_aead_alg(tfm)->setauthsize) {
71 		err = crypto_aead_alg(tfm)->setauthsize(crt->base, authsize);
72 		if (err)
73 			return err;
74 	}
75 
76 	crypto_aead_crt(crt->base)->authsize = authsize;
77 	crt->authsize = authsize;
78 	return 0;
79 }
80 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
81 
82 static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
83 					u32 mask)
84 {
85 	return alg->cra_ctxsize;
86 }
87 
88 static int no_givcrypt(struct aead_givcrypt_request *req)
89 {
90 	return -ENOSYS;
91 }
92 
93 static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
94 {
95 	struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
96 	struct aead_tfm *crt = &tfm->crt_aead;
97 
98 	if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
99 		return -EINVAL;
100 
101 	crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
102 		      alg->setkey : setkey;
103 	crt->encrypt = alg->encrypt;
104 	crt->decrypt = alg->decrypt;
105 	crt->givencrypt = alg->givencrypt ?: no_givcrypt;
106 	crt->givdecrypt = alg->givdecrypt ?: no_givcrypt;
107 	crt->base = __crypto_aead_cast(tfm);
108 	crt->ivsize = alg->ivsize;
109 	crt->authsize = alg->maxauthsize;
110 
111 	return 0;
112 }
113 
114 #ifdef CONFIG_NET
115 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
116 {
117 	struct crypto_report_aead raead;
118 	struct aead_alg *aead = &alg->cra_aead;
119 
120 	snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "aead");
121 	snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s",
122 		 aead->geniv ?: "<built-in>");
123 
124 	raead.blocksize = alg->cra_blocksize;
125 	raead.maxauthsize = aead->maxauthsize;
126 	raead.ivsize = aead->ivsize;
127 
128 	if (nla_put(skb, CRYPTOCFGA_REPORT_AEAD,
129 		    sizeof(struct crypto_report_aead), &raead))
130 		goto nla_put_failure;
131 	return 0;
132 
133 nla_put_failure:
134 	return -EMSGSIZE;
135 }
136 #else
137 static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
138 {
139 	return -ENOSYS;
140 }
141 #endif
142 
143 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
144 	__attribute__ ((unused));
145 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
146 {
147 	struct aead_alg *aead = &alg->cra_aead;
148 
149 	seq_printf(m, "type         : aead\n");
150 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
151 					     "yes" : "no");
152 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
153 	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
154 	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
155 	seq_printf(m, "geniv        : %s\n", aead->geniv ?: "<built-in>");
156 }
157 
158 const struct crypto_type crypto_aead_type = {
159 	.ctxsize = crypto_aead_ctxsize,
160 	.init = crypto_init_aead_ops,
161 #ifdef CONFIG_PROC_FS
162 	.show = crypto_aead_show,
163 #endif
164 	.report = crypto_aead_report,
165 };
166 EXPORT_SYMBOL_GPL(crypto_aead_type);
167 
168 static int aead_null_givencrypt(struct aead_givcrypt_request *req)
169 {
170 	return crypto_aead_encrypt(&req->areq);
171 }
172 
173 static int aead_null_givdecrypt(struct aead_givcrypt_request *req)
174 {
175 	return crypto_aead_decrypt(&req->areq);
176 }
177 
178 static int crypto_init_nivaead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
179 {
180 	struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
181 	struct aead_tfm *crt = &tfm->crt_aead;
182 
183 	if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
184 		return -EINVAL;
185 
186 	crt->setkey = setkey;
187 	crt->encrypt = alg->encrypt;
188 	crt->decrypt = alg->decrypt;
189 	if (!alg->ivsize) {
190 		crt->givencrypt = aead_null_givencrypt;
191 		crt->givdecrypt = aead_null_givdecrypt;
192 	}
193 	crt->base = __crypto_aead_cast(tfm);
194 	crt->ivsize = alg->ivsize;
195 	crt->authsize = alg->maxauthsize;
196 
197 	return 0;
198 }
199 
200 #ifdef CONFIG_NET
201 static int crypto_nivaead_report(struct sk_buff *skb, struct crypto_alg *alg)
202 {
203 	struct crypto_report_aead raead;
204 	struct aead_alg *aead = &alg->cra_aead;
205 
206 	snprintf(raead.type, CRYPTO_MAX_ALG_NAME, "%s", "nivaead");
207 	snprintf(raead.geniv, CRYPTO_MAX_ALG_NAME, "%s", aead->geniv);
208 
209 	raead.blocksize = alg->cra_blocksize;
210 	raead.maxauthsize = aead->maxauthsize;
211 	raead.ivsize = aead->ivsize;
212 
213 	if (nla_put(skb, CRYPTOCFGA_REPORT_AEAD,
214 		    sizeof(struct crypto_report_aead), &raead))
215 		goto nla_put_failure;
216 	return 0;
217 
218 nla_put_failure:
219 	return -EMSGSIZE;
220 }
221 #else
222 static int crypto_nivaead_report(struct sk_buff *skb, struct crypto_alg *alg)
223 {
224 	return -ENOSYS;
225 }
226 #endif
227 
228 
229 static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
230 	__attribute__ ((unused));
231 static void crypto_nivaead_show(struct seq_file *m, struct crypto_alg *alg)
232 {
233 	struct aead_alg *aead = &alg->cra_aead;
234 
235 	seq_printf(m, "type         : nivaead\n");
236 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
237 					     "yes" : "no");
238 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
239 	seq_printf(m, "ivsize       : %u\n", aead->ivsize);
240 	seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
241 	seq_printf(m, "geniv        : %s\n", aead->geniv);
242 }
243 
244 const struct crypto_type crypto_nivaead_type = {
245 	.ctxsize = crypto_aead_ctxsize,
246 	.init = crypto_init_nivaead_ops,
247 #ifdef CONFIG_PROC_FS
248 	.show = crypto_nivaead_show,
249 #endif
250 	.report = crypto_nivaead_report,
251 };
252 EXPORT_SYMBOL_GPL(crypto_nivaead_type);
253 
254 static int crypto_grab_nivaead(struct crypto_aead_spawn *spawn,
255 			       const char *name, u32 type, u32 mask)
256 {
257 	struct crypto_alg *alg;
258 	int err;
259 
260 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
261 	type |= CRYPTO_ALG_TYPE_AEAD;
262 	mask |= CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV;
263 
264 	alg = crypto_alg_mod_lookup(name, type, mask);
265 	if (IS_ERR(alg))
266 		return PTR_ERR(alg);
267 
268 	err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
269 	crypto_mod_put(alg);
270 	return err;
271 }
272 
273 struct crypto_instance *aead_geniv_alloc(struct crypto_template *tmpl,
274 					 struct rtattr **tb, u32 type,
275 					 u32 mask)
276 {
277 	const char *name;
278 	struct crypto_aead_spawn *spawn;
279 	struct crypto_attr_type *algt;
280 	struct crypto_instance *inst;
281 	struct crypto_alg *alg;
282 	int err;
283 
284 	algt = crypto_get_attr_type(tb);
285 	err = PTR_ERR(algt);
286 	if (IS_ERR(algt))
287 		return ERR_PTR(err);
288 
289 	if ((algt->type ^ (CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV)) &
290 	    algt->mask)
291 		return ERR_PTR(-EINVAL);
292 
293 	name = crypto_attr_alg_name(tb[1]);
294 	err = PTR_ERR(name);
295 	if (IS_ERR(name))
296 		return ERR_PTR(err);
297 
298 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
299 	if (!inst)
300 		return ERR_PTR(-ENOMEM);
301 
302 	spawn = crypto_instance_ctx(inst);
303 
304 	/* Ignore async algorithms if necessary. */
305 	mask |= crypto_requires_sync(algt->type, algt->mask);
306 
307 	crypto_set_aead_spawn(spawn, inst);
308 	err = crypto_grab_nivaead(spawn, name, type, mask);
309 	if (err)
310 		goto err_free_inst;
311 
312 	alg = crypto_aead_spawn_alg(spawn);
313 
314 	err = -EINVAL;
315 	if (!alg->cra_aead.ivsize)
316 		goto err_drop_alg;
317 
318 	/*
319 	 * This is only true if we're constructing an algorithm with its
320 	 * default IV generator.  For the default generator we elide the
321 	 * template name and double-check the IV generator.
322 	 */
323 	if (algt->mask & CRYPTO_ALG_GENIV) {
324 		if (strcmp(tmpl->name, alg->cra_aead.geniv))
325 			goto err_drop_alg;
326 
327 		memcpy(inst->alg.cra_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
328 		memcpy(inst->alg.cra_driver_name, alg->cra_driver_name,
329 		       CRYPTO_MAX_ALG_NAME);
330 	} else {
331 		err = -ENAMETOOLONG;
332 		if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
333 			     "%s(%s)", tmpl->name, alg->cra_name) >=
334 		    CRYPTO_MAX_ALG_NAME)
335 			goto err_drop_alg;
336 		if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
337 			     "%s(%s)", tmpl->name, alg->cra_driver_name) >=
338 		    CRYPTO_MAX_ALG_NAME)
339 			goto err_drop_alg;
340 	}
341 
342 	inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV;
343 	inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
344 	inst->alg.cra_priority = alg->cra_priority;
345 	inst->alg.cra_blocksize = alg->cra_blocksize;
346 	inst->alg.cra_alignmask = alg->cra_alignmask;
347 	inst->alg.cra_type = &crypto_aead_type;
348 
349 	inst->alg.cra_aead.ivsize = alg->cra_aead.ivsize;
350 	inst->alg.cra_aead.maxauthsize = alg->cra_aead.maxauthsize;
351 	inst->alg.cra_aead.geniv = alg->cra_aead.geniv;
352 
353 	inst->alg.cra_aead.setkey = alg->cra_aead.setkey;
354 	inst->alg.cra_aead.setauthsize = alg->cra_aead.setauthsize;
355 	inst->alg.cra_aead.encrypt = alg->cra_aead.encrypt;
356 	inst->alg.cra_aead.decrypt = alg->cra_aead.decrypt;
357 
358 out:
359 	return inst;
360 
361 err_drop_alg:
362 	crypto_drop_aead(spawn);
363 err_free_inst:
364 	kfree(inst);
365 	inst = ERR_PTR(err);
366 	goto out;
367 }
368 EXPORT_SYMBOL_GPL(aead_geniv_alloc);
369 
370 void aead_geniv_free(struct crypto_instance *inst)
371 {
372 	crypto_drop_aead(crypto_instance_ctx(inst));
373 	kfree(inst);
374 }
375 EXPORT_SYMBOL_GPL(aead_geniv_free);
376 
377 int aead_geniv_init(struct crypto_tfm *tfm)
378 {
379 	struct crypto_instance *inst = (void *)tfm->__crt_alg;
380 	struct crypto_aead *aead;
381 
382 	aead = crypto_spawn_aead(crypto_instance_ctx(inst));
383 	if (IS_ERR(aead))
384 		return PTR_ERR(aead);
385 
386 	tfm->crt_aead.base = aead;
387 	tfm->crt_aead.reqsize += crypto_aead_reqsize(aead);
388 
389 	return 0;
390 }
391 EXPORT_SYMBOL_GPL(aead_geniv_init);
392 
393 void aead_geniv_exit(struct crypto_tfm *tfm)
394 {
395 	crypto_free_aead(tfm->crt_aead.base);
396 }
397 EXPORT_SYMBOL_GPL(aead_geniv_exit);
398 
399 static int crypto_nivaead_default(struct crypto_alg *alg, u32 type, u32 mask)
400 {
401 	struct rtattr *tb[3];
402 	struct {
403 		struct rtattr attr;
404 		struct crypto_attr_type data;
405 	} ptype;
406 	struct {
407 		struct rtattr attr;
408 		struct crypto_attr_alg data;
409 	} palg;
410 	struct crypto_template *tmpl;
411 	struct crypto_instance *inst;
412 	struct crypto_alg *larval;
413 	const char *geniv;
414 	int err;
415 
416 	larval = crypto_larval_lookup(alg->cra_driver_name,
417 				      CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_GENIV,
418 				      CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
419 	err = PTR_ERR(larval);
420 	if (IS_ERR(larval))
421 		goto out;
422 
423 	err = -EAGAIN;
424 	if (!crypto_is_larval(larval))
425 		goto drop_larval;
426 
427 	ptype.attr.rta_len = sizeof(ptype);
428 	ptype.attr.rta_type = CRYPTOA_TYPE;
429 	ptype.data.type = type | CRYPTO_ALG_GENIV;
430 	/* GENIV tells the template that we're making a default geniv. */
431 	ptype.data.mask = mask | CRYPTO_ALG_GENIV;
432 	tb[0] = &ptype.attr;
433 
434 	palg.attr.rta_len = sizeof(palg);
435 	palg.attr.rta_type = CRYPTOA_ALG;
436 	/* Must use the exact name to locate ourselves. */
437 	memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
438 	tb[1] = &palg.attr;
439 
440 	tb[2] = NULL;
441 
442 	geniv = alg->cra_aead.geniv;
443 
444 	tmpl = crypto_lookup_template(geniv);
445 	err = -ENOENT;
446 	if (!tmpl)
447 		goto kill_larval;
448 
449 	inst = tmpl->alloc(tb);
450 	err = PTR_ERR(inst);
451 	if (IS_ERR(inst))
452 		goto put_tmpl;
453 
454 	if ((err = crypto_register_instance(tmpl, inst))) {
455 		tmpl->free(inst);
456 		goto put_tmpl;
457 	}
458 
459 	/* Redo the lookup to use the instance we just registered. */
460 	err = -EAGAIN;
461 
462 put_tmpl:
463 	crypto_tmpl_put(tmpl);
464 kill_larval:
465 	crypto_larval_kill(larval);
466 drop_larval:
467 	crypto_mod_put(larval);
468 out:
469 	crypto_mod_put(alg);
470 	return err;
471 }
472 
473 struct crypto_alg *crypto_lookup_aead(const char *name, u32 type, u32 mask)
474 {
475 	struct crypto_alg *alg;
476 
477 	alg = crypto_alg_mod_lookup(name, type, mask);
478 	if (IS_ERR(alg))
479 		return alg;
480 
481 	if (alg->cra_type == &crypto_aead_type)
482 		return alg;
483 
484 	if (!alg->cra_aead.ivsize)
485 		return alg;
486 
487 	crypto_mod_put(alg);
488 	alg = crypto_alg_mod_lookup(name, type | CRYPTO_ALG_TESTED,
489 				    mask & ~CRYPTO_ALG_TESTED);
490 	if (IS_ERR(alg))
491 		return alg;
492 
493 	if (alg->cra_type == &crypto_aead_type) {
494 		if ((alg->cra_flags ^ type ^ ~mask) & CRYPTO_ALG_TESTED) {
495 			crypto_mod_put(alg);
496 			alg = ERR_PTR(-ENOENT);
497 		}
498 		return alg;
499 	}
500 
501 	BUG_ON(!alg->cra_aead.ivsize);
502 
503 	return ERR_PTR(crypto_nivaead_default(alg, type, mask));
504 }
505 EXPORT_SYMBOL_GPL(crypto_lookup_aead);
506 
507 int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
508 		     u32 type, u32 mask)
509 {
510 	struct crypto_alg *alg;
511 	int err;
512 
513 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
514 	type |= CRYPTO_ALG_TYPE_AEAD;
515 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
516 	mask |= CRYPTO_ALG_TYPE_MASK;
517 
518 	alg = crypto_lookup_aead(name, type, mask);
519 	if (IS_ERR(alg))
520 		return PTR_ERR(alg);
521 
522 	err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
523 	crypto_mod_put(alg);
524 	return err;
525 }
526 EXPORT_SYMBOL_GPL(crypto_grab_aead);
527 
528 struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
529 {
530 	struct crypto_tfm *tfm;
531 	int err;
532 
533 	type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
534 	type |= CRYPTO_ALG_TYPE_AEAD;
535 	mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
536 	mask |= CRYPTO_ALG_TYPE_MASK;
537 
538 	for (;;) {
539 		struct crypto_alg *alg;
540 
541 		alg = crypto_lookup_aead(alg_name, type, mask);
542 		if (IS_ERR(alg)) {
543 			err = PTR_ERR(alg);
544 			goto err;
545 		}
546 
547 		tfm = __crypto_alloc_tfm(alg, type, mask);
548 		if (!IS_ERR(tfm))
549 			return __crypto_aead_cast(tfm);
550 
551 		crypto_mod_put(alg);
552 		err = PTR_ERR(tfm);
553 
554 err:
555 		if (err != -EAGAIN)
556 			break;
557 		if (signal_pending(current)) {
558 			err = -EINTR;
559 			break;
560 		}
561 	}
562 
563 	return ERR_PTR(err);
564 }
565 EXPORT_SYMBOL_GPL(crypto_alloc_aead);
566 
567 MODULE_LICENSE("GPL");
568 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");
569