xref: /openbmc/linux/crypto/algapi.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * Cryptographic API for algorithms (i.e., low-level API).
3  *
4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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 
13 #include <linux/err.h>
14 #include <linux/errno.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/list.h>
18 #include <linux/module.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/string.h>
21 
22 #include "internal.h"
23 
24 static LIST_HEAD(crypto_template_list);
25 
26 void crypto_larval_error(const char *name, u32 type, u32 mask)
27 {
28 	struct crypto_alg *alg;
29 
30 	down_read(&crypto_alg_sem);
31 	alg = __crypto_alg_lookup(name, type, mask);
32 	up_read(&crypto_alg_sem);
33 
34 	if (alg) {
35 		if (crypto_is_larval(alg)) {
36 			struct crypto_larval *larval = (void *)alg;
37 			complete(&larval->completion);
38 		}
39 		crypto_mod_put(alg);
40 	}
41 }
42 EXPORT_SYMBOL_GPL(crypto_larval_error);
43 
44 static inline int crypto_set_driver_name(struct crypto_alg *alg)
45 {
46 	static const char suffix[] = "-generic";
47 	char *driver_name = alg->cra_driver_name;
48 	int len;
49 
50 	if (*driver_name)
51 		return 0;
52 
53 	len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
54 	if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
55 		return -ENAMETOOLONG;
56 
57 	memcpy(driver_name + len, suffix, sizeof(suffix));
58 	return 0;
59 }
60 
61 static int crypto_check_alg(struct crypto_alg *alg)
62 {
63 	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
64 		return -EINVAL;
65 
66 	if (alg->cra_alignmask & alg->cra_blocksize)
67 		return -EINVAL;
68 
69 	if (alg->cra_blocksize > PAGE_SIZE / 8)
70 		return -EINVAL;
71 
72 	if (alg->cra_priority < 0)
73 		return -EINVAL;
74 
75 	return crypto_set_driver_name(alg);
76 }
77 
78 static void crypto_destroy_instance(struct crypto_alg *alg)
79 {
80 	struct crypto_instance *inst = (void *)alg;
81 	struct crypto_template *tmpl = inst->tmpl;
82 
83 	tmpl->free(inst);
84 	crypto_tmpl_put(tmpl);
85 }
86 
87 static void crypto_remove_spawn(struct crypto_spawn *spawn,
88 				struct list_head *list,
89 				struct list_head *secondary_spawns)
90 {
91 	struct crypto_instance *inst = spawn->inst;
92 	struct crypto_template *tmpl = inst->tmpl;
93 
94 	list_del_init(&spawn->list);
95 	spawn->alg = NULL;
96 
97 	if (crypto_is_dead(&inst->alg))
98 		return;
99 
100 	inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
101 	if (!tmpl || !crypto_tmpl_get(tmpl))
102 		return;
103 
104 	crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
105 	list_move(&inst->alg.cra_list, list);
106 	hlist_del(&inst->list);
107 	inst->alg.cra_destroy = crypto_destroy_instance;
108 
109 	list_splice(&inst->alg.cra_users, secondary_spawns);
110 }
111 
112 static void crypto_remove_spawns(struct list_head *spawns,
113 				 struct list_head *list, u32 new_type)
114 {
115 	struct crypto_spawn *spawn, *n;
116 	LIST_HEAD(secondary_spawns);
117 
118 	list_for_each_entry_safe(spawn, n, spawns, list) {
119 		if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)
120 			continue;
121 
122 		crypto_remove_spawn(spawn, list, &secondary_spawns);
123 	}
124 
125 	while (!list_empty(&secondary_spawns)) {
126 		list_for_each_entry_safe(spawn, n, &secondary_spawns, list)
127 			crypto_remove_spawn(spawn, list, &secondary_spawns);
128 	}
129 }
130 
131 static int __crypto_register_alg(struct crypto_alg *alg,
132 				 struct list_head *list)
133 {
134 	struct crypto_alg *q;
135 	int ret = -EAGAIN;
136 
137 	if (crypto_is_dead(alg))
138 		goto out;
139 
140 	INIT_LIST_HEAD(&alg->cra_users);
141 
142 	ret = -EEXIST;
143 
144 	atomic_set(&alg->cra_refcnt, 1);
145 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
146 		if (q == alg)
147 			goto out;
148 
149 		if (crypto_is_moribund(q))
150 			continue;
151 
152 		if (crypto_is_larval(q)) {
153 			struct crypto_larval *larval = (void *)q;
154 
155 			if (strcmp(alg->cra_name, q->cra_name) &&
156 			    strcmp(alg->cra_driver_name, q->cra_name))
157 				continue;
158 
159 			if (larval->adult)
160 				continue;
161 			if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
162 				continue;
163 			if (!crypto_mod_get(alg))
164 				continue;
165 
166 			larval->adult = alg;
167 			complete(&larval->completion);
168 			continue;
169 		}
170 
171 		if (strcmp(alg->cra_name, q->cra_name))
172 			continue;
173 
174 		if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
175 		    q->cra_priority > alg->cra_priority)
176 			continue;
177 
178 		crypto_remove_spawns(&q->cra_users, list, alg->cra_flags);
179 	}
180 
181 	list_add(&alg->cra_list, &crypto_alg_list);
182 
183 	crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
184 	ret = 0;
185 
186 out:
187 	return ret;
188 }
189 
190 static void crypto_remove_final(struct list_head *list)
191 {
192 	struct crypto_alg *alg;
193 	struct crypto_alg *n;
194 
195 	list_for_each_entry_safe(alg, n, list, cra_list) {
196 		list_del_init(&alg->cra_list);
197 		crypto_alg_put(alg);
198 	}
199 }
200 
201 int crypto_register_alg(struct crypto_alg *alg)
202 {
203 	LIST_HEAD(list);
204 	int err;
205 
206 	err = crypto_check_alg(alg);
207 	if (err)
208 		return err;
209 
210 	down_write(&crypto_alg_sem);
211 	err = __crypto_register_alg(alg, &list);
212 	up_write(&crypto_alg_sem);
213 
214 	crypto_remove_final(&list);
215 	return err;
216 }
217 EXPORT_SYMBOL_GPL(crypto_register_alg);
218 
219 static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
220 {
221 	if (unlikely(list_empty(&alg->cra_list)))
222 		return -ENOENT;
223 
224 	alg->cra_flags |= CRYPTO_ALG_DEAD;
225 
226 	crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
227 	list_del_init(&alg->cra_list);
228 	crypto_remove_spawns(&alg->cra_users, list, alg->cra_flags);
229 
230 	return 0;
231 }
232 
233 int crypto_unregister_alg(struct crypto_alg *alg)
234 {
235 	int ret;
236 	LIST_HEAD(list);
237 
238 	down_write(&crypto_alg_sem);
239 	ret = crypto_remove_alg(alg, &list);
240 	up_write(&crypto_alg_sem);
241 
242 	if (ret)
243 		return ret;
244 
245 	BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
246 	if (alg->cra_destroy)
247 		alg->cra_destroy(alg);
248 
249 	crypto_remove_final(&list);
250 	return 0;
251 }
252 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
253 
254 int crypto_register_template(struct crypto_template *tmpl)
255 {
256 	struct crypto_template *q;
257 	int err = -EEXIST;
258 
259 	down_write(&crypto_alg_sem);
260 
261 	list_for_each_entry(q, &crypto_template_list, list) {
262 		if (q == tmpl)
263 			goto out;
264 	}
265 
266 	list_add(&tmpl->list, &crypto_template_list);
267 	crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
268 	err = 0;
269 out:
270 	up_write(&crypto_alg_sem);
271 	return err;
272 }
273 EXPORT_SYMBOL_GPL(crypto_register_template);
274 
275 void crypto_unregister_template(struct crypto_template *tmpl)
276 {
277 	struct crypto_instance *inst;
278 	struct hlist_node *p, *n;
279 	struct hlist_head *list;
280 	LIST_HEAD(users);
281 
282 	down_write(&crypto_alg_sem);
283 
284 	BUG_ON(list_empty(&tmpl->list));
285 	list_del_init(&tmpl->list);
286 
287 	list = &tmpl->instances;
288 	hlist_for_each_entry(inst, p, list, list) {
289 		int err = crypto_remove_alg(&inst->alg, &users);
290 		BUG_ON(err);
291 	}
292 
293 	crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
294 
295 	up_write(&crypto_alg_sem);
296 
297 	hlist_for_each_entry_safe(inst, p, n, list, list) {
298 		BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
299 		tmpl->free(inst);
300 	}
301 	crypto_remove_final(&users);
302 }
303 EXPORT_SYMBOL_GPL(crypto_unregister_template);
304 
305 static struct crypto_template *__crypto_lookup_template(const char *name)
306 {
307 	struct crypto_template *q, *tmpl = NULL;
308 
309 	down_read(&crypto_alg_sem);
310 	list_for_each_entry(q, &crypto_template_list, list) {
311 		if (strcmp(q->name, name))
312 			continue;
313 		if (unlikely(!crypto_tmpl_get(q)))
314 			continue;
315 
316 		tmpl = q;
317 		break;
318 	}
319 	up_read(&crypto_alg_sem);
320 
321 	return tmpl;
322 }
323 
324 struct crypto_template *crypto_lookup_template(const char *name)
325 {
326 	return try_then_request_module(__crypto_lookup_template(name), name);
327 }
328 EXPORT_SYMBOL_GPL(crypto_lookup_template);
329 
330 int crypto_register_instance(struct crypto_template *tmpl,
331 			     struct crypto_instance *inst)
332 {
333 	LIST_HEAD(list);
334 	int err = -EINVAL;
335 
336 	if (inst->alg.cra_destroy)
337 		goto err;
338 
339 	err = crypto_check_alg(&inst->alg);
340 	if (err)
341 		goto err;
342 
343 	inst->alg.cra_module = tmpl->module;
344 
345 	down_write(&crypto_alg_sem);
346 
347 	err = __crypto_register_alg(&inst->alg, &list);
348 	if (err)
349 		goto unlock;
350 
351 	hlist_add_head(&inst->list, &tmpl->instances);
352 	inst->tmpl = tmpl;
353 
354 unlock:
355 	up_write(&crypto_alg_sem);
356 
357 	crypto_remove_final(&list);
358 
359 err:
360 	return err;
361 }
362 EXPORT_SYMBOL_GPL(crypto_register_instance);
363 
364 int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
365 		      struct crypto_instance *inst, u32 mask)
366 {
367 	int err = -EAGAIN;
368 
369 	spawn->inst = inst;
370 	spawn->mask = mask;
371 
372 	down_write(&crypto_alg_sem);
373 	if (!crypto_is_moribund(alg)) {
374 		list_add(&spawn->list, &alg->cra_users);
375 		spawn->alg = alg;
376 		err = 0;
377 	}
378 	up_write(&crypto_alg_sem);
379 
380 	return err;
381 }
382 EXPORT_SYMBOL_GPL(crypto_init_spawn);
383 
384 void crypto_drop_spawn(struct crypto_spawn *spawn)
385 {
386 	down_write(&crypto_alg_sem);
387 	list_del(&spawn->list);
388 	up_write(&crypto_alg_sem);
389 }
390 EXPORT_SYMBOL_GPL(crypto_drop_spawn);
391 
392 struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,
393 				    u32 mask)
394 {
395 	struct crypto_alg *alg;
396 	struct crypto_alg *alg2;
397 	struct crypto_tfm *tfm;
398 
399 	down_read(&crypto_alg_sem);
400 	alg = spawn->alg;
401 	alg2 = alg;
402 	if (alg2)
403 		alg2 = crypto_mod_get(alg2);
404 	up_read(&crypto_alg_sem);
405 
406 	if (!alg2) {
407 		if (alg)
408 			crypto_shoot_alg(alg);
409 		return ERR_PTR(-EAGAIN);
410 	}
411 
412 	tfm = ERR_PTR(-EINVAL);
413 	if (unlikely((alg->cra_flags ^ type) & mask))
414 		goto out_put_alg;
415 
416 	tfm = __crypto_alloc_tfm(alg, type, mask);
417 	if (IS_ERR(tfm))
418 		goto out_put_alg;
419 
420 	return tfm;
421 
422 out_put_alg:
423 	crypto_mod_put(alg);
424 	return tfm;
425 }
426 EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
427 
428 int crypto_register_notifier(struct notifier_block *nb)
429 {
430 	return blocking_notifier_chain_register(&crypto_chain, nb);
431 }
432 EXPORT_SYMBOL_GPL(crypto_register_notifier);
433 
434 int crypto_unregister_notifier(struct notifier_block *nb)
435 {
436 	return blocking_notifier_chain_unregister(&crypto_chain, nb);
437 }
438 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
439 
440 struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb)
441 {
442 	struct rtattr *rta = tb[CRYPTOA_TYPE - 1];
443 	struct crypto_attr_type *algt;
444 
445 	if (!rta)
446 		return ERR_PTR(-ENOENT);
447 	if (RTA_PAYLOAD(rta) < sizeof(*algt))
448 		return ERR_PTR(-EINVAL);
449 
450 	algt = RTA_DATA(rta);
451 
452 	return algt;
453 }
454 EXPORT_SYMBOL_GPL(crypto_get_attr_type);
455 
456 int crypto_check_attr_type(struct rtattr **tb, u32 type)
457 {
458 	struct crypto_attr_type *algt;
459 
460 	algt = crypto_get_attr_type(tb);
461 	if (IS_ERR(algt))
462 		return PTR_ERR(algt);
463 
464 	if ((algt->type ^ type) & algt->mask)
465 		return -EINVAL;
466 
467 	return 0;
468 }
469 EXPORT_SYMBOL_GPL(crypto_check_attr_type);
470 
471 struct crypto_alg *crypto_get_attr_alg(struct rtattr **tb, u32 type, u32 mask)
472 {
473 	struct rtattr *rta = tb[CRYPTOA_ALG - 1];
474 	struct crypto_attr_alg *alga;
475 
476 	if (!rta)
477 		return ERR_PTR(-ENOENT);
478 	if (RTA_PAYLOAD(rta) < sizeof(*alga))
479 		return ERR_PTR(-EINVAL);
480 
481 	alga = RTA_DATA(rta);
482 	alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;
483 
484 	return crypto_alg_mod_lookup(alga->name, type, mask);
485 }
486 EXPORT_SYMBOL_GPL(crypto_get_attr_alg);
487 
488 struct crypto_instance *crypto_alloc_instance(const char *name,
489 					      struct crypto_alg *alg)
490 {
491 	struct crypto_instance *inst;
492 	struct crypto_spawn *spawn;
493 	int err;
494 
495 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
496 	if (!inst)
497 		return ERR_PTR(-ENOMEM);
498 
499 	err = -ENAMETOOLONG;
500 	if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", name,
501 		     alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
502 		goto err_free_inst;
503 
504 	if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
505 		     name, alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
506 		goto err_free_inst;
507 
508 	spawn = crypto_instance_ctx(inst);
509 	err = crypto_init_spawn(spawn, alg, inst,
510 				CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
511 
512 	if (err)
513 		goto err_free_inst;
514 
515 	return inst;
516 
517 err_free_inst:
518 	kfree(inst);
519 	return ERR_PTR(err);
520 }
521 EXPORT_SYMBOL_GPL(crypto_alloc_instance);
522 
523 void crypto_init_queue(struct crypto_queue *queue, unsigned int max_qlen)
524 {
525 	INIT_LIST_HEAD(&queue->list);
526 	queue->backlog = &queue->list;
527 	queue->qlen = 0;
528 	queue->max_qlen = max_qlen;
529 }
530 EXPORT_SYMBOL_GPL(crypto_init_queue);
531 
532 int crypto_enqueue_request(struct crypto_queue *queue,
533 			   struct crypto_async_request *request)
534 {
535 	int err = -EINPROGRESS;
536 
537 	if (unlikely(queue->qlen >= queue->max_qlen)) {
538 		err = -EBUSY;
539 		if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
540 			goto out;
541 		if (queue->backlog == &queue->list)
542 			queue->backlog = &request->list;
543 	}
544 
545 	queue->qlen++;
546 	list_add_tail(&request->list, &queue->list);
547 
548 out:
549 	return err;
550 }
551 EXPORT_SYMBOL_GPL(crypto_enqueue_request);
552 
553 struct crypto_async_request *crypto_dequeue_request(struct crypto_queue *queue)
554 {
555 	struct list_head *request;
556 
557 	if (unlikely(!queue->qlen))
558 		return NULL;
559 
560 	queue->qlen--;
561 
562 	if (queue->backlog != &queue->list)
563 		queue->backlog = queue->backlog->next;
564 
565 	request = queue->list.next;
566 	list_del(request);
567 
568 	return list_entry(request, struct crypto_async_request, list);
569 }
570 EXPORT_SYMBOL_GPL(crypto_dequeue_request);
571 
572 int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm)
573 {
574 	struct crypto_async_request *req;
575 
576 	list_for_each_entry(req, &queue->list, list) {
577 		if (req->tfm == tfm)
578 			return 1;
579 	}
580 
581 	return 0;
582 }
583 EXPORT_SYMBOL_GPL(crypto_tfm_in_queue);
584 
585 static int __init crypto_algapi_init(void)
586 {
587 	crypto_init_proc();
588 	return 0;
589 }
590 
591 static void __exit crypto_algapi_exit(void)
592 {
593 	crypto_exit_proc();
594 }
595 
596 module_init(crypto_algapi_init);
597 module_exit(crypto_algapi_exit);
598 
599 MODULE_LICENSE("GPL");
600 MODULE_DESCRIPTION("Cryptographic algorithms API");
601