1/*
2 * Scatterlist Cryptographic API.
3 *
4 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
5 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
6 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
7 *
8 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
9 * and Nettle, by Niels M��ller.
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 *
16 */
17
18#include <linux/err.h>
19#include <linux/errno.h>
20#include <linux/kernel.h>
21#include <linux/kmod.h>
22#include <linux/module.h>
23#include <linux/param.h>
24#include <linux/sched.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include "internal.h"
28
29LIST_HEAD(crypto_alg_list);
30EXPORT_SYMBOL_GPL(crypto_alg_list);
31DECLARE_RWSEM(crypto_alg_sem);
32EXPORT_SYMBOL_GPL(crypto_alg_sem);
33
34BLOCKING_NOTIFIER_HEAD(crypto_chain);
35EXPORT_SYMBOL_GPL(crypto_chain);
36
37static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
38{
39	atomic_inc(&alg->cra_refcnt);
40	return alg;
41}
42
43struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
44{
45	return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
46}
47EXPORT_SYMBOL_GPL(crypto_mod_get);
48
49void crypto_mod_put(struct crypto_alg *alg)
50{
51	struct module *module = alg->cra_module;
52
53	crypto_alg_put(alg);
54	module_put(module);
55}
56EXPORT_SYMBOL_GPL(crypto_mod_put);
57
58static inline int crypto_is_test_larval(struct crypto_larval *larval)
59{
60	return larval->alg.cra_driver_name[0];
61}
62
63static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
64					      u32 mask)
65{
66	struct crypto_alg *q, *alg = NULL;
67	int best = -2;
68
69	list_for_each_entry(q, &crypto_alg_list, cra_list) {
70		int exact, fuzzy;
71
72		if (crypto_is_moribund(q))
73			continue;
74
75		if ((q->cra_flags ^ type) & mask)
76			continue;
77
78		if (crypto_is_larval(q) &&
79		    !crypto_is_test_larval((struct crypto_larval *)q) &&
80		    ((struct crypto_larval *)q)->mask != mask)
81			continue;
82
83		exact = !strcmp(q->cra_driver_name, name);
84		fuzzy = !strcmp(q->cra_name, name);
85		if (!exact && !(fuzzy && q->cra_priority > best))
86			continue;
87
88		if (unlikely(!crypto_mod_get(q)))
89			continue;
90
91		best = q->cra_priority;
92		if (alg)
93			crypto_mod_put(alg);
94		alg = q;
95
96		if (exact)
97			break;
98	}
99
100	return alg;
101}
102
103static void crypto_larval_destroy(struct crypto_alg *alg)
104{
105	struct crypto_larval *larval = (void *)alg;
106
107	BUG_ON(!crypto_is_larval(alg));
108	if (larval->adult)
109		crypto_mod_put(larval->adult);
110	kfree(larval);
111}
112
113struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
114{
115	struct crypto_larval *larval;
116
117	larval = kzalloc(sizeof(*larval), GFP_KERNEL);
118	if (!larval)
119		return ERR_PTR(-ENOMEM);
120
121	larval->mask = mask;
122	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
123	larval->alg.cra_priority = -1;
124	larval->alg.cra_destroy = crypto_larval_destroy;
125
126	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
127	init_completion(&larval->completion);
128
129	return larval;
130}
131EXPORT_SYMBOL_GPL(crypto_larval_alloc);
132
133static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
134					    u32 mask)
135{
136	struct crypto_alg *alg;
137	struct crypto_larval *larval;
138
139	larval = crypto_larval_alloc(name, type, mask);
140	if (IS_ERR(larval))
141		return ERR_CAST(larval);
142
143	atomic_set(&larval->alg.cra_refcnt, 2);
144
145	down_write(&crypto_alg_sem);
146	alg = __crypto_alg_lookup(name, type, mask);
147	if (!alg) {
148		alg = &larval->alg;
149		list_add(&alg->cra_list, &crypto_alg_list);
150	}
151	up_write(&crypto_alg_sem);
152
153	if (alg != &larval->alg)
154		kfree(larval);
155
156	return alg;
157}
158
159void crypto_larval_kill(struct crypto_alg *alg)
160{
161	struct crypto_larval *larval = (void *)alg;
162
163	down_write(&crypto_alg_sem);
164	list_del(&alg->cra_list);
165	up_write(&crypto_alg_sem);
166	complete_all(&larval->completion);
167	crypto_alg_put(alg);
168}
169EXPORT_SYMBOL_GPL(crypto_larval_kill);
170
171static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
172{
173	struct crypto_larval *larval = (void *)alg;
174	long timeout;
175
176	timeout = wait_for_completion_interruptible_timeout(
177		&larval->completion, 60 * HZ);
178
179	alg = larval->adult;
180	if (timeout < 0)
181		alg = ERR_PTR(-EINTR);
182	else if (!timeout)
183		alg = ERR_PTR(-ETIMEDOUT);
184	else if (!alg)
185		alg = ERR_PTR(-ENOENT);
186	else if (crypto_is_test_larval(larval) &&
187		 !(alg->cra_flags & CRYPTO_ALG_TESTED))
188		alg = ERR_PTR(-EAGAIN);
189	else if (!crypto_mod_get(alg))
190		alg = ERR_PTR(-EAGAIN);
191	crypto_mod_put(&larval->alg);
192
193	return alg;
194}
195
196struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
197{
198	struct crypto_alg *alg;
199
200	down_read(&crypto_alg_sem);
201	alg = __crypto_alg_lookup(name, type, mask);
202	up_read(&crypto_alg_sem);
203
204	return alg;
205}
206EXPORT_SYMBOL_GPL(crypto_alg_lookup);
207
208struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
209{
210	struct crypto_alg *alg;
211
212	if (!name)
213		return ERR_PTR(-ENOENT);
214
215	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
216	type &= mask;
217
218	alg = crypto_alg_lookup(name, type, mask);
219	if (!alg) {
220		request_module("%s", name);
221
222		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
223		      CRYPTO_ALG_NEED_FALLBACK))
224			request_module("%s-all", name);
225
226		alg = crypto_alg_lookup(name, type, mask);
227	}
228
229	if (alg)
230		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
231
232	return crypto_larval_add(name, type, mask);
233}
234EXPORT_SYMBOL_GPL(crypto_larval_lookup);
235
236int crypto_probing_notify(unsigned long val, void *v)
237{
238	int ok;
239
240	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
241	if (ok == NOTIFY_DONE) {
242		request_module("cryptomgr");
243		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
244	}
245
246	return ok;
247}
248EXPORT_SYMBOL_GPL(crypto_probing_notify);
249
250struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
251{
252	struct crypto_alg *alg;
253	struct crypto_alg *larval;
254	int ok;
255
256	if (!((type | mask) & CRYPTO_ALG_TESTED)) {
257		type |= CRYPTO_ALG_TESTED;
258		mask |= CRYPTO_ALG_TESTED;
259	}
260
261	larval = crypto_larval_lookup(name, type, mask);
262	if (IS_ERR(larval) || !crypto_is_larval(larval))
263		return larval;
264
265	ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
266
267	if (ok == NOTIFY_STOP)
268		alg = crypto_larval_wait(larval);
269	else {
270		crypto_mod_put(larval);
271		alg = ERR_PTR(-ENOENT);
272	}
273	crypto_larval_kill(larval);
274	return alg;
275}
276EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
277
278static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
279{
280	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
281
282	if (type_obj)
283		return type_obj->init(tfm, type, mask);
284
285	switch (crypto_tfm_alg_type(tfm)) {
286	case CRYPTO_ALG_TYPE_CIPHER:
287		return crypto_init_cipher_ops(tfm);
288
289	case CRYPTO_ALG_TYPE_COMPRESS:
290		return crypto_init_compress_ops(tfm);
291
292	default:
293		break;
294	}
295
296	BUG();
297	return -EINVAL;
298}
299
300static void crypto_exit_ops(struct crypto_tfm *tfm)
301{
302	const struct crypto_type *type = tfm->__crt_alg->cra_type;
303
304	if (type) {
305		if (tfm->exit)
306			tfm->exit(tfm);
307		return;
308	}
309
310	switch (crypto_tfm_alg_type(tfm)) {
311	case CRYPTO_ALG_TYPE_CIPHER:
312		crypto_exit_cipher_ops(tfm);
313		break;
314
315	case CRYPTO_ALG_TYPE_COMPRESS:
316		crypto_exit_compress_ops(tfm);
317		break;
318
319	default:
320		BUG();
321	}
322}
323
324static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
325{
326	const struct crypto_type *type_obj = alg->cra_type;
327	unsigned int len;
328
329	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
330	if (type_obj)
331		return len + type_obj->ctxsize(alg, type, mask);
332
333	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
334	default:
335		BUG();
336
337	case CRYPTO_ALG_TYPE_CIPHER:
338		len += crypto_cipher_ctxsize(alg);
339		break;
340
341	case CRYPTO_ALG_TYPE_COMPRESS:
342		len += crypto_compress_ctxsize(alg);
343		break;
344	}
345
346	return len;
347}
348
349void crypto_shoot_alg(struct crypto_alg *alg)
350{
351	down_write(&crypto_alg_sem);
352	alg->cra_flags |= CRYPTO_ALG_DYING;
353	up_write(&crypto_alg_sem);
354}
355EXPORT_SYMBOL_GPL(crypto_shoot_alg);
356
357struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
358				      u32 mask)
359{
360	struct crypto_tfm *tfm = NULL;
361	unsigned int tfm_size;
362	int err = -ENOMEM;
363
364	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
365	tfm = kzalloc(tfm_size, GFP_KERNEL);
366	if (tfm == NULL)
367		goto out_err;
368
369	tfm->__crt_alg = alg;
370
371	err = crypto_init_ops(tfm, type, mask);
372	if (err)
373		goto out_free_tfm;
374
375	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
376		goto cra_init_failed;
377
378	goto out;
379
380cra_init_failed:
381	crypto_exit_ops(tfm);
382out_free_tfm:
383	if (err == -EAGAIN)
384		crypto_shoot_alg(alg);
385	kfree(tfm);
386out_err:
387	tfm = ERR_PTR(err);
388out:
389	return tfm;
390}
391EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
392
393/*
394 *	crypto_alloc_base - Locate algorithm and allocate transform
395 *	@alg_name: Name of algorithm
396 *	@type: Type of algorithm
397 *	@mask: Mask for type comparison
398 *
399 *	This function should not be used by new algorithm types.
400 *	Plesae use crypto_alloc_tfm instead.
401 *
402 *	crypto_alloc_base() will first attempt to locate an already loaded
403 *	algorithm.  If that fails and the kernel supports dynamically loadable
404 *	modules, it will then attempt to load a module of the same name or
405 *	alias.  If that fails it will send a query to any loaded crypto manager
406 *	to construct an algorithm on the fly.  A refcount is grabbed on the
407 *	algorithm which is then associated with the new transform.
408 *
409 *	The returned transform is of a non-determinate type.  Most people
410 *	should use one of the more specific allocation functions such as
411 *	crypto_alloc_blkcipher.
412 *
413 *	In case of error the return value is an error pointer.
414 */
415struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
416{
417	struct crypto_tfm *tfm;
418	int err;
419
420	for (;;) {
421		struct crypto_alg *alg;
422
423		alg = crypto_alg_mod_lookup(alg_name, type, mask);
424		if (IS_ERR(alg)) {
425			err = PTR_ERR(alg);
426			goto err;
427		}
428
429		tfm = __crypto_alloc_tfm(alg, type, mask);
430		if (!IS_ERR(tfm))
431			return tfm;
432
433		crypto_mod_put(alg);
434		err = PTR_ERR(tfm);
435
436err:
437		if (err != -EAGAIN)
438			break;
439		if (signal_pending(current)) {
440			err = -EINTR;
441			break;
442		}
443	}
444
445	return ERR_PTR(err);
446}
447EXPORT_SYMBOL_GPL(crypto_alloc_base);
448
449void *crypto_create_tfm(struct crypto_alg *alg,
450			const struct crypto_type *frontend)
451{
452	char *mem;
453	struct crypto_tfm *tfm = NULL;
454	unsigned int tfmsize;
455	unsigned int total;
456	int err = -ENOMEM;
457
458	tfmsize = frontend->tfmsize;
459	total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
460
461	mem = kzalloc(total, GFP_KERNEL);
462	if (mem == NULL)
463		goto out_err;
464
465	tfm = (struct crypto_tfm *)(mem + tfmsize);
466	tfm->__crt_alg = alg;
467
468	err = frontend->init_tfm(tfm);
469	if (err)
470		goto out_free_tfm;
471
472	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
473		goto cra_init_failed;
474
475	goto out;
476
477cra_init_failed:
478	crypto_exit_ops(tfm);
479out_free_tfm:
480	if (err == -EAGAIN)
481		crypto_shoot_alg(alg);
482	kfree(mem);
483out_err:
484	mem = ERR_PTR(err);
485out:
486	return mem;
487}
488EXPORT_SYMBOL_GPL(crypto_create_tfm);
489
490struct crypto_alg *crypto_find_alg(const char *alg_name,
491				   const struct crypto_type *frontend,
492				   u32 type, u32 mask)
493{
494	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
495		crypto_alg_mod_lookup;
496
497	if (frontend) {
498		type &= frontend->maskclear;
499		mask &= frontend->maskclear;
500		type |= frontend->type;
501		mask |= frontend->maskset;
502
503		if (frontend->lookup)
504			lookup = frontend->lookup;
505	}
506
507	return lookup(alg_name, type, mask);
508}
509EXPORT_SYMBOL_GPL(crypto_find_alg);
510
511/*
512 *	crypto_alloc_tfm - Locate algorithm and allocate transform
513 *	@alg_name: Name of algorithm
514 *	@frontend: Frontend algorithm type
515 *	@type: Type of algorithm
516 *	@mask: Mask for type comparison
517 *
518 *	crypto_alloc_tfm() will first attempt to locate an already loaded
519 *	algorithm.  If that fails and the kernel supports dynamically loadable
520 *	modules, it will then attempt to load a module of the same name or
521 *	alias.  If that fails it will send a query to any loaded crypto manager
522 *	to construct an algorithm on the fly.  A refcount is grabbed on the
523 *	algorithm which is then associated with the new transform.
524 *
525 *	The returned transform is of a non-determinate type.  Most people
526 *	should use one of the more specific allocation functions such as
527 *	crypto_alloc_blkcipher.
528 *
529 *	In case of error the return value is an error pointer.
530 */
531void *crypto_alloc_tfm(const char *alg_name,
532		       const struct crypto_type *frontend, u32 type, u32 mask)
533{
534	void *tfm;
535	int err;
536
537	for (;;) {
538		struct crypto_alg *alg;
539
540		alg = crypto_find_alg(alg_name, frontend, type, mask);
541		if (IS_ERR(alg)) {
542			err = PTR_ERR(alg);
543			goto err;
544		}
545
546		tfm = crypto_create_tfm(alg, frontend);
547		if (!IS_ERR(tfm))
548			return tfm;
549
550		crypto_mod_put(alg);
551		err = PTR_ERR(tfm);
552
553err:
554		if (err != -EAGAIN)
555			break;
556		if (signal_pending(current)) {
557			err = -EINTR;
558			break;
559		}
560	}
561
562	return ERR_PTR(err);
563}
564EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
565
566/*
567 *	crypto_destroy_tfm - Free crypto transform
568 *	@mem: Start of tfm slab
569 *	@tfm: Transform to free
570 *
571 *	This function frees up the transform and any associated resources,
572 *	then drops the refcount on the associated algorithm.
573 */
574void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
575{
576	struct crypto_alg *alg;
577
578	if (unlikely(!mem))
579		return;
580
581	alg = tfm->__crt_alg;
582
583	if (!tfm->exit && alg->cra_exit)
584		alg->cra_exit(tfm);
585	crypto_exit_ops(tfm);
586	crypto_mod_put(alg);
587	kzfree(mem);
588}
589EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
590
591int crypto_has_alg(const char *name, u32 type, u32 mask)
592{
593	int ret = 0;
594	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
595
596	if (!IS_ERR(alg)) {
597		crypto_mod_put(alg);
598		ret = 1;
599	}
600
601	return ret;
602}
603EXPORT_SYMBOL_GPL(crypto_has_alg);
604
605MODULE_DESCRIPTION("Cryptographic core API");
606MODULE_LICENSE("GPL");
607