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 struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
38
39struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
40{
41	return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
42}
43EXPORT_SYMBOL_GPL(crypto_mod_get);
44
45void crypto_mod_put(struct crypto_alg *alg)
46{
47	struct module *module = alg->cra_module;
48
49	crypto_alg_put(alg);
50	module_put(module);
51}
52EXPORT_SYMBOL_GPL(crypto_mod_put);
53
54static inline int crypto_is_test_larval(struct crypto_larval *larval)
55{
56	return larval->alg.cra_driver_name[0];
57}
58
59static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
60					      u32 mask)
61{
62	struct crypto_alg *q, *alg = NULL;
63	int best = -2;
64
65	list_for_each_entry(q, &crypto_alg_list, cra_list) {
66		int exact, fuzzy;
67
68		if (crypto_is_moribund(q))
69			continue;
70
71		if ((q->cra_flags ^ type) & mask)
72			continue;
73
74		if (crypto_is_larval(q) &&
75		    !crypto_is_test_larval((struct crypto_larval *)q) &&
76		    ((struct crypto_larval *)q)->mask != mask)
77			continue;
78
79		exact = !strcmp(q->cra_driver_name, name);
80		fuzzy = !strcmp(q->cra_name, name);
81		if (!exact && !(fuzzy && q->cra_priority > best))
82			continue;
83
84		if (unlikely(!crypto_mod_get(q)))
85			continue;
86
87		best = q->cra_priority;
88		if (alg)
89			crypto_mod_put(alg);
90		alg = q;
91
92		if (exact)
93			break;
94	}
95
96	return alg;
97}
98
99static void crypto_larval_destroy(struct crypto_alg *alg)
100{
101	struct crypto_larval *larval = (void *)alg;
102
103	BUG_ON(!crypto_is_larval(alg));
104	if (larval->adult)
105		crypto_mod_put(larval->adult);
106	kfree(larval);
107}
108
109struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
110{
111	struct crypto_larval *larval;
112
113	larval = kzalloc(sizeof(*larval), GFP_KERNEL);
114	if (!larval)
115		return ERR_PTR(-ENOMEM);
116
117	larval->mask = mask;
118	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
119	larval->alg.cra_priority = -1;
120	larval->alg.cra_destroy = crypto_larval_destroy;
121
122	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
123	init_completion(&larval->completion);
124
125	return larval;
126}
127EXPORT_SYMBOL_GPL(crypto_larval_alloc);
128
129static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
130					    u32 mask)
131{
132	struct crypto_alg *alg;
133	struct crypto_larval *larval;
134
135	larval = crypto_larval_alloc(name, type, mask);
136	if (IS_ERR(larval))
137		return ERR_CAST(larval);
138
139	atomic_set(&larval->alg.cra_refcnt, 2);
140
141	down_write(&crypto_alg_sem);
142	alg = __crypto_alg_lookup(name, type, mask);
143	if (!alg) {
144		alg = &larval->alg;
145		list_add(&alg->cra_list, &crypto_alg_list);
146	}
147	up_write(&crypto_alg_sem);
148
149	if (alg != &larval->alg) {
150		kfree(larval);
151		if (crypto_is_larval(alg))
152			alg = crypto_larval_wait(alg);
153	}
154
155	return alg;
156}
157
158void crypto_larval_kill(struct crypto_alg *alg)
159{
160	struct crypto_larval *larval = (void *)alg;
161
162	down_write(&crypto_alg_sem);
163	list_del(&alg->cra_list);
164	up_write(&crypto_alg_sem);
165	complete_all(&larval->completion);
166	crypto_alg_put(alg);
167}
168EXPORT_SYMBOL_GPL(crypto_larval_kill);
169
170static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
171{
172	struct crypto_larval *larval = (void *)alg;
173	long timeout;
174
175	timeout = wait_for_completion_killable_timeout(
176		&larval->completion, 60 * HZ);
177
178	alg = larval->adult;
179	if (timeout < 0)
180		alg = ERR_PTR(-EINTR);
181	else if (!timeout)
182		alg = ERR_PTR(-ETIMEDOUT);
183	else if (!alg)
184		alg = ERR_PTR(-ENOENT);
185	else if (crypto_is_test_larval(larval) &&
186		 !(alg->cra_flags & CRYPTO_ALG_TESTED))
187		alg = ERR_PTR(-EAGAIN);
188	else if (!crypto_mod_get(alg))
189		alg = ERR_PTR(-EAGAIN);
190	crypto_mod_put(&larval->alg);
191
192	return alg;
193}
194
195struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
196{
197	struct crypto_alg *alg;
198
199	down_read(&crypto_alg_sem);
200	alg = __crypto_alg_lookup(name, type, mask);
201	up_read(&crypto_alg_sem);
202
203	return alg;
204}
205EXPORT_SYMBOL_GPL(crypto_alg_lookup);
206
207struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
208{
209	struct crypto_alg *alg;
210
211	if (!name)
212		return ERR_PTR(-ENOENT);
213
214	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
215	type &= mask;
216
217	alg = crypto_alg_lookup(name, type, mask);
218	if (!alg) {
219		request_module("crypto-%s", name);
220
221		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
222		      CRYPTO_ALG_NEED_FALLBACK))
223			request_module("crypto-%s-all", name);
224
225		alg = crypto_alg_lookup(name, type, mask);
226	}
227
228	if (alg)
229		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
230
231	return crypto_larval_add(name, type, mask);
232}
233EXPORT_SYMBOL_GPL(crypto_larval_lookup);
234
235int crypto_probing_notify(unsigned long val, void *v)
236{
237	int ok;
238
239	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
240	if (ok == NOTIFY_DONE) {
241		request_module("cryptomgr");
242		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
243	}
244
245	return ok;
246}
247EXPORT_SYMBOL_GPL(crypto_probing_notify);
248
249struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
250{
251	struct crypto_alg *alg;
252	struct crypto_alg *larval;
253	int ok;
254
255	if (!((type | mask) & CRYPTO_ALG_TESTED)) {
256		type |= CRYPTO_ALG_TESTED;
257		mask |= CRYPTO_ALG_TESTED;
258	}
259
260	/*
261	 * If the internal flag is set for a cipher, require a caller to
262	 * to invoke the cipher with the internal flag to use that cipher.
263	 * Also, if a caller wants to allocate a cipher that may or may
264	 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
265	 * !(mask & CRYPTO_ALG_INTERNAL).
266	 */
267	if (!((type | mask) & CRYPTO_ALG_INTERNAL))
268		mask |= CRYPTO_ALG_INTERNAL;
269
270	larval = crypto_larval_lookup(name, type, mask);
271	if (IS_ERR(larval) || !crypto_is_larval(larval))
272		return larval;
273
274	ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
275
276	if (ok == NOTIFY_STOP)
277		alg = crypto_larval_wait(larval);
278	else {
279		crypto_mod_put(larval);
280		alg = ERR_PTR(-ENOENT);
281	}
282	crypto_larval_kill(larval);
283	return alg;
284}
285EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
286
287static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
288{
289	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
290
291	if (type_obj)
292		return type_obj->init(tfm, type, mask);
293
294	switch (crypto_tfm_alg_type(tfm)) {
295	case CRYPTO_ALG_TYPE_CIPHER:
296		return crypto_init_cipher_ops(tfm);
297
298	case CRYPTO_ALG_TYPE_COMPRESS:
299		return crypto_init_compress_ops(tfm);
300
301	default:
302		break;
303	}
304
305	BUG();
306	return -EINVAL;
307}
308
309static void crypto_exit_ops(struct crypto_tfm *tfm)
310{
311	const struct crypto_type *type = tfm->__crt_alg->cra_type;
312
313	if (type) {
314		if (tfm->exit)
315			tfm->exit(tfm);
316		return;
317	}
318
319	switch (crypto_tfm_alg_type(tfm)) {
320	case CRYPTO_ALG_TYPE_CIPHER:
321		crypto_exit_cipher_ops(tfm);
322		break;
323
324	case CRYPTO_ALG_TYPE_COMPRESS:
325		crypto_exit_compress_ops(tfm);
326		break;
327
328	default:
329		BUG();
330	}
331}
332
333static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
334{
335	const struct crypto_type *type_obj = alg->cra_type;
336	unsigned int len;
337
338	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
339	if (type_obj)
340		return len + type_obj->ctxsize(alg, type, mask);
341
342	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
343	default:
344		BUG();
345
346	case CRYPTO_ALG_TYPE_CIPHER:
347		len += crypto_cipher_ctxsize(alg);
348		break;
349
350	case CRYPTO_ALG_TYPE_COMPRESS:
351		len += crypto_compress_ctxsize(alg);
352		break;
353	}
354
355	return len;
356}
357
358void crypto_shoot_alg(struct crypto_alg *alg)
359{
360	down_write(&crypto_alg_sem);
361	alg->cra_flags |= CRYPTO_ALG_DYING;
362	up_write(&crypto_alg_sem);
363}
364EXPORT_SYMBOL_GPL(crypto_shoot_alg);
365
366struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
367				      u32 mask)
368{
369	struct crypto_tfm *tfm = NULL;
370	unsigned int tfm_size;
371	int err = -ENOMEM;
372
373	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
374	tfm = kzalloc(tfm_size, GFP_KERNEL);
375	if (tfm == NULL)
376		goto out_err;
377
378	tfm->__crt_alg = alg;
379
380	err = crypto_init_ops(tfm, type, mask);
381	if (err)
382		goto out_free_tfm;
383
384	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
385		goto cra_init_failed;
386
387	goto out;
388
389cra_init_failed:
390	crypto_exit_ops(tfm);
391out_free_tfm:
392	if (err == -EAGAIN)
393		crypto_shoot_alg(alg);
394	kfree(tfm);
395out_err:
396	tfm = ERR_PTR(err);
397out:
398	return tfm;
399}
400EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
401
402/*
403 *	crypto_alloc_base - Locate algorithm and allocate transform
404 *	@alg_name: Name of algorithm
405 *	@type: Type of algorithm
406 *	@mask: Mask for type comparison
407 *
408 *	This function should not be used by new algorithm types.
409 *	Please use crypto_alloc_tfm instead.
410 *
411 *	crypto_alloc_base() will first attempt to locate an already loaded
412 *	algorithm.  If that fails and the kernel supports dynamically loadable
413 *	modules, it will then attempt to load a module of the same name or
414 *	alias.  If that fails it will send a query to any loaded crypto manager
415 *	to construct an algorithm on the fly.  A refcount is grabbed on the
416 *	algorithm which is then associated with the new transform.
417 *
418 *	The returned transform is of a non-determinate type.  Most people
419 *	should use one of the more specific allocation functions such as
420 *	crypto_alloc_blkcipher.
421 *
422 *	In case of error the return value is an error pointer.
423 */
424struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
425{
426	struct crypto_tfm *tfm;
427	int err;
428
429	for (;;) {
430		struct crypto_alg *alg;
431
432		alg = crypto_alg_mod_lookup(alg_name, type, mask);
433		if (IS_ERR(alg)) {
434			err = PTR_ERR(alg);
435			goto err;
436		}
437
438		tfm = __crypto_alloc_tfm(alg, type, mask);
439		if (!IS_ERR(tfm))
440			return tfm;
441
442		crypto_mod_put(alg);
443		err = PTR_ERR(tfm);
444
445err:
446		if (err != -EAGAIN)
447			break;
448		if (fatal_signal_pending(current)) {
449			err = -EINTR;
450			break;
451		}
452	}
453
454	return ERR_PTR(err);
455}
456EXPORT_SYMBOL_GPL(crypto_alloc_base);
457
458void *crypto_create_tfm(struct crypto_alg *alg,
459			const struct crypto_type *frontend)
460{
461	char *mem;
462	struct crypto_tfm *tfm = NULL;
463	unsigned int tfmsize;
464	unsigned int total;
465	int err = -ENOMEM;
466
467	tfmsize = frontend->tfmsize;
468	total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
469
470	mem = kzalloc(total, GFP_KERNEL);
471	if (mem == NULL)
472		goto out_err;
473
474	tfm = (struct crypto_tfm *)(mem + tfmsize);
475	tfm->__crt_alg = alg;
476
477	err = frontend->init_tfm(tfm);
478	if (err)
479		goto out_free_tfm;
480
481	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
482		goto cra_init_failed;
483
484	goto out;
485
486cra_init_failed:
487	crypto_exit_ops(tfm);
488out_free_tfm:
489	if (err == -EAGAIN)
490		crypto_shoot_alg(alg);
491	kfree(mem);
492out_err:
493	mem = ERR_PTR(err);
494out:
495	return mem;
496}
497EXPORT_SYMBOL_GPL(crypto_create_tfm);
498
499struct crypto_alg *crypto_find_alg(const char *alg_name,
500				   const struct crypto_type *frontend,
501				   u32 type, u32 mask)
502{
503	struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
504		crypto_alg_mod_lookup;
505
506	if (frontend) {
507		type &= frontend->maskclear;
508		mask &= frontend->maskclear;
509		type |= frontend->type;
510		mask |= frontend->maskset;
511
512		if (frontend->lookup)
513			lookup = frontend->lookup;
514	}
515
516	return lookup(alg_name, type, mask);
517}
518EXPORT_SYMBOL_GPL(crypto_find_alg);
519
520/*
521 *	crypto_alloc_tfm - Locate algorithm and allocate transform
522 *	@alg_name: Name of algorithm
523 *	@frontend: Frontend algorithm type
524 *	@type: Type of algorithm
525 *	@mask: Mask for type comparison
526 *
527 *	crypto_alloc_tfm() will first attempt to locate an already loaded
528 *	algorithm.  If that fails and the kernel supports dynamically loadable
529 *	modules, it will then attempt to load a module of the same name or
530 *	alias.  If that fails it will send a query to any loaded crypto manager
531 *	to construct an algorithm on the fly.  A refcount is grabbed on the
532 *	algorithm which is then associated with the new transform.
533 *
534 *	The returned transform is of a non-determinate type.  Most people
535 *	should use one of the more specific allocation functions such as
536 *	crypto_alloc_blkcipher.
537 *
538 *	In case of error the return value is an error pointer.
539 */
540void *crypto_alloc_tfm(const char *alg_name,
541		       const struct crypto_type *frontend, u32 type, u32 mask)
542{
543	void *tfm;
544	int err;
545
546	for (;;) {
547		struct crypto_alg *alg;
548
549		alg = crypto_find_alg(alg_name, frontend, type, mask);
550		if (IS_ERR(alg)) {
551			err = PTR_ERR(alg);
552			goto err;
553		}
554
555		tfm = crypto_create_tfm(alg, frontend);
556		if (!IS_ERR(tfm))
557			return tfm;
558
559		crypto_mod_put(alg);
560		err = PTR_ERR(tfm);
561
562err:
563		if (err != -EAGAIN)
564			break;
565		if (fatal_signal_pending(current)) {
566			err = -EINTR;
567			break;
568		}
569	}
570
571	return ERR_PTR(err);
572}
573EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
574
575/*
576 *	crypto_destroy_tfm - Free crypto transform
577 *	@mem: Start of tfm slab
578 *	@tfm: Transform to free
579 *
580 *	This function frees up the transform and any associated resources,
581 *	then drops the refcount on the associated algorithm.
582 */
583void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
584{
585	struct crypto_alg *alg;
586
587	if (unlikely(!mem))
588		return;
589
590	alg = tfm->__crt_alg;
591
592	if (!tfm->exit && alg->cra_exit)
593		alg->cra_exit(tfm);
594	crypto_exit_ops(tfm);
595	crypto_mod_put(alg);
596	kzfree(mem);
597}
598EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
599
600int crypto_has_alg(const char *name, u32 type, u32 mask)
601{
602	int ret = 0;
603	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
604
605	if (!IS_ERR(alg)) {
606		crypto_mod_put(alg);
607		ret = 1;
608	}
609
610	return ret;
611}
612EXPORT_SYMBOL_GPL(crypto_has_alg);
613
614MODULE_DESCRIPTION("Cryptographic core API");
615MODULE_LICENSE("GPL");
616