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