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
58struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, 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		    ((struct crypto_larval *)q)->mask != mask)
74			continue;
75
76		exact = !strcmp(q->cra_driver_name, name);
77		fuzzy = !strcmp(q->cra_name, name);
78		if (!exact && !(fuzzy && q->cra_priority > best))
79			continue;
80
81		if (unlikely(!crypto_mod_get(q)))
82			continue;
83
84		best = q->cra_priority;
85		if (alg)
86			crypto_mod_put(alg);
87		alg = q;
88
89		if (exact)
90			break;
91	}
92
93	return alg;
94}
95EXPORT_SYMBOL_GPL(__crypto_alg_lookup);
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
107static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type,
108					      u32 mask)
109{
110	struct crypto_alg *alg;
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	atomic_set(&larval->alg.cra_refcnt, 2);
123	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
124	init_completion(&larval->completion);
125
126	down_write(&crypto_alg_sem);
127	alg = __crypto_alg_lookup(name, type, mask);
128	if (!alg) {
129		alg = &larval->alg;
130		list_add(&alg->cra_list, &crypto_alg_list);
131	}
132	up_write(&crypto_alg_sem);
133
134	if (alg != &larval->alg)
135		kfree(larval);
136
137	return alg;
138}
139
140static void crypto_larval_kill(struct crypto_alg *alg)
141{
142	struct crypto_larval *larval = (void *)alg;
143
144	down_write(&crypto_alg_sem);
145	list_del(&alg->cra_list);
146	up_write(&crypto_alg_sem);
147	complete(&larval->completion);
148	crypto_alg_put(alg);
149}
150
151static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
152{
153	struct crypto_larval *larval = (void *)alg;
154
155	wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
156	alg = larval->adult;
157	if (alg) {
158		if (!crypto_mod_get(alg))
159			alg = ERR_PTR(-EAGAIN);
160	} else
161		alg = ERR_PTR(-ENOENT);
162	crypto_mod_put(&larval->alg);
163
164	return alg;
165}
166
167static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
168					    u32 mask)
169{
170	struct crypto_alg *alg;
171
172	down_read(&crypto_alg_sem);
173	alg = __crypto_alg_lookup(name, type, mask);
174	up_read(&crypto_alg_sem);
175
176	return alg;
177}
178
179struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
180{
181	struct crypto_alg *alg;
182	struct crypto_alg *larval;
183	int ok;
184
185	if (!name)
186		return ERR_PTR(-ENOENT);
187
188	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
189	type &= mask;
190
191	alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
192				      name);
193	if (alg)
194		return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
195
196	larval = crypto_larval_alloc(name, type, mask);
197	if (IS_ERR(larval) || !crypto_is_larval(larval))
198		return larval;
199
200	ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
201	if (ok == NOTIFY_DONE) {
202		request_module("cryptomgr");
203		ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
204	}
205
206	if (ok == NOTIFY_STOP)
207		alg = crypto_larval_wait(larval);
208	else {
209		crypto_mod_put(larval);
210		alg = ERR_PTR(-ENOENT);
211	}
212	crypto_larval_kill(larval);
213	return alg;
214}
215EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
216
217static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
218{
219	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
220
221	if (type_obj)
222		return type_obj->init(tfm, type, mask);
223
224	switch (crypto_tfm_alg_type(tfm)) {
225	case CRYPTO_ALG_TYPE_CIPHER:
226		return crypto_init_cipher_ops(tfm);
227
228	case CRYPTO_ALG_TYPE_DIGEST:
229		return crypto_init_digest_ops(tfm);
230
231	case CRYPTO_ALG_TYPE_COMPRESS:
232		return crypto_init_compress_ops(tfm);
233
234	default:
235		break;
236	}
237
238	BUG();
239	return -EINVAL;
240}
241
242static void crypto_exit_ops(struct crypto_tfm *tfm)
243{
244	const struct crypto_type *type = tfm->__crt_alg->cra_type;
245
246	if (type) {
247		if (type->exit)
248			type->exit(tfm);
249		return;
250	}
251
252	switch (crypto_tfm_alg_type(tfm)) {
253	case CRYPTO_ALG_TYPE_CIPHER:
254		crypto_exit_cipher_ops(tfm);
255		break;
256
257	case CRYPTO_ALG_TYPE_DIGEST:
258		crypto_exit_digest_ops(tfm);
259		break;
260
261	case CRYPTO_ALG_TYPE_COMPRESS:
262		crypto_exit_compress_ops(tfm);
263		break;
264
265	default:
266		BUG();
267
268	}
269}
270
271static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
272{
273	const struct crypto_type *type_obj = alg->cra_type;
274	unsigned int len;
275
276	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
277	if (type_obj)
278		return len + type_obj->ctxsize(alg, type, mask);
279
280	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
281	default:
282		BUG();
283
284	case CRYPTO_ALG_TYPE_CIPHER:
285		len += crypto_cipher_ctxsize(alg);
286		break;
287
288	case CRYPTO_ALG_TYPE_DIGEST:
289		len += crypto_digest_ctxsize(alg);
290		break;
291
292	case CRYPTO_ALG_TYPE_COMPRESS:
293		len += crypto_compress_ctxsize(alg);
294		break;
295	}
296
297	return len;
298}
299
300void crypto_shoot_alg(struct crypto_alg *alg)
301{
302	down_write(&crypto_alg_sem);
303	alg->cra_flags |= CRYPTO_ALG_DYING;
304	up_write(&crypto_alg_sem);
305}
306EXPORT_SYMBOL_GPL(crypto_shoot_alg);
307
308struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
309				      u32 mask)
310{
311	struct crypto_tfm *tfm = NULL;
312	unsigned int tfm_size;
313	int err = -ENOMEM;
314
315	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
316	tfm = kzalloc(tfm_size, GFP_KERNEL);
317	if (tfm == NULL)
318		goto out_err;
319
320	tfm->__crt_alg = alg;
321
322	err = crypto_init_ops(tfm, type, mask);
323	if (err)
324		goto out_free_tfm;
325
326	if (alg->cra_init && (err = alg->cra_init(tfm))) {
327		if (err == -EAGAIN)
328			crypto_shoot_alg(alg);
329		goto cra_init_failed;
330	}
331
332	goto out;
333
334cra_init_failed:
335	crypto_exit_ops(tfm);
336out_free_tfm:
337	kfree(tfm);
338out_err:
339	tfm = ERR_PTR(err);
340out:
341	return tfm;
342}
343EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
344
345/*
346 *	crypto_alloc_base - Locate algorithm and allocate transform
347 *	@alg_name: Name of algorithm
348 *	@type: Type of algorithm
349 *	@mask: Mask for type comparison
350 *
351 *	crypto_alloc_base() will first attempt to locate an already loaded
352 *	algorithm.  If that fails and the kernel supports dynamically loadable
353 *	modules, it will then attempt to load a module of the same name or
354 *	alias.  If that fails it will send a query to any loaded crypto manager
355 *	to construct an algorithm on the fly.  A refcount is grabbed on the
356 *	algorithm which is then associated with the new transform.
357 *
358 *	The returned transform is of a non-determinate type.  Most people
359 *	should use one of the more specific allocation functions such as
360 *	crypto_alloc_blkcipher.
361 *
362 *	In case of error the return value is an error pointer.
363 */
364struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
365{
366	struct crypto_tfm *tfm;
367	int err;
368
369	for (;;) {
370		struct crypto_alg *alg;
371
372		alg = crypto_alg_mod_lookup(alg_name, type, mask);
373		if (IS_ERR(alg)) {
374			err = PTR_ERR(alg);
375			goto err;
376		}
377
378		tfm = __crypto_alloc_tfm(alg, type, mask);
379		if (!IS_ERR(tfm))
380			return tfm;
381
382		crypto_mod_put(alg);
383		err = PTR_ERR(tfm);
384
385err:
386		if (err != -EAGAIN)
387			break;
388		if (signal_pending(current)) {
389			err = -EINTR;
390			break;
391		}
392	}
393
394	return ERR_PTR(err);
395}
396EXPORT_SYMBOL_GPL(crypto_alloc_base);
397
398/*
399 *	crypto_free_tfm - Free crypto transform
400 *	@tfm: Transform to free
401 *
402 *	crypto_free_tfm() frees up the transform and any associated resources,
403 *	then drops the refcount on the associated algorithm.
404 */
405void crypto_free_tfm(struct crypto_tfm *tfm)
406{
407	struct crypto_alg *alg;
408	int size;
409
410	if (unlikely(!tfm))
411		return;
412
413	alg = tfm->__crt_alg;
414	size = sizeof(*tfm) + alg->cra_ctxsize;
415
416	if (alg->cra_exit)
417		alg->cra_exit(tfm);
418	crypto_exit_ops(tfm);
419	crypto_mod_put(alg);
420	memset(tfm, 0, size);
421	kfree(tfm);
422}
423
424EXPORT_SYMBOL_GPL(crypto_free_tfm);
425
426int crypto_has_alg(const char *name, u32 type, u32 mask)
427{
428	int ret = 0;
429	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
430
431	if (!IS_ERR(alg)) {
432		crypto_mod_put(alg);
433		ret = 1;
434	}
435
436	return ret;
437}
438EXPORT_SYMBOL_GPL(crypto_has_alg);
439