[CRYPTO] api: Allow multiple frontends per backend
[linux-2.6.git] / crypto / algapi.c
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_spawns(struct list_head *spawns,
88                                  struct list_head *list)
89 {
90         struct crypto_spawn *spawn, *n;
91
92         list_for_each_entry_safe(spawn, n, spawns, list) {
93                 struct crypto_instance *inst = spawn->inst;
94                 struct crypto_template *tmpl = inst->tmpl;
95
96                 list_del_init(&spawn->list);
97                 spawn->alg = NULL;
98
99                 if (crypto_is_dead(&inst->alg))
100                         continue;
101
102                 inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
103                 if (!tmpl || !crypto_tmpl_get(tmpl))
104                         continue;
105
106                 crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
107                 list_move(&inst->alg.cra_list, list);
108                 hlist_del(&inst->list);
109                 inst->alg.cra_destroy = crypto_destroy_instance;
110
111                 if (!list_empty(&inst->alg.cra_users)) {
112                         if (&n->list == spawns)
113                                 n = list_entry(inst->alg.cra_users.next,
114                                                typeof(*n), list);
115                         __list_splice(&inst->alg.cra_users, spawns->prev);
116                 }
117         }
118 }
119
120 static int __crypto_register_alg(struct crypto_alg *alg,
121                                  struct list_head *list)
122 {
123         struct crypto_alg *q;
124         int ret = -EAGAIN;
125
126         if (crypto_is_dead(alg))
127                 goto out;
128
129         INIT_LIST_HEAD(&alg->cra_users);
130
131         ret = -EEXIST;
132
133         atomic_set(&alg->cra_refcnt, 1);
134         list_for_each_entry(q, &crypto_alg_list, cra_list) {
135                 if (q == alg)
136                         goto out;
137
138                 if (crypto_is_moribund(q))
139                         continue;
140
141                 if (crypto_is_larval(q)) {
142                         struct crypto_larval *larval = (void *)q;
143
144                         if (strcmp(alg->cra_name, q->cra_name) &&
145                             strcmp(alg->cra_driver_name, q->cra_name))
146                                 continue;
147
148                         if (larval->adult)
149                                 continue;
150                         if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
151                                 continue;
152                         if (!crypto_mod_get(alg))
153                                 continue;
154
155                         larval->adult = alg;
156                         complete(&larval->completion);
157                         continue;
158                 }
159
160                 if (strcmp(alg->cra_name, q->cra_name))
161                         continue;
162
163                 if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
164                     q->cra_priority > alg->cra_priority)
165                         continue;
166
167                 crypto_remove_spawns(&q->cra_users, list);
168         }
169         
170         list_add(&alg->cra_list, &crypto_alg_list);
171
172         crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
173         ret = 0;
174
175 out:    
176         return ret;
177 }
178
179 static void crypto_remove_final(struct list_head *list)
180 {
181         struct crypto_alg *alg;
182         struct crypto_alg *n;
183
184         list_for_each_entry_safe(alg, n, list, cra_list) {
185                 list_del_init(&alg->cra_list);
186                 crypto_alg_put(alg);
187         }
188 }
189
190 int crypto_register_alg(struct crypto_alg *alg)
191 {
192         LIST_HEAD(list);
193         int err;
194
195         err = crypto_check_alg(alg);
196         if (err)
197                 return err;
198
199         down_write(&crypto_alg_sem);
200         err = __crypto_register_alg(alg, &list);
201         up_write(&crypto_alg_sem);
202
203         crypto_remove_final(&list);
204         return err;
205 }
206 EXPORT_SYMBOL_GPL(crypto_register_alg);
207
208 static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
209 {
210         if (unlikely(list_empty(&alg->cra_list)))
211                 return -ENOENT;
212
213         alg->cra_flags |= CRYPTO_ALG_DEAD;
214
215         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
216         list_del_init(&alg->cra_list);
217         crypto_remove_spawns(&alg->cra_users, list);
218
219         return 0;
220 }
221
222 int crypto_unregister_alg(struct crypto_alg *alg)
223 {
224         int ret;
225         LIST_HEAD(list);
226         
227         down_write(&crypto_alg_sem);
228         ret = crypto_remove_alg(alg, &list);
229         up_write(&crypto_alg_sem);
230
231         if (ret)
232                 return ret;
233
234         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
235         if (alg->cra_destroy)
236                 alg->cra_destroy(alg);
237
238         crypto_remove_final(&list);
239         return 0;
240 }
241 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
242
243 int crypto_register_template(struct crypto_template *tmpl)
244 {
245         struct crypto_template *q;
246         int err = -EEXIST;
247
248         down_write(&crypto_alg_sem);
249
250         list_for_each_entry(q, &crypto_template_list, list) {
251                 if (q == tmpl)
252                         goto out;
253         }
254
255         list_add(&tmpl->list, &crypto_template_list);
256         crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
257         err = 0;
258 out:
259         up_write(&crypto_alg_sem);
260         return err;
261 }
262 EXPORT_SYMBOL_GPL(crypto_register_template);
263
264 void crypto_unregister_template(struct crypto_template *tmpl)
265 {
266         struct crypto_instance *inst;
267         struct hlist_node *p, *n;
268         struct hlist_head *list;
269         LIST_HEAD(users);
270
271         down_write(&crypto_alg_sem);
272
273         BUG_ON(list_empty(&tmpl->list));
274         list_del_init(&tmpl->list);
275
276         list = &tmpl->instances;
277         hlist_for_each_entry(inst, p, list, list) {
278                 int err = crypto_remove_alg(&inst->alg, &users);
279                 BUG_ON(err);
280         }
281
282         crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
283
284         up_write(&crypto_alg_sem);
285
286         hlist_for_each_entry_safe(inst, p, n, list, list) {
287                 BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
288                 tmpl->free(inst);
289         }
290         crypto_remove_final(&users);
291 }
292 EXPORT_SYMBOL_GPL(crypto_unregister_template);
293
294 static struct crypto_template *__crypto_lookup_template(const char *name)
295 {
296         struct crypto_template *q, *tmpl = NULL;
297
298         down_read(&crypto_alg_sem);
299         list_for_each_entry(q, &crypto_template_list, list) {
300                 if (strcmp(q->name, name))
301                         continue;
302                 if (unlikely(!crypto_tmpl_get(q)))
303                         continue;
304
305                 tmpl = q;
306                 break;
307         }
308         up_read(&crypto_alg_sem);
309
310         return tmpl;
311 }
312
313 struct crypto_template *crypto_lookup_template(const char *name)
314 {
315         return try_then_request_module(__crypto_lookup_template(name), name);
316 }
317 EXPORT_SYMBOL_GPL(crypto_lookup_template);
318
319 int crypto_register_instance(struct crypto_template *tmpl,
320                              struct crypto_instance *inst)
321 {
322         LIST_HEAD(list);
323         int err = -EINVAL;
324
325         if (inst->alg.cra_destroy)
326                 goto err;
327
328         err = crypto_check_alg(&inst->alg);
329         if (err)
330                 goto err;
331
332         inst->alg.cra_module = tmpl->module;
333
334         down_write(&crypto_alg_sem);
335
336         err = __crypto_register_alg(&inst->alg, &list);
337         if (err)
338                 goto unlock;
339
340         hlist_add_head(&inst->list, &tmpl->instances);
341         inst->tmpl = tmpl;
342
343 unlock:
344         up_write(&crypto_alg_sem);
345
346         crypto_remove_final(&list);
347
348 err:
349         return err;
350 }
351 EXPORT_SYMBOL_GPL(crypto_register_instance);
352
353 int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
354                       struct crypto_instance *inst)
355 {
356         int err = -EAGAIN;
357
358         spawn->inst = inst;
359
360         down_write(&crypto_alg_sem);
361         if (!crypto_is_moribund(alg)) {
362                 list_add(&spawn->list, &alg->cra_users);
363                 spawn->alg = alg;
364                 err = 0;
365         }
366         up_write(&crypto_alg_sem);
367
368         return err;
369 }
370 EXPORT_SYMBOL_GPL(crypto_init_spawn);
371
372 void crypto_drop_spawn(struct crypto_spawn *spawn)
373 {
374         down_write(&crypto_alg_sem);
375         list_del(&spawn->list);
376         up_write(&crypto_alg_sem);
377 }
378 EXPORT_SYMBOL_GPL(crypto_drop_spawn);
379
380 struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,
381                                     u32 mask)
382 {
383         struct crypto_alg *alg;
384         struct crypto_alg *alg2;
385         struct crypto_tfm *tfm;
386
387         down_read(&crypto_alg_sem);
388         alg = spawn->alg;
389         alg2 = alg;
390         if (alg2)
391                 alg2 = crypto_mod_get(alg2);
392         up_read(&crypto_alg_sem);
393
394         if (!alg2) {
395                 if (alg)
396                         crypto_shoot_alg(alg);
397                 return ERR_PTR(-EAGAIN);
398         }
399
400         tfm = ERR_PTR(-EINVAL);
401         if (unlikely((alg->cra_flags ^ type) & mask))
402                 goto out_put_alg;
403
404         tfm = __crypto_alloc_tfm(alg, type, mask);
405         if (IS_ERR(tfm))
406                 goto out_put_alg;
407
408         return tfm;
409
410 out_put_alg:
411         crypto_mod_put(alg);
412         return tfm;
413 }
414 EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
415
416 int crypto_register_notifier(struct notifier_block *nb)
417 {
418         return blocking_notifier_chain_register(&crypto_chain, nb);
419 }
420 EXPORT_SYMBOL_GPL(crypto_register_notifier);
421
422 int crypto_unregister_notifier(struct notifier_block *nb)
423 {
424         return blocking_notifier_chain_unregister(&crypto_chain, nb);
425 }
426 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
427
428 struct crypto_alg *crypto_get_attr_alg(void *param, unsigned int len,
429                                        u32 type, u32 mask)
430 {
431         struct rtattr *rta = param;
432         struct crypto_attr_alg *alga;
433
434         if (!RTA_OK(rta, len))
435                 return ERR_PTR(-EBADR);
436         if (rta->rta_type != CRYPTOA_ALG || RTA_PAYLOAD(rta) < sizeof(*alga))
437                 return ERR_PTR(-EINVAL);
438
439         alga = RTA_DATA(rta);
440         alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;
441
442         return crypto_alg_mod_lookup(alga->name, type, mask);
443 }
444 EXPORT_SYMBOL_GPL(crypto_get_attr_alg);
445
446 struct crypto_instance *crypto_alloc_instance(const char *name,
447                                               struct crypto_alg *alg)
448 {
449         struct crypto_instance *inst;
450         struct crypto_spawn *spawn;
451         int err;
452
453         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
454         if (!inst)
455                 return ERR_PTR(-ENOMEM);
456
457         err = -ENAMETOOLONG;
458         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", name,
459                      alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
460                 goto err_free_inst;
461
462         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
463                      name, alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
464                 goto err_free_inst;
465
466         spawn = crypto_instance_ctx(inst);
467         err = crypto_init_spawn(spawn, alg, inst);
468
469         if (err)
470                 goto err_free_inst;
471
472         return inst;
473
474 err_free_inst:
475         kfree(inst);
476         return ERR_PTR(err);
477 }
478 EXPORT_SYMBOL_GPL(crypto_alloc_instance);
479
480 static int __init crypto_algapi_init(void)
481 {
482         crypto_init_proc();
483         return 0;
484 }
485
486 static void __exit crypto_algapi_exit(void)
487 {
488         crypto_exit_proc();
489 }
490
491 module_init(crypto_algapi_init);
492 module_exit(crypto_algapi_exit);
493
494 MODULE_LICENSE("GPL");
495 MODULE_DESCRIPTION("Cryptographic algorithms API");