[CRYPTO] api: Explain the comparison on larval cra_name
[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_all(&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_blocksize > PAGE_SIZE / 8)
67                 return -EINVAL;
68
69         if (alg->cra_priority < 0)
70                 return -EINVAL;
71
72         return crypto_set_driver_name(alg);
73 }
74
75 static void crypto_destroy_instance(struct crypto_alg *alg)
76 {
77         struct crypto_instance *inst = (void *)alg;
78         struct crypto_template *tmpl = inst->tmpl;
79
80         tmpl->free(inst);
81         crypto_tmpl_put(tmpl);
82 }
83
84 static void crypto_remove_spawn(struct crypto_spawn *spawn,
85                                 struct list_head *list,
86                                 struct list_head *secondary_spawns)
87 {
88         struct crypto_instance *inst = spawn->inst;
89         struct crypto_template *tmpl = inst->tmpl;
90
91         list_del_init(&spawn->list);
92         spawn->alg = NULL;
93
94         if (crypto_is_dead(&inst->alg))
95                 return;
96
97         inst->alg.cra_flags |= CRYPTO_ALG_DEAD;
98         if (!tmpl || !crypto_tmpl_get(tmpl))
99                 return;
100
101         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
102         list_move(&inst->alg.cra_list, list);
103         hlist_del(&inst->list);
104         inst->alg.cra_destroy = crypto_destroy_instance;
105
106         list_splice(&inst->alg.cra_users, secondary_spawns);
107 }
108
109 static void crypto_remove_spawns(struct list_head *spawns,
110                                  struct list_head *list, u32 new_type)
111 {
112         struct crypto_spawn *spawn, *n;
113         LIST_HEAD(secondary_spawns);
114
115         list_for_each_entry_safe(spawn, n, spawns, list) {
116                 if ((spawn->alg->cra_flags ^ new_type) & spawn->mask)
117                         continue;
118
119                 crypto_remove_spawn(spawn, list, &secondary_spawns);
120         }
121
122         while (!list_empty(&secondary_spawns)) {
123                 list_for_each_entry_safe(spawn, n, &secondary_spawns, list)
124                         crypto_remove_spawn(spawn, list, &secondary_spawns);
125         }
126 }
127
128 static int __crypto_register_alg(struct crypto_alg *alg,
129                                  struct list_head *list)
130 {
131         struct crypto_alg *q;
132         int ret = -EAGAIN;
133
134         if (crypto_is_dead(alg))
135                 goto out;
136
137         INIT_LIST_HEAD(&alg->cra_users);
138
139         ret = -EEXIST;
140
141         atomic_set(&alg->cra_refcnt, 1);
142         list_for_each_entry(q, &crypto_alg_list, cra_list) {
143                 if (q == alg)
144                         goto out;
145
146                 if (crypto_is_moribund(q))
147                         continue;
148
149                 if (crypto_is_larval(q)) {
150                         struct crypto_larval *larval = (void *)q;
151
152                         /*
153                          * Check to see if either our generic name or
154                          * specific name can satisfy the name requested
155                          * by the larval entry q.
156                          */
157                         if (strcmp(alg->cra_name, q->cra_name) &&
158                             strcmp(alg->cra_driver_name, q->cra_name))
159                                 continue;
160
161                         if (larval->adult)
162                                 continue;
163                         if ((q->cra_flags ^ alg->cra_flags) & larval->mask)
164                                 continue;
165                         if (!crypto_mod_get(alg))
166                                 continue;
167
168                         larval->adult = alg;
169                         complete_all(&larval->completion);
170                         continue;
171                 }
172
173                 if (strcmp(alg->cra_name, q->cra_name))
174                         continue;
175
176                 if (strcmp(alg->cra_driver_name, q->cra_driver_name) &&
177                     q->cra_priority > alg->cra_priority)
178                         continue;
179
180                 crypto_remove_spawns(&q->cra_users, list, alg->cra_flags);
181         }
182         
183         list_add(&alg->cra_list, &crypto_alg_list);
184
185         crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
186         ret = 0;
187
188 out:    
189         return ret;
190 }
191
192 static void crypto_remove_final(struct list_head *list)
193 {
194         struct crypto_alg *alg;
195         struct crypto_alg *n;
196
197         list_for_each_entry_safe(alg, n, list, cra_list) {
198                 list_del_init(&alg->cra_list);
199                 crypto_alg_put(alg);
200         }
201 }
202
203 int crypto_register_alg(struct crypto_alg *alg)
204 {
205         LIST_HEAD(list);
206         int err;
207
208         err = crypto_check_alg(alg);
209         if (err)
210                 return err;
211
212         down_write(&crypto_alg_sem);
213         err = __crypto_register_alg(alg, &list);
214         up_write(&crypto_alg_sem);
215
216         crypto_remove_final(&list);
217         return err;
218 }
219 EXPORT_SYMBOL_GPL(crypto_register_alg);
220
221 static int crypto_remove_alg(struct crypto_alg *alg, struct list_head *list)
222 {
223         if (unlikely(list_empty(&alg->cra_list)))
224                 return -ENOENT;
225
226         alg->cra_flags |= CRYPTO_ALG_DEAD;
227
228         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
229         list_del_init(&alg->cra_list);
230         crypto_remove_spawns(&alg->cra_users, list, alg->cra_flags);
231
232         return 0;
233 }
234
235 int crypto_unregister_alg(struct crypto_alg *alg)
236 {
237         int ret;
238         LIST_HEAD(list);
239         
240         down_write(&crypto_alg_sem);
241         ret = crypto_remove_alg(alg, &list);
242         up_write(&crypto_alg_sem);
243
244         if (ret)
245                 return ret;
246
247         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
248         if (alg->cra_destroy)
249                 alg->cra_destroy(alg);
250
251         crypto_remove_final(&list);
252         return 0;
253 }
254 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
255
256 int crypto_register_template(struct crypto_template *tmpl)
257 {
258         struct crypto_template *q;
259         int err = -EEXIST;
260
261         down_write(&crypto_alg_sem);
262
263         list_for_each_entry(q, &crypto_template_list, list) {
264                 if (q == tmpl)
265                         goto out;
266         }
267
268         list_add(&tmpl->list, &crypto_template_list);
269         crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
270         err = 0;
271 out:
272         up_write(&crypto_alg_sem);
273         return err;
274 }
275 EXPORT_SYMBOL_GPL(crypto_register_template);
276
277 void crypto_unregister_template(struct crypto_template *tmpl)
278 {
279         struct crypto_instance *inst;
280         struct hlist_node *p, *n;
281         struct hlist_head *list;
282         LIST_HEAD(users);
283
284         down_write(&crypto_alg_sem);
285
286         BUG_ON(list_empty(&tmpl->list));
287         list_del_init(&tmpl->list);
288
289         list = &tmpl->instances;
290         hlist_for_each_entry(inst, p, list, list) {
291                 int err = crypto_remove_alg(&inst->alg, &users);
292                 BUG_ON(err);
293         }
294
295         crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
296
297         up_write(&crypto_alg_sem);
298
299         hlist_for_each_entry_safe(inst, p, n, list, list) {
300                 BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
301                 tmpl->free(inst);
302         }
303         crypto_remove_final(&users);
304 }
305 EXPORT_SYMBOL_GPL(crypto_unregister_template);
306
307 static struct crypto_template *__crypto_lookup_template(const char *name)
308 {
309         struct crypto_template *q, *tmpl = NULL;
310
311         down_read(&crypto_alg_sem);
312         list_for_each_entry(q, &crypto_template_list, list) {
313                 if (strcmp(q->name, name))
314                         continue;
315                 if (unlikely(!crypto_tmpl_get(q)))
316                         continue;
317
318                 tmpl = q;
319                 break;
320         }
321         up_read(&crypto_alg_sem);
322
323         return tmpl;
324 }
325
326 struct crypto_template *crypto_lookup_template(const char *name)
327 {
328         return try_then_request_module(__crypto_lookup_template(name), name);
329 }
330 EXPORT_SYMBOL_GPL(crypto_lookup_template);
331
332 int crypto_register_instance(struct crypto_template *tmpl,
333                              struct crypto_instance *inst)
334 {
335         LIST_HEAD(list);
336         int err = -EINVAL;
337
338         if (inst->alg.cra_destroy)
339                 goto err;
340
341         err = crypto_check_alg(&inst->alg);
342         if (err)
343                 goto err;
344
345         inst->alg.cra_module = tmpl->module;
346
347         down_write(&crypto_alg_sem);
348
349         err = __crypto_register_alg(&inst->alg, &list);
350         if (err)
351                 goto unlock;
352
353         hlist_add_head(&inst->list, &tmpl->instances);
354         inst->tmpl = tmpl;
355
356 unlock:
357         up_write(&crypto_alg_sem);
358
359         crypto_remove_final(&list);
360
361 err:
362         return err;
363 }
364 EXPORT_SYMBOL_GPL(crypto_register_instance);
365
366 int crypto_init_spawn(struct crypto_spawn *spawn, struct crypto_alg *alg,
367                       struct crypto_instance *inst, u32 mask)
368 {
369         int err = -EAGAIN;
370
371         spawn->inst = inst;
372         spawn->mask = mask;
373
374         down_write(&crypto_alg_sem);
375         if (!crypto_is_moribund(alg)) {
376                 list_add(&spawn->list, &alg->cra_users);
377                 spawn->alg = alg;
378                 err = 0;
379         }
380         up_write(&crypto_alg_sem);
381
382         return err;
383 }
384 EXPORT_SYMBOL_GPL(crypto_init_spawn);
385
386 void crypto_drop_spawn(struct crypto_spawn *spawn)
387 {
388         down_write(&crypto_alg_sem);
389         list_del(&spawn->list);
390         up_write(&crypto_alg_sem);
391 }
392 EXPORT_SYMBOL_GPL(crypto_drop_spawn);
393
394 struct crypto_tfm *crypto_spawn_tfm(struct crypto_spawn *spawn, u32 type,
395                                     u32 mask)
396 {
397         struct crypto_alg *alg;
398         struct crypto_alg *alg2;
399         struct crypto_tfm *tfm;
400
401         down_read(&crypto_alg_sem);
402         alg = spawn->alg;
403         alg2 = alg;
404         if (alg2)
405                 alg2 = crypto_mod_get(alg2);
406         up_read(&crypto_alg_sem);
407
408         if (!alg2) {
409                 if (alg)
410                         crypto_shoot_alg(alg);
411                 return ERR_PTR(-EAGAIN);
412         }
413
414         tfm = ERR_PTR(-EINVAL);
415         if (unlikely((alg->cra_flags ^ type) & mask))
416                 goto out_put_alg;
417
418         tfm = __crypto_alloc_tfm(alg, type, mask);
419         if (IS_ERR(tfm))
420                 goto out_put_alg;
421
422         return tfm;
423
424 out_put_alg:
425         crypto_mod_put(alg);
426         return tfm;
427 }
428 EXPORT_SYMBOL_GPL(crypto_spawn_tfm);
429
430 int crypto_register_notifier(struct notifier_block *nb)
431 {
432         return blocking_notifier_chain_register(&crypto_chain, nb);
433 }
434 EXPORT_SYMBOL_GPL(crypto_register_notifier);
435
436 int crypto_unregister_notifier(struct notifier_block *nb)
437 {
438         return blocking_notifier_chain_unregister(&crypto_chain, nb);
439 }
440 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
441
442 struct crypto_attr_type *crypto_get_attr_type(struct rtattr **tb)
443 {
444         struct rtattr *rta = tb[0];
445         struct crypto_attr_type *algt;
446
447         if (!rta)
448                 return ERR_PTR(-ENOENT);
449         if (RTA_PAYLOAD(rta) < sizeof(*algt))
450                 return ERR_PTR(-EINVAL);
451         if (rta->rta_type != CRYPTOA_TYPE)
452                 return ERR_PTR(-EINVAL);
453
454         algt = RTA_DATA(rta);
455
456         return algt;
457 }
458 EXPORT_SYMBOL_GPL(crypto_get_attr_type);
459
460 int crypto_check_attr_type(struct rtattr **tb, u32 type)
461 {
462         struct crypto_attr_type *algt;
463
464         algt = crypto_get_attr_type(tb);
465         if (IS_ERR(algt))
466                 return PTR_ERR(algt);
467
468         if ((algt->type ^ type) & algt->mask)
469                 return -EINVAL;
470
471         return 0;
472 }
473 EXPORT_SYMBOL_GPL(crypto_check_attr_type);
474
475 struct crypto_alg *crypto_attr_alg(struct rtattr *rta, u32 type, u32 mask)
476 {
477         struct crypto_attr_alg *alga;
478
479         if (!rta)
480                 return ERR_PTR(-ENOENT);
481         if (RTA_PAYLOAD(rta) < sizeof(*alga))
482                 return ERR_PTR(-EINVAL);
483         if (rta->rta_type != CRYPTOA_ALG)
484                 return ERR_PTR(-EINVAL);
485
486         alga = RTA_DATA(rta);
487         alga->name[CRYPTO_MAX_ALG_NAME - 1] = 0;
488
489         return crypto_alg_mod_lookup(alga->name, type, mask);
490 }
491 EXPORT_SYMBOL_GPL(crypto_attr_alg);
492
493 int crypto_attr_u32(struct rtattr *rta, u32 *num)
494 {
495         struct crypto_attr_u32 *nu32;
496
497         if (!rta)
498                 return -ENOENT;
499         if (RTA_PAYLOAD(rta) < sizeof(*nu32))
500                 return -EINVAL;
501         if (rta->rta_type != CRYPTOA_U32)
502                 return -EINVAL;
503
504         nu32 = RTA_DATA(rta);
505         *num = nu32->num;
506
507         return 0;
508 }
509 EXPORT_SYMBOL_GPL(crypto_attr_u32);
510
511 struct crypto_instance *crypto_alloc_instance(const char *name,
512                                               struct crypto_alg *alg)
513 {
514         struct crypto_instance *inst;
515         struct crypto_spawn *spawn;
516         int err;
517
518         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
519         if (!inst)
520                 return ERR_PTR(-ENOMEM);
521
522         err = -ENAMETOOLONG;
523         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", name,
524                      alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
525                 goto err_free_inst;
526
527         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
528                      name, alg->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
529                 goto err_free_inst;
530
531         spawn = crypto_instance_ctx(inst);
532         err = crypto_init_spawn(spawn, alg, inst,
533                                 CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_ASYNC);
534
535         if (err)
536                 goto err_free_inst;
537
538         return inst;
539
540 err_free_inst:
541         kfree(inst);
542         return ERR_PTR(err);
543 }
544 EXPORT_SYMBOL_GPL(crypto_alloc_instance);
545
546 void crypto_init_queue(struct crypto_queue *queue, unsigned int max_qlen)
547 {
548         INIT_LIST_HEAD(&queue->list);
549         queue->backlog = &queue->list;
550         queue->qlen = 0;
551         queue->max_qlen = max_qlen;
552 }
553 EXPORT_SYMBOL_GPL(crypto_init_queue);
554
555 int crypto_enqueue_request(struct crypto_queue *queue,
556                            struct crypto_async_request *request)
557 {
558         int err = -EINPROGRESS;
559
560         if (unlikely(queue->qlen >= queue->max_qlen)) {
561                 err = -EBUSY;
562                 if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
563                         goto out;
564                 if (queue->backlog == &queue->list)
565                         queue->backlog = &request->list;
566         }
567
568         queue->qlen++;
569         list_add_tail(&request->list, &queue->list);
570
571 out:
572         return err;
573 }
574 EXPORT_SYMBOL_GPL(crypto_enqueue_request);
575
576 struct crypto_async_request *crypto_dequeue_request(struct crypto_queue *queue)
577 {
578         struct list_head *request;
579
580         if (unlikely(!queue->qlen))
581                 return NULL;
582
583         queue->qlen--;
584
585         if (queue->backlog != &queue->list)
586                 queue->backlog = queue->backlog->next;
587
588         request = queue->list.next;
589         list_del(request);
590
591         return list_entry(request, struct crypto_async_request, list);
592 }
593 EXPORT_SYMBOL_GPL(crypto_dequeue_request);
594
595 int crypto_tfm_in_queue(struct crypto_queue *queue, struct crypto_tfm *tfm)
596 {
597         struct crypto_async_request *req;
598
599         list_for_each_entry(req, &queue->list, list) {
600                 if (req->tfm == tfm)
601                         return 1;
602         }
603
604         return 0;
605 }
606 EXPORT_SYMBOL_GPL(crypto_tfm_in_queue);
607
608 static int __init crypto_algapi_init(void)
609 {
610         crypto_init_proc();
611         return 0;
612 }
613
614 static void __exit crypto_algapi_exit(void)
615 {
616         crypto_exit_proc();
617 }
618
619 module_init(crypto_algapi_init);
620 module_exit(crypto_algapi_exit);
621
622 MODULE_LICENSE("GPL");
623 MODULE_DESCRIPTION("Cryptographic algorithms API");