f0df85fc1f50b720c1eafe443a77f36aac61195b
[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/errno.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/list.h>
17 #include <linux/module.h>
18 #include <linux/string.h>
19
20 #include "internal.h"
21
22 static LIST_HEAD(crypto_template_list);
23
24 void crypto_larval_error(const char *name)
25 {
26         struct crypto_alg *alg;
27
28         down_read(&crypto_alg_sem);
29         alg = __crypto_alg_lookup(name);
30         up_read(&crypto_alg_sem);
31
32         if (alg) {
33                 if (crypto_is_larval(alg)) {
34                         struct crypto_larval *larval = (void *)alg;
35                         complete(&larval->completion);
36                 }
37                 crypto_mod_put(alg);
38         }
39 }
40 EXPORT_SYMBOL_GPL(crypto_larval_error);
41
42 static inline int crypto_set_driver_name(struct crypto_alg *alg)
43 {
44         static const char suffix[] = "-generic";
45         char *driver_name = alg->cra_driver_name;
46         int len;
47
48         if (*driver_name)
49                 return 0;
50
51         len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
52         if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
53                 return -ENAMETOOLONG;
54
55         memcpy(driver_name + len, suffix, sizeof(suffix));
56         return 0;
57 }
58
59 static int crypto_check_alg(struct crypto_alg *alg)
60 {
61         if (alg->cra_alignmask & (alg->cra_alignmask + 1))
62                 return -EINVAL;
63
64         if (alg->cra_alignmask & alg->cra_blocksize)
65                 return -EINVAL;
66
67         if (alg->cra_blocksize > PAGE_SIZE / 8)
68                 return -EINVAL;
69
70         if (alg->cra_priority < 0)
71                 return -EINVAL;
72
73         return crypto_set_driver_name(alg);
74 }
75
76 static int __crypto_register_alg(struct crypto_alg *alg)
77 {
78         struct crypto_alg *q;
79         int ret = -EEXIST;
80
81         atomic_set(&alg->cra_refcnt, 1);
82         list_for_each_entry(q, &crypto_alg_list, cra_list) {
83                 if (q == alg)
84                         goto out;
85                 if (crypto_is_larval(q) &&
86                     (!strcmp(alg->cra_name, q->cra_name) ||
87                      !strcmp(alg->cra_driver_name, q->cra_name))) {
88                         struct crypto_larval *larval = (void *)q;
89
90                         if (!crypto_mod_get(alg))
91                                 continue;
92                         larval->adult = alg;
93                         complete(&larval->completion);
94                 }
95         }
96         
97         list_add(&alg->cra_list, &crypto_alg_list);
98
99         crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
100         ret = 0;
101
102 out:    
103         return ret;
104 }
105
106 int crypto_register_alg(struct crypto_alg *alg)
107 {
108         int err;
109
110         err = crypto_check_alg(alg);
111         if (err)
112                 return err;
113
114         down_write(&crypto_alg_sem);
115         err = __crypto_register_alg(alg);
116         up_write(&crypto_alg_sem);
117
118         return err;
119 }
120 EXPORT_SYMBOL_GPL(crypto_register_alg);
121
122 int crypto_unregister_alg(struct crypto_alg *alg)
123 {
124         int ret = -ENOENT;
125         
126         down_write(&crypto_alg_sem);
127         if (likely(!list_empty(&alg->cra_list))) {
128                 list_del_init(&alg->cra_list);
129                 ret = 0;
130         }
131         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
132         up_write(&crypto_alg_sem);
133
134         if (ret)
135                 return ret;
136
137         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
138         if (alg->cra_destroy)
139                 alg->cra_destroy(alg);
140
141         return 0;
142 }
143 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
144
145 int crypto_register_template(struct crypto_template *tmpl)
146 {
147         struct crypto_template *q;
148         int err = -EEXIST;
149
150         down_write(&crypto_alg_sem);
151
152         list_for_each_entry(q, &crypto_template_list, list) {
153                 if (q == tmpl)
154                         goto out;
155         }
156
157         list_add(&tmpl->list, &crypto_template_list);
158         crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
159         err = 0;
160 out:
161         up_write(&crypto_alg_sem);
162         return err;
163 }
164 EXPORT_SYMBOL_GPL(crypto_register_template);
165
166 void crypto_unregister_template(struct crypto_template *tmpl)
167 {
168         struct crypto_instance *inst;
169         struct hlist_node *p, *n;
170         struct hlist_head *list;
171
172         down_write(&crypto_alg_sem);
173
174         BUG_ON(list_empty(&tmpl->list));
175         list_del_init(&tmpl->list);
176
177         list = &tmpl->instances;
178         hlist_for_each_entry(inst, p, list, list) {
179                 BUG_ON(list_empty(&inst->alg.cra_list));
180                 list_del_init(&inst->alg.cra_list);
181                 crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
182         }
183
184         crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
185
186         up_write(&crypto_alg_sem);
187
188         hlist_for_each_entry_safe(inst, p, n, list, list) {
189                 BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
190                 tmpl->free(inst);
191         }
192 }
193 EXPORT_SYMBOL_GPL(crypto_unregister_template);
194
195 static struct crypto_template *__crypto_lookup_template(const char *name)
196 {
197         struct crypto_template *q, *tmpl = NULL;
198
199         down_read(&crypto_alg_sem);
200         list_for_each_entry(q, &crypto_template_list, list) {
201                 if (strcmp(q->name, name))
202                         continue;
203                 if (unlikely(!crypto_tmpl_get(q)))
204                         continue;
205
206                 tmpl = q;
207                 break;
208         }
209         up_read(&crypto_alg_sem);
210
211         return tmpl;
212 }
213
214 struct crypto_template *crypto_lookup_template(const char *name)
215 {
216         return try_then_request_module(__crypto_lookup_template(name), name);
217 }
218 EXPORT_SYMBOL_GPL(crypto_lookup_template);
219
220 int crypto_register_instance(struct crypto_template *tmpl,
221                              struct crypto_instance *inst)
222 {
223         int err = -EINVAL;
224
225         if (inst->alg.cra_destroy)
226                 goto err;
227
228         err = crypto_check_alg(&inst->alg);
229         if (err)
230                 goto err;
231
232         inst->alg.cra_module = tmpl->module;
233
234         down_write(&crypto_alg_sem);
235
236         err = __crypto_register_alg(&inst->alg);
237         if (err)
238                 goto unlock;
239
240         hlist_add_head(&inst->list, &tmpl->instances);
241         inst->tmpl = tmpl;
242
243 unlock:
244         up_write(&crypto_alg_sem);
245
246 err:
247         return err;
248 }
249 EXPORT_SYMBOL_GPL(crypto_register_instance);
250
251 int crypto_register_notifier(struct notifier_block *nb)
252 {
253         return blocking_notifier_chain_register(&crypto_chain, nb);
254 }
255 EXPORT_SYMBOL_GPL(crypto_register_notifier);
256
257 int crypto_unregister_notifier(struct notifier_block *nb)
258 {
259         return blocking_notifier_chain_unregister(&crypto_chain, nb);
260 }
261 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
262
263 static int __init crypto_algapi_init(void)
264 {
265         crypto_init_proc();
266         return 0;
267 }
268
269 static void __exit crypto_algapi_exit(void)
270 {
271         crypto_exit_proc();
272 }
273
274 module_init(crypto_algapi_init);
275 module_exit(crypto_algapi_exit);
276
277 MODULE_LICENSE("GPL");
278 MODULE_DESCRIPTION("Cryptographic algorithms API");