[CRYPTO] api: Allow algorithm lookup by type
[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, u32 type, u32 mask)
25 {
26         struct crypto_alg *alg;
27
28         down_read(&crypto_alg_sem);
29         alg = __crypto_alg_lookup(name, type, mask);
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 ((q->cra_flags ^ alg->cra_flags) & larval->mask)
91                                 continue;
92                         if (!crypto_mod_get(alg))
93                                 continue;
94                         larval->adult = alg;
95                         complete(&larval->completion);
96                 }
97         }
98         
99         list_add(&alg->cra_list, &crypto_alg_list);
100
101         crypto_notify(CRYPTO_MSG_ALG_REGISTER, alg);
102         ret = 0;
103
104 out:    
105         return ret;
106 }
107
108 int crypto_register_alg(struct crypto_alg *alg)
109 {
110         int err;
111
112         err = crypto_check_alg(alg);
113         if (err)
114                 return err;
115
116         down_write(&crypto_alg_sem);
117         err = __crypto_register_alg(alg);
118         up_write(&crypto_alg_sem);
119
120         return err;
121 }
122 EXPORT_SYMBOL_GPL(crypto_register_alg);
123
124 int crypto_unregister_alg(struct crypto_alg *alg)
125 {
126         int ret = -ENOENT;
127         
128         down_write(&crypto_alg_sem);
129         if (likely(!list_empty(&alg->cra_list))) {
130                 list_del_init(&alg->cra_list);
131                 ret = 0;
132         }
133         crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, alg);
134         up_write(&crypto_alg_sem);
135
136         if (ret)
137                 return ret;
138
139         BUG_ON(atomic_read(&alg->cra_refcnt) != 1);
140         if (alg->cra_destroy)
141                 alg->cra_destroy(alg);
142
143         return 0;
144 }
145 EXPORT_SYMBOL_GPL(crypto_unregister_alg);
146
147 int crypto_register_template(struct crypto_template *tmpl)
148 {
149         struct crypto_template *q;
150         int err = -EEXIST;
151
152         down_write(&crypto_alg_sem);
153
154         list_for_each_entry(q, &crypto_template_list, list) {
155                 if (q == tmpl)
156                         goto out;
157         }
158
159         list_add(&tmpl->list, &crypto_template_list);
160         crypto_notify(CRYPTO_MSG_TMPL_REGISTER, tmpl);
161         err = 0;
162 out:
163         up_write(&crypto_alg_sem);
164         return err;
165 }
166 EXPORT_SYMBOL_GPL(crypto_register_template);
167
168 void crypto_unregister_template(struct crypto_template *tmpl)
169 {
170         struct crypto_instance *inst;
171         struct hlist_node *p, *n;
172         struct hlist_head *list;
173
174         down_write(&crypto_alg_sem);
175
176         BUG_ON(list_empty(&tmpl->list));
177         list_del_init(&tmpl->list);
178
179         list = &tmpl->instances;
180         hlist_for_each_entry(inst, p, list, list) {
181                 BUG_ON(list_empty(&inst->alg.cra_list));
182                 list_del_init(&inst->alg.cra_list);
183                 crypto_notify(CRYPTO_MSG_ALG_UNREGISTER, &inst->alg);
184         }
185
186         crypto_notify(CRYPTO_MSG_TMPL_UNREGISTER, tmpl);
187
188         up_write(&crypto_alg_sem);
189
190         hlist_for_each_entry_safe(inst, p, n, list, list) {
191                 BUG_ON(atomic_read(&inst->alg.cra_refcnt) != 1);
192                 tmpl->free(inst);
193         }
194 }
195 EXPORT_SYMBOL_GPL(crypto_unregister_template);
196
197 static struct crypto_template *__crypto_lookup_template(const char *name)
198 {
199         struct crypto_template *q, *tmpl = NULL;
200
201         down_read(&crypto_alg_sem);
202         list_for_each_entry(q, &crypto_template_list, list) {
203                 if (strcmp(q->name, name))
204                         continue;
205                 if (unlikely(!crypto_tmpl_get(q)))
206                         continue;
207
208                 tmpl = q;
209                 break;
210         }
211         up_read(&crypto_alg_sem);
212
213         return tmpl;
214 }
215
216 struct crypto_template *crypto_lookup_template(const char *name)
217 {
218         return try_then_request_module(__crypto_lookup_template(name), name);
219 }
220 EXPORT_SYMBOL_GPL(crypto_lookup_template);
221
222 int crypto_register_instance(struct crypto_template *tmpl,
223                              struct crypto_instance *inst)
224 {
225         int err = -EINVAL;
226
227         if (inst->alg.cra_destroy)
228                 goto err;
229
230         err = crypto_check_alg(&inst->alg);
231         if (err)
232                 goto err;
233
234         inst->alg.cra_module = tmpl->module;
235
236         down_write(&crypto_alg_sem);
237
238         err = __crypto_register_alg(&inst->alg);
239         if (err)
240                 goto unlock;
241
242         hlist_add_head(&inst->list, &tmpl->instances);
243         inst->tmpl = tmpl;
244
245 unlock:
246         up_write(&crypto_alg_sem);
247
248 err:
249         return err;
250 }
251 EXPORT_SYMBOL_GPL(crypto_register_instance);
252
253 int crypto_register_notifier(struct notifier_block *nb)
254 {
255         return blocking_notifier_chain_register(&crypto_chain, nb);
256 }
257 EXPORT_SYMBOL_GPL(crypto_register_notifier);
258
259 int crypto_unregister_notifier(struct notifier_block *nb)
260 {
261         return blocking_notifier_chain_unregister(&crypto_chain, nb);
262 }
263 EXPORT_SYMBOL_GPL(crypto_unregister_notifier);
264
265 static int __init crypto_algapi_init(void)
266 {
267         crypto_init_proc();
268         return 0;
269 }
270
271 static void __exit crypto_algapi_exit(void)
272 {
273         crypto_exit_proc();
274 }
275
276 module_init(crypto_algapi_init);
277 module_exit(crypto_algapi_exit);
278
279 MODULE_LICENSE("GPL");
280 MODULE_DESCRIPTION("Cryptographic algorithms API");