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 Möller.
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
29 LIST_HEAD(crypto_alg_list);
30 EXPORT_SYMBOL_GPL(crypto_alg_list);
31 DECLARE_RWSEM(crypto_alg_sem);
32 EXPORT_SYMBOL_GPL(crypto_alg_sem);
33
34 BLOCKING_NOTIFIER_HEAD(crypto_chain);
35 EXPORT_SYMBOL_GPL(crypto_chain);
36
37 static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
38 {
39 atomic_inc(&alg->cra_refcnt);
40 return alg;
41 }
42
43 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
44 {
45 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
46 }
47 EXPORT_SYMBOL_GPL(crypto_mod_get);
48
49 void 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 }
56 EXPORT_SYMBOL_GPL(crypto_mod_put);
57
58 struct 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 }
95 EXPORT_SYMBOL_GPL(__crypto_alg_lookup);
96
97 static 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
107 static 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
140 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_all(&larval->completion);
148 crypto_alg_put(alg);
149 }
150 EXPORT_SYMBOL_GPL(crypto_larval_kill);
151
152 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
153 {
154 struct crypto_larval *larval = (void *)alg;
155
156 wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
157 alg = larval->adult;
158 if (alg) {
159 if (!crypto_mod_get(alg))
160 alg = ERR_PTR(-EAGAIN);
161 } else
162 alg = ERR_PTR(-ENOENT);
163 crypto_mod_put(&larval->alg);
164
165 return alg;
166 }
167
168 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
169 u32 mask)
170 {
171 struct crypto_alg *alg;
172
173 down_read(&crypto_alg_sem);
174 alg = __crypto_alg_lookup(name, type, mask);
175 up_read(&crypto_alg_sem);
176
177 return alg;
178 }
179
180 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
181 {
182 struct crypto_alg *alg;
183
184 if (!name)
185 return ERR_PTR(-ENOENT);
186
187 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
188 type &= mask;
189
190 alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
191 name);
192 if (alg)
193 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
194
195 return crypto_larval_alloc(name, type, mask);
196 }
197 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
198
199 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
200 {
201 struct crypto_alg *alg;
202 struct crypto_alg *larval;
203 int ok;
204
205 larval = crypto_larval_lookup(name, type, mask);
206 if (IS_ERR(larval) || !crypto_is_larval(larval))
207 return larval;
208
209 ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
210 if (ok == NOTIFY_DONE) {
211 request_module("cryptomgr");
212 ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
213 }
214
215 if (ok == NOTIFY_STOP)
216 alg = crypto_larval_wait(larval);
217 else {
218 crypto_mod_put(larval);
219 alg = ERR_PTR(-ENOENT);
220 }
221 crypto_larval_kill(larval);
222 return alg;
223 }
224 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
225
226 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
227 {
228 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
229
230 if (type_obj)
231 return type_obj->init(tfm, type, mask);
232
233 switch (crypto_tfm_alg_type(tfm)) {
234 case CRYPTO_ALG_TYPE_CIPHER:
235 return crypto_init_cipher_ops(tfm);
236
237 case CRYPTO_ALG_TYPE_DIGEST:
238 return crypto_init_digest_ops(tfm);
239
240 case CRYPTO_ALG_TYPE_COMPRESS:
241 return crypto_init_compress_ops(tfm);
242
243 default:
244 break;
245 }
246
247 BUG();
248 return -EINVAL;
249 }
250
251 static void crypto_exit_ops(struct crypto_tfm *tfm)
252 {
253 const struct crypto_type *type = tfm->__crt_alg->cra_type;
254
255 if (type) {
256 if (type->exit)
257 type->exit(tfm);
258 return;
259 }
260
261 switch (crypto_tfm_alg_type(tfm)) {
262 case CRYPTO_ALG_TYPE_CIPHER:
263 crypto_exit_cipher_ops(tfm);
264 break;
265
266 case CRYPTO_ALG_TYPE_DIGEST:
267 crypto_exit_digest_ops(tfm);
268 break;
269
270 case CRYPTO_ALG_TYPE_COMPRESS:
271 crypto_exit_compress_ops(tfm);
272 break;
273
274 default:
275 BUG();
276
277 }
278 }
279
280 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
281 {
282 const struct crypto_type *type_obj = alg->cra_type;
283 unsigned int len;
284
285 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
286 if (type_obj)
287 return len + type_obj->ctxsize(alg, type, mask);
288
289 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
290 default:
291 BUG();
292
293 case CRYPTO_ALG_TYPE_CIPHER:
294 len += crypto_cipher_ctxsize(alg);
295 break;
296
297 case CRYPTO_ALG_TYPE_DIGEST:
298 len += crypto_digest_ctxsize(alg);
299 break;
300
301 case CRYPTO_ALG_TYPE_COMPRESS:
302 len += crypto_compress_ctxsize(alg);
303 break;
304 }
305
306 return len;
307 }
308
309 void crypto_shoot_alg(struct crypto_alg *alg)
310 {
311 down_write(&crypto_alg_sem);
312 alg->cra_flags |= CRYPTO_ALG_DYING;
313 up_write(&crypto_alg_sem);
314 }
315 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
316
317 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
318 u32 mask)
319 {
320 struct crypto_tfm *tfm = NULL;
321 unsigned int tfm_size;
322 int err = -ENOMEM;
323
324 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
325 tfm = kzalloc(tfm_size, GFP_KERNEL);
326 if (tfm == NULL)
327 goto out_err;
328
329 tfm->__crt_alg = alg;
330
331 err = crypto_init_ops(tfm, type, mask);
332 if (err)
333 goto out_free_tfm;
334
335 if (alg->cra_init && (err = alg->cra_init(tfm))) {
336 if (err == -EAGAIN)
337 crypto_shoot_alg(alg);
338 goto cra_init_failed;
339 }
340
341 goto out;
342
343 cra_init_failed:
344 crypto_exit_ops(tfm);
345 out_free_tfm:
346 kfree(tfm);
347 out_err:
348 tfm = ERR_PTR(err);
349 out:
350 return tfm;
351 }
352 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
353
354 /*
355 * crypto_alloc_base - Locate algorithm and allocate transform
356 * @alg_name: Name of algorithm
357 * @type: Type of algorithm
358 * @mask: Mask for type comparison
359 *
360 * crypto_alloc_base() will first attempt to locate an already loaded
361 * algorithm. If that fails and the kernel supports dynamically loadable
362 * modules, it will then attempt to load a module of the same name or
363 * alias. If that fails it will send a query to any loaded crypto manager
364 * to construct an algorithm on the fly. A refcount is grabbed on the
365 * algorithm which is then associated with the new transform.
366 *
367 * The returned transform is of a non-determinate type. Most people
368 * should use one of the more specific allocation functions such as
369 * crypto_alloc_blkcipher.
370 *
371 * In case of error the return value is an error pointer.
372 */
373 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
374 {
375 struct crypto_tfm *tfm;
376 int err;
377
378 for (;;) {
379 struct crypto_alg *alg;
380
381 alg = crypto_alg_mod_lookup(alg_name, type, mask);
382 if (IS_ERR(alg)) {
383 err = PTR_ERR(alg);
384 goto err;
385 }
386
387 tfm = __crypto_alloc_tfm(alg, type, mask);
388 if (!IS_ERR(tfm))
389 return tfm;
390
391 crypto_mod_put(alg);
392 err = PTR_ERR(tfm);
393
394 err:
395 if (err != -EAGAIN)
396 break;
397 if (signal_pending(current)) {
398 err = -EINTR;
399 break;
400 }
401 }
402
403 return ERR_PTR(err);
404 }
405 EXPORT_SYMBOL_GPL(crypto_alloc_base);
406
407 /*
408 * crypto_free_tfm - Free crypto transform
409 * @tfm: Transform to free
410 *
411 * crypto_free_tfm() frees up the transform and any associated resources,
412 * then drops the refcount on the associated algorithm.
413 */
414 void crypto_free_tfm(struct crypto_tfm *tfm)
415 {
416 struct crypto_alg *alg;
417 int size;
418
419 if (unlikely(!tfm))
420 return;
421
422 alg = tfm->__crt_alg;
423 size = sizeof(*tfm) + alg->cra_ctxsize;
424
425 if (alg->cra_exit)
426 alg->cra_exit(tfm);
427 crypto_exit_ops(tfm);
428 crypto_mod_put(alg);
429 memset(tfm, 0, size);
430 kfree(tfm);
431 }
432
433 EXPORT_SYMBOL_GPL(crypto_free_tfm);
434
435 int crypto_has_alg(const char *name, u32 type, u32 mask)
436 {
437 int ret = 0;
438 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
439
440 if (!IS_ERR(alg)) {
441 crypto_mod_put(alg);
442 ret = 1;
443 }
444
445 return ret;
446 }
447 EXPORT_SYMBOL_GPL(crypto_has_alg);
448
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