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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 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
38 {
39 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
40 }
41 EXPORT_SYMBOL_GPL(crypto_mod_get);
42
43 void crypto_mod_put(struct crypto_alg *alg)
44 {
45 struct module *module = alg->cra_module;
46
47 crypto_alg_put(alg);
48 module_put(module);
49 }
50 EXPORT_SYMBOL_GPL(crypto_mod_put);
51
52 static inline int crypto_is_test_larval(struct crypto_larval *larval)
53 {
54 return larval->alg.cra_driver_name[0];
55 }
56
57 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
58 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 !crypto_is_test_larval((struct crypto_larval *)q) &&
74 ((struct crypto_larval *)q)->mask != mask)
75 continue;
76
77 exact = !strcmp(q->cra_driver_name, name);
78 fuzzy = !strcmp(q->cra_name, name);
79 if (!exact && !(fuzzy && q->cra_priority > best))
80 continue;
81
82 if (unlikely(!crypto_mod_get(q)))
83 continue;
84
85 best = q->cra_priority;
86 if (alg)
87 crypto_mod_put(alg);
88 alg = q;
89
90 if (exact)
91 break;
92 }
93
94 return alg;
95 }
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 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
108 {
109 struct crypto_larval *larval;
110
111 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
112 if (!larval)
113 return ERR_PTR(-ENOMEM);
114
115 larval->mask = mask;
116 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
117 larval->alg.cra_priority = -1;
118 larval->alg.cra_destroy = crypto_larval_destroy;
119
120 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
121 init_completion(&larval->completion);
122
123 return larval;
124 }
125 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
126
127 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
128 u32 mask)
129 {
130 struct crypto_alg *alg;
131 struct crypto_larval *larval;
132
133 larval = crypto_larval_alloc(name, type, mask);
134 if (IS_ERR(larval))
135 return ERR_CAST(larval);
136
137 atomic_set(&larval->alg.cra_refcnt, 2);
138
139 down_write(&crypto_alg_sem);
140 alg = __crypto_alg_lookup(name, type, mask);
141 if (!alg) {
142 alg = &larval->alg;
143 list_add(&alg->cra_list, &crypto_alg_list);
144 }
145 up_write(&crypto_alg_sem);
146
147 if (alg != &larval->alg)
148 kfree(larval);
149
150 return alg;
151 }
152
153 void crypto_larval_kill(struct crypto_alg *alg)
154 {
155 struct crypto_larval *larval = (void *)alg;
156
157 down_write(&crypto_alg_sem);
158 list_del(&alg->cra_list);
159 up_write(&crypto_alg_sem);
160 complete_all(&larval->completion);
161 crypto_alg_put(alg);
162 }
163 EXPORT_SYMBOL_GPL(crypto_larval_kill);
164
165 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
166 {
167 struct crypto_larval *larval = (void *)alg;
168 long timeout;
169
170 timeout = wait_for_completion_interruptible_timeout(
171 &larval->completion, 60 * HZ);
172
173 alg = larval->adult;
174 if (timeout < 0)
175 alg = ERR_PTR(-EINTR);
176 else if (!timeout)
177 alg = ERR_PTR(-ETIMEDOUT);
178 else if (!alg)
179 alg = ERR_PTR(-ENOENT);
180 else if (crypto_is_test_larval(larval) &&
181 !(alg->cra_flags & CRYPTO_ALG_TESTED))
182 alg = ERR_PTR(-EAGAIN);
183 else if (!crypto_mod_get(alg))
184 alg = ERR_PTR(-EAGAIN);
185 crypto_mod_put(&larval->alg);
186
187 return alg;
188 }
189
190 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
191 {
192 struct crypto_alg *alg;
193
194 down_read(&crypto_alg_sem);
195 alg = __crypto_alg_lookup(name, type, mask);
196 up_read(&crypto_alg_sem);
197
198 return alg;
199 }
200 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
201
202 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
203 {
204 struct crypto_alg *alg;
205
206 if (!name)
207 return ERR_PTR(-ENOENT);
208
209 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
210 type &= mask;
211
212 alg = crypto_alg_lookup(name, type, mask);
213 if (!alg) {
214 request_module("%s", name);
215
216 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
217 CRYPTO_ALG_NEED_FALLBACK))
218 request_module("%s-all", name);
219
220 alg = crypto_alg_lookup(name, type, mask);
221 }
222
223 if (alg)
224 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
225
226 return crypto_larval_add(name, type, mask);
227 }
228 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
229
230 int crypto_probing_notify(unsigned long val, void *v)
231 {
232 int ok;
233
234 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
235 if (ok == NOTIFY_DONE) {
236 request_module("cryptomgr");
237 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
238 }
239
240 return ok;
241 }
242 EXPORT_SYMBOL_GPL(crypto_probing_notify);
243
244 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
245 {
246 struct crypto_alg *alg;
247 struct crypto_alg *larval;
248 int ok;
249
250 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
251 type |= CRYPTO_ALG_TESTED;
252 mask |= CRYPTO_ALG_TESTED;
253 }
254
255 larval = crypto_larval_lookup(name, type, mask);
256 if (IS_ERR(larval) || !crypto_is_larval(larval))
257 return larval;
258
259 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
260
261 if (ok == NOTIFY_STOP)
262 alg = crypto_larval_wait(larval);
263 else {
264 crypto_mod_put(larval);
265 alg = ERR_PTR(-ENOENT);
266 }
267 crypto_larval_kill(larval);
268 return alg;
269 }
270 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
271
272 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
273 {
274 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
275
276 if (type_obj)
277 return type_obj->init(tfm, type, mask);
278
279 switch (crypto_tfm_alg_type(tfm)) {
280 case CRYPTO_ALG_TYPE_CIPHER:
281 return crypto_init_cipher_ops(tfm);
282
283 case CRYPTO_ALG_TYPE_COMPRESS:
284 return crypto_init_compress_ops(tfm);
285
286 default:
287 break;
288 }
289
290 BUG();
291 return -EINVAL;
292 }
293
294 static void crypto_exit_ops(struct crypto_tfm *tfm)
295 {
296 const struct crypto_type *type = tfm->__crt_alg->cra_type;
297
298 if (type) {
299 if (tfm->exit)
300 tfm->exit(tfm);
301 return;
302 }
303
304 switch (crypto_tfm_alg_type(tfm)) {
305 case CRYPTO_ALG_TYPE_CIPHER:
306 crypto_exit_cipher_ops(tfm);
307 break;
308
309 case CRYPTO_ALG_TYPE_COMPRESS:
310 crypto_exit_compress_ops(tfm);
311 break;
312
313 default:
314 BUG();
315 }
316 }
317
318 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
319 {
320 const struct crypto_type *type_obj = alg->cra_type;
321 unsigned int len;
322
323 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
324 if (type_obj)
325 return len + type_obj->ctxsize(alg, type, mask);
326
327 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
328 default:
329 BUG();
330
331 case CRYPTO_ALG_TYPE_CIPHER:
332 len += crypto_cipher_ctxsize(alg);
333 break;
334
335 case CRYPTO_ALG_TYPE_COMPRESS:
336 len += crypto_compress_ctxsize(alg);
337 break;
338 }
339
340 return len;
341 }
342
343 void crypto_shoot_alg(struct crypto_alg *alg)
344 {
345 down_write(&crypto_alg_sem);
346 alg->cra_flags |= CRYPTO_ALG_DYING;
347 up_write(&crypto_alg_sem);
348 }
349 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
350
351 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
352 u32 mask)
353 {
354 struct crypto_tfm *tfm = NULL;
355 unsigned int tfm_size;
356 int err = -ENOMEM;
357
358 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
359 tfm = kzalloc(tfm_size, GFP_KERNEL);
360 if (tfm == NULL)
361 goto out_err;
362
363 tfm->__crt_alg = alg;
364
365 err = crypto_init_ops(tfm, type, mask);
366 if (err)
367 goto out_free_tfm;
368
369 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
370 goto cra_init_failed;
371
372 goto out;
373
374 cra_init_failed:
375 crypto_exit_ops(tfm);
376 out_free_tfm:
377 if (err == -EAGAIN)
378 crypto_shoot_alg(alg);
379 kfree(tfm);
380 out_err:
381 tfm = ERR_PTR(err);
382 out:
383 return tfm;
384 }
385 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
386
387 /*
388 * crypto_alloc_base - Locate algorithm and allocate transform
389 * @alg_name: Name of algorithm
390 * @type: Type of algorithm
391 * @mask: Mask for type comparison
392 *
393 * This function should not be used by new algorithm types.
394 * Plesae use crypto_alloc_tfm instead.
395 *
396 * crypto_alloc_base() will first attempt to locate an already loaded
397 * algorithm. If that fails and the kernel supports dynamically loadable
398 * modules, it will then attempt to load a module of the same name or
399 * alias. If that fails it will send a query to any loaded crypto manager
400 * to construct an algorithm on the fly. A refcount is grabbed on the
401 * algorithm which is then associated with the new transform.
402 *
403 * The returned transform is of a non-determinate type. Most people
404 * should use one of the more specific allocation functions such as
405 * crypto_alloc_blkcipher.
406 *
407 * In case of error the return value is an error pointer.
408 */
409 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
410 {
411 struct crypto_tfm *tfm;
412 int err;
413
414 for (;;) {
415 struct crypto_alg *alg;
416
417 alg = crypto_alg_mod_lookup(alg_name, type, mask);
418 if (IS_ERR(alg)) {
419 err = PTR_ERR(alg);
420 goto err;
421 }
422
423 tfm = __crypto_alloc_tfm(alg, type, mask);
424 if (!IS_ERR(tfm))
425 return tfm;
426
427 crypto_mod_put(alg);
428 err = PTR_ERR(tfm);
429
430 err:
431 if (err != -EAGAIN)
432 break;
433 if (signal_pending(current)) {
434 err = -EINTR;
435 break;
436 }
437 }
438
439 return ERR_PTR(err);
440 }
441 EXPORT_SYMBOL_GPL(crypto_alloc_base);
442
443 void *crypto_create_tfm(struct crypto_alg *alg,
444 const struct crypto_type *frontend)
445 {
446 char *mem;
447 struct crypto_tfm *tfm = NULL;
448 unsigned int tfmsize;
449 unsigned int total;
450 int err = -ENOMEM;
451
452 tfmsize = frontend->tfmsize;
453 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
454
455 mem = kzalloc(total, GFP_KERNEL);
456 if (mem == NULL)
457 goto out_err;
458
459 tfm = (struct crypto_tfm *)(mem + tfmsize);
460 tfm->__crt_alg = alg;
461
462 err = frontend->init_tfm(tfm);
463 if (err)
464 goto out_free_tfm;
465
466 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
467 goto cra_init_failed;
468
469 goto out;
470
471 cra_init_failed:
472 crypto_exit_ops(tfm);
473 out_free_tfm:
474 if (err == -EAGAIN)
475 crypto_shoot_alg(alg);
476 kfree(mem);
477 out_err:
478 mem = ERR_PTR(err);
479 out:
480 return mem;
481 }
482 EXPORT_SYMBOL_GPL(crypto_create_tfm);
483
484 struct crypto_alg *crypto_find_alg(const char *alg_name,
485 const struct crypto_type *frontend,
486 u32 type, u32 mask)
487 {
488 struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
489 crypto_alg_mod_lookup;
490
491 if (frontend) {
492 type &= frontend->maskclear;
493 mask &= frontend->maskclear;
494 type |= frontend->type;
495 mask |= frontend->maskset;
496
497 if (frontend->lookup)
498 lookup = frontend->lookup;
499 }
500
501 return lookup(alg_name, type, mask);
502 }
503 EXPORT_SYMBOL_GPL(crypto_find_alg);
504
505 /*
506 * crypto_alloc_tfm - Locate algorithm and allocate transform
507 * @alg_name: Name of algorithm
508 * @frontend: Frontend algorithm type
509 * @type: Type of algorithm
510 * @mask: Mask for type comparison
511 *
512 * crypto_alloc_tfm() will first attempt to locate an already loaded
513 * algorithm. If that fails and the kernel supports dynamically loadable
514 * modules, it will then attempt to load a module of the same name or
515 * alias. If that fails it will send a query to any loaded crypto manager
516 * to construct an algorithm on the fly. A refcount is grabbed on the
517 * algorithm which is then associated with the new transform.
518 *
519 * The returned transform is of a non-determinate type. Most people
520 * should use one of the more specific allocation functions such as
521 * crypto_alloc_blkcipher.
522 *
523 * In case of error the return value is an error pointer.
524 */
525 void *crypto_alloc_tfm(const char *alg_name,
526 const struct crypto_type *frontend, u32 type, u32 mask)
527 {
528 void *tfm;
529 int err;
530
531 for (;;) {
532 struct crypto_alg *alg;
533
534 alg = crypto_find_alg(alg_name, frontend, type, mask);
535 if (IS_ERR(alg)) {
536 err = PTR_ERR(alg);
537 goto err;
538 }
539
540 tfm = crypto_create_tfm(alg, frontend);
541 if (!IS_ERR(tfm))
542 return tfm;
543
544 crypto_mod_put(alg);
545 err = PTR_ERR(tfm);
546
547 err:
548 if (err != -EAGAIN)
549 break;
550 if (signal_pending(current)) {
551 err = -EINTR;
552 break;
553 }
554 }
555
556 return ERR_PTR(err);
557 }
558 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
559
560 /*
561 * crypto_destroy_tfm - Free crypto transform
562 * @mem: Start of tfm slab
563 * @tfm: Transform to free
564 *
565 * This function frees up the transform and any associated resources,
566 * then drops the refcount on the associated algorithm.
567 */
568 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
569 {
570 struct crypto_alg *alg;
571
572 if (unlikely(!mem))
573 return;
574
575 alg = tfm->__crt_alg;
576
577 if (!tfm->exit && alg->cra_exit)
578 alg->cra_exit(tfm);
579 crypto_exit_ops(tfm);
580 crypto_mod_put(alg);
581 kzfree(mem);
582 }
583 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
584
585 int crypto_has_alg(const char *name, u32 type, u32 mask)
586 {
587 int ret = 0;
588 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
589
590 if (!IS_ERR(alg)) {
591 crypto_mod_put(alg);
592 ret = 1;
593 }
594
595 return ret;
596 }
597 EXPORT_SYMBOL_GPL(crypto_has_alg);
598
599 MODULE_DESCRIPTION("Cryptographic core API");
600 MODULE_LICENSE("GPL");