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TOMOYO Linux Cross Reference
Linux/crypto/api.c

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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 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
 38 
 39 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
 40 {
 41         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
 42 }
 43 EXPORT_SYMBOL_GPL(crypto_mod_get);
 44 
 45 void crypto_mod_put(struct crypto_alg *alg)
 46 {
 47         struct module *module = alg->cra_module;
 48 
 49         crypto_alg_put(alg);
 50         module_put(module);
 51 }
 52 EXPORT_SYMBOL_GPL(crypto_mod_put);
 53 
 54 static inline int crypto_is_test_larval(struct crypto_larval *larval)
 55 {
 56         return larval->alg.cra_driver_name[0];
 57 }
 58 
 59 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
 60                                               u32 mask)
 61 {
 62         struct crypto_alg *q, *alg = NULL;
 63         int best = -2;
 64 
 65         list_for_each_entry(q, &crypto_alg_list, cra_list) {
 66                 int exact, fuzzy;
 67 
 68                 if (crypto_is_moribund(q))
 69                         continue;
 70 
 71                 if ((q->cra_flags ^ type) & mask)
 72                         continue;
 73 
 74                 if (crypto_is_larval(q) &&
 75                     !crypto_is_test_larval((struct crypto_larval *)q) &&
 76                     ((struct crypto_larval *)q)->mask != mask)
 77                         continue;
 78 
 79                 exact = !strcmp(q->cra_driver_name, name);
 80                 fuzzy = !strcmp(q->cra_name, name);
 81                 if (!exact && !(fuzzy && q->cra_priority > best))
 82                         continue;
 83 
 84                 if (unlikely(!crypto_mod_get(q)))
 85                         continue;
 86 
 87                 best = q->cra_priority;
 88                 if (alg)
 89                         crypto_mod_put(alg);
 90                 alg = q;
 91 
 92                 if (exact)
 93                         break;
 94         }
 95 
 96         return alg;
 97 }
 98 
 99 static void crypto_larval_destroy(struct crypto_alg *alg)
100 {
101         struct crypto_larval *larval = (void *)alg;
102 
103         BUG_ON(!crypto_is_larval(alg));
104         if (larval->adult)
105                 crypto_mod_put(larval->adult);
106         kfree(larval);
107 }
108 
109 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
110 {
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         strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
123         init_completion(&larval->completion);
124 
125         return larval;
126 }
127 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
128 
129 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
130                                             u32 mask)
131 {
132         struct crypto_alg *alg;
133         struct crypto_larval *larval;
134 
135         larval = crypto_larval_alloc(name, type, mask);
136         if (IS_ERR(larval))
137                 return ERR_CAST(larval);
138 
139         atomic_set(&larval->alg.cra_refcnt, 2);
140 
141         down_write(&crypto_alg_sem);
142         alg = __crypto_alg_lookup(name, type, mask);
143         if (!alg) {
144                 alg = &larval->alg;
145                 list_add(&alg->cra_list, &crypto_alg_list);
146         }
147         up_write(&crypto_alg_sem);
148 
149         if (alg != &larval->alg) {
150                 kfree(larval);
151                 if (crypto_is_larval(alg))
152                         alg = crypto_larval_wait(alg);
153         }
154 
155         return alg;
156 }
157 
158 void crypto_larval_kill(struct crypto_alg *alg)
159 {
160         struct crypto_larval *larval = (void *)alg;
161 
162         down_write(&crypto_alg_sem);
163         list_del(&alg->cra_list);
164         up_write(&crypto_alg_sem);
165         complete_all(&larval->completion);
166         crypto_alg_put(alg);
167 }
168 EXPORT_SYMBOL_GPL(crypto_larval_kill);
169 
170 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
171 {
172         struct crypto_larval *larval = (void *)alg;
173         long timeout;
174 
175         timeout = wait_for_completion_killable_timeout(
176                 &larval->completion, 60 * HZ);
177 
178         alg = larval->adult;
179         if (timeout < 0)
180                 alg = ERR_PTR(-EINTR);
181         else if (!timeout)
182                 alg = ERR_PTR(-ETIMEDOUT);
183         else if (!alg)
184                 alg = ERR_PTR(-ENOENT);
185         else if (crypto_is_test_larval(larval) &&
186                  !(alg->cra_flags & CRYPTO_ALG_TESTED))
187                 alg = ERR_PTR(-EAGAIN);
188         else if (!crypto_mod_get(alg))
189                 alg = ERR_PTR(-EAGAIN);
190         crypto_mod_put(&larval->alg);
191 
192         return alg;
193 }
194 
195 struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
196 {
197         struct crypto_alg *alg;
198 
199         down_read(&crypto_alg_sem);
200         alg = __crypto_alg_lookup(name, type, mask);
201         up_read(&crypto_alg_sem);
202 
203         return alg;
204 }
205 EXPORT_SYMBOL_GPL(crypto_alg_lookup);
206 
207 struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
208 {
209         struct crypto_alg *alg;
210 
211         if (!name)
212                 return ERR_PTR(-ENOENT);
213 
214         mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
215         type &= mask;
216 
217         alg = crypto_alg_lookup(name, type, mask);
218         if (!alg) {
219                 request_module("crypto-%s", name);
220 
221                 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
222                       CRYPTO_ALG_NEED_FALLBACK))
223                         request_module("crypto-%s-all", name);
224 
225                 alg = crypto_alg_lookup(name, type, mask);
226         }
227 
228         if (alg)
229                 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
230 
231         return crypto_larval_add(name, type, mask);
232 }
233 EXPORT_SYMBOL_GPL(crypto_larval_lookup);
234 
235 int crypto_probing_notify(unsigned long val, void *v)
236 {
237         int ok;
238 
239         ok = blocking_notifier_call_chain(&crypto_chain, val, v);
240         if (ok == NOTIFY_DONE) {
241                 request_module("cryptomgr");
242                 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
243         }
244 
245         return ok;
246 }
247 EXPORT_SYMBOL_GPL(crypto_probing_notify);
248 
249 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
250 {
251         struct crypto_alg *alg;
252         struct crypto_alg *larval;
253         int ok;
254 
255         if (!((type | mask) & CRYPTO_ALG_TESTED)) {
256                 type |= CRYPTO_ALG_TESTED;
257                 mask |= CRYPTO_ALG_TESTED;
258         }
259 
260         larval = crypto_larval_lookup(name, type, mask);
261         if (IS_ERR(larval) || !crypto_is_larval(larval))
262                 return larval;
263 
264         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
265 
266         if (ok == NOTIFY_STOP)
267                 alg = crypto_larval_wait(larval);
268         else {
269                 crypto_mod_put(larval);
270                 alg = ERR_PTR(-ENOENT);
271         }
272         crypto_larval_kill(larval);
273         return alg;
274 }
275 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
276 
277 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
278 {
279         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
280 
281         if (type_obj)
282                 return type_obj->init(tfm, type, mask);
283 
284         switch (crypto_tfm_alg_type(tfm)) {
285         case CRYPTO_ALG_TYPE_CIPHER:
286                 return crypto_init_cipher_ops(tfm);
287 
288         case CRYPTO_ALG_TYPE_COMPRESS:
289                 return crypto_init_compress_ops(tfm);
290 
291         default:
292                 break;
293         }
294 
295         BUG();
296         return -EINVAL;
297 }
298 
299 static void crypto_exit_ops(struct crypto_tfm *tfm)
300 {
301         const struct crypto_type *type = tfm->__crt_alg->cra_type;
302 
303         if (type) {
304                 if (tfm->exit)
305                         tfm->exit(tfm);
306                 return;
307         }
308 
309         switch (crypto_tfm_alg_type(tfm)) {
310         case CRYPTO_ALG_TYPE_CIPHER:
311                 crypto_exit_cipher_ops(tfm);
312                 break;
313 
314         case CRYPTO_ALG_TYPE_COMPRESS:
315                 crypto_exit_compress_ops(tfm);
316                 break;
317 
318         default:
319                 BUG();
320         }
321 }
322 
323 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
324 {
325         const struct crypto_type *type_obj = alg->cra_type;
326         unsigned int len;
327 
328         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
329         if (type_obj)
330                 return len + type_obj->ctxsize(alg, type, mask);
331 
332         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
333         default:
334                 BUG();
335 
336         case CRYPTO_ALG_TYPE_CIPHER:
337                 len += crypto_cipher_ctxsize(alg);
338                 break;
339 
340         case CRYPTO_ALG_TYPE_COMPRESS:
341                 len += crypto_compress_ctxsize(alg);
342                 break;
343         }
344 
345         return len;
346 }
347 
348 void crypto_shoot_alg(struct crypto_alg *alg)
349 {
350         down_write(&crypto_alg_sem);
351         alg->cra_flags |= CRYPTO_ALG_DYING;
352         up_write(&crypto_alg_sem);
353 }
354 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
355 
356 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
357                                       u32 mask)
358 {
359         struct crypto_tfm *tfm = NULL;
360         unsigned int tfm_size;
361         int err = -ENOMEM;
362 
363         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
364         tfm = kzalloc(tfm_size, GFP_KERNEL);
365         if (tfm == NULL)
366                 goto out_err;
367 
368         tfm->__crt_alg = alg;
369 
370         err = crypto_init_ops(tfm, type, mask);
371         if (err)
372                 goto out_free_tfm;
373 
374         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
375                 goto cra_init_failed;
376 
377         goto out;
378 
379 cra_init_failed:
380         crypto_exit_ops(tfm);
381 out_free_tfm:
382         if (err == -EAGAIN)
383                 crypto_shoot_alg(alg);
384         kfree(tfm);
385 out_err:
386         tfm = ERR_PTR(err);
387 out:
388         return tfm;
389 }
390 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
391 
392 /*
393  *      crypto_alloc_base - Locate algorithm and allocate transform
394  *      @alg_name: Name of algorithm
395  *      @type: Type of algorithm
396  *      @mask: Mask for type comparison
397  *
398  *      This function should not be used by new algorithm types.
399  *      Please use crypto_alloc_tfm instead.
400  *
401  *      crypto_alloc_base() will first attempt to locate an already loaded
402  *      algorithm.  If that fails and the kernel supports dynamically loadable
403  *      modules, it will then attempt to load a module of the same name or
404  *      alias.  If that fails it will send a query to any loaded crypto manager
405  *      to construct an algorithm on the fly.  A refcount is grabbed on the
406  *      algorithm which is then associated with the new transform.
407  *
408  *      The returned transform is of a non-determinate type.  Most people
409  *      should use one of the more specific allocation functions such as
410  *      crypto_alloc_blkcipher.
411  *
412  *      In case of error the return value is an error pointer.
413  */
414 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
415 {
416         struct crypto_tfm *tfm;
417         int err;
418 
419         for (;;) {
420                 struct crypto_alg *alg;
421 
422                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
423                 if (IS_ERR(alg)) {
424                         err = PTR_ERR(alg);
425                         goto err;
426                 }
427 
428                 tfm = __crypto_alloc_tfm(alg, type, mask);
429                 if (!IS_ERR(tfm))
430                         return tfm;
431 
432                 crypto_mod_put(alg);
433                 err = PTR_ERR(tfm);
434 
435 err:
436                 if (err != -EAGAIN)
437                         break;
438                 if (fatal_signal_pending(current)) {
439                         err = -EINTR;
440                         break;
441                 }
442         }
443 
444         return ERR_PTR(err);
445 }
446 EXPORT_SYMBOL_GPL(crypto_alloc_base);
447 
448 void *crypto_create_tfm(struct crypto_alg *alg,
449                         const struct crypto_type *frontend)
450 {
451         char *mem;
452         struct crypto_tfm *tfm = NULL;
453         unsigned int tfmsize;
454         unsigned int total;
455         int err = -ENOMEM;
456 
457         tfmsize = frontend->tfmsize;
458         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
459 
460         mem = kzalloc(total, GFP_KERNEL);
461         if (mem == NULL)
462                 goto out_err;
463 
464         tfm = (struct crypto_tfm *)(mem + tfmsize);
465         tfm->__crt_alg = alg;
466 
467         err = frontend->init_tfm(tfm);
468         if (err)
469                 goto out_free_tfm;
470 
471         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
472                 goto cra_init_failed;
473 
474         goto out;
475 
476 cra_init_failed:
477         crypto_exit_ops(tfm);
478 out_free_tfm:
479         if (err == -EAGAIN)
480                 crypto_shoot_alg(alg);
481         kfree(mem);
482 out_err:
483         mem = ERR_PTR(err);
484 out:
485         return mem;
486 }
487 EXPORT_SYMBOL_GPL(crypto_create_tfm);
488 
489 struct crypto_alg *crypto_find_alg(const char *alg_name,
490                                    const struct crypto_type *frontend,
491                                    u32 type, u32 mask)
492 {
493         struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
494                 crypto_alg_mod_lookup;
495 
496         if (frontend) {
497                 type &= frontend->maskclear;
498                 mask &= frontend->maskclear;
499                 type |= frontend->type;
500                 mask |= frontend->maskset;
501 
502                 if (frontend->lookup)
503                         lookup = frontend->lookup;
504         }
505 
506         return lookup(alg_name, type, mask);
507 }
508 EXPORT_SYMBOL_GPL(crypto_find_alg);
509 
510 /*
511  *      crypto_alloc_tfm - Locate algorithm and allocate transform
512  *      @alg_name: Name of algorithm
513  *      @frontend: Frontend algorithm type
514  *      @type: Type of algorithm
515  *      @mask: Mask for type comparison
516  *
517  *      crypto_alloc_tfm() will first attempt to locate an already loaded
518  *      algorithm.  If that fails and the kernel supports dynamically loadable
519  *      modules, it will then attempt to load a module of the same name or
520  *      alias.  If that fails it will send a query to any loaded crypto manager
521  *      to construct an algorithm on the fly.  A refcount is grabbed on the
522  *      algorithm which is then associated with the new transform.
523  *
524  *      The returned transform is of a non-determinate type.  Most people
525  *      should use one of the more specific allocation functions such as
526  *      crypto_alloc_blkcipher.
527  *
528  *      In case of error the return value is an error pointer.
529  */
530 void *crypto_alloc_tfm(const char *alg_name,
531                        const struct crypto_type *frontend, u32 type, u32 mask)
532 {
533         void *tfm;
534         int err;
535 
536         for (;;) {
537                 struct crypto_alg *alg;
538 
539                 alg = crypto_find_alg(alg_name, frontend, type, mask);
540                 if (IS_ERR(alg)) {
541                         err = PTR_ERR(alg);
542                         goto err;
543                 }
544 
545                 tfm = crypto_create_tfm(alg, frontend);
546                 if (!IS_ERR(tfm))
547                         return tfm;
548 
549                 crypto_mod_put(alg);
550                 err = PTR_ERR(tfm);
551 
552 err:
553                 if (err != -EAGAIN)
554                         break;
555                 if (fatal_signal_pending(current)) {
556                         err = -EINTR;
557                         break;
558                 }
559         }
560 
561         return ERR_PTR(err);
562 }
563 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
564 
565 /*
566  *      crypto_destroy_tfm - Free crypto transform
567  *      @mem: Start of tfm slab
568  *      @tfm: Transform to free
569  *
570  *      This function frees up the transform and any associated resources,
571  *      then drops the refcount on the associated algorithm.
572  */
573 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
574 {
575         struct crypto_alg *alg;
576 
577         if (unlikely(!mem))
578                 return;
579 
580         alg = tfm->__crt_alg;
581 
582         if (!tfm->exit && alg->cra_exit)
583                 alg->cra_exit(tfm);
584         crypto_exit_ops(tfm);
585         crypto_mod_put(alg);
586         kzfree(mem);
587 }
588 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
589 
590 int crypto_has_alg(const char *name, u32 type, u32 mask)
591 {
592         int ret = 0;
593         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
594 
595         if (!IS_ERR(alg)) {
596                 crypto_mod_put(alg);
597                 ret = 1;
598         }
599 
600         return ret;
601 }
602 EXPORT_SYMBOL_GPL(crypto_has_alg);
603 
604 MODULE_DESCRIPTION("Cryptographic core API");
605 MODULE_LICENSE("GPL");
606 

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