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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         /*
261          * If the internal flag is set for a cipher, require a caller to
262          * to invoke the cipher with the internal flag to use that cipher.
263          * Also, if a caller wants to allocate a cipher that may or may
264          * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
265          * !(mask & CRYPTO_ALG_INTERNAL).
266          */
267         if (!((type | mask) & CRYPTO_ALG_INTERNAL))
268                 mask |= CRYPTO_ALG_INTERNAL;
269 
270         larval = crypto_larval_lookup(name, type, mask);
271         if (IS_ERR(larval) || !crypto_is_larval(larval))
272                 return larval;
273 
274         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
275 
276         if (ok == NOTIFY_STOP)
277                 alg = crypto_larval_wait(larval);
278         else {
279                 crypto_mod_put(larval);
280                 alg = ERR_PTR(-ENOENT);
281         }
282         crypto_larval_kill(larval);
283         return alg;
284 }
285 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
286 
287 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
288 {
289         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
290 
291         if (type_obj)
292                 return type_obj->init(tfm, type, mask);
293 
294         switch (crypto_tfm_alg_type(tfm)) {
295         case CRYPTO_ALG_TYPE_CIPHER:
296                 return crypto_init_cipher_ops(tfm);
297 
298         case CRYPTO_ALG_TYPE_COMPRESS:
299                 return crypto_init_compress_ops(tfm);
300 
301         default:
302                 break;
303         }
304 
305         BUG();
306         return -EINVAL;
307 }
308 
309 static void crypto_exit_ops(struct crypto_tfm *tfm)
310 {
311         const struct crypto_type *type = tfm->__crt_alg->cra_type;
312 
313         if (type) {
314                 if (tfm->exit)
315                         tfm->exit(tfm);
316                 return;
317         }
318 
319         switch (crypto_tfm_alg_type(tfm)) {
320         case CRYPTO_ALG_TYPE_CIPHER:
321                 crypto_exit_cipher_ops(tfm);
322                 break;
323 
324         case CRYPTO_ALG_TYPE_COMPRESS:
325                 crypto_exit_compress_ops(tfm);
326                 break;
327 
328         default:
329                 BUG();
330         }
331 }
332 
333 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
334 {
335         const struct crypto_type *type_obj = alg->cra_type;
336         unsigned int len;
337 
338         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
339         if (type_obj)
340                 return len + type_obj->ctxsize(alg, type, mask);
341 
342         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
343         default:
344                 BUG();
345 
346         case CRYPTO_ALG_TYPE_CIPHER:
347                 len += crypto_cipher_ctxsize(alg);
348                 break;
349 
350         case CRYPTO_ALG_TYPE_COMPRESS:
351                 len += crypto_compress_ctxsize(alg);
352                 break;
353         }
354 
355         return len;
356 }
357 
358 void crypto_shoot_alg(struct crypto_alg *alg)
359 {
360         down_write(&crypto_alg_sem);
361         alg->cra_flags |= CRYPTO_ALG_DYING;
362         up_write(&crypto_alg_sem);
363 }
364 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
365 
366 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
367                                       u32 mask)
368 {
369         struct crypto_tfm *tfm = NULL;
370         unsigned int tfm_size;
371         int err = -ENOMEM;
372 
373         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
374         tfm = kzalloc(tfm_size, GFP_KERNEL);
375         if (tfm == NULL)
376                 goto out_err;
377 
378         tfm->__crt_alg = alg;
379 
380         err = crypto_init_ops(tfm, type, mask);
381         if (err)
382                 goto out_free_tfm;
383 
384         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
385                 goto cra_init_failed;
386 
387         goto out;
388 
389 cra_init_failed:
390         crypto_exit_ops(tfm);
391 out_free_tfm:
392         if (err == -EAGAIN)
393                 crypto_shoot_alg(alg);
394         kfree(tfm);
395 out_err:
396         tfm = ERR_PTR(err);
397 out:
398         return tfm;
399 }
400 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
401 
402 /*
403  *      crypto_alloc_base - Locate algorithm and allocate transform
404  *      @alg_name: Name of algorithm
405  *      @type: Type of algorithm
406  *      @mask: Mask for type comparison
407  *
408  *      This function should not be used by new algorithm types.
409  *      Please use crypto_alloc_tfm instead.
410  *
411  *      crypto_alloc_base() will first attempt to locate an already loaded
412  *      algorithm.  If that fails and the kernel supports dynamically loadable
413  *      modules, it will then attempt to load a module of the same name or
414  *      alias.  If that fails it will send a query to any loaded crypto manager
415  *      to construct an algorithm on the fly.  A refcount is grabbed on the
416  *      algorithm which is then associated with the new transform.
417  *
418  *      The returned transform is of a non-determinate type.  Most people
419  *      should use one of the more specific allocation functions such as
420  *      crypto_alloc_blkcipher.
421  *
422  *      In case of error the return value is an error pointer.
423  */
424 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
425 {
426         struct crypto_tfm *tfm;
427         int err;
428 
429         for (;;) {
430                 struct crypto_alg *alg;
431 
432                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
433                 if (IS_ERR(alg)) {
434                         err = PTR_ERR(alg);
435                         goto err;
436                 }
437 
438                 tfm = __crypto_alloc_tfm(alg, type, mask);
439                 if (!IS_ERR(tfm))
440                         return tfm;
441 
442                 crypto_mod_put(alg);
443                 err = PTR_ERR(tfm);
444 
445 err:
446                 if (err != -EAGAIN)
447                         break;
448                 if (fatal_signal_pending(current)) {
449                         err = -EINTR;
450                         break;
451                 }
452         }
453 
454         return ERR_PTR(err);
455 }
456 EXPORT_SYMBOL_GPL(crypto_alloc_base);
457 
458 void *crypto_create_tfm(struct crypto_alg *alg,
459                         const struct crypto_type *frontend)
460 {
461         char *mem;
462         struct crypto_tfm *tfm = NULL;
463         unsigned int tfmsize;
464         unsigned int total;
465         int err = -ENOMEM;
466 
467         tfmsize = frontend->tfmsize;
468         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
469 
470         mem = kzalloc(total, GFP_KERNEL);
471         if (mem == NULL)
472                 goto out_err;
473 
474         tfm = (struct crypto_tfm *)(mem + tfmsize);
475         tfm->__crt_alg = alg;
476 
477         err = frontend->init_tfm(tfm);
478         if (err)
479                 goto out_free_tfm;
480 
481         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
482                 goto cra_init_failed;
483 
484         goto out;
485 
486 cra_init_failed:
487         crypto_exit_ops(tfm);
488 out_free_tfm:
489         if (err == -EAGAIN)
490                 crypto_shoot_alg(alg);
491         kfree(mem);
492 out_err:
493         mem = ERR_PTR(err);
494 out:
495         return mem;
496 }
497 EXPORT_SYMBOL_GPL(crypto_create_tfm);
498 
499 struct crypto_alg *crypto_find_alg(const char *alg_name,
500                                    const struct crypto_type *frontend,
501                                    u32 type, u32 mask)
502 {
503         struct crypto_alg *(*lookup)(const char *name, u32 type, u32 mask) =
504                 crypto_alg_mod_lookup;
505 
506         if (frontend) {
507                 type &= frontend->maskclear;
508                 mask &= frontend->maskclear;
509                 type |= frontend->type;
510                 mask |= frontend->maskset;
511 
512                 if (frontend->lookup)
513                         lookup = frontend->lookup;
514         }
515 
516         return lookup(alg_name, type, mask);
517 }
518 EXPORT_SYMBOL_GPL(crypto_find_alg);
519 
520 /*
521  *      crypto_alloc_tfm - Locate algorithm and allocate transform
522  *      @alg_name: Name of algorithm
523  *      @frontend: Frontend algorithm type
524  *      @type: Type of algorithm
525  *      @mask: Mask for type comparison
526  *
527  *      crypto_alloc_tfm() will first attempt to locate an already loaded
528  *      algorithm.  If that fails and the kernel supports dynamically loadable
529  *      modules, it will then attempt to load a module of the same name or
530  *      alias.  If that fails it will send a query to any loaded crypto manager
531  *      to construct an algorithm on the fly.  A refcount is grabbed on the
532  *      algorithm which is then associated with the new transform.
533  *
534  *      The returned transform is of a non-determinate type.  Most people
535  *      should use one of the more specific allocation functions such as
536  *      crypto_alloc_blkcipher.
537  *
538  *      In case of error the return value is an error pointer.
539  */
540 void *crypto_alloc_tfm(const char *alg_name,
541                        const struct crypto_type *frontend, u32 type, u32 mask)
542 {
543         void *tfm;
544         int err;
545 
546         for (;;) {
547                 struct crypto_alg *alg;
548 
549                 alg = crypto_find_alg(alg_name, frontend, type, mask);
550                 if (IS_ERR(alg)) {
551                         err = PTR_ERR(alg);
552                         goto err;
553                 }
554 
555                 tfm = crypto_create_tfm(alg, frontend);
556                 if (!IS_ERR(tfm))
557                         return tfm;
558 
559                 crypto_mod_put(alg);
560                 err = PTR_ERR(tfm);
561 
562 err:
563                 if (err != -EAGAIN)
564                         break;
565                 if (fatal_signal_pending(current)) {
566                         err = -EINTR;
567                         break;
568                 }
569         }
570 
571         return ERR_PTR(err);
572 }
573 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
574 
575 /*
576  *      crypto_destroy_tfm - Free crypto transform
577  *      @mem: Start of tfm slab
578  *      @tfm: Transform to free
579  *
580  *      This function frees up the transform and any associated resources,
581  *      then drops the refcount on the associated algorithm.
582  */
583 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
584 {
585         struct crypto_alg *alg;
586 
587         if (unlikely(!mem))
588                 return;
589 
590         alg = tfm->__crt_alg;
591 
592         if (!tfm->exit && alg->cra_exit)
593                 alg->cra_exit(tfm);
594         crypto_exit_ops(tfm);
595         crypto_mod_put(alg);
596         kzfree(mem);
597 }
598 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
599 
600 int crypto_has_alg(const char *name, u32 type, u32 mask)
601 {
602         int ret = 0;
603         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
604 
605         if (!IS_ERR(alg)) {
606                 crypto_mod_put(alg);
607                 ret = 1;
608         }
609 
610         return ret;
611 }
612 EXPORT_SYMBOL_GPL(crypto_has_alg);
613 
614 MODULE_DESCRIPTION("Cryptographic core API");
615 MODULE_LICENSE("GPL");
616 

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