Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

Linux/crypto/api.c

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

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