projects/linux·blob v4.15 · refs

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1/*
2 * Scatterlist Cryptographic API.
3 *
4 * Copyright (c) 2002 James Morris <[email protected]>
5 * Copyright (c) 2002 David S. Miller ([email protected])
6 * Copyright (c) 2005 Herbert Xu <[email protected]>
7 *
8 * Portions derived from Cryptoapi, by Alexander Kjeldaas <[email protected]>
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/signal.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <linux/completion.h>
28#include "internal.h"
29
30LIST_HEAD(crypto_alg_list);
31EXPORT_SYMBOL_GPL(crypto_alg_list);
32DECLARE_RWSEM(crypto_alg_sem);
33EXPORT_SYMBOL_GPL(crypto_alg_sem);
34
35BLOCKING_NOTIFIER_HEAD(crypto_chain);
36EXPORT_SYMBOL_GPL(crypto_chain);
37
38static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
39
40struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
41{
42 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
43}
44EXPORT_SYMBOL_GPL(crypto_mod_get);
45
46void crypto_mod_put(struct crypto_alg *alg)
47{
48 struct module *module = alg->cra_module;
49
50 crypto_alg_put(alg);
51 module_put(module);
52}
53EXPORT_SYMBOL_GPL(crypto_mod_put);
54
55static inline int crypto_is_test_larval(struct crypto_larval *larval)
56{
57 return larval->alg.cra_driver_name[0];
58}
59
60static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
61 u32 mask)
62{
63 struct crypto_alg *q, *alg = NULL;
64 int best = -2;
65
66 list_for_each_entry(q, &crypto_alg_list, cra_list) {
67 int exact, fuzzy;
68
69 if (crypto_is_moribund(q))
70 continue;
71
72 if ((q->cra_flags ^ type) & mask)
73 continue;
74
75 if (crypto_is_larval(q) &&
76 !crypto_is_test_larval((struct crypto_larval *)q) &&
77 ((struct crypto_larval *)q)->mask != mask)
78 continue;
79
80 exact = !strcmp(q->cra_driver_name, name);
81 fuzzy = !strcmp(q->cra_name, name);
82 if (!exact && !(fuzzy && q->cra_priority > best))
83 continue;
84
85 if (unlikely(!crypto_mod_get(q)))
86 continue;
87
88 best = q->cra_priority;
89 if (alg)
90 crypto_mod_put(alg);
91 alg = q;
92
93 if (exact)
94 break;
95 }
96
97 return alg;
98}
99
100static void crypto_larval_destroy(struct crypto_alg *alg)
101{
102 struct crypto_larval *larval = (void *)alg;
103
104 BUG_ON(!crypto_is_larval(alg));
105 if (larval->adult)
106 crypto_mod_put(larval->adult);
107 kfree(larval);
108}
109
110struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
111{
112 struct crypto_larval *larval;
113
114 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
115 if (!larval)
116 return ERR_PTR(-ENOMEM);
117
118 larval->mask = mask;
119 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
120 larval->alg.cra_priority = -1;
121 larval->alg.cra_destroy = crypto_larval_destroy;
122
123 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
124 init_completion(&larval->completion);
125
126 return larval;
127}
128EXPORT_SYMBOL_GPL(crypto_larval_alloc);
129
130static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
131 u32 mask)
132{
133 struct crypto_alg *alg;
134 struct crypto_larval *larval;
135
136 larval = crypto_larval_alloc(name, type, mask);
137 if (IS_ERR(larval))
138 return ERR_CAST(larval);
139
140 atomic_set(&larval->alg.cra_refcnt, 2);
141
142 down_write(&crypto_alg_sem);
143 alg = __crypto_alg_lookup(name, type, mask);
144 if (!alg) {
145 alg = &larval->alg;
146 list_add(&alg->cra_list, &crypto_alg_list);
147 }
148 up_write(&crypto_alg_sem);
149
150 if (alg != &larval->alg) {
151 kfree(larval);
152 if (crypto_is_larval(alg))
153 alg = crypto_larval_wait(alg);
154 }
155
156 return alg;
157}
158
159void crypto_larval_kill(struct crypto_alg *alg)
160{
161 struct crypto_larval *larval = (void *)alg;
162
163 down_write(&crypto_alg_sem);
164 list_del(&alg->cra_list);
165 up_write(&crypto_alg_sem);
166 complete_all(&larval->completion);
167 crypto_alg_put(alg);
168}
169EXPORT_SYMBOL_GPL(crypto_larval_kill);
170
171static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
172{
173 struct crypto_larval *larval = (void *)alg;
174 long timeout;
175
176 timeout = wait_for_completion_killable_timeout(
177 &larval->completion, 60 * HZ);
178
179 alg = larval->adult;
180 if (timeout < 0)
181 alg = ERR_PTR(-EINTR);
182 else if (!timeout)
183 alg = ERR_PTR(-ETIMEDOUT);
184 else if (!alg)
185 alg = ERR_PTR(-ENOENT);
186 else if (crypto_is_test_larval(larval) &&
187 !(alg->cra_flags & CRYPTO_ALG_TESTED))
188 alg = ERR_PTR(-EAGAIN);
189 else if (!crypto_mod_get(alg))
190 alg = ERR_PTR(-EAGAIN);
191 crypto_mod_put(&larval->alg);
192
193 return alg;
194}
195
196struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask)
197{
198 struct crypto_alg *alg;
199
200 down_read(&crypto_alg_sem);
201 alg = __crypto_alg_lookup(name, type, mask);
202 up_read(&crypto_alg_sem);
203
204 return alg;
205}
206EXPORT_SYMBOL_GPL(crypto_alg_lookup);
207
208struct crypto_alg *crypto_larval_lookup(const char *name, u32 type, u32 mask)
209{
210 struct crypto_alg *alg;
211
212 if (!name)
213 return ERR_PTR(-ENOENT);
214
215 type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
216 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
217
218 alg = crypto_alg_lookup(name, type, mask);
219 if (!alg) {
220 request_module("crypto-%s", name);
221
222 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
223 CRYPTO_ALG_NEED_FALLBACK))
224 request_module("crypto-%s-all", name);
225
226 alg = crypto_alg_lookup(name, type, mask);
227 }
228
229 if (alg)
230 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
231
232 return crypto_larval_add(name, type, mask);
233}
234EXPORT_SYMBOL_GPL(crypto_larval_lookup);
235
236int crypto_probing_notify(unsigned long val, void *v)
237{
238 int ok;
239
240 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
241 if (ok == NOTIFY_DONE) {
242 request_module("cryptomgr");
243 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
244 }
245
246 return ok;
247}
248EXPORT_SYMBOL_GPL(crypto_probing_notify);
249
250struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
251{
252 struct crypto_alg *alg;
253 struct crypto_alg *larval;
254 int ok;
255
256 if (!((type | mask) & CRYPTO_ALG_TESTED)) {
257 type |= CRYPTO_ALG_TESTED;
258 mask |= CRYPTO_ALG_TESTED;
259 }
260
261 /*
262 * If the internal flag is set for a cipher, require a caller to
263 * to invoke the cipher with the internal flag to use that cipher.
264 * Also, if a caller wants to allocate a cipher that may or may
265 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
266 * !(mask & CRYPTO_ALG_INTERNAL).
267 */
268 if (!((type | mask) & CRYPTO_ALG_INTERNAL))
269 mask |= CRYPTO_ALG_INTERNAL;
270
271 larval = crypto_larval_lookup(name, type, mask);
272 if (IS_ERR(larval) || !crypto_is_larval(larval))
273 return larval;
274
275 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
276
277 if (ok == NOTIFY_STOP)
278 alg = crypto_larval_wait(larval);
279 else {
280 crypto_mod_put(larval);
281 alg = ERR_PTR(-ENOENT);
282 }
283 crypto_larval_kill(larval);
284 return alg;
285}
286EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
287
288static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
289{
290 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
291
292 if (type_obj)
293 return type_obj->init(tfm, type, mask);
294
295 switch (crypto_tfm_alg_type(tfm)) {
296 case CRYPTO_ALG_TYPE_CIPHER:
297 return crypto_init_cipher_ops(tfm);
298
299 case CRYPTO_ALG_TYPE_COMPRESS:
300 return crypto_init_compress_ops(tfm);
301
302 default:
303 break;
304 }
305
306 BUG();
307 return -EINVAL;
308}
309
310static void crypto_exit_ops(struct crypto_tfm *tfm)
311{
312 const struct crypto_type *type = tfm->__crt_alg->cra_type;
313
314 if (type && tfm->exit)
315 tfm->exit(tfm);
316}
317
318static 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
343void 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}
349EXPORT_SYMBOL_GPL(crypto_shoot_alg);
350
351struct 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
374cra_init_failed:
375 crypto_exit_ops(tfm);
376out_free_tfm:
377 if (err == -EAGAIN)
378 crypto_shoot_alg(alg);
379 kfree(tfm);
380out_err:
381 tfm = ERR_PTR(err);
382out:
383 return tfm;
384}
385EXPORT_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 * Please 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 */
409struct 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
430err:
431 if (err != -EAGAIN)
432 break;
433 if (fatal_signal_pending(current)) {
434 err = -EINTR;
435 break;
436 }
437 }
438
439 return ERR_PTR(err);
440}
441EXPORT_SYMBOL_GPL(crypto_alloc_base);
442
443void *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
471cra_init_failed:
472 crypto_exit_ops(tfm);
473out_free_tfm:
474 if (err == -EAGAIN)
475 crypto_shoot_alg(alg);
476 kfree(mem);
477out_err:
478 mem = ERR_PTR(err);
479out:
480 return mem;
481}
482EXPORT_SYMBOL_GPL(crypto_create_tfm);
483
484struct 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}
503EXPORT_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 */
525void *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
547err:
548 if (err != -EAGAIN)
549 break;
550 if (fatal_signal_pending(current)) {
551 err = -EINTR;
552 break;
553 }
554 }
555
556 return ERR_PTR(err);
557}
558EXPORT_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 */
568void 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}
583EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
584
585int 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}
597EXPORT_SYMBOL_GPL(crypto_has_alg);
598
599void crypto_req_done(struct crypto_async_request *req, int err)
600{
601 struct crypto_wait *wait = req->data;
602
603 if (err == -EINPROGRESS)
604 return;
605
606 wait->err = err;
607 complete(&wait->completion);
608}
609EXPORT_SYMBOL_GPL(crypto_req_done);
610
611MODULE_DESCRIPTION("Cryptographic core API");
612MODULE_LICENSE("GPL");