projects/linux·blob v5.2 · refs

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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Scatterlist Cryptographic API.
4 *
5 * Copyright (c) 2002 James Morris <[email protected]>
6 * Copyright (c) 2002 David S. Miller ([email protected])
7 * Copyright (c) 2005 Herbert Xu <[email protected]>
8 *
9 * Portions derived from Cryptoapi, by Alexander Kjeldaas <[email protected]>
10 * and Nettle, by Niels Möller.
11 */
12
13#include <linux/err.h>
14#include <linux/errno.h>
15#include <linux/kernel.h>
16#include <linux/kmod.h>
17#include <linux/module.h>
18#include <linux/param.h>
19#include <linux/sched/signal.h>
20#include <linux/slab.h>
21#include <linux/string.h>
22#include <linux/completion.h>
23#include "internal.h"
24
25LIST_HEAD(crypto_alg_list);
26EXPORT_SYMBOL_GPL(crypto_alg_list);
27DECLARE_RWSEM(crypto_alg_sem);
28EXPORT_SYMBOL_GPL(crypto_alg_sem);
29
30BLOCKING_NOTIFIER_HEAD(crypto_chain);
31EXPORT_SYMBOL_GPL(crypto_chain);
32
33static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
34
35struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
36{
37 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
38}
39EXPORT_SYMBOL_GPL(crypto_mod_get);
40
41void crypto_mod_put(struct crypto_alg *alg)
42{
43 struct module *module = alg->cra_module;
44
45 crypto_alg_put(alg);
46 module_put(module);
47}
48EXPORT_SYMBOL_GPL(crypto_mod_put);
49
50static inline int crypto_is_test_larval(struct crypto_larval *larval)
51{
52 return larval->alg.cra_driver_name[0];
53}
54
55static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
56 u32 mask)
57{
58 struct crypto_alg *q, *alg = NULL;
59 int best = -2;
60
61 list_for_each_entry(q, &crypto_alg_list, cra_list) {
62 int exact, fuzzy;
63
64 if (crypto_is_moribund(q))
65 continue;
66
67 if ((q->cra_flags ^ type) & mask)
68 continue;
69
70 if (crypto_is_larval(q) &&
71 !crypto_is_test_larval((struct crypto_larval *)q) &&
72 ((struct crypto_larval *)q)->mask != mask)
73 continue;
74
75 exact = !strcmp(q->cra_driver_name, name);
76 fuzzy = !strcmp(q->cra_name, name);
77 if (!exact && !(fuzzy && q->cra_priority > best))
78 continue;
79
80 if (unlikely(!crypto_mod_get(q)))
81 continue;
82
83 best = q->cra_priority;
84 if (alg)
85 crypto_mod_put(alg);
86 alg = q;
87
88 if (exact)
89 break;
90 }
91
92 return alg;
93}
94
95static void crypto_larval_destroy(struct crypto_alg *alg)
96{
97 struct crypto_larval *larval = (void *)alg;
98
99 BUG_ON(!crypto_is_larval(alg));
100 if (larval->adult)
101 crypto_mod_put(larval->adult);
102 kfree(larval);
103}
104
105struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
106{
107 struct crypto_larval *larval;
108
109 larval = kzalloc(sizeof(*larval), GFP_KERNEL);
110 if (!larval)
111 return ERR_PTR(-ENOMEM);
112
113 larval->mask = mask;
114 larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
115 larval->alg.cra_priority = -1;
116 larval->alg.cra_destroy = crypto_larval_destroy;
117
118 strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
119 init_completion(&larval->completion);
120
121 return larval;
122}
123EXPORT_SYMBOL_GPL(crypto_larval_alloc);
124
125static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
126 u32 mask)
127{
128 struct crypto_alg *alg;
129 struct crypto_larval *larval;
130
131 larval = crypto_larval_alloc(name, type, mask);
132 if (IS_ERR(larval))
133 return ERR_CAST(larval);
134
135 refcount_set(&larval->alg.cra_refcnt, 2);
136
137 down_write(&crypto_alg_sem);
138 alg = __crypto_alg_lookup(name, type, mask);
139 if (!alg) {
140 alg = &larval->alg;
141 list_add(&alg->cra_list, &crypto_alg_list);
142 }
143 up_write(&crypto_alg_sem);
144
145 if (alg != &larval->alg) {
146 kfree(larval);
147 if (crypto_is_larval(alg))
148 alg = crypto_larval_wait(alg);
149 }
150
151 return alg;
152}
153
154void crypto_larval_kill(struct crypto_alg *alg)
155{
156 struct crypto_larval *larval = (void *)alg;
157
158 down_write(&crypto_alg_sem);
159 list_del(&alg->cra_list);
160 up_write(&crypto_alg_sem);
161 complete_all(&larval->completion);
162 crypto_alg_put(alg);
163}
164EXPORT_SYMBOL_GPL(crypto_larval_kill);
165
166static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
167{
168 struct crypto_larval *larval = (void *)alg;
169 long timeout;
170
171 timeout = wait_for_completion_killable_timeout(
172 &larval->completion, 60 * HZ);
173
174 alg = larval->adult;
175 if (timeout < 0)
176 alg = ERR_PTR(-EINTR);
177 else if (!timeout)
178 alg = ERR_PTR(-ETIMEDOUT);
179 else if (!alg)
180 alg = ERR_PTR(-ENOENT);
181 else if (crypto_is_test_larval(larval) &&
182 !(alg->cra_flags & CRYPTO_ALG_TESTED))
183 alg = ERR_PTR(-EAGAIN);
184 else if (!crypto_mod_get(alg))
185 alg = ERR_PTR(-EAGAIN);
186 crypto_mod_put(&larval->alg);
187
188 return alg;
189}
190
191static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
192 u32 mask)
193{
194 struct crypto_alg *alg;
195 u32 test = 0;
196
197 if (!((type | mask) & CRYPTO_ALG_TESTED))
198 test |= CRYPTO_ALG_TESTED;
199
200 down_read(&crypto_alg_sem);
201 alg = __crypto_alg_lookup(name, type | test, mask | test);
202 if (!alg && test) {
203 alg = __crypto_alg_lookup(name, type, mask);
204 if (alg && !crypto_is_larval(alg)) {
205 /* Test failed */
206 crypto_mod_put(alg);
207 alg = ERR_PTR(-ELIBBAD);
208 }
209 }
210 up_read(&crypto_alg_sem);
211
212 return alg;
213}
214
215static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
216 u32 mask)
217{
218 struct crypto_alg *alg;
219
220 if (!name)
221 return ERR_PTR(-ENOENT);
222
223 type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
224 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
225
226 alg = crypto_alg_lookup(name, type, mask);
227 if (!alg && !(mask & CRYPTO_NOLOAD)) {
228 request_module("crypto-%s", name);
229
230 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
231 CRYPTO_ALG_NEED_FALLBACK))
232 request_module("crypto-%s-all", name);
233
234 alg = crypto_alg_lookup(name, type, mask);
235 }
236
237 if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
238 alg = crypto_larval_wait(alg);
239 else if (!alg)
240 alg = crypto_larval_add(name, type, mask);
241
242 return alg;
243}
244
245int crypto_probing_notify(unsigned long val, void *v)
246{
247 int ok;
248
249 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
250 if (ok == NOTIFY_DONE) {
251 request_module("cryptomgr");
252 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
253 }
254
255 return ok;
256}
257EXPORT_SYMBOL_GPL(crypto_probing_notify);
258
259struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
260{
261 struct crypto_alg *alg;
262 struct crypto_alg *larval;
263 int ok;
264
265 /*
266 * If the internal flag is set for a cipher, require a caller to
267 * to invoke the cipher with the internal flag to use that cipher.
268 * Also, if a caller wants to allocate a cipher that may or may
269 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
270 * !(mask & CRYPTO_ALG_INTERNAL).
271 */
272 if (!((type | mask) & CRYPTO_ALG_INTERNAL))
273 mask |= CRYPTO_ALG_INTERNAL;
274
275 larval = crypto_larval_lookup(name, type, mask);
276 if (IS_ERR(larval) || !crypto_is_larval(larval))
277 return larval;
278
279 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
280
281 if (ok == NOTIFY_STOP)
282 alg = crypto_larval_wait(larval);
283 else {
284 crypto_mod_put(larval);
285 alg = ERR_PTR(-ENOENT);
286 }
287 crypto_larval_kill(larval);
288 return alg;
289}
290EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
291
292static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
293{
294 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
295
296 if (type_obj)
297 return type_obj->init(tfm, type, mask);
298
299 switch (crypto_tfm_alg_type(tfm)) {
300 case CRYPTO_ALG_TYPE_CIPHER:
301 return crypto_init_cipher_ops(tfm);
302
303 case CRYPTO_ALG_TYPE_COMPRESS:
304 return crypto_init_compress_ops(tfm);
305
306 default:
307 break;
308 }
309
310 BUG();
311 return -EINVAL;
312}
313
314static void crypto_exit_ops(struct crypto_tfm *tfm)
315{
316 const struct crypto_type *type = tfm->__crt_alg->cra_type;
317
318 if (type && tfm->exit)
319 tfm->exit(tfm);
320}
321
322static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
323{
324 const struct crypto_type *type_obj = alg->cra_type;
325 unsigned int len;
326
327 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
328 if (type_obj)
329 return len + type_obj->ctxsize(alg, type, mask);
330
331 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
332 default:
333 BUG();
334
335 case CRYPTO_ALG_TYPE_CIPHER:
336 len += crypto_cipher_ctxsize(alg);
337 break;
338
339 case CRYPTO_ALG_TYPE_COMPRESS:
340 len += crypto_compress_ctxsize(alg);
341 break;
342 }
343
344 return len;
345}
346
347void crypto_shoot_alg(struct crypto_alg *alg)
348{
349 down_write(&crypto_alg_sem);
350 alg->cra_flags |= CRYPTO_ALG_DYING;
351 up_write(&crypto_alg_sem);
352}
353EXPORT_SYMBOL_GPL(crypto_shoot_alg);
354
355struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
356 u32 mask)
357{
358 struct crypto_tfm *tfm = NULL;
359 unsigned int tfm_size;
360 int err = -ENOMEM;
361
362 tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
363 tfm = kzalloc(tfm_size, GFP_KERNEL);
364 if (tfm == NULL)
365 goto out_err;
366
367 tfm->__crt_alg = alg;
368
369 err = crypto_init_ops(tfm, type, mask);
370 if (err)
371 goto out_free_tfm;
372
373 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
374 goto cra_init_failed;
375
376 goto out;
377
378cra_init_failed:
379 crypto_exit_ops(tfm);
380out_free_tfm:
381 if (err == -EAGAIN)
382 crypto_shoot_alg(alg);
383 kfree(tfm);
384out_err:
385 tfm = ERR_PTR(err);
386out:
387 return tfm;
388}
389EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
390
391/*
392 * crypto_alloc_base - Locate algorithm and allocate transform
393 * @alg_name: Name of algorithm
394 * @type: Type of algorithm
395 * @mask: Mask for type comparison
396 *
397 * This function should not be used by new algorithm types.
398 * Please use crypto_alloc_tfm instead.
399 *
400 * crypto_alloc_base() will first attempt to locate an already loaded
401 * algorithm. If that fails and the kernel supports dynamically loadable
402 * modules, it will then attempt to load a module of the same name or
403 * alias. If that fails it will send a query to any loaded crypto manager
404 * to construct an algorithm on the fly. A refcount is grabbed on the
405 * algorithm which is then associated with the new transform.
406 *
407 * The returned transform is of a non-determinate type. Most people
408 * should use one of the more specific allocation functions such as
409 * crypto_alloc_blkcipher.
410 *
411 * In case of error the return value is an error pointer.
412 */
413struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
414{
415 struct crypto_tfm *tfm;
416 int err;
417
418 for (;;) {
419 struct crypto_alg *alg;
420
421 alg = crypto_alg_mod_lookup(alg_name, type, mask);
422 if (IS_ERR(alg)) {
423 err = PTR_ERR(alg);
424 goto err;
425 }
426
427 tfm = __crypto_alloc_tfm(alg, type, mask);
428 if (!IS_ERR(tfm))
429 return tfm;
430
431 crypto_mod_put(alg);
432 err = PTR_ERR(tfm);
433
434err:
435 if (err != -EAGAIN)
436 break;
437 if (fatal_signal_pending(current)) {
438 err = -EINTR;
439 break;
440 }
441 }
442
443 return ERR_PTR(err);
444}
445EXPORT_SYMBOL_GPL(crypto_alloc_base);
446
447void *crypto_create_tfm(struct crypto_alg *alg,
448 const struct crypto_type *frontend)
449{
450 char *mem;
451 struct crypto_tfm *tfm = NULL;
452 unsigned int tfmsize;
453 unsigned int total;
454 int err = -ENOMEM;
455
456 tfmsize = frontend->tfmsize;
457 total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
458
459 mem = kzalloc(total, GFP_KERNEL);
460 if (mem == NULL)
461 goto out_err;
462
463 tfm = (struct crypto_tfm *)(mem + tfmsize);
464 tfm->__crt_alg = alg;
465
466 err = frontend->init_tfm(tfm);
467 if (err)
468 goto out_free_tfm;
469
470 if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
471 goto cra_init_failed;
472
473 goto out;
474
475cra_init_failed:
476 crypto_exit_ops(tfm);
477out_free_tfm:
478 if (err == -EAGAIN)
479 crypto_shoot_alg(alg);
480 kfree(mem);
481out_err:
482 mem = ERR_PTR(err);
483out:
484 return mem;
485}
486EXPORT_SYMBOL_GPL(crypto_create_tfm);
487
488struct crypto_alg *crypto_find_alg(const char *alg_name,
489 const struct crypto_type *frontend,
490 u32 type, u32 mask)
491{
492 if (frontend) {
493 type &= frontend->maskclear;
494 mask &= frontend->maskclear;
495 type |= frontend->type;
496 mask |= frontend->maskset;
497 }
498
499 return crypto_alg_mod_lookup(alg_name, type, mask);
500}
501EXPORT_SYMBOL_GPL(crypto_find_alg);
502
503/*
504 * crypto_alloc_tfm - Locate algorithm and allocate transform
505 * @alg_name: Name of algorithm
506 * @frontend: Frontend algorithm type
507 * @type: Type of algorithm
508 * @mask: Mask for type comparison
509 *
510 * crypto_alloc_tfm() will first attempt to locate an already loaded
511 * algorithm. If that fails and the kernel supports dynamically loadable
512 * modules, it will then attempt to load a module of the same name or
513 * alias. If that fails it will send a query to any loaded crypto manager
514 * to construct an algorithm on the fly. A refcount is grabbed on the
515 * algorithm which is then associated with the new transform.
516 *
517 * The returned transform is of a non-determinate type. Most people
518 * should use one of the more specific allocation functions such as
519 * crypto_alloc_blkcipher.
520 *
521 * In case of error the return value is an error pointer.
522 */
523void *crypto_alloc_tfm(const char *alg_name,
524 const struct crypto_type *frontend, u32 type, u32 mask)
525{
526 void *tfm;
527 int err;
528
529 for (;;) {
530 struct crypto_alg *alg;
531
532 alg = crypto_find_alg(alg_name, frontend, type, mask);
533 if (IS_ERR(alg)) {
534 err = PTR_ERR(alg);
535 goto err;
536 }
537
538 tfm = crypto_create_tfm(alg, frontend);
539 if (!IS_ERR(tfm))
540 return tfm;
541
542 crypto_mod_put(alg);
543 err = PTR_ERR(tfm);
544
545err:
546 if (err != -EAGAIN)
547 break;
548 if (fatal_signal_pending(current)) {
549 err = -EINTR;
550 break;
551 }
552 }
553
554 return ERR_PTR(err);
555}
556EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
557
558/*
559 * crypto_destroy_tfm - Free crypto transform
560 * @mem: Start of tfm slab
561 * @tfm: Transform to free
562 *
563 * This function frees up the transform and any associated resources,
564 * then drops the refcount on the associated algorithm.
565 */
566void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
567{
568 struct crypto_alg *alg;
569
570 if (unlikely(!mem))
571 return;
572
573 alg = tfm->__crt_alg;
574
575 if (!tfm->exit && alg->cra_exit)
576 alg->cra_exit(tfm);
577 crypto_exit_ops(tfm);
578 crypto_mod_put(alg);
579 kzfree(mem);
580}
581EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
582
583int crypto_has_alg(const char *name, u32 type, u32 mask)
584{
585 int ret = 0;
586 struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
587
588 if (!IS_ERR(alg)) {
589 crypto_mod_put(alg);
590 ret = 1;
591 }
592
593 return ret;
594}
595EXPORT_SYMBOL_GPL(crypto_has_alg);
596
597void crypto_req_done(struct crypto_async_request *req, int err)
598{
599 struct crypto_wait *wait = req->data;
600
601 if (err == -EINPROGRESS)
602 return;
603
604 wait->err = err;
605 complete(&wait->completion);
606}
607EXPORT_SYMBOL_GPL(crypto_req_done);
608
609MODULE_DESCRIPTION("Cryptographic core API");
610MODULE_LICENSE("GPL");