1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Scatterlist Cryptographic API.
4 *
5 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
6 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
7 * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
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
25 LIST_HEAD(crypto_alg_list);
26 EXPORT_SYMBOL_GPL(crypto_alg_list);
27 DECLARE_RWSEM(crypto_alg_sem);
28 EXPORT_SYMBOL_GPL(crypto_alg_sem);
29
30 BLOCKING_NOTIFIER_HEAD(crypto_chain);
31 EXPORT_SYMBOL_GPL(crypto_chain);
32
33 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
34
crypto_mod_get(struct crypto_alg * alg)35 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
36 {
37 return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
38 }
39 EXPORT_SYMBOL_GPL(crypto_mod_get);
40
crypto_mod_put(struct crypto_alg * alg)41 void 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 }
48 EXPORT_SYMBOL_GPL(crypto_mod_put);
49
crypto_is_test_larval(struct crypto_larval * larval)50 static inline int crypto_is_test_larval(struct crypto_larval *larval)
51 {
52 return larval->alg.cra_driver_name[0];
53 }
54
__crypto_alg_lookup(const char * name,u32 type,u32 mask)55 static 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
crypto_larval_destroy(struct crypto_alg * alg)95 static 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 (!IS_ERR_OR_NULL(larval->adult))
101 crypto_mod_put(larval->adult);
102 kfree(larval);
103 }
104
crypto_larval_alloc(const char * name,u32 type,u32 mask)105 struct 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 }
123 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
124
crypto_larval_add(const char * name,u32 type,u32 mask)125 static 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
crypto_larval_kill(struct crypto_alg * alg)154 void 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 }
164 EXPORT_SYMBOL_GPL(crypto_larval_kill);
165
crypto_larval_wait(struct crypto_alg * alg)166 static 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 (IS_ERR(alg))
182 ;
183 else if (crypto_is_test_larval(larval) &&
184 !(alg->cra_flags & CRYPTO_ALG_TESTED))
185 alg = ERR_PTR(-EAGAIN);
186 else if (!crypto_mod_get(alg))
187 alg = ERR_PTR(-EAGAIN);
188 crypto_mod_put(&larval->alg);
189
190 return alg;
191 }
192
crypto_alg_lookup(const char * name,u32 type,u32 mask)193 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
194 u32 mask)
195 {
196 struct crypto_alg *alg;
197 u32 test = 0;
198
199 if (!((type | mask) & CRYPTO_ALG_TESTED))
200 test |= CRYPTO_ALG_TESTED;
201
202 down_read(&crypto_alg_sem);
203 alg = __crypto_alg_lookup(name, type | test, mask | test);
204 if (!alg && test) {
205 alg = __crypto_alg_lookup(name, type, mask);
206 if (alg && !crypto_is_larval(alg)) {
207 /* Test failed */
208 crypto_mod_put(alg);
209 alg = ERR_PTR(-ELIBBAD);
210 }
211 }
212 up_read(&crypto_alg_sem);
213
214 return alg;
215 }
216
crypto_larval_lookup(const char * name,u32 type,u32 mask)217 static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
218 u32 mask)
219 {
220 struct crypto_alg *alg;
221
222 if (!name)
223 return ERR_PTR(-ENOENT);
224
225 type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
226 mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
227
228 alg = crypto_alg_lookup(name, type, mask);
229 if (!alg && !(mask & CRYPTO_NOLOAD)) {
230 request_module("crypto-%s", name);
231
232 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
233 CRYPTO_ALG_NEED_FALLBACK))
234 request_module("crypto-%s-all", name);
235
236 alg = crypto_alg_lookup(name, type, mask);
237 }
238
239 if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
240 alg = crypto_larval_wait(alg);
241 else if (!alg)
242 alg = crypto_larval_add(name, type, mask);
243
244 return alg;
245 }
246
crypto_probing_notify(unsigned long val,void * v)247 int crypto_probing_notify(unsigned long val, void *v)
248 {
249 int ok;
250
251 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
252 if (ok == NOTIFY_DONE) {
253 request_module("cryptomgr");
254 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
255 }
256
257 return ok;
258 }
259 EXPORT_SYMBOL_GPL(crypto_probing_notify);
260
crypto_alg_mod_lookup(const char * name,u32 type,u32 mask)261 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
262 {
263 struct crypto_alg *alg;
264 struct crypto_alg *larval;
265 int ok;
266
267 /*
268 * If the internal flag is set for a cipher, require a caller to
269 * to invoke the cipher with the internal flag to use that cipher.
270 * Also, if a caller wants to allocate a cipher that may or may
271 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
272 * !(mask & CRYPTO_ALG_INTERNAL).
273 */
274 if (!((type | mask) & CRYPTO_ALG_INTERNAL))
275 mask |= CRYPTO_ALG_INTERNAL;
276
277 larval = crypto_larval_lookup(name, type, mask);
278 if (IS_ERR(larval) || !crypto_is_larval(larval))
279 return larval;
280
281 ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
282
283 if (ok == NOTIFY_STOP)
284 alg = crypto_larval_wait(larval);
285 else {
286 crypto_mod_put(larval);
287 alg = ERR_PTR(-ENOENT);
288 }
289 crypto_larval_kill(larval);
290 return alg;
291 }
292 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
293
crypto_init_ops(struct crypto_tfm * tfm,u32 type,u32 mask)294 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
295 {
296 const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
297
298 if (type_obj)
299 return type_obj->init(tfm, type, mask);
300
301 switch (crypto_tfm_alg_type(tfm)) {
302 case CRYPTO_ALG_TYPE_CIPHER:
303 return crypto_init_cipher_ops(tfm);
304
305 case CRYPTO_ALG_TYPE_COMPRESS:
306 return crypto_init_compress_ops(tfm);
307
308 default:
309 break;
310 }
311
312 BUG();
313 return -EINVAL;
314 }
315
crypto_exit_ops(struct crypto_tfm * tfm)316 static void crypto_exit_ops(struct crypto_tfm *tfm)
317 {
318 const struct crypto_type *type = tfm->__crt_alg->cra_type;
319
320 if (type && tfm->exit)
321 tfm->exit(tfm);
322 }
323
crypto_ctxsize(struct crypto_alg * alg,u32 type,u32 mask)324 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
325 {
326 const struct crypto_type *type_obj = alg->cra_type;
327 unsigned int len;
328
329 len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
330 if (type_obj)
331 return len + type_obj->ctxsize(alg, type, mask);
332
333 switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
334 default:
335 BUG();
336
337 case CRYPTO_ALG_TYPE_CIPHER:
338 len += crypto_cipher_ctxsize(alg);
339 break;
340
341 case CRYPTO_ALG_TYPE_COMPRESS:
342 len += crypto_compress_ctxsize(alg);
343 break;
344 }
345
346 return len;
347 }
348
crypto_shoot_alg(struct crypto_alg * alg)349 static void crypto_shoot_alg(struct crypto_alg *alg)
350 {
351 down_write(&crypto_alg_sem);
352 alg->cra_flags |= CRYPTO_ALG_DYING;
353 up_write(&crypto_alg_sem);
354 }
355
__crypto_alloc_tfm(struct crypto_alg * alg,u32 type,u32 mask)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 */
crypto_alloc_base(const char * alg_name,u32 type,u32 mask)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
crypto_create_tfm(struct crypto_alg * alg,const struct crypto_type * frontend)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
crypto_find_alg(const char * alg_name,const struct crypto_type * frontend,u32 type,u32 mask)489 struct crypto_alg *crypto_find_alg(const char *alg_name,
490 const struct crypto_type *frontend,
491 u32 type, u32 mask)
492 {
493 if (frontend) {
494 type &= frontend->maskclear;
495 mask &= frontend->maskclear;
496 type |= frontend->type;
497 mask |= frontend->maskset;
498 }
499
500 return crypto_alg_mod_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 */
crypto_alloc_tfm(const char * alg_name,const struct crypto_type * frontend,u32 type,u32 mask)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 */
crypto_destroy_tfm(void * mem,struct crypto_tfm * tfm)567 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
568 {
569 struct crypto_alg *alg;
570
571 if (IS_ERR_OR_NULL(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
crypto_has_alg(const char * name,u32 type,u32 mask)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
crypto_req_done(struct crypto_async_request * req,int err)598 void crypto_req_done(struct crypto_async_request *req, int err)
599 {
600 struct crypto_wait *wait = req->data;
601
602 if (err == -EINPROGRESS)
603 return;
604
605 wait->err = err;
606 complete(&wait->completion);
607 }
608 EXPORT_SYMBOL_GPL(crypto_req_done);
609
610 MODULE_DESCRIPTION("Cryptographic core API");
611 MODULE_LICENSE("GPL");
612