xref: /linux/crypto/api.c (revision d639d9fa162aadec1ae9980c4dcf6e50bd2f8290) 
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/jump_label.h>
16 #include <linux/kernel.h>
17 #include <linux/kmod.h>
18 #include <linux/module.h>
19 #include <linux/param.h>
20 #include <linux/sched/signal.h>
21 #include <linux/slab.h>
22 #include <linux/string.h>
23 #include <linux/completion.h>
24 #include "internal.h"
25 
26 LIST_HEAD(crypto_alg_list);
27 EXPORT_SYMBOL_GPL(crypto_alg_list);
28 DECLARE_RWSEM(crypto_alg_sem);
29 EXPORT_SYMBOL_GPL(crypto_alg_sem);
30 
31 BLOCKING_NOTIFIER_HEAD(crypto_chain);
32 EXPORT_SYMBOL_GPL(crypto_chain);
33 
34 #if IS_BUILTIN(CONFIG_CRYPTO_ALGAPI) && IS_ENABLED(CONFIG_CRYPTO_SELFTESTS)
35 DEFINE_STATIC_KEY_FALSE(__crypto_boot_test_finished);
36 #endif
37 
38 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg,
39 					     u32 type, u32 mask);
40 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
41 					    u32 mask);
42 
43 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
44 {
45 	return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
46 }
47 EXPORT_SYMBOL_GPL(crypto_mod_get);
48 
49 void crypto_mod_put(struct crypto_alg *alg)
50 {
51 	struct module *module = alg->cra_module;
52 
53 	crypto_alg_put(alg);
54 	module_put(module);
55 }
56 EXPORT_SYMBOL_GPL(crypto_mod_put);
57 
58 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
59 					      u32 mask)
60 	__must_hold_shared(&crypto_alg_sem)
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 		exact = !strcmp(q->cra_driver_name, name);
75 		fuzzy = !strcmp(q->cra_name, name);
76 		if (!exact && !(fuzzy && q->cra_priority > best))
77 			continue;
78 
79 		if (unlikely(!crypto_mod_get(q)))
80 			continue;
81 
82 		best = q->cra_priority;
83 		if (alg)
84 			crypto_mod_put(alg);
85 		alg = q;
86 
87 		if (exact)
88 			break;
89 	}
90 
91 	return alg;
92 }
93 
94 static void crypto_larval_destroy(struct crypto_alg *alg)
95 {
96 	struct crypto_larval *larval = (void *)alg;
97 
98 	BUG_ON(!crypto_is_larval(alg));
99 	if (!IS_ERR_OR_NULL(larval->adult))
100 		crypto_mod_put(larval->adult);
101 	kfree(larval);
102 }
103 
104 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
105 {
106 	struct crypto_larval *larval;
107 
108 	larval = kzalloc_obj(*larval);
109 	if (!larval)
110 		return ERR_PTR(-ENOMEM);
111 
112 	type &= ~CRYPTO_ALG_TYPE_MASK | (mask ?: CRYPTO_ALG_TYPE_MASK);
113 
114 	larval->mask = mask;
115 	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
116 	larval->alg.cra_priority = -1;
117 	larval->alg.cra_destroy = crypto_larval_destroy;
118 
119 	strscpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
120 	init_completion(&larval->completion);
121 
122 	return larval;
123 }
124 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
125 
126 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
127 					    u32 mask)
128 {
129 	struct crypto_alg *alg;
130 	struct crypto_larval *larval;
131 
132 	larval = crypto_larval_alloc(name, type, mask);
133 	if (IS_ERR(larval))
134 		return ERR_CAST(larval);
135 
136 	refcount_set(&larval->alg.cra_refcnt, 2);
137 
138 	down_write(&crypto_alg_sem);
139 	alg = __crypto_alg_lookup(name, type, mask);
140 	if (!alg) {
141 		alg = &larval->alg;
142 		list_add(&alg->cra_list, &crypto_alg_list);
143 	}
144 	up_write(&crypto_alg_sem);
145 
146 	if (alg != &larval->alg) {
147 		kfree(larval);
148 		if (crypto_is_larval(alg))
149 			alg = crypto_larval_wait(alg, type, mask);
150 	}
151 
152 	return alg;
153 }
154 
155 static void crypto_larval_kill(struct crypto_larval *larval)
156 {
157 	bool unlinked;
158 
159 	down_write(&crypto_alg_sem);
160 	unlinked = list_empty(&larval->alg.cra_list);
161 	if (!unlinked)
162 		list_del_init(&larval->alg.cra_list);
163 	up_write(&crypto_alg_sem);
164 
165 	if (unlinked)
166 		return;
167 
168 	complete_all(&larval->completion);
169 	crypto_alg_put(&larval->alg);
170 }
171 
172 void crypto_schedule_test(struct crypto_larval *larval)
173 {
174 	int err;
175 
176 	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);
177 	WARN_ON_ONCE(err != NOTIFY_STOP);
178 }
179 EXPORT_SYMBOL_GPL(crypto_schedule_test);
180 
181 static void crypto_start_test(struct crypto_larval *larval)
182 {
183 	if (!crypto_is_test_larval(larval))
184 		return;
185 
186 	if (larval->test_started)
187 		return;
188 
189 	down_write(&crypto_alg_sem);
190 	if (larval->test_started) {
191 		up_write(&crypto_alg_sem);
192 		return;
193 	}
194 
195 	larval->test_started = true;
196 	up_write(&crypto_alg_sem);
197 
198 	crypto_schedule_test(larval);
199 }
200 
201 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg,
202 					     u32 type, u32 mask)
203 {
204 	struct crypto_larval *larval;
205 	long time_left;
206 
207 again:
208 	larval = container_of(alg, struct crypto_larval, alg);
209 
210 	if (!crypto_boot_test_finished())
211 		crypto_start_test(larval);
212 
213 	time_left = wait_for_completion_killable_timeout(
214 		&larval->completion, 60 * HZ);
215 
216 	alg = larval->adult;
217 	if (time_left < 0)
218 		alg = ERR_PTR(-EINTR);
219 	else if (!time_left) {
220 		if (crypto_is_test_larval(larval))
221 			crypto_larval_kill(larval);
222 		alg = ERR_PTR(-ETIMEDOUT);
223 	} else if (!alg || PTR_ERR(alg) == -EEXIST) {
224 		int err = alg ? -EEXIST : -EAGAIN;
225 
226 		/*
227 		 * EEXIST is expected because two probes can be scheduled
228 		 * at the same time with one using alg_name and the other
229 		 * using driver_name.  Do a re-lookup but do not retry in
230 		 * case we hit a quirk like gcm_base(ctr(aes),...) which
231 		 * will never match.
232 		 */
233 		alg = &larval->alg;
234 		alg = crypto_alg_lookup(alg->cra_name, type, mask) ?:
235 		      ERR_PTR(err);
236 	} else if (IS_ERR(alg))
237 		;
238 	else if (crypto_is_test_larval(larval) &&
239 		 !(alg->cra_flags & CRYPTO_ALG_TESTED))
240 		alg = ERR_PTR(-EAGAIN);
241 	else if (alg->cra_flags & CRYPTO_ALG_FIPS_INTERNAL)
242 		alg = ERR_PTR(-EAGAIN);
243 	else if (!crypto_mod_get(alg))
244 		alg = ERR_PTR(-EAGAIN);
245 	crypto_mod_put(&larval->alg);
246 
247 	if (!IS_ERR(alg) && crypto_is_larval(alg))
248 		goto again;
249 
250 	return alg;
251 }
252 
253 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
254 					    u32 mask)
255 {
256 	const u32 fips = CRYPTO_ALG_FIPS_INTERNAL;
257 	struct crypto_alg *alg;
258 	u32 test = 0;
259 
260 	if (!((type | mask) & CRYPTO_ALG_TESTED))
261 		test |= CRYPTO_ALG_TESTED;
262 
263 	down_read(&crypto_alg_sem);
264 	alg = __crypto_alg_lookup(name, (type | test) & ~fips,
265 				  (mask | test) & ~fips);
266 	if (alg) {
267 		if (((type | mask) ^ fips) & fips)
268 			mask |= fips;
269 		mask &= fips;
270 
271 		if (!crypto_is_larval(alg) &&
272 		    ((type ^ alg->cra_flags) & mask)) {
273 			/* Algorithm is disallowed in FIPS mode. */
274 			crypto_mod_put(alg);
275 			alg = ERR_PTR(-ENOENT);
276 		}
277 	} else if (test) {
278 		alg = __crypto_alg_lookup(name, type, mask);
279 		if (alg && !crypto_is_larval(alg)) {
280 			/* Test failed */
281 			crypto_mod_put(alg);
282 			alg = ERR_PTR(-ELIBBAD);
283 		}
284 	}
285 	up_read(&crypto_alg_sem);
286 
287 	return alg;
288 }
289 
290 static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
291 					       u32 mask)
292 {
293 	struct crypto_alg *alg;
294 
295 	if (!name)
296 		return ERR_PTR(-ENOENT);
297 
298 	type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
299 	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
300 
301 	alg = crypto_alg_lookup(name, type, mask);
302 	if (!alg && !(mask & CRYPTO_NOLOAD)) {
303 		request_module("crypto-%s", name);
304 
305 		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
306 		      CRYPTO_ALG_NEED_FALLBACK))
307 			request_module("crypto-%s-all", name);
308 
309 		alg = crypto_alg_lookup(name, type, mask);
310 	}
311 
312 	if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
313 		alg = crypto_larval_wait(alg, type, mask);
314 	else if (alg)
315 		;
316 	else if (!(mask & CRYPTO_ALG_TESTED))
317 		alg = crypto_larval_add(name, type, mask);
318 	else
319 		alg = ERR_PTR(-ENOENT);
320 
321 	return alg;
322 }
323 
324 int crypto_probing_notify(unsigned long val, void *v)
325 {
326 	int ok;
327 
328 	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
329 	if (ok == NOTIFY_DONE) {
330 		request_module("cryptomgr");
331 		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
332 	}
333 
334 	return ok;
335 }
336 EXPORT_SYMBOL_GPL(crypto_probing_notify);
337 
338 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
339 {
340 	struct crypto_alg *alg;
341 	struct crypto_alg *larval;
342 	int ok;
343 
344 	/*
345 	 * If the internal flag is set for a cipher, require a caller to
346 	 * invoke the cipher with the internal flag to use that cipher.
347 	 * Also, if a caller wants to allocate a cipher that may or may
348 	 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
349 	 * !(mask & CRYPTO_ALG_INTERNAL).
350 	 */
351 	if (!((type | mask) & CRYPTO_ALG_INTERNAL))
352 		mask |= CRYPTO_ALG_INTERNAL;
353 
354 	larval = crypto_larval_lookup(name, type, mask);
355 	if (IS_ERR(larval) || !crypto_is_larval(larval))
356 		return larval;
357 
358 	ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
359 
360 	if (ok == NOTIFY_STOP)
361 		alg = crypto_larval_wait(larval, type, mask);
362 	else {
363 		crypto_mod_put(larval);
364 		alg = ERR_PTR(-ENOENT);
365 	}
366 	crypto_larval_kill(container_of(larval, struct crypto_larval, alg));
367 	return alg;
368 }
369 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
370 
371 static void crypto_exit_ops(struct crypto_tfm *tfm)
372 {
373 	const struct crypto_type *type = tfm->__crt_alg->cra_type;
374 
375 	if (type && tfm->exit)
376 		tfm->exit(tfm);
377 }
378 
379 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
380 {
381 	const struct crypto_type *type_obj = alg->cra_type;
382 	unsigned int len;
383 
384 	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
385 	if (type_obj)
386 		return len + type_obj->ctxsize(alg, type, mask);
387 
388 	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
389 	default:
390 		BUG();
391 
392 	case CRYPTO_ALG_TYPE_CIPHER:
393 		len += crypto_cipher_ctxsize(alg);
394 		break;
395 	}
396 
397 	return len;
398 }
399 
400 void crypto_shoot_alg(struct crypto_alg *alg)
401 {
402 	down_write(&crypto_alg_sem);
403 	alg->cra_flags |= CRYPTO_ALG_DYING;
404 	up_write(&crypto_alg_sem);
405 }
406 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
407 
408 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
409 				      u32 mask)
410 {
411 	struct crypto_tfm *tfm;
412 	unsigned int tfm_size;
413 	int err = -ENOMEM;
414 
415 	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
416 	tfm = kzalloc(tfm_size, GFP_KERNEL);
417 	if (tfm == NULL)
418 		goto out_err;
419 
420 	tfm->__crt_alg = alg;
421 
422 	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
423 		goto cra_init_failed;
424 
425 	goto out;
426 
427 cra_init_failed:
428 	crypto_exit_ops(tfm);
429 	if (err == -EAGAIN)
430 		crypto_shoot_alg(alg);
431 	kfree(tfm);
432 out_err:
433 	tfm = ERR_PTR(err);
434 out:
435 	return tfm;
436 }
437 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
438 
439 /*
440  *	crypto_alloc_base - Locate algorithm and allocate transform
441  *	@alg_name: Name of algorithm
442  *	@type: Type of algorithm
443  *	@mask: Mask for type comparison
444  *
445  *	This function should not be used by new algorithm types.
446  *	Please use crypto_alloc_tfm instead.
447  *
448  *	crypto_alloc_base() will first attempt to locate an already loaded
449  *	algorithm.  If that fails and the kernel supports dynamically loadable
450  *	modules, it will then attempt to load a module of the same name or
451  *	alias.  If that fails it will send a query to any loaded crypto manager
452  *	to construct an algorithm on the fly.  A refcount is grabbed on the
453  *	algorithm which is then associated with the new transform.
454  *
455  *	The returned transform is of a non-determinate type.  Most people
456  *	should use one of the more specific allocation functions such as
457  *	crypto_alloc_skcipher().
458  *
459  *	In case of error the return value is an error pointer.
460  */
461 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
462 {
463 	struct crypto_tfm *tfm;
464 	int err;
465 
466 	for (;;) {
467 		struct crypto_alg *alg;
468 
469 		alg = crypto_alg_mod_lookup(alg_name, type, mask);
470 		if (IS_ERR(alg)) {
471 			err = PTR_ERR(alg);
472 			goto err;
473 		}
474 
475 		tfm = __crypto_alloc_tfm(alg, type, mask);
476 		if (!IS_ERR(tfm))
477 			return tfm;
478 
479 		crypto_mod_put(alg);
480 		err = PTR_ERR(tfm);
481 
482 err:
483 		if (err != -EAGAIN)
484 			break;
485 		if (fatal_signal_pending(current)) {
486 			err = -EINTR;
487 			break;
488 		}
489 	}
490 
491 	return ERR_PTR(err);
492 }
493 EXPORT_SYMBOL_GPL(crypto_alloc_base);
494 
495 void *crypto_create_tfm_node(struct crypto_alg *alg,
496 			     const struct crypto_type *frontend,
497 			     int node)
498 {
499 	struct crypto_tfm *tfm;
500 	size_t size;
501 	char *mem;
502 	int err;
503 
504 	size = frontend->tfmsize + sizeof(*tfm) + frontend->extsize(alg);
505 	mem = kzalloc_node(size, GFP_KERNEL, node);
506 	if (!mem)
507 		return ERR_PTR(-ENOMEM);
508 
509 	tfm = (struct crypto_tfm *)(mem + frontend->tfmsize);
510 	tfm->__crt_alg = alg;
511 	tfm->node = node;
512 	tfm->fb = tfm;
513 
514 	err = frontend->init_tfm(tfm);
515 	if (err)
516 		goto out_free_tfm;
517 
518 	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
519 		goto cra_init_failed;
520 
521 	goto out;
522 
523 cra_init_failed:
524 	crypto_exit_ops(tfm);
525 out_free_tfm:
526 	if (err == -EAGAIN)
527 		crypto_shoot_alg(alg);
528 	kfree(mem);
529 	mem = ERR_PTR(err);
530 out:
531 	return mem;
532 }
533 EXPORT_SYMBOL_GPL(crypto_create_tfm_node);
534 
535 struct crypto_alg *crypto_find_alg(const char *alg_name,
536 				   const struct crypto_type *frontend,
537 				   u32 type, u32 mask)
538 {
539 	if (frontend) {
540 		type &= frontend->maskclear;
541 		mask &= frontend->maskclear;
542 		type |= frontend->type;
543 		mask |= frontend->maskset;
544 	}
545 
546 	return crypto_alg_mod_lookup(alg_name, type, mask);
547 }
548 EXPORT_SYMBOL_GPL(crypto_find_alg);
549 
550 /*
551  *	crypto_alloc_tfm_node - Locate algorithm and allocate transform
552  *	@alg_name: Name of algorithm
553  *	@frontend: Frontend algorithm type
554  *	@type: Type of algorithm
555  *	@mask: Mask for type comparison
556  *	@node: NUMA node in which users desire to put requests, if node is
557  *		NUMA_NO_NODE, it means users have no special requirement.
558  *
559  *	crypto_alloc_tfm() will first attempt to locate an already loaded
560  *	algorithm.  If that fails and the kernel supports dynamically loadable
561  *	modules, it will then attempt to load a module of the same name or
562  *	alias.  If that fails it will send a query to any loaded crypto manager
563  *	to construct an algorithm on the fly.  A refcount is grabbed on the
564  *	algorithm which is then associated with the new transform.
565  *
566  *	The returned transform is of a non-determinate type.  Most people
567  *	should use one of the more specific allocation functions such as
568  *	crypto_alloc_skcipher().
569  *
570  *	In case of error the return value is an error pointer.
571  */
572 
573 void *crypto_alloc_tfm_node(const char *alg_name,
574 		       const struct crypto_type *frontend, u32 type, u32 mask,
575 		       int node)
576 {
577 	void *tfm;
578 	int err;
579 
580 	for (;;) {
581 		struct crypto_alg *alg;
582 
583 		alg = crypto_find_alg(alg_name, frontend, type, mask);
584 		if (IS_ERR(alg)) {
585 			err = PTR_ERR(alg);
586 			goto err;
587 		}
588 
589 		tfm = crypto_create_tfm_node(alg, frontend, node);
590 		if (!IS_ERR(tfm))
591 			return tfm;
592 
593 		crypto_mod_put(alg);
594 		err = PTR_ERR(tfm);
595 
596 err:
597 		if (err != -EAGAIN)
598 			break;
599 		if (fatal_signal_pending(current)) {
600 			err = -EINTR;
601 			break;
602 		}
603 	}
604 
605 	return ERR_PTR(err);
606 }
607 EXPORT_SYMBOL_GPL(crypto_alloc_tfm_node);
608 
609 /*
610  *	crypto_destroy_tfm - Free crypto transform
611  *	@mem: Start of tfm slab
612  *	@tfm: Transform to free
613  *
614  *	This function frees up the transform and any associated resources,
615  *	then drops the refcount on the associated algorithm.
616  */
617 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
618 {
619 	struct crypto_alg *alg;
620 
621 	if (IS_ERR_OR_NULL(mem))
622 		return;
623 
624 	alg = tfm->__crt_alg;
625 
626 	if (!tfm->exit && alg->cra_exit)
627 		alg->cra_exit(tfm);
628 	crypto_exit_ops(tfm);
629 	crypto_mod_put(alg);
630 	kfree_sensitive(mem);
631 }
632 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
633 
634 int crypto_has_alg(const char *name, u32 type, u32 mask)
635 {
636 	int ret = 0;
637 	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
638 
639 	if (!IS_ERR(alg)) {
640 		crypto_mod_put(alg);
641 		ret = 1;
642 	}
643 
644 	return ret;
645 }
646 EXPORT_SYMBOL_GPL(crypto_has_alg);
647 
648 void crypto_req_done(void *data, int err)
649 {
650 	struct crypto_wait *wait = data;
651 
652 	if (err == -EINPROGRESS)
653 		return;
654 
655 	wait->err = err;
656 	complete(&wait->completion);
657 }
658 EXPORT_SYMBOL_GPL(crypto_req_done);
659 
660 void crypto_destroy_alg(struct crypto_alg *alg)
661 {
662 	if (alg->cra_type && alg->cra_type->destroy)
663 		alg->cra_type->destroy(alg);
664 	if (alg->cra_destroy)
665 		alg->cra_destroy(alg);
666 }
667 EXPORT_SYMBOL_GPL(crypto_destroy_alg);
668 
669 struct crypto_async_request *crypto_request_clone(
670 	struct crypto_async_request *req, size_t total, gfp_t gfp)
671 {
672 	struct crypto_tfm *tfm = req->tfm;
673 	struct crypto_async_request *nreq;
674 
675 	nreq = kmemdup(req, total, gfp);
676 	if (!nreq) {
677 		req->tfm = tfm->fb;
678 		return req;
679 	}
680 
681 	nreq->flags &= ~CRYPTO_TFM_REQ_ON_STACK;
682 	return nreq;
683 }
684 EXPORT_SYMBOL_GPL(crypto_request_clone);
685 
686 MODULE_DESCRIPTION("Cryptographic core API");
687 MODULE_LICENSE("GPL");
688