xref: /openbmc/linux/crypto/api.c (revision c796f021) 
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 DEFINE_STATIC_KEY_FALSE(crypto_boot_test_finished);
35 EXPORT_SYMBOL_GPL(crypto_boot_test_finished);
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 struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
55 					      u32 mask)
56 {
57 	struct crypto_alg *q, *alg = NULL;
58 	int best = -2;
59 
60 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
61 		int exact, fuzzy;
62 
63 		if (crypto_is_moribund(q))
64 			continue;
65 
66 		if ((q->cra_flags ^ type) & mask)
67 			continue;
68 
69 		if (crypto_is_larval(q) &&
70 		    !crypto_is_test_larval((struct crypto_larval *)q) &&
71 		    ((struct crypto_larval *)q)->mask != 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(sizeof(*larval), GFP_KERNEL);
109 	if (!larval)
110 		return ERR_PTR(-ENOMEM);
111 
112 	larval->mask = mask;
113 	larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
114 	larval->alg.cra_priority = -1;
115 	larval->alg.cra_destroy = crypto_larval_destroy;
116 
117 	strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
118 	init_completion(&larval->completion);
119 
120 	return larval;
121 }
122 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
123 
124 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
125 					    u32 mask)
126 {
127 	struct crypto_alg *alg;
128 	struct crypto_larval *larval;
129 
130 	larval = crypto_larval_alloc(name, type, mask);
131 	if (IS_ERR(larval))
132 		return ERR_CAST(larval);
133 
134 	refcount_set(&larval->alg.cra_refcnt, 2);
135 
136 	down_write(&crypto_alg_sem);
137 	alg = __crypto_alg_lookup(name, type, mask);
138 	if (!alg) {
139 		alg = &larval->alg;
140 		list_add(&alg->cra_list, &crypto_alg_list);
141 	}
142 	up_write(&crypto_alg_sem);
143 
144 	if (alg != &larval->alg) {
145 		kfree(larval);
146 		if (crypto_is_larval(alg))
147 			alg = crypto_larval_wait(alg);
148 	}
149 
150 	return alg;
151 }
152 
153 void crypto_larval_kill(struct crypto_alg *alg)
154 {
155 	struct crypto_larval *larval = (void *)alg;
156 
157 	down_write(&crypto_alg_sem);
158 	list_del(&alg->cra_list);
159 	up_write(&crypto_alg_sem);
160 	complete_all(&larval->completion);
161 	crypto_alg_put(alg);
162 }
163 EXPORT_SYMBOL_GPL(crypto_larval_kill);
164 
165 void crypto_wait_for_test(struct crypto_larval *larval)
166 {
167 	int err;
168 
169 	err = crypto_probing_notify(CRYPTO_MSG_ALG_REGISTER, larval->adult);
170 	if (WARN_ON_ONCE(err != NOTIFY_STOP))
171 		goto out;
172 
173 	err = wait_for_completion_killable(&larval->completion);
174 	WARN_ON(err);
175 	if (!err)
176 		crypto_notify(CRYPTO_MSG_ALG_LOADED, larval);
177 
178 out:
179 	crypto_larval_kill(&larval->alg);
180 }
181 EXPORT_SYMBOL_GPL(crypto_wait_for_test);
182 
183 static void crypto_start_test(struct crypto_larval *larval)
184 {
185 	if (!crypto_is_test_larval(larval))
186 		return;
187 
188 	if (larval->test_started)
189 		return;
190 
191 	down_write(&crypto_alg_sem);
192 	if (larval->test_started) {
193 		up_write(&crypto_alg_sem);
194 		return;
195 	}
196 
197 	larval->test_started = true;
198 	up_write(&crypto_alg_sem);
199 
200 	crypto_wait_for_test(larval);
201 }
202 
203 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
204 {
205 	struct crypto_larval *larval = (void *)alg;
206 	long timeout;
207 
208 	if (!static_branch_likely(&crypto_boot_test_finished))
209 		crypto_start_test(larval);
210 
211 	timeout = wait_for_completion_killable_timeout(
212 		&larval->completion, 60 * HZ);
213 
214 	alg = larval->adult;
215 	if (timeout < 0)
216 		alg = ERR_PTR(-EINTR);
217 	else if (!timeout)
218 		alg = ERR_PTR(-ETIMEDOUT);
219 	else if (!alg)
220 		alg = ERR_PTR(-ENOENT);
221 	else if (IS_ERR(alg))
222 		;
223 	else if (crypto_is_test_larval(larval) &&
224 		 !(alg->cra_flags & CRYPTO_ALG_TESTED))
225 		alg = ERR_PTR(-EAGAIN);
226 	else if (alg->cra_flags & CRYPTO_ALG_FIPS_INTERNAL)
227 		alg = ERR_PTR(-EAGAIN);
228 	else if (!crypto_mod_get(alg))
229 		alg = ERR_PTR(-EAGAIN);
230 	crypto_mod_put(&larval->alg);
231 
232 	return alg;
233 }
234 
235 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
236 					    u32 mask)
237 {
238 	const u32 fips = CRYPTO_ALG_FIPS_INTERNAL;
239 	struct crypto_alg *alg;
240 	u32 test = 0;
241 
242 	if (!((type | mask) & CRYPTO_ALG_TESTED))
243 		test |= CRYPTO_ALG_TESTED;
244 
245 	down_read(&crypto_alg_sem);
246 	alg = __crypto_alg_lookup(name, (type | test) & ~fips,
247 				  (mask | test) & ~fips);
248 	if (alg) {
249 		if (((type | mask) ^ fips) & fips)
250 			mask |= fips;
251 		mask &= fips;
252 
253 		if (!crypto_is_larval(alg) &&
254 		    ((type ^ alg->cra_flags) & mask)) {
255 			/* Algorithm is disallowed in FIPS mode. */
256 			crypto_mod_put(alg);
257 			alg = ERR_PTR(-ENOENT);
258 		}
259 	} else if (test) {
260 		alg = __crypto_alg_lookup(name, type, mask);
261 		if (alg && !crypto_is_larval(alg)) {
262 			/* Test failed */
263 			crypto_mod_put(alg);
264 			alg = ERR_PTR(-ELIBBAD);
265 		}
266 	}
267 	up_read(&crypto_alg_sem);
268 
269 	return alg;
270 }
271 
272 static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
273 					       u32 mask)
274 {
275 	struct crypto_alg *alg;
276 
277 	if (!name)
278 		return ERR_PTR(-ENOENT);
279 
280 	type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
281 	mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
282 
283 	alg = crypto_alg_lookup(name, type, mask);
284 	if (!alg && !(mask & CRYPTO_NOLOAD)) {
285 		request_module("crypto-%s", name);
286 
287 		if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
288 		      CRYPTO_ALG_NEED_FALLBACK))
289 			request_module("crypto-%s-all", name);
290 
291 		alg = crypto_alg_lookup(name, type, mask);
292 	}
293 
294 	if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
295 		alg = crypto_larval_wait(alg);
296 	else if (!alg)
297 		alg = crypto_larval_add(name, type, mask);
298 
299 	return alg;
300 }
301 
302 int crypto_probing_notify(unsigned long val, void *v)
303 {
304 	int ok;
305 
306 	ok = blocking_notifier_call_chain(&crypto_chain, val, v);
307 	if (ok == NOTIFY_DONE) {
308 		request_module("cryptomgr");
309 		ok = blocking_notifier_call_chain(&crypto_chain, val, v);
310 	}
311 
312 	return ok;
313 }
314 EXPORT_SYMBOL_GPL(crypto_probing_notify);
315 
316 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
317 {
318 	struct crypto_alg *alg;
319 	struct crypto_alg *larval;
320 	int ok;
321 
322 	/*
323 	 * If the internal flag is set for a cipher, require a caller to
324 	 * to invoke the cipher with the internal flag to use that cipher.
325 	 * Also, if a caller wants to allocate a cipher that may or may
326 	 * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
327 	 * !(mask & CRYPTO_ALG_INTERNAL).
328 	 */
329 	if (!((type | mask) & CRYPTO_ALG_INTERNAL))
330 		mask |= CRYPTO_ALG_INTERNAL;
331 
332 	larval = crypto_larval_lookup(name, type, mask);
333 	if (IS_ERR(larval) || !crypto_is_larval(larval))
334 		return larval;
335 
336 	ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
337 
338 	if (ok == NOTIFY_STOP)
339 		alg = crypto_larval_wait(larval);
340 	else {
341 		crypto_mod_put(larval);
342 		alg = ERR_PTR(-ENOENT);
343 	}
344 	crypto_larval_kill(larval);
345 	return alg;
346 }
347 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
348 
349 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
350 {
351 	const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
352 
353 	if (type_obj)
354 		return type_obj->init(tfm, type, mask);
355 	return 0;
356 }
357 
358 static void crypto_exit_ops(struct crypto_tfm *tfm)
359 {
360 	const struct crypto_type *type = tfm->__crt_alg->cra_type;
361 
362 	if (type && tfm->exit)
363 		tfm->exit(tfm);
364 }
365 
366 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
367 {
368 	const struct crypto_type *type_obj = alg->cra_type;
369 	unsigned int len;
370 
371 	len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
372 	if (type_obj)
373 		return len + type_obj->ctxsize(alg, type, mask);
374 
375 	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
376 	default:
377 		BUG();
378 
379 	case CRYPTO_ALG_TYPE_CIPHER:
380 		len += crypto_cipher_ctxsize(alg);
381 		break;
382 
383 	case CRYPTO_ALG_TYPE_COMPRESS:
384 		len += crypto_compress_ctxsize(alg);
385 		break;
386 	}
387 
388 	return len;
389 }
390 
391 void crypto_shoot_alg(struct crypto_alg *alg)
392 {
393 	down_write(&crypto_alg_sem);
394 	alg->cra_flags |= CRYPTO_ALG_DYING;
395 	up_write(&crypto_alg_sem);
396 }
397 EXPORT_SYMBOL_GPL(crypto_shoot_alg);
398 
399 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
400 				      u32 mask)
401 {
402 	struct crypto_tfm *tfm = NULL;
403 	unsigned int tfm_size;
404 	int err = -ENOMEM;
405 
406 	tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
407 	tfm = kzalloc(tfm_size, GFP_KERNEL);
408 	if (tfm == NULL)
409 		goto out_err;
410 
411 	tfm->__crt_alg = alg;
412 
413 	err = crypto_init_ops(tfm, type, mask);
414 	if (err)
415 		goto out_free_tfm;
416 
417 	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
418 		goto cra_init_failed;
419 
420 	goto out;
421 
422 cra_init_failed:
423 	crypto_exit_ops(tfm);
424 out_free_tfm:
425 	if (err == -EAGAIN)
426 		crypto_shoot_alg(alg);
427 	kfree(tfm);
428 out_err:
429 	tfm = ERR_PTR(err);
430 out:
431 	return tfm;
432 }
433 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
434 
435 /*
436  *	crypto_alloc_base - Locate algorithm and allocate transform
437  *	@alg_name: Name of algorithm
438  *	@type: Type of algorithm
439  *	@mask: Mask for type comparison
440  *
441  *	This function should not be used by new algorithm types.
442  *	Please use crypto_alloc_tfm instead.
443  *
444  *	crypto_alloc_base() will first attempt to locate an already loaded
445  *	algorithm.  If that fails and the kernel supports dynamically loadable
446  *	modules, it will then attempt to load a module of the same name or
447  *	alias.  If that fails it will send a query to any loaded crypto manager
448  *	to construct an algorithm on the fly.  A refcount is grabbed on the
449  *	algorithm which is then associated with the new transform.
450  *
451  *	The returned transform is of a non-determinate type.  Most people
452  *	should use one of the more specific allocation functions such as
453  *	crypto_alloc_skcipher().
454  *
455  *	In case of error the return value is an error pointer.
456  */
457 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
458 {
459 	struct crypto_tfm *tfm;
460 	int err;
461 
462 	for (;;) {
463 		struct crypto_alg *alg;
464 
465 		alg = crypto_alg_mod_lookup(alg_name, type, mask);
466 		if (IS_ERR(alg)) {
467 			err = PTR_ERR(alg);
468 			goto err;
469 		}
470 
471 		tfm = __crypto_alloc_tfm(alg, type, mask);
472 		if (!IS_ERR(tfm))
473 			return tfm;
474 
475 		crypto_mod_put(alg);
476 		err = PTR_ERR(tfm);
477 
478 err:
479 		if (err != -EAGAIN)
480 			break;
481 		if (fatal_signal_pending(current)) {
482 			err = -EINTR;
483 			break;
484 		}
485 	}
486 
487 	return ERR_PTR(err);
488 }
489 EXPORT_SYMBOL_GPL(crypto_alloc_base);
490 
491 void *crypto_create_tfm_node(struct crypto_alg *alg,
492 			const struct crypto_type *frontend,
493 			int node)
494 {
495 	char *mem;
496 	struct crypto_tfm *tfm = NULL;
497 	unsigned int tfmsize;
498 	unsigned int total;
499 	int err = -ENOMEM;
500 
501 	tfmsize = frontend->tfmsize;
502 	total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
503 
504 	mem = kzalloc_node(total, GFP_KERNEL, node);
505 	if (mem == NULL)
506 		goto out_err;
507 
508 	tfm = (struct crypto_tfm *)(mem + tfmsize);
509 	tfm->__crt_alg = alg;
510 	tfm->node = node;
511 
512 	err = frontend->init_tfm(tfm);
513 	if (err)
514 		goto out_free_tfm;
515 
516 	if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
517 		goto cra_init_failed;
518 
519 	goto out;
520 
521 cra_init_failed:
522 	crypto_exit_ops(tfm);
523 out_free_tfm:
524 	if (err == -EAGAIN)
525 		crypto_shoot_alg(alg);
526 	kfree(mem);
527 out_err:
528 	mem = ERR_PTR(err);
529 out:
530 	return mem;
531 }
532 EXPORT_SYMBOL_GPL(crypto_create_tfm_node);
533 
534 struct crypto_alg *crypto_find_alg(const char *alg_name,
535 				   const struct crypto_type *frontend,
536 				   u32 type, u32 mask)
537 {
538 	if (frontend) {
539 		type &= frontend->maskclear;
540 		mask &= frontend->maskclear;
541 		type |= frontend->type;
542 		mask |= frontend->maskset;
543 	}
544 
545 	return crypto_alg_mod_lookup(alg_name, type, mask);
546 }
547 EXPORT_SYMBOL_GPL(crypto_find_alg);
548 
549 /*
550  *	crypto_alloc_tfm_node - Locate algorithm and allocate transform
551  *	@alg_name: Name of algorithm
552  *	@frontend: Frontend algorithm type
553  *	@type: Type of algorithm
554  *	@mask: Mask for type comparison
555  *	@node: NUMA node in which users desire to put requests, if node is
556  *		NUMA_NO_NODE, it means users have no special requirement.
557  *
558  *	crypto_alloc_tfm() will first attempt to locate an already loaded
559  *	algorithm.  If that fails and the kernel supports dynamically loadable
560  *	modules, it will then attempt to load a module of the same name or
561  *	alias.  If that fails it will send a query to any loaded crypto manager
562  *	to construct an algorithm on the fly.  A refcount is grabbed on the
563  *	algorithm which is then associated with the new transform.
564  *
565  *	The returned transform is of a non-determinate type.  Most people
566  *	should use one of the more specific allocation functions such as
567  *	crypto_alloc_skcipher().
568  *
569  *	In case of error the return value is an error pointer.
570  */
571 
572 void *crypto_alloc_tfm_node(const char *alg_name,
573 		       const struct crypto_type *frontend, u32 type, u32 mask,
574 		       int node)
575 {
576 	void *tfm;
577 	int err;
578 
579 	for (;;) {
580 		struct crypto_alg *alg;
581 
582 		alg = crypto_find_alg(alg_name, frontend, type, mask);
583 		if (IS_ERR(alg)) {
584 			err = PTR_ERR(alg);
585 			goto err;
586 		}
587 
588 		tfm = crypto_create_tfm_node(alg, frontend, node);
589 		if (!IS_ERR(tfm))
590 			return tfm;
591 
592 		crypto_mod_put(alg);
593 		err = PTR_ERR(tfm);
594 
595 err:
596 		if (err != -EAGAIN)
597 			break;
598 		if (fatal_signal_pending(current)) {
599 			err = -EINTR;
600 			break;
601 		}
602 	}
603 
604 	return ERR_PTR(err);
605 }
606 EXPORT_SYMBOL_GPL(crypto_alloc_tfm_node);
607 
608 /*
609  *	crypto_destroy_tfm - Free crypto transform
610  *	@mem: Start of tfm slab
611  *	@tfm: Transform to free
612  *
613  *	This function frees up the transform and any associated resources,
614  *	then drops the refcount on the associated algorithm.
615  */
616 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
617 {
618 	struct crypto_alg *alg;
619 
620 	if (IS_ERR_OR_NULL(mem))
621 		return;
622 
623 	alg = tfm->__crt_alg;
624 
625 	if (!tfm->exit && alg->cra_exit)
626 		alg->cra_exit(tfm);
627 	crypto_exit_ops(tfm);
628 	crypto_mod_put(alg);
629 	kfree_sensitive(mem);
630 }
631 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
632 
633 int crypto_has_alg(const char *name, u32 type, u32 mask)
634 {
635 	int ret = 0;
636 	struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
637 
638 	if (!IS_ERR(alg)) {
639 		crypto_mod_put(alg);
640 		ret = 1;
641 	}
642 
643 	return ret;
644 }
645 EXPORT_SYMBOL_GPL(crypto_has_alg);
646 
647 void crypto_req_done(struct crypto_async_request *req, int err)
648 {
649 	struct crypto_wait *wait = req->data;
650 
651 	if (err == -EINPROGRESS)
652 		return;
653 
654 	wait->err = err;
655 	complete(&wait->completion);
656 }
657 EXPORT_SYMBOL_GPL(crypto_req_done);
658 
659 MODULE_DESCRIPTION("Cryptographic core API");
660 MODULE_LICENSE("GPL");
661