xref: /kernel/linux/linux-5.10/crypto/shash.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Synchronous Cryptographic Hash operations.
4 *
5 * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8#include <crypto/scatterwalk.h>
9#include <crypto/internal/hash.h>
10#include <linux/err.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/slab.h>
14#include <linux/seq_file.h>
15#include <linux/cryptouser.h>
16#include <net/netlink.h>
17#include <linux/compiler.h>
18
19#include "internal.h"
20
21static const struct crypto_type crypto_shash_type;
22
23static int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,
24			   unsigned int keylen)
25{
26	return -ENOSYS;
27}
28
29/*
30 * Check whether an shash algorithm has a setkey function.
31 *
32 * For CFI compatibility, this must not be an inline function.  This is because
33 * when CFI is enabled, modules won't get the same address for shash_no_setkey
34 * (if it were exported, which inlining would require) as the core kernel will.
35 */
36bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
37{
38	return alg->setkey != shash_no_setkey;
39}
40EXPORT_SYMBOL_GPL(crypto_shash_alg_has_setkey);
41
42static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
43				  unsigned int keylen)
44{
45	struct shash_alg *shash = crypto_shash_alg(tfm);
46	unsigned long alignmask = crypto_shash_alignmask(tfm);
47	unsigned long absize;
48	u8 *buffer, *alignbuffer;
49	int err;
50
51	absize = keylen + (alignmask & ~(crypto_tfm_ctx_alignment() - 1));
52	buffer = kmalloc(absize, GFP_ATOMIC);
53	if (!buffer)
54		return -ENOMEM;
55
56	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
57	memcpy(alignbuffer, key, keylen);
58	err = shash->setkey(tfm, alignbuffer, keylen);
59	kfree_sensitive(buffer);
60	return err;
61}
62
63static void shash_set_needkey(struct crypto_shash *tfm, struct shash_alg *alg)
64{
65	if (crypto_shash_alg_needs_key(alg))
66		crypto_shash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
67}
68
69int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
70			unsigned int keylen)
71{
72	struct shash_alg *shash = crypto_shash_alg(tfm);
73	unsigned long alignmask = crypto_shash_alignmask(tfm);
74	int err;
75
76	if ((unsigned long)key & alignmask)
77		err = shash_setkey_unaligned(tfm, key, keylen);
78	else
79		err = shash->setkey(tfm, key, keylen);
80
81	if (unlikely(err)) {
82		shash_set_needkey(tfm, shash);
83		return err;
84	}
85
86	crypto_shash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
87	return 0;
88}
89EXPORT_SYMBOL_GPL(crypto_shash_setkey);
90
91static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
92				  unsigned int len)
93{
94	struct crypto_shash *tfm = desc->tfm;
95	struct shash_alg *shash = crypto_shash_alg(tfm);
96	unsigned long alignmask = crypto_shash_alignmask(tfm);
97	unsigned int unaligned_len = alignmask + 1 -
98				     ((unsigned long)data & alignmask);
99	/*
100	 * We cannot count on __aligned() working for large values:
101	 * https://patchwork.kernel.org/patch/9507697/
102	 */
103	u8 ubuf[MAX_ALGAPI_ALIGNMASK * 2];
104	u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
105	int err;
106
107	if (WARN_ON(buf + unaligned_len > ubuf + sizeof(ubuf)))
108		return -EINVAL;
109
110	if (unaligned_len > len)
111		unaligned_len = len;
112
113	memcpy(buf, data, unaligned_len);
114	err = shash->update(desc, buf, unaligned_len);
115	memset(buf, 0, unaligned_len);
116
117	return err ?:
118	       shash->update(desc, data + unaligned_len, len - unaligned_len);
119}
120
121int crypto_shash_update(struct shash_desc *desc, const u8 *data,
122			unsigned int len)
123{
124	struct crypto_shash *tfm = desc->tfm;
125	struct shash_alg *shash = crypto_shash_alg(tfm);
126	unsigned long alignmask = crypto_shash_alignmask(tfm);
127
128	if ((unsigned long)data & alignmask)
129		return shash_update_unaligned(desc, data, len);
130
131	return shash->update(desc, data, len);
132}
133EXPORT_SYMBOL_GPL(crypto_shash_update);
134
135static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
136{
137	struct crypto_shash *tfm = desc->tfm;
138	unsigned long alignmask = crypto_shash_alignmask(tfm);
139	struct shash_alg *shash = crypto_shash_alg(tfm);
140	unsigned int ds = crypto_shash_digestsize(tfm);
141	/*
142	 * We cannot count on __aligned() working for large values:
143	 * https://patchwork.kernel.org/patch/9507697/
144	 */
145	u8 ubuf[MAX_ALGAPI_ALIGNMASK + HASH_MAX_DIGESTSIZE];
146	u8 *buf = PTR_ALIGN(&ubuf[0], alignmask + 1);
147	int err;
148
149	if (WARN_ON(buf + ds > ubuf + sizeof(ubuf)))
150		return -EINVAL;
151
152	err = shash->final(desc, buf);
153	if (err)
154		goto out;
155
156	memcpy(out, buf, ds);
157
158out:
159	memset(buf, 0, ds);
160	return err;
161}
162
163int crypto_shash_final(struct shash_desc *desc, u8 *out)
164{
165	struct crypto_shash *tfm = desc->tfm;
166	struct shash_alg *shash = crypto_shash_alg(tfm);
167	unsigned long alignmask = crypto_shash_alignmask(tfm);
168
169	if ((unsigned long)out & alignmask)
170		return shash_final_unaligned(desc, out);
171
172	return shash->final(desc, out);
173}
174EXPORT_SYMBOL_GPL(crypto_shash_final);
175
176static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
177				 unsigned int len, u8 *out)
178{
179	return crypto_shash_update(desc, data, len) ?:
180	       crypto_shash_final(desc, out);
181}
182
183int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
184		       unsigned int len, u8 *out)
185{
186	struct crypto_shash *tfm = desc->tfm;
187	struct shash_alg *shash = crypto_shash_alg(tfm);
188	unsigned long alignmask = crypto_shash_alignmask(tfm);
189
190	if (((unsigned long)data | (unsigned long)out) & alignmask)
191		return shash_finup_unaligned(desc, data, len, out);
192
193	return shash->finup(desc, data, len, out);
194}
195EXPORT_SYMBOL_GPL(crypto_shash_finup);
196
197static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
198				  unsigned int len, u8 *out)
199{
200	return crypto_shash_init(desc) ?:
201	       crypto_shash_finup(desc, data, len, out);
202}
203
204int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
205			unsigned int len, u8 *out)
206{
207	struct crypto_shash *tfm = desc->tfm;
208	struct shash_alg *shash = crypto_shash_alg(tfm);
209	unsigned long alignmask = crypto_shash_alignmask(tfm);
210
211	if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
212		return -ENOKEY;
213
214	if (((unsigned long)data | (unsigned long)out) & alignmask)
215		return shash_digest_unaligned(desc, data, len, out);
216
217	return shash->digest(desc, data, len, out);
218}
219EXPORT_SYMBOL_GPL(crypto_shash_digest);
220
221int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
222			    unsigned int len, u8 *out)
223{
224	SHASH_DESC_ON_STACK(desc, tfm);
225	int err;
226
227	desc->tfm = tfm;
228
229	err = crypto_shash_digest(desc, data, len, out);
230
231	shash_desc_zero(desc);
232
233	return err;
234}
235EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);
236
237static int shash_default_export(struct shash_desc *desc, void *out)
238{
239	memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
240	return 0;
241}
242
243static int shash_default_import(struct shash_desc *desc, const void *in)
244{
245	memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
246	return 0;
247}
248
249static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
250			      unsigned int keylen)
251{
252	struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
253
254	return crypto_shash_setkey(*ctx, key, keylen);
255}
256
257static int shash_async_init(struct ahash_request *req)
258{
259	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
260	struct shash_desc *desc = ahash_request_ctx(req);
261
262	desc->tfm = *ctx;
263
264	return crypto_shash_init(desc);
265}
266
267int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
268{
269	struct crypto_hash_walk walk;
270	int nbytes;
271
272	for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
273	     nbytes = crypto_hash_walk_done(&walk, nbytes))
274		nbytes = crypto_shash_update(desc, walk.data, nbytes);
275
276	return nbytes;
277}
278EXPORT_SYMBOL_GPL(shash_ahash_update);
279
280static int shash_async_update(struct ahash_request *req)
281{
282	return shash_ahash_update(req, ahash_request_ctx(req));
283}
284
285static int shash_async_final(struct ahash_request *req)
286{
287	return crypto_shash_final(ahash_request_ctx(req), req->result);
288}
289
290int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
291{
292	struct crypto_hash_walk walk;
293	int nbytes;
294
295	nbytes = crypto_hash_walk_first(req, &walk);
296	if (!nbytes)
297		return crypto_shash_final(desc, req->result);
298
299	do {
300		nbytes = crypto_hash_walk_last(&walk) ?
301			 crypto_shash_finup(desc, walk.data, nbytes,
302					    req->result) :
303			 crypto_shash_update(desc, walk.data, nbytes);
304		nbytes = crypto_hash_walk_done(&walk, nbytes);
305	} while (nbytes > 0);
306
307	return nbytes;
308}
309EXPORT_SYMBOL_GPL(shash_ahash_finup);
310
311static int shash_async_finup(struct ahash_request *req)
312{
313	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
314	struct shash_desc *desc = ahash_request_ctx(req);
315
316	desc->tfm = *ctx;
317
318	return shash_ahash_finup(req, desc);
319}
320
321int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
322{
323	unsigned int nbytes = req->nbytes;
324	struct scatterlist *sg;
325	unsigned int offset;
326	int err;
327
328	if (nbytes &&
329	    (sg = req->src, offset = sg->offset,
330	     nbytes <= min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset))) {
331		void *data;
332
333		data = kmap_atomic(sg_page(sg));
334		err = crypto_shash_digest(desc, data + offset, nbytes,
335					  req->result);
336		kunmap_atomic(data);
337	} else
338		err = crypto_shash_init(desc) ?:
339		      shash_ahash_finup(req, desc);
340
341	return err;
342}
343EXPORT_SYMBOL_GPL(shash_ahash_digest);
344
345static int shash_async_digest(struct ahash_request *req)
346{
347	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
348	struct shash_desc *desc = ahash_request_ctx(req);
349
350	desc->tfm = *ctx;
351
352	return shash_ahash_digest(req, desc);
353}
354
355static int shash_async_export(struct ahash_request *req, void *out)
356{
357	return crypto_shash_export(ahash_request_ctx(req), out);
358}
359
360static int shash_async_import(struct ahash_request *req, const void *in)
361{
362	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
363	struct shash_desc *desc = ahash_request_ctx(req);
364
365	desc->tfm = *ctx;
366
367	return crypto_shash_import(desc, in);
368}
369
370static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
371{
372	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
373
374	crypto_free_shash(*ctx);
375}
376
377int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
378{
379	struct crypto_alg *calg = tfm->__crt_alg;
380	struct shash_alg *alg = __crypto_shash_alg(calg);
381	struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
382	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
383	struct crypto_shash *shash;
384
385	if (!crypto_mod_get(calg))
386		return -EAGAIN;
387
388	shash = crypto_create_tfm(calg, &crypto_shash_type);
389	if (IS_ERR(shash)) {
390		crypto_mod_put(calg);
391		return PTR_ERR(shash);
392	}
393
394	*ctx = shash;
395	tfm->exit = crypto_exit_shash_ops_async;
396
397	crt->init = shash_async_init;
398	crt->update = shash_async_update;
399	crt->final = shash_async_final;
400	crt->finup = shash_async_finup;
401	crt->digest = shash_async_digest;
402	if (crypto_shash_alg_has_setkey(alg))
403		crt->setkey = shash_async_setkey;
404
405	crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
406				    CRYPTO_TFM_NEED_KEY);
407
408	crt->export = shash_async_export;
409	crt->import = shash_async_import;
410
411	crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
412
413	return 0;
414}
415
416static void crypto_shash_exit_tfm(struct crypto_tfm *tfm)
417{
418	struct crypto_shash *hash = __crypto_shash_cast(tfm);
419	struct shash_alg *alg = crypto_shash_alg(hash);
420
421	alg->exit_tfm(hash);
422}
423
424static int crypto_shash_init_tfm(struct crypto_tfm *tfm)
425{
426	struct crypto_shash *hash = __crypto_shash_cast(tfm);
427	struct shash_alg *alg = crypto_shash_alg(hash);
428	int err;
429
430	hash->descsize = alg->descsize;
431
432	shash_set_needkey(hash, alg);
433
434	if (alg->exit_tfm)
435		tfm->exit = crypto_shash_exit_tfm;
436
437	if (!alg->init_tfm)
438		return 0;
439
440	err = alg->init_tfm(hash);
441	if (err)
442		return err;
443
444	/* ->init_tfm() may have increased the descsize. */
445	if (WARN_ON_ONCE(hash->descsize > HASH_MAX_DESCSIZE)) {
446		if (alg->exit_tfm)
447			alg->exit_tfm(hash);
448		return -EINVAL;
449	}
450
451	return 0;
452}
453
454static void crypto_shash_free_instance(struct crypto_instance *inst)
455{
456	struct shash_instance *shash = shash_instance(inst);
457
458	shash->free(shash);
459}
460
461#ifdef CONFIG_NET
462static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
463{
464	struct crypto_report_hash rhash;
465	struct shash_alg *salg = __crypto_shash_alg(alg);
466
467	memset(&rhash, 0, sizeof(rhash));
468
469	strscpy(rhash.type, "shash", sizeof(rhash.type));
470
471	rhash.blocksize = alg->cra_blocksize;
472	rhash.digestsize = salg->digestsize;
473
474	return nla_put(skb, CRYPTOCFGA_REPORT_HASH, sizeof(rhash), &rhash);
475}
476#else
477static int crypto_shash_report(struct sk_buff *skb, struct crypto_alg *alg)
478{
479	return -ENOSYS;
480}
481#endif
482
483static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
484	__maybe_unused;
485static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
486{
487	struct shash_alg *salg = __crypto_shash_alg(alg);
488
489	seq_printf(m, "type         : shash\n");
490	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
491	seq_printf(m, "digestsize   : %u\n", salg->digestsize);
492}
493
494static const struct crypto_type crypto_shash_type = {
495	.extsize = crypto_alg_extsize,
496	.init_tfm = crypto_shash_init_tfm,
497	.free = crypto_shash_free_instance,
498#ifdef CONFIG_PROC_FS
499	.show = crypto_shash_show,
500#endif
501	.report = crypto_shash_report,
502	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
503	.maskset = CRYPTO_ALG_TYPE_MASK,
504	.type = CRYPTO_ALG_TYPE_SHASH,
505	.tfmsize = offsetof(struct crypto_shash, base),
506};
507
508int crypto_grab_shash(struct crypto_shash_spawn *spawn,
509		      struct crypto_instance *inst,
510		      const char *name, u32 type, u32 mask)
511{
512	spawn->base.frontend = &crypto_shash_type;
513	return crypto_grab_spawn(&spawn->base, inst, name, type, mask);
514}
515EXPORT_SYMBOL_GPL(crypto_grab_shash);
516
517struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
518					u32 mask)
519{
520	return crypto_alloc_tfm(alg_name, &crypto_shash_type, type, mask);
521}
522EXPORT_SYMBOL_GPL(crypto_alloc_shash);
523
524static int shash_prepare_alg(struct shash_alg *alg)
525{
526	struct crypto_alg *base = &alg->base;
527
528	if (alg->digestsize > HASH_MAX_DIGESTSIZE ||
529	    alg->descsize > HASH_MAX_DESCSIZE ||
530	    alg->statesize > HASH_MAX_STATESIZE)
531		return -EINVAL;
532
533	if ((alg->export && !alg->import) || (alg->import && !alg->export))
534		return -EINVAL;
535
536	base->cra_type = &crypto_shash_type;
537	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
538	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
539
540	if (!alg->finup)
541		alg->finup = shash_finup_unaligned;
542	if (!alg->digest)
543		alg->digest = shash_digest_unaligned;
544	if (!alg->export) {
545		alg->export = shash_default_export;
546		alg->import = shash_default_import;
547		alg->statesize = alg->descsize;
548	}
549	if (!alg->setkey)
550		alg->setkey = shash_no_setkey;
551
552	return 0;
553}
554
555int crypto_register_shash(struct shash_alg *alg)
556{
557	struct crypto_alg *base = &alg->base;
558	int err;
559
560	err = shash_prepare_alg(alg);
561	if (err)
562		return err;
563
564	return crypto_register_alg(base);
565}
566EXPORT_SYMBOL_GPL(crypto_register_shash);
567
568void crypto_unregister_shash(struct shash_alg *alg)
569{
570	crypto_unregister_alg(&alg->base);
571}
572EXPORT_SYMBOL_GPL(crypto_unregister_shash);
573
574int crypto_register_shashes(struct shash_alg *algs, int count)
575{
576	int i, ret;
577
578	for (i = 0; i < count; i++) {
579		ret = crypto_register_shash(&algs[i]);
580		if (ret)
581			goto err;
582	}
583
584	return 0;
585
586err:
587	for (--i; i >= 0; --i)
588		crypto_unregister_shash(&algs[i]);
589
590	return ret;
591}
592EXPORT_SYMBOL_GPL(crypto_register_shashes);
593
594void crypto_unregister_shashes(struct shash_alg *algs, int count)
595{
596	int i;
597
598	for (i = count - 1; i >= 0; --i)
599		crypto_unregister_shash(&algs[i]);
600}
601EXPORT_SYMBOL_GPL(crypto_unregister_shashes);
602
603int shash_register_instance(struct crypto_template *tmpl,
604			    struct shash_instance *inst)
605{
606	int err;
607
608	if (WARN_ON(!inst->free))
609		return -EINVAL;
610
611	err = shash_prepare_alg(&inst->alg);
612	if (err)
613		return err;
614
615	return crypto_register_instance(tmpl, shash_crypto_instance(inst));
616}
617EXPORT_SYMBOL_GPL(shash_register_instance);
618
619void shash_free_singlespawn_instance(struct shash_instance *inst)
620{
621	crypto_drop_spawn(shash_instance_ctx(inst));
622	kfree(inst);
623}
624EXPORT_SYMBOL_GPL(shash_free_singlespawn_instance);
625
626MODULE_LICENSE("GPL");
627MODULE_DESCRIPTION("Synchronous cryptographic hash type");
628