[linux-block.git] / crypto / hmac.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cryptographic API.
 *
 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * The HMAC implementation is derived from USAGI.
 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
 */

#include <crypto/hmac.h>
#include <crypto/internal/hash.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/fips.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/string.h>

struct hmac_ctx {
	struct crypto_shash *hash;
};

static inline void *align_ptr(void *p, unsigned int align)
{
	return (void *)ALIGN((unsigned long)p, align);
}

static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
{
	return align_ptr(crypto_shash_ctx_aligned(tfm) +
			 crypto_shash_statesize(tfm) * 2,
			 crypto_tfm_ctx_alignment());
}

static int hmac_setkey(struct crypto_shash *parent,
		       const u8 *inkey, unsigned int keylen)
{
	int bs = crypto_shash_blocksize(parent);
	int ds = crypto_shash_digestsize(parent);
	int ss = crypto_shash_statesize(parent);
	char *ipad = crypto_shash_ctx_aligned(parent);
	char *opad = ipad + ss;
	struct hmac_ctx *ctx = align_ptr(opad + ss,
					 crypto_tfm_ctx_alignment());
	struct crypto_shash *hash = ctx->hash;
	SHASH_DESC_ON_STACK(shash, hash);
	unsigned int i;

	if (fips_enabled && (keylen < 112 / 8))
		return -EINVAL;

	shash->tfm = hash;

	if (keylen > bs) {
		int err;

		err = crypto_shash_digest(shash, inkey, keylen, ipad);
		if (err)
			return err;

		keylen = ds;
	} else
		memcpy(ipad, inkey, keylen);

	memset(ipad + keylen, 0, bs - keylen);
	memcpy(opad, ipad, bs);

	for (i = 0; i < bs; i++) {
		ipad[i] ^= HMAC_IPAD_VALUE;
		opad[i] ^= HMAC_OPAD_VALUE;
	}

	return crypto_shash_init(shash) ?:
	       crypto_shash_update(shash, ipad, bs) ?:
	       crypto_shash_export(shash, ipad) ?:
	       crypto_shash_init(shash) ?:
	       crypto_shash_update(shash, opad, bs) ?:
	       crypto_shash_export(shash, opad);
}

static int hmac_export(struct shash_desc *pdesc, void *out)
{
	struct shash_desc *desc = shash_desc_ctx(pdesc);

	return crypto_shash_export(desc, out);
}

static int hmac_import(struct shash_desc *pdesc, const void *in)
{
	struct shash_desc *desc = shash_desc_ctx(pdesc);
	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);

	desc->tfm = ctx->hash;

	return crypto_shash_import(desc, in);
}

static int hmac_init(struct shash_desc *pdesc)
{
	return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
}

static int hmac_update(struct shash_desc *pdesc,
		       const u8 *data, unsigned int nbytes)
{
	struct shash_desc *desc = shash_desc_ctx(pdesc);

	return crypto_shash_update(desc, data, nbytes);
}

static int hmac_final(struct shash_desc *pdesc, u8 *out)
{
	struct crypto_shash *parent = pdesc->tfm;
	int ds = crypto_shash_digestsize(parent);
	int ss = crypto_shash_statesize(parent);
	char *opad = crypto_shash_ctx_aligned(parent) + ss;
	struct shash_desc *desc = shash_desc_ctx(pdesc);

	return crypto_shash_final(desc, out) ?:
	       crypto_shash_import(desc, opad) ?:
	       crypto_shash_finup(desc, out, ds, out);
}

static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
		      unsigned int nbytes, u8 *out)
{

	struct crypto_shash *parent = pdesc->tfm;
	int ds = crypto_shash_digestsize(parent);
	int ss = crypto_shash_statesize(parent);
	char *opad = crypto_shash_ctx_aligned(parent) + ss;
	struct shash_desc *desc = shash_desc_ctx(pdesc);

	return crypto_shash_finup(desc, data, nbytes, out) ?:
	       crypto_shash_import(desc, opad) ?:
	       crypto_shash_finup(desc, out, ds, out);
}

static int hmac_init_tfm(struct crypto_shash *parent)
{
	struct crypto_shash *hash;
	struct shash_instance *inst = shash_alg_instance(parent);
	struct crypto_shash_spawn *spawn = shash_instance_ctx(inst);
	struct hmac_ctx *ctx = hmac_ctx(parent);

	hash = crypto_spawn_shash(spawn);
	if (IS_ERR(hash))
		return PTR_ERR(hash);

	parent->descsize = sizeof(struct shash_desc) +
			   crypto_shash_descsize(hash);

	ctx->hash = hash;
	return 0;
}

static int hmac_clone_tfm(struct crypto_shash *dst, struct crypto_shash *src)
{
	struct hmac_ctx *sctx = hmac_ctx(src);
	struct hmac_ctx *dctx = hmac_ctx(dst);
	struct crypto_shash *hash;

	hash = crypto_clone_shash(sctx->hash);
	if (IS_ERR(hash))
		return PTR_ERR(hash);

	dctx->hash = hash;
	return 0;
}

static void hmac_exit_tfm(struct crypto_shash *parent)
{
	struct hmac_ctx *ctx = hmac_ctx(parent);
	crypto_free_shash(ctx->hash);
}

static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
{
	struct shash_instance *inst;
	struct crypto_shash_spawn *spawn;
	struct crypto_alg *alg;
	struct shash_alg *salg;
	u32 mask;
	int err;
	int ds;
	int ss;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
	if (err)
		return err;

	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
	if (!inst)
		return -ENOMEM;
	spawn = shash_instance_ctx(inst);

	err = crypto_grab_shash(spawn, shash_crypto_instance(inst),
				crypto_attr_alg_name(tb[1]), 0, mask);
	if (err)
		goto err_free_inst;
	salg = crypto_spawn_shash_alg(spawn);
	alg = &salg->base;

	/* The underlying hash algorithm must not require a key */
	err = -EINVAL;
	if (crypto_shash_alg_needs_key(salg))
		goto err_free_inst;

	ds = salg->digestsize;
	ss = salg->statesize;
	if (ds > alg->cra_blocksize ||
	    ss < alg->cra_blocksize)
		goto err_free_inst;

	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
	if (err)
		goto err_free_inst;

	inst->alg.base.cra_priority = alg->cra_priority;
	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	inst->alg.base.cra_alignmask = alg->cra_alignmask;

	ss = ALIGN(ss, alg->cra_alignmask + 1);
	inst->alg.digestsize = ds;
	inst->alg.statesize = ss;

	inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
				     ALIGN(ss * 2, crypto_tfm_ctx_alignment());

	inst->alg.init = hmac_init;
	inst->alg.update = hmac_update;
	inst->alg.final = hmac_final;
	inst->alg.finup = hmac_finup;
	inst->alg.export = hmac_export;
	inst->alg.import = hmac_import;
	inst->alg.setkey = hmac_setkey;
	inst->alg.init_tfm = hmac_init_tfm;
	inst->alg.clone_tfm = hmac_clone_tfm;
	inst->alg.exit_tfm = hmac_exit_tfm;

	inst->free = shash_free_singlespawn_instance;

	err = shash_register_instance(tmpl, inst);
	if (err) {
err_free_inst:
		shash_free_singlespawn_instance(inst);
	}
	return err;
}

static struct crypto_template hmac_tmpl = {
	.name = "hmac",
	.create = hmac_create,
	.module = THIS_MODULE,
};

static int __init hmac_module_init(void)
{
	return crypto_register_template(&hmac_tmpl);
}

static void __exit hmac_module_exit(void)
{
	crypto_unregister_template(&hmac_tmpl);
}

subsys_initcall(hmac_module_init);
module_exit(hmac_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("HMAC hash algorithm");
MODULE_ALIAS_CRYPTO("hmac");
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/*
	3	* Cryptographic API.
	4	*
	5	* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
	6	*
	7	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
	8	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
	9	*
	10	* The HMAC implementation is derived from USAGI.
	11	* Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
	12	*/
	13
	14	#include <crypto/hmac.h>
	15	#include <crypto/internal/hash.h>
	16	#include <crypto/scatterwalk.h>
	17	#include <linux/err.h>
	18	#include <linux/fips.h>
	19	#include <linux/init.h>
	20	#include <linux/kernel.h>
	21	#include <linux/module.h>
	22	#include <linux/scatterlist.h>
	23	#include <linux/string.h>
	24
	25	struct hmac_ctx {
	26	struct crypto_shash *hash;
	27	};
	28
	29	static inline void align_ptr(void p, unsigned int align)
	30	{
	31	return (void *)ALIGN((unsigned long)p, align);
	32	}
	33
	34	static inline struct hmac_ctx hmac_ctx(struct crypto_shash tfm)
	35	{
	36	return align_ptr(crypto_shash_ctx_aligned(tfm) +
	37	crypto_shash_statesize(tfm) * 2,
	38	crypto_tfm_ctx_alignment());
	39	}
	40
	41	static int hmac_setkey(struct crypto_shash *parent,
	42	const u8 *inkey, unsigned int keylen)
	43	{
	44	int bs = crypto_shash_blocksize(parent);
	45	int ds = crypto_shash_digestsize(parent);
	46	int ss = crypto_shash_statesize(parent);
	47	char *ipad = crypto_shash_ctx_aligned(parent);
	48	char *opad = ipad + ss;
	49	struct hmac_ctx *ctx = align_ptr(opad + ss,
	50	crypto_tfm_ctx_alignment());
	51	struct crypto_shash *hash = ctx->hash;
	52	SHASH_DESC_ON_STACK(shash, hash);
	53	unsigned int i;
	54
	55	if (fips_enabled && (keylen < 112 / 8))
	56	return -EINVAL;
	57
	58	shash->tfm = hash;
	59
	60	if (keylen > bs) {
	61	int err;
	62
	63	err = crypto_shash_digest(shash, inkey, keylen, ipad);
	64	if (err)
	65	return err;
	66
	67	keylen = ds;
	68	} else
	69	memcpy(ipad, inkey, keylen);
	70
	71	memset(ipad + keylen, 0, bs - keylen);
	72	memcpy(opad, ipad, bs);
	73
	74	for (i = 0; i < bs; i++) {
	75	ipad[i] ^= HMAC_IPAD_VALUE;
	76	opad[i] ^= HMAC_OPAD_VALUE;
	77	}
	78
	79	return crypto_shash_init(shash) ?:
	80	crypto_shash_update(shash, ipad, bs) ?:
	81	crypto_shash_export(shash, ipad) ?:
	82	crypto_shash_init(shash) ?:
	83	crypto_shash_update(shash, opad, bs) ?:
	84	crypto_shash_export(shash, opad);
	85	}
	86
	87	static int hmac_export(struct shash_desc pdesc, void out)
	88	{
	89	struct shash_desc *desc = shash_desc_ctx(pdesc);
	90
	91	return crypto_shash_export(desc, out);
	92	}
	93
	94	static int hmac_import(struct shash_desc pdesc, const void in)
	95	{
	96	struct shash_desc *desc = shash_desc_ctx(pdesc);
	97	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
	98
	99	desc->tfm = ctx->hash;
	100
	101	return crypto_shash_import(desc, in);
	102	}
	103
	104	static int hmac_init(struct shash_desc *pdesc)
	105	{
	106	return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
	107	}
	108
	109	static int hmac_update(struct shash_desc *pdesc,
	110	const u8 *data, unsigned int nbytes)
	111	{
	112	struct shash_desc *desc = shash_desc_ctx(pdesc);
	113
	114	return crypto_shash_update(desc, data, nbytes);
	115	}
	116
	117	static int hmac_final(struct shash_desc pdesc, u8 out)
	118	{
	119	struct crypto_shash *parent = pdesc->tfm;
	120	int ds = crypto_shash_digestsize(parent);
	121	int ss = crypto_shash_statesize(parent);
	122	char *opad = crypto_shash_ctx_aligned(parent) + ss;
	123	struct shash_desc *desc = shash_desc_ctx(pdesc);
	124
	125	return crypto_shash_final(desc, out) ?:
	126	crypto_shash_import(desc, opad) ?:
	127	crypto_shash_finup(desc, out, ds, out);
	128	}
	129
	130	static int hmac_finup(struct shash_desc pdesc, const u8 data,
	131	unsigned int nbytes, u8 *out)
	132	{
	133
	134	struct crypto_shash *parent = pdesc->tfm;
	135	int ds = crypto_shash_digestsize(parent);
	136	int ss = crypto_shash_statesize(parent);
	137	char *opad = crypto_shash_ctx_aligned(parent) + ss;
	138	struct shash_desc *desc = shash_desc_ctx(pdesc);
	139
	140	return crypto_shash_finup(desc, data, nbytes, out) ?:
	141	crypto_shash_import(desc, opad) ?:
	142	crypto_shash_finup(desc, out, ds, out);
	143	}
	144
	145	static int hmac_init_tfm(struct crypto_shash *parent)
	146	{
	147	struct crypto_shash *hash;
	148	struct shash_instance *inst = shash_alg_instance(parent);
	149	struct crypto_shash_spawn *spawn = shash_instance_ctx(inst);
	150	struct hmac_ctx *ctx = hmac_ctx(parent);
	151
	152	hash = crypto_spawn_shash(spawn);
	153	if (IS_ERR(hash))
	154	return PTR_ERR(hash);
	155
	156	parent->descsize = sizeof(struct shash_desc) +
	157	crypto_shash_descsize(hash);
	158
	159	ctx->hash = hash;
	160	return 0;
	161	}
	162
	163	static int hmac_clone_tfm(struct crypto_shash dst, struct crypto_shash src)
	164	{
	165	struct hmac_ctx *sctx = hmac_ctx(src);
	166	struct hmac_ctx *dctx = hmac_ctx(dst);
	167	struct crypto_shash *hash;
	168
	169	hash = crypto_clone_shash(sctx->hash);
	170	if (IS_ERR(hash))
	171	return PTR_ERR(hash);
	172
	173	dctx->hash = hash;
	174	return 0;
	175	}
	176
	177	static void hmac_exit_tfm(struct crypto_shash *parent)
	178	{
	179	struct hmac_ctx *ctx = hmac_ctx(parent);
	180	crypto_free_shash(ctx->hash);
	181	}
	182
	183	static int hmac_create(struct crypto_template tmpl, struct rtattr *tb)
	184	{
	185	struct shash_instance *inst;
	186	struct crypto_shash_spawn *spawn;
	187	struct crypto_alg *alg;
	188	struct shash_alg *salg;
	189	u32 mask;
	190	int err;
	191	int ds;
	192	int ss;
	193
	194	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
	195	if (err)
	196	return err;
	197
	198	inst = kzalloc(sizeof(inst) + sizeof(spawn), GFP_KERNEL);
	199	if (!inst)
	200	return -ENOMEM;
	201	spawn = shash_instance_ctx(inst);
	202
	203	err = crypto_grab_shash(spawn, shash_crypto_instance(inst),
	204	crypto_attr_alg_name(tb[1]), 0, mask);
	205	if (err)
	206	goto err_free_inst;
	207	salg = crypto_spawn_shash_alg(spawn);
	208	alg = &salg->base;
	209
	210	/* The underlying hash algorithm must not require a key */
	211	err = -EINVAL;
	212	if (crypto_shash_alg_needs_key(salg))
	213	goto err_free_inst;
	214
	215	ds = salg->digestsize;
	216	ss = salg->statesize;
	217	if (ds > alg->cra_blocksize \|\|
	218	ss < alg->cra_blocksize)
	219	goto err_free_inst;
	220
	221	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
	222	if (err)
	223	goto err_free_inst;
	224
	225	inst->alg.base.cra_priority = alg->cra_priority;
	226	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	227	inst->alg.base.cra_alignmask = alg->cra_alignmask;
	228
	229	ss = ALIGN(ss, alg->cra_alignmask + 1);
	230	inst->alg.digestsize = ds;
	231	inst->alg.statesize = ss;
	232
	233	inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
	234	ALIGN(ss * 2, crypto_tfm_ctx_alignment());
	235
	236	inst->alg.init = hmac_init;
	237	inst->alg.update = hmac_update;
	238	inst->alg.final = hmac_final;
	239	inst->alg.finup = hmac_finup;
	240	inst->alg.export = hmac_export;
	241	inst->alg.import = hmac_import;
	242	inst->alg.setkey = hmac_setkey;
	243	inst->alg.init_tfm = hmac_init_tfm;
	244	inst->alg.clone_tfm = hmac_clone_tfm;
	245	inst->alg.exit_tfm = hmac_exit_tfm;
	246
	247	inst->free = shash_free_singlespawn_instance;
	248
	249	err = shash_register_instance(tmpl, inst);
	250	if (err) {
	251	err_free_inst:
	252	shash_free_singlespawn_instance(inst);
	253	}
	254	return err;
	255	}
	256
	257	static struct crypto_template hmac_tmpl = {
	258	.name = "hmac",
	259	.create = hmac_create,
	260	.module = THIS_MODULE,
	261	};
	262
	263	static int __init hmac_module_init(void)
	264	{
	265	return crypto_register_template(&hmac_tmpl);
	266	}
	267
	268	static void __exit hmac_module_exit(void)
	269	{
	270	crypto_unregister_template(&hmac_tmpl);
	271	}
	272
	273	subsys_initcall(hmac_module_init);
	274	module_exit(hmac_module_exit);
	275
	276	MODULE_LICENSE("GPL");
	277	MODULE_DESCRIPTION("HMAC hash algorithm");
	278	MODULE_ALIAS_CRYPTO("hmac");