[mirror_ubuntu-artful-kernel.git] / crypto / hmac.c

/*
 * 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
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/internal/hash.h>
#include <crypto/scatterwalk.h>
#include <linux/err.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;

	shash->tfm = hash;
	shash->flags = crypto_shash_get_flags(parent)
		& CRYPTO_TFM_REQ_MAY_SLEEP;

	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] ^= 0x36;
		opad[i] ^= 0x5c;
	}

	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);

	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	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;
	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	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);

	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	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);

	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	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);

	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	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_tfm *tfm)
{
	struct crypto_shash *parent = __crypto_shash_cast(tfm);
	struct crypto_shash *hash;
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_shash_spawn *spawn = crypto_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 void hmac_exit_tfm(struct crypto_tfm *tfm)
{
	struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
	crypto_free_shash(ctx->hash);
}

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

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

	salg = shash_attr_alg(tb[1], 0, 0);
	if (IS_ERR(salg))
		return PTR_ERR(salg);

	err = -EINVAL;
	ds = salg->digestsize;
	ss = salg->statesize;
	alg = &salg->base;
	if (ds > alg->cra_blocksize ||
	    ss < alg->cra_blocksize)
		goto out_put_alg;

	inst = shash_alloc_instance("hmac", alg);
	err = PTR_ERR(inst);
	if (IS_ERR(inst))
		goto out_put_alg;

	err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
				      shash_crypto_instance(inst));
	if (err)
		goto out_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.base.cra_init = hmac_init_tfm;
	inst->alg.base.cra_exit = hmac_exit_tfm;

	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;

	err = shash_register_instance(tmpl, inst);
	if (err) {
out_free_inst:
		shash_free_instance(shash_crypto_instance(inst));
	}

out_put_alg:
	crypto_mod_put(alg);
	return err;
}

static struct crypto_template hmac_tmpl = {
	.name = "hmac",
	.create = hmac_create,
	.free = shash_free_instance,
	.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);
}

module_init(hmac_module_init);
module_exit(hmac_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("HMAC hash algorithm");
MODULE_ALIAS_CRYPTO("hmac");
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Cryptographic API.
	3	*
	4	* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
	5	*
	6	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
0796ae06	7	* Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
1da177e4 LT	8	*
	9	* The HMAC implementation is derived from USAGI.
	10	* Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
	11	*
	12	* This program is free software; you can redistribute it and/or modify it
	13	* under the terms of the GNU General Public License as published by the Free
0796ae06	14	* Software Foundation; either version 2 of the License, or (at your option)
1da177e4 LT	15	* any later version.
	16	*
	17	*/
0796ae06	18
5f7082ed	19	#include <crypto/internal/hash.h>
b2ab4a57	20	#include <crypto/scatterwalk.h>
0796ae06 HX	21	#include <linux/err.h>
	22	#include <linux/init.h>
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
378f058c	25	#include <linux/scatterlist.h>
0796ae06 HX	26	#include <linux/string.h>
	27
	28	struct hmac_ctx {
0b767b4d	29	struct crypto_shash *hash;
0796ae06	30	};
1da177e4	31
0796ae06 HX	32	static inline void align_ptr(void p, unsigned int align)
	33	{
	34	return (void *)ALIGN((unsigned long)p, align);
	35	}
	36
8bd1209c	37	static inline struct hmac_ctx hmac_ctx(struct crypto_shash tfm)
0796ae06	38	{
8bd1209c	39	return align_ptr(crypto_shash_ctx_aligned(tfm) +
0b767b4d	40	crypto_shash_statesize(tfm) * 2,
8bd1209c	41	crypto_tfm_ctx_alignment());
0796ae06 HX	42	}
0796ae06 HX	43
8bd1209c	44	static int hmac_setkey(struct crypto_shash *parent,
0796ae06 HX	45	const u8 *inkey, unsigned int keylen)
0796ae06 HX	46	{
8bd1209c HX	47	int bs = crypto_shash_blocksize(parent);
8bd1209c HX	48	int ds = crypto_shash_digestsize(parent);
0b767b4d	49	int ss = crypto_shash_statesize(parent);
8bd1209c	50	char *ipad = crypto_shash_ctx_aligned(parent);
0b767b4d HX	51	char *opad = ipad + ss;
0b767b4d HX	52	struct hmac_ctx *ctx = align_ptr(opad + ss,
8bd1209c	53	crypto_tfm_ctx_alignment());
0b767b4d	54	struct crypto_shash *hash = ctx->hash;
ffb32e97	55	SHASH_DESC_ON_STACK(shash, hash);
0796ae06 HX	56	unsigned int i;
0796ae06 HX	57
ffb32e97 JSM	58	shash->tfm = hash;
	59	shash->flags = crypto_shash_get_flags(parent)
	60	& CRYPTO_TFM_REQ_MAY_SLEEP;
0b767b4d	61
0796ae06	62	if (keylen > bs) {
0796ae06 HX	63	int err;
0796ae06 HX	64
ffb32e97	65	err = crypto_shash_digest(shash, inkey, keylen, ipad);
0796ae06 HX	66	if (err)
	67	return err;
	68
0796ae06	69	keylen = ds;
0b767b4d HX	70	} else
0b767b4d HX	71	memcpy(ipad, inkey, keylen);
0796ae06	72
0796ae06 HX	73	memset(ipad + keylen, 0, bs - keylen);
	74	memcpy(opad, ipad, bs);
	75
	76	for (i = 0; i < bs; i++) {
	77	ipad[i] ^= 0x36;
	78	opad[i] ^= 0x5c;
	79	}
	80
ffb32e97 JSM	81	return crypto_shash_init(shash) ?:
	82	crypto_shash_update(shash, ipad, bs) ?:
	83	crypto_shash_export(shash, ipad) ?:
	84	crypto_shash_init(shash) ?:
	85	crypto_shash_update(shash, opad, bs) ?:
	86	crypto_shash_export(shash, opad);
0796ae06 HX	87	}
0796ae06 HX	88
0b767b4d HX	89	static int hmac_export(struct shash_desc pdesc, void out)
	90	{
	91	struct shash_desc *desc = shash_desc_ctx(pdesc);
	92
	93	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	94
	95	return crypto_shash_export(desc, out);
	96	}
	97
	98	static int hmac_import(struct shash_desc pdesc, const void in)
0796ae06	99	{
8bd1209c	100	struct shash_desc *desc = shash_desc_ctx(pdesc);
0b767b4d	101	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
8bd1209c	102
0b767b4d	103	desc->tfm = ctx->hash;
8bd1209c HX	104	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
8bd1209c HX	105
0b767b4d HX	106	return crypto_shash_import(desc, in);
	107	}
	108
	109	static int hmac_init(struct shash_desc *pdesc)
	110	{
	111	return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
0796ae06 HX	112	}
0796ae06 HX	113
8bd1209c HX	114	static int hmac_update(struct shash_desc *pdesc,
8bd1209c HX	115	const u8 *data, unsigned int nbytes)
0796ae06	116	{
8bd1209c	117	struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06	118
8bd1209c	119	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06	120
8bd1209c	121	return crypto_shash_update(desc, data, nbytes);
0796ae06 HX	122	}
0796ae06 HX	123
8bd1209c	124	static int hmac_final(struct shash_desc pdesc, u8 out)
0796ae06	125	{
8bd1209c	126	struct crypto_shash *parent = pdesc->tfm;
8bd1209c	127	int ds = crypto_shash_digestsize(parent);
0b767b4d HX	128	int ss = crypto_shash_statesize(parent);
0b767b4d HX	129	char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c	130	struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06	131
8bd1209c	132	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
73af07de	133
0b767b4d HX	134	return crypto_shash_final(desc, out) ?:
	135	crypto_shash_import(desc, opad) ?:
	136	crypto_shash_finup(desc, out, ds, out);
0796ae06 HX	137	}
0796ae06 HX	138
8bd1209c HX	139	static int hmac_finup(struct shash_desc pdesc, const u8 data,
8bd1209c HX	140	unsigned int nbytes, u8 *out)
0796ae06	141	{
0796ae06	142
8bd1209c	143	struct crypto_shash *parent = pdesc->tfm;
8bd1209c	144	int ds = crypto_shash_digestsize(parent);
0b767b4d HX	145	int ss = crypto_shash_statesize(parent);
0b767b4d HX	146	char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c	147	struct shash_desc *desc = shash_desc_ctx(pdesc);
78c2f0b8	148
8bd1209c	149	desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06	150
0b767b4d HX	151	return crypto_shash_finup(desc, data, nbytes, out) ?:
	152	crypto_shash_import(desc, opad) ?:
	153	crypto_shash_finup(desc, out, ds, out);
0796ae06 HX	154	}
	155
	156	static int hmac_init_tfm(struct crypto_tfm *tfm)
	157	{
8bd1209c HX	158	struct crypto_shash *parent = __crypto_shash_cast(tfm);
8bd1209c HX	159	struct crypto_shash *hash;
0796ae06	160	struct crypto_instance inst = (void )tfm->__crt_alg;
8bd1209c HX	161	struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
8bd1209c HX	162	struct hmac_ctx *ctx = hmac_ctx(parent);
0796ae06	163
8bd1209c	164	hash = crypto_spawn_shash(spawn);
2e306ee0 HX	165	if (IS_ERR(hash))
2e306ee0 HX	166	return PTR_ERR(hash);
0796ae06	167
8bd1209c HX	168	parent->descsize = sizeof(struct shash_desc) +
	169	crypto_shash_descsize(hash);
	170
0b767b4d	171	ctx->hash = hash;
0796ae06 HX	172	return 0;
	173	}
	174
	175	static void hmac_exit_tfm(struct crypto_tfm *tfm)
	176	{
8bd1209c	177	struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
0b767b4d	178	crypto_free_shash(ctx->hash);
0796ae06 HX	179	}
0796ae06 HX	180
8bd1209c	181	static int hmac_create(struct crypto_template tmpl, struct rtattr *tb)
0796ae06	182	{
8bd1209c	183	struct shash_instance *inst;
0796ae06	184	struct crypto_alg *alg;
8bd1209c	185	struct shash_alg *salg;
ebc610e5	186	int err;
ca786dc7	187	int ds;
0b767b4d	188	int ss;
ebc610e5	189
8bd1209c	190	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
ebc610e5	191	if (err)
8bd1209c HX	192	return err;
	193
	194	salg = shash_attr_alg(tb[1], 0, 0);
	195	if (IS_ERR(salg))
	196	return PTR_ERR(salg);
	197
	198	err = -EINVAL;
	199	ds = salg->digestsize;
0b767b4d	200	ss = salg->statesize;
8bd1209c	201	alg = &salg->base;
0b767b4d HX	202	if (ds > alg->cra_blocksize \|\|
0b767b4d HX	203	ss < alg->cra_blocksize)
ca786dc7 HX	204	goto out_put_alg;
ca786dc7 HX	205
8bd1209c	206	inst = shash_alloc_instance("hmac", alg);
3b3fc322	207	err = PTR_ERR(inst);
0796ae06 HX	208	if (IS_ERR(inst))
	209	goto out_put_alg;
	210
8bd1209c HX	211	err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
	212	shash_crypto_instance(inst));
	213	if (err)
	214	goto out_free_inst;
	215
	216	inst->alg.base.cra_priority = alg->cra_priority;
	217	inst->alg.base.cra_blocksize = alg->cra_blocksize;
	218	inst->alg.base.cra_alignmask = alg->cra_alignmask;
0796ae06	219
0b767b4d	220	ss = ALIGN(ss, alg->cra_alignmask + 1);
8bd1209c	221	inst->alg.digestsize = ds;
0b767b4d	222	inst->alg.statesize = ss;
0796ae06	223
8bd1209c	224	inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
0b767b4d	225	ALIGN(ss * 2, crypto_tfm_ctx_alignment());
0796ae06	226
8bd1209c HX	227	inst->alg.base.cra_init = hmac_init_tfm;
8bd1209c HX	228	inst->alg.base.cra_exit = hmac_exit_tfm;
0796ae06	229
8bd1209c HX	230	inst->alg.init = hmac_init;
	231	inst->alg.update = hmac_update;
	232	inst->alg.final = hmac_final;
	233	inst->alg.finup = hmac_finup;
0b767b4d HX	234	inst->alg.export = hmac_export;
0b767b4d HX	235	inst->alg.import = hmac_import;
8bd1209c HX	236	inst->alg.setkey = hmac_setkey;
	237
	238	err = shash_register_instance(tmpl, inst);
	239	if (err) {
	240	out_free_inst:
	241	shash_free_instance(shash_crypto_instance(inst));
	242	}
0796ae06 HX	243
	244	out_put_alg:
	245	crypto_mod_put(alg);
8bd1209c	246	return err;
0796ae06 HX	247	}
	248
	249	static struct crypto_template hmac_tmpl = {
	250	.name = "hmac",
8bd1209c HX	251	.create = hmac_create,
8bd1209c HX	252	.free = shash_free_instance,
0796ae06 HX	253	.module = THIS_MODULE,
	254	};
	255
	256	static int __init hmac_module_init(void)
	257	{
	258	return crypto_register_template(&hmac_tmpl);
	259	}
	260
	261	static void __exit hmac_module_exit(void)
	262	{
	263	crypto_unregister_template(&hmac_tmpl);
	264	}
	265
	266	module_init(hmac_module_init);
	267	module_exit(hmac_module_exit);
	268
	269	MODULE_LICENSE("GPL");
	270	MODULE_DESCRIPTION("HMAC hash algorithm");
4943ba16	271	MODULE_ALIAS_CRYPTO("hmac");