[linux.git] / crypto / hmac.c

/*
 * Cryptographic API.
 *
 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
 *
 * Copyright (c) 2002 James Morris <[email protected]>
 * Copyright (c) 2006 Herbert Xu <[email protected]>
 *
 * The HMAC implementation is derived from USAGI.
 * Copyright (c) 2002 Kazunori Miyazawa <[email protected]> / 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/algapi.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/string.h>

struct hmac_ctx {
	struct crypto_hash *child;
};

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_hash *tfm)
{
	return align_ptr(crypto_hash_ctx_aligned(tfm) +
			 crypto_hash_blocksize(tfm) * 2 +
			 crypto_hash_digestsize(tfm), sizeof(void *));
}

static int hmac_setkey(struct crypto_hash *parent,
		       const u8 *inkey, unsigned int keylen)
{
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	char *opad = ipad + bs;
	char *digest = opad + bs;
	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
	struct crypto_hash *tfm = ctx->child;
	unsigned int i;

	if (keylen > bs) {
		struct hash_desc desc;
		struct scatterlist tmp;
		int err;

		desc.tfm = tfm;
		desc.flags = crypto_hash_get_flags(parent);
		desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
		sg_set_buf(&tmp, inkey, keylen);

		err = crypto_hash_digest(&desc, &tmp, keylen, digest);
		if (err)
			return err;

		inkey = digest;
		keylen = ds;
	}

	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 0;
}

static int hmac_init(struct hash_desc *pdesc)
{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	struct hmac_ctx *ctx = align_ptr(ipad + bs * 2 + ds, sizeof(void *));
	struct hash_desc desc;
	struct scatterlist tmp;
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	sg_set_buf(&tmp, ipad, bs);

	err = crypto_hash_init(&desc);
	if (unlikely(err))
		return err;

	return crypto_hash_update(&desc, &tmp, bs);
}

static int hmac_update(struct hash_desc *pdesc,
		       struct scatterlist *sg, unsigned int nbytes)
{
	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
	struct hash_desc desc;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	return crypto_hash_update(&desc, sg, nbytes);
}

static int hmac_final(struct hash_desc *pdesc, u8 *out)
{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *opad = crypto_hash_ctx_aligned(parent) + bs;
	char *digest = opad + bs;
	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
	struct hash_desc desc;
	struct scatterlist tmp;
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	sg_set_buf(&tmp, opad, bs + ds);

	err = crypto_hash_final(&desc, digest);
	if (unlikely(err))
		return err;

	return crypto_hash_digest(&desc, &tmp, bs + ds, out);
}

static int hmac_digest(struct hash_desc *pdesc, struct scatterlist *sg,
		       unsigned int nbytes, u8 *out)
{
	struct crypto_hash *parent = pdesc->tfm;
	int bs = crypto_hash_blocksize(parent);
	int ds = crypto_hash_digestsize(parent);
	char *ipad = crypto_hash_ctx_aligned(parent);
	char *opad = ipad + bs;
	char *digest = opad + bs;
	struct hmac_ctx *ctx = align_ptr(digest + ds, sizeof(void *));
	struct hash_desc desc;
	struct scatterlist sg1[2];
	struct scatterlist sg2[1];
	int err;

	desc.tfm = ctx->child;
	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;

	sg_set_buf(sg1, ipad, bs);
	sg1[1].page = (void *)sg;
	sg1[1].length = 0;
	sg_set_buf(sg2, opad, bs + ds);

	err = crypto_hash_digest(&desc, sg1, nbytes + bs, digest);
	if (unlikely(err))
		return err;

	return crypto_hash_digest(&desc, sg2, bs + ds, out);
}

static int hmac_init_tfm(struct crypto_tfm *tfm)
{
	struct crypto_hash *hash;
	struct crypto_instance *inst = (void *)tfm->__crt_alg;
	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));

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

	ctx->child = hash;
	return 0;
}

static void hmac_exit_tfm(struct crypto_tfm *tfm)
{
	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	crypto_free_hash(ctx->child);
}

static void hmac_free(struct crypto_instance *inst)
{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(inst);
}

static struct crypto_instance *hmac_alloc(struct rtattr **tb)
{
	struct crypto_instance *inst;
	struct crypto_alg *alg;
	int err;

	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	if (err)
		return ERR_PTR(err);

	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_HASH,
				  CRYPTO_ALG_TYPE_HASH_MASK);
	if (IS_ERR(alg))
		return ERR_PTR(PTR_ERR(alg));

	inst = crypto_alloc_instance("hmac", alg);
	if (IS_ERR(inst))
		goto out_put_alg;

	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	inst->alg.cra_priority = alg->cra_priority;
	inst->alg.cra_blocksize = alg->cra_blocksize;
	inst->alg.cra_alignmask = alg->cra_alignmask;
	inst->alg.cra_type = &crypto_hash_type;

	inst->alg.cra_hash.digestsize =
		(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
		CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
				       alg->cra_digest.dia_digestsize;

	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
				ALIGN(inst->alg.cra_blocksize * 2 +
				      inst->alg.cra_hash.digestsize,
				      sizeof(void *));

	inst->alg.cra_init = hmac_init_tfm;
	inst->alg.cra_exit = hmac_exit_tfm;

	inst->alg.cra_hash.init = hmac_init;
	inst->alg.cra_hash.update = hmac_update;
	inst->alg.cra_hash.final = hmac_final;
	inst->alg.cra_hash.digest = hmac_digest;
	inst->alg.cra_hash.setkey = hmac_setkey;

out_put_alg:
	crypto_mod_put(alg);
	return inst;
}

static struct crypto_template hmac_tmpl = {
	.name = "hmac",
	.alloc = hmac_alloc,
	.free = hmac_free,
	.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");
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 <[email protected]>
0796ae06	7	* Copyright (c) 2006 Herbert Xu <[email protected]>
1da177e4 LT	8	*
	9	* The HMAC implementation is derived from USAGI.
	10	* Copyright (c) 2002 Kazunori Miyazawa <[email protected]> / 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 HX	18
	19	#include <crypto/algapi.h>
	20	#include <linux/err.h>
	21	#include <linux/init.h>
	22	#include <linux/kernel.h>
	23	#include <linux/module.h>
378f058c	24	#include <linux/scatterlist.h>
0796ae06 HX	25	#include <linux/slab.h>
	26	#include <linux/string.h>
	27
	28	struct hmac_ctx {
	29	struct crypto_hash *child;
	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
	37	static inline struct hmac_ctx hmac_ctx(struct crypto_hash tfm)
	38	{
	39	return align_ptr(crypto_hash_ctx_aligned(tfm) +
	40	crypto_hash_blocksize(tfm) * 2 +
	41	crypto_hash_digestsize(tfm), sizeof(void *));
	42	}
	43
	44	static int hmac_setkey(struct crypto_hash *parent,
	45	const u8 *inkey, unsigned int keylen)
	46	{
	47	int bs = crypto_hash_blocksize(parent);
	48	int ds = crypto_hash_digestsize(parent);
	49	char *ipad = crypto_hash_ctx_aligned(parent);
	50	char *opad = ipad + bs;
	51	char *digest = opad + bs;
	52	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	53	struct crypto_hash *tfm = ctx->child;
	54	unsigned int i;
	55
	56	if (keylen > bs) {
	57	struct hash_desc desc;
	58	struct scatterlist tmp;
	59	int err;
	60
	61	desc.tfm = tfm;
	62	desc.flags = crypto_hash_get_flags(parent);
	63	desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
	64	sg_set_buf(&tmp, inkey, keylen);
	65
	66	err = crypto_hash_digest(&desc, &tmp, keylen, digest);
	67	if (err)
	68	return err;
	69
	70	inkey = digest;
	71	keylen = ds;
	72	}
	73
	74	memcpy(ipad, inkey, keylen);
	75	memset(ipad + keylen, 0, bs - keylen);
	76	memcpy(opad, ipad, bs);
	77
	78	for (i = 0; i < bs; i++) {
	79	ipad[i] ^= 0x36;
	80	opad[i] ^= 0x5c;
	81	}
	82
	83	return 0;
	84	}
	85
	86	static int hmac_init(struct hash_desc *pdesc)
	87	{
	88	struct crypto_hash *parent = pdesc->tfm;
	89	int bs = crypto_hash_blocksize(parent);
	90	int ds = crypto_hash_digestsize(parent);
	91	char *ipad = crypto_hash_ctx_aligned(parent);
	92	struct hmac_ctx ctx = align_ptr(ipad + bs 2 + ds, sizeof(void *));
	93	struct hash_desc desc;
	94	struct scatterlist tmp;
73af07de	95	int err;
0796ae06 HX	96
	97	desc.tfm = ctx->child;
	98	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	99	sg_set_buf(&tmp, ipad, bs);
	100
73af07de HX	101	err = crypto_hash_init(&desc);
	102	if (unlikely(err))
	103	return err;
	104
	105	return crypto_hash_update(&desc, &tmp, bs);
0796ae06 HX	106	}
	107
	108	static int hmac_update(struct hash_desc *pdesc,
	109	struct scatterlist *sg, unsigned int nbytes)
	110	{
	111	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
	112	struct hash_desc desc;
	113
	114	desc.tfm = ctx->child;
	115	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	116
	117	return crypto_hash_update(&desc, sg, nbytes);
	118	}
	119
	120	static int hmac_final(struct hash_desc pdesc, u8 out)
	121	{
	122	struct crypto_hash *parent = pdesc->tfm;
	123	int bs = crypto_hash_blocksize(parent);
	124	int ds = crypto_hash_digestsize(parent);
	125	char *opad = crypto_hash_ctx_aligned(parent) + bs;
	126	char *digest = opad + bs;
	127	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	128	struct hash_desc desc;
	129	struct scatterlist tmp;
73af07de	130	int err;
0796ae06 HX	131
	132	desc.tfm = ctx->child;
	133	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	134	sg_set_buf(&tmp, opad, bs + ds);
	135
73af07de HX	136	err = crypto_hash_final(&desc, digest);
	137	if (unlikely(err))
	138	return err;
	139
	140	return crypto_hash_digest(&desc, &tmp, bs + ds, out);
0796ae06 HX	141	}
	142
	143	static int hmac_digest(struct hash_desc pdesc, struct scatterlist sg,
	144	unsigned int nbytes, u8 *out)
	145	{
	146	struct crypto_hash *parent = pdesc->tfm;
	147	int bs = crypto_hash_blocksize(parent);
	148	int ds = crypto_hash_digestsize(parent);
	149	char *ipad = crypto_hash_ctx_aligned(parent);
	150	char *opad = ipad + bs;
	151	char *digest = opad + bs;
	152	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	153	struct hash_desc desc;
	154	struct scatterlist sg1[2];
	155	struct scatterlist sg2[1];
73af07de	156	int err;
0796ae06 HX	157
	158	desc.tfm = ctx->child;
	159	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	160
	161	sg_set_buf(sg1, ipad, bs);
	162	sg1[1].page = (void *)sg;
	163	sg1[1].length = 0;
	164	sg_set_buf(sg2, opad, bs + ds);
	165
73af07de HX	166	err = crypto_hash_digest(&desc, sg1, nbytes + bs, digest);
	167	if (unlikely(err))
	168	return err;
	169
	170	return crypto_hash_digest(&desc, sg2, bs + ds, out);
0796ae06 HX	171	}
	172
	173	static int hmac_init_tfm(struct crypto_tfm *tfm)
	174	{
2e306ee0	175	struct crypto_hash *hash;
0796ae06 HX	176	struct crypto_instance inst = (void )tfm->__crt_alg;
	177	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	178	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	179
2e306ee0 HX	180	hash = crypto_spawn_hash(spawn);
	181	if (IS_ERR(hash))
	182	return PTR_ERR(hash);
0796ae06	183
2e306ee0	184	ctx->child = hash;
0796ae06 HX	185	return 0;
	186	}
	187
	188	static void hmac_exit_tfm(struct crypto_tfm *tfm)
	189	{
	190	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	191	crypto_free_hash(ctx->child);
	192	}
	193
	194	static void hmac_free(struct crypto_instance *inst)
	195	{
	196	crypto_drop_spawn(crypto_instance_ctx(inst));
	197	kfree(inst);
	198	}
	199
ebc610e5	200	static struct crypto_instance hmac_alloc(struct rtattr *tb)
0796ae06 HX	201	{
	202	struct crypto_instance *inst;
	203	struct crypto_alg *alg;
ebc610e5 HX	204	int err;
	205
	206	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	207	if (err)
	208	return ERR_PTR(err);
0796ae06	209
ebc610e5 HX	210	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_HASH,
ebc610e5 HX	211	CRYPTO_ALG_TYPE_HASH_MASK);
0796ae06 HX	212	if (IS_ERR(alg))
	213	return ERR_PTR(PTR_ERR(alg));
	214
	215	inst = crypto_alloc_instance("hmac", alg);
	216	if (IS_ERR(inst))
	217	goto out_put_alg;
	218
	219	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	220	inst->alg.cra_priority = alg->cra_priority;
	221	inst->alg.cra_blocksize = alg->cra_blocksize;
	222	inst->alg.cra_alignmask = alg->cra_alignmask;
	223	inst->alg.cra_type = &crypto_hash_type;
	224
	225	inst->alg.cra_hash.digestsize =
	226	(alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
	227	CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
	228	alg->cra_digest.dia_digestsize;
	229
	230	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
	231	ALIGN(inst->alg.cra_blocksize * 2 +
	232	inst->alg.cra_hash.digestsize,
	233	sizeof(void *));
	234
	235	inst->alg.cra_init = hmac_init_tfm;
	236	inst->alg.cra_exit = hmac_exit_tfm;
	237
	238	inst->alg.cra_hash.init = hmac_init;
	239	inst->alg.cra_hash.update = hmac_update;
	240	inst->alg.cra_hash.final = hmac_final;
	241	inst->alg.cra_hash.digest = hmac_digest;
	242	inst->alg.cra_hash.setkey = hmac_setkey;
	243
	244	out_put_alg:
	245	crypto_mod_put(alg);
	246	return inst;
	247	}
	248
	249	static struct crypto_template hmac_tmpl = {
	250	.name = "hmac",
	251	.alloc = hmac_alloc,
	252	.free = hmac_free,
	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");