[linux-2.6-block.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/algapi.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/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 tmplen;
		int err;

		desc.tfm = tfm;
		desc.flags = crypto_hash_get_flags(parent);
		desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;

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

		tmplen = bs * 2 + ds;
		sg_init_one(&tmp, ipad, tmplen);

		for (; keylen > tmplen; inkey += tmplen, keylen -= tmplen) {
			memcpy(ipad, inkey, tmplen);
			err = crypto_hash_update(&desc, &tmp, tmplen);
			if (err)
				return err;
		}

		if (keylen) {
			memcpy(ipad, inkey, keylen);
			err = crypto_hash_update(&desc, &tmp, keylen);
			if (err)
				return err;
		}

		err = crypto_hash_final(&desc, 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_init_one(&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_init_one(&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_init_table(sg1, 2);
	sg_set_buf(sg1, ipad, bs);
	scatterwalk_sg_chain(sg1, 2, sg);

	sg_init_table(sg2, 1);
	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;
	int ds;

	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_CAST(alg);

	inst = ERR_PTR(-EINVAL);
	ds = (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
	     CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
				    alg->cra_digest.dia_digestsize;
	if (ds > alg->cra_blocksize)
		goto out_put_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 = ds;

	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
				ALIGN(inst->alg.cra_blocksize * 2 + ds,
				      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 <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 HX	18
0796ae06 HX	19	#include <crypto/algapi.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/slab.h>
	27	#include <linux/string.h>
	28
	29	struct hmac_ctx {
	30	struct crypto_hash *child;
	31	};
1da177e4	32
0796ae06 HX	33	static inline void align_ptr(void p, unsigned int align)
	34	{
	35	return (void *)ALIGN((unsigned long)p, align);
	36	}
	37
	38	static inline struct hmac_ctx hmac_ctx(struct crypto_hash tfm)
	39	{
	40	return align_ptr(crypto_hash_ctx_aligned(tfm) +
	41	crypto_hash_blocksize(tfm) * 2 +
	42	crypto_hash_digestsize(tfm), sizeof(void *));
	43	}
	44
	45	static int hmac_setkey(struct crypto_hash *parent,
	46	const u8 *inkey, unsigned int keylen)
	47	{
	48	int bs = crypto_hash_blocksize(parent);
	49	int ds = crypto_hash_digestsize(parent);
	50	char *ipad = crypto_hash_ctx_aligned(parent);
	51	char *opad = ipad + bs;
	52	char *digest = opad + bs;
	53	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	54	struct crypto_hash *tfm = ctx->child;
	55	unsigned int i;
	56
	57	if (keylen > bs) {
	58	struct hash_desc desc;
	59	struct scatterlist tmp;
67412f0e	60	int tmplen;
0796ae06 HX	61	int err;
	62
	63	desc.tfm = tfm;
	64	desc.flags = crypto_hash_get_flags(parent);
	65	desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06	66
67412f0e HX	67	err = crypto_hash_init(&desc);
	68	if (err)
	69	return err;
	70
	71	tmplen = bs * 2 + ds;
	72	sg_init_one(&tmp, ipad, tmplen);
	73
	74	for (; keylen > tmplen; inkey += tmplen, keylen -= tmplen) {
	75	memcpy(ipad, inkey, tmplen);
	76	err = crypto_hash_update(&desc, &tmp, tmplen);
	77	if (err)
	78	return err;
	79	}
	80
	81	if (keylen) {
	82	memcpy(ipad, inkey, keylen);
	83	err = crypto_hash_update(&desc, &tmp, keylen);
	84	if (err)
	85	return err;
	86	}
	87
	88	err = crypto_hash_final(&desc, digest);
0796ae06 HX	89	if (err)
	90	return err;
	91
	92	inkey = digest;
	93	keylen = ds;
	94	}
	95
	96	memcpy(ipad, inkey, keylen);
	97	memset(ipad + keylen, 0, bs - keylen);
	98	memcpy(opad, ipad, bs);
	99
	100	for (i = 0; i < bs; i++) {
	101	ipad[i] ^= 0x36;
	102	opad[i] ^= 0x5c;
	103	}
	104
	105	return 0;
	106	}
	107
	108	static int hmac_init(struct hash_desc *pdesc)
	109	{
	110	struct crypto_hash *parent = pdesc->tfm;
	111	int bs = crypto_hash_blocksize(parent);
	112	int ds = crypto_hash_digestsize(parent);
	113	char *ipad = crypto_hash_ctx_aligned(parent);
	114	struct hmac_ctx ctx = align_ptr(ipad + bs 2 + ds, sizeof(void *));
	115	struct hash_desc desc;
	116	struct scatterlist tmp;
73af07de	117	int err;
0796ae06 HX	118
	119	desc.tfm = ctx->child;
	120	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
a6767721	121	sg_init_one(&tmp, ipad, bs);
0796ae06	122
73af07de HX	123	err = crypto_hash_init(&desc);
	124	if (unlikely(err))
	125	return err;
	126
	127	return crypto_hash_update(&desc, &tmp, bs);
0796ae06 HX	128	}
	129
	130	static int hmac_update(struct hash_desc *pdesc,
	131	struct scatterlist *sg, unsigned int nbytes)
	132	{
	133	struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
	134	struct hash_desc desc;
	135
	136	desc.tfm = ctx->child;
	137	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	138
	139	return crypto_hash_update(&desc, sg, nbytes);
	140	}
	141
	142	static int hmac_final(struct hash_desc pdesc, u8 out)
	143	{
	144	struct crypto_hash *parent = pdesc->tfm;
	145	int bs = crypto_hash_blocksize(parent);
	146	int ds = crypto_hash_digestsize(parent);
	147	char *opad = crypto_hash_ctx_aligned(parent) + bs;
	148	char *digest = opad + bs;
	149	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	150	struct hash_desc desc;
	151	struct scatterlist tmp;
73af07de	152	int err;
0796ae06 HX	153
	154	desc.tfm = ctx->child;
	155	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
a6767721	156	sg_init_one(&tmp, opad, bs + ds);
0796ae06	157
73af07de HX	158	err = crypto_hash_final(&desc, digest);
	159	if (unlikely(err))
	160	return err;
	161
	162	return crypto_hash_digest(&desc, &tmp, bs + ds, out);
0796ae06 HX	163	}
	164
	165	static int hmac_digest(struct hash_desc pdesc, struct scatterlist sg,
	166	unsigned int nbytes, u8 *out)
	167	{
	168	struct crypto_hash *parent = pdesc->tfm;
	169	int bs = crypto_hash_blocksize(parent);
	170	int ds = crypto_hash_digestsize(parent);
	171	char *ipad = crypto_hash_ctx_aligned(parent);
	172	char *opad = ipad + bs;
	173	char *digest = opad + bs;
	174	struct hmac_ctx ctx = align_ptr(digest + ds, sizeof(void ));
	175	struct hash_desc desc;
	176	struct scatterlist sg1[2];
	177	struct scatterlist sg2[1];
73af07de	178	int err;
0796ae06 HX	179
	180	desc.tfm = ctx->child;
	181	desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
	182
41fb2854	183	sg_init_table(sg1, 2);
0796ae06	184	sg_set_buf(sg1, ipad, bs);
b2ab4a57	185	scatterwalk_sg_chain(sg1, 2, sg);
78c2f0b8	186
41fb2854	187	sg_init_table(sg2, 1);
0796ae06 HX	188	sg_set_buf(sg2, opad, bs + ds);
0796ae06 HX	189
73af07de HX	190	err = crypto_hash_digest(&desc, sg1, nbytes + bs, digest);
	191	if (unlikely(err))
	192	return err;
	193
	194	return crypto_hash_digest(&desc, sg2, bs + ds, out);
0796ae06 HX	195	}
	196
	197	static int hmac_init_tfm(struct crypto_tfm *tfm)
	198	{
2e306ee0	199	struct crypto_hash *hash;
0796ae06 HX	200	struct crypto_instance inst = (void )tfm->__crt_alg;
	201	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
	202	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	203
2e306ee0 HX	204	hash = crypto_spawn_hash(spawn);
	205	if (IS_ERR(hash))
	206	return PTR_ERR(hash);
0796ae06	207
2e306ee0	208	ctx->child = hash;
0796ae06 HX	209	return 0;
	210	}
	211
	212	static void hmac_exit_tfm(struct crypto_tfm *tfm)
	213	{
	214	struct hmac_ctx *ctx = hmac_ctx(__crypto_hash_cast(tfm));
	215	crypto_free_hash(ctx->child);
	216	}
	217
	218	static void hmac_free(struct crypto_instance *inst)
	219	{
	220	crypto_drop_spawn(crypto_instance_ctx(inst));
	221	kfree(inst);
	222	}
	223
ebc610e5	224	static struct crypto_instance hmac_alloc(struct rtattr *tb)
0796ae06 HX	225	{
	226	struct crypto_instance *inst;
	227	struct crypto_alg *alg;
ebc610e5	228	int err;
ca786dc7	229	int ds;
ebc610e5 HX	230
	231	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
	232	if (err)
	233	return ERR_PTR(err);
0796ae06	234
ebc610e5 HX	235	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_HASH,
ebc610e5 HX	236	CRYPTO_ALG_TYPE_HASH_MASK);
0796ae06	237	if (IS_ERR(alg))
e231c2ee	238	return ERR_CAST(alg);
0796ae06	239
ca786dc7 HX	240	inst = ERR_PTR(-EINVAL);
	241	ds = (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
	242	CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
	243	alg->cra_digest.dia_digestsize;
	244	if (ds > alg->cra_blocksize)
	245	goto out_put_alg;
	246
0796ae06 HX	247	inst = crypto_alloc_instance("hmac", alg);
	248	if (IS_ERR(inst))
	249	goto out_put_alg;
	250
	251	inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
	252	inst->alg.cra_priority = alg->cra_priority;
	253	inst->alg.cra_blocksize = alg->cra_blocksize;
	254	inst->alg.cra_alignmask = alg->cra_alignmask;
	255	inst->alg.cra_type = &crypto_hash_type;
	256
ca786dc7	257	inst->alg.cra_hash.digestsize = ds;
0796ae06 HX	258
0796ae06 HX	259	inst->alg.cra_ctxsize = sizeof(struct hmac_ctx) +
ca786dc7	260	ALIGN(inst->alg.cra_blocksize * 2 + ds,
0796ae06 HX	261	sizeof(void *));
	262
	263	inst->alg.cra_init = hmac_init_tfm;
	264	inst->alg.cra_exit = hmac_exit_tfm;
	265
	266	inst->alg.cra_hash.init = hmac_init;
	267	inst->alg.cra_hash.update = hmac_update;
	268	inst->alg.cra_hash.final = hmac_final;
	269	inst->alg.cra_hash.digest = hmac_digest;
	270	inst->alg.cra_hash.setkey = hmac_setkey;
	271
	272	out_put_alg:
	273	crypto_mod_put(alg);
	274	return inst;
	275	}
	276
	277	static struct crypto_template hmac_tmpl = {
	278	.name = "hmac",
	279	.alloc = hmac_alloc,
	280	.free = hmac_free,
	281	.module = THIS_MODULE,
	282	};
	283
	284	static int __init hmac_module_init(void)
	285	{
	286	return crypto_register_template(&hmac_tmpl);
	287	}
	288
	289	static void __exit hmac_module_exit(void)
	290	{
	291	crypto_unregister_template(&hmac_tmpl);
	292	}
	293
	294	module_init(hmac_module_init);
	295	module_exit(hmac_module_exit);
	296
	297	MODULE_LICENSE("GPL");
	298	MODULE_DESCRIPTION("HMAC hash algorithm");