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/*
* Cryptographic API.
*
* HMAC: Keyed-Hashing for Message Authentication (RFC2104).
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.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 <linux/crypto.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/scatterlist.h>
#include "internal.h"
static void hash_key(struct crypto_tfm *tfm, u8 *key, unsigned int keylen)
{
struct scatterlist tmp;
sg_set_buf(&tmp, key, keylen);
crypto_digest_digest(tfm, &tmp, 1, key);
}
int crypto_alloc_hmac_block(struct crypto_tfm *tfm)
{
int ret = 0;
BUG_ON(!crypto_tfm_alg_blocksize(tfm));
tfm->crt_digest.dit_hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
GFP_KERNEL);
if (tfm->crt_digest.dit_hmac_block == NULL)
ret = -ENOMEM;
return ret;
}
void crypto_free_hmac_block(struct crypto_tfm *tfm)
{
kfree(tfm->crt_digest.dit_hmac_block);
}
void crypto_hmac_init(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen)
{
unsigned int i;
struct scatterlist tmp;
char *ipad = tfm->crt_digest.dit_hmac_block;
if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
hash_key(tfm, key, *keylen);
*keylen = crypto_tfm_alg_digestsize(tfm);
}
memset(ipad, 0, crypto_tfm_alg_blocksize(tfm));
memcpy(ipad, key, *keylen);
for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
ipad[i] ^= 0x36;
sg_set_buf(&tmp, ipad, crypto_tfm_alg_blocksize(tfm));
crypto_digest_init(tfm);
crypto_digest_update(tfm, &tmp, 1);
}
void crypto_hmac_update(struct crypto_tfm *tfm,
struct scatterlist *sg, unsigned int nsg)
{
crypto_digest_update(tfm, sg, nsg);
}
void crypto_hmac_final(struct crypto_tfm *tfm, u8 *key,
unsigned int *keylen, u8 *out)
{
unsigned int i;
struct scatterlist tmp;
char *opad = tfm->crt_digest.dit_hmac_block;
if (*keylen > crypto_tfm_alg_blocksize(tfm)) {
hash_key(tfm, key, *keylen);
*keylen = crypto_tfm_alg_digestsize(tfm);
}
crypto_digest_final(tfm, out);
memset(opad, 0, crypto_tfm_alg_blocksize(tfm));
memcpy(opad, key, *keylen);
for (i = 0; i < crypto_tfm_alg_blocksize(tfm); i++)
opad[i] ^= 0x5c;
sg_set_buf(&tmp, opad, crypto_tfm_alg_blocksize(tfm));
crypto_digest_init(tfm);
crypto_digest_update(tfm, &tmp, 1);
sg_set_buf(&tmp, out, crypto_tfm_alg_digestsize(tfm));
crypto_digest_update(tfm, &tmp, 1);
crypto_digest_final(tfm, out);
}
void crypto_hmac(struct crypto_tfm *tfm, u8 *key, unsigned int *keylen,
struct scatterlist *sg, unsigned int nsg, u8 *out)
{
crypto_hmac_init(tfm, key, keylen);
crypto_hmac_update(tfm, sg, nsg);
crypto_hmac_final(tfm, key, keylen, out);
}
EXPORT_SYMBOL_GPL(crypto_hmac_init);
EXPORT_SYMBOL_GPL(crypto_hmac_update);
EXPORT_SYMBOL_GPL(crypto_hmac_final);
EXPORT_SYMBOL_GPL(crypto_hmac);
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