linux/crypto/hmac.c
Herbert Xu 055bcee310 [CRYPTO] digest: Added user API for new hash type
The existing digest user interface is inadequate for support asynchronous
operations.  For one it doesn't return a value to indicate success or
failure, nor does it take a per-operation descriptor which is essential
for the issuing of requests while other requests are still outstanding.

This patch is the first in a series of steps to remodel the interface
for asynchronous operations.

For the ease of transition the new interface will be known as "hash"
while the old one will remain as "digest".

This patch also changes sg_next to allow chaining.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2006-09-21 11:46:17 +10:00

125 lines
3.1 KiB
C

/*
* 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_hash.hmac_block = kmalloc(crypto_tfm_alg_blocksize(tfm),
GFP_KERNEL);
if (tfm->crt_hash.hmac_block == NULL)
ret = -ENOMEM;
return ret;
}
void crypto_free_hmac_block(struct crypto_tfm *tfm)
{
kfree(tfm->crt_hash.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_hash.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_hash.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);