linux/crypto/digest.c

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/*
* Cryptographic API.
*
* Digest operations.
*
* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
*
* 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/errno.h>
#include <linux/highmem.h>
#include <asm/scatterlist.h>
#include "internal.h"
static void init(struct crypto_tfm *tfm)
{
tfm->__crt_alg->cra_digest.dia_init(tfm);
}
static void update(struct crypto_tfm *tfm,
struct scatterlist *sg, unsigned int nsg)
{
unsigned int i;
unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
for (i = 0; i < nsg; i++) {
struct page *pg = sg[i].page;
unsigned int offset = sg[i].offset;
unsigned int l = sg[i].length;
do {
unsigned int bytes_from_page = min(l, ((unsigned int)
(PAGE_SIZE)) -
offset);
char *src = crypto_kmap(pg, 0);
char *p = src + offset;
if (unlikely(offset & alignmask)) {
unsigned int bytes =
alignmask + 1 - (offset & alignmask);
bytes = min(bytes, bytes_from_page);
tfm->__crt_alg->cra_digest.dia_update(tfm, p,
bytes);
p += bytes;
bytes_from_page -= bytes;
l -= bytes;
}
tfm->__crt_alg->cra_digest.dia_update(tfm, p,
bytes_from_page);
crypto_kunmap(src, 0);
crypto_yield(tfm);
offset = 0;
pg++;
l -= bytes_from_page;
} while (l > 0);
}
}
static void final(struct crypto_tfm *tfm, u8 *out)
{
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
if (unlikely((unsigned long)out & alignmask)) {
unsigned int size = crypto_tfm_alg_digestsize(tfm);
u8 buffer[size + alignmask];
u8 *dst = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
tfm->__crt_alg->cra_digest.dia_final(tfm, dst);
memcpy(out, dst, size);
} else
tfm->__crt_alg->cra_digest.dia_final(tfm, out);
}
static int nosetkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
return -ENOSYS;
}
static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
{
tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
}
static void digest(struct crypto_tfm *tfm,
struct scatterlist *sg, unsigned int nsg, u8 *out)
{
init(tfm);
update(tfm, sg, nsg);
final(tfm, out);
}
int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
{
return flags ? -EINVAL : 0;
}
int crypto_init_digest_ops(struct crypto_tfm *tfm)
{
struct digest_tfm *ops = &tfm->crt_digest;
struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
ops->dit_init = init;
ops->dit_update = update;
ops->dit_final = final;
ops->dit_digest = digest;
ops->dit_setkey = dalg->dia_setkey ? setkey : nosetkey;
return crypto_alloc_hmac_block(tfm);
}
void crypto_exit_digest_ops(struct crypto_tfm *tfm)
{
crypto_free_hmac_block(tfm);
}