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/mm.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include "internal.h"
#include "scatterwalk.h"
static int init(struct hash_desc *desc)
{
struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
tfm->__crt_alg->cra_digest.dia_init(tfm);
return 0;
}
static int update2(struct hash_desc *desc,
struct scatterlist *sg, unsigned int nbytes)
{
struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
if (!nbytes)
return 0;
for (;;) {
struct page *pg = sg_page(sg);
unsigned int offset = sg->offset;
unsigned int l = sg->length;
if (unlikely(l > nbytes))
l = nbytes;
nbytes -= l;
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(desc->flags);
offset = 0;
pg++;
l -= bytes_from_page;
} while (l > 0);
if (!nbytes)
break;
sg = scatterwalk_sg_next(sg);
}
return 0;
}
static int update(struct hash_desc *desc,
struct scatterlist *sg, unsigned int nbytes)
{
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;
return update2(desc, sg, nbytes);
}
static int final(struct hash_desc *desc, u8 *out)
{
struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
if (unlikely((unsigned long)out & alignmask)) {
unsigned long align = alignmask + 1;
unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
u8 *dst = (u8 *)ALIGN(addr, align) +
ALIGN(tfm->__crt_alg->cra_ctxsize, align);
digest->dia_final(tfm, dst);
memcpy(out, dst, digest->dia_digestsize);
} else
digest->dia_final(tfm, out);
return 0;
}
static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
{
crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
return -ENOSYS;
}
static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
{
struct crypto_tfm *tfm = crypto_hash_tfm(hash);
crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
}
static int digest(struct hash_desc *desc,
struct scatterlist *sg, unsigned int nbytes, u8 *out)
{
if (WARN_ON_ONCE(in_irq()))
return -EDEADLK;
init(desc);
update2(desc, sg, nbytes);
return final(desc, out);
}
int crypto_init_digest_ops(struct crypto_tfm *tfm)
{
struct hash_tfm *ops = &tfm->crt_hash;
struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
return -EINVAL;
ops->init = init;
ops->update = update;
ops->final = final;
ops->digest = digest;
ops->setkey = dalg->dia_setkey ? setkey : nosetkey;
ops->digestsize = dalg->dia_digestsize;
return 0;
}
void crypto_exit_digest_ops(struct crypto_tfm *tfm)
{
}