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hash.c

/*
 * Cryptographic Hash operations.
 * 
 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.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/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>

#include "internal.h"

static unsigned int crypto_hash_ctxsize(struct crypto_alg *alg, u32 type,
                              u32 mask)
{
      return alg->cra_ctxsize;
}

static int hash_setkey_unaligned(struct crypto_hash *crt, const u8 *key,
                             unsigned int keylen)
{
      struct crypto_tfm *tfm = crypto_hash_tfm(crt);
      struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
      unsigned long alignmask = crypto_hash_alignmask(crt);
      int ret;
      u8 *buffer, *alignbuffer;
      unsigned long absize;

      absize = keylen + alignmask;
      buffer = kmalloc(absize, GFP_ATOMIC);
      if (!buffer)
            return -ENOMEM;

      alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
      memcpy(alignbuffer, key, keylen);
      ret = alg->setkey(crt, alignbuffer, keylen);
      memset(alignbuffer, 0, keylen);
      kfree(buffer);
      return ret;
}

static int hash_setkey(struct crypto_hash *crt, const u8 *key,
                   unsigned int keylen)
{
      struct crypto_tfm *tfm = crypto_hash_tfm(crt);
      struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
      unsigned long alignmask = crypto_hash_alignmask(crt);

      if ((unsigned long)key & alignmask)
            return hash_setkey_unaligned(crt, key, keylen);

      return alg->setkey(crt, key, keylen);
}

static int crypto_init_hash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
{
      struct hash_tfm *crt = &tfm->crt_hash;
      struct hash_alg *alg = &tfm->__crt_alg->cra_hash;

      if (alg->digestsize > crypto_tfm_alg_blocksize(tfm))
            return -EINVAL;

      crt->init = alg->init;
      crt->update = alg->update;
      crt->final = alg->final;
      crt->digest = alg->digest;
      crt->setkey = hash_setkey;
      crt->digestsize = alg->digestsize;

      return 0;
}

static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
      __attribute__ ((unused));
static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
{
      seq_printf(m, "type         : hash\n");
      seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
      seq_printf(m, "digestsize   : %u\n", alg->cra_hash.digestsize);
}

const struct crypto_type crypto_hash_type = {
      .ctxsize = crypto_hash_ctxsize,
      .init = crypto_init_hash_ops,
#ifdef CONFIG_PROC_FS
      .show = crypto_hash_show,
#endif
};
EXPORT_SYMBOL_GPL(crypto_hash_type);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Generic cryptographic hash type");

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