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ablkcipher.c

/*
 * Asynchronous block chaining cipher operations.
 * 
 * This is the asynchronous version of blkcipher.c indicating completion
 * via a callback.
 *
 * 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 <crypto/algapi.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/seq_file.h>

static int setkey_unaligned(struct crypto_ablkcipher *tfm, const u8 *key,
                      unsigned int keylen)
{
      struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
      unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);
      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 = cipher->setkey(tfm, alignbuffer, keylen);
      memset(alignbuffer, 0, keylen);
      kfree(buffer);
      return ret;
}

static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
              unsigned int keylen)
{
      struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
      unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);

      if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
            crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
            return -EINVAL;
      }

      if ((unsigned long)key & alignmask)
            return setkey_unaligned(tfm, key, keylen);

      return cipher->setkey(tfm, key, keylen);
}

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

static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
                              u32 mask)
{
      struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
      struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;

      if (alg->ivsize > PAGE_SIZE / 8)
            return -EINVAL;

      crt->setkey = setkey;
      crt->encrypt = alg->encrypt;
      crt->decrypt = alg->decrypt;
      crt->ivsize = alg->ivsize;

      return 0;
}

static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
      __attribute__ ((unused));
static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
{
      struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;

      seq_printf(m, "type         : ablkcipher\n");
      seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
      seq_printf(m, "min keysize  : %u\n", ablkcipher->min_keysize);
      seq_printf(m, "max keysize  : %u\n", ablkcipher->max_keysize);
      seq_printf(m, "ivsize       : %u\n", ablkcipher->ivsize);
}

const struct crypto_type crypto_ablkcipher_type = {
      .ctxsize = crypto_ablkcipher_ctxsize,
      .init = crypto_init_ablkcipher_ops,
#ifdef CONFIG_PROC_FS
      .show = crypto_ablkcipher_show,
#endif
};
EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Asynchronous block chaining cipher type");

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