crypto/cipher.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * Cipher operations.
   5  *
   6  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   7  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/crypto.h>
  18 #include <linux/errno.h>
  19 #include <linux/scatterlist.h>
  20 #include <linux/string.h>
  21 #include "internal.h"
  22
  23 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  24 {
  25         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  26
  27         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  28         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
  29                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  30                 return -EINVAL;
  31         } else
  32                 return cia->cia_setkey(tfm, key, keylen);
  33 }
  34
  35 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
  36                                               const u8 *),
  37                                    struct crypto_tfm *tfm,
  38                                    u8 *dst, const u8 *src)
  39 {
  40         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  41         unsigned int size = crypto_tfm_alg_blocksize(tfm);
  42         u8 buffer[size + alignmask];
  43         u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  44
  45         memcpy(tmp, src, size);
  46         fn(tfm, tmp, tmp);
  47         memcpy(dst, tmp, size);
  48 }
  49
  50 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
  51                                      u8 *dst, const u8 *src)
  52 {
  53         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  54         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  55
  56         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  57                 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
  58                 return;
  59         }
  60
  61         cipher->cia_encrypt(tfm, dst, src);
  62 }
  63
  64 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
  65                                      u8 *dst, const u8 *src)
  66 {
  67         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  68         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  69
  70         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  71                 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
  72                 return;
  73         }
  74
  75         cipher->cia_decrypt(tfm, dst, src);
  76 }
  77
  78 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
  79 {
  80         struct cipher_tfm *ops = &tfm->crt_cipher;
  81         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  82
  83         ops->cit_setkey = setkey;
  84         ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
  85                 cipher_encrypt_unaligned : cipher->cia_encrypt;
  86         ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
  87                 cipher_decrypt_unaligned : cipher->cia_decrypt;
  88
  89         return 0;
  90 }
  91
  92 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
  93 {
  94 }