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_unaligned(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  24 {
  25         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  26         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  27         int ret;
  28         u8 *buffer, *alignbuffer;
  29         unsigned long absize;
  30
  31         absize = keylen + alignmask;
  32         buffer = kmalloc(absize, GFP_ATOMIC);
  33         if (!buffer)
  34                 return -ENOMEM;
  35
  36         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  37         memcpy(alignbuffer, key, keylen);
  38         ret = cia->cia_setkey(tfm, alignbuffer, keylen);
  39         memset(alignbuffer, 0, keylen);
  40         kfree(buffer);
  41         return ret;
  42
  43 }
  44
  45 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  46 {
  47         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  48         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  49
  50         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  51         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
  52                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  53                 return -EINVAL;
  54         }
  55
  56         if ((unsigned long)key & alignmask)
  57                 return setkey_unaligned(tfm, key, keylen);
  58
  59         return cia->cia_setkey(tfm, key, keylen);
  60 }
  61
  62 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
  63                                               const u8 *),
  64                                    struct crypto_tfm *tfm,
  65                                    u8 *dst, const u8 *src)
  66 {
  67         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  68         unsigned int size = crypto_tfm_alg_blocksize(tfm);
  69         u8 buffer[size + alignmask];
  70         u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  71
  72         memcpy(tmp, src, size);
  73         fn(tfm, tmp, tmp);
  74         memcpy(dst, tmp, size);
  75 }
  76
  77 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
  78                                      u8 *dst, const u8 *src)
  79 {
  80         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  81         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  82
  83         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  84                 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
  85                 return;
  86         }
  87
  88         cipher->cia_encrypt(tfm, dst, src);
  89 }
  90
  91 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
  92                                      u8 *dst, const u8 *src)
  93 {
  94         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  95         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  96
  97         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  98                 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
  99                 return;
 100         }
 101
 102         cipher->cia_decrypt(tfm, dst, src);
 103 }
 104
 105 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 106 {
 107         struct cipher_tfm *ops = &tfm->crt_cipher;
 108         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
 109
 110         ops->cit_setkey = setkey;
 111         ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 112                 cipher_encrypt_unaligned : cipher->cia_encrypt;
 113         ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 114                 cipher_decrypt_unaligned : cipher->cia_decrypt;
 115
 116         return 0;
 117 }
 118
 119 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 120 {
 121 }