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 <crypto/algapi.h>
  17 #include <linux/kernel.h>
  18 #include <linux/crypto.h>
  19 #include <linux/errno.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include "internal.h"
  23
  24 static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
  25                             unsigned int keylen)
  26 {
  27         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  28         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  29         int ret;
  30         u8 *buffer, *alignbuffer;
  31         unsigned long absize;
  32
  33         absize = keylen + alignmask;
  34         buffer = kmalloc(absize, GFP_ATOMIC);
  35         if (!buffer)
  36                 return -ENOMEM;
  37
  38         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  39         memcpy(alignbuffer, key, keylen);
  40         ret = cia->cia_setkey(tfm, alignbuffer, keylen);
  41         memset(alignbuffer, 0, keylen);
  42         kfree(buffer);
  43         return ret;
  44
  45 }
  46
  47 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  48 {
  49         struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  50         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  51
  52         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  53         if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
  54                 tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  55                 return -EINVAL;
  56         }
  57
  58         if ((unsigned long)key & alignmask)
  59                 return setkey_unaligned(tfm, key, keylen);
  60
  61         return cia->cia_setkey(tfm, key, keylen);
  62 }
  63
  64 static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
  65                                               const u8 *),
  66                                    struct crypto_tfm *tfm,
  67                                    u8 *dst, const u8 *src)
  68 {
  69         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  70         unsigned int size = crypto_tfm_alg_blocksize(tfm);
  71         u8 buffer[MAX_CIPHER_BLOCKSIZE + MAX_CIPHER_ALIGNMASK];
  72         u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  73
  74         memcpy(tmp, src, size);
  75         fn(tfm, tmp, tmp);
  76         memcpy(dst, tmp, size);
  77 }
  78
  79 static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
  80                                      u8 *dst, const u8 *src)
  81 {
  82         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  83         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  84
  85         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  86                 cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
  87                 return;
  88         }
  89
  90         cipher->cia_encrypt(tfm, dst, src);
  91 }
  92
  93 static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
  94                                      u8 *dst, const u8 *src)
  95 {
  96         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  97         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  98
  99         if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
 100                 cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
 101                 return;
 102         }
 103
 104         cipher->cia_decrypt(tfm, dst, src);
 105 }
 106
 107 int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 108 {
 109         struct cipher_tfm *ops = &tfm->crt_cipher;
 110         struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
 111
 112         ops->cit_setkey = setkey;
 113         ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 114                 cipher_encrypt_unaligned : cipher->cia_encrypt;
 115         ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 116                 cipher_decrypt_unaligned : cipher->cia_decrypt;
 117
 118         return 0;
 119 }