linux/crypto/cipher.c
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   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/slab.h>
  20#include <linux/string.h>
  21#include "internal.h"
  22
  23static int setkey_unaligned(struct crypto_tfm *tfm, const u8 *key,
  24                            unsigned int keylen)
  25{
  26        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  27        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  28        int ret;
  29        u8 *buffer, *alignbuffer;
  30        unsigned long absize;
  31
  32        absize = keylen + alignmask;
  33        buffer = kmalloc(absize, GFP_ATOMIC);
  34        if (!buffer)
  35                return -ENOMEM;
  36
  37        alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  38        memcpy(alignbuffer, key, keylen);
  39        ret = cia->cia_setkey(tfm, alignbuffer, keylen);
  40        memset(alignbuffer, 0, keylen);
  41        kfree(buffer);
  42        return ret;
  43
  44}
  45
  46static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  47{
  48        struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
  49        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  50
  51        tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  52        if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
  53                tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  54                return -EINVAL;
  55        }
  56
  57        if ((unsigned long)key & alignmask)
  58                return setkey_unaligned(tfm, key, keylen);
  59
  60        return cia->cia_setkey(tfm, key, keylen);
  61}
  62
  63static void cipher_crypt_unaligned(void (*fn)(struct crypto_tfm *, u8 *,
  64                                              const u8 *),
  65                                   struct crypto_tfm *tfm,
  66                                   u8 *dst, const u8 *src)
  67{
  68        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  69        unsigned int size = crypto_tfm_alg_blocksize(tfm);
  70        u8 buffer[size + alignmask];
  71        u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  72
  73        memcpy(tmp, src, size);
  74        fn(tfm, tmp, tmp);
  75        memcpy(dst, tmp, size);
  76}
  77
  78static void cipher_encrypt_unaligned(struct crypto_tfm *tfm,
  79                                     u8 *dst, const u8 *src)
  80{
  81        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  82        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  83
  84        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  85                cipher_crypt_unaligned(cipher->cia_encrypt, tfm, dst, src);
  86                return;
  87        }
  88
  89        cipher->cia_encrypt(tfm, dst, src);
  90}
  91
  92static void cipher_decrypt_unaligned(struct crypto_tfm *tfm,
  93                                     u8 *dst, const u8 *src)
  94{
  95        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  96        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
  97
  98        if (unlikely(((unsigned long)dst | (unsigned long)src) & alignmask)) {
  99                cipher_crypt_unaligned(cipher->cia_decrypt, tfm, dst, src);
 100                return;
 101        }
 102
 103        cipher->cia_decrypt(tfm, dst, src);
 104}
 105
 106int crypto_init_cipher_ops(struct crypto_tfm *tfm)
 107{
 108        struct cipher_tfm *ops = &tfm->crt_cipher;
 109        struct cipher_alg *cipher = &tfm->__crt_alg->cra_cipher;
 110
 111        ops->cit_setkey = setkey;
 112        ops->cit_encrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 113                cipher_encrypt_unaligned : cipher->cia_encrypt;
 114        ops->cit_decrypt_one = crypto_tfm_alg_alignmask(tfm) ?
 115                cipher_decrypt_unaligned : cipher->cia_decrypt;
 116
 117        return 0;
 118}
 119
 120void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 121{
 122}
 123
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