LXR linux/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
  24static 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
  47static 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
  64static 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
  79static 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
  93static 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
 107int 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}
 120