LXR qemu/crypto/cipher.c

   1/*
   2 * QEMU Crypto cipher algorithms
   3 *
   4 * Copyright (c) 2015 Red Hat, Inc.
   5 *
   6 * This library is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU Lesser General Public
   8 * License as published by the Free Software Foundation; either
   9 * version 2 of the License, or (at your option) any later version.
  10 *
  11 * This library is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * Lesser General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU Lesser General Public
  17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18 *
  19 */
  20
  21#include "qemu/osdep.h"
  22#include "qapi/error.h"
  23#include "crypto/cipher.h"
  24
  25
  26static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
  27    [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  28    [QCRYPTO_CIPHER_ALG_AES_192] = 24,
  29    [QCRYPTO_CIPHER_ALG_AES_256] = 32,
  30    [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  31    [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
  32    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  33    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
  34    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
  35    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  36    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
  37    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
  38};
  39
  40static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
  41    [QCRYPTO_CIPHER_ALG_AES_128] = 16,
  42    [QCRYPTO_CIPHER_ALG_AES_192] = 16,
  43    [QCRYPTO_CIPHER_ALG_AES_256] = 16,
  44    [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
  45    [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
  46    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
  47    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
  48    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
  49    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
  50    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
  51    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
  52};
  53
  54static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
  55    [QCRYPTO_CIPHER_MODE_ECB] = false,
  56    [QCRYPTO_CIPHER_MODE_CBC] = true,
  57    [QCRYPTO_CIPHER_MODE_XTS] = true,
  58};
  59
  60
  61size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg)
  62{
  63    if (alg >= G_N_ELEMENTS(alg_key_len)) {
  64        return 0;
  65    }
  66    return alg_block_len[alg];
  67}
  68
  69
  70size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg)
  71{
  72    if (alg >= G_N_ELEMENTS(alg_key_len)) {
  73        return 0;
  74    }
  75    return alg_key_len[alg];
  76}
  77
  78
  79size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
  80                                 QCryptoCipherMode mode)
  81{
  82    if (alg >= G_N_ELEMENTS(alg_block_len)) {
  83        return 0;
  84    }
  85    if (mode >= G_N_ELEMENTS(mode_need_iv)) {
  86        return 0;
  87    }
  88
  89    if (mode_need_iv[mode]) {
  90        return alg_block_len[alg];
  91    }
  92    return 0;
  93}
  94
  95
  96static bool
  97qcrypto_cipher_validate_key_length(QCryptoCipherAlgorithm alg,
  98                                   QCryptoCipherMode mode,
  99                                   size_t nkey,
 100                                   Error **errp)
 101{
 102    if ((unsigned)alg >= QCRYPTO_CIPHER_ALG__MAX) {
 103        error_setg(errp, "Cipher algorithm %d out of range",
 104                   alg);
 105        return false;
 106    }
 107
 108    if (mode == QCRYPTO_CIPHER_MODE_XTS) {
 109        if (alg == QCRYPTO_CIPHER_ALG_DES_RFB) {
 110            error_setg(errp, "XTS mode not compatible with DES-RFB");
 111            return false;
 112        }
 113        if (nkey % 2) {
 114            error_setg(errp, "XTS cipher key length should be a multiple of 2");
 115            return false;
 116        }
 117
 118        if (alg_key_len[alg] != (nkey / 2)) {
 119            error_setg(errp, "Cipher key length %zu should be %zu",
 120                       nkey, alg_key_len[alg] * 2);
 121            return false;
 122        }
 123    } else {
 124        if (alg_key_len[alg] != nkey) {
 125            error_setg(errp, "Cipher key length %zu should be %zu",
 126                       nkey, alg_key_len[alg]);
 127            return false;
 128        }
 129    }
 130    return true;
 131}
 132
 133#if defined(CONFIG_GCRYPT) || defined(CONFIG_NETTLE)
 134static uint8_t *
 135qcrypto_cipher_munge_des_rfb_key(const uint8_t *key,
 136                                 size_t nkey)
 137{
 138    uint8_t *ret = g_new0(uint8_t, nkey);
 139    size_t i;
 140    for (i = 0; i < nkey; i++) {
 141        uint8_t r = key[i];
 142        r = (r & 0xf0) >> 4 | (r & 0x0f) << 4;
 143        r = (r & 0xcc) >> 2 | (r & 0x33) << 2;
 144        r = (r & 0xaa) >> 1 | (r & 0x55) << 1;
 145        ret[i] = r;
 146    }
 147    return ret;
 148}
 149#endif /* CONFIG_GCRYPT || CONFIG_NETTLE */
 150
 151#ifdef CONFIG_GCRYPT
 152#include "crypto/cipher-gcrypt.c"
 153#elif defined CONFIG_NETTLE
 154#include "crypto/cipher-nettle.c"
 155#else
 156#include "crypto/cipher-builtin.c"
 157#endif
 158