cachepc-qemu

Fork of AMDESE/qemu with changes for cachepc side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-qemu
Log | Files | Refs | Submodules | LICENSE | sfeed.txt

ivgen-essiv.c (3571B)

      1/*
      2 * QEMU Crypto block IV generator - essiv
      3 *
      4 * Copyright (c) 2015-2016 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 2.1 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 "qemu/bswap.h"
     23#include "ivgen-essiv.h"
     24
     25typedef struct QCryptoIVGenESSIV QCryptoIVGenESSIV;
     26struct QCryptoIVGenESSIV {
     27    QCryptoCipher *cipher;
     28};
     29
     30static int qcrypto_ivgen_essiv_init(QCryptoIVGen *ivgen,
     31                                    const uint8_t *key, size_t nkey,
     32                                    Error **errp)
     33{
     34    uint8_t *salt;
     35    size_t nhash;
     36    size_t nsalt;
     37    QCryptoIVGenESSIV *essiv = g_new0(QCryptoIVGenESSIV, 1);
     38
     39    /* Not necessarily the same as nkey */
     40    nsalt = qcrypto_cipher_get_key_len(ivgen->cipher);
     41
     42    nhash = qcrypto_hash_digest_len(ivgen->hash);
     43    /* Salt must be larger of hash size or key size */
     44    salt = g_new0(uint8_t, MAX(nhash, nsalt));
     45
     46    if (qcrypto_hash_bytes(ivgen->hash, (const gchar *)key, nkey,
     47                           &salt, &nhash,
     48                           errp) < 0) {
     49        g_free(essiv);
     50        g_free(salt);
     51        return -1;
     52    }
     53
     54    /* Now potentially truncate salt to match cipher key len */
     55    essiv->cipher = qcrypto_cipher_new(ivgen->cipher,
     56                                       QCRYPTO_CIPHER_MODE_ECB,
     57                                       salt, MIN(nhash, nsalt),
     58                                       errp);
     59    if (!essiv->cipher) {
     60        g_free(essiv);
     61        g_free(salt);
     62        return -1;
     63    }
     64
     65    g_free(salt);
     66    ivgen->private = essiv;
     67
     68    return 0;
     69}
     70
     71static int qcrypto_ivgen_essiv_calculate(QCryptoIVGen *ivgen,
     72                                         uint64_t sector,
     73                                         uint8_t *iv, size_t niv,
     74                                         Error **errp)
     75{
     76    QCryptoIVGenESSIV *essiv = ivgen->private;
     77    size_t ndata = qcrypto_cipher_get_block_len(ivgen->cipher);
     78    uint8_t *data = g_new(uint8_t, ndata);
     79
     80    sector = cpu_to_le64(sector);
     81    memcpy(data, (uint8_t *)&sector, MIN(sizeof(sector), ndata));
     82    if (sizeof(sector) < ndata) {
     83        memset(data + sizeof(sector), 0, ndata - sizeof(sector));
     84    }
     85
     86    if (qcrypto_cipher_encrypt(essiv->cipher,
     87                               data,
     88                               data,
     89                               ndata,
     90                               errp) < 0) {
     91        g_free(data);
     92        return -1;
     93    }
     94
     95    if (ndata > niv) {
     96        ndata = niv;
     97    }
     98    memcpy(iv, data, ndata);
     99    if (ndata < niv) {
    100        memset(iv + ndata, 0, niv - ndata);
    101    }
    102    g_free(data);
    103    return 0;
    104}
    105
    106static void qcrypto_ivgen_essiv_cleanup(QCryptoIVGen *ivgen)
    107{
    108    QCryptoIVGenESSIV *essiv = ivgen->private;
    109
    110    qcrypto_cipher_free(essiv->cipher);
    111    g_free(essiv);
    112}
    113
    114
    115struct QCryptoIVGenDriver qcrypto_ivgen_essiv = {
    116    .init = qcrypto_ivgen_essiv_init,
    117    .calculate = qcrypto_ivgen_essiv_calculate,
    118    .cleanup = qcrypto_ivgen_essiv_cleanup,
    119};
    120