crypto/ivgen-plain.c

   1 /*
   2  * QEMU Crypto block IV generator - plain
   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-plain.h"
  24
  25 static int qcrypto_ivgen_plain_init(QCryptoIVGen *ivgen,
  26                                     const uint8_t *key, size_t nkey,
  27                                     Error **errp)
  28 {
  29     return 0;
  30 }
  31
  32 static int qcrypto_ivgen_plain_calculate(QCryptoIVGen *ivgen,
  33                                          uint64_t sector,
  34                                          uint8_t *iv, size_t niv,
  35                                          Error **errp)
  36 {
  37     size_t ivprefix;
  38     uint32_t shortsector = cpu_to_le32((sector & 0xffffffff));
  39     ivprefix = sizeof(shortsector);
  40     if (ivprefix > niv) {
  41         ivprefix = niv;
  42     }
  43     memcpy(iv, &shortsector, ivprefix);
  44     if (ivprefix < niv) {
  45         memset(iv + ivprefix, 0, niv - ivprefix);
  46     }
  47     return 0;
  48 }
  49
  50 static void qcrypto_ivgen_plain_cleanup(QCryptoIVGen *ivgen)
  51 {
  52 }
  53
  54
  55 struct QCryptoIVGenDriver qcrypto_ivgen_plain = {
  56     .init = qcrypto_ivgen_plain_init,
  57     .calculate = qcrypto_ivgen_plain_calculate,
  58     .cleanup = qcrypto_ivgen_plain_cleanup,
  59 };
  60