crypto/block.c

   1 /*
   2  * QEMU Crypto block device encryption
   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 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 "blockpriv.h"
  24 #include "block-qcow.h"
  25 #include "block-luks.h"
  26
  27 static const QCryptoBlockDriver *qcrypto_block_drivers[] = {
  28     [Q_CRYPTO_BLOCK_FORMAT_QCOW] = &qcrypto_block_driver_qcow,
  29     [Q_CRYPTO_BLOCK_FORMAT_LUKS] = &qcrypto_block_driver_luks,
  30 };
  31
  32
  33 bool qcrypto_block_has_format(QCryptoBlockFormat format,
  34                               const uint8_t *buf,
  35                               size_t len)
  36 {
  37     const QCryptoBlockDriver *driver;
  38
  39     if (format >= G_N_ELEMENTS(qcrypto_block_drivers) ||
  40         !qcrypto_block_drivers[format]) {
  41         return false;
  42     }
  43
  44     driver = qcrypto_block_drivers[format];
  45
  46     return driver->has_format(buf, len);
  47 }
  48
  49
  50 QCryptoBlock *qcrypto_block_open(QCryptoBlockOpenOptions *options,
  51                                  const char *optprefix,
  52                                  QCryptoBlockReadFunc readfunc,
  53                                  void *opaque,
  54                                  unsigned int flags,
  55                                  Error **errp)
  56 {
  57     QCryptoBlock *block = g_new0(QCryptoBlock, 1);
  58
  59     block->format = options->format;
  60
  61     if (options->format >= G_N_ELEMENTS(qcrypto_block_drivers) ||
  62         !qcrypto_block_drivers[options->format]) {
  63         error_setg(errp, "Unsupported block driver %s",
  64                    QCryptoBlockFormat_str(options->format));
  65         g_free(block);
  66         return NULL;
  67     }
  68
  69     block->driver = qcrypto_block_drivers[options->format];
  70
  71     if (block->driver->open(block, options, optprefix,
  72                             readfunc, opaque, flags, errp) < 0) {
  73         g_free(block);
  74         return NULL;
  75     }
  76
  77     return block;
  78 }
  79
  80
  81 QCryptoBlock *qcrypto_block_create(QCryptoBlockCreateOptions *options,
  82                                    const char *optprefix,
  83                                    QCryptoBlockInitFunc initfunc,
  84                                    QCryptoBlockWriteFunc writefunc,
  85                                    void *opaque,
  86                                    Error **errp)
  87 {
  88     QCryptoBlock *block = g_new0(QCryptoBlock, 1);
  89
  90     block->format = options->format;
  91
  92     if (options->format >= G_N_ELEMENTS(qcrypto_block_drivers) ||
  93         !qcrypto_block_drivers[options->format]) {
  94         error_setg(errp, "Unsupported block driver %s",
  95                    QCryptoBlockFormat_str(options->format));
  96         g_free(block);
  97         return NULL;
  98     }
  99
 100     block->driver = qcrypto_block_drivers[options->format];
 101
 102     if (block->driver->create(block, options, optprefix, initfunc,
 103                               writefunc, opaque, errp) < 0) {
 104         g_free(block);
 105         return NULL;
 106     }
 107
 108     return block;
 109 }
 110
 111
 112 QCryptoBlockInfo *qcrypto_block_get_info(QCryptoBlock *block,
 113                                          Error **errp)
 114 {
 115     QCryptoBlockInfo *info = g_new0(QCryptoBlockInfo, 1);
 116
 117     info->format = block->format;
 118
 119     if (block->driver->get_info &&
 120         block->driver->get_info(block, info, errp) < 0) {
 121         g_free(info);
 122         return NULL;
 123     }
 124
 125     return info;
 126 }
 127
 128
 129 int qcrypto_block_decrypt(QCryptoBlock *block,
 130                           uint64_t offset,
 131                           uint8_t *buf,
 132                           size_t len,
 133                           Error **errp)
 134 {
 135     return block->driver->decrypt(block, offset, buf, len, errp);
 136 }
 137
 138
 139 int qcrypto_block_encrypt(QCryptoBlock *block,
 140                           uint64_t offset,
 141                           uint8_t *buf,
 142                           size_t len,
 143                           Error **errp)
 144 {
 145     return block->driver->encrypt(block, offset, buf, len, errp);
 146 }
 147
 148
 149 QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block)
 150 {
 151     return block->cipher;
 152 }
 153
 154
 155 QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block)
 156 {
 157     return block->ivgen;
 158 }
 159
 160
 161 QCryptoHashAlgorithm qcrypto_block_get_kdf_hash(QCryptoBlock *block)
 162 {
 163     return block->kdfhash;
 164 }
 165
 166
 167 uint64_t qcrypto_block_get_payload_offset(QCryptoBlock *block)
 168 {
 169     return block->payload_offset;
 170 }
 171
 172
 173 uint64_t qcrypto_block_get_sector_size(QCryptoBlock *block)
 174 {
 175     return block->sector_size;
 176 }
 177
 178
 179 void qcrypto_block_free(QCryptoBlock *block)
 180 {
 181     if (!block) {
 182         return;
 183     }
 184
 185     block->driver->cleanup(block);
 186
 187     qcrypto_cipher_free(block->cipher);
 188     qcrypto_ivgen_free(block->ivgen);
 189     g_free(block);
 190 }
 191
 192
 193 int qcrypto_block_decrypt_helper(QCryptoCipher *cipher,
 194                                  size_t niv,
 195                                  QCryptoIVGen *ivgen,
 196                                  int sectorsize,
 197                                  uint64_t offset,
 198                                  uint8_t *buf,
 199                                  size_t len,
 200                                  Error **errp)
 201 {
 202     uint8_t *iv;
 203     int ret = -1;
 204     uint64_t startsector = offset / sectorsize;
 205
 206     assert(QEMU_IS_ALIGNED(offset, sectorsize));
 207     assert(QEMU_IS_ALIGNED(len, sectorsize));
 208
 209     iv = niv ? g_new0(uint8_t, niv) : NULL;
 210
 211     while (len > 0) {
 212         size_t nbytes;
 213         if (niv) {
 214             if (qcrypto_ivgen_calculate(ivgen,
 215                                         startsector,
 216                                         iv, niv,
 217                                         errp) < 0) {
 218                 goto cleanup;
 219             }
 220
 221             if (qcrypto_cipher_setiv(cipher,
 222                                      iv, niv,
 223                                      errp) < 0) {
 224                 goto cleanup;
 225             }
 226         }
 227
 228         nbytes = len > sectorsize ? sectorsize : len;
 229         if (qcrypto_cipher_decrypt(cipher, buf, buf,
 230                                    nbytes, errp) < 0) {
 231             goto cleanup;
 232         }
 233
 234         startsector++;
 235         buf += nbytes;
 236         len -= nbytes;
 237     }
 238
 239     ret = 0;
 240  cleanup:
 241     g_free(iv);
 242     return ret;
 243 }
 244
 245
 246 int qcrypto_block_encrypt_helper(QCryptoCipher *cipher,
 247                                  size_t niv,
 248                                  QCryptoIVGen *ivgen,
 249                                  int sectorsize,
 250                                  uint64_t offset,
 251                                  uint8_t *buf,
 252                                  size_t len,
 253                                  Error **errp)
 254 {
 255     uint8_t *iv;
 256     int ret = -1;
 257     uint64_t startsector = offset / sectorsize;
 258
 259     assert(QEMU_IS_ALIGNED(offset, sectorsize));
 260     assert(QEMU_IS_ALIGNED(len, sectorsize));
 261
 262     iv = niv ? g_new0(uint8_t, niv) : NULL;
 263
 264     while (len > 0) {
 265         size_t nbytes;
 266         if (niv) {
 267             if (qcrypto_ivgen_calculate(ivgen,
 268                                         startsector,
 269                                         iv, niv,
 270                                         errp) < 0) {
 271                 goto cleanup;
 272             }
 273
 274             if (qcrypto_cipher_setiv(cipher,
 275                                      iv, niv,
 276                                      errp) < 0) {
 277                 goto cleanup;
 278             }
 279         }
 280
 281         nbytes = len > sectorsize ? sectorsize : len;
 282         if (qcrypto_cipher_encrypt(cipher, buf, buf,
 283                                    nbytes, errp) < 0) {
 284             goto cleanup;
 285         }
 286
 287         startsector++;
 288         buf += nbytes;
 289         len -= nbytes;
 290     }
 291
 292     ret = 0;
 293  cleanup:
 294     g_free(iv);
 295     return ret;
 296 }