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