qemu/crypto/block.c
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   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
  27static 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
  33bool 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
  50QCryptoBlock *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
  80QCryptoBlock *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
 110QCryptoBlockInfo *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
 127int 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
 137int 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
 147QCryptoCipher *qcrypto_block_get_cipher(QCryptoBlock *block)
 148{
 149    return block->cipher;
 150}
 151
 152
 153QCryptoIVGen *qcrypto_block_get_ivgen(QCryptoBlock *block)
 154{
 155    return block->ivgen;
 156}
 157
 158
 159QCryptoHashAlgorithm qcrypto_block_get_kdf_hash(QCryptoBlock *block)
 160{
 161    return block->kdfhash;
 162}
 163
 164
 165uint64_t qcrypto_block_get_payload_offset(QCryptoBlock *block)
 166{
 167    return block->payload_offset;
 168}
 169
 170
 171void 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
 185int 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
 234int 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}
 281