block/crypto.c

   1 /*
   2  * QEMU block full disk 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
  23 #include "block/block_int.h"
  24 #include "sysemu/block-backend.h"
  25 #include "crypto/block.h"
  26 #include "qapi/opts-visitor.h"
  27 #include "qapi/qobject-input-visitor.h"
  28 #include "qapi-visit.h"
  29 #include "qapi/error.h"
  30 #include "block/crypto.h"
  31
  32 typedef struct BlockCrypto BlockCrypto;
  33
  34 struct BlockCrypto {
  35     QCryptoBlock *block;
  36 };
  37
  38
  39 static int block_crypto_probe_generic(QCryptoBlockFormat format,
  40                                       const uint8_t *buf,
  41                                       int buf_size,
  42                                       const char *filename)
  43 {
  44     if (qcrypto_block_has_format(format, buf, buf_size)) {
  45         return 100;
  46     } else {
  47         return 0;
  48     }
  49 }
  50
  51
  52 static ssize_t block_crypto_read_func(QCryptoBlock *block,
  53                                       size_t offset,
  54                                       uint8_t *buf,
  55                                       size_t buflen,
  56                                       void *opaque,
  57                                       Error **errp)
  58 {
  59     BlockDriverState *bs = opaque;
  60     ssize_t ret;
  61
  62     ret = bdrv_pread(bs->file, offset, buf, buflen);
  63     if (ret < 0) {
  64         error_setg_errno(errp, -ret, "Could not read encryption header");
  65         return ret;
  66     }
  67     return ret;
  68 }
  69
  70
  71 struct BlockCryptoCreateData {
  72     const char *filename;
  73     QemuOpts *opts;
  74     BlockBackend *blk;
  75     uint64_t size;
  76 };
  77
  78
  79 static ssize_t block_crypto_write_func(QCryptoBlock *block,
  80                                        size_t offset,
  81                                        const uint8_t *buf,
  82                                        size_t buflen,
  83                                        void *opaque,
  84                                        Error **errp)
  85 {
  86     struct BlockCryptoCreateData *data = opaque;
  87     ssize_t ret;
  88
  89     ret = blk_pwrite(data->blk, offset, buf, buflen, 0);
  90     if (ret < 0) {
  91         error_setg_errno(errp, -ret, "Could not write encryption header");
  92         return ret;
  93     }
  94     return ret;
  95 }
  96
  97
  98 static ssize_t block_crypto_init_func(QCryptoBlock *block,
  99                                       size_t headerlen,
 100                                       void *opaque,
 101                                       Error **errp)
 102 {
 103     struct BlockCryptoCreateData *data = opaque;
 104     int ret;
 105
 106     /* User provided size should reflect amount of space made
 107      * available to the guest, so we must take account of that
 108      * which will be used by the crypto header
 109      */
 110     data->size += headerlen;
 111
 112     qemu_opt_set_number(data->opts, BLOCK_OPT_SIZE, data->size, &error_abort);
 113     ret = bdrv_create_file(data->filename, data->opts, errp);
 114     if (ret < 0) {
 115         return -1;
 116     }
 117
 118     data->blk = blk_new_open(data->filename, NULL, NULL,
 119                              BDRV_O_RDWR | BDRV_O_PROTOCOL, errp);
 120     if (!data->blk) {
 121         return -1;
 122     }
 123
 124     return 0;
 125 }
 126
 127
 128 static QemuOptsList block_crypto_runtime_opts_luks = {
 129     .name = "crypto",
 130     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head),
 131     .desc = {
 132         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 133         { /* end of list */ }
 134     },
 135 };
 136
 137
 138 static QemuOptsList block_crypto_create_opts_luks = {
 139     .name = "crypto",
 140     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head),
 141     .desc = {
 142         {
 143             .name = BLOCK_OPT_SIZE,
 144             .type = QEMU_OPT_SIZE,
 145             .help = "Virtual disk size"
 146         },
 147         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 148         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""),
 149         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""),
 150         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""),
 151         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""),
 152         BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""),
 153         BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""),
 154         { /* end of list */ }
 155     },
 156 };
 157
 158
 159 QCryptoBlockOpenOptions *
 160 block_crypto_open_opts_init(QCryptoBlockFormat format,
 161                             QDict *opts,
 162                             Error **errp)
 163 {
 164     Visitor *v;
 165     QCryptoBlockOpenOptions *ret = NULL;
 166     Error *local_err = NULL;
 167
 168     ret = g_new0(QCryptoBlockOpenOptions, 1);
 169     ret->format = format;
 170
 171     v = qobject_input_visitor_new_keyval(QOBJECT(opts));
 172
 173     visit_start_struct(v, NULL, NULL, 0, &local_err);
 174     if (local_err) {
 175         goto out;
 176     }
 177
 178     switch (format) {
 179     case Q_CRYPTO_BLOCK_FORMAT_LUKS:
 180         visit_type_QCryptoBlockOptionsLUKS_members(
 181             v, &ret->u.luks, &local_err);
 182         break;
 183
 184     case Q_CRYPTO_BLOCK_FORMAT_QCOW:
 185         visit_type_QCryptoBlockOptionsQCow_members(
 186             v, &ret->u.qcow, &local_err);
 187         break;
 188
 189     default:
 190         error_setg(&local_err, "Unsupported block format %d", format);
 191         break;
 192     }
 193     if (!local_err) {
 194         visit_check_struct(v, &local_err);
 195     }
 196
 197     visit_end_struct(v, NULL);
 198
 199  out:
 200     if (local_err) {
 201         error_propagate(errp, local_err);
 202         qapi_free_QCryptoBlockOpenOptions(ret);
 203         ret = NULL;
 204     }
 205     visit_free(v);
 206     return ret;
 207 }
 208
 209
 210 QCryptoBlockCreateOptions *
 211 block_crypto_create_opts_init(QCryptoBlockFormat format,
 212                               QDict *opts,
 213                               Error **errp)
 214 {
 215     Visitor *v;
 216     QCryptoBlockCreateOptions *ret = NULL;
 217     Error *local_err = NULL;
 218
 219     ret = g_new0(QCryptoBlockCreateOptions, 1);
 220     ret->format = format;
 221
 222     v = qobject_input_visitor_new_keyval(QOBJECT(opts));
 223
 224     visit_start_struct(v, NULL, NULL, 0, &local_err);
 225     if (local_err) {
 226         goto out;
 227     }
 228
 229     switch (format) {
 230     case Q_CRYPTO_BLOCK_FORMAT_LUKS:
 231         visit_type_QCryptoBlockCreateOptionsLUKS_members(
 232             v, &ret->u.luks, &local_err);
 233         break;
 234
 235     case Q_CRYPTO_BLOCK_FORMAT_QCOW:
 236         visit_type_QCryptoBlockOptionsQCow_members(
 237             v, &ret->u.qcow, &local_err);
 238         break;
 239
 240     default:
 241         error_setg(&local_err, "Unsupported block format %d", format);
 242         break;
 243     }
 244     if (!local_err) {
 245         visit_check_struct(v, &local_err);
 246     }
 247
 248     visit_end_struct(v, NULL);
 249
 250  out:
 251     if (local_err) {
 252         error_propagate(errp, local_err);
 253         qapi_free_QCryptoBlockCreateOptions(ret);
 254         ret = NULL;
 255     }
 256     visit_free(v);
 257     return ret;
 258 }
 259
 260
 261 static int block_crypto_open_generic(QCryptoBlockFormat format,
 262                                      QemuOptsList *opts_spec,
 263                                      BlockDriverState *bs,
 264                                      QDict *options,
 265                                      int flags,
 266                                      Error **errp)
 267 {
 268     BlockCrypto *crypto = bs->opaque;
 269     QemuOpts *opts = NULL;
 270     Error *local_err = NULL;
 271     int ret = -EINVAL;
 272     QCryptoBlockOpenOptions *open_opts = NULL;
 273     unsigned int cflags = 0;
 274     QDict *cryptoopts = NULL;
 275
 276     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 277                                false, errp);
 278     if (!bs->file) {
 279         return -EINVAL;
 280     }
 281
 282     opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort);
 283     qemu_opts_absorb_qdict(opts, options, &local_err);
 284     if (local_err) {
 285         error_propagate(errp, local_err);
 286         goto cleanup;
 287     }
 288
 289     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 290
 291     open_opts = block_crypto_open_opts_init(format, cryptoopts, errp);
 292     if (!open_opts) {
 293         goto cleanup;
 294     }
 295
 296     if (flags & BDRV_O_NO_IO) {
 297         cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 298     }
 299     crypto->block = qcrypto_block_open(open_opts, NULL,
 300                                        block_crypto_read_func,
 301                                        bs,
 302                                        cflags,
 303                                        errp);
 304
 305     if (!crypto->block) {
 306         ret = -EIO;
 307         goto cleanup;
 308     }
 309
 310     bs->encrypted = true;
 311
 312     ret = 0;
 313  cleanup:
 314     QDECREF(cryptoopts);
 315     qapi_free_QCryptoBlockOpenOptions(open_opts);
 316     return ret;
 317 }
 318
 319
 320 static int block_crypto_create_generic(QCryptoBlockFormat format,
 321                                        const char *filename,
 322                                        QemuOpts *opts,
 323                                        Error **errp)
 324 {
 325     int ret = -EINVAL;
 326     QCryptoBlockCreateOptions *create_opts = NULL;
 327     QCryptoBlock *crypto = NULL;
 328     struct BlockCryptoCreateData data = {
 329         .size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 330                          BDRV_SECTOR_SIZE),
 331         .opts = opts,
 332         .filename = filename,
 333     };
 334     QDict *cryptoopts;
 335
 336     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 337
 338     create_opts = block_crypto_create_opts_init(format, cryptoopts, errp);
 339     if (!create_opts) {
 340         return -1;
 341     }
 342
 343     crypto = qcrypto_block_create(create_opts, NULL,
 344                                   block_crypto_init_func,
 345                                   block_crypto_write_func,
 346                                   &data,
 347                                   errp);
 348
 349     if (!crypto) {
 350         ret = -EIO;
 351         goto cleanup;
 352     }
 353
 354     ret = 0;
 355  cleanup:
 356     QDECREF(cryptoopts);
 357     qcrypto_block_free(crypto);
 358     blk_unref(data.blk);
 359     qapi_free_QCryptoBlockCreateOptions(create_opts);
 360     return ret;
 361 }
 362
 363 static int block_crypto_truncate(BlockDriverState *bs, int64_t offset,
 364                                  PreallocMode prealloc, Error **errp)
 365 {
 366     BlockCrypto *crypto = bs->opaque;
 367     size_t payload_offset =
 368         qcrypto_block_get_payload_offset(crypto->block);
 369
 370     offset += payload_offset;
 371
 372     return bdrv_truncate(bs->file, offset, prealloc, errp);
 373 }
 374
 375 static void block_crypto_close(BlockDriverState *bs)
 376 {
 377     BlockCrypto *crypto = bs->opaque;
 378     qcrypto_block_free(crypto->block);
 379 }
 380
 381
 382 #define BLOCK_CRYPTO_MAX_SECTORS 32
 383
 384 static coroutine_fn int
 385 block_crypto_co_readv(BlockDriverState *bs, int64_t sector_num,
 386                       int remaining_sectors, QEMUIOVector *qiov)
 387 {
 388     BlockCrypto *crypto = bs->opaque;
 389     int cur_nr_sectors; /* number of sectors in current iteration */
 390     uint64_t bytes_done = 0;
 391     uint8_t *cipher_data = NULL;
 392     QEMUIOVector hd_qiov;
 393     int ret = 0;
 394     size_t payload_offset =
 395         qcrypto_block_get_payload_offset(crypto->block) / 512;
 396
 397     qemu_iovec_init(&hd_qiov, qiov->niov);
 398
 399     /* Bounce buffer so we have a linear mem region for
 400      * entire sector. XXX optimize so we avoid bounce
 401      * buffer in case that qiov->niov == 1
 402      */
 403     cipher_data =
 404         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_SECTORS * 512,
 405                                               qiov->size));
 406     if (cipher_data == NULL) {
 407         ret = -ENOMEM;
 408         goto cleanup;
 409     }
 410
 411     while (remaining_sectors) {
 412         cur_nr_sectors = remaining_sectors;
 413
 414         if (cur_nr_sectors > BLOCK_CRYPTO_MAX_SECTORS) {
 415             cur_nr_sectors = BLOCK_CRYPTO_MAX_SECTORS;
 416         }
 417
 418         qemu_iovec_reset(&hd_qiov);
 419         qemu_iovec_add(&hd_qiov, cipher_data, cur_nr_sectors * 512);
 420
 421         ret = bdrv_co_readv(bs->file,
 422                             payload_offset + sector_num,
 423                             cur_nr_sectors, &hd_qiov);
 424         if (ret < 0) {
 425             goto cleanup;
 426         }
 427
 428         if (qcrypto_block_decrypt(crypto->block,
 429                                   sector_num,
 430                                   cipher_data, cur_nr_sectors * 512,
 431                                   NULL) < 0) {
 432             ret = -EIO;
 433             goto cleanup;
 434         }
 435
 436         qemu_iovec_from_buf(qiov, bytes_done,
 437                             cipher_data, cur_nr_sectors * 512);
 438
 439         remaining_sectors -= cur_nr_sectors;
 440         sector_num += cur_nr_sectors;
 441         bytes_done += cur_nr_sectors * 512;
 442     }
 443
 444  cleanup:
 445     qemu_iovec_destroy(&hd_qiov);
 446     qemu_vfree(cipher_data);
 447
 448     return ret;
 449 }
 450
 451
 452 static coroutine_fn int
 453 block_crypto_co_writev(BlockDriverState *bs, int64_t sector_num,
 454                        int remaining_sectors, QEMUIOVector *qiov)
 455 {
 456     BlockCrypto *crypto = bs->opaque;
 457     int cur_nr_sectors; /* number of sectors in current iteration */
 458     uint64_t bytes_done = 0;
 459     uint8_t *cipher_data = NULL;
 460     QEMUIOVector hd_qiov;
 461     int ret = 0;
 462     size_t payload_offset =
 463         qcrypto_block_get_payload_offset(crypto->block) / 512;
 464
 465     qemu_iovec_init(&hd_qiov, qiov->niov);
 466
 467     /* Bounce buffer so we have a linear mem region for
 468      * entire sector. XXX optimize so we avoid bounce
 469      * buffer in case that qiov->niov == 1
 470      */
 471     cipher_data =
 472         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_SECTORS * 512,
 473                                               qiov->size));
 474     if (cipher_data == NULL) {
 475         ret = -ENOMEM;
 476         goto cleanup;
 477     }
 478
 479     while (remaining_sectors) {
 480         cur_nr_sectors = remaining_sectors;
 481
 482         if (cur_nr_sectors > BLOCK_CRYPTO_MAX_SECTORS) {
 483             cur_nr_sectors = BLOCK_CRYPTO_MAX_SECTORS;
 484         }
 485
 486         qemu_iovec_to_buf(qiov, bytes_done,
 487                           cipher_data, cur_nr_sectors * 512);
 488
 489         if (qcrypto_block_encrypt(crypto->block,
 490                                   sector_num,
 491                                   cipher_data, cur_nr_sectors * 512,
 492                                   NULL) < 0) {
 493             ret = -EIO;
 494             goto cleanup;
 495         }
 496
 497         qemu_iovec_reset(&hd_qiov);
 498         qemu_iovec_add(&hd_qiov, cipher_data, cur_nr_sectors * 512);
 499
 500         ret = bdrv_co_writev(bs->file,
 501                              payload_offset + sector_num,
 502                              cur_nr_sectors, &hd_qiov);
 503         if (ret < 0) {
 504             goto cleanup;
 505         }
 506
 507         remaining_sectors -= cur_nr_sectors;
 508         sector_num += cur_nr_sectors;
 509         bytes_done += cur_nr_sectors * 512;
 510     }
 511
 512  cleanup:
 513     qemu_iovec_destroy(&hd_qiov);
 514     qemu_vfree(cipher_data);
 515
 516     return ret;
 517 }
 518
 519
 520 static int64_t block_crypto_getlength(BlockDriverState *bs)
 521 {
 522     BlockCrypto *crypto = bs->opaque;
 523     int64_t len = bdrv_getlength(bs->file->bs);
 524
 525     ssize_t offset = qcrypto_block_get_payload_offset(crypto->block);
 526
 527     len -= offset;
 528
 529     return len;
 530 }
 531
 532
 533 static int block_crypto_probe_luks(const uint8_t *buf,
 534                                    int buf_size,
 535                                    const char *filename) {
 536     return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 537                                       buf, buf_size, filename);
 538 }
 539
 540 static int block_crypto_open_luks(BlockDriverState *bs,
 541                                   QDict *options,
 542                                   int flags,
 543                                   Error **errp)
 544 {
 545     return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 546                                      &block_crypto_runtime_opts_luks,
 547                                      bs, options, flags, errp);
 548 }
 549
 550 static int block_crypto_create_luks(const char *filename,
 551                                     QemuOpts *opts,
 552                                     Error **errp)
 553 {
 554     return block_crypto_create_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 555                                        filename, opts, errp);
 556 }
 557
 558 static int block_crypto_get_info_luks(BlockDriverState *bs,
 559                                       BlockDriverInfo *bdi)
 560 {
 561     BlockDriverInfo subbdi;
 562     int ret;
 563
 564     ret = bdrv_get_info(bs->file->bs, &subbdi);
 565     if (ret != 0) {
 566         return ret;
 567     }
 568
 569     bdi->unallocated_blocks_are_zero = false;
 570     bdi->can_write_zeroes_with_unmap = false;
 571     bdi->cluster_size = subbdi.cluster_size;
 572
 573     return 0;
 574 }
 575
 576 static ImageInfoSpecific *
 577 block_crypto_get_specific_info_luks(BlockDriverState *bs)
 578 {
 579     BlockCrypto *crypto = bs->opaque;
 580     ImageInfoSpecific *spec_info;
 581     QCryptoBlockInfo *info;
 582
 583     info = qcrypto_block_get_info(crypto->block, NULL);
 584     if (!info) {
 585         return NULL;
 586     }
 587     if (info->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) {
 588         qapi_free_QCryptoBlockInfo(info);
 589         return NULL;
 590     }
 591
 592     spec_info = g_new(ImageInfoSpecific, 1);
 593     spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
 594     spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
 595     *spec_info->u.luks.data = info->u.luks;
 596
 597     /* Blank out pointers we've just stolen to avoid double free */
 598     memset(&info->u.luks, 0, sizeof(info->u.luks));
 599
 600     qapi_free_QCryptoBlockInfo(info);
 601
 602     return spec_info;
 603 }
 604
 605 BlockDriver bdrv_crypto_luks = {
 606     .format_name        = "luks",
 607     .instance_size      = sizeof(BlockCrypto),
 608     .bdrv_probe         = block_crypto_probe_luks,
 609     .bdrv_open          = block_crypto_open_luks,
 610     .bdrv_close         = block_crypto_close,
 611     .bdrv_child_perm    = bdrv_format_default_perms,
 612     .bdrv_create        = block_crypto_create_luks,
 613     .bdrv_truncate      = block_crypto_truncate,
 614     .create_opts        = &block_crypto_create_opts_luks,
 615
 616     .bdrv_co_readv      = block_crypto_co_readv,
 617     .bdrv_co_writev     = block_crypto_co_writev,
 618     .bdrv_getlength     = block_crypto_getlength,
 619     .bdrv_get_info      = block_crypto_get_info_luks,
 620     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 621 };
 622
 623 static void block_crypto_init(void)
 624 {
 625     bdrv_register(&bdrv_crypto_luks);
 626 }
 627
 628 block_init(block_crypto_init);