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 "block/qdict.h"
  25 #include "sysemu/block-backend.h"
  26 #include "crypto/block.h"
  27 #include "qapi/opts-visitor.h"
  28 #include "qapi/qapi-visit-crypto.h"
  29 #include "qapi/qobject-input-visitor.h"
  30 #include "qapi/error.h"
  31 #include "qemu/module.h"
  32 #include "qemu/option.h"
  33 #include "qemu/cutils.h"
  34 #include "crypto.h"
  35
  36 typedef struct BlockCrypto BlockCrypto;
  37
  38 struct BlockCrypto {
  39     QCryptoBlock *block;
  40     bool updating_keys;
  41 };
  42
  43
  44 static int block_crypto_probe_generic(QCryptoBlockFormat format,
  45                                       const uint8_t *buf,
  46                                       int buf_size,
  47                                       const char *filename)
  48 {
  49     if (qcrypto_block_has_format(format, buf, buf_size)) {
  50         return 100;
  51     } else {
  52         return 0;
  53     }
  54 }
  55
  56
  57 static ssize_t block_crypto_read_func(QCryptoBlock *block,
  58                                       size_t offset,
  59                                       uint8_t *buf,
  60                                       size_t buflen,
  61                                       void *opaque,
  62                                       Error **errp)
  63 {
  64     BlockDriverState *bs = opaque;
  65     ssize_t ret;
  66
  67     ret = bdrv_pread(bs->file, offset, buf, buflen);
  68     if (ret < 0) {
  69         error_setg_errno(errp, -ret, "Could not read encryption header");
  70         return ret;
  71     }
  72     return ret;
  73 }
  74
  75 static ssize_t block_crypto_write_func(QCryptoBlock *block,
  76                                        size_t offset,
  77                                        const uint8_t *buf,
  78                                        size_t buflen,
  79                                        void *opaque,
  80                                        Error **errp)
  81 {
  82     BlockDriverState *bs = opaque;
  83     ssize_t ret;
  84
  85     ret = bdrv_pwrite(bs->file, offset, buf, buflen);
  86     if (ret < 0) {
  87         error_setg_errno(errp, -ret, "Could not write encryption header");
  88         return ret;
  89     }
  90     return ret;
  91 }
  92
  93
  94 struct BlockCryptoCreateData {
  95     BlockBackend *blk;
  96     uint64_t size;
  97     PreallocMode prealloc;
  98 };
  99
 100
 101 static ssize_t block_crypto_create_write_func(QCryptoBlock *block,
 102                                               size_t offset,
 103                                               const uint8_t *buf,
 104                                               size_t buflen,
 105                                               void *opaque,
 106                                               Error **errp)
 107 {
 108     struct BlockCryptoCreateData *data = opaque;
 109     ssize_t ret;
 110
 111     ret = blk_pwrite(data->blk, offset, buf, buflen, 0);
 112     if (ret < 0) {
 113         error_setg_errno(errp, -ret, "Could not write encryption header");
 114         return ret;
 115     }
 116     return ret;
 117 }
 118
 119 static ssize_t block_crypto_create_init_func(QCryptoBlock *block,
 120                                              size_t headerlen,
 121                                              void *opaque,
 122                                              Error **errp)
 123 {
 124     struct BlockCryptoCreateData *data = opaque;
 125     Error *local_error = NULL;
 126     int ret;
 127
 128     if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) {
 129         ret = -EFBIG;
 130         goto error;
 131     }
 132
 133     /* User provided size should reflect amount of space made
 134      * available to the guest, so we must take account of that
 135      * which will be used by the crypto header
 136      */
 137     ret = blk_truncate(data->blk, data->size + headerlen, false,
 138                        data->prealloc, 0, &local_error);
 139
 140     if (ret >= 0) {
 141         return ret;
 142     }
 143
 144 error:
 145     if (ret == -EFBIG) {
 146         /* Replace the error message with a better one */
 147         error_free(local_error);
 148         error_setg(errp, "The requested file size is too large");
 149     } else {
 150         error_propagate(errp, local_error);
 151     }
 152
 153     return ret;
 154 }
 155
 156
 157 static QemuOptsList block_crypto_runtime_opts_luks = {
 158     .name = "crypto",
 159     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head),
 160     .desc = {
 161         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 162         { /* end of list */ }
 163     },
 164 };
 165
 166
 167 static QemuOptsList block_crypto_create_opts_luks = {
 168     .name = "crypto",
 169     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head),
 170     .desc = {
 171         {
 172             .name = BLOCK_OPT_SIZE,
 173             .type = QEMU_OPT_SIZE,
 174             .help = "Virtual disk size"
 175         },
 176         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 177         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""),
 178         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""),
 179         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""),
 180         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""),
 181         BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""),
 182         BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""),
 183         { /* end of list */ }
 184     },
 185 };
 186
 187
 188 static QemuOptsList block_crypto_amend_opts_luks = {
 189     .name = "crypto",
 190     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head),
 191     .desc = {
 192         BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(""),
 193         BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(""),
 194         BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(""),
 195         BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(""),
 196         BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""),
 197         { /* end of list */ }
 198     },
 199 };
 200
 201 QCryptoBlockOpenOptions *
 202 block_crypto_open_opts_init(QDict *opts, Error **errp)
 203 {
 204     Visitor *v;
 205     QCryptoBlockOpenOptions *ret;
 206
 207     v = qobject_input_visitor_new_flat_confused(opts, errp);
 208     if (!v) {
 209         return NULL;
 210     }
 211
 212     visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp);
 213
 214     visit_free(v);
 215     return ret;
 216 }
 217
 218
 219 QCryptoBlockCreateOptions *
 220 block_crypto_create_opts_init(QDict *opts, Error **errp)
 221 {
 222     Visitor *v;
 223     QCryptoBlockCreateOptions *ret;
 224
 225     v = qobject_input_visitor_new_flat_confused(opts, errp);
 226     if (!v) {
 227         return NULL;
 228     }
 229
 230     visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp);
 231
 232     visit_free(v);
 233     return ret;
 234 }
 235
 236 QCryptoBlockAmendOptions *
 237 block_crypto_amend_opts_init(QDict *opts, Error **errp)
 238 {
 239     Visitor *v;
 240     QCryptoBlockAmendOptions *ret;
 241
 242     v = qobject_input_visitor_new_flat_confused(opts, errp);
 243     if (!v) {
 244         return NULL;
 245     }
 246
 247     visit_type_QCryptoBlockAmendOptions(v, NULL, &ret, errp);
 248
 249     visit_free(v);
 250     return ret;
 251 }
 252
 253
 254 static int block_crypto_open_generic(QCryptoBlockFormat format,
 255                                      QemuOptsList *opts_spec,
 256                                      BlockDriverState *bs,
 257                                      QDict *options,
 258                                      int flags,
 259                                      Error **errp)
 260 {
 261     BlockCrypto *crypto = bs->opaque;
 262     QemuOpts *opts = NULL;
 263     Error *local_err = NULL;
 264     int ret = -EINVAL;
 265     QCryptoBlockOpenOptions *open_opts = NULL;
 266     unsigned int cflags = 0;
 267     QDict *cryptoopts = NULL;
 268
 269     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
 270                                BDRV_CHILD_IMAGE, false, errp);
 271     if (!bs->file) {
 272         return -EINVAL;
 273     }
 274
 275     bs->supported_write_flags = BDRV_REQ_FUA &
 276         bs->file->bs->supported_write_flags;
 277
 278     opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort);
 279     if (!qemu_opts_absorb_qdict(opts, options, &local_err)) {
 280         error_propagate(errp, local_err);
 281         goto cleanup;
 282     }
 283
 284     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 285     qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format));
 286
 287     open_opts = block_crypto_open_opts_init(cryptoopts, errp);
 288     if (!open_opts) {
 289         goto cleanup;
 290     }
 291
 292     if (flags & BDRV_O_NO_IO) {
 293         cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 294     }
 295     crypto->block = qcrypto_block_open(open_opts, NULL,
 296                                        block_crypto_read_func,
 297                                        bs,
 298                                        cflags,
 299                                        1,
 300                                        errp);
 301
 302     if (!crypto->block) {
 303         ret = -EIO;
 304         goto cleanup;
 305     }
 306
 307     bs->encrypted = true;
 308
 309     ret = 0;
 310  cleanup:
 311     qobject_unref(cryptoopts);
 312     qapi_free_QCryptoBlockOpenOptions(open_opts);
 313     return ret;
 314 }
 315
 316
 317 static int block_crypto_co_create_generic(BlockDriverState *bs,
 318                                           int64_t size,
 319                                           QCryptoBlockCreateOptions *opts,
 320                                           PreallocMode prealloc,
 321                                           Error **errp)
 322 {
 323     int ret;
 324     BlockBackend *blk;
 325     QCryptoBlock *crypto = NULL;
 326     struct BlockCryptoCreateData data;
 327
 328     blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
 329                           errp);
 330     if (!blk) {
 331         ret = -EPERM;
 332         goto cleanup;
 333     }
 334
 335     if (prealloc == PREALLOC_MODE_METADATA) {
 336         prealloc = PREALLOC_MODE_OFF;
 337     }
 338
 339     data = (struct BlockCryptoCreateData) {
 340         .blk = blk,
 341         .size = size,
 342         .prealloc = prealloc,
 343     };
 344
 345     crypto = qcrypto_block_create(opts, NULL,
 346                                   block_crypto_create_init_func,
 347                                   block_crypto_create_write_func,
 348                                   &data,
 349                                   errp);
 350
 351     if (!crypto) {
 352         ret = -EIO;
 353         goto cleanup;
 354     }
 355
 356     ret = 0;
 357  cleanup:
 358     qcrypto_block_free(crypto);
 359     blk_unref(blk);
 360     return ret;
 361 }
 362
 363 static int coroutine_fn
 364 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 365                          PreallocMode prealloc, BdrvRequestFlags flags,
 366                          Error **errp)
 367 {
 368     BlockCrypto *crypto = bs->opaque;
 369     uint64_t payload_offset =
 370         qcrypto_block_get_payload_offset(crypto->block);
 371
 372     if (payload_offset > INT64_MAX - offset) {
 373         error_setg(errp, "The requested file size is too large");
 374         return -EFBIG;
 375     }
 376
 377     offset += payload_offset;
 378
 379     return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp);
 380 }
 381
 382 static void block_crypto_close(BlockDriverState *bs)
 383 {
 384     BlockCrypto *crypto = bs->opaque;
 385     qcrypto_block_free(crypto->block);
 386 }
 387
 388 static int block_crypto_reopen_prepare(BDRVReopenState *state,
 389                                        BlockReopenQueue *queue, Error **errp)
 390 {
 391     /* nothing needs checking */
 392     return 0;
 393 }
 394
 395 /*
 396  * 1 MB bounce buffer gives good performance / memory tradeoff
 397  * when using cache=none|directsync.
 398  */
 399 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024)
 400
 401 static coroutine_fn int
 402 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 403                        QEMUIOVector *qiov, int flags)
 404 {
 405     BlockCrypto *crypto = bs->opaque;
 406     uint64_t cur_bytes; /* number of bytes in current iteration */
 407     uint64_t bytes_done = 0;
 408     uint8_t *cipher_data = NULL;
 409     QEMUIOVector hd_qiov;
 410     int ret = 0;
 411     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 412     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 413
 414     assert(!flags);
 415     assert(payload_offset < INT64_MAX);
 416     assert(QEMU_IS_ALIGNED(offset, sector_size));
 417     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 418
 419     qemu_iovec_init(&hd_qiov, qiov->niov);
 420
 421     /* Bounce buffer because we don't wish to expose cipher text
 422      * in qiov which points to guest memory.
 423      */
 424     cipher_data =
 425         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 426                                               qiov->size));
 427     if (cipher_data == NULL) {
 428         ret = -ENOMEM;
 429         goto cleanup;
 430     }
 431
 432     while (bytes) {
 433         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 434
 435         qemu_iovec_reset(&hd_qiov);
 436         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 437
 438         ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done,
 439                              cur_bytes, &hd_qiov, 0);
 440         if (ret < 0) {
 441             goto cleanup;
 442         }
 443
 444         if (qcrypto_block_decrypt(crypto->block, offset + bytes_done,
 445                                   cipher_data, cur_bytes, NULL) < 0) {
 446             ret = -EIO;
 447             goto cleanup;
 448         }
 449
 450         qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes);
 451
 452         bytes -= cur_bytes;
 453         bytes_done += cur_bytes;
 454     }
 455
 456  cleanup:
 457     qemu_iovec_destroy(&hd_qiov);
 458     qemu_vfree(cipher_data);
 459
 460     return ret;
 461 }
 462
 463
 464 static coroutine_fn int
 465 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 466                         QEMUIOVector *qiov, int flags)
 467 {
 468     BlockCrypto *crypto = bs->opaque;
 469     uint64_t cur_bytes; /* number of bytes in current iteration */
 470     uint64_t bytes_done = 0;
 471     uint8_t *cipher_data = NULL;
 472     QEMUIOVector hd_qiov;
 473     int ret = 0;
 474     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 475     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 476
 477     assert(!(flags & ~BDRV_REQ_FUA));
 478     assert(payload_offset < INT64_MAX);
 479     assert(QEMU_IS_ALIGNED(offset, sector_size));
 480     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 481
 482     qemu_iovec_init(&hd_qiov, qiov->niov);
 483
 484     /* Bounce buffer because we're not permitted to touch
 485      * contents of qiov - it points to guest memory.
 486      */
 487     cipher_data =
 488         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 489                                               qiov->size));
 490     if (cipher_data == NULL) {
 491         ret = -ENOMEM;
 492         goto cleanup;
 493     }
 494
 495     while (bytes) {
 496         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 497
 498         qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes);
 499
 500         if (qcrypto_block_encrypt(crypto->block, offset + bytes_done,
 501                                   cipher_data, cur_bytes, NULL) < 0) {
 502             ret = -EIO;
 503             goto cleanup;
 504         }
 505
 506         qemu_iovec_reset(&hd_qiov);
 507         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 508
 509         ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done,
 510                               cur_bytes, &hd_qiov, flags);
 511         if (ret < 0) {
 512             goto cleanup;
 513         }
 514
 515         bytes -= cur_bytes;
 516         bytes_done += cur_bytes;
 517     }
 518
 519  cleanup:
 520     qemu_iovec_destroy(&hd_qiov);
 521     qemu_vfree(cipher_data);
 522
 523     return ret;
 524 }
 525
 526 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp)
 527 {
 528     BlockCrypto *crypto = bs->opaque;
 529     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 530     bs->bl.request_alignment = sector_size; /* No sub-sector I/O */
 531 }
 532
 533
 534 static int64_t block_crypto_getlength(BlockDriverState *bs)
 535 {
 536     BlockCrypto *crypto = bs->opaque;
 537     int64_t len = bdrv_getlength(bs->file->bs);
 538
 539     uint64_t offset = qcrypto_block_get_payload_offset(crypto->block);
 540     assert(offset < INT64_MAX);
 541
 542     if (offset > len) {
 543         return -EIO;
 544     }
 545
 546     len -= offset;
 547
 548     return len;
 549 }
 550
 551
 552 static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts,
 553                                               BlockDriverState *in_bs,
 554                                               Error **errp)
 555 {
 556     g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
 557     Error *local_err = NULL;
 558     BlockMeasureInfo *info;
 559     uint64_t size;
 560     size_t luks_payload_size;
 561     QDict *cryptoopts;
 562
 563     /*
 564      * Preallocation mode doesn't affect size requirements but we must consume
 565      * the option.
 566      */
 567     g_free(qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC));
 568
 569     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 570
 571     if (in_bs) {
 572         int64_t ssize = bdrv_getlength(in_bs);
 573
 574         if (ssize < 0) {
 575             error_setg_errno(&local_err, -ssize,
 576                              "Unable to get image virtual_size");
 577             goto err;
 578         }
 579
 580         size = ssize;
 581     }
 582
 583     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 584             &block_crypto_create_opts_luks, true);
 585     qdict_put_str(cryptoopts, "format", "luks");
 586     create_opts = block_crypto_create_opts_init(cryptoopts, &local_err);
 587     qobject_unref(cryptoopts);
 588     if (!create_opts) {
 589         goto err;
 590     }
 591
 592     if (!qcrypto_block_calculate_payload_offset(create_opts, NULL,
 593                                                 &luks_payload_size,
 594                                                 &local_err)) {
 595         goto err;
 596     }
 597
 598     /*
 599      * Unallocated blocks are still encrypted so allocation status makes no
 600      * difference to the file size.
 601      */
 602     info = g_new0(BlockMeasureInfo, 1);
 603     info->fully_allocated = luks_payload_size + size;
 604     info->required = luks_payload_size + size;
 605     return info;
 606
 607 err:
 608     error_propagate(errp, local_err);
 609     return NULL;
 610 }
 611
 612
 613 static int block_crypto_probe_luks(const uint8_t *buf,
 614                                    int buf_size,
 615                                    const char *filename) {
 616     return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 617                                       buf, buf_size, filename);
 618 }
 619
 620 static int block_crypto_open_luks(BlockDriverState *bs,
 621                                   QDict *options,
 622                                   int flags,
 623                                   Error **errp)
 624 {
 625     return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 626                                      &block_crypto_runtime_opts_luks,
 627                                      bs, options, flags, errp);
 628 }
 629
 630 static int coroutine_fn
 631 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
 632 {
 633     BlockdevCreateOptionsLUKS *luks_opts;
 634     BlockDriverState *bs = NULL;
 635     QCryptoBlockCreateOptions create_opts;
 636     PreallocMode preallocation = PREALLOC_MODE_OFF;
 637     int ret;
 638
 639     assert(create_options->driver == BLOCKDEV_DRIVER_LUKS);
 640     luks_opts = &create_options->u.luks;
 641
 642     bs = bdrv_open_blockdev_ref(luks_opts->file, errp);
 643     if (bs == NULL) {
 644         return -EIO;
 645     }
 646
 647     create_opts = (QCryptoBlockCreateOptions) {
 648         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 649         .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts),
 650     };
 651
 652     if (luks_opts->has_preallocation) {
 653         preallocation = luks_opts->preallocation;
 654     }
 655
 656     ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
 657                                          preallocation, errp);
 658     if (ret < 0) {
 659         goto fail;
 660     }
 661
 662     ret = 0;
 663 fail:
 664     bdrv_unref(bs);
 665     return ret;
 666 }
 667
 668 static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv,
 669                                                          const char *filename,
 670                                                          QemuOpts *opts,
 671                                                          Error **errp)
 672 {
 673     QCryptoBlockCreateOptions *create_opts = NULL;
 674     BlockDriverState *bs = NULL;
 675     QDict *cryptoopts;
 676     PreallocMode prealloc;
 677     char *buf = NULL;
 678     int64_t size;
 679     int ret;
 680     Error *local_err = NULL;
 681
 682     /* Parse options */
 683     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 684
 685     buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
 686     prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
 687                                PREALLOC_MODE_OFF, &local_err);
 688     g_free(buf);
 689     if (local_err) {
 690         error_propagate(errp, local_err);
 691         return -EINVAL;
 692     }
 693
 694     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 695                                              &block_crypto_create_opts_luks,
 696                                              true);
 697
 698     qdict_put_str(cryptoopts, "format", "luks");
 699     create_opts = block_crypto_create_opts_init(cryptoopts, errp);
 700     if (!create_opts) {
 701         ret = -EINVAL;
 702         goto fail;
 703     }
 704
 705     /* Create protocol layer */
 706     ret = bdrv_create_file(filename, opts, errp);
 707     if (ret < 0) {
 708         goto fail;
 709     }
 710
 711     bs = bdrv_open(filename, NULL, NULL,
 712                    BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 713     if (!bs) {
 714         ret = -EINVAL;
 715         goto fail;
 716     }
 717
 718     /* Create format layer */
 719     ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp);
 720     if (ret < 0) {
 721         goto fail;
 722     }
 723
 724     ret = 0;
 725 fail:
 726     /*
 727      * If an error occurred, delete 'filename'. Even if the file existed
 728      * beforehand, it has been truncated and corrupted in the process.
 729      */
 730     if (ret && bs) {
 731         Error *local_delete_err = NULL;
 732         int r_del = bdrv_co_delete_file(bs, &local_delete_err);
 733         /*
 734          * ENOTSUP will happen if the block driver doesn't support
 735          * the 'bdrv_co_delete_file' interface. This is a predictable
 736          * scenario and shouldn't be reported back to the user.
 737          */
 738         if ((r_del < 0) && (r_del != -ENOTSUP)) {
 739             error_report_err(local_delete_err);
 740         }
 741     }
 742
 743     bdrv_unref(bs);
 744     qapi_free_QCryptoBlockCreateOptions(create_opts);
 745     qobject_unref(cryptoopts);
 746     return ret;
 747 }
 748
 749 static int block_crypto_get_info_luks(BlockDriverState *bs,
 750                                       BlockDriverInfo *bdi)
 751 {
 752     BlockDriverInfo subbdi;
 753     int ret;
 754
 755     ret = bdrv_get_info(bs->file->bs, &subbdi);
 756     if (ret != 0) {
 757         return ret;
 758     }
 759
 760     bdi->cluster_size = subbdi.cluster_size;
 761
 762     return 0;
 763 }
 764
 765 static ImageInfoSpecific *
 766 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp)
 767 {
 768     BlockCrypto *crypto = bs->opaque;
 769     ImageInfoSpecific *spec_info;
 770     QCryptoBlockInfo *info;
 771
 772     info = qcrypto_block_get_info(crypto->block, errp);
 773     if (!info) {
 774         return NULL;
 775     }
 776     assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS);
 777
 778     spec_info = g_new(ImageInfoSpecific, 1);
 779     spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
 780     spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
 781     *spec_info->u.luks.data = info->u.luks;
 782
 783     /* Blank out pointers we've just stolen to avoid double free */
 784     memset(&info->u.luks, 0, sizeof(info->u.luks));
 785
 786     qapi_free_QCryptoBlockInfo(info);
 787
 788     return spec_info;
 789 }
 790
 791 static int
 792 block_crypto_amend_options_generic_luks(BlockDriverState *bs,
 793                                         QCryptoBlockAmendOptions *amend_options,
 794                                         bool force,
 795                                         Error **errp)
 796 {
 797     BlockCrypto *crypto = bs->opaque;
 798     int ret;
 799
 800     assert(crypto);
 801     assert(crypto->block);
 802
 803     /* apply for exclusive read/write permissions to the underlying file*/
 804     crypto->updating_keys = true;
 805     ret = bdrv_child_refresh_perms(bs, bs->file, errp);
 806     if (ret) {
 807         goto cleanup;
 808     }
 809
 810     ret = qcrypto_block_amend_options(crypto->block,
 811                                       block_crypto_read_func,
 812                                       block_crypto_write_func,
 813                                       bs,
 814                                       amend_options,
 815                                       force,
 816                                       errp);
 817 cleanup:
 818     /* release exclusive read/write permissions to the underlying file*/
 819     crypto->updating_keys = false;
 820     bdrv_child_refresh_perms(bs, bs->file, errp);
 821     return ret;
 822 }
 823
 824 static int
 825 block_crypto_amend_options_luks(BlockDriverState *bs,
 826                                 QemuOpts *opts,
 827                                 BlockDriverAmendStatusCB *status_cb,
 828                                 void *cb_opaque,
 829                                 bool force,
 830                                 Error **errp)
 831 {
 832     BlockCrypto *crypto = bs->opaque;
 833     QDict *cryptoopts = NULL;
 834     QCryptoBlockAmendOptions *amend_options = NULL;
 835     int ret = -EINVAL;
 836
 837     assert(crypto);
 838     assert(crypto->block);
 839
 840     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 841     qdict_put_str(cryptoopts, "format", "luks");
 842     amend_options = block_crypto_amend_opts_init(cryptoopts, errp);
 843     qobject_unref(cryptoopts);
 844     if (!amend_options) {
 845         goto cleanup;
 846     }
 847     ret = block_crypto_amend_options_generic_luks(bs, amend_options,
 848                                                   force, errp);
 849 cleanup:
 850     qapi_free_QCryptoBlockAmendOptions(amend_options);
 851     return ret;
 852 }
 853
 854 static int
 855 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs,
 856                                         BlockdevAmendOptions *opts,
 857                                         bool force,
 858                                         Error **errp)
 859 {
 860     QCryptoBlockAmendOptions amend_opts;
 861
 862     amend_opts = (QCryptoBlockAmendOptions) {
 863         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 864         .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks),
 865     };
 866     return block_crypto_amend_options_generic_luks(bs, &amend_opts,
 867                                                    force, errp);
 868 }
 869
 870 static void
 871 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c,
 872                          const BdrvChildRole role,
 873                          BlockReopenQueue *reopen_queue,
 874                          uint64_t perm, uint64_t shared,
 875                          uint64_t *nperm, uint64_t *nshared)
 876 {
 877
 878     BlockCrypto *crypto = bs->opaque;
 879
 880     bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared);
 881
 882     /*
 883      * For backward compatibility, manually share the write
 884      * and resize permission
 885      */
 886     *nshared |= (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 887     /*
 888      * Since we are not fully a format driver, don't always request
 889      * the read/resize permission but only when explicitly
 890      * requested
 891      */
 892     *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 893     *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 894
 895     /*
 896      * This driver doesn't modify LUKS metadata except
 897      * when updating the encryption slots.
 898      * Thus unlike a proper format driver we don't ask for
 899      * shared write/read permission. However we need it
 900      * when we are updating the keys, to ensure that only we
 901      * have access to the device.
 902      *
 903      * Encryption update will set the crypto->updating_keys
 904      * during that period and refresh permissions
 905      *
 906      */
 907     if (crypto->updating_keys) {
 908         /* need exclusive write access for header update */
 909         *nperm |= BLK_PERM_WRITE;
 910         /* unshare read and write permission */
 911         *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE);
 912     }
 913 }
 914
 915
 916 static const char *const block_crypto_strong_runtime_opts[] = {
 917     BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
 918
 919     NULL
 920 };
 921
 922 static BlockDriver bdrv_crypto_luks = {
 923     .format_name        = "luks",
 924     .instance_size      = sizeof(BlockCrypto),
 925     .bdrv_probe         = block_crypto_probe_luks,
 926     .bdrv_open          = block_crypto_open_luks,
 927     .bdrv_close         = block_crypto_close,
 928     .bdrv_child_perm    = block_crypto_child_perms,
 929     .bdrv_co_create     = block_crypto_co_create_luks,
 930     .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
 931     .bdrv_co_truncate   = block_crypto_co_truncate,
 932     .create_opts        = &block_crypto_create_opts_luks,
 933     .amend_opts         = &block_crypto_amend_opts_luks,
 934
 935     .bdrv_reopen_prepare = block_crypto_reopen_prepare,
 936     .bdrv_refresh_limits = block_crypto_refresh_limits,
 937     .bdrv_co_preadv     = block_crypto_co_preadv,
 938     .bdrv_co_pwritev    = block_crypto_co_pwritev,
 939     .bdrv_getlength     = block_crypto_getlength,
 940     .bdrv_measure       = block_crypto_measure,
 941     .bdrv_get_info      = block_crypto_get_info_luks,
 942     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 943     .bdrv_amend_options = block_crypto_amend_options_luks,
 944     .bdrv_co_amend      = block_crypto_co_amend_luks,
 945
 946     .is_format          = true,
 947
 948     .strong_runtime_opts = block_crypto_strong_runtime_opts,
 949 };
 950
 951 static void block_crypto_init(void)
 952 {
 953     bdrv_register(&bdrv_crypto_luks);
 954 }
 955
 956 block_init(block_crypto_init);