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 2.1 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 "qemu/memalign.h"
  35 #include "crypto.h"
  36
  37 typedef struct BlockCrypto BlockCrypto;
  38
  39 struct BlockCrypto {
  40     QCryptoBlock *block;
  41     bool updating_keys;
  42 };
  43
  44
  45 static int block_crypto_probe_generic(QCryptoBlockFormat format,
  46                                       const uint8_t *buf,
  47                                       int buf_size,
  48                                       const char *filename)
  49 {
  50     if (qcrypto_block_has_format(format, buf, buf_size)) {
  51         return 100;
  52     } else {
  53         return 0;
  54     }
  55 }
  56
  57
  58 static ssize_t block_crypto_read_func(QCryptoBlock *block,
  59                                       size_t offset,
  60                                       uint8_t *buf,
  61                                       size_t buflen,
  62                                       void *opaque,
  63                                       Error **errp)
  64 {
  65     BlockDriverState *bs = opaque;
  66     ssize_t ret;
  67
  68     ret = bdrv_pread(bs->file, offset, buf, buflen);
  69     if (ret < 0) {
  70         error_setg_errno(errp, -ret, "Could not read encryption header");
  71         return ret;
  72     }
  73     return ret;
  74 }
  75
  76 static ssize_t block_crypto_write_func(QCryptoBlock *block,
  77                                        size_t offset,
  78                                        const uint8_t *buf,
  79                                        size_t buflen,
  80                                        void *opaque,
  81                                        Error **errp)
  82 {
  83     BlockDriverState *bs = opaque;
  84     ssize_t ret;
  85
  86     ret = bdrv_pwrite(bs->file, offset, buf, buflen);
  87     if (ret < 0) {
  88         error_setg_errno(errp, -ret, "Could not write encryption header");
  89         return ret;
  90     }
  91     return ret;
  92 }
  93
  94
  95 struct BlockCryptoCreateData {
  96     BlockBackend *blk;
  97     uint64_t size;
  98     PreallocMode prealloc;
  99 };
 100
 101
 102 static ssize_t block_crypto_create_write_func(QCryptoBlock *block,
 103                                               size_t offset,
 104                                               const uint8_t *buf,
 105                                               size_t buflen,
 106                                               void *opaque,
 107                                               Error **errp)
 108 {
 109     struct BlockCryptoCreateData *data = opaque;
 110     ssize_t ret;
 111
 112     ret = blk_pwrite(data->blk, offset, buf, buflen, 0);
 113     if (ret < 0) {
 114         error_setg_errno(errp, -ret, "Could not write encryption header");
 115         return ret;
 116     }
 117     return ret;
 118 }
 119
 120 static ssize_t block_crypto_create_init_func(QCryptoBlock *block,
 121                                              size_t headerlen,
 122                                              void *opaque,
 123                                              Error **errp)
 124 {
 125     struct BlockCryptoCreateData *data = opaque;
 126     Error *local_error = NULL;
 127     int ret;
 128
 129     if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) {
 130         ret = -EFBIG;
 131         goto error;
 132     }
 133
 134     /* User provided size should reflect amount of space made
 135      * available to the guest, so we must take account of that
 136      * which will be used by the crypto header
 137      */
 138     ret = blk_truncate(data->blk, data->size + headerlen, false,
 139                        data->prealloc, 0, &local_error);
 140
 141     if (ret >= 0) {
 142         return ret;
 143     }
 144
 145 error:
 146     if (ret == -EFBIG) {
 147         /* Replace the error message with a better one */
 148         error_free(local_error);
 149         error_setg(errp, "The requested file size is too large");
 150     } else {
 151         error_propagate(errp, local_error);
 152     }
 153
 154     return ret;
 155 }
 156
 157
 158 static QemuOptsList block_crypto_runtime_opts_luks = {
 159     .name = "crypto",
 160     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head),
 161     .desc = {
 162         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 163         { /* end of list */ }
 164     },
 165 };
 166
 167
 168 static QemuOptsList block_crypto_create_opts_luks = {
 169     .name = "crypto",
 170     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head),
 171     .desc = {
 172         {
 173             .name = BLOCK_OPT_SIZE,
 174             .type = QEMU_OPT_SIZE,
 175             .help = "Virtual disk size"
 176         },
 177         BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""),
 178         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""),
 179         BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""),
 180         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""),
 181         BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""),
 182         BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""),
 183         BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""),
 184         { /* end of list */ }
 185     },
 186 };
 187
 188
 189 static QemuOptsList block_crypto_amend_opts_luks = {
 190     .name = "crypto",
 191     .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head),
 192     .desc = {
 193         BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(""),
 194         BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(""),
 195         BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(""),
 196         BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(""),
 197         BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""),
 198         { /* end of list */ }
 199     },
 200 };
 201
 202 QCryptoBlockOpenOptions *
 203 block_crypto_open_opts_init(QDict *opts, Error **errp)
 204 {
 205     Visitor *v;
 206     QCryptoBlockOpenOptions *ret;
 207
 208     v = qobject_input_visitor_new_flat_confused(opts, errp);
 209     if (!v) {
 210         return NULL;
 211     }
 212
 213     visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp);
 214
 215     visit_free(v);
 216     return ret;
 217 }
 218
 219
 220 QCryptoBlockCreateOptions *
 221 block_crypto_create_opts_init(QDict *opts, Error **errp)
 222 {
 223     Visitor *v;
 224     QCryptoBlockCreateOptions *ret;
 225
 226     v = qobject_input_visitor_new_flat_confused(opts, errp);
 227     if (!v) {
 228         return NULL;
 229     }
 230
 231     visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp);
 232
 233     visit_free(v);
 234     return ret;
 235 }
 236
 237 QCryptoBlockAmendOptions *
 238 block_crypto_amend_opts_init(QDict *opts, Error **errp)
 239 {
 240     Visitor *v;
 241     QCryptoBlockAmendOptions *ret;
 242
 243     v = qobject_input_visitor_new_flat_confused(opts, errp);
 244     if (!v) {
 245         return NULL;
 246     }
 247
 248     visit_type_QCryptoBlockAmendOptions(v, NULL, &ret, errp);
 249
 250     visit_free(v);
 251     return ret;
 252 }
 253
 254
 255 static int block_crypto_open_generic(QCryptoBlockFormat format,
 256                                      QemuOptsList *opts_spec,
 257                                      BlockDriverState *bs,
 258                                      QDict *options,
 259                                      int flags,
 260                                      Error **errp)
 261 {
 262     BlockCrypto *crypto = bs->opaque;
 263     QemuOpts *opts = 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, errp)) {
 280         goto cleanup;
 281     }
 282
 283     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 284     qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format));
 285
 286     open_opts = block_crypto_open_opts_init(cryptoopts, errp);
 287     if (!open_opts) {
 288         goto cleanup;
 289     }
 290
 291     if (flags & BDRV_O_NO_IO) {
 292         cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 293     }
 294     crypto->block = qcrypto_block_open(open_opts, NULL,
 295                                        block_crypto_read_func,
 296                                        bs,
 297                                        cflags,
 298                                        1,
 299                                        errp);
 300
 301     if (!crypto->block) {
 302         ret = -EIO;
 303         goto cleanup;
 304     }
 305
 306     bs->encrypted = true;
 307
 308     ret = 0;
 309  cleanup:
 310     qobject_unref(cryptoopts);
 311     qapi_free_QCryptoBlockOpenOptions(open_opts);
 312     return ret;
 313 }
 314
 315
 316 static int block_crypto_co_create_generic(BlockDriverState *bs,
 317                                           int64_t size,
 318                                           QCryptoBlockCreateOptions *opts,
 319                                           PreallocMode prealloc,
 320                                           Error **errp)
 321 {
 322     int ret;
 323     BlockBackend *blk;
 324     QCryptoBlock *crypto = NULL;
 325     struct BlockCryptoCreateData data;
 326
 327     blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
 328                           errp);
 329     if (!blk) {
 330         ret = -EPERM;
 331         goto cleanup;
 332     }
 333
 334     if (prealloc == PREALLOC_MODE_METADATA) {
 335         prealloc = PREALLOC_MODE_OFF;
 336     }
 337
 338     data = (struct BlockCryptoCreateData) {
 339         .blk = blk,
 340         .size = size,
 341         .prealloc = prealloc,
 342     };
 343
 344     crypto = qcrypto_block_create(opts, NULL,
 345                                   block_crypto_create_init_func,
 346                                   block_crypto_create_write_func,
 347                                   &data,
 348                                   errp);
 349
 350     if (!crypto) {
 351         ret = -EIO;
 352         goto cleanup;
 353     }
 354
 355     ret = 0;
 356  cleanup:
 357     qcrypto_block_free(crypto);
 358     blk_unref(blk);
 359     return ret;
 360 }
 361
 362 static int coroutine_fn
 363 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 364                          PreallocMode prealloc, BdrvRequestFlags flags,
 365                          Error **errp)
 366 {
 367     BlockCrypto *crypto = bs->opaque;
 368     uint64_t payload_offset =
 369         qcrypto_block_get_payload_offset(crypto->block);
 370
 371     if (payload_offset > INT64_MAX - offset) {
 372         error_setg(errp, "The requested file size is too large");
 373         return -EFBIG;
 374     }
 375
 376     offset += payload_offset;
 377
 378     return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp);
 379 }
 380
 381 static void block_crypto_close(BlockDriverState *bs)
 382 {
 383     BlockCrypto *crypto = bs->opaque;
 384     qcrypto_block_free(crypto->block);
 385 }
 386
 387 static int block_crypto_reopen_prepare(BDRVReopenState *state,
 388                                        BlockReopenQueue *queue, Error **errp)
 389 {
 390     /* nothing needs checking */
 391     return 0;
 392 }
 393
 394 /*
 395  * 1 MB bounce buffer gives good performance / memory tradeoff
 396  * when using cache=none|directsync.
 397  */
 398 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024)
 399
 400 static coroutine_fn int
 401 block_crypto_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
 402                        QEMUIOVector *qiov, BdrvRequestFlags flags)
 403 {
 404     BlockCrypto *crypto = bs->opaque;
 405     uint64_t cur_bytes; /* number of bytes in current iteration */
 406     uint64_t bytes_done = 0;
 407     uint8_t *cipher_data = NULL;
 408     QEMUIOVector hd_qiov;
 409     int ret = 0;
 410     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 411     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 412
 413     assert(!flags);
 414     assert(payload_offset < INT64_MAX);
 415     assert(QEMU_IS_ALIGNED(offset, sector_size));
 416     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 417
 418     qemu_iovec_init(&hd_qiov, qiov->niov);
 419
 420     /* Bounce buffer because we don't wish to expose cipher text
 421      * in qiov which points to guest memory.
 422      */
 423     cipher_data =
 424         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 425                                               qiov->size));
 426     if (cipher_data == NULL) {
 427         ret = -ENOMEM;
 428         goto cleanup;
 429     }
 430
 431     while (bytes) {
 432         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 433
 434         qemu_iovec_reset(&hd_qiov);
 435         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 436
 437         ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done,
 438                              cur_bytes, &hd_qiov, 0);
 439         if (ret < 0) {
 440             goto cleanup;
 441         }
 442
 443         if (qcrypto_block_decrypt(crypto->block, offset + bytes_done,
 444                                   cipher_data, cur_bytes, NULL) < 0) {
 445             ret = -EIO;
 446             goto cleanup;
 447         }
 448
 449         qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes);
 450
 451         bytes -= cur_bytes;
 452         bytes_done += cur_bytes;
 453     }
 454
 455  cleanup:
 456     qemu_iovec_destroy(&hd_qiov);
 457     qemu_vfree(cipher_data);
 458
 459     return ret;
 460 }
 461
 462
 463 static coroutine_fn int
 464 block_crypto_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
 465                         QEMUIOVector *qiov, BdrvRequestFlags flags)
 466 {
 467     BlockCrypto *crypto = bs->opaque;
 468     uint64_t cur_bytes; /* number of bytes in current iteration */
 469     uint64_t bytes_done = 0;
 470     uint8_t *cipher_data = NULL;
 471     QEMUIOVector hd_qiov;
 472     int ret = 0;
 473     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 474     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 475
 476     assert(!(flags & ~BDRV_REQ_FUA));
 477     assert(payload_offset < INT64_MAX);
 478     assert(QEMU_IS_ALIGNED(offset, sector_size));
 479     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 480
 481     qemu_iovec_init(&hd_qiov, qiov->niov);
 482
 483     /* Bounce buffer because we're not permitted to touch
 484      * contents of qiov - it points to guest memory.
 485      */
 486     cipher_data =
 487         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 488                                               qiov->size));
 489     if (cipher_data == NULL) {
 490         ret = -ENOMEM;
 491         goto cleanup;
 492     }
 493
 494     while (bytes) {
 495         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 496
 497         qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes);
 498
 499         if (qcrypto_block_encrypt(crypto->block, offset + bytes_done,
 500                                   cipher_data, cur_bytes, NULL) < 0) {
 501             ret = -EIO;
 502             goto cleanup;
 503         }
 504
 505         qemu_iovec_reset(&hd_qiov);
 506         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 507
 508         ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done,
 509                               cur_bytes, &hd_qiov, flags);
 510         if (ret < 0) {
 511             goto cleanup;
 512         }
 513
 514         bytes -= cur_bytes;
 515         bytes_done += cur_bytes;
 516     }
 517
 518  cleanup:
 519     qemu_iovec_destroy(&hd_qiov);
 520     qemu_vfree(cipher_data);
 521
 522     return ret;
 523 }
 524
 525 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp)
 526 {
 527     BlockCrypto *crypto = bs->opaque;
 528     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 529     bs->bl.request_alignment = sector_size; /* No sub-sector I/O */
 530 }
 531
 532
 533 static int64_t block_crypto_getlength(BlockDriverState *bs)
 534 {
 535     BlockCrypto *crypto = bs->opaque;
 536     int64_t len = bdrv_getlength(bs->file->bs);
 537
 538     uint64_t offset = qcrypto_block_get_payload_offset(crypto->block);
 539     assert(offset < INT64_MAX);
 540
 541     if (offset > len) {
 542         return -EIO;
 543     }
 544
 545     len -= offset;
 546
 547     return len;
 548 }
 549
 550
 551 static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts,
 552                                               BlockDriverState *in_bs,
 553                                               Error **errp)
 554 {
 555     g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
 556     Error *local_err = NULL;
 557     BlockMeasureInfo *info;
 558     uint64_t size;
 559     size_t luks_payload_size;
 560     QDict *cryptoopts;
 561
 562     /*
 563      * Preallocation mode doesn't affect size requirements but we must consume
 564      * the option.
 565      */
 566     g_free(qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC));
 567
 568     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 569
 570     if (in_bs) {
 571         int64_t ssize = bdrv_getlength(in_bs);
 572
 573         if (ssize < 0) {
 574             error_setg_errno(&local_err, -ssize,
 575                              "Unable to get image virtual_size");
 576             goto err;
 577         }
 578
 579         size = ssize;
 580     }
 581
 582     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 583             &block_crypto_create_opts_luks, true);
 584     qdict_put_str(cryptoopts, "format", "luks");
 585     create_opts = block_crypto_create_opts_init(cryptoopts, &local_err);
 586     qobject_unref(cryptoopts);
 587     if (!create_opts) {
 588         goto err;
 589     }
 590
 591     if (!qcrypto_block_calculate_payload_offset(create_opts, NULL,
 592                                                 &luks_payload_size,
 593                                                 &local_err)) {
 594         goto err;
 595     }
 596
 597     /*
 598      * Unallocated blocks are still encrypted so allocation status makes no
 599      * difference to the file size.
 600      */
 601     info = g_new0(BlockMeasureInfo, 1);
 602     info->fully_allocated = luks_payload_size + size;
 603     info->required = luks_payload_size + size;
 604     return info;
 605
 606 err:
 607     error_propagate(errp, local_err);
 608     return NULL;
 609 }
 610
 611
 612 static int block_crypto_probe_luks(const uint8_t *buf,
 613                                    int buf_size,
 614                                    const char *filename) {
 615     return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 616                                       buf, buf_size, filename);
 617 }
 618
 619 static int block_crypto_open_luks(BlockDriverState *bs,
 620                                   QDict *options,
 621                                   int flags,
 622                                   Error **errp)
 623 {
 624     return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 625                                      &block_crypto_runtime_opts_luks,
 626                                      bs, options, flags, errp);
 627 }
 628
 629 static int coroutine_fn
 630 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
 631 {
 632     BlockdevCreateOptionsLUKS *luks_opts;
 633     BlockDriverState *bs = NULL;
 634     QCryptoBlockCreateOptions create_opts;
 635     PreallocMode preallocation = PREALLOC_MODE_OFF;
 636     int ret;
 637
 638     assert(create_options->driver == BLOCKDEV_DRIVER_LUKS);
 639     luks_opts = &create_options->u.luks;
 640
 641     bs = bdrv_open_blockdev_ref(luks_opts->file, errp);
 642     if (bs == NULL) {
 643         return -EIO;
 644     }
 645
 646     create_opts = (QCryptoBlockCreateOptions) {
 647         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 648         .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts),
 649     };
 650
 651     if (luks_opts->has_preallocation) {
 652         preallocation = luks_opts->preallocation;
 653     }
 654
 655     ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
 656                                          preallocation, errp);
 657     if (ret < 0) {
 658         goto fail;
 659     }
 660
 661     ret = 0;
 662 fail:
 663     bdrv_unref(bs);
 664     return ret;
 665 }
 666
 667 static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv,
 668                                                          const char *filename,
 669                                                          QemuOpts *opts,
 670                                                          Error **errp)
 671 {
 672     QCryptoBlockCreateOptions *create_opts = NULL;
 673     BlockDriverState *bs = NULL;
 674     QDict *cryptoopts;
 675     PreallocMode prealloc;
 676     char *buf = NULL;
 677     int64_t size;
 678     int ret;
 679     Error *local_err = NULL;
 680
 681     /* Parse options */
 682     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 683
 684     buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
 685     prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
 686                                PREALLOC_MODE_OFF, &local_err);
 687     g_free(buf);
 688     if (local_err) {
 689         error_propagate(errp, local_err);
 690         return -EINVAL;
 691     }
 692
 693     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 694                                              &block_crypto_create_opts_luks,
 695                                              true);
 696
 697     qdict_put_str(cryptoopts, "format", "luks");
 698     create_opts = block_crypto_create_opts_init(cryptoopts, errp);
 699     if (!create_opts) {
 700         ret = -EINVAL;
 701         goto fail;
 702     }
 703
 704     /* Create protocol layer */
 705     ret = bdrv_create_file(filename, opts, errp);
 706     if (ret < 0) {
 707         goto fail;
 708     }
 709
 710     bs = bdrv_open(filename, NULL, NULL,
 711                    BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 712     if (!bs) {
 713         ret = -EINVAL;
 714         goto fail;
 715     }
 716
 717     /* Create format layer */
 718     ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp);
 719     if (ret < 0) {
 720         goto fail;
 721     }
 722
 723     ret = 0;
 724 fail:
 725     /*
 726      * If an error occurred, delete 'filename'. Even if the file existed
 727      * beforehand, it has been truncated and corrupted in the process.
 728      */
 729     if (ret) {
 730         bdrv_co_delete_file_noerr(bs);
 731     }
 732
 733     bdrv_unref(bs);
 734     qapi_free_QCryptoBlockCreateOptions(create_opts);
 735     qobject_unref(cryptoopts);
 736     return ret;
 737 }
 738
 739 static int block_crypto_get_info_luks(BlockDriverState *bs,
 740                                       BlockDriverInfo *bdi)
 741 {
 742     BlockDriverInfo subbdi;
 743     int ret;
 744
 745     ret = bdrv_get_info(bs->file->bs, &subbdi);
 746     if (ret != 0) {
 747         return ret;
 748     }
 749
 750     bdi->cluster_size = subbdi.cluster_size;
 751
 752     return 0;
 753 }
 754
 755 static ImageInfoSpecific *
 756 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp)
 757 {
 758     BlockCrypto *crypto = bs->opaque;
 759     ImageInfoSpecific *spec_info;
 760     QCryptoBlockInfo *info;
 761
 762     info = qcrypto_block_get_info(crypto->block, errp);
 763     if (!info) {
 764         return NULL;
 765     }
 766     assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS);
 767
 768     spec_info = g_new(ImageInfoSpecific, 1);
 769     spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
 770     spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
 771     *spec_info->u.luks.data = info->u.luks;
 772
 773     /* Blank out pointers we've just stolen to avoid double free */
 774     memset(&info->u.luks, 0, sizeof(info->u.luks));
 775
 776     qapi_free_QCryptoBlockInfo(info);
 777
 778     return spec_info;
 779 }
 780
 781 static int
 782 block_crypto_amend_prepare(BlockDriverState *bs, Error **errp)
 783 {
 784     BlockCrypto *crypto = bs->opaque;
 785     int ret;
 786
 787     /* apply for exclusive read/write permissions to the underlying file */
 788     crypto->updating_keys = true;
 789     ret = bdrv_child_refresh_perms(bs, bs->file, errp);
 790     if (ret < 0) {
 791         /* Well, in this case we will not be updating any keys */
 792         crypto->updating_keys = false;
 793     }
 794     return ret;
 795 }
 796
 797 static void
 798 block_crypto_amend_cleanup(BlockDriverState *bs)
 799 {
 800     BlockCrypto *crypto = bs->opaque;
 801     Error *errp = NULL;
 802
 803     /* release exclusive read/write permissions to the underlying file */
 804     crypto->updating_keys = false;
 805     bdrv_child_refresh_perms(bs, bs->file, &errp);
 806
 807     if (errp) {
 808         error_report_err(errp);
 809     }
 810 }
 811
 812 static int
 813 block_crypto_amend_options_generic_luks(BlockDriverState *bs,
 814                                         QCryptoBlockAmendOptions *amend_options,
 815                                         bool force,
 816                                         Error **errp)
 817 {
 818     BlockCrypto *crypto = bs->opaque;
 819
 820     assert(crypto);
 821     assert(crypto->block);
 822
 823     return qcrypto_block_amend_options(crypto->block,
 824                                        block_crypto_read_func,
 825                                        block_crypto_write_func,
 826                                        bs,
 827                                        amend_options,
 828                                        force,
 829                                        errp);
 830 }
 831
 832 static int
 833 block_crypto_amend_options_luks(BlockDriverState *bs,
 834                                 QemuOpts *opts,
 835                                 BlockDriverAmendStatusCB *status_cb,
 836                                 void *cb_opaque,
 837                                 bool force,
 838                                 Error **errp)
 839 {
 840     BlockCrypto *crypto = bs->opaque;
 841     QDict *cryptoopts = NULL;
 842     QCryptoBlockAmendOptions *amend_options = NULL;
 843     int ret = -EINVAL;
 844
 845     assert(crypto);
 846     assert(crypto->block);
 847
 848     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 849     qdict_put_str(cryptoopts, "format", "luks");
 850     amend_options = block_crypto_amend_opts_init(cryptoopts, errp);
 851     qobject_unref(cryptoopts);
 852     if (!amend_options) {
 853         goto cleanup;
 854     }
 855
 856     ret = block_crypto_amend_prepare(bs, errp);
 857     if (ret) {
 858         goto perm_cleanup;
 859     }
 860     ret = block_crypto_amend_options_generic_luks(bs, amend_options,
 861                                                   force, errp);
 862
 863 perm_cleanup:
 864     block_crypto_amend_cleanup(bs);
 865 cleanup:
 866     qapi_free_QCryptoBlockAmendOptions(amend_options);
 867     return ret;
 868 }
 869
 870 static int
 871 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs,
 872                                         BlockdevAmendOptions *opts,
 873                                         bool force,
 874                                         Error **errp)
 875 {
 876     QCryptoBlockAmendOptions amend_opts;
 877
 878     amend_opts = (QCryptoBlockAmendOptions) {
 879         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 880         .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks),
 881     };
 882     return block_crypto_amend_options_generic_luks(bs, &amend_opts,
 883                                                    force, errp);
 884 }
 885
 886 static void
 887 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c,
 888                          const BdrvChildRole role,
 889                          BlockReopenQueue *reopen_queue,
 890                          uint64_t perm, uint64_t shared,
 891                          uint64_t *nperm, uint64_t *nshared)
 892 {
 893
 894     BlockCrypto *crypto = bs->opaque;
 895
 896     bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared);
 897
 898     /*
 899      * For backward compatibility, manually share the write
 900      * and resize permission
 901      */
 902     *nshared |= shared & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 903     /*
 904      * Since we are not fully a format driver, don't always request
 905      * the read/resize permission but only when explicitly
 906      * requested
 907      */
 908     *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 909     *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 910
 911     /*
 912      * This driver doesn't modify LUKS metadata except
 913      * when updating the encryption slots.
 914      * Thus unlike a proper format driver we don't ask for
 915      * shared write/read permission. However we need it
 916      * when we are updating the keys, to ensure that only we
 917      * have access to the device.
 918      *
 919      * Encryption update will set the crypto->updating_keys
 920      * during that period and refresh permissions
 921      *
 922      */
 923     if (crypto->updating_keys) {
 924         /* need exclusive write access for header update */
 925         *nperm |= BLK_PERM_WRITE;
 926         /* unshare read and write permission */
 927         *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE);
 928     }
 929 }
 930
 931
 932 static const char *const block_crypto_strong_runtime_opts[] = {
 933     BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
 934
 935     NULL
 936 };
 937
 938 static BlockDriver bdrv_crypto_luks = {
 939     .format_name        = "luks",
 940     .instance_size      = sizeof(BlockCrypto),
 941     .bdrv_probe         = block_crypto_probe_luks,
 942     .bdrv_open          = block_crypto_open_luks,
 943     .bdrv_close         = block_crypto_close,
 944     .bdrv_child_perm    = block_crypto_child_perms,
 945     .bdrv_co_create     = block_crypto_co_create_luks,
 946     .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
 947     .bdrv_co_truncate   = block_crypto_co_truncate,
 948     .create_opts        = &block_crypto_create_opts_luks,
 949     .amend_opts         = &block_crypto_amend_opts_luks,
 950
 951     .bdrv_reopen_prepare = block_crypto_reopen_prepare,
 952     .bdrv_refresh_limits = block_crypto_refresh_limits,
 953     .bdrv_co_preadv     = block_crypto_co_preadv,
 954     .bdrv_co_pwritev    = block_crypto_co_pwritev,
 955     .bdrv_getlength     = block_crypto_getlength,
 956     .bdrv_measure       = block_crypto_measure,
 957     .bdrv_get_info      = block_crypto_get_info_luks,
 958     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 959     .bdrv_amend_options = block_crypto_amend_options_luks,
 960     .bdrv_co_amend      = block_crypto_co_amend_luks,
 961     .bdrv_amend_pre_run = block_crypto_amend_prepare,
 962     .bdrv_amend_clean   = block_crypto_amend_cleanup,
 963
 964     .is_format          = true,
 965
 966     .strong_runtime_opts = block_crypto_strong_runtime_opts,
 967 };
 968
 969 static void block_crypto_init(void)
 970 {
 971     bdrv_register(&bdrv_crypto_luks);
 972 }
 973
 974 block_init(block_crypto_init);