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 int 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, buflen, buf, 0);
  69     if (ret < 0) {
  70         error_setg_errno(errp, -ret, "Could not read encryption header");
  71         return ret;
  72     }
  73     return 0;
  74 }
  75
  76 static int 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, buflen, buf, 0);
  87     if (ret < 0) {
  88         error_setg_errno(errp, -ret, "Could not write encryption header");
  89         return ret;
  90     }
  91     return 0;
  92 }
  93
  94
  95 struct BlockCryptoCreateData {
  96     BlockBackend *blk;
  97     uint64_t size;
  98     PreallocMode prealloc;
  99 };
 100
 101
 102 static int 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, buflen, buf, 0);
 113     if (ret < 0) {
 114         error_setg_errno(errp, -ret, "Could not write encryption header");
 115         return ret;
 116     }
 117     return 0;
 118 }
 119
 120 static int 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 0;
 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;
 265     QCryptoBlockOpenOptions *open_opts = NULL;
 266     unsigned int cflags = 0;
 267     QDict *cryptoopts = NULL;
 268
 269     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
 270     if (ret < 0) {
 271         return ret;
 272     }
 273
 274     bs->supported_write_flags = BDRV_REQ_FUA &
 275         bs->file->bs->supported_write_flags;
 276
 277     opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort);
 278     if (!qemu_opts_absorb_qdict(opts, options, errp)) {
 279         ret = -EINVAL;
 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         ret = -EINVAL;
 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, int64_t offset, int64_t bytes,
 403                        QEMUIOVector *qiov, BdrvRequestFlags 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(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     flags &= ~BDRV_REQ_REGISTERED_BUF;
 477
 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) {
 731         bdrv_co_delete_file_noerr(bs);
 732     }
 733
 734     bdrv_unref(bs);
 735     qapi_free_QCryptoBlockCreateOptions(create_opts);
 736     qobject_unref(cryptoopts);
 737     return ret;
 738 }
 739
 740 static int block_crypto_get_info_luks(BlockDriverState *bs,
 741                                       BlockDriverInfo *bdi)
 742 {
 743     BlockDriverInfo subbdi;
 744     int ret;
 745
 746     ret = bdrv_get_info(bs->file->bs, &subbdi);
 747     if (ret != 0) {
 748         return ret;
 749     }
 750
 751     bdi->cluster_size = subbdi.cluster_size;
 752
 753     return 0;
 754 }
 755
 756 static ImageInfoSpecific *
 757 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp)
 758 {
 759     BlockCrypto *crypto = bs->opaque;
 760     ImageInfoSpecific *spec_info;
 761     QCryptoBlockInfo *info;
 762
 763     info = qcrypto_block_get_info(crypto->block, errp);
 764     if (!info) {
 765         return NULL;
 766     }
 767     assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS);
 768
 769     spec_info = g_new(ImageInfoSpecific, 1);
 770     spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
 771     spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
 772     *spec_info->u.luks.data = info->u.luks;
 773
 774     /* Blank out pointers we've just stolen to avoid double free */
 775     memset(&info->u.luks, 0, sizeof(info->u.luks));
 776
 777     qapi_free_QCryptoBlockInfo(info);
 778
 779     return spec_info;
 780 }
 781
 782 static int
 783 block_crypto_amend_prepare(BlockDriverState *bs, Error **errp)
 784 {
 785     BlockCrypto *crypto = bs->opaque;
 786     int ret;
 787
 788     /* apply for exclusive read/write permissions to the underlying file */
 789     crypto->updating_keys = true;
 790     ret = bdrv_child_refresh_perms(bs, bs->file, errp);
 791     if (ret < 0) {
 792         /* Well, in this case we will not be updating any keys */
 793         crypto->updating_keys = false;
 794     }
 795     return ret;
 796 }
 797
 798 static void
 799 block_crypto_amend_cleanup(BlockDriverState *bs)
 800 {
 801     BlockCrypto *crypto = bs->opaque;
 802     Error *errp = NULL;
 803
 804     /* release exclusive read/write permissions to the underlying file */
 805     crypto->updating_keys = false;
 806     bdrv_child_refresh_perms(bs, bs->file, &errp);
 807
 808     if (errp) {
 809         error_report_err(errp);
 810     }
 811 }
 812
 813 static int
 814 block_crypto_amend_options_generic_luks(BlockDriverState *bs,
 815                                         QCryptoBlockAmendOptions *amend_options,
 816                                         bool force,
 817                                         Error **errp)
 818 {
 819     BlockCrypto *crypto = bs->opaque;
 820
 821     assert(crypto);
 822     assert(crypto->block);
 823
 824     return qcrypto_block_amend_options(crypto->block,
 825                                        block_crypto_read_func,
 826                                        block_crypto_write_func,
 827                                        bs,
 828                                        amend_options,
 829                                        force,
 830                                        errp);
 831 }
 832
 833 static int
 834 block_crypto_amend_options_luks(BlockDriverState *bs,
 835                                 QemuOpts *opts,
 836                                 BlockDriverAmendStatusCB *status_cb,
 837                                 void *cb_opaque,
 838                                 bool force,
 839                                 Error **errp)
 840 {
 841     BlockCrypto *crypto = bs->opaque;
 842     QDict *cryptoopts = NULL;
 843     QCryptoBlockAmendOptions *amend_options = NULL;
 844     int ret = -EINVAL;
 845
 846     assert(crypto);
 847     assert(crypto->block);
 848
 849     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 850     qdict_put_str(cryptoopts, "format", "luks");
 851     amend_options = block_crypto_amend_opts_init(cryptoopts, errp);
 852     qobject_unref(cryptoopts);
 853     if (!amend_options) {
 854         goto cleanup;
 855     }
 856
 857     ret = block_crypto_amend_prepare(bs, errp);
 858     if (ret) {
 859         goto perm_cleanup;
 860     }
 861     ret = block_crypto_amend_options_generic_luks(bs, amend_options,
 862                                                   force, errp);
 863
 864 perm_cleanup:
 865     block_crypto_amend_cleanup(bs);
 866 cleanup:
 867     qapi_free_QCryptoBlockAmendOptions(amend_options);
 868     return ret;
 869 }
 870
 871 static int
 872 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs,
 873                                         BlockdevAmendOptions *opts,
 874                                         bool force,
 875                                         Error **errp)
 876 {
 877     QCryptoBlockAmendOptions amend_opts;
 878
 879     amend_opts = (QCryptoBlockAmendOptions) {
 880         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 881         .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks),
 882     };
 883     return block_crypto_amend_options_generic_luks(bs, &amend_opts,
 884                                                    force, errp);
 885 }
 886
 887 static void
 888 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c,
 889                          const BdrvChildRole role,
 890                          BlockReopenQueue *reopen_queue,
 891                          uint64_t perm, uint64_t shared,
 892                          uint64_t *nperm, uint64_t *nshared)
 893 {
 894
 895     BlockCrypto *crypto = bs->opaque;
 896
 897     bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared);
 898
 899     /*
 900      * For backward compatibility, manually share the write
 901      * and resize permission
 902      */
 903     *nshared |= shared & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 904     /*
 905      * Since we are not fully a format driver, don't always request
 906      * the read/resize permission but only when explicitly
 907      * requested
 908      */
 909     *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 910     *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 911
 912     /*
 913      * This driver doesn't modify LUKS metadata except
 914      * when updating the encryption slots.
 915      * Thus unlike a proper format driver we don't ask for
 916      * shared write/read permission. However we need it
 917      * when we are updating the keys, to ensure that only we
 918      * have access to the device.
 919      *
 920      * Encryption update will set the crypto->updating_keys
 921      * during that period and refresh permissions
 922      *
 923      */
 924     if (crypto->updating_keys) {
 925         /* need exclusive write access for header update */
 926         *nperm |= BLK_PERM_WRITE;
 927         /* unshare read and write permission */
 928         *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE);
 929     }
 930 }
 931
 932
 933 static const char *const block_crypto_strong_runtime_opts[] = {
 934     BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
 935
 936     NULL
 937 };
 938
 939 static BlockDriver bdrv_crypto_luks = {
 940     .format_name        = "luks",
 941     .instance_size      = sizeof(BlockCrypto),
 942     .bdrv_probe         = block_crypto_probe_luks,
 943     .bdrv_open          = block_crypto_open_luks,
 944     .bdrv_close         = block_crypto_close,
 945     .bdrv_child_perm    = block_crypto_child_perms,
 946     .bdrv_co_create     = block_crypto_co_create_luks,
 947     .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
 948     .bdrv_co_truncate   = block_crypto_co_truncate,
 949     .create_opts        = &block_crypto_create_opts_luks,
 950     .amend_opts         = &block_crypto_amend_opts_luks,
 951
 952     .bdrv_reopen_prepare = block_crypto_reopen_prepare,
 953     .bdrv_refresh_limits = block_crypto_refresh_limits,
 954     .bdrv_co_preadv     = block_crypto_co_preadv,
 955     .bdrv_co_pwritev    = block_crypto_co_pwritev,
 956     .bdrv_getlength     = block_crypto_getlength,
 957     .bdrv_measure       = block_crypto_measure,
 958     .bdrv_get_info      = block_crypto_get_info_luks,
 959     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 960     .bdrv_amend_options = block_crypto_amend_options_luks,
 961     .bdrv_co_amend      = block_crypto_co_amend_luks,
 962     .bdrv_amend_pre_run = block_crypto_amend_prepare,
 963     .bdrv_amend_clean   = block_crypto_amend_cleanup,
 964
 965     .is_format          = true,
 966
 967     .strong_runtime_opts = block_crypto_strong_runtime_opts,
 968 };
 969
 970 static void block_crypto_init(void)
 971 {
 972     bdrv_register(&bdrv_crypto_luks);
 973 }
 974
 975 block_init(block_crypto_init);