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     qemu_opts_absorb_qdict(opts, options, &local_err);
 280     if (local_err) {
 281         error_propagate(errp, local_err);
 282         goto cleanup;
 283     }
 284
 285     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 286     qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format));
 287
 288     open_opts = block_crypto_open_opts_init(cryptoopts, errp);
 289     if (!open_opts) {
 290         goto cleanup;
 291     }
 292
 293     if (flags & BDRV_O_NO_IO) {
 294         cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 295     }
 296     crypto->block = qcrypto_block_open(open_opts, NULL,
 297                                        block_crypto_read_func,
 298                                        bs,
 299                                        cflags,
 300                                        1,
 301                                        errp);
 302
 303     if (!crypto->block) {
 304         ret = -EIO;
 305         goto cleanup;
 306     }
 307
 308     bs->encrypted = true;
 309
 310     ret = 0;
 311  cleanup:
 312     qobject_unref(cryptoopts);
 313     qapi_free_QCryptoBlockOpenOptions(open_opts);
 314     return ret;
 315 }
 316
 317
 318 static int block_crypto_co_create_generic(BlockDriverState *bs,
 319                                           int64_t size,
 320                                           QCryptoBlockCreateOptions *opts,
 321                                           PreallocMode prealloc,
 322                                           Error **errp)
 323 {
 324     int ret;
 325     BlockBackend *blk;
 326     QCryptoBlock *crypto = NULL;
 327     struct BlockCryptoCreateData data;
 328
 329     blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL,
 330                           errp);
 331     if (!blk) {
 332         ret = -EPERM;
 333         goto cleanup;
 334     }
 335
 336     if (prealloc == PREALLOC_MODE_METADATA) {
 337         prealloc = PREALLOC_MODE_OFF;
 338     }
 339
 340     data = (struct BlockCryptoCreateData) {
 341         .blk = blk,
 342         .size = size,
 343         .prealloc = prealloc,
 344     };
 345
 346     crypto = qcrypto_block_create(opts, NULL,
 347                                   block_crypto_create_init_func,
 348                                   block_crypto_create_write_func,
 349                                   &data,
 350                                   errp);
 351
 352     if (!crypto) {
 353         ret = -EIO;
 354         goto cleanup;
 355     }
 356
 357     ret = 0;
 358  cleanup:
 359     qcrypto_block_free(crypto);
 360     blk_unref(blk);
 361     return ret;
 362 }
 363
 364 static int coroutine_fn
 365 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact,
 366                          PreallocMode prealloc, BdrvRequestFlags flags,
 367                          Error **errp)
 368 {
 369     BlockCrypto *crypto = bs->opaque;
 370     uint64_t payload_offset =
 371         qcrypto_block_get_payload_offset(crypto->block);
 372
 373     if (payload_offset > INT64_MAX - offset) {
 374         error_setg(errp, "The requested file size is too large");
 375         return -EFBIG;
 376     }
 377
 378     offset += payload_offset;
 379
 380     return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp);
 381 }
 382
 383 static void block_crypto_close(BlockDriverState *bs)
 384 {
 385     BlockCrypto *crypto = bs->opaque;
 386     qcrypto_block_free(crypto->block);
 387 }
 388
 389 static int block_crypto_reopen_prepare(BDRVReopenState *state,
 390                                        BlockReopenQueue *queue, Error **errp)
 391 {
 392     /* nothing needs checking */
 393     return 0;
 394 }
 395
 396 /*
 397  * 1 MB bounce buffer gives good performance / memory tradeoff
 398  * when using cache=none|directsync.
 399  */
 400 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024)
 401
 402 static coroutine_fn int
 403 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 404                        QEMUIOVector *qiov, int flags)
 405 {
 406     BlockCrypto *crypto = bs->opaque;
 407     uint64_t cur_bytes; /* number of bytes in current iteration */
 408     uint64_t bytes_done = 0;
 409     uint8_t *cipher_data = NULL;
 410     QEMUIOVector hd_qiov;
 411     int ret = 0;
 412     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 413     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 414
 415     assert(!flags);
 416     assert(payload_offset < INT64_MAX);
 417     assert(QEMU_IS_ALIGNED(offset, sector_size));
 418     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 419
 420     qemu_iovec_init(&hd_qiov, qiov->niov);
 421
 422     /* Bounce buffer because we don't wish to expose cipher text
 423      * in qiov which points to guest memory.
 424      */
 425     cipher_data =
 426         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 427                                               qiov->size));
 428     if (cipher_data == NULL) {
 429         ret = -ENOMEM;
 430         goto cleanup;
 431     }
 432
 433     while (bytes) {
 434         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 435
 436         qemu_iovec_reset(&hd_qiov);
 437         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 438
 439         ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done,
 440                              cur_bytes, &hd_qiov, 0);
 441         if (ret < 0) {
 442             goto cleanup;
 443         }
 444
 445         if (qcrypto_block_decrypt(crypto->block, offset + bytes_done,
 446                                   cipher_data, cur_bytes, NULL) < 0) {
 447             ret = -EIO;
 448             goto cleanup;
 449         }
 450
 451         qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes);
 452
 453         bytes -= cur_bytes;
 454         bytes_done += cur_bytes;
 455     }
 456
 457  cleanup:
 458     qemu_iovec_destroy(&hd_qiov);
 459     qemu_vfree(cipher_data);
 460
 461     return ret;
 462 }
 463
 464
 465 static coroutine_fn int
 466 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes,
 467                         QEMUIOVector *qiov, int flags)
 468 {
 469     BlockCrypto *crypto = bs->opaque;
 470     uint64_t cur_bytes; /* number of bytes in current iteration */
 471     uint64_t bytes_done = 0;
 472     uint8_t *cipher_data = NULL;
 473     QEMUIOVector hd_qiov;
 474     int ret = 0;
 475     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 476     uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block);
 477
 478     assert(!(flags & ~BDRV_REQ_FUA));
 479     assert(payload_offset < INT64_MAX);
 480     assert(QEMU_IS_ALIGNED(offset, sector_size));
 481     assert(QEMU_IS_ALIGNED(bytes, sector_size));
 482
 483     qemu_iovec_init(&hd_qiov, qiov->niov);
 484
 485     /* Bounce buffer because we're not permitted to touch
 486      * contents of qiov - it points to guest memory.
 487      */
 488     cipher_data =
 489         qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE,
 490                                               qiov->size));
 491     if (cipher_data == NULL) {
 492         ret = -ENOMEM;
 493         goto cleanup;
 494     }
 495
 496     while (bytes) {
 497         cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE);
 498
 499         qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes);
 500
 501         if (qcrypto_block_encrypt(crypto->block, offset + bytes_done,
 502                                   cipher_data, cur_bytes, NULL) < 0) {
 503             ret = -EIO;
 504             goto cleanup;
 505         }
 506
 507         qemu_iovec_reset(&hd_qiov);
 508         qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes);
 509
 510         ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done,
 511                               cur_bytes, &hd_qiov, flags);
 512         if (ret < 0) {
 513             goto cleanup;
 514         }
 515
 516         bytes -= cur_bytes;
 517         bytes_done += cur_bytes;
 518     }
 519
 520  cleanup:
 521     qemu_iovec_destroy(&hd_qiov);
 522     qemu_vfree(cipher_data);
 523
 524     return ret;
 525 }
 526
 527 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp)
 528 {
 529     BlockCrypto *crypto = bs->opaque;
 530     uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block);
 531     bs->bl.request_alignment = sector_size; /* No sub-sector I/O */
 532 }
 533
 534
 535 static int64_t block_crypto_getlength(BlockDriverState *bs)
 536 {
 537     BlockCrypto *crypto = bs->opaque;
 538     int64_t len = bdrv_getlength(bs->file->bs);
 539
 540     uint64_t offset = qcrypto_block_get_payload_offset(crypto->block);
 541     assert(offset < INT64_MAX);
 542
 543     if (offset > len) {
 544         return -EIO;
 545     }
 546
 547     len -= offset;
 548
 549     return len;
 550 }
 551
 552
 553 static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts,
 554                                               BlockDriverState *in_bs,
 555                                               Error **errp)
 556 {
 557     g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL;
 558     Error *local_err = NULL;
 559     BlockMeasureInfo *info;
 560     uint64_t size;
 561     size_t luks_payload_size;
 562     QDict *cryptoopts;
 563
 564     /*
 565      * Preallocation mode doesn't affect size requirements but we must consume
 566      * the option.
 567      */
 568     g_free(qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC));
 569
 570     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 571
 572     if (in_bs) {
 573         int64_t ssize = bdrv_getlength(in_bs);
 574
 575         if (ssize < 0) {
 576             error_setg_errno(&local_err, -ssize,
 577                              "Unable to get image virtual_size");
 578             goto err;
 579         }
 580
 581         size = ssize;
 582     }
 583
 584     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 585             &block_crypto_create_opts_luks, true);
 586     qdict_put_str(cryptoopts, "format", "luks");
 587     create_opts = block_crypto_create_opts_init(cryptoopts, &local_err);
 588     qobject_unref(cryptoopts);
 589     if (!create_opts) {
 590         goto err;
 591     }
 592
 593     if (!qcrypto_block_calculate_payload_offset(create_opts, NULL,
 594                                                 &luks_payload_size,
 595                                                 &local_err)) {
 596         goto err;
 597     }
 598
 599     /*
 600      * Unallocated blocks are still encrypted so allocation status makes no
 601      * difference to the file size.
 602      */
 603     info = g_new0(BlockMeasureInfo, 1);
 604     info->fully_allocated = luks_payload_size + size;
 605     info->required = luks_payload_size + size;
 606     return info;
 607
 608 err:
 609     error_propagate(errp, local_err);
 610     return NULL;
 611 }
 612
 613
 614 static int block_crypto_probe_luks(const uint8_t *buf,
 615                                    int buf_size,
 616                                    const char *filename) {
 617     return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 618                                       buf, buf_size, filename);
 619 }
 620
 621 static int block_crypto_open_luks(BlockDriverState *bs,
 622                                   QDict *options,
 623                                   int flags,
 624                                   Error **errp)
 625 {
 626     return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS,
 627                                      &block_crypto_runtime_opts_luks,
 628                                      bs, options, flags, errp);
 629 }
 630
 631 static int coroutine_fn
 632 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp)
 633 {
 634     BlockdevCreateOptionsLUKS *luks_opts;
 635     BlockDriverState *bs = NULL;
 636     QCryptoBlockCreateOptions create_opts;
 637     PreallocMode preallocation = PREALLOC_MODE_OFF;
 638     int ret;
 639
 640     assert(create_options->driver == BLOCKDEV_DRIVER_LUKS);
 641     luks_opts = &create_options->u.luks;
 642
 643     bs = bdrv_open_blockdev_ref(luks_opts->file, errp);
 644     if (bs == NULL) {
 645         return -EIO;
 646     }
 647
 648     create_opts = (QCryptoBlockCreateOptions) {
 649         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 650         .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts),
 651     };
 652
 653     if (luks_opts->has_preallocation) {
 654         preallocation = luks_opts->preallocation;
 655     }
 656
 657     ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts,
 658                                          preallocation, errp);
 659     if (ret < 0) {
 660         goto fail;
 661     }
 662
 663     ret = 0;
 664 fail:
 665     bdrv_unref(bs);
 666     return ret;
 667 }
 668
 669 static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv,
 670                                                          const char *filename,
 671                                                          QemuOpts *opts,
 672                                                          Error **errp)
 673 {
 674     QCryptoBlockCreateOptions *create_opts = NULL;
 675     BlockDriverState *bs = NULL;
 676     QDict *cryptoopts;
 677     PreallocMode prealloc;
 678     char *buf = NULL;
 679     int64_t size;
 680     int ret;
 681     Error *local_err = NULL;
 682
 683     /* Parse options */
 684     size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
 685
 686     buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
 687     prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
 688                                PREALLOC_MODE_OFF, &local_err);
 689     g_free(buf);
 690     if (local_err) {
 691         error_propagate(errp, local_err);
 692         return -EINVAL;
 693     }
 694
 695     cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL,
 696                                              &block_crypto_create_opts_luks,
 697                                              true);
 698
 699     qdict_put_str(cryptoopts, "format", "luks");
 700     create_opts = block_crypto_create_opts_init(cryptoopts, errp);
 701     if (!create_opts) {
 702         ret = -EINVAL;
 703         goto fail;
 704     }
 705
 706     /* Create protocol layer */
 707     ret = bdrv_create_file(filename, opts, errp);
 708     if (ret < 0) {
 709         goto fail;
 710     }
 711
 712     bs = bdrv_open(filename, NULL, NULL,
 713                    BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 714     if (!bs) {
 715         ret = -EINVAL;
 716         goto fail;
 717     }
 718
 719     /* Create format layer */
 720     ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp);
 721     if (ret < 0) {
 722         goto fail;
 723     }
 724
 725     ret = 0;
 726 fail:
 727     /*
 728      * If an error occurred, delete 'filename'. Even if the file existed
 729      * beforehand, it has been truncated and corrupted in the process.
 730      */
 731     if (ret && bs) {
 732         Error *local_delete_err = NULL;
 733         int r_del = bdrv_co_delete_file(bs, &local_delete_err);
 734         /*
 735          * ENOTSUP will happen if the block driver doesn't support
 736          * the 'bdrv_co_delete_file' interface. This is a predictable
 737          * scenario and shouldn't be reported back to the user.
 738          */
 739         if ((r_del < 0) && (r_del != -ENOTSUP)) {
 740             error_report_err(local_delete_err);
 741         }
 742     }
 743
 744     bdrv_unref(bs);
 745     qapi_free_QCryptoBlockCreateOptions(create_opts);
 746     qobject_unref(cryptoopts);
 747     return ret;
 748 }
 749
 750 static int block_crypto_get_info_luks(BlockDriverState *bs,
 751                                       BlockDriverInfo *bdi)
 752 {
 753     BlockDriverInfo subbdi;
 754     int ret;
 755
 756     ret = bdrv_get_info(bs->file->bs, &subbdi);
 757     if (ret != 0) {
 758         return ret;
 759     }
 760
 761     bdi->cluster_size = subbdi.cluster_size;
 762
 763     return 0;
 764 }
 765
 766 static ImageInfoSpecific *
 767 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp)
 768 {
 769     BlockCrypto *crypto = bs->opaque;
 770     ImageInfoSpecific *spec_info;
 771     QCryptoBlockInfo *info;
 772
 773     info = qcrypto_block_get_info(crypto->block, errp);
 774     if (!info) {
 775         return NULL;
 776     }
 777     assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS);
 778
 779     spec_info = g_new(ImageInfoSpecific, 1);
 780     spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS;
 781     spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1);
 782     *spec_info->u.luks.data = info->u.luks;
 783
 784     /* Blank out pointers we've just stolen to avoid double free */
 785     memset(&info->u.luks, 0, sizeof(info->u.luks));
 786
 787     qapi_free_QCryptoBlockInfo(info);
 788
 789     return spec_info;
 790 }
 791
 792 static int
 793 block_crypto_amend_options_generic_luks(BlockDriverState *bs,
 794                                         QCryptoBlockAmendOptions *amend_options,
 795                                         bool force,
 796                                         Error **errp)
 797 {
 798     BlockCrypto *crypto = bs->opaque;
 799     int ret;
 800
 801     assert(crypto);
 802     assert(crypto->block);
 803
 804     /* apply for exclusive read/write permissions to the underlying file*/
 805     crypto->updating_keys = true;
 806     ret = bdrv_child_refresh_perms(bs, bs->file, errp);
 807     if (ret) {
 808         goto cleanup;
 809     }
 810
 811     ret = qcrypto_block_amend_options(crypto->block,
 812                                       block_crypto_read_func,
 813                                       block_crypto_write_func,
 814                                       bs,
 815                                       amend_options,
 816                                       force,
 817                                       errp);
 818 cleanup:
 819     /* release exclusive read/write permissions to the underlying file*/
 820     crypto->updating_keys = false;
 821     bdrv_child_refresh_perms(bs, bs->file, errp);
 822     return ret;
 823 }
 824
 825 static int
 826 block_crypto_amend_options_luks(BlockDriverState *bs,
 827                                 QemuOpts *opts,
 828                                 BlockDriverAmendStatusCB *status_cb,
 829                                 void *cb_opaque,
 830                                 bool force,
 831                                 Error **errp)
 832 {
 833     BlockCrypto *crypto = bs->opaque;
 834     QDict *cryptoopts = NULL;
 835     QCryptoBlockAmendOptions *amend_options = NULL;
 836     int ret = -EINVAL;
 837
 838     assert(crypto);
 839     assert(crypto->block);
 840
 841     cryptoopts = qemu_opts_to_qdict(opts, NULL);
 842     qdict_put_str(cryptoopts, "format", "luks");
 843     amend_options = block_crypto_amend_opts_init(cryptoopts, errp);
 844     qobject_unref(cryptoopts);
 845     if (!amend_options) {
 846         goto cleanup;
 847     }
 848     ret = block_crypto_amend_options_generic_luks(bs, amend_options,
 849                                                   force, errp);
 850 cleanup:
 851     qapi_free_QCryptoBlockAmendOptions(amend_options);
 852     return ret;
 853 }
 854
 855 static int
 856 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs,
 857                                         BlockdevAmendOptions *opts,
 858                                         bool force,
 859                                         Error **errp)
 860 {
 861     QCryptoBlockAmendOptions amend_opts;
 862
 863     amend_opts = (QCryptoBlockAmendOptions) {
 864         .format = Q_CRYPTO_BLOCK_FORMAT_LUKS,
 865         .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks),
 866     };
 867     return block_crypto_amend_options_generic_luks(bs, &amend_opts,
 868                                                    force, errp);
 869 }
 870
 871 static void
 872 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c,
 873                          const BdrvChildRole role,
 874                          BlockReopenQueue *reopen_queue,
 875                          uint64_t perm, uint64_t shared,
 876                          uint64_t *nperm, uint64_t *nshared)
 877 {
 878
 879     BlockCrypto *crypto = bs->opaque;
 880
 881     bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared);
 882
 883     /*
 884      * For backward compatibility, manually share the write
 885      * and resize permission
 886      */
 887     *nshared |= (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 888     /*
 889      * Since we are not fully a format driver, don't always request
 890      * the read/resize permission but only when explicitly
 891      * requested
 892      */
 893     *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE);
 894     *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE);
 895
 896     /*
 897      * This driver doesn't modify LUKS metadata except
 898      * when updating the encryption slots.
 899      * Thus unlike a proper format driver we don't ask for
 900      * shared write/read permission. However we need it
 901      * when we are updating the keys, to ensure that only we
 902      * have access to the device.
 903      *
 904      * Encryption update will set the crypto->updating_keys
 905      * during that period and refresh permissions
 906      *
 907      */
 908     if (crypto->updating_keys) {
 909         /* need exclusive write access for header update */
 910         *nperm |= BLK_PERM_WRITE;
 911         /* unshare read and write permission */
 912         *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE);
 913     }
 914 }
 915
 916
 917 static const char *const block_crypto_strong_runtime_opts[] = {
 918     BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
 919
 920     NULL
 921 };
 922
 923 static BlockDriver bdrv_crypto_luks = {
 924     .format_name        = "luks",
 925     .instance_size      = sizeof(BlockCrypto),
 926     .bdrv_probe         = block_crypto_probe_luks,
 927     .bdrv_open          = block_crypto_open_luks,
 928     .bdrv_close         = block_crypto_close,
 929     .bdrv_child_perm    = block_crypto_child_perms,
 930     .bdrv_co_create     = block_crypto_co_create_luks,
 931     .bdrv_co_create_opts = block_crypto_co_create_opts_luks,
 932     .bdrv_co_truncate   = block_crypto_co_truncate,
 933     .create_opts        = &block_crypto_create_opts_luks,
 934     .amend_opts         = &block_crypto_amend_opts_luks,
 935
 936     .bdrv_reopen_prepare = block_crypto_reopen_prepare,
 937     .bdrv_refresh_limits = block_crypto_refresh_limits,
 938     .bdrv_co_preadv     = block_crypto_co_preadv,
 939     .bdrv_co_pwritev    = block_crypto_co_pwritev,
 940     .bdrv_getlength     = block_crypto_getlength,
 941     .bdrv_measure       = block_crypto_measure,
 942     .bdrv_get_info      = block_crypto_get_info_luks,
 943     .bdrv_get_specific_info = block_crypto_get_specific_info_luks,
 944     .bdrv_amend_options = block_crypto_amend_options_luks,
 945     .bdrv_co_amend      = block_crypto_co_amend_luks,
 946
 947     .is_format          = true,
 948
 949     .strong_runtime_opts = block_crypto_strong_runtime_opts,
 950 };
 951
 952 static void block_crypto_init(void)
 953 {
 954     bdrv_register(&bdrv_crypto_luks);
 955 }
 956
 957 block_init(block_crypto_init);