1 /* 2 * QEMU block full disk encryption 3 * 4 * Copyright (c) 2015-2016 Red Hat, Inc. 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 * 19 */ 20 21 #include "qemu/osdep.h" 22 23 #include "block/block_int.h" 24 #include "block/qdict.h" 25 #include "sysemu/block-backend.h" 26 #include "crypto/block.h" 27 #include "qapi/opts-visitor.h" 28 #include "qapi/qapi-visit-crypto.h" 29 #include "qapi/qobject-input-visitor.h" 30 #include "qapi/error.h" 31 #include "qemu/module.h" 32 #include "qemu/option.h" 33 #include "qemu/cutils.h" 34 #include "crypto.h" 35 36 typedef struct BlockCrypto BlockCrypto; 37 38 struct BlockCrypto { 39 QCryptoBlock *block; 40 bool updating_keys; 41 }; 42 43 44 static int block_crypto_probe_generic(QCryptoBlockFormat format, 45 const uint8_t *buf, 46 int buf_size, 47 const char *filename) 48 { 49 if (qcrypto_block_has_format(format, buf, buf_size)) { 50 return 100; 51 } else { 52 return 0; 53 } 54 } 55 56 57 static ssize_t block_crypto_read_func(QCryptoBlock *block, 58 size_t offset, 59 uint8_t *buf, 60 size_t buflen, 61 void *opaque, 62 Error **errp) 63 { 64 BlockDriverState *bs = opaque; 65 ssize_t ret; 66 67 ret = bdrv_pread(bs->file, offset, buf, buflen); 68 if (ret < 0) { 69 error_setg_errno(errp, -ret, "Could not read encryption header"); 70 return ret; 71 } 72 return ret; 73 } 74 75 static ssize_t block_crypto_write_func(QCryptoBlock *block, 76 size_t offset, 77 const uint8_t *buf, 78 size_t buflen, 79 void *opaque, 80 Error **errp) 81 { 82 BlockDriverState *bs = opaque; 83 ssize_t ret; 84 85 ret = bdrv_pwrite(bs->file, offset, buf, buflen); 86 if (ret < 0) { 87 error_setg_errno(errp, -ret, "Could not write encryption header"); 88 return ret; 89 } 90 return ret; 91 } 92 93 94 struct BlockCryptoCreateData { 95 BlockBackend *blk; 96 uint64_t size; 97 PreallocMode prealloc; 98 }; 99 100 101 static ssize_t block_crypto_create_write_func(QCryptoBlock *block, 102 size_t offset, 103 const uint8_t *buf, 104 size_t buflen, 105 void *opaque, 106 Error **errp) 107 { 108 struct BlockCryptoCreateData *data = opaque; 109 ssize_t ret; 110 111 ret = blk_pwrite(data->blk, offset, buf, buflen, 0); 112 if (ret < 0) { 113 error_setg_errno(errp, -ret, "Could not write encryption header"); 114 return ret; 115 } 116 return ret; 117 } 118 119 static ssize_t block_crypto_create_init_func(QCryptoBlock *block, 120 size_t headerlen, 121 void *opaque, 122 Error **errp) 123 { 124 struct BlockCryptoCreateData *data = opaque; 125 Error *local_error = NULL; 126 int ret; 127 128 if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) { 129 ret = -EFBIG; 130 goto error; 131 } 132 133 /* User provided size should reflect amount of space made 134 * available to the guest, so we must take account of that 135 * which will be used by the crypto header 136 */ 137 ret = blk_truncate(data->blk, data->size + headerlen, false, 138 data->prealloc, 0, &local_error); 139 140 if (ret >= 0) { 141 return ret; 142 } 143 144 error: 145 if (ret == -EFBIG) { 146 /* Replace the error message with a better one */ 147 error_free(local_error); 148 error_setg(errp, "The requested file size is too large"); 149 } else { 150 error_propagate(errp, local_error); 151 } 152 153 return ret; 154 } 155 156 157 static QemuOptsList block_crypto_runtime_opts_luks = { 158 .name = "crypto", 159 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head), 160 .desc = { 161 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 162 { /* end of list */ } 163 }, 164 }; 165 166 167 static QemuOptsList block_crypto_create_opts_luks = { 168 .name = "crypto", 169 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 170 .desc = { 171 { 172 .name = BLOCK_OPT_SIZE, 173 .type = QEMU_OPT_SIZE, 174 .help = "Virtual disk size" 175 }, 176 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 177 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""), 178 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""), 179 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""), 180 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""), 181 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""), 182 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 183 { /* end of list */ } 184 }, 185 }; 186 187 188 static QemuOptsList block_crypto_amend_opts_luks = { 189 .name = "crypto", 190 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 191 .desc = { 192 BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(""), 193 BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(""), 194 BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(""), 195 BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(""), 196 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 197 { /* end of list */ } 198 }, 199 }; 200 201 QCryptoBlockOpenOptions * 202 block_crypto_open_opts_init(QDict *opts, Error **errp) 203 { 204 Visitor *v; 205 QCryptoBlockOpenOptions *ret; 206 207 v = qobject_input_visitor_new_flat_confused(opts, errp); 208 if (!v) { 209 return NULL; 210 } 211 212 visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp); 213 214 visit_free(v); 215 return ret; 216 } 217 218 219 QCryptoBlockCreateOptions * 220 block_crypto_create_opts_init(QDict *opts, Error **errp) 221 { 222 Visitor *v; 223 QCryptoBlockCreateOptions *ret; 224 225 v = qobject_input_visitor_new_flat_confused(opts, errp); 226 if (!v) { 227 return NULL; 228 } 229 230 visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp); 231 232 visit_free(v); 233 return ret; 234 } 235 236 QCryptoBlockAmendOptions * 237 block_crypto_amend_opts_init(QDict *opts, Error **errp) 238 { 239 Visitor *v; 240 QCryptoBlockAmendOptions *ret; 241 242 v = qobject_input_visitor_new_flat_confused(opts, errp); 243 if (!v) { 244 return NULL; 245 } 246 247 visit_type_QCryptoBlockAmendOptions(v, NULL, &ret, errp); 248 249 visit_free(v); 250 return ret; 251 } 252 253 254 static int block_crypto_open_generic(QCryptoBlockFormat format, 255 QemuOptsList *opts_spec, 256 BlockDriverState *bs, 257 QDict *options, 258 int flags, 259 Error **errp) 260 { 261 BlockCrypto *crypto = bs->opaque; 262 QemuOpts *opts = NULL; 263 Error *local_err = NULL; 264 int ret = -EINVAL; 265 QCryptoBlockOpenOptions *open_opts = NULL; 266 unsigned int cflags = 0; 267 QDict *cryptoopts = NULL; 268 269 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds, 270 BDRV_CHILD_IMAGE, false, errp); 271 if (!bs->file) { 272 return -EINVAL; 273 } 274 275 bs->supported_write_flags = BDRV_REQ_FUA & 276 bs->file->bs->supported_write_flags; 277 278 opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); 279 if (!qemu_opts_absorb_qdict(opts, options, &local_err)) { 280 error_propagate(errp, local_err); 281 goto cleanup; 282 } 283 284 cryptoopts = qemu_opts_to_qdict(opts, NULL); 285 qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format)); 286 287 open_opts = block_crypto_open_opts_init(cryptoopts, errp); 288 if (!open_opts) { 289 goto cleanup; 290 } 291 292 if (flags & BDRV_O_NO_IO) { 293 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 294 } 295 crypto->block = qcrypto_block_open(open_opts, NULL, 296 block_crypto_read_func, 297 bs, 298 cflags, 299 1, 300 errp); 301 302 if (!crypto->block) { 303 ret = -EIO; 304 goto cleanup; 305 } 306 307 bs->encrypted = true; 308 309 ret = 0; 310 cleanup: 311 qobject_unref(cryptoopts); 312 qapi_free_QCryptoBlockOpenOptions(open_opts); 313 return ret; 314 } 315 316 317 static int block_crypto_co_create_generic(BlockDriverState *bs, 318 int64_t size, 319 QCryptoBlockCreateOptions *opts, 320 PreallocMode prealloc, 321 Error **errp) 322 { 323 int ret; 324 BlockBackend *blk; 325 QCryptoBlock *crypto = NULL; 326 struct BlockCryptoCreateData data; 327 328 blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL, 329 errp); 330 if (!blk) { 331 ret = -EPERM; 332 goto cleanup; 333 } 334 335 if (prealloc == PREALLOC_MODE_METADATA) { 336 prealloc = PREALLOC_MODE_OFF; 337 } 338 339 data = (struct BlockCryptoCreateData) { 340 .blk = blk, 341 .size = size, 342 .prealloc = prealloc, 343 }; 344 345 crypto = qcrypto_block_create(opts, NULL, 346 block_crypto_create_init_func, 347 block_crypto_create_write_func, 348 &data, 349 errp); 350 351 if (!crypto) { 352 ret = -EIO; 353 goto cleanup; 354 } 355 356 ret = 0; 357 cleanup: 358 qcrypto_block_free(crypto); 359 blk_unref(blk); 360 return ret; 361 } 362 363 static int coroutine_fn 364 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact, 365 PreallocMode prealloc, BdrvRequestFlags flags, 366 Error **errp) 367 { 368 BlockCrypto *crypto = bs->opaque; 369 uint64_t payload_offset = 370 qcrypto_block_get_payload_offset(crypto->block); 371 372 if (payload_offset > INT64_MAX - offset) { 373 error_setg(errp, "The requested file size is too large"); 374 return -EFBIG; 375 } 376 377 offset += payload_offset; 378 379 return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp); 380 } 381 382 static void block_crypto_close(BlockDriverState *bs) 383 { 384 BlockCrypto *crypto = bs->opaque; 385 qcrypto_block_free(crypto->block); 386 } 387 388 static int block_crypto_reopen_prepare(BDRVReopenState *state, 389 BlockReopenQueue *queue, Error **errp) 390 { 391 /* nothing needs checking */ 392 return 0; 393 } 394 395 /* 396 * 1 MB bounce buffer gives good performance / memory tradeoff 397 * when using cache=none|directsync. 398 */ 399 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024) 400 401 static coroutine_fn int 402 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 403 QEMUIOVector *qiov, int flags) 404 { 405 BlockCrypto *crypto = bs->opaque; 406 uint64_t cur_bytes; /* number of bytes in current iteration */ 407 uint64_t bytes_done = 0; 408 uint8_t *cipher_data = NULL; 409 QEMUIOVector hd_qiov; 410 int ret = 0; 411 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 412 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 413 414 assert(!flags); 415 assert(payload_offset < INT64_MAX); 416 assert(QEMU_IS_ALIGNED(offset, sector_size)); 417 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 418 419 qemu_iovec_init(&hd_qiov, qiov->niov); 420 421 /* Bounce buffer because we don't wish to expose cipher text 422 * in qiov which points to guest memory. 423 */ 424 cipher_data = 425 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 426 qiov->size)); 427 if (cipher_data == NULL) { 428 ret = -ENOMEM; 429 goto cleanup; 430 } 431 432 while (bytes) { 433 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 434 435 qemu_iovec_reset(&hd_qiov); 436 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 437 438 ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done, 439 cur_bytes, &hd_qiov, 0); 440 if (ret < 0) { 441 goto cleanup; 442 } 443 444 if (qcrypto_block_decrypt(crypto->block, offset + bytes_done, 445 cipher_data, cur_bytes, NULL) < 0) { 446 ret = -EIO; 447 goto cleanup; 448 } 449 450 qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes); 451 452 bytes -= cur_bytes; 453 bytes_done += cur_bytes; 454 } 455 456 cleanup: 457 qemu_iovec_destroy(&hd_qiov); 458 qemu_vfree(cipher_data); 459 460 return ret; 461 } 462 463 464 static coroutine_fn int 465 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 466 QEMUIOVector *qiov, int flags) 467 { 468 BlockCrypto *crypto = bs->opaque; 469 uint64_t cur_bytes; /* number of bytes in current iteration */ 470 uint64_t bytes_done = 0; 471 uint8_t *cipher_data = NULL; 472 QEMUIOVector hd_qiov; 473 int ret = 0; 474 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 475 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 476 477 assert(!(flags & ~BDRV_REQ_FUA)); 478 assert(payload_offset < INT64_MAX); 479 assert(QEMU_IS_ALIGNED(offset, sector_size)); 480 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 481 482 qemu_iovec_init(&hd_qiov, qiov->niov); 483 484 /* Bounce buffer because we're not permitted to touch 485 * contents of qiov - it points to guest memory. 486 */ 487 cipher_data = 488 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 489 qiov->size)); 490 if (cipher_data == NULL) { 491 ret = -ENOMEM; 492 goto cleanup; 493 } 494 495 while (bytes) { 496 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 497 498 qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes); 499 500 if (qcrypto_block_encrypt(crypto->block, offset + bytes_done, 501 cipher_data, cur_bytes, NULL) < 0) { 502 ret = -EIO; 503 goto cleanup; 504 } 505 506 qemu_iovec_reset(&hd_qiov); 507 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 508 509 ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done, 510 cur_bytes, &hd_qiov, flags); 511 if (ret < 0) { 512 goto cleanup; 513 } 514 515 bytes -= cur_bytes; 516 bytes_done += cur_bytes; 517 } 518 519 cleanup: 520 qemu_iovec_destroy(&hd_qiov); 521 qemu_vfree(cipher_data); 522 523 return ret; 524 } 525 526 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp) 527 { 528 BlockCrypto *crypto = bs->opaque; 529 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 530 bs->bl.request_alignment = sector_size; /* No sub-sector I/O */ 531 } 532 533 534 static int64_t block_crypto_getlength(BlockDriverState *bs) 535 { 536 BlockCrypto *crypto = bs->opaque; 537 int64_t len = bdrv_getlength(bs->file->bs); 538 539 uint64_t offset = qcrypto_block_get_payload_offset(crypto->block); 540 assert(offset < INT64_MAX); 541 542 if (offset > len) { 543 return -EIO; 544 } 545 546 len -= offset; 547 548 return len; 549 } 550 551 552 static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts, 553 BlockDriverState *in_bs, 554 Error **errp) 555 { 556 g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL; 557 Error *local_err = NULL; 558 BlockMeasureInfo *info; 559 uint64_t size; 560 size_t luks_payload_size; 561 QDict *cryptoopts; 562 563 /* 564 * Preallocation mode doesn't affect size requirements but we must consume 565 * the option. 566 */ 567 g_free(qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC)); 568 569 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 570 571 if (in_bs) { 572 int64_t ssize = bdrv_getlength(in_bs); 573 574 if (ssize < 0) { 575 error_setg_errno(&local_err, -ssize, 576 "Unable to get image virtual_size"); 577 goto err; 578 } 579 580 size = ssize; 581 } 582 583 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 584 &block_crypto_create_opts_luks, true); 585 qdict_put_str(cryptoopts, "format", "luks"); 586 create_opts = block_crypto_create_opts_init(cryptoopts, &local_err); 587 qobject_unref(cryptoopts); 588 if (!create_opts) { 589 goto err; 590 } 591 592 if (!qcrypto_block_calculate_payload_offset(create_opts, NULL, 593 &luks_payload_size, 594 &local_err)) { 595 goto err; 596 } 597 598 /* 599 * Unallocated blocks are still encrypted so allocation status makes no 600 * difference to the file size. 601 */ 602 info = g_new0(BlockMeasureInfo, 1); 603 info->fully_allocated = luks_payload_size + size; 604 info->required = luks_payload_size + size; 605 return info; 606 607 err: 608 error_propagate(errp, local_err); 609 return NULL; 610 } 611 612 613 static int block_crypto_probe_luks(const uint8_t *buf, 614 int buf_size, 615 const char *filename) { 616 return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 617 buf, buf_size, filename); 618 } 619 620 static int block_crypto_open_luks(BlockDriverState *bs, 621 QDict *options, 622 int flags, 623 Error **errp) 624 { 625 return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 626 &block_crypto_runtime_opts_luks, 627 bs, options, flags, errp); 628 } 629 630 static int coroutine_fn 631 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp) 632 { 633 BlockdevCreateOptionsLUKS *luks_opts; 634 BlockDriverState *bs = NULL; 635 QCryptoBlockCreateOptions create_opts; 636 PreallocMode preallocation = PREALLOC_MODE_OFF; 637 int ret; 638 639 assert(create_options->driver == BLOCKDEV_DRIVER_LUKS); 640 luks_opts = &create_options->u.luks; 641 642 bs = bdrv_open_blockdev_ref(luks_opts->file, errp); 643 if (bs == NULL) { 644 return -EIO; 645 } 646 647 create_opts = (QCryptoBlockCreateOptions) { 648 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 649 .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts), 650 }; 651 652 if (luks_opts->has_preallocation) { 653 preallocation = luks_opts->preallocation; 654 } 655 656 ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts, 657 preallocation, errp); 658 if (ret < 0) { 659 goto fail; 660 } 661 662 ret = 0; 663 fail: 664 bdrv_unref(bs); 665 return ret; 666 } 667 668 static int coroutine_fn block_crypto_co_create_opts_luks(BlockDriver *drv, 669 const char *filename, 670 QemuOpts *opts, 671 Error **errp) 672 { 673 QCryptoBlockCreateOptions *create_opts = NULL; 674 BlockDriverState *bs = NULL; 675 QDict *cryptoopts; 676 PreallocMode prealloc; 677 char *buf = NULL; 678 int64_t size; 679 int ret; 680 Error *local_err = NULL; 681 682 /* Parse options */ 683 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 684 685 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 686 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, 687 PREALLOC_MODE_OFF, &local_err); 688 g_free(buf); 689 if (local_err) { 690 error_propagate(errp, local_err); 691 return -EINVAL; 692 } 693 694 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 695 &block_crypto_create_opts_luks, 696 true); 697 698 qdict_put_str(cryptoopts, "format", "luks"); 699 create_opts = block_crypto_create_opts_init(cryptoopts, errp); 700 if (!create_opts) { 701 ret = -EINVAL; 702 goto fail; 703 } 704 705 /* Create protocol layer */ 706 ret = bdrv_create_file(filename, opts, errp); 707 if (ret < 0) { 708 goto fail; 709 } 710 711 bs = bdrv_open(filename, NULL, NULL, 712 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 713 if (!bs) { 714 ret = -EINVAL; 715 goto fail; 716 } 717 718 /* Create format layer */ 719 ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp); 720 if (ret < 0) { 721 goto fail; 722 } 723 724 ret = 0; 725 fail: 726 /* 727 * If an error occurred, delete 'filename'. Even if the file existed 728 * beforehand, it has been truncated and corrupted in the process. 729 */ 730 if (ret && bs) { 731 Error *local_delete_err = NULL; 732 int r_del = bdrv_co_delete_file(bs, &local_delete_err); 733 /* 734 * ENOTSUP will happen if the block driver doesn't support 735 * the 'bdrv_co_delete_file' interface. This is a predictable 736 * scenario and shouldn't be reported back to the user. 737 */ 738 if ((r_del < 0) && (r_del != -ENOTSUP)) { 739 error_report_err(local_delete_err); 740 } 741 } 742 743 bdrv_unref(bs); 744 qapi_free_QCryptoBlockCreateOptions(create_opts); 745 qobject_unref(cryptoopts); 746 return ret; 747 } 748 749 static int block_crypto_get_info_luks(BlockDriverState *bs, 750 BlockDriverInfo *bdi) 751 { 752 BlockDriverInfo subbdi; 753 int ret; 754 755 ret = bdrv_get_info(bs->file->bs, &subbdi); 756 if (ret != 0) { 757 return ret; 758 } 759 760 bdi->cluster_size = subbdi.cluster_size; 761 762 return 0; 763 } 764 765 static ImageInfoSpecific * 766 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) 767 { 768 BlockCrypto *crypto = bs->opaque; 769 ImageInfoSpecific *spec_info; 770 QCryptoBlockInfo *info; 771 772 info = qcrypto_block_get_info(crypto->block, errp); 773 if (!info) { 774 return NULL; 775 } 776 assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS); 777 778 spec_info = g_new(ImageInfoSpecific, 1); 779 spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; 780 spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); 781 *spec_info->u.luks.data = info->u.luks; 782 783 /* Blank out pointers we've just stolen to avoid double free */ 784 memset(&info->u.luks, 0, sizeof(info->u.luks)); 785 786 qapi_free_QCryptoBlockInfo(info); 787 788 return spec_info; 789 } 790 791 static int 792 block_crypto_amend_options_generic_luks(BlockDriverState *bs, 793 QCryptoBlockAmendOptions *amend_options, 794 bool force, 795 Error **errp) 796 { 797 BlockCrypto *crypto = bs->opaque; 798 int ret; 799 800 assert(crypto); 801 assert(crypto->block); 802 803 /* apply for exclusive read/write permissions to the underlying file*/ 804 crypto->updating_keys = true; 805 ret = bdrv_child_refresh_perms(bs, bs->file, errp); 806 if (ret) { 807 goto cleanup; 808 } 809 810 ret = qcrypto_block_amend_options(crypto->block, 811 block_crypto_read_func, 812 block_crypto_write_func, 813 bs, 814 amend_options, 815 force, 816 errp); 817 cleanup: 818 /* release exclusive read/write permissions to the underlying file*/ 819 crypto->updating_keys = false; 820 bdrv_child_refresh_perms(bs, bs->file, errp); 821 return ret; 822 } 823 824 static int 825 block_crypto_amend_options_luks(BlockDriverState *bs, 826 QemuOpts *opts, 827 BlockDriverAmendStatusCB *status_cb, 828 void *cb_opaque, 829 bool force, 830 Error **errp) 831 { 832 BlockCrypto *crypto = bs->opaque; 833 QDict *cryptoopts = NULL; 834 QCryptoBlockAmendOptions *amend_options = NULL; 835 int ret = -EINVAL; 836 837 assert(crypto); 838 assert(crypto->block); 839 840 cryptoopts = qemu_opts_to_qdict(opts, NULL); 841 qdict_put_str(cryptoopts, "format", "luks"); 842 amend_options = block_crypto_amend_opts_init(cryptoopts, errp); 843 qobject_unref(cryptoopts); 844 if (!amend_options) { 845 goto cleanup; 846 } 847 ret = block_crypto_amend_options_generic_luks(bs, amend_options, 848 force, errp); 849 cleanup: 850 qapi_free_QCryptoBlockAmendOptions(amend_options); 851 return ret; 852 } 853 854 static int 855 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs, 856 BlockdevAmendOptions *opts, 857 bool force, 858 Error **errp) 859 { 860 QCryptoBlockAmendOptions amend_opts; 861 862 amend_opts = (QCryptoBlockAmendOptions) { 863 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 864 .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks), 865 }; 866 return block_crypto_amend_options_generic_luks(bs, &amend_opts, 867 force, errp); 868 } 869 870 static void 871 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c, 872 const BdrvChildRole role, 873 BlockReopenQueue *reopen_queue, 874 uint64_t perm, uint64_t shared, 875 uint64_t *nperm, uint64_t *nshared) 876 { 877 878 BlockCrypto *crypto = bs->opaque; 879 880 bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared); 881 882 /* 883 * For backward compatibility, manually share the write 884 * and resize permission 885 */ 886 *nshared |= (BLK_PERM_WRITE | BLK_PERM_RESIZE); 887 /* 888 * Since we are not fully a format driver, don't always request 889 * the read/resize permission but only when explicitly 890 * requested 891 */ 892 *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); 893 *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE); 894 895 /* 896 * This driver doesn't modify LUKS metadata except 897 * when updating the encryption slots. 898 * Thus unlike a proper format driver we don't ask for 899 * shared write/read permission. However we need it 900 * when we are updating the keys, to ensure that only we 901 * have access to the device. 902 * 903 * Encryption update will set the crypto->updating_keys 904 * during that period and refresh permissions 905 * 906 */ 907 if (crypto->updating_keys) { 908 /* need exclusive write access for header update */ 909 *nperm |= BLK_PERM_WRITE; 910 /* unshare read and write permission */ 911 *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE); 912 } 913 } 914 915 916 static const char *const block_crypto_strong_runtime_opts[] = { 917 BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, 918 919 NULL 920 }; 921 922 static BlockDriver bdrv_crypto_luks = { 923 .format_name = "luks", 924 .instance_size = sizeof(BlockCrypto), 925 .bdrv_probe = block_crypto_probe_luks, 926 .bdrv_open = block_crypto_open_luks, 927 .bdrv_close = block_crypto_close, 928 .bdrv_child_perm = block_crypto_child_perms, 929 .bdrv_co_create = block_crypto_co_create_luks, 930 .bdrv_co_create_opts = block_crypto_co_create_opts_luks, 931 .bdrv_co_truncate = block_crypto_co_truncate, 932 .create_opts = &block_crypto_create_opts_luks, 933 .amend_opts = &block_crypto_amend_opts_luks, 934 935 .bdrv_reopen_prepare = block_crypto_reopen_prepare, 936 .bdrv_refresh_limits = block_crypto_refresh_limits, 937 .bdrv_co_preadv = block_crypto_co_preadv, 938 .bdrv_co_pwritev = block_crypto_co_pwritev, 939 .bdrv_getlength = block_crypto_getlength, 940 .bdrv_measure = block_crypto_measure, 941 .bdrv_get_info = block_crypto_get_info_luks, 942 .bdrv_get_specific_info = block_crypto_get_specific_info_luks, 943 .bdrv_amend_options = block_crypto_amend_options_luks, 944 .bdrv_co_amend = block_crypto_co_amend_luks, 945 946 .is_format = true, 947 948 .strong_runtime_opts = block_crypto_strong_runtime_opts, 949 }; 950 951 static void block_crypto_init(void) 952 { 953 bdrv_register(&bdrv_crypto_luks); 954 } 955 956 block_init(block_crypto_init); 957