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 coroutine_fn GRAPH_UNLOCKED 103 block_crypto_create_write_func(QCryptoBlock *block, size_t offset, 104 const uint8_t *buf, size_t buflen, void *opaque, 105 Error **errp) 106 { 107 struct BlockCryptoCreateData *data = opaque; 108 ssize_t ret; 109 110 ret = blk_pwrite(data->blk, offset, buflen, buf, 0); 111 if (ret < 0) { 112 error_setg_errno(errp, -ret, "Could not write encryption header"); 113 return ret; 114 } 115 return 0; 116 } 117 118 static int coroutine_fn GRAPH_UNLOCKED 119 block_crypto_create_init_func(QCryptoBlock *block, size_t headerlen, 120 void *opaque, Error **errp) 121 { 122 struct BlockCryptoCreateData *data = opaque; 123 Error *local_error = NULL; 124 int ret; 125 126 if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) { 127 ret = -EFBIG; 128 goto error; 129 } 130 131 /* User provided size should reflect amount of space made 132 * available to the guest, so we must take account of that 133 * which will be used by the crypto header 134 */ 135 ret = blk_truncate(data->blk, data->size + headerlen, false, 136 data->prealloc, 0, &local_error); 137 138 if (ret >= 0) { 139 return 0; 140 } 141 142 error: 143 if (ret == -EFBIG) { 144 /* Replace the error message with a better one */ 145 error_free(local_error); 146 error_setg(errp, "The requested file size is too large"); 147 } else { 148 error_propagate(errp, local_error); 149 } 150 151 return ret; 152 } 153 154 155 static QemuOptsList block_crypto_runtime_opts_luks = { 156 .name = "crypto", 157 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head), 158 .desc = { 159 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 160 { /* end of list */ } 161 }, 162 }; 163 164 165 static QemuOptsList block_crypto_create_opts_luks = { 166 .name = "crypto", 167 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 168 .desc = { 169 { 170 .name = BLOCK_OPT_SIZE, 171 .type = QEMU_OPT_SIZE, 172 .help = "Virtual disk size" 173 }, 174 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 175 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""), 176 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""), 177 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""), 178 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""), 179 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""), 180 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 181 { /* end of list */ } 182 }, 183 }; 184 185 186 static QemuOptsList block_crypto_amend_opts_luks = { 187 .name = "crypto", 188 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 189 .desc = { 190 BLOCK_CRYPTO_OPT_DEF_LUKS_STATE(""), 191 BLOCK_CRYPTO_OPT_DEF_LUKS_KEYSLOT(""), 192 BLOCK_CRYPTO_OPT_DEF_LUKS_OLD_SECRET(""), 193 BLOCK_CRYPTO_OPT_DEF_LUKS_NEW_SECRET(""), 194 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 195 { /* end of list */ } 196 }, 197 }; 198 199 QCryptoBlockOpenOptions * 200 block_crypto_open_opts_init(QDict *opts, Error **errp) 201 { 202 Visitor *v; 203 QCryptoBlockOpenOptions *ret; 204 205 v = qobject_input_visitor_new_flat_confused(opts, errp); 206 if (!v) { 207 return NULL; 208 } 209 210 visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp); 211 212 visit_free(v); 213 return ret; 214 } 215 216 217 QCryptoBlockCreateOptions * 218 block_crypto_create_opts_init(QDict *opts, Error **errp) 219 { 220 Visitor *v; 221 QCryptoBlockCreateOptions *ret; 222 223 v = qobject_input_visitor_new_flat_confused(opts, errp); 224 if (!v) { 225 return NULL; 226 } 227 228 visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp); 229 230 visit_free(v); 231 return ret; 232 } 233 234 QCryptoBlockAmendOptions * 235 block_crypto_amend_opts_init(QDict *opts, Error **errp) 236 { 237 Visitor *v; 238 QCryptoBlockAmendOptions *ret; 239 240 v = qobject_input_visitor_new_flat_confused(opts, errp); 241 if (!v) { 242 return NULL; 243 } 244 245 visit_type_QCryptoBlockAmendOptions(v, NULL, &ret, errp); 246 247 visit_free(v); 248 return ret; 249 } 250 251 252 static int block_crypto_open_generic(QCryptoBlockFormat format, 253 QemuOptsList *opts_spec, 254 BlockDriverState *bs, 255 QDict *options, 256 int flags, 257 Error **errp) 258 { 259 BlockCrypto *crypto = bs->opaque; 260 QemuOpts *opts = NULL; 261 int ret; 262 QCryptoBlockOpenOptions *open_opts = NULL; 263 unsigned int cflags = 0; 264 QDict *cryptoopts = NULL; 265 266 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 267 if (ret < 0) { 268 return ret; 269 } 270 271 bs->supported_write_flags = BDRV_REQ_FUA & 272 bs->file->bs->supported_write_flags; 273 274 opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); 275 if (!qemu_opts_absorb_qdict(opts, options, errp)) { 276 ret = -EINVAL; 277 goto cleanup; 278 } 279 280 cryptoopts = qemu_opts_to_qdict(opts, NULL); 281 qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format)); 282 283 open_opts = block_crypto_open_opts_init(cryptoopts, errp); 284 if (!open_opts) { 285 ret = -EINVAL; 286 goto cleanup; 287 } 288 289 if (flags & BDRV_O_NO_IO) { 290 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 291 } 292 crypto->block = qcrypto_block_open(open_opts, NULL, 293 block_crypto_read_func, 294 bs, 295 cflags, 296 1, 297 errp); 298 299 if (!crypto->block) { 300 ret = -EIO; 301 goto cleanup; 302 } 303 304 bs->encrypted = true; 305 306 ret = 0; 307 cleanup: 308 qobject_unref(cryptoopts); 309 qapi_free_QCryptoBlockOpenOptions(open_opts); 310 return ret; 311 } 312 313 314 static int coroutine_fn GRAPH_UNLOCKED 315 block_crypto_co_create_generic(BlockDriverState *bs, int64_t size, 316 QCryptoBlockCreateOptions *opts, 317 PreallocMode prealloc, Error **errp) 318 { 319 int ret; 320 BlockBackend *blk; 321 QCryptoBlock *crypto = NULL; 322 struct BlockCryptoCreateData data; 323 324 blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL, 325 errp); 326 if (!blk) { 327 ret = -EPERM; 328 goto cleanup; 329 } 330 331 if (prealloc == PREALLOC_MODE_METADATA) { 332 prealloc = PREALLOC_MODE_OFF; 333 } 334 335 data = (struct BlockCryptoCreateData) { 336 .blk = blk, 337 .size = size, 338 .prealloc = prealloc, 339 }; 340 341 crypto = qcrypto_block_create(opts, NULL, 342 block_crypto_create_init_func, 343 block_crypto_create_write_func, 344 &data, 345 errp); 346 347 if (!crypto) { 348 ret = -EIO; 349 goto cleanup; 350 } 351 352 ret = 0; 353 cleanup: 354 qcrypto_block_free(crypto); 355 blk_co_unref(blk); 356 return ret; 357 } 358 359 static int coroutine_fn GRAPH_RDLOCK 360 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, bool exact, 361 PreallocMode prealloc, BdrvRequestFlags flags, 362 Error **errp) 363 { 364 BlockCrypto *crypto = bs->opaque; 365 uint64_t payload_offset = 366 qcrypto_block_get_payload_offset(crypto->block); 367 368 if (payload_offset > INT64_MAX - offset) { 369 error_setg(errp, "The requested file size is too large"); 370 return -EFBIG; 371 } 372 373 offset += payload_offset; 374 375 return bdrv_co_truncate(bs->file, offset, exact, prealloc, 0, errp); 376 } 377 378 static void block_crypto_close(BlockDriverState *bs) 379 { 380 BlockCrypto *crypto = bs->opaque; 381 qcrypto_block_free(crypto->block); 382 } 383 384 static int block_crypto_reopen_prepare(BDRVReopenState *state, 385 BlockReopenQueue *queue, Error **errp) 386 { 387 /* nothing needs checking */ 388 return 0; 389 } 390 391 /* 392 * 1 MB bounce buffer gives good performance / memory tradeoff 393 * when using cache=none|directsync. 394 */ 395 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024) 396 397 static int coroutine_fn GRAPH_RDLOCK 398 block_crypto_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 399 QEMUIOVector *qiov, BdrvRequestFlags flags) 400 { 401 BlockCrypto *crypto = bs->opaque; 402 uint64_t cur_bytes; /* number of bytes in current iteration */ 403 uint64_t bytes_done = 0; 404 uint8_t *cipher_data = NULL; 405 QEMUIOVector hd_qiov; 406 int ret = 0; 407 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 408 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 409 410 assert(payload_offset < INT64_MAX); 411 assert(QEMU_IS_ALIGNED(offset, sector_size)); 412 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 413 414 qemu_iovec_init(&hd_qiov, qiov->niov); 415 416 /* Bounce buffer because we don't wish to expose cipher text 417 * in qiov which points to guest memory. 418 */ 419 cipher_data = 420 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 421 qiov->size)); 422 if (cipher_data == NULL) { 423 ret = -ENOMEM; 424 goto cleanup; 425 } 426 427 while (bytes) { 428 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 429 430 qemu_iovec_reset(&hd_qiov); 431 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 432 433 ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done, 434 cur_bytes, &hd_qiov, 0); 435 if (ret < 0) { 436 goto cleanup; 437 } 438 439 if (qcrypto_block_decrypt(crypto->block, offset + bytes_done, 440 cipher_data, cur_bytes, NULL) < 0) { 441 ret = -EIO; 442 goto cleanup; 443 } 444 445 qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes); 446 447 bytes -= cur_bytes; 448 bytes_done += cur_bytes; 449 } 450 451 cleanup: 452 qemu_iovec_destroy(&hd_qiov); 453 qemu_vfree(cipher_data); 454 455 return ret; 456 } 457 458 459 static int coroutine_fn GRAPH_RDLOCK 460 block_crypto_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 461 QEMUIOVector *qiov, BdrvRequestFlags flags) 462 { 463 BlockCrypto *crypto = bs->opaque; 464 uint64_t cur_bytes; /* number of bytes in current iteration */ 465 uint64_t bytes_done = 0; 466 uint8_t *cipher_data = NULL; 467 QEMUIOVector hd_qiov; 468 int ret = 0; 469 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 470 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 471 472 flags &= ~BDRV_REQ_REGISTERED_BUF; 473 474 assert(payload_offset < INT64_MAX); 475 assert(QEMU_IS_ALIGNED(offset, sector_size)); 476 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 477 478 qemu_iovec_init(&hd_qiov, qiov->niov); 479 480 /* Bounce buffer because we're not permitted to touch 481 * contents of qiov - it points to guest memory. 482 */ 483 cipher_data = 484 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 485 qiov->size)); 486 if (cipher_data == NULL) { 487 ret = -ENOMEM; 488 goto cleanup; 489 } 490 491 while (bytes) { 492 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 493 494 qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes); 495 496 if (qcrypto_block_encrypt(crypto->block, offset + bytes_done, 497 cipher_data, cur_bytes, NULL) < 0) { 498 ret = -EIO; 499 goto cleanup; 500 } 501 502 qemu_iovec_reset(&hd_qiov); 503 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 504 505 ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done, 506 cur_bytes, &hd_qiov, flags); 507 if (ret < 0) { 508 goto cleanup; 509 } 510 511 bytes -= cur_bytes; 512 bytes_done += cur_bytes; 513 } 514 515 cleanup: 516 qemu_iovec_destroy(&hd_qiov); 517 qemu_vfree(cipher_data); 518 519 return ret; 520 } 521 522 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp) 523 { 524 BlockCrypto *crypto = bs->opaque; 525 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 526 bs->bl.request_alignment = sector_size; /* No sub-sector I/O */ 527 } 528 529 530 static int64_t coroutine_fn GRAPH_RDLOCK 531 block_crypto_co_getlength(BlockDriverState *bs) 532 { 533 BlockCrypto *crypto = bs->opaque; 534 int64_t len = bdrv_co_getlength(bs->file->bs); 535 536 uint64_t offset = qcrypto_block_get_payload_offset(crypto->block); 537 assert(offset < INT64_MAX); 538 539 if (offset > len) { 540 return -EIO; 541 } 542 543 len -= offset; 544 545 return len; 546 } 547 548 549 static BlockMeasureInfo *block_crypto_measure(QemuOpts *opts, 550 BlockDriverState *in_bs, 551 Error **errp) 552 { 553 g_autoptr(QCryptoBlockCreateOptions) create_opts = NULL; 554 Error *local_err = NULL; 555 BlockMeasureInfo *info; 556 uint64_t size; 557 size_t luks_payload_size; 558 QDict *cryptoopts; 559 560 /* 561 * Preallocation mode doesn't affect size requirements but we must consume 562 * the option. 563 */ 564 g_free(qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC)); 565 566 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 567 568 if (in_bs) { 569 int64_t ssize = bdrv_getlength(in_bs); 570 571 if (ssize < 0) { 572 error_setg_errno(&local_err, -ssize, 573 "Unable to get image virtual_size"); 574 goto err; 575 } 576 577 size = ssize; 578 } 579 580 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 581 &block_crypto_create_opts_luks, true); 582 qdict_put_str(cryptoopts, "format", "luks"); 583 create_opts = block_crypto_create_opts_init(cryptoopts, &local_err); 584 qobject_unref(cryptoopts); 585 if (!create_opts) { 586 goto err; 587 } 588 589 if (!qcrypto_block_calculate_payload_offset(create_opts, NULL, 590 &luks_payload_size, 591 &local_err)) { 592 goto err; 593 } 594 595 /* 596 * Unallocated blocks are still encrypted so allocation status makes no 597 * difference to the file size. 598 */ 599 info = g_new0(BlockMeasureInfo, 1); 600 info->fully_allocated = luks_payload_size + size; 601 info->required = luks_payload_size + size; 602 return info; 603 604 err: 605 error_propagate(errp, local_err); 606 return NULL; 607 } 608 609 610 static int block_crypto_probe_luks(const uint8_t *buf, 611 int buf_size, 612 const char *filename) { 613 return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 614 buf, buf_size, filename); 615 } 616 617 static int block_crypto_open_luks(BlockDriverState *bs, 618 QDict *options, 619 int flags, 620 Error **errp) 621 { 622 return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 623 &block_crypto_runtime_opts_luks, 624 bs, options, flags, errp); 625 } 626 627 static int coroutine_fn GRAPH_UNLOCKED 628 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp) 629 { 630 BlockdevCreateOptionsLUKS *luks_opts; 631 BlockDriverState *bs = NULL; 632 QCryptoBlockCreateOptions create_opts; 633 PreallocMode preallocation = PREALLOC_MODE_OFF; 634 int ret; 635 636 assert(create_options->driver == BLOCKDEV_DRIVER_LUKS); 637 luks_opts = &create_options->u.luks; 638 639 bs = bdrv_co_open_blockdev_ref(luks_opts->file, errp); 640 if (bs == NULL) { 641 return -EIO; 642 } 643 644 create_opts = (QCryptoBlockCreateOptions) { 645 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 646 .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts), 647 }; 648 649 if (luks_opts->has_preallocation) { 650 preallocation = luks_opts->preallocation; 651 } 652 653 ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts, 654 preallocation, errp); 655 if (ret < 0) { 656 goto fail; 657 } 658 659 ret = 0; 660 fail: 661 bdrv_co_unref(bs); 662 return ret; 663 } 664 665 static int coroutine_fn GRAPH_UNLOCKED 666 block_crypto_co_create_opts_luks(BlockDriver *drv, const char *filename, 667 QemuOpts *opts, Error **errp) 668 { 669 QCryptoBlockCreateOptions *create_opts = NULL; 670 BlockDriverState *bs = NULL; 671 QDict *cryptoopts; 672 PreallocMode prealloc; 673 char *buf = NULL; 674 int64_t size; 675 int ret; 676 Error *local_err = NULL; 677 678 /* Parse options */ 679 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 680 681 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 682 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, 683 PREALLOC_MODE_OFF, &local_err); 684 g_free(buf); 685 if (local_err) { 686 error_propagate(errp, local_err); 687 return -EINVAL; 688 } 689 690 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 691 &block_crypto_create_opts_luks, 692 true); 693 694 qdict_put_str(cryptoopts, "format", "luks"); 695 create_opts = block_crypto_create_opts_init(cryptoopts, errp); 696 if (!create_opts) { 697 ret = -EINVAL; 698 goto fail; 699 } 700 701 /* Create protocol layer */ 702 ret = bdrv_co_create_file(filename, opts, errp); 703 if (ret < 0) { 704 goto fail; 705 } 706 707 bs = bdrv_co_open(filename, NULL, NULL, 708 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 709 if (!bs) { 710 ret = -EINVAL; 711 goto fail; 712 } 713 714 /* Create format layer */ 715 ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp); 716 if (ret < 0) { 717 goto fail; 718 } 719 720 ret = 0; 721 fail: 722 /* 723 * If an error occurred, delete 'filename'. Even if the file existed 724 * beforehand, it has been truncated and corrupted in the process. 725 */ 726 if (ret) { 727 bdrv_graph_co_rdlock(); 728 bdrv_co_delete_file_noerr(bs); 729 bdrv_graph_co_rdunlock(); 730 } 731 732 bdrv_co_unref(bs); 733 qapi_free_QCryptoBlockCreateOptions(create_opts); 734 qobject_unref(cryptoopts); 735 return ret; 736 } 737 738 static int coroutine_fn GRAPH_RDLOCK 739 block_crypto_co_get_info_luks(BlockDriverState *bs, BlockDriverInfo *bdi) 740 { 741 BlockDriverInfo subbdi; 742 int ret; 743 744 ret = bdrv_co_get_info(bs->file->bs, &subbdi); 745 if (ret != 0) { 746 return ret; 747 } 748 749 bdi->cluster_size = subbdi.cluster_size; 750 751 return 0; 752 } 753 754 static ImageInfoSpecific * 755 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) 756 { 757 BlockCrypto *crypto = bs->opaque; 758 ImageInfoSpecific *spec_info; 759 QCryptoBlockInfo *info; 760 761 info = qcrypto_block_get_info(crypto->block, errp); 762 if (!info) { 763 return NULL; 764 } 765 assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS); 766 767 spec_info = g_new(ImageInfoSpecific, 1); 768 spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; 769 spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); 770 *spec_info->u.luks.data = info->u.luks; 771 772 /* Blank out pointers we've just stolen to avoid double free */ 773 memset(&info->u.luks, 0, sizeof(info->u.luks)); 774 775 qapi_free_QCryptoBlockInfo(info); 776 777 return spec_info; 778 } 779 780 static int 781 block_crypto_amend_prepare(BlockDriverState *bs, Error **errp) 782 { 783 BlockCrypto *crypto = bs->opaque; 784 int ret; 785 786 /* apply for exclusive read/write permissions to the underlying file */ 787 crypto->updating_keys = true; 788 ret = bdrv_child_refresh_perms(bs, bs->file, errp); 789 if (ret < 0) { 790 /* Well, in this case we will not be updating any keys */ 791 crypto->updating_keys = false; 792 } 793 return ret; 794 } 795 796 static void 797 block_crypto_amend_cleanup(BlockDriverState *bs) 798 { 799 BlockCrypto *crypto = bs->opaque; 800 Error *errp = NULL; 801 802 /* release exclusive read/write permissions to the underlying file */ 803 crypto->updating_keys = false; 804 bdrv_child_refresh_perms(bs, bs->file, &errp); 805 806 if (errp) { 807 error_report_err(errp); 808 } 809 } 810 811 static int 812 block_crypto_amend_options_generic_luks(BlockDriverState *bs, 813 QCryptoBlockAmendOptions *amend_options, 814 bool force, 815 Error **errp) 816 { 817 BlockCrypto *crypto = bs->opaque; 818 819 assert(crypto); 820 assert(crypto->block); 821 822 return qcrypto_block_amend_options(crypto->block, 823 block_crypto_read_func, 824 block_crypto_write_func, 825 bs, 826 amend_options, 827 force, 828 errp); 829 } 830 831 static int 832 block_crypto_amend_options_luks(BlockDriverState *bs, 833 QemuOpts *opts, 834 BlockDriverAmendStatusCB *status_cb, 835 void *cb_opaque, 836 bool force, 837 Error **errp) 838 { 839 BlockCrypto *crypto = bs->opaque; 840 QDict *cryptoopts = NULL; 841 QCryptoBlockAmendOptions *amend_options = NULL; 842 int ret = -EINVAL; 843 844 assert(crypto); 845 assert(crypto->block); 846 847 cryptoopts = qemu_opts_to_qdict(opts, NULL); 848 qdict_put_str(cryptoopts, "format", "luks"); 849 amend_options = block_crypto_amend_opts_init(cryptoopts, errp); 850 qobject_unref(cryptoopts); 851 if (!amend_options) { 852 goto cleanup; 853 } 854 855 ret = block_crypto_amend_prepare(bs, errp); 856 if (ret) { 857 goto perm_cleanup; 858 } 859 ret = block_crypto_amend_options_generic_luks(bs, amend_options, 860 force, errp); 861 862 perm_cleanup: 863 block_crypto_amend_cleanup(bs); 864 cleanup: 865 qapi_free_QCryptoBlockAmendOptions(amend_options); 866 return ret; 867 } 868 869 static int 870 coroutine_fn block_crypto_co_amend_luks(BlockDriverState *bs, 871 BlockdevAmendOptions *opts, 872 bool force, 873 Error **errp) 874 { 875 QCryptoBlockAmendOptions amend_opts; 876 877 amend_opts = (QCryptoBlockAmendOptions) { 878 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 879 .u.luks = *qapi_BlockdevAmendOptionsLUKS_base(&opts->u.luks), 880 }; 881 return block_crypto_amend_options_generic_luks(bs, &amend_opts, 882 force, errp); 883 } 884 885 static void 886 block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c, 887 const BdrvChildRole role, 888 BlockReopenQueue *reopen_queue, 889 uint64_t perm, uint64_t shared, 890 uint64_t *nperm, uint64_t *nshared) 891 { 892 893 BlockCrypto *crypto = bs->opaque; 894 895 bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared); 896 897 /* 898 * For backward compatibility, manually share the write 899 * and resize permission 900 */ 901 *nshared |= shared & (BLK_PERM_WRITE | BLK_PERM_RESIZE); 902 /* 903 * Since we are not fully a format driver, don't always request 904 * the read/resize permission but only when explicitly 905 * requested 906 */ 907 *nperm &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); 908 *nperm |= perm & (BLK_PERM_WRITE | BLK_PERM_RESIZE); 909 910 /* 911 * This driver doesn't modify LUKS metadata except 912 * when updating the encryption slots. 913 * Thus unlike a proper format driver we don't ask for 914 * shared write/read permission. However we need it 915 * when we are updating the keys, to ensure that only we 916 * have access to the device. 917 * 918 * Encryption update will set the crypto->updating_keys 919 * during that period and refresh permissions 920 * 921 */ 922 if (crypto->updating_keys) { 923 /* need exclusive write access for header update */ 924 *nperm |= BLK_PERM_WRITE; 925 /* unshare read and write permission */ 926 *nshared &= ~(BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE); 927 } 928 } 929 930 931 static const char *const block_crypto_strong_runtime_opts[] = { 932 BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, 933 934 NULL 935 }; 936 937 static BlockDriver bdrv_crypto_luks = { 938 .format_name = "luks", 939 .instance_size = sizeof(BlockCrypto), 940 .bdrv_probe = block_crypto_probe_luks, 941 .bdrv_open = block_crypto_open_luks, 942 .bdrv_close = block_crypto_close, 943 .bdrv_child_perm = block_crypto_child_perms, 944 .bdrv_co_create = block_crypto_co_create_luks, 945 .bdrv_co_create_opts = block_crypto_co_create_opts_luks, 946 .bdrv_co_truncate = block_crypto_co_truncate, 947 .create_opts = &block_crypto_create_opts_luks, 948 .amend_opts = &block_crypto_amend_opts_luks, 949 950 .bdrv_reopen_prepare = block_crypto_reopen_prepare, 951 .bdrv_refresh_limits = block_crypto_refresh_limits, 952 .bdrv_co_preadv = block_crypto_co_preadv, 953 .bdrv_co_pwritev = block_crypto_co_pwritev, 954 .bdrv_co_getlength = block_crypto_co_getlength, 955 .bdrv_measure = block_crypto_measure, 956 .bdrv_co_get_info = block_crypto_co_get_info_luks, 957 .bdrv_get_specific_info = block_crypto_get_specific_info_luks, 958 .bdrv_amend_options = block_crypto_amend_options_luks, 959 .bdrv_co_amend = block_crypto_co_amend_luks, 960 .bdrv_amend_pre_run = block_crypto_amend_prepare, 961 .bdrv_amend_clean = block_crypto_amend_cleanup, 962 963 .is_format = true, 964 965 .strong_runtime_opts = block_crypto_strong_runtime_opts, 966 }; 967 968 static void block_crypto_init(void) 969 { 970 bdrv_register(&bdrv_crypto_luks); 971 } 972 973 block_init(block_crypto_init); 974