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 "sysemu/block-backend.h" 25 #include "crypto/block.h" 26 #include "qapi/opts-visitor.h" 27 #include "qapi/qapi-visit-crypto.h" 28 #include "qapi/qmp/qdict.h" 29 #include "qapi/qobject-input-visitor.h" 30 #include "qapi/error.h" 31 #include "qemu/option.h" 32 #include "block/crypto.h" 33 34 typedef struct BlockCrypto BlockCrypto; 35 36 struct BlockCrypto { 37 QCryptoBlock *block; 38 }; 39 40 41 static int block_crypto_probe_generic(QCryptoBlockFormat format, 42 const uint8_t *buf, 43 int buf_size, 44 const char *filename) 45 { 46 if (qcrypto_block_has_format(format, buf, buf_size)) { 47 return 100; 48 } else { 49 return 0; 50 } 51 } 52 53 54 static ssize_t block_crypto_read_func(QCryptoBlock *block, 55 size_t offset, 56 uint8_t *buf, 57 size_t buflen, 58 void *opaque, 59 Error **errp) 60 { 61 BlockDriverState *bs = opaque; 62 ssize_t ret; 63 64 ret = bdrv_pread(bs->file, offset, buf, buflen); 65 if (ret < 0) { 66 error_setg_errno(errp, -ret, "Could not read encryption header"); 67 return ret; 68 } 69 return ret; 70 } 71 72 73 struct BlockCryptoCreateData { 74 BlockBackend *blk; 75 uint64_t size; 76 }; 77 78 79 static ssize_t block_crypto_write_func(QCryptoBlock *block, 80 size_t offset, 81 const uint8_t *buf, 82 size_t buflen, 83 void *opaque, 84 Error **errp) 85 { 86 struct BlockCryptoCreateData *data = opaque; 87 ssize_t ret; 88 89 ret = blk_pwrite(data->blk, offset, buf, buflen, 0); 90 if (ret < 0) { 91 error_setg_errno(errp, -ret, "Could not write encryption header"); 92 return ret; 93 } 94 return ret; 95 } 96 97 98 static ssize_t block_crypto_init_func(QCryptoBlock *block, 99 size_t headerlen, 100 void *opaque, 101 Error **errp) 102 { 103 struct BlockCryptoCreateData *data = opaque; 104 105 if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) { 106 error_setg(errp, "The requested file size is too large"); 107 return -EFBIG; 108 } 109 110 /* User provided size should reflect amount of space made 111 * available to the guest, so we must take account of that 112 * which will be used by the crypto header 113 */ 114 return blk_truncate(data->blk, data->size + headerlen, PREALLOC_MODE_OFF, 115 errp); 116 } 117 118 119 static QemuOptsList block_crypto_runtime_opts_luks = { 120 .name = "crypto", 121 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head), 122 .desc = { 123 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 124 { /* end of list */ } 125 }, 126 }; 127 128 129 static QemuOptsList block_crypto_create_opts_luks = { 130 .name = "crypto", 131 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 132 .desc = { 133 { 134 .name = BLOCK_OPT_SIZE, 135 .type = QEMU_OPT_SIZE, 136 .help = "Virtual disk size" 137 }, 138 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 139 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""), 140 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""), 141 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""), 142 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""), 143 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""), 144 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 145 { /* end of list */ } 146 }, 147 }; 148 149 150 QCryptoBlockOpenOptions * 151 block_crypto_open_opts_init(QCryptoBlockFormat format, 152 QDict *opts, 153 Error **errp) 154 { 155 Visitor *v; 156 QCryptoBlockOpenOptions *ret = NULL; 157 Error *local_err = NULL; 158 159 ret = g_new0(QCryptoBlockOpenOptions, 1); 160 ret->format = format; 161 162 v = qobject_input_visitor_new_keyval(QOBJECT(opts)); 163 164 visit_start_struct(v, NULL, NULL, 0, &local_err); 165 if (local_err) { 166 goto out; 167 } 168 169 switch (format) { 170 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 171 visit_type_QCryptoBlockOptionsLUKS_members( 172 v, &ret->u.luks, &local_err); 173 break; 174 175 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 176 visit_type_QCryptoBlockOptionsQCow_members( 177 v, &ret->u.qcow, &local_err); 178 break; 179 180 default: 181 error_setg(&local_err, "Unsupported block format %d", format); 182 break; 183 } 184 if (!local_err) { 185 visit_check_struct(v, &local_err); 186 } 187 188 visit_end_struct(v, NULL); 189 190 out: 191 if (local_err) { 192 error_propagate(errp, local_err); 193 qapi_free_QCryptoBlockOpenOptions(ret); 194 ret = NULL; 195 } 196 visit_free(v); 197 return ret; 198 } 199 200 201 QCryptoBlockCreateOptions * 202 block_crypto_create_opts_init(QCryptoBlockFormat format, 203 QDict *opts, 204 Error **errp) 205 { 206 Visitor *v; 207 QCryptoBlockCreateOptions *ret = NULL; 208 Error *local_err = NULL; 209 210 ret = g_new0(QCryptoBlockCreateOptions, 1); 211 ret->format = format; 212 213 v = qobject_input_visitor_new_keyval(QOBJECT(opts)); 214 215 visit_start_struct(v, NULL, NULL, 0, &local_err); 216 if (local_err) { 217 goto out; 218 } 219 220 switch (format) { 221 case Q_CRYPTO_BLOCK_FORMAT_LUKS: 222 visit_type_QCryptoBlockCreateOptionsLUKS_members( 223 v, &ret->u.luks, &local_err); 224 break; 225 226 case Q_CRYPTO_BLOCK_FORMAT_QCOW: 227 visit_type_QCryptoBlockOptionsQCow_members( 228 v, &ret->u.qcow, &local_err); 229 break; 230 231 default: 232 error_setg(&local_err, "Unsupported block format %d", format); 233 break; 234 } 235 if (!local_err) { 236 visit_check_struct(v, &local_err); 237 } 238 239 visit_end_struct(v, NULL); 240 241 out: 242 if (local_err) { 243 error_propagate(errp, local_err); 244 qapi_free_QCryptoBlockCreateOptions(ret); 245 ret = NULL; 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 Error *local_err = NULL; 262 int ret = -EINVAL; 263 QCryptoBlockOpenOptions *open_opts = NULL; 264 unsigned int cflags = 0; 265 QDict *cryptoopts = NULL; 266 267 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 268 false, errp); 269 if (!bs->file) { 270 return -EINVAL; 271 } 272 273 bs->supported_write_flags = BDRV_REQ_FUA & 274 bs->file->bs->supported_write_flags; 275 276 opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); 277 qemu_opts_absorb_qdict(opts, options, &local_err); 278 if (local_err) { 279 error_propagate(errp, local_err); 280 goto cleanup; 281 } 282 283 cryptoopts = qemu_opts_to_qdict(opts, NULL); 284 285 open_opts = block_crypto_open_opts_init(format, cryptoopts, errp); 286 if (!open_opts) { 287 goto cleanup; 288 } 289 290 if (flags & BDRV_O_NO_IO) { 291 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 292 } 293 crypto->block = qcrypto_block_open(open_opts, NULL, 294 block_crypto_read_func, 295 bs, 296 cflags, 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 QDECREF(cryptoopts); 309 qapi_free_QCryptoBlockOpenOptions(open_opts); 310 return ret; 311 } 312 313 314 static int block_crypto_co_create_generic(BlockDriverState *bs, 315 int64_t size, 316 QCryptoBlockCreateOptions *opts, 317 Error **errp) 318 { 319 int ret; 320 BlockBackend *blk; 321 QCryptoBlock *crypto = NULL; 322 struct BlockCryptoCreateData data; 323 324 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 325 326 ret = blk_insert_bs(blk, bs, errp); 327 if (ret < 0) { 328 goto cleanup; 329 } 330 331 data = (struct BlockCryptoCreateData) { 332 .blk = blk, 333 .size = size, 334 }; 335 336 crypto = qcrypto_block_create(opts, NULL, 337 block_crypto_init_func, 338 block_crypto_write_func, 339 &data, 340 errp); 341 342 if (!crypto) { 343 ret = -EIO; 344 goto cleanup; 345 } 346 347 ret = 0; 348 cleanup: 349 qcrypto_block_free(crypto); 350 blk_unref(blk); 351 return ret; 352 } 353 354 static int block_crypto_truncate(BlockDriverState *bs, int64_t offset, 355 PreallocMode prealloc, Error **errp) 356 { 357 BlockCrypto *crypto = bs->opaque; 358 uint64_t payload_offset = 359 qcrypto_block_get_payload_offset(crypto->block); 360 assert(payload_offset < (INT64_MAX - offset)); 361 362 offset += payload_offset; 363 364 return bdrv_truncate(bs->file, offset, prealloc, errp); 365 } 366 367 static void block_crypto_close(BlockDriverState *bs) 368 { 369 BlockCrypto *crypto = bs->opaque; 370 qcrypto_block_free(crypto->block); 371 } 372 373 static int block_crypto_reopen_prepare(BDRVReopenState *state, 374 BlockReopenQueue *queue, Error **errp) 375 { 376 /* nothing needs checking */ 377 return 0; 378 } 379 380 /* 381 * 1 MB bounce buffer gives good performance / memory tradeoff 382 * when using cache=none|directsync. 383 */ 384 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024) 385 386 static coroutine_fn int 387 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 388 QEMUIOVector *qiov, int flags) 389 { 390 BlockCrypto *crypto = bs->opaque; 391 uint64_t cur_bytes; /* number of bytes in current iteration */ 392 uint64_t bytes_done = 0; 393 uint8_t *cipher_data = NULL; 394 QEMUIOVector hd_qiov; 395 int ret = 0; 396 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 397 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 398 399 assert(!flags); 400 assert(payload_offset < INT64_MAX); 401 assert(QEMU_IS_ALIGNED(offset, sector_size)); 402 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 403 404 qemu_iovec_init(&hd_qiov, qiov->niov); 405 406 /* Bounce buffer because we don't wish to expose cipher text 407 * in qiov which points to guest memory. 408 */ 409 cipher_data = 410 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 411 qiov->size)); 412 if (cipher_data == NULL) { 413 ret = -ENOMEM; 414 goto cleanup; 415 } 416 417 while (bytes) { 418 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 419 420 qemu_iovec_reset(&hd_qiov); 421 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 422 423 ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done, 424 cur_bytes, &hd_qiov, 0); 425 if (ret < 0) { 426 goto cleanup; 427 } 428 429 if (qcrypto_block_decrypt(crypto->block, offset + bytes_done, 430 cipher_data, cur_bytes, NULL) < 0) { 431 ret = -EIO; 432 goto cleanup; 433 } 434 435 qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes); 436 437 bytes -= cur_bytes; 438 bytes_done += cur_bytes; 439 } 440 441 cleanup: 442 qemu_iovec_destroy(&hd_qiov); 443 qemu_vfree(cipher_data); 444 445 return ret; 446 } 447 448 449 static coroutine_fn int 450 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 451 QEMUIOVector *qiov, int flags) 452 { 453 BlockCrypto *crypto = bs->opaque; 454 uint64_t cur_bytes; /* number of bytes in current iteration */ 455 uint64_t bytes_done = 0; 456 uint8_t *cipher_data = NULL; 457 QEMUIOVector hd_qiov; 458 int ret = 0; 459 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 460 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 461 462 assert(!(flags & ~BDRV_REQ_FUA)); 463 assert(payload_offset < INT64_MAX); 464 assert(QEMU_IS_ALIGNED(offset, sector_size)); 465 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 466 467 qemu_iovec_init(&hd_qiov, qiov->niov); 468 469 /* Bounce buffer because we're not permitted to touch 470 * contents of qiov - it points to guest memory. 471 */ 472 cipher_data = 473 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 474 qiov->size)); 475 if (cipher_data == NULL) { 476 ret = -ENOMEM; 477 goto cleanup; 478 } 479 480 while (bytes) { 481 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 482 483 qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes); 484 485 if (qcrypto_block_encrypt(crypto->block, offset + bytes_done, 486 cipher_data, cur_bytes, NULL) < 0) { 487 ret = -EIO; 488 goto cleanup; 489 } 490 491 qemu_iovec_reset(&hd_qiov); 492 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 493 494 ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done, 495 cur_bytes, &hd_qiov, flags); 496 if (ret < 0) { 497 goto cleanup; 498 } 499 500 bytes -= cur_bytes; 501 bytes_done += cur_bytes; 502 } 503 504 cleanup: 505 qemu_iovec_destroy(&hd_qiov); 506 qemu_vfree(cipher_data); 507 508 return ret; 509 } 510 511 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp) 512 { 513 BlockCrypto *crypto = bs->opaque; 514 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 515 bs->bl.request_alignment = sector_size; /* No sub-sector I/O */ 516 } 517 518 519 static int64_t block_crypto_getlength(BlockDriverState *bs) 520 { 521 BlockCrypto *crypto = bs->opaque; 522 int64_t len = bdrv_getlength(bs->file->bs); 523 524 uint64_t offset = qcrypto_block_get_payload_offset(crypto->block); 525 assert(offset < INT64_MAX); 526 527 if (offset > len) { 528 return -EIO; 529 } 530 531 len -= offset; 532 533 return len; 534 } 535 536 537 static int block_crypto_probe_luks(const uint8_t *buf, 538 int buf_size, 539 const char *filename) { 540 return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 541 buf, buf_size, filename); 542 } 543 544 static int block_crypto_open_luks(BlockDriverState *bs, 545 QDict *options, 546 int flags, 547 Error **errp) 548 { 549 return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 550 &block_crypto_runtime_opts_luks, 551 bs, options, flags, errp); 552 } 553 554 static int coroutine_fn 555 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp) 556 { 557 BlockdevCreateOptionsLUKS *luks_opts; 558 BlockDriverState *bs = NULL; 559 QCryptoBlockCreateOptions create_opts; 560 int ret; 561 562 assert(create_options->driver == BLOCKDEV_DRIVER_LUKS); 563 luks_opts = &create_options->u.luks; 564 565 bs = bdrv_open_blockdev_ref(luks_opts->file, errp); 566 if (bs == NULL) { 567 return -EIO; 568 } 569 570 create_opts = (QCryptoBlockCreateOptions) { 571 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 572 .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts), 573 }; 574 575 ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts, 576 errp); 577 if (ret < 0) { 578 goto fail; 579 } 580 581 ret = 0; 582 fail: 583 bdrv_unref(bs); 584 return ret; 585 } 586 587 static int coroutine_fn block_crypto_co_create_opts_luks(const char *filename, 588 QemuOpts *opts, 589 Error **errp) 590 { 591 QCryptoBlockCreateOptions *create_opts = NULL; 592 BlockDriverState *bs = NULL; 593 QDict *cryptoopts; 594 int64_t size; 595 int ret; 596 597 /* Parse options */ 598 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 599 600 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 601 &block_crypto_create_opts_luks, 602 true); 603 604 create_opts = block_crypto_create_opts_init(Q_CRYPTO_BLOCK_FORMAT_LUKS, 605 cryptoopts, errp); 606 if (!create_opts) { 607 ret = -EINVAL; 608 goto fail; 609 } 610 611 /* Create protocol layer */ 612 ret = bdrv_create_file(filename, opts, errp); 613 if (ret < 0) { 614 return ret; 615 } 616 617 bs = bdrv_open(filename, NULL, NULL, 618 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 619 if (!bs) { 620 ret = -EINVAL; 621 goto fail; 622 } 623 624 /* Create format layer */ 625 ret = block_crypto_co_create_generic(bs, size, create_opts, errp); 626 if (ret < 0) { 627 goto fail; 628 } 629 630 ret = 0; 631 fail: 632 bdrv_unref(bs); 633 qapi_free_QCryptoBlockCreateOptions(create_opts); 634 QDECREF(cryptoopts); 635 return ret; 636 } 637 638 static int block_crypto_get_info_luks(BlockDriverState *bs, 639 BlockDriverInfo *bdi) 640 { 641 BlockDriverInfo subbdi; 642 int ret; 643 644 ret = bdrv_get_info(bs->file->bs, &subbdi); 645 if (ret != 0) { 646 return ret; 647 } 648 649 bdi->unallocated_blocks_are_zero = false; 650 bdi->cluster_size = subbdi.cluster_size; 651 652 return 0; 653 } 654 655 static ImageInfoSpecific * 656 block_crypto_get_specific_info_luks(BlockDriverState *bs) 657 { 658 BlockCrypto *crypto = bs->opaque; 659 ImageInfoSpecific *spec_info; 660 QCryptoBlockInfo *info; 661 662 info = qcrypto_block_get_info(crypto->block, NULL); 663 if (!info) { 664 return NULL; 665 } 666 if (info->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) { 667 qapi_free_QCryptoBlockInfo(info); 668 return NULL; 669 } 670 671 spec_info = g_new(ImageInfoSpecific, 1); 672 spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; 673 spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); 674 *spec_info->u.luks.data = info->u.luks; 675 676 /* Blank out pointers we've just stolen to avoid double free */ 677 memset(&info->u.luks, 0, sizeof(info->u.luks)); 678 679 qapi_free_QCryptoBlockInfo(info); 680 681 return spec_info; 682 } 683 684 BlockDriver bdrv_crypto_luks = { 685 .format_name = "luks", 686 .instance_size = sizeof(BlockCrypto), 687 .bdrv_probe = block_crypto_probe_luks, 688 .bdrv_open = block_crypto_open_luks, 689 .bdrv_close = block_crypto_close, 690 .bdrv_child_perm = bdrv_format_default_perms, 691 .bdrv_co_create = block_crypto_co_create_luks, 692 .bdrv_co_create_opts = block_crypto_co_create_opts_luks, 693 .bdrv_truncate = block_crypto_truncate, 694 .create_opts = &block_crypto_create_opts_luks, 695 696 .bdrv_reopen_prepare = block_crypto_reopen_prepare, 697 .bdrv_refresh_limits = block_crypto_refresh_limits, 698 .bdrv_co_preadv = block_crypto_co_preadv, 699 .bdrv_co_pwritev = block_crypto_co_pwritev, 700 .bdrv_getlength = block_crypto_getlength, 701 .bdrv_get_info = block_crypto_get_info_luks, 702 .bdrv_get_specific_info = block_crypto_get_specific_info_luks, 703 }; 704 705 static void block_crypto_init(void) 706 { 707 bdrv_register(&bdrv_crypto_luks); 708 } 709 710 block_init(block_crypto_init); 711