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 "crypto.h" 34 35 typedef struct BlockCrypto BlockCrypto; 36 37 struct BlockCrypto { 38 QCryptoBlock *block; 39 }; 40 41 42 static int block_crypto_probe_generic(QCryptoBlockFormat format, 43 const uint8_t *buf, 44 int buf_size, 45 const char *filename) 46 { 47 if (qcrypto_block_has_format(format, buf, buf_size)) { 48 return 100; 49 } else { 50 return 0; 51 } 52 } 53 54 55 static ssize_t block_crypto_read_func(QCryptoBlock *block, 56 size_t offset, 57 uint8_t *buf, 58 size_t buflen, 59 void *opaque, 60 Error **errp) 61 { 62 BlockDriverState *bs = opaque; 63 ssize_t ret; 64 65 ret = bdrv_pread(bs->file, offset, buf, buflen); 66 if (ret < 0) { 67 error_setg_errno(errp, -ret, "Could not read encryption header"); 68 return ret; 69 } 70 return ret; 71 } 72 73 74 struct BlockCryptoCreateData { 75 BlockBackend *blk; 76 uint64_t size; 77 PreallocMode prealloc; 78 }; 79 80 81 static ssize_t block_crypto_write_func(QCryptoBlock *block, 82 size_t offset, 83 const uint8_t *buf, 84 size_t buflen, 85 void *opaque, 86 Error **errp) 87 { 88 struct BlockCryptoCreateData *data = opaque; 89 ssize_t ret; 90 91 ret = blk_pwrite(data->blk, offset, buf, buflen, 0); 92 if (ret < 0) { 93 error_setg_errno(errp, -ret, "Could not write encryption header"); 94 return ret; 95 } 96 return ret; 97 } 98 99 100 static ssize_t block_crypto_init_func(QCryptoBlock *block, 101 size_t headerlen, 102 void *opaque, 103 Error **errp) 104 { 105 struct BlockCryptoCreateData *data = opaque; 106 107 if (data->size > INT64_MAX || headerlen > INT64_MAX - data->size) { 108 error_setg(errp, "The requested file size is too large"); 109 return -EFBIG; 110 } 111 112 /* User provided size should reflect amount of space made 113 * available to the guest, so we must take account of that 114 * which will be used by the crypto header 115 */ 116 return blk_truncate(data->blk, data->size + headerlen, data->prealloc, 117 errp); 118 } 119 120 121 static QemuOptsList block_crypto_runtime_opts_luks = { 122 .name = "crypto", 123 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_runtime_opts_luks.head), 124 .desc = { 125 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 126 { /* end of list */ } 127 }, 128 }; 129 130 131 static QemuOptsList block_crypto_create_opts_luks = { 132 .name = "crypto", 133 .head = QTAILQ_HEAD_INITIALIZER(block_crypto_create_opts_luks.head), 134 .desc = { 135 { 136 .name = BLOCK_OPT_SIZE, 137 .type = QEMU_OPT_SIZE, 138 .help = "Virtual disk size" 139 }, 140 BLOCK_CRYPTO_OPT_DEF_LUKS_KEY_SECRET(""), 141 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_ALG(""), 142 BLOCK_CRYPTO_OPT_DEF_LUKS_CIPHER_MODE(""), 143 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_ALG(""), 144 BLOCK_CRYPTO_OPT_DEF_LUKS_IVGEN_HASH_ALG(""), 145 BLOCK_CRYPTO_OPT_DEF_LUKS_HASH_ALG(""), 146 BLOCK_CRYPTO_OPT_DEF_LUKS_ITER_TIME(""), 147 { /* end of list */ } 148 }, 149 }; 150 151 152 QCryptoBlockOpenOptions * 153 block_crypto_open_opts_init(QDict *opts, Error **errp) 154 { 155 Visitor *v; 156 QCryptoBlockOpenOptions *ret; 157 158 v = qobject_input_visitor_new_flat_confused(opts, errp); 159 if (!v) { 160 return NULL; 161 } 162 163 visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp); 164 165 visit_free(v); 166 return ret; 167 } 168 169 170 QCryptoBlockCreateOptions * 171 block_crypto_create_opts_init(QDict *opts, Error **errp) 172 { 173 Visitor *v; 174 QCryptoBlockCreateOptions *ret; 175 176 v = qobject_input_visitor_new_flat_confused(opts, errp); 177 if (!v) { 178 return NULL; 179 } 180 181 visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp); 182 183 visit_free(v); 184 return ret; 185 } 186 187 188 static int block_crypto_open_generic(QCryptoBlockFormat format, 189 QemuOptsList *opts_spec, 190 BlockDriverState *bs, 191 QDict *options, 192 int flags, 193 Error **errp) 194 { 195 BlockCrypto *crypto = bs->opaque; 196 QemuOpts *opts = NULL; 197 Error *local_err = NULL; 198 int ret = -EINVAL; 199 QCryptoBlockOpenOptions *open_opts = NULL; 200 unsigned int cflags = 0; 201 QDict *cryptoopts = NULL; 202 203 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 204 false, errp); 205 if (!bs->file) { 206 return -EINVAL; 207 } 208 209 bs->supported_write_flags = BDRV_REQ_FUA & 210 bs->file->bs->supported_write_flags; 211 212 opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); 213 qemu_opts_absorb_qdict(opts, options, &local_err); 214 if (local_err) { 215 error_propagate(errp, local_err); 216 goto cleanup; 217 } 218 219 cryptoopts = qemu_opts_to_qdict(opts, NULL); 220 qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format)); 221 222 open_opts = block_crypto_open_opts_init(cryptoopts, errp); 223 if (!open_opts) { 224 goto cleanup; 225 } 226 227 if (flags & BDRV_O_NO_IO) { 228 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 229 } 230 crypto->block = qcrypto_block_open(open_opts, NULL, 231 block_crypto_read_func, 232 bs, 233 cflags, 234 1, 235 errp); 236 237 if (!crypto->block) { 238 ret = -EIO; 239 goto cleanup; 240 } 241 242 bs->encrypted = true; 243 244 ret = 0; 245 cleanup: 246 qobject_unref(cryptoopts); 247 qapi_free_QCryptoBlockOpenOptions(open_opts); 248 return ret; 249 } 250 251 252 static int block_crypto_co_create_generic(BlockDriverState *bs, 253 int64_t size, 254 QCryptoBlockCreateOptions *opts, 255 PreallocMode prealloc, 256 Error **errp) 257 { 258 int ret; 259 BlockBackend *blk; 260 QCryptoBlock *crypto = NULL; 261 struct BlockCryptoCreateData data; 262 263 blk = blk_new(bdrv_get_aio_context(bs), 264 BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 265 266 ret = blk_insert_bs(blk, bs, errp); 267 if (ret < 0) { 268 goto cleanup; 269 } 270 271 if (prealloc == PREALLOC_MODE_METADATA) { 272 prealloc = PREALLOC_MODE_OFF; 273 } 274 275 data = (struct BlockCryptoCreateData) { 276 .blk = blk, 277 .size = size, 278 .prealloc = prealloc, 279 }; 280 281 crypto = qcrypto_block_create(opts, NULL, 282 block_crypto_init_func, 283 block_crypto_write_func, 284 &data, 285 errp); 286 287 if (!crypto) { 288 ret = -EIO; 289 goto cleanup; 290 } 291 292 ret = 0; 293 cleanup: 294 qcrypto_block_free(crypto); 295 blk_unref(blk); 296 return ret; 297 } 298 299 static int coroutine_fn 300 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, 301 PreallocMode prealloc, Error **errp) 302 { 303 BlockCrypto *crypto = bs->opaque; 304 uint64_t payload_offset = 305 qcrypto_block_get_payload_offset(crypto->block); 306 307 if (payload_offset > INT64_MAX - offset) { 308 error_setg(errp, "The requested file size is too large"); 309 return -EFBIG; 310 } 311 312 offset += payload_offset; 313 314 return bdrv_co_truncate(bs->file, offset, prealloc, errp); 315 } 316 317 static void block_crypto_close(BlockDriverState *bs) 318 { 319 BlockCrypto *crypto = bs->opaque; 320 qcrypto_block_free(crypto->block); 321 } 322 323 static int block_crypto_reopen_prepare(BDRVReopenState *state, 324 BlockReopenQueue *queue, Error **errp) 325 { 326 /* nothing needs checking */ 327 return 0; 328 } 329 330 /* 331 * 1 MB bounce buffer gives good performance / memory tradeoff 332 * when using cache=none|directsync. 333 */ 334 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024) 335 336 static coroutine_fn int 337 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 338 QEMUIOVector *qiov, int flags) 339 { 340 BlockCrypto *crypto = bs->opaque; 341 uint64_t cur_bytes; /* number of bytes in current iteration */ 342 uint64_t bytes_done = 0; 343 uint8_t *cipher_data = NULL; 344 QEMUIOVector hd_qiov; 345 int ret = 0; 346 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 347 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 348 349 assert(!flags); 350 assert(payload_offset < INT64_MAX); 351 assert(QEMU_IS_ALIGNED(offset, sector_size)); 352 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 353 354 qemu_iovec_init(&hd_qiov, qiov->niov); 355 356 /* Bounce buffer because we don't wish to expose cipher text 357 * in qiov which points to guest memory. 358 */ 359 cipher_data = 360 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 361 qiov->size)); 362 if (cipher_data == NULL) { 363 ret = -ENOMEM; 364 goto cleanup; 365 } 366 367 while (bytes) { 368 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 369 370 qemu_iovec_reset(&hd_qiov); 371 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 372 373 ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done, 374 cur_bytes, &hd_qiov, 0); 375 if (ret < 0) { 376 goto cleanup; 377 } 378 379 if (qcrypto_block_decrypt(crypto->block, offset + bytes_done, 380 cipher_data, cur_bytes, NULL) < 0) { 381 ret = -EIO; 382 goto cleanup; 383 } 384 385 qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes); 386 387 bytes -= cur_bytes; 388 bytes_done += cur_bytes; 389 } 390 391 cleanup: 392 qemu_iovec_destroy(&hd_qiov); 393 qemu_vfree(cipher_data); 394 395 return ret; 396 } 397 398 399 static coroutine_fn int 400 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 401 QEMUIOVector *qiov, int flags) 402 { 403 BlockCrypto *crypto = bs->opaque; 404 uint64_t cur_bytes; /* number of bytes in current iteration */ 405 uint64_t bytes_done = 0; 406 uint8_t *cipher_data = NULL; 407 QEMUIOVector hd_qiov; 408 int ret = 0; 409 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 410 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 411 412 assert(!(flags & ~BDRV_REQ_FUA)); 413 assert(payload_offset < INT64_MAX); 414 assert(QEMU_IS_ALIGNED(offset, sector_size)); 415 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 416 417 qemu_iovec_init(&hd_qiov, qiov->niov); 418 419 /* Bounce buffer because we're not permitted to touch 420 * contents of qiov - it points to guest memory. 421 */ 422 cipher_data = 423 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 424 qiov->size)); 425 if (cipher_data == NULL) { 426 ret = -ENOMEM; 427 goto cleanup; 428 } 429 430 while (bytes) { 431 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 432 433 qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes); 434 435 if (qcrypto_block_encrypt(crypto->block, offset + bytes_done, 436 cipher_data, cur_bytes, NULL) < 0) { 437 ret = -EIO; 438 goto cleanup; 439 } 440 441 qemu_iovec_reset(&hd_qiov); 442 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 443 444 ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done, 445 cur_bytes, &hd_qiov, flags); 446 if (ret < 0) { 447 goto cleanup; 448 } 449 450 bytes -= cur_bytes; 451 bytes_done += cur_bytes; 452 } 453 454 cleanup: 455 qemu_iovec_destroy(&hd_qiov); 456 qemu_vfree(cipher_data); 457 458 return ret; 459 } 460 461 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp) 462 { 463 BlockCrypto *crypto = bs->opaque; 464 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 465 bs->bl.request_alignment = sector_size; /* No sub-sector I/O */ 466 } 467 468 469 static int64_t block_crypto_getlength(BlockDriverState *bs) 470 { 471 BlockCrypto *crypto = bs->opaque; 472 int64_t len = bdrv_getlength(bs->file->bs); 473 474 uint64_t offset = qcrypto_block_get_payload_offset(crypto->block); 475 assert(offset < INT64_MAX); 476 477 if (offset > len) { 478 return -EIO; 479 } 480 481 len -= offset; 482 483 return len; 484 } 485 486 487 static int block_crypto_probe_luks(const uint8_t *buf, 488 int buf_size, 489 const char *filename) { 490 return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 491 buf, buf_size, filename); 492 } 493 494 static int block_crypto_open_luks(BlockDriverState *bs, 495 QDict *options, 496 int flags, 497 Error **errp) 498 { 499 return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 500 &block_crypto_runtime_opts_luks, 501 bs, options, flags, errp); 502 } 503 504 static int coroutine_fn 505 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp) 506 { 507 BlockdevCreateOptionsLUKS *luks_opts; 508 BlockDriverState *bs = NULL; 509 QCryptoBlockCreateOptions create_opts; 510 PreallocMode preallocation = PREALLOC_MODE_OFF; 511 int ret; 512 513 assert(create_options->driver == BLOCKDEV_DRIVER_LUKS); 514 luks_opts = &create_options->u.luks; 515 516 bs = bdrv_open_blockdev_ref(luks_opts->file, errp); 517 if (bs == NULL) { 518 return -EIO; 519 } 520 521 create_opts = (QCryptoBlockCreateOptions) { 522 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 523 .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts), 524 }; 525 526 if (luks_opts->has_preallocation) { 527 preallocation = luks_opts->preallocation; 528 } 529 530 ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts, 531 preallocation, errp); 532 if (ret < 0) { 533 goto fail; 534 } 535 536 ret = 0; 537 fail: 538 bdrv_unref(bs); 539 return ret; 540 } 541 542 static int coroutine_fn block_crypto_co_create_opts_luks(const char *filename, 543 QemuOpts *opts, 544 Error **errp) 545 { 546 QCryptoBlockCreateOptions *create_opts = NULL; 547 BlockDriverState *bs = NULL; 548 QDict *cryptoopts; 549 PreallocMode prealloc; 550 char *buf = NULL; 551 int64_t size; 552 int ret; 553 Error *local_err = NULL; 554 555 /* Parse options */ 556 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 557 558 buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC); 559 prealloc = qapi_enum_parse(&PreallocMode_lookup, buf, 560 PREALLOC_MODE_OFF, &local_err); 561 g_free(buf); 562 if (local_err) { 563 error_propagate(errp, local_err); 564 return -EINVAL; 565 } 566 567 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 568 &block_crypto_create_opts_luks, 569 true); 570 571 qdict_put_str(cryptoopts, "format", "luks"); 572 create_opts = block_crypto_create_opts_init(cryptoopts, errp); 573 if (!create_opts) { 574 ret = -EINVAL; 575 goto fail; 576 } 577 578 /* Create protocol layer */ 579 ret = bdrv_create_file(filename, opts, errp); 580 if (ret < 0) { 581 goto fail; 582 } 583 584 bs = bdrv_open(filename, NULL, NULL, 585 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 586 if (!bs) { 587 ret = -EINVAL; 588 goto fail; 589 } 590 591 /* Create format layer */ 592 ret = block_crypto_co_create_generic(bs, size, create_opts, prealloc, errp); 593 if (ret < 0) { 594 goto fail; 595 } 596 597 ret = 0; 598 fail: 599 bdrv_unref(bs); 600 qapi_free_QCryptoBlockCreateOptions(create_opts); 601 qobject_unref(cryptoopts); 602 return ret; 603 } 604 605 static int block_crypto_get_info_luks(BlockDriverState *bs, 606 BlockDriverInfo *bdi) 607 { 608 BlockDriverInfo subbdi; 609 int ret; 610 611 ret = bdrv_get_info(bs->file->bs, &subbdi); 612 if (ret != 0) { 613 return ret; 614 } 615 616 bdi->unallocated_blocks_are_zero = false; 617 bdi->cluster_size = subbdi.cluster_size; 618 619 return 0; 620 } 621 622 static ImageInfoSpecific * 623 block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) 624 { 625 BlockCrypto *crypto = bs->opaque; 626 ImageInfoSpecific *spec_info; 627 QCryptoBlockInfo *info; 628 629 info = qcrypto_block_get_info(crypto->block, errp); 630 if (!info) { 631 return NULL; 632 } 633 assert(info->format == Q_CRYPTO_BLOCK_FORMAT_LUKS); 634 635 spec_info = g_new(ImageInfoSpecific, 1); 636 spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; 637 spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); 638 *spec_info->u.luks.data = info->u.luks; 639 640 /* Blank out pointers we've just stolen to avoid double free */ 641 memset(&info->u.luks, 0, sizeof(info->u.luks)); 642 643 qapi_free_QCryptoBlockInfo(info); 644 645 return spec_info; 646 } 647 648 static const char *const block_crypto_strong_runtime_opts[] = { 649 BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET, 650 651 NULL 652 }; 653 654 static BlockDriver bdrv_crypto_luks = { 655 .format_name = "luks", 656 .instance_size = sizeof(BlockCrypto), 657 .bdrv_probe = block_crypto_probe_luks, 658 .bdrv_open = block_crypto_open_luks, 659 .bdrv_close = block_crypto_close, 660 /* This driver doesn't modify LUKS metadata except when creating image. 661 * Allow share-rw=on as a special case. */ 662 .bdrv_child_perm = bdrv_filter_default_perms, 663 .bdrv_co_create = block_crypto_co_create_luks, 664 .bdrv_co_create_opts = block_crypto_co_create_opts_luks, 665 .bdrv_co_truncate = block_crypto_co_truncate, 666 .create_opts = &block_crypto_create_opts_luks, 667 668 .bdrv_reopen_prepare = block_crypto_reopen_prepare, 669 .bdrv_refresh_limits = block_crypto_refresh_limits, 670 .bdrv_co_preadv = block_crypto_co_preadv, 671 .bdrv_co_pwritev = block_crypto_co_pwritev, 672 .bdrv_getlength = block_crypto_getlength, 673 .bdrv_get_info = block_crypto_get_info_luks, 674 .bdrv_get_specific_info = block_crypto_get_specific_info_luks, 675 676 .strong_runtime_opts = block_crypto_strong_runtime_opts, 677 }; 678 679 static void block_crypto_init(void) 680 { 681 bdrv_register(&bdrv_crypto_luks); 682 } 683 684 block_init(block_crypto_init); 685