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/option.h" 32 #include "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(QDict *opts, Error **errp) 152 { 153 Visitor *v; 154 QCryptoBlockOpenOptions *ret; 155 156 v = qobject_input_visitor_new_flat_confused(opts, errp); 157 if (!v) { 158 return NULL; 159 } 160 161 visit_type_QCryptoBlockOpenOptions(v, NULL, &ret, errp); 162 163 visit_free(v); 164 return ret; 165 } 166 167 168 QCryptoBlockCreateOptions * 169 block_crypto_create_opts_init(QDict *opts, Error **errp) 170 { 171 Visitor *v; 172 QCryptoBlockCreateOptions *ret; 173 174 v = qobject_input_visitor_new_flat_confused(opts, errp); 175 if (!v) { 176 return NULL; 177 } 178 179 visit_type_QCryptoBlockCreateOptions(v, NULL, &ret, errp); 180 181 visit_free(v); 182 return ret; 183 } 184 185 186 static int block_crypto_open_generic(QCryptoBlockFormat format, 187 QemuOptsList *opts_spec, 188 BlockDriverState *bs, 189 QDict *options, 190 int flags, 191 Error **errp) 192 { 193 BlockCrypto *crypto = bs->opaque; 194 QemuOpts *opts = NULL; 195 Error *local_err = NULL; 196 int ret = -EINVAL; 197 QCryptoBlockOpenOptions *open_opts = NULL; 198 unsigned int cflags = 0; 199 QDict *cryptoopts = NULL; 200 201 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 202 false, errp); 203 if (!bs->file) { 204 return -EINVAL; 205 } 206 207 bs->supported_write_flags = BDRV_REQ_FUA & 208 bs->file->bs->supported_write_flags; 209 210 opts = qemu_opts_create(opts_spec, NULL, 0, &error_abort); 211 qemu_opts_absorb_qdict(opts, options, &local_err); 212 if (local_err) { 213 error_propagate(errp, local_err); 214 goto cleanup; 215 } 216 217 cryptoopts = qemu_opts_to_qdict(opts, NULL); 218 qdict_put_str(cryptoopts, "format", QCryptoBlockFormat_str(format)); 219 220 open_opts = block_crypto_open_opts_init(cryptoopts, errp); 221 if (!open_opts) { 222 goto cleanup; 223 } 224 225 if (flags & BDRV_O_NO_IO) { 226 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 227 } 228 crypto->block = qcrypto_block_open(open_opts, NULL, 229 block_crypto_read_func, 230 bs, 231 cflags, 232 1, 233 errp); 234 235 if (!crypto->block) { 236 ret = -EIO; 237 goto cleanup; 238 } 239 240 bs->encrypted = true; 241 242 ret = 0; 243 cleanup: 244 qobject_unref(cryptoopts); 245 qapi_free_QCryptoBlockOpenOptions(open_opts); 246 return ret; 247 } 248 249 250 static int block_crypto_co_create_generic(BlockDriverState *bs, 251 int64_t size, 252 QCryptoBlockCreateOptions *opts, 253 Error **errp) 254 { 255 int ret; 256 BlockBackend *blk; 257 QCryptoBlock *crypto = NULL; 258 struct BlockCryptoCreateData data; 259 260 blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 261 262 ret = blk_insert_bs(blk, bs, errp); 263 if (ret < 0) { 264 goto cleanup; 265 } 266 267 data = (struct BlockCryptoCreateData) { 268 .blk = blk, 269 .size = size, 270 }; 271 272 crypto = qcrypto_block_create(opts, NULL, 273 block_crypto_init_func, 274 block_crypto_write_func, 275 &data, 276 errp); 277 278 if (!crypto) { 279 ret = -EIO; 280 goto cleanup; 281 } 282 283 ret = 0; 284 cleanup: 285 qcrypto_block_free(crypto); 286 blk_unref(blk); 287 return ret; 288 } 289 290 static int coroutine_fn 291 block_crypto_co_truncate(BlockDriverState *bs, int64_t offset, 292 PreallocMode prealloc, Error **errp) 293 { 294 BlockCrypto *crypto = bs->opaque; 295 uint64_t payload_offset = 296 qcrypto_block_get_payload_offset(crypto->block); 297 298 if (payload_offset > INT64_MAX - offset) { 299 error_setg(errp, "The requested file size is too large"); 300 return -EFBIG; 301 } 302 303 offset += payload_offset; 304 305 return bdrv_co_truncate(bs->file, offset, prealloc, errp); 306 } 307 308 static void block_crypto_close(BlockDriverState *bs) 309 { 310 BlockCrypto *crypto = bs->opaque; 311 qcrypto_block_free(crypto->block); 312 } 313 314 static int block_crypto_reopen_prepare(BDRVReopenState *state, 315 BlockReopenQueue *queue, Error **errp) 316 { 317 /* nothing needs checking */ 318 return 0; 319 } 320 321 /* 322 * 1 MB bounce buffer gives good performance / memory tradeoff 323 * when using cache=none|directsync. 324 */ 325 #define BLOCK_CRYPTO_MAX_IO_SIZE (1024 * 1024) 326 327 static coroutine_fn int 328 block_crypto_co_preadv(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 329 QEMUIOVector *qiov, int flags) 330 { 331 BlockCrypto *crypto = bs->opaque; 332 uint64_t cur_bytes; /* number of bytes in current iteration */ 333 uint64_t bytes_done = 0; 334 uint8_t *cipher_data = NULL; 335 QEMUIOVector hd_qiov; 336 int ret = 0; 337 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 338 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 339 340 assert(!flags); 341 assert(payload_offset < INT64_MAX); 342 assert(QEMU_IS_ALIGNED(offset, sector_size)); 343 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 344 345 qemu_iovec_init(&hd_qiov, qiov->niov); 346 347 /* Bounce buffer because we don't wish to expose cipher text 348 * in qiov which points to guest memory. 349 */ 350 cipher_data = 351 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 352 qiov->size)); 353 if (cipher_data == NULL) { 354 ret = -ENOMEM; 355 goto cleanup; 356 } 357 358 while (bytes) { 359 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 360 361 qemu_iovec_reset(&hd_qiov); 362 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 363 364 ret = bdrv_co_preadv(bs->file, payload_offset + offset + bytes_done, 365 cur_bytes, &hd_qiov, 0); 366 if (ret < 0) { 367 goto cleanup; 368 } 369 370 if (qcrypto_block_decrypt(crypto->block, offset + bytes_done, 371 cipher_data, cur_bytes, NULL) < 0) { 372 ret = -EIO; 373 goto cleanup; 374 } 375 376 qemu_iovec_from_buf(qiov, bytes_done, cipher_data, cur_bytes); 377 378 bytes -= cur_bytes; 379 bytes_done += cur_bytes; 380 } 381 382 cleanup: 383 qemu_iovec_destroy(&hd_qiov); 384 qemu_vfree(cipher_data); 385 386 return ret; 387 } 388 389 390 static coroutine_fn int 391 block_crypto_co_pwritev(BlockDriverState *bs, uint64_t offset, uint64_t bytes, 392 QEMUIOVector *qiov, int flags) 393 { 394 BlockCrypto *crypto = bs->opaque; 395 uint64_t cur_bytes; /* number of bytes in current iteration */ 396 uint64_t bytes_done = 0; 397 uint8_t *cipher_data = NULL; 398 QEMUIOVector hd_qiov; 399 int ret = 0; 400 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 401 uint64_t payload_offset = qcrypto_block_get_payload_offset(crypto->block); 402 403 assert(!(flags & ~BDRV_REQ_FUA)); 404 assert(payload_offset < INT64_MAX); 405 assert(QEMU_IS_ALIGNED(offset, sector_size)); 406 assert(QEMU_IS_ALIGNED(bytes, sector_size)); 407 408 qemu_iovec_init(&hd_qiov, qiov->niov); 409 410 /* Bounce buffer because we're not permitted to touch 411 * contents of qiov - it points to guest memory. 412 */ 413 cipher_data = 414 qemu_try_blockalign(bs->file->bs, MIN(BLOCK_CRYPTO_MAX_IO_SIZE, 415 qiov->size)); 416 if (cipher_data == NULL) { 417 ret = -ENOMEM; 418 goto cleanup; 419 } 420 421 while (bytes) { 422 cur_bytes = MIN(bytes, BLOCK_CRYPTO_MAX_IO_SIZE); 423 424 qemu_iovec_to_buf(qiov, bytes_done, cipher_data, cur_bytes); 425 426 if (qcrypto_block_encrypt(crypto->block, offset + bytes_done, 427 cipher_data, cur_bytes, NULL) < 0) { 428 ret = -EIO; 429 goto cleanup; 430 } 431 432 qemu_iovec_reset(&hd_qiov); 433 qemu_iovec_add(&hd_qiov, cipher_data, cur_bytes); 434 435 ret = bdrv_co_pwritev(bs->file, payload_offset + offset + bytes_done, 436 cur_bytes, &hd_qiov, flags); 437 if (ret < 0) { 438 goto cleanup; 439 } 440 441 bytes -= cur_bytes; 442 bytes_done += cur_bytes; 443 } 444 445 cleanup: 446 qemu_iovec_destroy(&hd_qiov); 447 qemu_vfree(cipher_data); 448 449 return ret; 450 } 451 452 static void block_crypto_refresh_limits(BlockDriverState *bs, Error **errp) 453 { 454 BlockCrypto *crypto = bs->opaque; 455 uint64_t sector_size = qcrypto_block_get_sector_size(crypto->block); 456 bs->bl.request_alignment = sector_size; /* No sub-sector I/O */ 457 } 458 459 460 static int64_t block_crypto_getlength(BlockDriverState *bs) 461 { 462 BlockCrypto *crypto = bs->opaque; 463 int64_t len = bdrv_getlength(bs->file->bs); 464 465 uint64_t offset = qcrypto_block_get_payload_offset(crypto->block); 466 assert(offset < INT64_MAX); 467 468 if (offset > len) { 469 return -EIO; 470 } 471 472 len -= offset; 473 474 return len; 475 } 476 477 478 static int block_crypto_probe_luks(const uint8_t *buf, 479 int buf_size, 480 const char *filename) { 481 return block_crypto_probe_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 482 buf, buf_size, filename); 483 } 484 485 static int block_crypto_open_luks(BlockDriverState *bs, 486 QDict *options, 487 int flags, 488 Error **errp) 489 { 490 return block_crypto_open_generic(Q_CRYPTO_BLOCK_FORMAT_LUKS, 491 &block_crypto_runtime_opts_luks, 492 bs, options, flags, errp); 493 } 494 495 static int coroutine_fn 496 block_crypto_co_create_luks(BlockdevCreateOptions *create_options, Error **errp) 497 { 498 BlockdevCreateOptionsLUKS *luks_opts; 499 BlockDriverState *bs = NULL; 500 QCryptoBlockCreateOptions create_opts; 501 int ret; 502 503 assert(create_options->driver == BLOCKDEV_DRIVER_LUKS); 504 luks_opts = &create_options->u.luks; 505 506 bs = bdrv_open_blockdev_ref(luks_opts->file, errp); 507 if (bs == NULL) { 508 return -EIO; 509 } 510 511 create_opts = (QCryptoBlockCreateOptions) { 512 .format = Q_CRYPTO_BLOCK_FORMAT_LUKS, 513 .u.luks = *qapi_BlockdevCreateOptionsLUKS_base(luks_opts), 514 }; 515 516 ret = block_crypto_co_create_generic(bs, luks_opts->size, &create_opts, 517 errp); 518 if (ret < 0) { 519 goto fail; 520 } 521 522 ret = 0; 523 fail: 524 bdrv_unref(bs); 525 return ret; 526 } 527 528 static int coroutine_fn block_crypto_co_create_opts_luks(const char *filename, 529 QemuOpts *opts, 530 Error **errp) 531 { 532 QCryptoBlockCreateOptions *create_opts = NULL; 533 BlockDriverState *bs = NULL; 534 QDict *cryptoopts; 535 int64_t size; 536 int ret; 537 538 /* Parse options */ 539 size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0); 540 541 cryptoopts = qemu_opts_to_qdict_filtered(opts, NULL, 542 &block_crypto_create_opts_luks, 543 true); 544 545 qdict_put_str(cryptoopts, "format", "luks"); 546 create_opts = block_crypto_create_opts_init(cryptoopts, errp); 547 if (!create_opts) { 548 ret = -EINVAL; 549 goto fail; 550 } 551 552 /* Create protocol layer */ 553 ret = bdrv_create_file(filename, opts, errp); 554 if (ret < 0) { 555 goto fail; 556 } 557 558 bs = bdrv_open(filename, NULL, NULL, 559 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 560 if (!bs) { 561 ret = -EINVAL; 562 goto fail; 563 } 564 565 /* Create format layer */ 566 ret = block_crypto_co_create_generic(bs, size, create_opts, errp); 567 if (ret < 0) { 568 goto fail; 569 } 570 571 ret = 0; 572 fail: 573 bdrv_unref(bs); 574 qapi_free_QCryptoBlockCreateOptions(create_opts); 575 qobject_unref(cryptoopts); 576 return ret; 577 } 578 579 static int block_crypto_get_info_luks(BlockDriverState *bs, 580 BlockDriverInfo *bdi) 581 { 582 BlockDriverInfo subbdi; 583 int ret; 584 585 ret = bdrv_get_info(bs->file->bs, &subbdi); 586 if (ret != 0) { 587 return ret; 588 } 589 590 bdi->unallocated_blocks_are_zero = false; 591 bdi->cluster_size = subbdi.cluster_size; 592 593 return 0; 594 } 595 596 static ImageInfoSpecific * 597 block_crypto_get_specific_info_luks(BlockDriverState *bs) 598 { 599 BlockCrypto *crypto = bs->opaque; 600 ImageInfoSpecific *spec_info; 601 QCryptoBlockInfo *info; 602 603 info = qcrypto_block_get_info(crypto->block, NULL); 604 if (!info) { 605 return NULL; 606 } 607 if (info->format != Q_CRYPTO_BLOCK_FORMAT_LUKS) { 608 qapi_free_QCryptoBlockInfo(info); 609 return NULL; 610 } 611 612 spec_info = g_new(ImageInfoSpecific, 1); 613 spec_info->type = IMAGE_INFO_SPECIFIC_KIND_LUKS; 614 spec_info->u.luks.data = g_new(QCryptoBlockInfoLUKS, 1); 615 *spec_info->u.luks.data = info->u.luks; 616 617 /* Blank out pointers we've just stolen to avoid double free */ 618 memset(&info->u.luks, 0, sizeof(info->u.luks)); 619 620 qapi_free_QCryptoBlockInfo(info); 621 622 return spec_info; 623 } 624 625 BlockDriver bdrv_crypto_luks = { 626 .format_name = "luks", 627 .instance_size = sizeof(BlockCrypto), 628 .bdrv_probe = block_crypto_probe_luks, 629 .bdrv_open = block_crypto_open_luks, 630 .bdrv_close = block_crypto_close, 631 /* This driver doesn't modify LUKS metadata except when creating image. 632 * Allow share-rw=on as a special case. */ 633 .bdrv_child_perm = bdrv_filter_default_perms, 634 .bdrv_co_create = block_crypto_co_create_luks, 635 .bdrv_co_create_opts = block_crypto_co_create_opts_luks, 636 .bdrv_co_truncate = block_crypto_co_truncate, 637 .create_opts = &block_crypto_create_opts_luks, 638 639 .bdrv_reopen_prepare = block_crypto_reopen_prepare, 640 .bdrv_refresh_limits = block_crypto_refresh_limits, 641 .bdrv_co_preadv = block_crypto_co_preadv, 642 .bdrv_co_pwritev = block_crypto_co_pwritev, 643 .bdrv_getlength = block_crypto_getlength, 644 .bdrv_get_info = block_crypto_get_info_luks, 645 .bdrv_get_specific_info = block_crypto_get_specific_info_luks, 646 }; 647 648 static void block_crypto_init(void) 649 { 650 bdrv_register(&bdrv_crypto_luks); 651 } 652 653 block_init(block_crypto_init); 654