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