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
35typedef struct BlockCrypto BlockCrypto;
36
37struct BlockCrypto {
38 QCryptoBlock *block;
39};
40
41
42static 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
55static 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
74struct BlockCryptoCreateData {
75 BlockBackend *blk;
76 uint64_t size;
77 PreallocMode prealloc;
78};
79
80
81static 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
100static 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
121static 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
131static 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
152QCryptoBlockOpenOptions *
153block_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
170QCryptoBlockCreateOptions *
171block_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
188static 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
252static 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
299static int coroutine_fn
300block_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
317static void block_crypto_close(BlockDriverState *bs)
318{
319 BlockCrypto *crypto = bs->opaque;
320 qcrypto_block_free(crypto->block);
321}
322
323static 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
336static coroutine_fn int
337block_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
399static coroutine_fn int
400block_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
461static 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
469static 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
487static 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
494static 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
504static int coroutine_fn
505block_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;
537fail:
538 bdrv_unref(bs);
539 return ret;
540}
541
542static 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;
598fail:
599 bdrv_unref(bs);
600 qapi_free_QCryptoBlockCreateOptions(create_opts);
601 qobject_unref(cryptoopts);
602 return ret;
603}
604
605static 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
622static ImageInfoSpecific *
623block_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
648static const char *const block_crypto_strong_runtime_opts[] = {
649 BLOCK_CRYPTO_OPT_LUKS_KEY_SECRET,
650
651 NULL
652};
653
654static 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
679static void block_crypto_init(void)
680{
681 bdrv_register(&bdrv_crypto_luks);
682}
683
684block_init(block_crypto_init);
685