block/parallels-ext.c - qemu - Git at Google

 /*
  * Support of Parallels Format Extension. It's a part of Parallels format
  * driver.
  *
  * Copyright (c) 2021 Virtuozzo International GmbH
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "block/block_int.h"
 #include "parallels.h"
 #include "crypto/hash.h"
 #include "qemu/uuid.h"

 #define PARALLELS_FORMAT_EXTENSION_MAGIC 0xAB234CEF23DCEA87ULL

 #define PARALLELS_END_OF_FEATURES_MAGIC 0x0ULL
 #define PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC 0x20385FAE252CB34AULL

 typedef struct ParallelsFormatExtensionHeader {
     uint64_t magic; /* PARALLELS_FORMAT_EXTENSION_MAGIC */
     uint8_t check_sum[16];
 } QEMU_PACKED ParallelsFormatExtensionHeader;

 typedef struct ParallelsFeatureHeader {
     uint64_t magic;
     uint64_t flags;
     uint32_t data_size;
     uint32_t _unused;
 } QEMU_PACKED ParallelsFeatureHeader;

 typedef struct ParallelsDirtyBitmapFeature {
     uint64_t size;
     uint8_t id[16];
     uint32_t granularity;
     uint32_t l1_size;
     /* L1 table follows */
 } QEMU_PACKED ParallelsDirtyBitmapFeature;

 /* Given L1 table read bitmap data from the image and populate @bitmap */
 static int parallels_load_bitmap_data(BlockDriverState *bs,
                                       const uint64_t *l1_table,
                                       uint32_t l1_size,
                                       BdrvDirtyBitmap *bitmap,
                                       Error **errp)
 {
     BDRVParallelsState *s = bs->opaque;
     int ret = 0;
     uint64_t offset, limit;
     uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
     uint8_t *buf = NULL;
     uint64_t i, tab_size =
         DIV_ROUND_UP(bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size),
                      s->cluster_size);

     if (tab_size != l1_size) {
         error_setg(errp, "Bitmap table size %" PRIu32 " does not correspond "
                    "to bitmap size and cluster size. Expected %" PRIu64,
                    l1_size, tab_size);
         return -EINVAL;
     }

     buf = qemu_blockalign(bs, s->cluster_size);
     limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap);
     for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
         uint64_t count = MIN(bm_size - offset, limit);
         uint64_t entry = l1_table[i];

         if (entry == 0) {
             /* No need to deserialize zeros because @bitmap is cleared. */
             continue;
         }

         if (entry == 1) {
             bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count, false);
         } else {
             ret = bdrv_pread(bs->file, entry << BDRV_SECTOR_BITS, buf,
                              s->cluster_size);
             if (ret < 0) {
                 error_setg_errno(errp, -ret,
                                  "Failed to read bitmap data cluster");
                 goto finish;
             }
             bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
                                                false);
         }
     }
     ret = 0;

     bdrv_dirty_bitmap_deserialize_finish(bitmap);

 finish:
     qemu_vfree(buf);

     return ret;
 }

 /*
  * @data buffer (of @data_size size) is the Dirty bitmaps feature which
  * consists of ParallelsDirtyBitmapFeature followed by L1 table.
  */
 static BdrvDirtyBitmap *parallels_load_bitmap(BlockDriverState *bs,
                                               uint8_t *data,
                                               size_t data_size,
                                               Error **errp)
 {
     int ret;
     ParallelsDirtyBitmapFeature bf;
     g_autofree uint64_t *l1_table = NULL;
     BdrvDirtyBitmap *bitmap;
     QemuUUID uuid;
     char uuidstr[UUID_FMT_LEN + 1];
     int i;

     if (data_size < sizeof(bf)) {
         error_setg(errp, "Too small Bitmap Feature area in Parallels Format "
                    "Extension: %zu bytes, expected at least %zu bytes",
                    data_size, sizeof(bf));
         return NULL;
     }
     memcpy(&bf, data, sizeof(bf));
     bf.size = le64_to_cpu(bf.size);
     bf.granularity = le32_to_cpu(bf.granularity) << BDRV_SECTOR_BITS;
     bf.l1_size = le32_to_cpu(bf.l1_size);
     data += sizeof(bf);
     data_size -= sizeof(bf);

     if (bf.size != bs->total_sectors) {
         error_setg(errp, "Bitmap size (in sectors) %" PRId64 " differs from "
                    "disk size in sectors %" PRId64, bf.size, bs->total_sectors);
         return NULL;
     }

     if (bf.l1_size * sizeof(uint64_t) > data_size) {
         error_setg(errp, "Bitmaps feature corrupted: l1 table exceeds "
                    "extension data_size");
         return NULL;
     }

     memcpy(&uuid, bf.id, sizeof(uuid));
     qemu_uuid_unparse(&uuid, uuidstr);
     bitmap = bdrv_create_dirty_bitmap(bs, bf.granularity, uuidstr, errp);
     if (!bitmap) {
         return NULL;
     }

     l1_table = g_new(uint64_t, bf.l1_size);
     for (i = 0; i < bf.l1_size; i++, data += sizeof(uint64_t)) {
         l1_table[i] = ldq_le_p(data);
     }

     ret = parallels_load_bitmap_data(bs, l1_table, bf.l1_size, bitmap, errp);
     if (ret < 0) {
         bdrv_release_dirty_bitmap(bitmap);
         return NULL;
     }

     /* We support format extension only for RO parallels images. */
     assert(!(bs->open_flags & BDRV_O_RDWR));
     bdrv_dirty_bitmap_set_readonly(bitmap, true);

     return bitmap;
 }

 static int parallels_parse_format_extension(BlockDriverState *bs,
                                             uint8_t *ext_cluster, Error **errp)
 {
     BDRVParallelsState *s = bs->opaque;
     int ret;
     int remaining = s->cluster_size;
     uint8_t *pos = ext_cluster;
     ParallelsFormatExtensionHeader eh;
     g_autofree uint8_t *hash = NULL;
     size_t hash_len = 0;
     GSList *bitmaps = NULL, *el;

     memcpy(&eh, pos, sizeof(eh));
     eh.magic = le64_to_cpu(eh.magic);
     pos += sizeof(eh);
     remaining -= sizeof(eh);

     if (eh.magic != PARALLELS_FORMAT_EXTENSION_MAGIC) {
         error_setg(errp, "Wrong parallels Format Extension magic: 0x%" PRIx64
                    ", expected: 0x%llx", eh.magic,
                    PARALLELS_FORMAT_EXTENSION_MAGIC);
         goto fail;
     }

     ret = qcrypto_hash_bytes(QCRYPTO_HASH_ALG_MD5, (char *)pos, remaining,
                              &hash, &hash_len, errp);
     if (ret < 0) {
         goto fail;
     }

     if (hash_len != sizeof(eh.check_sum) ||
         memcmp(hash, eh.check_sum, sizeof(eh.check_sum)) != 0) {
         error_setg(errp, "Wrong checksum in Format Extension header. Format "
                    "extension is corrupted.");
         goto fail;
     }

     while (true) {
         ParallelsFeatureHeader fh;
         BdrvDirtyBitmap *bitmap;

         if (remaining < sizeof(fh)) {
             error_setg(errp, "Can not read feature header, as remaining bytes "
                        "(%d) in Format Extension is less than Feature header "
                        "size (%zu)", remaining, sizeof(fh));
             goto fail;
         }

         memcpy(&fh, pos, sizeof(fh));
         pos += sizeof(fh);
         remaining -= sizeof(fh);

         fh.magic = le64_to_cpu(fh.magic);
         fh.flags = le64_to_cpu(fh.flags);
         fh.data_size = le32_to_cpu(fh.data_size);

         if (fh.flags) {
             error_setg(errp, "Flags for extension feature are unsupported");
             goto fail;
         }

         if (fh.data_size > remaining) {
             error_setg(errp, "Feature data_size exceedes Format Extension "
                        "cluster");
             goto fail;
         }

         switch (fh.magic) {
         case PARALLELS_END_OF_FEATURES_MAGIC:
             return 0;

         case PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC:
             bitmap = parallels_load_bitmap(bs, pos, fh.data_size, errp);
             if (!bitmap) {
                 goto fail;
             }
             bitmaps = g_slist_append(bitmaps, bitmap);
             break;

         default:
             error_setg(errp, "Unknown feature: 0x%" PRIu64, fh.magic);
             goto fail;
         }

         pos = ext_cluster + QEMU_ALIGN_UP(pos + fh.data_size - ext_cluster, 8);
     }

 fail:
     for (el = bitmaps; el; el = el->next) {
         bdrv_release_dirty_bitmap(el->data);
     }
     g_slist_free(bitmaps);

     return -EINVAL;
 }

 int parallels_read_format_extension(BlockDriverState *bs,
                                     int64_t ext_off, Error **errp)
 {
     BDRVParallelsState *s = bs->opaque;
     int ret;
     uint8_t *ext_cluster = qemu_blockalign(bs, s->cluster_size);

     assert(ext_off > 0);

     ret = bdrv_pread(bs->file, ext_off, ext_cluster, s->cluster_size);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Failed to read Format Extension cluster");
         goto out;
     }

     ret = parallels_parse_format_extension(bs, ext_cluster, errp);

 out:
     qemu_vfree(ext_cluster);

     return ret;
 }
	/*
	* Support of Parallels Format Extension. It's a part of Parallels format
	* driver.
	*
	* Copyright (c) 2021 Virtuozzo International GmbH
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	#include "qemu/osdep.h"
	#include "qapi/error.h"
	#include "block/block_int.h"
	#include "parallels.h"
	#include "crypto/hash.h"
	#include "qemu/uuid.h"

	#define PARALLELS_FORMAT_EXTENSION_MAGIC 0xAB234CEF23DCEA87ULL

	#define PARALLELS_END_OF_FEATURES_MAGIC 0x0ULL
	#define PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC 0x20385FAE252CB34AULL

	typedef struct ParallelsFormatExtensionHeader {
	uint64_t magic; /* PARALLELS_FORMAT_EXTENSION_MAGIC */
	uint8_t check_sum[16];
	} QEMU_PACKED ParallelsFormatExtensionHeader;

	typedef struct ParallelsFeatureHeader {
	uint64_t magic;
	uint64_t flags;
	uint32_t data_size;
	uint32_t _unused;
	} QEMU_PACKED ParallelsFeatureHeader;

	typedef struct ParallelsDirtyBitmapFeature {
	uint64_t size;
	uint8_t id[16];
	uint32_t granularity;
	uint32_t l1_size;
	/* L1 table follows */
	} QEMU_PACKED ParallelsDirtyBitmapFeature;

	/* Given L1 table read bitmap data from the image and populate @bitmap */
	static int parallels_load_bitmap_data(BlockDriverState *bs,
	const uint64_t *l1_table,
	uint32_t l1_size,
	BdrvDirtyBitmap *bitmap,
	Error **errp)
	{
	BDRVParallelsState *s = bs->opaque;
	int ret = 0;
	uint64_t offset, limit;
	uint64_t bm_size = bdrv_dirty_bitmap_size(bitmap);
	uint8_t *buf = NULL;
	uint64_t i, tab_size =
	DIV_ROUND_UP(bdrv_dirty_bitmap_serialization_size(bitmap, 0, bm_size),
	s->cluster_size);

	if (tab_size != l1_size) {
	error_setg(errp, "Bitmap table size %" PRIu32 " does not correspond "
	"to bitmap size and cluster size. Expected %" PRIu64,
	l1_size, tab_size);
	return -EINVAL;
	}

	buf = qemu_blockalign(bs, s->cluster_size);
	limit = bdrv_dirty_bitmap_serialization_coverage(s->cluster_size, bitmap);
	for (i = 0, offset = 0; i < tab_size; ++i, offset += limit) {
	uint64_t count = MIN(bm_size - offset, limit);
	uint64_t entry = l1_table[i];

	if (entry == 0) {
	/* No need to deserialize zeros because @bitmap is cleared. */
	continue;
	}

	if (entry == 1) {
	bdrv_dirty_bitmap_deserialize_ones(bitmap, offset, count, false);
	} else {
	ret = bdrv_pread(bs->file, entry << BDRV_SECTOR_BITS, buf,
	s->cluster_size);
	if (ret < 0) {
	error_setg_errno(errp, -ret,
	"Failed to read bitmap data cluster");
	goto finish;
	}
	bdrv_dirty_bitmap_deserialize_part(bitmap, buf, offset, count,
	false);
	}
	}
	ret = 0;

	bdrv_dirty_bitmap_deserialize_finish(bitmap);

	finish:
	qemu_vfree(buf);

	return ret;
	}

	/*
	* @data buffer (of @data_size size) is the Dirty bitmaps feature which
	* consists of ParallelsDirtyBitmapFeature followed by L1 table.
	*/
	static BdrvDirtyBitmap parallels_load_bitmap(BlockDriverState bs,
	uint8_t *data,
	size_t data_size,
	Error **errp)
	{
	int ret;
	ParallelsDirtyBitmapFeature bf;
	g_autofree uint64_t *l1_table = NULL;
	BdrvDirtyBitmap *bitmap;
	QemuUUID uuid;
	char uuidstr[UUID_FMT_LEN + 1];
	int i;

	if (data_size < sizeof(bf)) {
	error_setg(errp, "Too small Bitmap Feature area in Parallels Format "
	"Extension: %zu bytes, expected at least %zu bytes",
	data_size, sizeof(bf));
	return NULL;
	}
	memcpy(&bf, data, sizeof(bf));
	bf.size = le64_to_cpu(bf.size);
	bf.granularity = le32_to_cpu(bf.granularity) << BDRV_SECTOR_BITS;
	bf.l1_size = le32_to_cpu(bf.l1_size);
	data += sizeof(bf);
	data_size -= sizeof(bf);

	if (bf.size != bs->total_sectors) {
	error_setg(errp, "Bitmap size (in sectors) %" PRId64 " differs from "
	"disk size in sectors %" PRId64, bf.size, bs->total_sectors);
	return NULL;
	}

	if (bf.l1_size * sizeof(uint64_t) > data_size) {
	error_setg(errp, "Bitmaps feature corrupted: l1 table exceeds "
	"extension data_size");
	return NULL;
	}

	memcpy(&uuid, bf.id, sizeof(uuid));
	qemu_uuid_unparse(&uuid, uuidstr);
	bitmap = bdrv_create_dirty_bitmap(bs, bf.granularity, uuidstr, errp);
	if (!bitmap) {
	return NULL;
	}

	l1_table = g_new(uint64_t, bf.l1_size);
	for (i = 0; i < bf.l1_size; i++, data += sizeof(uint64_t)) {
	l1_table[i] = ldq_le_p(data);
	}

	ret = parallels_load_bitmap_data(bs, l1_table, bf.l1_size, bitmap, errp);
	if (ret < 0) {
	bdrv_release_dirty_bitmap(bitmap);
	return NULL;
	}

	/* We support format extension only for RO parallels images. */
	assert(!(bs->open_flags & BDRV_O_RDWR));
	bdrv_dirty_bitmap_set_readonly(bitmap, true);

	return bitmap;
	}

	static int parallels_parse_format_extension(BlockDriverState *bs,
	uint8_t ext_cluster, Error *errp)
	{
	BDRVParallelsState *s = bs->opaque;
	int ret;
	int remaining = s->cluster_size;
	uint8_t *pos = ext_cluster;
	ParallelsFormatExtensionHeader eh;
	g_autofree uint8_t *hash = NULL;
	size_t hash_len = 0;
	GSList bitmaps = NULL, el;

	memcpy(&eh, pos, sizeof(eh));
	eh.magic = le64_to_cpu(eh.magic);
	pos += sizeof(eh);
	remaining -= sizeof(eh);

	if (eh.magic != PARALLELS_FORMAT_EXTENSION_MAGIC) {
	error_setg(errp, "Wrong parallels Format Extension magic: 0x%" PRIx64
	", expected: 0x%llx", eh.magic,
	PARALLELS_FORMAT_EXTENSION_MAGIC);
	goto fail;
	}

	ret = qcrypto_hash_bytes(QCRYPTO_HASH_ALG_MD5, (char *)pos, remaining,
	&hash, &hash_len, errp);
	if (ret < 0) {
	goto fail;
	}

	if (hash_len != sizeof(eh.check_sum) \|\|
	memcmp(hash, eh.check_sum, sizeof(eh.check_sum)) != 0) {
	error_setg(errp, "Wrong checksum in Format Extension header. Format "
	"extension is corrupted.");
	goto fail;
	}

	while (true) {
	ParallelsFeatureHeader fh;
	BdrvDirtyBitmap *bitmap;

	if (remaining < sizeof(fh)) {
	error_setg(errp, "Can not read feature header, as remaining bytes "
	"(%d) in Format Extension is less than Feature header "
	"size (%zu)", remaining, sizeof(fh));
	goto fail;
	}

	memcpy(&fh, pos, sizeof(fh));
	pos += sizeof(fh);
	remaining -= sizeof(fh);

	fh.magic = le64_to_cpu(fh.magic);
	fh.flags = le64_to_cpu(fh.flags);
	fh.data_size = le32_to_cpu(fh.data_size);

	if (fh.flags) {
	error_setg(errp, "Flags for extension feature are unsupported");
	goto fail;
	}

	if (fh.data_size > remaining) {
	error_setg(errp, "Feature data_size exceedes Format Extension "
	"cluster");
	goto fail;
	}

	switch (fh.magic) {
	case PARALLELS_END_OF_FEATURES_MAGIC:
	return 0;

	case PARALLELS_DIRTY_BITMAP_FEATURE_MAGIC:
	bitmap = parallels_load_bitmap(bs, pos, fh.data_size, errp);
	if (!bitmap) {
	goto fail;
	}
	bitmaps = g_slist_append(bitmaps, bitmap);
	break;

	default:
	error_setg(errp, "Unknown feature: 0x%" PRIu64, fh.magic);
	goto fail;
	}

	pos = ext_cluster + QEMU_ALIGN_UP(pos + fh.data_size - ext_cluster, 8);
	}

	fail:
	for (el = bitmaps; el; el = el->next) {
	bdrv_release_dirty_bitmap(el->data);
	}
	g_slist_free(bitmaps);

	return -EINVAL;
	}

	int parallels_read_format_extension(BlockDriverState *bs,
	int64_t ext_off, Error **errp)
	{
	BDRVParallelsState *s = bs->opaque;
	int ret;
	uint8_t *ext_cluster = qemu_blockalign(bs, s->cluster_size);

	assert(ext_off > 0);

	ret = bdrv_pread(bs->file, ext_off, ext_cluster, s->cluster_size);
	if (ret < 0) {
	error_setg_errno(errp, -ret, "Failed to read Format Extension cluster");
	goto out;
	}

	ret = parallels_parse_format_extension(bs, ext_cluster, errp);

	out:
	qemu_vfree(ext_cluster);

	return ret;
	}