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block/vhdx: add check for truncated image files

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qemu is currently not able to detect truncated vhdx image files.
Add a basic check if all allocated blocks are reachable at open and
report all errors during bdrv_co_check.

Signed-off-by: Peter Lieven <pl@kamp.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Peter Lieven 2019-09-10 17:26:22 +02:00 committed by Kevin Wolf
parent 22dbfdecc3
commit 6caaad46de
1 changed files with 103 additions and 17 deletions
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120
block/vhdx.c
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@ -24,6 +24,7 @@
#include "qemu/option.h"
#include "qemu/crc32c.h"
#include "qemu/bswap.h"
#include "qemu/error-report.h"
#include "vhdx.h"
#include "migration/blocker.h"
#include "qemu/uuid.h"
@ -235,6 +236,9 @@ static int vhdx_region_check(BDRVVHDXState *s, uint64_t start, uint64_t length)
end = start + length;
QLIST_FOREACH(r, &s->regions, entries) {
if (!((start >= r->end) || (end <= r->start))) {
error_report("VHDX region %" PRIu64 "-%" PRIu64 " overlaps with "
"region %" PRIu64 "-%." PRIu64, start, end, r->start,
r->end);
ret = -EINVAL;
goto exit;
}
@ -877,6 +881,95 @@ static void vhdx_calc_bat_entries(BDRVVHDXState *s)
}
static int vhdx_check_bat_entries(BlockDriverState *bs, int *errcnt)
{
BDRVVHDXState *s = bs->opaque;
int64_t image_file_size = bdrv_getlength(bs->file->bs);
uint64_t payblocks = s->chunk_ratio;
uint64_t i;
int ret = 0;
if (image_file_size < 0) {
error_report("Could not determinate VHDX image file size.");
return image_file_size;
}
for (i = 0; i < s->bat_entries; i++) {
if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
PAYLOAD_BLOCK_FULLY_PRESENT) {
uint64_t offset = s->bat[i] & VHDX_BAT_FILE_OFF_MASK;
/*
* Allow that the last block exists only partially. The VHDX spec
* states that the image file can only grow in blocksize increments,
* but QEMU created images with partial last blocks in the past.
*/
uint32_t block_length = MIN(s->block_size,
bs->total_sectors * BDRV_SECTOR_SIZE - i * s->block_size);
/*
* Check for BAT entry overflow.
*/
if (offset > INT64_MAX - s->block_size) {
error_report("VHDX BAT entry %" PRIu64 " offset overflow.", i);
ret = -EINVAL;
if (!errcnt) {
break;
}
(*errcnt)++;
}
/*
* Check if fully allocated BAT entries do not reside after
* end of the image file.
*/
if (offset >= image_file_size) {
error_report("VHDX BAT entry %" PRIu64 " start offset %" PRIu64
" points after end of file (%" PRIi64 "). Image"
" has probably been truncated.",
i, offset, image_file_size);
ret = -EINVAL;
if (!errcnt) {
break;
}
(*errcnt)++;
} else if (offset + block_length > image_file_size) {
error_report("VHDX BAT entry %" PRIu64 " end offset %" PRIu64
" points after end of file (%" PRIi64 "). Image"
" has probably been truncated.",
i, offset + block_length - 1, image_file_size);
ret = -EINVAL;
if (!errcnt) {
break;
}
(*errcnt)++;
}
/*
* verify populated BAT field file offsets against
* region table and log entries
*/
if (payblocks--) {
/* payload bat entries */
int ret2;
ret2 = vhdx_region_check(s, offset, s->block_size);
if (ret2 < 0) {
ret = -EINVAL;
if (!errcnt) {
break;
}
(*errcnt)++;
}
} else {
payblocks = s->chunk_ratio;
/*
* Once differencing files are supported, verify sector bitmap
* blocks here
*/
}
}
}
return ret;
}
static void vhdx_close(BlockDriverState *bs)
{
BDRVVHDXState *s = bs->opaque;
@ -981,25 +1074,15 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags,
goto fail;
}
uint64_t payblocks = s->chunk_ratio;
/* endian convert, and verify populated BAT field file offsets against
* region table and log entries */
/* endian convert populated BAT field entires */
for (i = 0; i < s->bat_entries; i++) {
s->bat[i] = le64_to_cpu(s->bat[i]);
if (payblocks--) {
/* payload bat entries */
if ((s->bat[i] & VHDX_BAT_STATE_BIT_MASK) ==
PAYLOAD_BLOCK_FULLY_PRESENT) {
ret = vhdx_region_check(s, s->bat[i] & VHDX_BAT_FILE_OFF_MASK,
s->block_size);
if (ret < 0) {
goto fail;
}
}
} else {
payblocks = s->chunk_ratio;
/* Once differencing files are supported, verify sector bitmap
* blocks here */
}
if (!(flags & BDRV_O_CHECK)) {
ret = vhdx_check_bat_entries(bs, NULL);
if (ret < 0) {
goto fail;
}
}
@ -2072,6 +2155,9 @@ static int coroutine_fn vhdx_co_check(BlockDriverState *bs,
if (s->log_replayed_on_open) {
result->corruptions_fixed++;
}
vhdx_check_bat_entries(bs, &result->corruptions);
return 0;
}