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block/vhdx: check error return of bdrv_getlength()

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Calls to bdrv_getlength() were not checking for error.  In vhdx.c, this
can lead to truncating an image file, so it is a definite bug.  In
vhdx-log.c, the path for improper behavior is less clear, but it is best
to check in any case.

Some minor code movement of the log_guid intialization, as well.

Reported-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Jeff Cody 2017-08-07 08:38:19 -04:00 committed by Kevin Wolf
parent 795be0621a
commit 3f910692c2
2 changed files with 26 additions and 6 deletions
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23
block/vhdx-log.c
View File

@ -491,6 +491,7 @@ static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s,
uint32_t cnt, sectors_read;
uint64_t new_file_size;
void *data = NULL;
int64_t file_length;
VHDXLogDescEntries *desc_entries = NULL;
VHDXLogEntryHeader hdr_tmp = { 0 };
@ -510,10 +511,15 @@ static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s,
if (ret < 0) {
goto exit;
}
file_length = bdrv_getlength(bs->file->bs);
if (file_length < 0) {
ret = file_length;
goto exit;
}
/* if the log shows a FlushedFileOffset larger than our current file
* size, then that means the file has been truncated / corrupted, and
* we must refused to open it / use it */
if (hdr_tmp.flushed_file_offset > bdrv_getlength(bs->file->bs)) {
if (hdr_tmp.flushed_file_offset > file_length) {
ret = -EINVAL;
goto exit;
}
@ -543,7 +549,7 @@ static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s,
goto exit;
}
}
if (bdrv_getlength(bs->file->bs) < desc_entries->hdr.last_file_offset) {
if (file_length < desc_entries->hdr.last_file_offset) {
new_file_size = desc_entries->hdr.last_file_offset;
if (new_file_size % (1024*1024)) {
/* round up to nearest 1MB boundary */
@ -851,6 +857,7 @@ static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s,
uint32_t partial_sectors = 0;
uint32_t bytes_written = 0;
uint64_t file_offset;
int64_t file_length;
VHDXHeader *header;
VHDXLogEntryHeader new_hdr;
VHDXLogDescriptor *new_desc = NULL;
@ -904,6 +911,12 @@ static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s,
sectors += partial_sectors;
file_length = bdrv_getlength(bs->file->bs);
if (file_length < 0) {
ret = file_length;
goto exit;
}
/* sectors is now how many sectors the data itself takes, not
* including the header and descriptor metadata */
@ -913,11 +926,11 @@ static int vhdx_log_write(BlockDriverState *bs, BDRVVHDXState *s,
.sequence_number = s->log.sequence,
.descriptor_count = sectors,
.reserved = 0,
.flushed_file_offset = bdrv_getlength(bs->file->bs),
.last_file_offset = bdrv_getlength(bs->file->bs),
.flushed_file_offset = file_length,
.last_file_offset = file_length,
.log_guid = header->log_guid,
};
new_hdr.log_guid = header->log_guid;
desc_sectors = vhdx_compute_desc_sectors(new_hdr.descriptor_count);

9
block/vhdx.c
View File

@ -1166,7 +1166,14 @@ exit:
static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
uint64_t *new_offset)
{
*new_offset = bdrv_getlength(bs->file->bs);
int64_t current_len;
current_len = bdrv_getlength(bs->file->bs);
if (current_len < 0) {
return current_len;
}
*new_offset = current_len;
/* per the spec, the address for a block is in units of 1MB */
*new_offset = ROUND_UP(*new_offset, 1024 * 1024);