On Mon, Aug 07, 2017 at 12:46:30PM +0200, Kevin Wolf wrote: > Am 07.08.2017 um 05:08 hat Jeff Cody geschrieben: > > 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. > > > > Reported-by: Markus Armbruster <arm...@redhat.com> > > Signed-off-by: Jeff Cody <jc...@redhat.com> > > --- > > block/vhdx-log.c | 20 ++++++++++++++++---- > > block/vhdx.c | 9 ++++++++- > > 2 files changed, 24 insertions(+), 5 deletions(-) > > > > diff --git a/block/vhdx-log.c b/block/vhdx-log.c > > index 01278f3..fd4e7af 100644 > > --- a/block/vhdx-log.c > > +++ b/block/vhdx-log.c > > @@ -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 */ > > The vhdx_log_flush() part looks good, but it made me notice a > bdrv_flush() in the same function where the return value isn't checked. > I'm almost sure that this is a bug. >
I'll add 2 more simple patches to the series: one for bdrv_flush(), and one for the unchecked bdrv_truncate() as well. > > @@ -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; > > @@ -913,10 +920,15 @@ 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), > > }; > > > > + file_length = bdrv_getlength(bs->file->bs); > > + if (file_length < 0) { > > + ret = file_length; > > + goto exit; > > + } > > + new_hdr.flushed_file_offset = file_length; > > + new_hdr.last_file_offset = file_length; > > new_hdr.log_guid = header->log_guid; > > If you move the bdrv_getlength() above the initialisation of new_hdr, > you could keep these fields in the designated initialiser, which should > be better for readability. > > I also don't know why .log_guid isn't part if it, could be moved, too. > > > desc_sectors = vhdx_compute_desc_sectors(new_hdr.descriptor_count); > > diff --git a/block/vhdx.c b/block/vhdx.c > > index a9cecd2..6a14999 100644 > > --- a/block/vhdx.c > > +++ b/block/vhdx.c > > @@ -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; > > + } > > Don't you want the empty line to be between declaration and code rather > than assignment and check? > > > + *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); > > So the code looks correct, but we could make it a little nicer in a v2. > Yep, thanks. I'll address all those cleanups you mentioned in v2.