qcow1: Stricter backing file length check

Like qcow2 since commit 6d33e8e7, error out on invalid lengths instead
of silently truncating them to 1023.

Also don't rely on bdrv_pread() catching integer overflows that make len
negative, but use unsigned variables in the first place.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
This commit is contained in:
Kevin Wolf 2014-05-08 13:35:09 +02:00
parent 46485de0cb
commit d66e5cee00
3 changed files with 23 additions and 2 deletions

View file

@ -97,7 +97,8 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
Error **errp)
{
BDRVQcowState *s = bs->opaque;
int len, i, shift, ret;
unsigned int len, i, shift;
int ret;
QCowHeader header;
ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
@ -202,7 +203,9 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
if (header.backing_file_offset != 0) {
len = header.backing_file_size;
if (len > 1023) {
len = 1023;
error_setg(errp, "Backing file name too long");
ret = -EINVAL;
goto fail;
}
ret = bdrv_pread(bs->file, header.backing_file_offset,
bs->backing_file, len);