On Wed, Jul 24, 2019 at 08:35:45AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Explicitly initialize the onstack structures to zero so we don't leak
> kernel memory into userspace when converting the in-core structure to
> the v1 ioctl structure.
>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/xfs/xfs_ioctl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index f193f7b288ca..44e1a290f053 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -719,7 +719,7 @@ xfs_fsbulkstat_one_fmt(
> struct xfs_ibulk *breq,
> const struct xfs_bulkstat *bstat)
> {
> - struct xfs_bstat bs1;
> + struct xfs_bstat bs1 = { 0 };
This sort of initialization is potentially problematic because some
versions of GCC will change it as a series of assignments (which doesn't
clear the struct hole). It's not clear to me the rules where GCC does
this and also I wish there were an option to disable that feature.
[ I am still out of office until the end of the month ]
regards,
dan carpenter
