Re: [stable] [Stable-review] [18/74] xfs: prevent leakinguninitialized stack memory in FSGEOMETRY_V1

From: Greg KH
Date: Thu Apr 14 2011 - 14:31:55 EST


On Thu, Apr 14, 2011 at 03:54:45AM +0100, Ben Hutchings wrote:
> On Wed, 2011-04-13 at 08:50 -0700, Greg KH wrote:
> > 2.6.32-longterm review patch. If anyone has any objections, please let us know.
> >
> > ------------------
> >
> > From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
> >
> > commit c4d0c3b097f7584772316ee4d64a09fe0e4ddfca upstream.
> >
> > The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to
> > xfs_fs_geometry() with a version number of 3. This code path does not
> > fill in the logsunit member of the passed xfs_fsop_geom_t, leading to
> > the leaking of four bytes of uninitialized stack data to potentially
> > unprivileged callers.
> [...]
>
> This caused a serious regression and requires a second fix:
>
> commit af24ee9ea8d532e16883251a6684dfa1be8eec29
> Author: Alex Elder <aelder@xxxxxxx>
> Date: Tue Mar 1 17:50:00 2011 +0000
>
> xfs: zero proper structure size for geometry calls

Thanks for letting me know, I've queued up this patch as well.

greg k-h
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