Re: [PATCH v2 01/20] NFS: Avoid cross-structure casting

[Christoph Hellwig]

On Fri, May 26, 2017 at 01:17:05PM -0700, Kees Cook wrote:
> When the call to nfs_devname() fails, the error path attempts to retain
> the error via the mnt variable, but this requires a cast across very
> different types (char * to struct vfsmount *), which the upcoming
> structure layout randomization plugin flags as being potentially
> dangerous in the face of randomization. This is a false positive, but
> what this code actually wants to do is retain the error value, so this
> patch explicitly sets it, instead of using what seems to be an
> unexpected cast.
> 
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Acked-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>

Looks good:

Reviewed-by: Christoph Hellwig <hch@xxxxxx>

And I think we should get this (and the other cast patches) in ASAP,
independent of the fat of the randstruct plugin.