Re: [security]: kernel ioctl()'s [2]

H.J. Lu (hjl@lucon.org)
Fri, 2 Jul 1999 17:16:58 -0700 (PDT)


>
>
> On Fri, 2 Jul 1999, H.J. Lu wrote:
>
> > > Chris Evans writes:
> > >
> > > > Oh yeah. So, question, what's the ext2_i.i_version used by?
> > > > I suppose I withdraw my objection to letting users set it!
> > >
> > > The NFS server is supposed to use i_version. Don't think of
> > > i_version as a file version like VMS has. The BSD name, i_gen,
> > > more accurately indicates that this is a generation number.
> >
> > The fixed knfsd does use ext2_i.i_version. Don't touch it.
>
> I don't intend to.... however, the original comment (by me) is that ext2
> exposes an ioctl() that lets users play with ext2_i.i_version arbitrarily.
> On files they own, anyway.
>
> Question. Could a malicious user interfere with/break knfsd by playing
> games with ext2_i.i_version values on their files?
>

It is possible that the NFS client gets a stale NFS filehandle when
ext2_i.i_version is changed.

-- 
H.J. Lu (hjl@gnu.org)

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