Re: [PATCH v2 1/2] tty: tty_io: update timestamps on all device nodes

From: Greg KH
Date: Tue Jun 13 2023 - 06:25:54 EST


On Tue, Jun 13, 2023 at 12:23:41PM +0200, Greg KH wrote:
> On Thu, Jun 08, 2023 at 07:52:54PM +0200, Michal Sekletar wrote:
> > On Thu, Jun 8, 2023 at 1:51 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > > So how are you protecting this from being an information leak like we
> > > have had in the past where you could monitor how many characters were
> > > being sent to the tty through a proc file? Seems like now you can just
> > > monitor any tty node in the system and get the same information, while
> > > today you can only do it for the tty devices you have permissions for,
> > > right?
> >
> > Hi Greg,
> >
> > I am not protecting against it in any way, but proposed changes are only
> > about timestamp updates which still happen in at least 8 seconds intervals
> > so exact timing of read/writes to tty can't be inferred. Frankly, I may
> > have misunderstood something. It would be great if you could mention a bit
> > more details about CVE you had in mind.
>
> Ah, I missed that this is in 8 second increments, nevermind then!
>

Note, I still can't take this series for the obvious reason in patch
2/2. Please fix.

thanks,

greg k-h