Re: [PATCH v3 2/2] tty: Allow TIOCSTI to be disabled

From: Kees Cook
Date: Mon Jul 03 2023 - 15:41:07 EST


On Sun, Jul 02, 2023 at 02:00:23AM +0200, Samuel Thibault wrote:
> Kees Cook, le mer. 28 juin 2023 09:32:20 -0700, a ecrit:
> > On Wed, Jun 28, 2023 at 08:07:16AM +0200, Samuel Thibault wrote:
> > > Kees Cook, le mar. 27 juin 2023 19:48:45 -0700, a ecrit:
> > > > > Really, this a serious regression for the people affected by this.
> > > >
> > > > Can you send a patch adding a CAP_SYS_ADMIN exception?
> > >
> > > Sure!
> >
> > Thanks! (And be sure to use file->f_cred for the check[1], not "current",
> > that way brltty can open the tty and drop caps and still do the ioctl.)
>
> Actually brltty re-opens the various tty[1-6] consoles when the users
> switches, so I kept just testing capable(CAP_SYS_ADMIN).

Well that's frustrating. :P

--
Kees Cook