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From: Kees Cook <keescook@chromium.org>
To: Samuel Thibault <samuel.thibault@aquilenet.fr>,
	Kees Cook <kees@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jiri Slaby <jirislaby@kernel.org>,
	Simon Brand <simon.brand@postadigitale.de>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	Dave@mielke.cc
Subject: Re: [PATCH v3 2/2] tty: Allow TIOCSTI to be disabled
Date: Tue, 27 Jun 2023 19:48:45 -0700	[thread overview]
Message-ID: <202306271944.E80E1D0@keescook> (raw)
In-Reply-To: <20230625155625.s4kvy7m2vw74ow4i@begin>

On Sun, Jun 25, 2023 at 05:56:25PM +0200, Samuel Thibault wrote:
> > Can we perhaps just introduce a CAP_TIOCSTI that the brltty daemon would
> > be able to use? We could even make it only allow TIOCSTI on the linux
> > console (tty->ops == con_ops).

Does brltty run with CAP_SYS_ADMIN? That seems a sensible exception to
be made.

> *Please* comment on this so we can progress. ATM people are
> advising each other to set dev.tty.legacy_tiocsti=1, which is just
> counter-productive in terms of security...

So is there really no solution for brltty and TIOCSTI being disabled?
What is FreeBSD doing? I imagine it's the same situation there too,
though maybe there is just no support?

https://www.mail-archive.com/brltty@brltty.app/msg02892.html

> Really, this a serious regression for the people affected by this.

Can you send a patch adding a CAP_SYS_ADMIN exception?

-Kees

-- 
Kees Cook

  parent reply	other threads:[~2023-06-28  2:48 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-22 18:29 [PATCH v3 0/2] tty: Allow TIOCSTI to be disabled Kees Cook
2022-10-22 18:29 ` [PATCH v3 1/2] tty: Move sysctl setup into "core" tty logic Kees Cook
2022-10-22 18:29 ` [PATCH v3 2/2] tty: Allow TIOCSTI to be disabled Kees Cook
2022-11-15 13:17   ` Geert Uytterhoeven
2022-12-27 23:40   ` Samuel Thibault
2022-12-27 23:41     ` Samuel Thibault
2022-12-28  3:32     ` Kees Cook
2022-12-28 20:57       ` Samuel Thibault
2023-06-25 15:56         ` Samuel Thibault
2023-06-27 21:50           ` Samuel Thibault
2023-06-28  0:21             ` Paul Moore
2023-06-28  2:48           ` Kees Cook [this message]
2023-06-28  6:07             ` Samuel Thibault
2023-06-28 16:32               ` Kees Cook
2023-07-02  0:00                 ` Samuel Thibault
2023-07-03 19:41                   ` Kees Cook
2023-06-29 13:23               ` David Laight
2023-06-29 13:32                 ` Samuel Thibault
2022-11-02  2:15 ` [PATCH v3 0/2] " Kees Cook
2022-11-02  2:29   ` Greg Kroah-Hartman
2022-11-02  2:46     ` Kees Cook

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