Received-SPF: pass (google.com: domain of linux-kernel+bounces-16026-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Thu, 04 Jan 2024 10:34:14 +1300
From: Oliver Giles <ohw.giles@gmail.com>
Subject: Re: [PATCH v2 08/11] tty: splice_read: disable
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>, Ahelenia =?iso-8859-2?q?Ziemia=F1ska?=
	<nabijaczleweli@nabijaczleweli.xyz>, Jens Axboe <axboe@kernel.dk>,
	Christian Brauner <brauner@kernel.org>, Alexander Viro
	<viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org, Greg Kroah-Hartman
	<gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org,
	linux-serial@vger.kernel.org
Message-Id: <2XFP6S.GINKQ8IKAA1W1@gmail.com>
In-Reply-To: <CAHk-=wgLZXULo7pg=nwUMFLsKNUe+1_X=Fk7+f-J0735Oir97w@mail.gmail.com>
References: <cover.1703126594.git.nabijaczleweli@nabijaczleweli.xyz>
	<4dec932dcd027aa5836d70a6d6bedd55914c84c2.1703126594.git.nabijaczleweli@nabijaczleweli.xyz>
	<6c3fc5e9-f8cf-4b42-9317-8ce9669160c2@kernel.org>
	<CAHk-=wgLZXULo7pg=nwUMFLsKNUe+1_X=Fk7+f-J0735Oir97w@mail.gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed


On Wed, Jan 3 2024 at 11:14:59 -08:00:00, Linus Torvalds 
<torvalds@linux-foundation.org> wrote:
> 
> It's some annoying SSL VPN thing that splices to pppd:
> 
>    https://lore.kernel.org/all/C8KER7U60WXE.25UFD8RE6QZQK@oguc/

I'm happy to report that that particular SSL VPN tool is no longer 
around.
And it had anyway grown a fall-back-to-read/write in case splice() 
fails.
So at least from my perspective, no objections to splice-to-tty going 
away
altogether.

> and I'd be happy to try to limit splice to tty's to maybe just the one
> case that pppd uses.

To be exact, pppd is just providing a pty with which other (now all 
extinct?)
applications can do nefarious things.

> Maybe that VPN thing already has the pty in non-blocking mode, for
> example, and we could make the tty splicing fail for any blocking op?

FWIW, the SSL VPN tool did indeed have the pty in non-blocking mode.

Oliver