From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755525Ab2ADN0n (ORCPT ); Wed, 4 Jan 2012 08:26:43 -0500 Received: from mail-ee0-f46.google.com ([74.125.83.46]:54782 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755234Ab2ADN0k (ORCPT ); Wed, 4 Jan 2012 08:26:40 -0500 Message-ID: <4F045386.3050706@openvz.org> Date: Wed, 04 Jan 2012 17:26:30 +0400 From: Konstantin Khlebnikov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.19) Gecko/20111108 Iceape/2.0.14 MIME-Version: 1.0 To: Linus Torvalds CC: Greg Kroah-Hartman , Alan Cox , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] tty: cleanup prohibition of direct opening for unix98 pty master References: <20120102172231.11476.57711.stgit@zurg> <20120103085110.17283.60539.stgit@zurg> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > Looks ok as far as I can tell, and does indeed clean things up. I > assume somebody tested the case that we used to have issues with? Yes of course I tested it. > > Linus > > On Tue, Jan 3, 2012 at 12:51 AM, Konstantin Khlebnikov > wrote: >> cleanup hack added in v2.6.27-3203-g15582d3 >> >> comment from that patch: >> >> : pty: If the administrator creates a device for a ptmx slave we should not error >> : >> : The open path for ptmx slaves is via the ptmx device. Opening them any >> : other way is not allowed. Vegard Nossum found that previously this was not >> : the case and mknod foo c 128 42; cat foo would produce nasty diagnostics >> : >> : Signed-off-by: Alan Cox >> : Signed-off-by: Linus Torvalds >> >> devpts_get_tty() returns non-null only for inodes on devpts, but there is no >> inodes for master-devices, /dev/ptmx (/dev/pts/ptmx) is the only way to open them. >> Thus we can completely forbid lookup for master-devices and eliminate that hack in >> tty_init_dev() because tty_open() will get EIO from tty_driver_lookup_tty(). >> >> Signed-off-by: Konstantin Khlebnikov