Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4

Path	csiph.com!weretis.net!feeder4.news.weretis.net!news.unit0.net!news.panservice.it!bofh.it!news.nic.it!robomod
From	Greg KH <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4
Date	Wed, 31 May 2017 13:20:02 +0200
Message-ID	<tN9Ps-424-17@gated-at.bofh.it> (permalink)
References	<tvPtM-5kd-25@gated-at.bofh.it> <tvROV-6SF-1@gated-at.bofh.it> <tw61z-7Ud-19@gated-at.bofh.it> <tw8G5-14T-11@gated-at.bofh.it> <tCJ0e-ID-11@gated-at.bofh.it> <tCNZT-3O5-3@gated-at.bofh.it> <tD1gw-5a8-51@gated-at.bofh.it> <tMLDt-5ux-43@gated-at.bofh.it> <tMO8h-7b8-9@gated-at.bofh.it> <tN7kD-2mN-41@gated-at.bofh.it>
X-Original-To	Dmitry Vyukov <dvyukov@google.com>
MIME-Version	1.0
Content-Type	text/plain; charset=us-ascii
Content-Disposition	inline
User-Agent	Mutt/1.8.2 (2017-04-18)
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	25
Organization	linux.* mail to news gateway
X-Original-Cc	Alan Cox <gnomes@lxorguk.ukuu.org.uk>, Vegard Nossum <vegard.nossum@gmail.com>, Linus Torvalds <torvalds@linux-foundation.org>, Jiri Slaby <jslaby@suse.cz>, Andrew Morton <akpm@linux-foundation.org>, LKML <linux-kernel@vger.kernel.org>, linux-serial <linux-serial@vger.kernel.org>
X-Original-Date	Wed, 31 May 2017 20:16:12 +0900
X-Original-Message-ID	<20170531111612.GA6332@kroah.com>
X-Original-References	<CA+55aFwgiAmy4Gw4RosbNVBJmOG-WQoZKOd76Ziuqx5CzPFMZQ@mail.gmail.com> <20170413183403.GA16022@kroah.com> <CAOMGZ=G9t7ih=ydr=fkKn6cbgu5-qbdQs7XChmn=d598H95QVA@mail.gmail.com> <20170414123029.GA17217@kroah.com> <CACT4Y+acU1xTZEo+oeBvZL__c12bzcSPa0CBfDiw4j7+CUjfDg@mail.gmail.com> <CAOMGZ=GJah0GNXzscGGkYgScbZaeSM_TpxmrLZuxhrqWmBX9BQ@mail.gmail.com> <20170503120101.GA21119@kroah.com> <CACT4Y+arELXuPr7psYFETt6NrDNgeS=tP=jGhP4a0_C_8Fa=LA@mail.gmail.com> <20170530130905.382487d5@alans-desktop> <CACT4Y+aoRRao41hGpVkO+qVk9TB5ZSPiRpQxp7H9EN+RqW-1-Q@mail.gmail.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1654136

Show key headers only | View raw

On Wed, May 31, 2017 at 10:39:23AM +0200, Dmitry Vyukov wrote:
> On Tue, May 30, 2017 at 2:09 PM, Alan Cox <gnomes@lxorguk.ukuu.org.uk> wrote:
> >> >> I'll think about possible solutions, but I have no prior experience
> >> >> with the tty code. In the meantime syzkaller also hit a couple of
> >> >> other fun tty/pty bugs including a write/ioctl race that results in
> >> >> buffer overflow :-/
> >
> > There are several of those, including some of that have been documented
> > for years but nobody ever volunteered to fix - in particular all the
> > interfaces that push characters to the tty other than via the normal
> > interrupt receive path are dodgy (console selection in particular)
> >
> > The original tty model btw was that setting the ldisc to n_tty cannot
> > fail, and the structure allocated was smaller than a page size so was
> > safe.
> >
> > The simple way to fix it is to restore that behaviour by adding a 'null'
> > ldisc that we can fail to instead of N_TTY since the N_TTY failback path
> > is long broken.
> 
> Greg, what do you think about this patch? Are you ready to accept
> something like this?
> Definitely shorter than changing all drivers.

Yes, it looks reasonable to me.

Thread

Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Dmitry Vyukov <dvyukov@google.com> - 2017-05-30 11:30 +0200
  Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-30 14:10 +0200
    Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Dmitry Vyukov <dvyukov@google.com> - 2017-05-31 10:40 +0200
      Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Greg KH <gregkh@linuxfoundation.org> - 2017-05-31 13:20 +0200
        Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Alan Cox <gnomes@lxorguk.ukuu.org.uk> - 2017-05-31 17:10 +0200
          Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Dmitry Vyukov <dvyukov@google.com> - 2017-06-01 14:10 +0200
            Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Greg KH <gregkh@linuxfoundation.org> - 2017-06-02 02:10 +0200

csiph-web