From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [PATCH] tty: Only hangup once Date: Tue, 19 Nov 2013 09:40:32 -0800 Message-ID: <20131119174032.GB22604@kroah.com> References: <1375293945-4087-1-git-send-email-peter@hurleysoftware.com> <20131117203850.46df2124@tormoz-pc> <20131118134211.17861db3@alan.etchedpixels.co.uk> <528A5043.6030901@hurleysoftware.com> <528A797B.6020807@hurleysoftware.com> <20131119000923.5ca40e51@tormoz-pc> <528B6BB3.7020303@hurleysoftware.com> <20131119201952.2d63b8ce@tormoz-pc> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20131119201952.2d63b8ce@tormoz-pc> Sender: linux-kernel-owner@vger.kernel.org To: Heorhi Valakhanovich Cc: Peter Hurley , One Thousand Gnomes , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org List-Id: linux-serial@vger.kernel.org On Tue, Nov 19, 2013 at 08:19:52PM +0300, Heorhi Valakhanovich wrote: > On Tue, 19 Nov 2013 08:46:27 -0500 > Peter Hurley wrote: > > > Would you please test the patch below and confirm the fix? > > > > --->%--- > > Subject: [PATCH] tty: Reset hupped state on open > > > > A common security idiom is to hangup the current tty (via vhangup()) > > after forking but before execing a root shell. This hangs up any > > existing opens which other processes may have and ensures subsequent > > opens have the necessary permissions to open the root shell tty/pty. > > > > Reset the TTY_HUPPED state after the driver has successfully > > returned the opened tty (perform the reset while the tty is locked > > to avoid racing with concurrent hangups). > > > > Reported-by: Heorhi Valakhanovich > > Signed-off-by: Peter Hurley > > --- > > drivers/tty/tty_io.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c > > index 3a1a01a..c74a00a 100644 > > --- a/drivers/tty/tty_io.c > > +++ b/drivers/tty/tty_io.c > > @@ -2086,6 +2086,7 @@ retry_open: > > filp->f_op = &tty_fops; > > goto retry_open; > > } > > + clear_bit(TTY_HUPPED, &tty->flags); > > tty_unlock(tty); > > > > > > It looks like this patch works. It solves my problem. Thanks. > Will wait for such fix in mainline. I'll queue this up after 3.13-rc1 is out. It should be backported to 3.12, and any other kernels? thanks, greg k-h