From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756470Ab3LBTxm (ORCPT ); Mon, 2 Dec 2013 14:53:42 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:39379 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754742Ab3LBTSO (ORCPT ); Mon, 2 Dec 2013 14:18:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Heorhi Valakhanovich , Peter Hurley Subject: [PATCH 3.12 118/212] tty: Reset hupped state on open Date: Mon, 2 Dec 2013 11:15:09 -0800 Message-Id: <20131202191300.339003023@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.3.gca3854a In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> User-Agent: quilt/0.60-8.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Hurley commit d4855e1fc03c2bb32dd64badf51cec5a2a26ab2a upstream. 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 Tested-by: Heorhi Valakhanovich Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 1 + 1 file changed, 1 insertion(+) --- 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);