From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758413AbbCDGOc (ORCPT ); Wed, 4 Mar 2015 01:14:32 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:41855 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758342AbbCDGO1 (ORCPT ); Wed, 4 Mar 2015 01:14:27 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , Howard Chu , One Thousand Gnomes , Jiri Slaby , Peter Hurley Subject: [PATCH 3.10 32/53] tty: Prevent untrappable signals from malicious program Date: Tue, 3 Mar 2015 22:06:35 -0800 Message-Id: <20150304054615.418498816@linuxfoundation.org> X-Mailer: git-send-email 2.3.1 In-Reply-To: <20150304054609.869052846@linuxfoundation.org> References: <20150304054609.869052846@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Hurley commit 37480a05685ed5b8e1b9bf5e5c53b5810258b149 upstream. Commit 26df6d13406d1a5 ("tty: Add EXTPROC support for LINEMODE") allows a process which has opened a pty master to send _any_ signal to the process group of the pty slave. Although potentially exploitable by a malicious program running a setuid program on a pty slave, it's unknown if this exploit currently exists. Limit to signals actually used. Cc: Theodore Ts'o Cc: Howard Chu Cc: One Thousand Gnomes Cc: Jiri Slaby Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/pty.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -215,6 +215,9 @@ static int pty_signal(struct tty_struct unsigned long flags; struct pid *pgrp; + if (sig != SIGINT && sig != SIGQUIT && sig != SIGTSTP) + return -EINVAL; + if (tty->link) { spin_lock_irqsave(&tty->link->ctrl_lock, flags); pgrp = get_pid(tty->link->pgrp);