From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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> In-Reply-To: <20131202191248.517975703@linuxfoundation.org> References: <20131202191248.517975703@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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);