From: Peter Hurley <peter@hurleysoftware.com>
Date: Sun, 8 Nov 2015 14:06:05 +0000 (-0500)
Subject: tty: Only allow slave pty as controlling tty
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d1d3a0f7448fe038ce7e94e2c281dcd2f91b23c6;p=linux-beck.git

tty: Only allow slave pty as controlling tty

A master pty should never be a controlling tty in Linux; if the
master pty is specified to ioctl(TIOCSCTTY), silently substitute the slave
pty as the controlling tty.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index f38ae01c3917..892c92354745 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2866,7 +2866,7 @@ long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		no_tty();
 		return 0;
 	case TIOCSCTTY:
-		return tiocsctty(tty, file, arg);
+		return tiocsctty(real_tty, file, arg);
 	case TIOCGPGRP:
 		return tiocgpgrp(tty, real_tty, p);
 	case TIOCSPGRP: