[PATCH] tty: Only allow slave pty as controlling tty

From: Peter Hurley
Date: Sun Nov 08 2015 - 09:06:53 EST


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@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/tty_io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 9fa5a4f..2f9c1c6 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2862,7 +2862,7 @@ 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:
--
2.6.3

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