tty: ldisc: add sysctl to prevent autoloading of ldiscs
commit 7c0cca7c847e6e019d67b7d793efbbe3b947d004 upstream.
By default, the kernel will automatically load the module of any line
dicipline that is asked for. As this sometimes isn't the safest thing
to do, provide a sysctl to disable this feature.
By default, we set this to 'y' as that is the historical way that Linux
has worked, and we do not want to break working systems. But in the
future, perhaps this can default to 'n' to prevent this functionality.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 19fe1e8..15e0116 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -520,6 +520,8 @@
tty_kref_put(tty);
}
+extern void tty_sysctl_init(void);
+
/**
* proc_set_tty - set the controlling terminal
*
@@ -3705,6 +3707,7 @@
*/
int __init tty_init(void)
{
+ tty_sysctl_init();
cdev_init(&tty_cdev, &tty_fops);
if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) ||
register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0)