tty: ldsic: fix tty_ldisc_autoload sysctl's proc_handler

commit 635a9fca54f4f4148be1ae1c7c6bd37af80f5773 upstream.

Commit 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of
ldiscs") introduces the tty_ldisc_autoload sysctl with the wrong
proc_handler. .extra1 and .extra2 parameters are set to avoid other values
thant SYSCTL_ZERO or SYSCTL_ONE to be set but proc_dointvec do not uses
them.

This commit fixes this by using proc_dointvec_minmax instead of
proc_dointvec.

Fixes: 7c0cca7c847e ("tty: ldisc: add sysctl to prevent autoloading of ldiscs")
Cc: stable <[email protected]>
Signed-off-by: Nicolas Bouchinet <[email protected]>
Reviewed-by: Lin Feng <[email protected]>
Reviewed-by: Jiri Slaby <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: nbouchinet-anssi

drivers/tty/tty_ldisc.c

@@ -877,7 +877,7 @@ static struct ctl_table tty_table[] = {
 		.data		= &tty_ldisc_autoload,
 		.maxlen		= sizeof(tty_ldisc_autoload),
 		.mode		= 0644,
-		.proc_handler	= proc_dointvec,
+		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= &zero,
 		.extra2		= &one,
 	},