Commit 32b2921e authored Oct 14, 2016 by Dmitry Vyukov Committed by Greg Kroah-Hartman Oct 27, 2016

tty: limit terminal size to 4M chars



Size of kmalloc() in vc_do_resize() is controlled by user.
Too large kmalloc() size triggers WARNING message on console.
Put a reasonable upper bound on terminal size to prevent WARNINGs.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
CC: David Rientjes <rientjes@google.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Cc: syzkaller@googlegroups.com
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d704b2d3

drivers/tty/vt/vt.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -870,6 +870,8 @@ static int vc_do_resize(struct tty_struct tty, struct vc_data vc,
		if (new_cols == vc->vc_cols && new_rows == vc->vc_rows)
		return 0;

		if (new_screen_size > (4 << 20))
		return -EINVAL;
		newscreen = kmalloc(new_screen_size, GFP_USER);
		if (!newscreen)
		return -ENOMEM;