From 32b2921e6a7461fe63b71217067a6cf4bddb132f Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Fri, 14 Oct 2016 15:18:28 +0200 Subject: [PATCH] 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 CC: David Rientjes Cc: One Thousand Gnomes Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Peter Hurley Cc: linux-kernel@vger.kernel.org Cc: syzkaller@googlegroups.com Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index ae203c2cd15a..26cda08bc611 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -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; -- 2.20.1