Patch "tty: limit terminal size to 4M chars" has been added to the 4.8-stable tree

Patch "tty: limit terminal size to 4M chars" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    tty: limit terminal size to 4M chars

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tty-limit-terminal-size-to-4m-chars.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 32b2921e6a7461fe63b71217067a6cf4bddb132f Mon Sep 17 00:00:00 2001
From: Dmitry Vyukov <dvyukov@google.com>
Date: Fri, 14 Oct 2016 15:18:28 +0200
Subject: tty: limit terminal size to 4M chars

From: Dmitry Vyukov <dvyukov@google.com>

commit 32b2921e6a7461fe63b71217067a6cf4bddb132f upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/tty/vt/vt.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -870,6 +870,8 @@ static int vc_do_resize(struct tty_struc
 	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;


Patches currently in stable-queue which might be from dvyukov@google.com are

queue-4.8/tty-limit-terminal-size-to-4m-chars.patch
queue-4.8/vt-clear-selection-before-resizing.patch