From: Petr Písař <petr.pisar@atlas.cz>
Date: Thu, 6 Feb 2014 20:01:23 +0000 (+0100)
Subject: vt: Fix secure clear screen
X-Git-Tag: firefly_0821_release~3679^2~2798
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=27f0831c1aedad09238f173550919ac7f809e4fa;p=firefly-linux-kernel-4.4.55.git

vt: Fix secure clear screen

commit 0930b0950a8996aa88b0d2ba4bb2bab27cc36bc7 upstream.

\E[3J console code (secure clear screen) needs to update_screen(vc)
in order to write-through blanks into off-screen video memory.

This has been removed accidentally in 3.6 by:

commit 81732c3b2fede049a692e58a7ceabb6d18ffb18c
Author: Jean-François Moine <moinejf@free.fr>
Date:   Thu Sep 6 19:24:13 2012 +0200

    tty vt: Fix line garbage in virtual console on command line edition

Signed-off-by: Petr Písař <petr.pisar@atlas.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 740202d8a5c4..0d1b3757cfb6 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1164,6 +1164,8 @@ static void csi_J(struct vc_data *vc, int vpar)
 			scr_memsetw(vc->vc_screenbuf, vc->vc_video_erase_char,
 				    vc->vc_screenbuf_size >> 1);
 			set_origin(vc);
+			if (CON_IS_VISIBLE(vc))
+				update_screen(vc);
 			/* fall through */
 		case 2: /* erase whole display */
 			count = vc->vc_cols * vc->vc_rows;