[PATCH 3.11 106/121] vt: Fix secure clear screen

From: Luis Henriques
Date: Fri Feb 21 2014 - 07:57:37 EST


3.11.10.5 -stable review patch. If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <petr.pisar@xxxxxxxx>

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-FranÃois Moine <moinejf@xxxxxxx>
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 PÃsaÅ <petr.pisar@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
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 c677829..7a35647 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;
--
1.9.0

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