lkml.org 
[lkml]   [2011]   [Apr]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] Clean console safely
Date
Traditional \E[2J sequence erases console display but scroll-back
buffer and underlying device (frame) buffer keep data that can be
accessed by scrolling console back.

This patch introduce new \E[J parameter 3 that allows to scramble
scroll-back buffer explicitly. Session locking programs (screen,
vlock) can use it to prevent attacker to browse locked console
history.
---
drivers/tty/vt/vt.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 4bea1ef..fe96a1f 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1197,6 +1197,12 @@ static void csi_J(struct vc_data *vc, int vpar)
vc->vc_x + 1);
}
break;
+ case 3: /* erase scroll-back buffer (and whole display) */
+ 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);
case 2: /* erase whole display */
count = vc->vc_cols * vc->vc_rows;
start = (unsigned short *)vc->vc_origin;
--
1.7.4.4


\
 
 \ /
  Last update: 2011-04-13 16:37    [W:0.038 / U:2.668 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site