From f8df13e0a901fe55631fed66562369b4dba40f8b Mon Sep 17 00:00:00 2001 From: =?utf8?q?Petr=20P=C3=ADsa=C5=99?= Date: Fri, 15 Apr 2011 10:08:08 +0200 Subject: [PATCH] tty: Clean console safely MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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. Signed-off-by: Petr Písař Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/vt.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index a48da2063060..b3915b7ad3e2 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -1193,6 +1193,13 @@ 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); + /* fall through */ case 2: /* erase whole display */ count = vc->vc_cols * vc->vc_rows; start = (unsigned short *)vc->vc_origin; -- 2.20.1