Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756813Ab1DMOdz (ORCPT ); Wed, 13 Apr 2011 10:33:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7882 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756652Ab1DMOdx (ORCPT ); Wed, 13 Apr 2011 10:33:53 -0400 From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= To: Greg Kroah-Hartman Cc: Alan Cox , linux-kernel@vger.kernel.org, =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= Subject: [PATCH] Clean console safely Date: Wed, 13 Apr 2011 16:32:50 +0200 Message-Id: <1302705170-15712-2-git-send-email-ppisar@redhat.com> In-Reply-To: <1302705170-15712-1-git-send-email-ppisar@redhat.com> References: <1302705170-15712-1-git-send-email-ppisar@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1324 Lines: 37 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/