From owner-freebsd-security@FreeBSD.ORG Fri Apr 22 12:37:23 2005 Return-Path: Delivered-To: freebsd-security@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id CACE716A4CE for ; Fri, 22 Apr 2005 12:37:23 +0000 (GMT) Received: from mail24.sea5.speakeasy.net (mail24.sea5.speakeasy.net [69.17.117.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7AC5743D31 for ; Fri, 22 Apr 2005 12:37:23 +0000 (GMT) (envelope-from freebsd-security-local@be-well.ilk.org) Received: (qmail 7029 invoked from network); 22 Apr 2005 12:37:21 -0000 Received: from dsl092-078-145.bos1.dsl.speakeasy.net (HELO be-well.ilk.org) ([66.92.78.145]) (envelope-sender ) by mail24.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 22 Apr 2005 12:37:21 -0000 Received: by be-well.ilk.org (Postfix, from userid 1147) id B7D2854; Fri, 22 Apr 2005 08:37:20 -0400 (EDT) Sender: lowell@be-well.ilk.org To: jesper@hackunite.net References: <42686A29.7090900@hackunite.net> From: Lowell Gilbert Date: 22 Apr 2005 08:37:20 -0400 In-Reply-To: <42686A29.7090900@hackunite.net> Message-ID: <441x93vvgf.fsf@be-well.ilk.org> Lines: 16 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii cc: freebsd-security@freebsd.org Subject: Re: Information disclosure? X-BeenThere: freebsd-security@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Security issues [members-only posting] List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Apr 2005 12:37:23 -0000 Jesper Wallin writes: > For some reason, I thought little about the "clear" command > today.. Let's say a privileged user (root) logs on, edit a sensitive > file (e.g, a file containing a password, running vipw, etc) .. then > runs clear and logout. Then anyone can press the scroll-lock command, > scroll back up and read the sensitive information.. Isn't "clear" ment > to clear the backbuffer instead of printing a full screen of returns? That might have made sense, but it's never been the case. clear(1) is meant and documented to execute the "clear_screen" termcap sequence. If you want to clear the history buffer, just use vidcontrol(1). It has options to clear or change the size of the history buffer, and it is already specific to syscons(4), so it doesn't need to be as general as termcap(5).