From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Mark H Weaver Newsgroups: gmane.emacs.devel Subject: Re: Emacs Lisp's future Date: Tue, 07 Oct 2014 12:34:39 -0400 Message-ID: <8761fvn8io.fsf@yeeloong.lan> References: <54193A70.9020901@member.fsf.org> <87tx3tmi3t.fsf@fencepost.gnu.org> <834mvttgsf.fsf@gnu.org> <87lhp5m99w.fsf@fencepost.gnu.org> <87h9ztm5oa.fsf@fencepost.gnu.org> <87d2ahm3nw.fsf@fencepost.gnu.org> <871tqneyvl.fsf@netris.org> <87d2a54t1m.fsf@yeeloong.lan> <83lhotme1e.fsf@gnu.org> <871tql17uw.fsf@yeeloong.lan> <838uktm9gw.fsf@gnu.org> <87h9zgarvp.fsf@fencepost.gnu.org> <87mw97rjwm.fsf@yeeloong.lan> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1412700987 15153 80.91.229.3 (7 Oct 2014 16:56:27 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 7 Oct 2014 16:56:27 +0000 (UTC) Cc: David Kastrup , Richard Stallman , dmantipov@yandex.ru, emacs-devel@gnu.org, handa@gnu.org, monnier@iro.umontreal.ca, Eli Zaretskii , stephen@xemacs.org To: Andreas Schwab Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Oct 07 18:56:19 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XbY3e-00062x-L2 for ged-emacs-devel@m.gmane.org; Tue, 07 Oct 2014 18:56:18 +0200 Original-Received: from localhost ([::1]:59931 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbY3e-0000RI-CP for ged-emacs-devel@m.gmane.org; Tue, 07 Oct 2014 12:56:18 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:49147) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbY3K-0000OU-DE for emacs-devel@gnu.org; Tue, 07 Oct 2014 12:56:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XbY3E-0002HL-Rh for emacs-devel@gnu.org; Tue, 07 Oct 2014 12:55:58 -0400 Original-Received: from world.peace.net ([96.39.62.75]:58399) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XbY30-0002E6-Pv; Tue, 07 Oct 2014 12:55:39 -0400 Original-Received: from c-24-62-95-23.hsd1.ma.comcast.net ([24.62.95.23] helo=yeeloong.lan) by world.peace.net with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.72) (envelope-from ) id 1XbXj4-0005yq-7A; Tue, 07 Oct 2014 12:35:02 -0400 In-Reply-To: (Andreas Schwab's message of "Tue, 07 Oct 2014 17:31:58 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.94 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 96.39.62.75 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:175087 Archived-At: Andreas Schwab writes: > Mark H Weaver writes: > >> However, if the overlong sequence came from the network, and Emacs >> propagates it unchanged to internal subsystems[*] (e.g. via command-line >> arguments to subprocesses), that's not good. It exposes another program >> to invalid input -- a program that might not be designed for exposure to >> possible attacks via overlong encodings. > > At least it doesn't make it worse (it is unchanged from the situation if > you remove Emacs as a filter). In the case of mere "filtering", you might be right in some cases. However, the case I'm worried about is where some small piece of the hostile input is extracted and passed as an argument to another program. In cases like this it doesn't make sense to think of emacs as a "filter", and you'd never be able to "remove" it. It's like saying that a web application that passes unsanitized input to an SQL query "doesn't make it worse", and that the situation is unchanged from if you provided public access to the SQL database. Mark