From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#19565: Emacs vulnerable to endless-data attack (minor) Date: Sun, 06 Oct 2019 20:32:28 +0300 Message-ID: <83a7ad3hlf.fsf@gnu.org> References: Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="238487"; mail-complaints-to="usenet@blaine.gmane.org" Cc: larsi@gnus.org, 19565@debbugs.gnu.org To: Stefan Kangas Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Oct 06 19:33:13 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1iHAP9-000zoE-NT for geb-bug-gnu-emacs@m.gmane.org; Sun, 06 Oct 2019 19:33:11 +0200 Original-Received: from localhost ([::1]:36033 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHAP8-0003ZT-LV for geb-bug-gnu-emacs@m.gmane.org; Sun, 06 Oct 2019 13:33:10 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:38534) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iHAP0-0003Yu-Sf for bug-gnu-emacs@gnu.org; Sun, 06 Oct 2019 13:33:03 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iHAOz-000807-VX for bug-gnu-emacs@gnu.org; Sun, 06 Oct 2019 13:33:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:37968) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iHAOz-000802-SN for bug-gnu-emacs@gnu.org; Sun, 06 Oct 2019 13:33:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1iHAOz-000889-Ni for bug-gnu-emacs@gnu.org; Sun, 06 Oct 2019 13:33:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 06 Oct 2019 17:33:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 19565 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: security Original-Received: via spool by 19565-submit@debbugs.gnu.org id=B19565.157038316831231 (code B ref 19565); Sun, 06 Oct 2019 17:33:01 +0000 Original-Received: (at 19565) by debbugs.gnu.org; 6 Oct 2019 17:32:48 +0000 Original-Received: from localhost ([127.0.0.1]:46789 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1iHAOm-00087d-72 for submit@debbugs.gnu.org; Sun, 06 Oct 2019 13:32:48 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:57677) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1iHAOk-00087M-6I for 19565@debbugs.gnu.org; Sun, 06 Oct 2019 13:32:46 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:60541) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1iHAOe-0007ob-Vz; Sun, 06 Oct 2019 13:32:41 -0400 Original-Received: from [176.228.60.248] (port=1761 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1iHAOd-00052N-Ti; Sun, 06 Oct 2019 13:32:40 -0400 In-reply-to: (message from Stefan Kangas on Sun, 6 Oct 2019 05:13:27 +0200) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:168439 Archived-At: > From: Stefan Kangas > Date: Sun, 6 Oct 2019 05:13:27 +0200 > Cc: 19565@debbugs.gnu.org > > I think this affects more than just package.el. AFAICT, anywhere we > use the url library, an endless data attack can get Emacs to fill up > all available memory (wasting also bandwidth resources, of course). At which point the system will kill the Emacs process. Why is that a problem we need to work, given that we already have at least some protection against stack overflows and running out of memory? > For example, a new keyword argument :max-size, which would make it > stop after having reached that many bytes. The Gnu Coding Standards frown on having arbitrary limits in a program. So this could only work if we had some reasonable way of computing a limit that is not arbitrary.