From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Preview: portable dumper Date: Sat, 3 Dec 2016 13:54:20 -0800 Organization: UCLA Computer Science Department Message-ID: <38de11c4-9236-f6e4-b8ce-31a2e7f2f6c2@cs.ucla.edu> References: <047a67ec-9e29-7e4e-0fb0-24c3e59b5886@dancol.org> <9b6a0571-b2ae-a5dd-a643-3595e8f71cd6@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1480802111 9633 195.159.176.226 (3 Dec 2016 21:55:11 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 3 Dec 2016 21:55:11 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 Cc: emacs-devel@gnu.org To: rms@gnu.org, Daniel Colascione Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Dec 03 22:55:07 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cDIGw-00011d-O0 for ged-emacs-devel@m.gmane.org; Sat, 03 Dec 2016 22:55:06 +0100 Original-Received: from localhost ([::1]:52621 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cDIGv-0003TH-Ph for ged-emacs-devel@m.gmane.org; Sat, 03 Dec 2016 16:55:05 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:42542) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cDIGJ-0003T1-4e for emacs-devel@gnu.org; Sat, 03 Dec 2016 16:54:27 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cDIGG-0003HB-3r for emacs-devel@gnu.org; Sat, 03 Dec 2016 16:54:27 -0500 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:59096) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cDIGF-0003GI-UO; Sat, 03 Dec 2016 16:54:24 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 4814116006A; Sat, 3 Dec 2016 13:54:21 -0800 (PST) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id nV9NBoV2WM0y; Sat, 3 Dec 2016 13:54:20 -0800 (PST) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 953F5160073; Sat, 3 Dec 2016 13:54:20 -0800 (PST) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id TRiKp8JgYR7k; Sat, 3 Dec 2016 13:54:20 -0800 (PST) Original-Received: from [192.168.1.9] (unknown [47.153.178.162]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id 75AE216006A; Sat, 3 Dec 2016 13:54:20 -0800 (PST) In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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" Xref: news.gmane.org gmane.emacs.devel:210003 Archived-At: Richard Stallman wrote: > What Emacs does with the contents of an incoming packet is mainly > to turn it into Lisp objects and make that available at Lisp level. > That means not much opportunity for such a bug to occur. Sure, but incoming packets are not random and attackers can design packet= s to=20 exploit Emacs bugs. So any opportunity whatsoever in Lisp conversion is m= ore of=20 concern than it would be for more-typical pointer bugs. And as Daniel men= tioned,=20 attackers will likely focus on the occasions when Emacs converts packet c= ontents=20 to non-Lisp objects. I have been looking into improving checking in this area, by using the=20 -fcheck-pointer-bounds option introduced in GCC 5 and supported by some n= ewer=20 CPUs. Although -fcheck-pointer-bounds should help, it won't be perfect an= d it=20 will be disabled by default due to its performance cost.