From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <952dbd2b992f9f807f09fb725e0fadd7@vitanuova.com> To: 9fans@cse.psu.edu Subject: Re: [9fans] useful language extension, or no? From: forsyth@vitanuova.com MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="upas-rtbtqyexyvkfadcsizalwwroof" Date: Thu, 18 Jul 2002 16:02:25 +0100 Topicbox-Message-UUID: d0d3f2fe-eaca-11e9-9e20-41e7f4b1d025 This is a multi-part message in MIME format. --upas-rtbtqyexyvkfadcsizalwwroof Content-Disposition: inline Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit actually, the thing i don't understand is why nested procedures required putting code on the stack. i've implemented them a few times, even with closures, and i didn't need to do that. where did i do wrong? perhaps it was just a display of technical prowess, or does gcc also not do that, really. --upas-rtbtqyexyvkfadcsizalwwroof Content-Type: message/rfc822 Content-Disposition: inline Return-Path: <9fans-admin@cse.psu.edu> Received: from punt-2.mail.demon.net by mailstore for forsyth@vitanuova.com id 1027002823:20:13866:54; Thu, 18 Jul 2002 14:33:43 GMT Received: from psuvax1.cse.psu.edu ([130.203.4.6]) by punt-2.mail.demon.net id aa2120795; 18 Jul 2002 14:33 GMT Received: from psuvax1.cse.psu.edu (psuvax1.cse.psu.edu [130.203.8.6]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id 4476A19A7D; Thu, 18 Jul 2002 10:33:23 -0400 (EDT) Delivered-To: 9fans@cse.psu.edu Received: from mercury.bath.ac.uk (mercury.bath.ac.uk [138.38.32.81]) by mail.cse.psu.edu (CSE Mail Server) with ESMTP id A4346199ED for <9fans@cse.psu.edu>; Thu, 18 Jul 2002 10:32:27 -0400 (EDT) Received: from news by mercury.bath.ac.uk with local (Exim 3.12 #1) id 17VC9c-0006nx-00 for 9fans@cse.psu.edu; Thu, 18 Jul 2002 15:21:16 +0100 Received: from GATEWAY by bath.ac.uk with netnews for 9fans@cse.psu.edu (9fans@cse.psu.edu) To: 9fans@cse.psu.edu From: "Douglas A. Gwyn" Message-ID: <3D36CB17.D4FEC4C0@null.net> Organization: U.S. Army Research Laboratory Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit References: , <20020718121930.K14964@cackle.proxima.alt.za> Subject: Re: [9fans] useful language extension, or no? Sender: 9fans-admin@cse.psu.edu Errors-To: 9fans-admin@cse.psu.edu X-BeenThere: 9fans@cse.psu.edu X-Mailman-Version: 2.0.11 Precedence: bulk Reply-To: 9fans@cse.psu.edu List-Id: Fans of the OS Plan 9 from Bell Labs <9fans.cse.psu.edu> List-Archive: Date: Thu, 18 Jul 2002 14:21:07 GMT Lucio De Re wrote: > The usual buffer overflow problem: override the stack limits, wreck > the return address, execute the remainder (by returning to it). But that is independent of whether the original program generated code on the stack. It's merely a matter of whether the stack lies in an address space compatible with instruction space. On a split I/D-space system, or one where pages do support X bits, code cannot run on the stack. Anyway, buffer overruns would be a security problem anyway, even if one could not add code, because state variables can be changed in unplanned ways. One of the early such exploits merely set the "password was valid" flag. --upas-rtbtqyexyvkfadcsizalwwroof--