Date: Sat, 27 Jun 1998 00:13:42 -0400 (EDT) From: Patrick McAndrew <pfm@slack.net> To: jtb <jtb@pubnix.org> Cc: Wojciech Sobczuk <sopel@hood.1lo.lublin.pl>, fpscha@schapachnik.com.ar, Niall Smart <njs3@doc.ic.ac.uk>, ncb05@uow.edu.au, security@FreeBSD.ORG Subject: Re: non-executable stack? Message-ID: <Pine.NEB.3.96.980627001158.27630A-100000@brooklyn.slack.net> In-Reply-To: <Pine.SOL.3.96.980626131059.442A-100000@pubnix.org>
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On Fri, 26 Jun 1998, jtb wrote: > Actually, Brian Matthews brought this idea up to me last fall, and the > more I've been thinking about it lately, why not just deny a handful of > ctrl-char's that a buffer overflow needs, i.e. 0x90, 0xff, etc. I'd have > to say there is a minimal number of ctrl-char's we can disallow to stop > your average script kiddie from sending shellcode into a process via > cmdline or environment arguments. This method won't really protect > against attacks involving sscanf()'ing data from files ala the Vixie Cron > bug for RH 4.x, but security will definitely be improved with minimal > loses funcionality-wise. Let me know what you guys think. All replies > are welcomed, critical or not. Why bother? Just practice good security programming and check bounds. It would be much easier to fix a getc() call than to write an entire function that checks for certain control characters that were passed.. Rember, "keep it simpe stupid" :) Pat To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe security" in the body of the message
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