Messages in this thread | | | Subject | Re: Non-Executable Stack Patch | Date | Wed, 04 Jun 1997 09:03:12 -0400 | From | Christopher Blizzard <> |
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In message <9706040136.AA11175@dcl.MIT.EDU>, "Theodore Y. Ts'o" writes: : Date: Wed, 04 Jun 1997 02:50:04 +0300 : From: Andi Gutmans <andi@vipe.technion.ac.il> : : Well with a non-executable stack most security conscious system : administrators will sleep better :) I can guarantee that. (Not too much : better as holes always exist but quite a lot). : :The advantage of the patch is that it will stop the current set of :attacks that take the form of "find buffer overrun in a program", :followed by "apply standard toolkit to exploit buffer overrun by putting :executable code on the stack". : :The disadvantage of the patch is that after we apply, within a few :months we will see a new toolkit of the form "corrupt the stack to point :the return address into someplace entertaining in libc --- like right :before an an execl call in the implementation of popen()." : :The danger is people thinking that with this patch, they don't need to :worry about finding and fixing buffer overrun bugs in their code.... : : - Ted :
This was hashed over quite a bit on the bugtraq list. People had a lot of reservations about using the non executable stack because of glibc. Apparently, glibc uses trampolines which require an executable stack. libc 5 apparently doesn't use them which is why people have been able to get away with using this patch up until now.
--Chris
------------ Christopher Blizzard AppliedTheory Communications, Inc. http://odin.appliedtheory.com/ blizzard@appliedtheory.com ------------
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