Date: Sat, 29 Jun 2002 18:55:54 -0400 From: Jake Burkholder <jake@locore.ca> To: Terry Lambert <tlambert2@mindspring.com> Cc: arch@FreeBSD.ORG Subject: Re: Time to make the stack non-executable? Message-ID: <20020629185554.I71376@locore.ca> In-Reply-To: <3D1E3126.C96FFAA5@mindspring.com>; from tlambert2@mindspring.com on Sat, Jun 29, 2002 at 03:13:58PM -0700 References: <3D1E28ED.B67A5271@FreeBSD.org> <3D1E3126.C96FFAA5@mindspring.com>
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Apparently, On Sat, Jun 29, 2002 at 03:13:58PM -0700, Terry Lambert said words to the effect of; > Doug Barton wrote: > > Subject: We're famous > >http://story.news.yahoo.com/news?tmpl=story&ncid=70&e=2&cid=70&u=/cn/20020629/tc_cn/940585 > > > Sean Eric Fagan and I discussed this several years ago, and we > discussed it again the other day, before this attack hit. It > looks like it's an idea whose time has come. > > We've identified a number of issues that might make doing this > problematic, and on which there needs to be feedback: > > o Java; specifically, JITs may rely on an executable > stack. Neither of us knows if this is true, for > sure. > > o FORTH? Same question. > > o Signals > > o Julian's new threads patches > > o Multiple architecture support > > Right now, SEF points out (and I concur) that the only portion > of the system that seems to care about having an executable stack > is the signal trampoline. I would imagine that the trampoline > for the user space threads scheduler for KSE based threading will > (does) have the same problem. > > For signals, this is easy: copy SVR4, and modify the signal > functions to pass in a return address, then disable the execute > bits on stack pages and see whose head blows up. > > Frankly, I'm very surprised to discover that OpenBSD has not > already done this. > > Opinions? Patches from people who know and love the signals > facility on Alpha, SPARC64, PPC, etc.? The sparc64 signal trampoline is already in libc, I'm running a kernel which maps the stack non-executable locally. Jake To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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