Date: Mon, 20 Jul 1998 22:26:13 +0400 From: Alexandre Snarskii <snar@paranoia.ru> To: Brett Glass <brett@lariat.org>, Alexandre Snarskii <snar@paranoia.ru> Cc: security@FreeBSD.ORG Subject: Re: The 99,999-bug question: Why can you execute from the stack? Message-ID: <19980720222613.37562@nevalink.ru> In-Reply-To: <199807201714.LAA19993@lariat.lariat.org>; from Brett Glass on Mon, Jul 20, 1998 at 11:14:33AM -0600 References: <199807200148.TAA07794@harmony.village.org> <199807200102.SAA07953@bubba.whistle.com> <199807200148.TAA07794@harmony.village.org> <19980720152932.42290@nevalink.ru> <199807201714.LAA19993@lariat.lariat.org>
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On Mon, Jul 20, 1998 at 11:14:33AM -0600, Brett Glass wrote: > Waitaminnit. Intel installed, IN THE x86 CHIPS WE ARE NOW USING, special > hardware designed to guard against these exploits. The mechanisms > they designed are called "segments" and "call gates" (among other > things). And what do we do? We turn it off. In fact, Intel sees > so few people using these vital features that it doesn't bother > to speed them up in new CPU models, as they do other parts of > the chip. > > In short, the hackers who want slightly more convenient "flat" > address spaces have contributed in devastating ways to the problems > we have now. Can you release kernel patches to realise hardware-level protection ? ( I'm not an experienced kernel programer, and have no enough time to learn kernel internals, sorry :( ) I know, that my solution is rather 'fast and dirty hack', but it works. And i don't see any another solution for stack smashing prevention for FreeBSD now. PS: btw, non-executable stack don't protect against return-into-libc attack ( as demonstrated by Rafal Wojtczuk in bugtraq against Solar Designer's patch ). -- Alexandre Snarskii the source code is included To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe security" in the body of the message
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