Date: Mon, 20 Jul 1998 14:30:33 -0700 From: Don Lewis <Don.Lewis@tsc.tdk.com> To: Alexandre Snarskii <snar@paranoia.ru>, Warner Losh <imp@village.org>, Archie Cobbs <archie@whistle.com> Cc: Brett Glass <brett@lariat.org>, security@FreeBSD.ORG Subject: Re: The 99,999-bug question: Why can you execute from the stack? Message-ID: <199807202130.OAA27539@salsa.gv.tsc.tdk.com> In-Reply-To: Alexandre Snarskii <snar@paranoia.ru> "Re: The 99,999-bug question: Why can you execute from the stack?" (Jul 20, 3:29pm)
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On Jul 20, 3:29pm, Alexandre Snarskii wrote: } Subject: Re: The 99,999-bug question: Why can you execute from the stack? } On Sun, Jul 19, 1998 at 07:48:30PM -0600, Warner Losh wrote: } > Another high cost option would be to have a purify/checker-like } > functionality compiled into everything and cause a segv or some other } > generally fatal signal. This would solve all the overflows, but again } > at a huge price. } } At huge computing price. Measured in seconds, spent by processor } to perform needed computing. It may be worse than that. In a desparate attempt to track down a bug in BIND, I recompiled it with the bounds checking version of gcc. On a fairly zippy machine, it took about half an hour to load a few zones with a total of a few hundred hosts. Under light query load it was gobbling about 30% of the CPU. In the situations where I've used code compiled this way, it seems to average about a factor of 20 more expensive in terms of CPU usage. If this is acceptable to you, feel free to get the GCC patches and recompile userland (or at least those pieces that are compatible with the bounds checker). See <http://www-dse.doc.ic.ac.uk/~rj3/bounds-checking.html>. --- Truck To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe security" in the body of the message
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