Date: Mon, 17 Feb 1997 13:13:24 +1030 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: cmott@srv.net (Charles Mott) Cc: freebsd-chat@FreeBSD.ORG Subject: Re: Countering stack overflow Message-ID: <199702170243.NAA07044@genesis.atrad.adelaide.edu.au> In-Reply-To: <Pine.BSF.3.91.970216191027.1528A-100000@darkstar> from Charles Mott at "Feb 16, 97 07:22:31 pm"
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Charles Mott stands accused of saying: > What I have noticed running test programs is that the top of the stack > always appears to be at or near 0xffffffff. I am interested in generating > an experimental kernel patch (for 2.1.0-R) which would randomly change the > top stack address over a range of 0x4fffffff 0xffffffff when a a new > process (not a fork) is started. > > My guess is that this will practically shut down any stack overflow > attacks which gain root privilege. They may still cause crashes or > process termination, though. > > Please advise if there is a conceptual error in what I want to do. I have There is a conceptual error in what you want to do. Stack accesses are _relative_. > Charles Mott -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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