Messages in this thread |  | | | From | (H. Peter Anvin) | | Subject | Re: 64bit port | | Date | 1 May 1999 10:29:25 GMT |
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Followup to: <Pine.LNX.4.10.9905011108010.2314-100000@tahallah.demon.co.uk> By author: Alex Buell <alex.buell@tahallah.demon.co.uk> In newsgroup: linux.dev.kernel > On Sat, 1 May 1999, David Miller wrote: > > > When Jakub and I get the 64-bit userland bootstrapped, I'll start > > running crashme to learn what the exact instruction sequences are so > > we have a chance at coding a more suitable workaround than what > > Solaris has chosen. > > How about a run-time mechanism for detecting illegal instructions and > modifying them into harmless NOP sequences? > > Ie. on loading of a binary could quickly scan it for illegal sequences and > overwrite with NOPs, then execute it. Of course, this doesn't cater for > things that does J-I-T compilation & execution though. >
No good... it's trivial for the malicious user to bypass the simple-minded check. The general problem is uncomputable.
-hpa -- "The user's computer downloads the ActiveX code and simulates a 'Blue Screen' crash, a generally benign event most users are familiar with and that would not necessarily arouse suspicions." -- Security exploit description on http://www.zks.net/p3/how.asp
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