Re: Compiler alternatives to no-exec (was Re: non exec stack...)

Erik Corry (erik@arbat.com)
Tue, 11 Aug 1998 19:23:10 +0200

In article <19980811184156.49153@lucifer.guardian.no> Alexander wrote:
> On Fri, Aug 07, 1998 at 06:20:07AM +0000, Linus Torvalds wrote:
>>
>> There's an even simpler fix, with the compiler just pushing 0 on entry
>> to all functions, and on exit it pops it off and aborts if it is
>> non-zero.

> I have a preliminary implementation of this for egcs 1.03a. I tested
> the overhead on gzip - it looks pretty good. I use the following
> pattern which ensures that the branch is predicted non-taken:

Are you aware of Stackguard. They have a modified gcc that does
more or less this, and are in the process of building a version
of Red Hat 5.1 that uses it. It was already mentioned here:

http://www.cse.ogi.edu/DISC/projects/immunix/StackGuard/

-- 
Erik Corry


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