Messages in this thread | | | From | Systemkennung Linux <> | Subject | Re: 2nd Linux kernel patch to remove stack exec | Date | Mon, 14 Apr 1997 00:26:59 +0200 (MET DST) |
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Hi,
> It's not really a problem -- everything should run just fine with my patch. > However, the patch will not prevent buffer overflow exploits for those > programs that use trampolines. > > This means that as long as libc5 is being used, most (if not all) privileged > processes will have stack execution permission disabled. :) > > As for glibc, maybe it is time to change it not to use trampolines?
A patch which does this should now be in the glibc 2.1 development source.
> > Admited trampolines are a stupid idea because their performance sucks > > on many architectures. > > AFAIK, they will cause some overhead for maintaining L1 code and data caches > coherency, since the stack frame is usually in the data cache -- resulting in > bad performance.
We're talking about some hundred cycles or more ...
Ralf
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