Re: propolice support for linux
From: Han Boetes
Date: Thu Jan 13 2005 - 18:04:42 EST
Ulrich Drepper wrote:
> Aside from all the arguments about why this patch isn't good for
> the kernel, everybody should be aware that the ProPolice gcc
> patches are pretty unusable. They rely in recognizing certain
> tree patterns which for some architectures do not exist, and for
> others can look differently, depending on the optimization. To
> paraphrase one of the gcc developers: "this kind of
> functionality should be written to work _with_ gcc, not
> _against_ it as the propolice patch does".
>
> Before you suggest using something like this patch you better
> first inform yourself by asking the people who actually know the
> code which is modified.
Ok I have a problem here. You are Ulrich Drepper and you are _the_
maintainer of glibc and I am Han Boetes and I am a C noob. It's
like Kasparov trying to explain something to a club-chess-player.
I'm afraid that whatever explanation you give to me is over my
head, you'll feel like talking to a dummy and I'll be terribly
unsatisfied.
To avoid that I would like to ask you if you can show me some
example-code, something I which can compile and run and see for
myself, for the following situations:
1) Where an application compiled with PP is working worse or even
failing where it would work right without PP.
2) Where a bufferoverflow can be exploited even though the
application is compiled with PP.
As an example where PP does work right the test-code provided by
the propolice maintainer:
/* test-propolice.c */
#define OVERFLOW "This is longer than 10 bytes"
#include <string.h>
int main (int argc, char *argv[]) {
char buffer[10];
strcpy(buffer, OVERFLOW);
return 0;
}
# Han
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