Re: Sabotaged PaXtest (was: Re: Patch 4/6 randomize the stack pointer)

Peter Busser
2005-02-01T14:48:10Z

On Tuesday 01 February 2005 12:46, you wrote:
> * Peter Busser <busser@m-privacy.de> wrote:
> > > ok the paxtest 0.9.5 I downloaded from a security site (not yours) had
> > > this gem in:
> > >
> > > + do_mprotect((unsigned long)argv & ~4095U, 4096,
> > > PROT_READ|PROT_WRITE|PROT_EXEC);
> > >
> > > which is clearly there to sabotage any segmentation based approach (eg
> > > execshield and openwall etc); it cannot have any other possible use or
> > > meaning.
> > >
> > > the paxtest 0.9.6 that John Moser mailed to this list had this gem in
> > > it:
> > >
> > > + /* Dummy nested function */
> > > + void dummy(void) {}
> > >
> > > which is clearly there with the only possible function of sabotaging
> > > the automatic PT_GNU_STACK setting by the toolchain (which btw is not
> > > fedora specific but happens by all new enough (3.3 or later) gcc
> > > compilers on all distros) since that requires an executable stack.
>
> [...]
>
> > No, these things are also in the officially released sources. I put
> > them in myself in fact.
>
> *PLONK*

You still don't get it, do you?

Groetjes,
Peter.