Re: [gentoo-hardened] SSP + setjmp() = badness?

[Peter S. Mazinger]

On Sun, 6 Aug 2006, Ned Ludd wrote:

> On Sun, 2006-08-06 at 13:17 +0200, Peter S. Mazinger wrote:
> > On Mon, 31 Jul 2006, Ned Ludd wrote:
> >
> > > On Mon, 2006-07-31 at 20:33 +0200, pageexec@××××××××.hu wrote:
> > > > On 31 Jul 2006 at 11:28, Ned Ludd wrote:
> > > > > gcc-4.x and hardened are not in the works..
> > > > > We are undecided at this time how much we wish to pursue that avenue.
> > > >
> > > > which part of hardened gcc is in question? i'd think that at least
> > > > PIE/RELRO/BIND_NOW are as easy to support as in 3.x.
> > >
> > > Yes these would be pretty trivial to do.
> > >
> > > > ssp may or may
> > > > not be a good idea given how new the 4.x series is, but as Mike said,
> > > > at least there's an eager upstream to fix any issues.
> >
> > toolchain.eclass misses the needed support for gcc-4.1 like ssp
> >
> > > I think the major problem we are facing here is how to cleanly upgrade
> > > from 3.x to 4.x. symbol names have changed. And using the stub/aliases
> > > method Peter used in uClibc svn allows the __guard to be overwritten.
> >
> > How can __guard be overwritten, it is even marked with attribute_relro?
>
> We tested and talked about this before peter..
> None the less here is a simple testcase for you.
>
> extern unsigned long __guard;
>
> void fail() {
>         __guard = 0;
> }
>
> int main() {
>         puts("This should fail");
>         fail();
>         puts("This should not be reached");
>         return 0;
> }
>
>
> ./guardtest
> This should fail
> main: stack smashing attack in function fail()
> Aborted
>
> You results should be similar.

No, it works for me correctly/securely

Peter

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Peter S. Mazinger <ps dot m at gmx dot net>           ID: 0xA5F059F2
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