Could we harden GCC's stack smashing? (Re: Adam Zabrocki's Adventure with stack smashing protection)

[Ian Lance Taylor]

On Sat, Mar 29, 2014 at 10:52 AM, Steven Stewart-Gallus
<sstewartgallus00@mylangara.bc.ca> wrote:
>
> Adam Zabrocki's Adventure with stack smashing protection at
> (http://blog.pi3.com.pl/?p=485 ) is kind of interesting. It lists some possible
> weaknesses in GCC's -fstack-protector. Given that the weaknesses happen when the
> stack has already been smashed I do not think they are critical but they do bug
> me. I think that the issues happen due to the fundamental problem with the
> approach that GCC's reporting method is taking. Instead of dealing with the
> messed up state of the process it could exec a whole new process or simply
> abort. We could also actually raise our own SIGSEGV signal. I coded up a small
> illustration of how the exec strategy would work.

Thanks.  The code in question is actually part of glibc, not GCC.  All
GCC does is call __stack_chk_fail.  You may want to take your concerns
to the glibc developers--see http://sourceware.org/glibc.

GCC does have it's own copy of __stack_chk_fail in libssp, but it's
simpler than the glibc version.

Ian