Re: Qualys Security Advisory - The Stack Clash

[Jeff Law <law () redhat com>]

On 06/21/2017 04:46 AM, Agostino Sarubbo wrote:
> On Monday 19 June 2017 08:28:43 Qualys Security Advisory wrote:
> > III. Solutions
> > - Recompile all userland code (ld.so, libraries, binaries) with GCC's
> >   "-fstack-check" option, which prevents the stack-pointer from moving
> >   into another memory region without accessing the stack guard-page (it
> >   writes one word to every 4KB page allocated on the stack).
>
> For the record, Gentoo Hardened enables by default -fstack-check=specific
And if you were to look at the generated code, you'll see that it
happily skips 2-3 pages of probes in prologues as well as within alloca
spaces.  It's a false sense of security.

jeff