gcc FORTIFY_SOURCE application security flags

[Florian Weimer]

* Matthias Baesken:

> I would prefer to get a hs_err file, do you know a way to get this in
> context of the gcc flag _FORTIFY_SOURCE ?

__fortify_fail should eventually raise SIGABRT.  So if you install a
handler for that signal, you should be able to generate hs_err file.

__fortify_fail is different from the other checks in that typically runs
*before* memory corruption occurs, so it could be fairly safe to do
in-process error logging.  But that's not necessarily true for other
process aborts, so intercepting SIGABRT could increase exposure.

Thanks,
Florian