Multiple libraries privilege checking (PATCH for RPM e popt from open wall)

On the oss-security mailing list Sebastian Krahmer wrote :
"Hi,

Its probably about time to review libraries that are commonly
linked to (formerly-) suid programs, such as
libldap, libssl etc. In near future, in the advent of file caps
they are often lacking proper checks.
They usually just compare uid against euid (not even gid sometimes)
and do not check the dumpable flag or AT_SECURE (dont know whether
glibc exports a proper function to easily check that at all).
"
(look here for the complete post : http://article.gmane.org/gmane.comp.security.oss.general/5061)

and Solar Designer of the project Openwall answered :
"> Its probably about time to review libraries that are commonly
> linked to (formerly-) suid programs, such as
> libldap, libssl etc. In near future, in the advent of file caps
> they are often lacking proper checks.

Good idea.

> They usually just compare uid against euid (not even gid sometimes)
> and do not check the dumpable flag or AT_SECURE (dont know whether
> glibc exports a proper function to easily check that at all).

glibc exports the __libc_enable_secure variable, which is initialized
based on AT_* including AT_SECURE. It also exports __secure_getenv().
"
(look here for the complete post http://article.gmane.org/gmane.comp.security.oss.general/5066).

So i think is not so bad to review the path posted above and integrate it if applicable in popt 1.17DEVEL HEAD