[CentOS] Glibc sources?

All,

Please excuse any ignorance in this e-mail as I am not a RH/CentOS/Fedora user and may
blunder my way through the correct terminology for my request.

I'm tasked with reconstructing the CentOS version of the GlibC library for testing with
gethostbyname().  My mission is to show that we are not affected by the latest exploit for
the product we are shipping targeted for RHEL and CentOS.  To do so, I want to equip
gethostbyname() with additional code.

My objective is to rebuild from source the EXACT version of GlibC for CentOS 6.6.
Afterwards, I will make my changes in the code, rebuild and complete my testing.

libc.so.6 reports:
GNU C Library stable release version 2.12, by Roland McGrath et al.
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.4.7 20120313 (Red Hat 4.4.7-11).
Compiled on a Linux 2.6.32 system on 2015-01-27.
Available extensions:
        The C stubs add-on version 2.1.2.
        crypt add-on version 2.1 by Michael Glad and others
        GNU Libidn by Simon Josefsson
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
        RT using linux kernel aio
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

But, when looking through the source code for this version on the CentOS servers I only see:
<http://vault.centos.org/6.6/updates/Source/SPackages/>
[ ]	glibc-2.12-1.149.el6_6.4.src.rpm	07-Jan-2015 22:45 	15M	 
[ ]	glibc-2.12-1.149.el6_6.5.src.rpm	27-Jan-2015 23:13 	15M	 

Please point me to the correct source tarball, and all required patches so that I can
reconstruct my loaded version of GlibC.  A yum command is also acceptable.

Thanks,
Andy