The entire argumentation here is ridiculous. There's a big jump from "IFUNC undermines RELRO" to "IFUNC is the issue". You could have gotten all but the same effect spawning a thread from a plain init or C++ constructor. No one should think that any relro, r^x or aslr or anything like this is going to deter anyone who can literally control the contents of the libraries which are linked in. They could, literally, spawn a copy of sshd with a patched config if necessary.

Sure, but distros not using systemd were not affected.