PAM ordering on Ubuntu 22: pam_unix.so vs pam_sss.so vs pam_systemd.so and the order that breaks SSH if you flip it
I joined a new client’s box one morning to set up SSO via SSSD. By the afternoon, no one — including me, including root — could SSH in. The PAM stack had been rearranged subtly in /etc/pam.d/common-auth, and a …