Comment 52 for bug 1085706

Confirming issue exists on Kubuntu 20.04.4 LTS.

Every attempt to login from the graphical login screen makes this error appear in authlog:

    /var/log/auth.log:Apr 27 13:56:16 <hostname> kcheckpass[3516]: pam_ecryptfs: seteuid error

Quick "fix" of the symptom, i.e. make the error go away is to add the seteuid-bit permission to kcheckpass (owned by root):

    sudo chmod u+s /usr/lib/x86_64-linux-gnu/libexec/kcheckpass

However, this seems like a too broad privilege grant so I'm not sure it is a good idea.
Personally, I prefer to have the spurious error in the log over this broad privilege grant.

Note that login succeeds despite the error appearing in authlog.