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.
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.