I'm using pam_oath.so from the libpam_oath package to use my yubikey to login. Its configured as OATH-HOTP and it's working fine. I can login with my pin and a press on my yubikey. I dont need to enter my user-pw when login in to my account.
But when I lock the screen and try to unlock it I cant use my yubikey alone. I always have to enter my password. It doesn't even matter if I enter the correct pin and I also can discard the whole yubikey-authentication (by just pressing enter) as long as I enter my correct user password, I can unlock the screen.
This is config line I use in /etc/pam.d/common-auth:
auth sufficient pam_oath.so usersfile=/etc/users.oath window=20 digits=8
I tried to enter the same line in various config files in pam.d, for example lightdm, lightdm-greeter, unity but nothing changed the behaviour.
Can anyone explain me where my error is, or what the correct syntax must be if I want to be able to unlock the screen when using my pin + yubikey.
I no it's possible, because if you use freeradius + yubikey and pin, you are able to unlock your locked screen with pin + yubikey.
Any hint how to hunt the error is also much appreciated!