Shadow and PAM

А в /etc/pam.d/login у pam_pwdb shadow прописать не могли забыть?

На правах примера.
/etc/pam.d/login:
auth required /lib/security/pam_securetty.so
auth required /lib/security/pam_pwdb.so shadow nullok
auth required /lib/security/pam_nologin.so
account required /lib/security/pam_pwdb.so
password required /lib/security/pam_cracklib.so
password required /lib/security/pam_pwdb.so nullok use_authtok md5 shadow
session required /lib/security/pam_pwdb.so
session optional /lib/security/pam_console.so