Description of problem:

Set nothing to pam_sss option "domains=" in /etc/pam.d/password-auth-ac file. Try to authenticate a trusted user and authentication succeeds. Also, following message gets logged in /var/log/secure file:

sshd[21815]: pam_sss(sshd:setcred): Missing argument to option domains.

Ideally trusted user auth should fail as arguments to domains option are missing and it is not clear which restricted domain pam service should authenticate against. An alternate solution is to provide information in man page as to what happens when domains=<empty value>. 

Version-Release number of selected component (if applicable):
sssd-1.12.2-12.el7.x86_64

How reproducible:
Always

Steps to Reproduce:
1. Configure SSSD client with LDAP domain and set empty value to "domains=" option in pam file. Edit the sssd.conf file as given below:

[sssd]
config_file_version = 2
domains = LDAP
services = nss, pam
sbus_timeout = 30

[pam]
debug_level = 0xFFF0
pam_trusted_users = user1
pam_public_domains = all

[domain/LDAP]
id_provider = ldap
auth_provider = ldap
debug_level = 5
cache_credentials = FALSE
ldap_uri = ldaps://seaspray.lab.eng.pnq.redhat.com
ldap_tls_cacert = /etc/openldap/certs/server.pem
ldap_search_base = dc=example,dc=com

2. Also, edit "auth" section of the /etc/pam.d/password-auth-ac in SSSD client as given below:

auth        required      pam_env.so
auth        sufficient    pam_unix.so nullok try_first_pass
auth        requisite     pam_succeed_if.so uid >= 1000 quiet_success
auth        sufficient    pam_sss.so use_first_pass domains=
auth        required      pam_deny.so

3. Execute trusted user auth as given below:

# ssh -l user1 localhost
usr1@localhost's password: 
Last login: Mon Nov 24 20:12:07 2014 from localhost
Could not chdir to home directory /home/usr1: No such file or directory
id: cannot find name for group ID 11111
-sh-4.2$ logout

Actual results:
User auth successful with the following message in secure file:

sshd[21815]: pam_sss(sshd:setcred): Missing argument to option domains.

Expected results:
Either user auth should fail with the above message OR Man page should be updated with relevant information as to which domain, PAM service is allowed to authenticate against when domains=<empty> 

Additional info: