LCLS Server Access

RHEL4:

PAM is the pluggable authentication modules. It is a system that most Linux distributions have incorporated that gives you fine grained control over how users are authenticated.

We use one of the modules, namely, pam_access.so, to create a restrict login access on Linux hosts on CA network.

The configuration can be set by individual configuration files located in the /etc/pam.d, the service is the name of the file, e.g. sshd, in this case.

The pam_access.so in /lib/security is the program that enforces the rules.

Some of the modules have additional configuration files in /etc/security.

The /etc/security/access.conf can be used to greatly restrict who can login from where.

Take lcls-daemon1 for example:

Configure /etc/pam.d/sshd

on lcls-daemon1

cd /etc/pam.d

cp sshd sshd.dist

chmod u-w sshd.dist

vi sshd and Append following entry

# add login restrictions (access.conf)

account required pam_access.so

Configure /etc/security

cd /etc/security

cp access.conf access.conf.dist

chmod u-w access.conf.dist

vi access.conf and Append following entry

# Only allow root laci uwd jingchen brobeck divekar to login from anywhere

-:ALL EXCEPT root laci uwd jingchen brobeck divekar:ALL

Test login and monitor the login access

tail -f /var/log/messages

RHEL6:

/etc/pam.d/sshd:

#%PAM-1.0
auth required pam_sepermit.so
auth include password-auth
account required pam_nologin.so
#account include password-auth
password include password-auth
# pam_selinux.so close should be the first session rule
#session required pam_selinux.so close
session required pam_loginuid.so
# pam_selinux.so open should only be followed by sessions to be executed in the user context
#session required pam_selinux.so open env_params
session optional pam_keyinit.so force revoke
session include password-auth
account required pam_access.so

/etc/security/access.conf:

Added:

# Only allow root uwd jingchen brobeck divekar to login
-:ALL EXCEPT root uwd jingchen brobeck divekar:ALL