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Two problem about "using pam to limit user login"
OS£½RHEL 3 AS
Problem 1: use pam.wheel to limit users who can su to root
”°/etc/pam.d/su”± file content as follows:
auth sufficient /lib/security/pam_rootok.so
auth required /lib/security/pam_wheel.so use_uid group=admin
# only allow the members of ”°admin”± group to su to root
auth required /lib/security/pam_stack.so service=system-auth
account required /lib/security/pam_stack.so service=system-auth
password required /lib/security/pam_stack.so service=system-auth
session required /lib/security/pam_stack.so service=system-auth
session optional /lib/security/pam_xauth.so
now we suppose there are 3 users , they are: alice , bob and courer
# usermod -G admin alice
after the above setting, only alice can su to root, but bob cannot.
the question is : bob unexpectedly cannot su to a common user such as courer too.
Some information in /var/log/message:
PAM-Wheel[3873]: Access denied for 'bob' to 'courer'
2. use pam.limits to limit the system resource
"/etc/pam.d/login" file content as follows:
auth required pam_securetty.so
auth required pam_stack.so service=system-auth
auth required pam_nologin.so
account required pam_stack.so service=system-auth
password required pam_stack.so service=system-auth
session required pam_stack.so service=system-auth
session optional pam_console.so
session required pam_limits.so
"/etc/security/limits.conf" file content as follows:
alice - maxlogins 1
bob - maxlogins 2
courer - maxlogins 0
then, 2 alice can login at the same time, 3 bob can login the same time, courer cannot login
why I cannot only allow one person login at the same time ?
N=n+1 (n>0) ?
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