pam_group

PAM_GROUP(8)                   Linux-PAM Manual                   PAM_GROUP(8)

NAME
       pam_group - PAM module for group access

SYNOPSIS
       pam_group.so

DESCRIPTION
       The pam_group PAM module does not authenticate the user, but instead it
       grants group memberships (in the credential setting phase of the
       authentication module) to the user. Such memberships are based on the
       service they are applying for.

       By default rules for group memberships are taken from config file
       /etc/security/group.conf.

       This module's usefulness relies on the file-systems accessible to the
       user. The point being that once granted the membership of a group, the
       user may attempt to create a setgid binary with a restricted group
       ownership. Later, when the user is not given membership to this group,
       they can recover group membership with the precompiled binary. The
       reason that the file-systems that the user has access to are so
       significant, is the fact that when a system is mounted nosuid the user
       is unable to create or execute such a binary file. For this module to
       provide any level of security, all file-systems that the user has write
       access to should be mounted nosuid.

       The pam_group module functions in parallel with the /etc/group file. If
       the user is granted any groups based on the behavior of this module,
       they are granted in addition to those entries /etc/group (or
       equivalent).

OPTIONS
       This module does not recognise any options.

MODULE TYPES PROVIDED
       Only the auth module type is provided.

RETURN VALUES
       PAM_SUCCESS
           group membership was granted.

       PAM_ABORT
           Not all relevant data could be gotten.

       PAM_BUF_ERR
           Memory buffer error.

       PAM_CRED_ERR
           Group membership was not granted.

       PAM_IGNORE
           pam_sm_authenticate was called which does nothing.

       PAM_USER_UNKNOWN
           The user is not known to the system.

FILES
       /etc/security/group.conf
           Default configuration file

SEE ALSO
       group.conf(5), pam.d(5), pam(7).

AUTHORS
       pam_group was written by Andrew G. Morgan <morgan@kernel.org>.

Linux-PAM Manual                  05/18/2017                      PAM_GROUP(8)