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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 AT kernel.org>.



Linux-PAM Manual                             06/08/2020                                 PAM_GROUP(8)