pam_group(8) — Linux manual page


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

NAME         top

       pam_group - PAM module for group access

SYNOPSIS         top

DESCRIPTION         top

       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

       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         top

       This module does not recognise any options.


       Only the auth module type is provided.

RETURN VALUES         top

           group membership was granted.

           Not all relevant data could be gotten.

           Memory buffer error.

           Group membership was not granted.

           pam_sm_authenticate was called which does nothing.

           The user is not known to the system.

FILES         top

           Default configuration file

SEE ALSO         top

       group.conf(5), pam.d(5), pam(8).

AUTHORS         top

       pam_group was written by Andrew G. Morgan <>.

COLOPHON         top

       This page is part of the linux-pam (Pluggable Authentication
       Modules for Linux) project.  Information about the project can be
       found at ⟨⟩.  If you have a bug report
       for this manual page, see ⟨//⟩.  This page was
       obtained from the tarball Linux-PAM-1.3.0.tar.bz2 fetched from
       ⟨⟩ on 2020-12-18.  If you
       discover any rendering problems in this HTML version of the page,
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       manual page), send a mail to

Linux-PAM Manual               04/01/2016                   PAM_GROUP(8)

Pages that refer to this page: group.conf(5)