pam_group(8)

1PAM_GROUP(8)                   Linux-PAM Manual                   PAM_GROUP(8)
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NAME

6       pam_group - PAM module for group access
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SYNOPSIS

9       pam_group.so
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DESCRIPTION

12       The pam_group PAM module does not authenticate the user, but instead it
13       grants group memberships (in the credential setting phase of the
14       authentication module) to the user. Such memberships are based on the
15       service they are applying for.
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17       By default rules for group memberships are taken from config file
18       /etc/security/group.conf.
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20       This module's usefulness relies on the file-systems accessible to the
21       user. The point being that once granted the membership of a group, the
22       user may attempt to create a setgid binary with a restricted group
23       ownership. Later, when the user is not given membership to this group,
24       they can recover group membership with the precompiled binary. The
25       reason that the file-systems that the user has access to are so
26       significant, is the fact that when a system is mounted nosuid the user
27       is unable to create or execute such a binary file. For this module to
28       provide any level of security, all file-systems that the user has write
29       access to should be mounted nosuid.
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31       The pam_group module functions in parallel with the /etc/group file. If
32       the user is granted any groups based on the behavior of this module,
33       they are granted in addition to those entries /etc/group (or
34       equivalent).
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OPTIONS

37       This module does not recognise any options.
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MODULE TYPES PROVIDED

40       Only the auth module type is provided.
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RETURN VALUES

43       PAM_SUCCESS
44           group membership was granted.
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46       PAM_ABORT
47           Not all relevant data could be gotten.
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49       PAM_BUF_ERR
50           Memory buffer error.
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52       PAM_CRED_ERR
53           Group membership was not granted.
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55       PAM_IGNORE
56           pam_sm_authenticate was called which does nothing.
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58       PAM_USER_UNKNOWN
59           The user is not known to the system.
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FILES

62       /etc/security/group.conf
63           Default configuration file
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AUTHORS

69       pam_group was written by Andrew G. Morgan <morgan@kernel.org>.
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73Linux-PAM Manual                  09/03/2021                      PAM_GROUP(8)