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man pages section 7: Standards, Environments, Macros, Character Sets, and Miscellany

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Updated: Wednesday, August 8, 2018
 
 

pam_list(7)

Name

pam_list - PAM account management module for UNIX

Synopsis

 pam_list.so.1

Description

The pam_list module implements pam_sm_acct_mgmt(3PAM), which provides functionality to the PAM account management stack. The module provides functions to validate that the user's account is valid on this host based on a list of users and/or netgroups in the given file. The users groups and netgroups are separated by newline character. Groups are specified with character '%' as a prefix. Netgroups are specified with character '@' as prefix before name of netgroup in the list. The maximum line length is 1023 characters. A line containing a single '*' matches any user/group/netgroup. A line starting with a '#' is treated as a comment.

The username is the value of PAM_USER. The host is the value of PAM_RHOST or, if PAM_RHOST is not set, the value of the localhost as returned by gethostname(3C) is used.

If neither of the allow, deny, or compat options are specified, the module will look for +/- entries in the local /etc/passwd file. If this style is used, nsswitch.conf(5) must not be configured with compat for the passwd database. If no relevant +/- entry exists for the user, pam_list is not participating in result.

If compat option is specified then the module will look for +/- entries in the local /etc/passwd file. Other entries in this file will be counted as + entries. If no relevant entry exits for the user, pam_list will deny the access.

When checking group membership both a users primary group and supplementary groups are checked against the group name.

The following options can be passed to the module:

allow=

The full pathname to a file of allowed users and/or netgroups. Only one of allow= or deny= can be specified.

compat

Activate compat mode.

deny=

The full pathname to a file of denied users and/or netgroups. Only one of deny= or allow= can be specified.

debug

Provide syslog(3C) debugging information at the LOG_AUTH | LOG_DEBUG level.

user

The module should only perform netgroup matches on the username. This is the default option.

nouser

The username should not be used in the netgroup match.

group

The allow/deny file contains group names rather than usernames.

host

Only the host should be used in netgroup matches.

nohost

The hostname should not be used in netgroup matches.

norole

Return PAM_IGNORE if the account (PAM_USER) is a role. This is the default.

role

Evaluate the rules even if PAM_USER is a role account.

user_host_exact

The user and hostname must be in the same netgroup.

Errors

The following error values are returned:

PAM_SERVICE_ERR

An invalid set of module options was specified in the PAM configuration (see pam.conf(5)) for this module, or the user/netgroup file could not be opened.

PAM_BUF_ERR

A memory buffer error occurred.

PAM_IGNORE

The module is ignored, as it is not participating in the result.

PAM_PERM_DENIED

The user is not on the allow list or is on the deny list.

PAM_SUCCESS

The account is valid for use at this time.

PAM_USER_UNKNOWN

No account is present for the user

Examples

Example 1 Using pam_list in default mode

The changes to /etc/pam.conf would be:

other   account requisite       pam_roles.so.1
other   account required        pam_unix_account.so.1
other   account required        pam_list.so.1

The equivalent PAM configuration in /etc/pam.d/ would be the following entries in /etc/pam.d/other:

account requisite       pam_roles.so.1
account required        pam_unix_account.so.1
account required        pam_list.so.1

In the case of default mode or compat mode, the important lines in /etc/passwd appear as follows:

+loginname	- user is approved
-loginname	- user is disapproved
+@netgroup	- netgroup members are approved
-@netgroup	- netgroup members are disapproved
Example 2 Using pam_list with allow file

The changes to /etc/pam.conf would be:

other   account requisite       pam_roles.so.1
other   account required        pam_unix_account.so.1
other   account required        pam_list.so.1 allow=/etc/users.allow

The equivalent PAM configuration in /etc/pam.d/ would be the following entries in /etc/pam.d/other:


account requisite       pam_roles.so.1
account required        pam_unix_account.so.1
account required        pam_list.so.1 allow=/etc/users.allow

/etc/users.allow contains:

root
localloginname
remoteloginname
@netgroup

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
MT-Safe with exceptions

The interfaces in libpam(3LIB) are MT-Safe only if each thread within the multithreaded application uses its own PAM handle.

See Also

syslog(3C), libpam(3LIB), pam_authenticate(3PAM), pam(3PAM), pam_sm_acct_mgmt(3PAM), nsswitch.conf(5), pam.conf(5), attributes(7)