PAM.CONF(5)

NAME
pam.conf - PAM policy file format

DESCRIPTION
The PAM library searches for policies in the following files, in decreasing order of preference:

1.  /etc/pam.d/service-name

2.  /etc/pam.conf

3.  /usr/local/etc/pam.d/service-name

4.  /usr/local/etc/pam.conf

If none of these locations contains a policy for the given service, the “other” policy is used instead, if it exists.

Entries in per-service policy files must be of one of the two forms below:

    [-]facility control-flag module-path [arguments ...]
    [-]facility include other-service-name

Entries in pam.conf-style policy files are of the same form, but are prefixed by an additional field specifying the name of the service they apply to.

In both cases, blank lines and comments introduced by a ‘#’ sign are ignored, and the normal shell quoting rules apply. The precise details of how the file is tokenized are described in openpam_readword(3).

The facility field specifies the facility the entry applies to, and is one of:

auth
    Authentication functions ( pam_authenticate(3), pam_setcred(3))

account
    Account management functions (pam_acct_mgmt(3))

session
    Session handling functions ( pam_open_session(3), pam_close_session(3))

password
    Password management functions (pam_chauthtok(3))

The facility field may optionally be preceded by a dash (‘-’), which indicates that failure to load the specified module (or policy if the control-flag is include) should not be considered a fatal error. This is intended for situations where it is desirable to share a single policy across multiple systems, but certain additional modules or policies may only be present on some of them.

The control-flag field determines how the result returned by the module affects the flow of control through (and the final result of) the rest of the chain, and is one of:

required
    If this module succeeds, the result of the chain will be success unless a later module fails. If it fails, the rest of the chain still runs, but the final result will be failure regardless of the success of later modules.

requisite
    If this module succeeds, the result of the chain will be success unless a later module fails. If the module fails, the chain is broken and the result is failure.

sufficient
    If this module succeeds, the chain is broken and the result is success. If it fails, the rest of the chain still runs, but the final result will be failure unless a later module succeeds.

binding
    If this module succeeds, the chain is broken and the result is success. If it fails, the rest of the chain still runs, but the final result will be failure regardless of the success of later modules.

optional
    If this module succeeds, the result of the chain will be success unless a later module fails. If this module fails, the result of the chain will be failure unless a later module succeeds.

There are two exceptions to the above: sufficient and binding modules are treated as optional by pam_setcred(3), and in the PAM_PRELIM_CHECK phase of pam_chauthtok(3).

The module-path field specifies the name or full path of the module to call. If only the name is specified, the PAM library will search for it in the following locations:

1.  /usr/lib

2.  /usr/local/lib

The remaining fields, if any, are passed unmodified to the module if and when it is invoked.

The include form of entry causes entries from a different chain (specified by other-system-name) to be included in the current one. This allows one to define system-wide policies which are then included into service-specific policies. The system-wide policy can then be modified without having to also modify each and every service-specific policy.

Take care not to introduce loops when using include rules, as there is currently no loop detection in place.

MODULE OPTIONS
Some PAM library functions may alter their behavior when called by a service module if certain module options were specified, regardless of whether the module itself accords them any importance. One such option is debug, which causes the dispatcher to enable debugging messages before calling each service function, and disable them afterwards (unless they were already enabled). Other special options include:

authtok_prompt=prompt, oldauthtok_prompt=prompt, user_prompt=prompt
    These options can be used to override the prompts used by pam_get_authtok(3) and pam_get_user(3).

echo_pass
    This option controls whether pam_get_authtok(3) will allow the user to see what they are typing.

try_first_pass, use_first_pass
    These options control pam_get_authtok(3)'s use of cached authentication tokens.

SEE ALSO
pam(3)

STANDARDS
X/Open Single Sign-On Service (XSSO) - Pluggable Authentication Modules, June 1997.

AUTHORS
The OpenPAM library was developed for the FreeBSD Project by ThinkSec AS and Network Associates Laboratories, the Security Research Division of Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 (“CBOSS”), as part of the DARPA CHATS research program.

The OpenPAM library is maintained by Dag-Erling Smørgrav <des@des.dev>.