pam.conf
—
PAM policy file format
The PAM library searches for policies in the following files, in decreasing
order of preference:
- /etc/pam.d/service-name
- /etc/pam.conf
- /usr/local/etc/pam.d/service-name
- /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 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:
- /usr/lib
- /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.
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.
X/Open Single Sign-On Service (XSSO) -
Pluggable Authentication Modules, June
1997.
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.no>.