1PAM(3) User Contributed Perl Documentation PAM(3)
2
6 Authen::PAM - Perl interface to PAM library
7
9 use Authen::PAM;
10 $res = pam_start($service_name, $pamh);
12 $res = pam_start($service_name, $user, $pamh);
13 $res = pam_start($service_name, $user, \&my_conv_func, $pamh);
14 $res = pam_end($pamh, $pam_status);
15 $res = pam_authenticate($pamh, $flags);
17 $res = pam_setcred($pamh, $flags);
18 $res = pam_acct_mgmt($pamh, $flags);
19 $res = pam_open_session($pamh, $flags);
20 $res = pam_close_session($pamh, $flags);
21 $res = pam_chauthtok($pamh, $flags);
22 $error_str = pam_strerror($pamh, $errnum);
24 $res = pam_set_item($pamh, $item_type, $item);
26 $res = pam_get_item($pamh, $item_type, $item);
27 if (HAVE_PAM_ENV_FUNCTIONS()) {
29 $res = pam_putenv($pamh, $name_value);
30 $val = pam_getenv($pamh, $name);
31 %env = pam_getenvlist($pamh);
32 }
33 if (HAVE_PAM_FAIL_DELAY()) {
35 $res = pam_fail_delay($pamh, $musec_delay);
36 $res = pam_set_item($pamh, PAM_FAIL_DELAY(), \&my_fail_delay_func);
37 }
38
40 The Authen::PAM module provides a Perl interface to the PAM library.
41 The only difference with the standard PAM interface is that instead of
42 passing a pam_conv struct which has an additional context parameter
43 appdata_ptr, you must only give an address to a conversation function
44 written in Perl (see below).
45 If you want to pass a NULL pointer as a value of the $user in pam_start
47 use undef or the two-argument version. Both in the two and the three-
48 argument versions of pam_start a default conversation function is used
49 (Authen::PAM::pam_default_conv).
50 The $flags argument is optional for all functions which use it except
52 for pam_setcred. The $pam_status argument is also optional for pam_end
53 function. Both of these arguments will be set to 0 if not given.
54 The names of some constants from the PAM library have changed over the
56 time. You can use any of the known names for a given constant although
57 it is advisable to use the latest one.
58 When this module supports some of the additional features of the PAM
60 library (e.g. pam_fail_delay) then the corresponding HAVE_PAM_XXX
61 constant will have a value 1 otherwise it will return 0.
62 For compatibility with older PAM libraries I have added the constant
64 HAVE_PAM_ENV_FUNCTIONS which is true if your PAM library has the
65 functions for handling environment variables (pam_putenv, pam_getenv,
66 pam_getenvlist).
67 Object Oriented Style
69 If you prefer to use an object oriented style for accessing the PAM
70 library here is the interface:
71 use Authen::PAM qw(:constants);
73 $pamh = new Authen::PAM($service_name);
75 $pamh = new Authen::PAM($service_name, $user);
76 $pamh = new Authen::PAM($service_name, $user, \&my_conv_func);
77 ref($pamh) || die "Error code $pamh during PAM init!";
79 $res = $pamh->pam_authenticate($flags);
81 $res = $pamh->pam_setcred($flags);
82 $res = $pamh->pam_acct_mgmt($flags);
83 $res = $pamh->pam_open_session($flags);
84 $res = $pamh->pam_close_session($flags);
85 $res = $pamh->pam_chauthtok($flags);
86 $error_str = $pamh->pam_strerror($errnum);
88 $res = $pamh->pam_set_item($item_type, $item);
90 $res = $pamh->pam_get_item($item_type, $item);
91 $res = $pamh->pam_putenv($name_value);
93 $val = $pamh->pam_getenv($name);
94 %env = $pamh->pam_getenvlist;
95 The constructor new will call the pam_start function and if successfull
97 will return an object reference. Otherwise the $pamh will contain the
98 error number returned by pam_start. The pam_end function will be
99 called automatically when the object is no longer referenced.
100 Examples
102 Here is an example of using PAM for changing the password of the
103 current user:
104 use Authen::PAM;
106 $login_name = getpwuid($<);
108 pam_start("passwd", $login_name, $pamh);
110 pam_chauthtok($pamh);
111 pam_end($pamh);
112 or the same thing but using OO style:
114 $pamh = new Authen::PAM("passwd", $login_name);
116 $pamh->pam_chauthtok;
117 $pamh = 0; # Force perl to call the destructor for the $pamh
118 Conversation function format
120 When starting the PAM the user must supply a conversation function. It
121 is used for interaction between the PAM modules and the user. The
122 argument of the function is a list of pairs ($msg_type, $msg) and it
123 must return a list with the same number of pairs ($resp_retcode, $resp)
124 with replies to the input messages. For now the $resp_retcode is not
125 used and must be always set to 0. In addition the user must append to
126 the end of the resulting list the return code of the conversation
127 function (usually PAM_SUCCESS). If you want to abort the conversation
128 function for some reason then just return an error code, normally
129 PAM_CONV_ERR.
130 Here is a sample form of the PAM conversation function:
132 sub my_conv_func {
134 my @res;
135 while ( @_ ) {
136 my $msg_type = shift;
137 my $msg = shift;
138 print $msg;
140 # switch ($msg_type) { obtain value for $ans; }
142 push @res, (0,$ans);
144 }
145 push @res, PAM_SUCCESS();
146 return @res;
147 }
148 More examples can be found in the Authen::PAM:FAQ.
150
152 The following constant names: PAM_AUTHTOKEN_REQD, PAM_CRED_ESTABLISH,
153 PAM_CRED_DELETE, PAM_CRED_REINITIALIZE, PAM_CRED_REFRESH are used by
154 some older version of the Linux-PAM library and are not exported by
155 default. If you really want them, load the module with
156 use Authen::PAM qw(:DEFAULT :old);
158 This module still does not support some of the new Linux-PAM functions
160 such as pam_system_log.
161
163 PAM Application developer's Manual, Authen::PAM::FAQ
164
166 Nikolay Pelov <NIKIP at cpan.org>
167
169 Copyright (c) 1998-2005 Nikolay Pelov. All rights reserved. This
170 program is free software; you can redistribute it and/or modify it
171 under the same terms as Perl itself.
172perl v5.36.0 2023-01-20 PAM(3)