pam_get_authtok.c revision 96364 
1/*-
2 * Copyright (c) 2002 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * NAI Labs, the Security Research Division of Network Associates, Inc.
7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
8 * DARPA CHATS research program.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $P4: //depot/projects/openpam/lib/pam_get_authtok.c#17 $
35 */
36
37#include <sys/param.h>
38
39#include <stdlib.h>
40#include <string.h>
41
42#include <security/pam_appl.h>
43#include <security/openpam.h>
44
45#include "openpam_impl.h"
46
47const char authtok_prompt[] = "Password:";
48const char oldauthtok_prompt[] = "Old Password:";
49const char newauthtok_prompt[] = "New Password:";
50
51/*
52 * OpenPAM extension
53 *
54 * Retrieve authentication token
55 */
56
57int
58pam_get_authtok(pam_handle_t *pamh,
59	int item,
60	const char **authtok,
61	const char *prompt)
62{
63	const void *oldauthtok;
64	const char *default_prompt;
65	char *resp, *resp2;
66	int pitem, r, style, twice;
67
68	if (pamh == NULL || authtok == NULL)
69		return (PAM_SYSTEM_ERR);
70
71	*authtok = NULL;
72	twice = 0;
73	switch (item) {
74	case PAM_AUTHTOK:
75		pitem = PAM_AUTHTOK_PROMPT;
76		default_prompt = authtok_prompt;
77		r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok);
78		if (r == PAM_SUCCESS && oldauthtok != NULL) {
79			default_prompt = newauthtok_prompt;
80			twice = 1;
81		}
82		break;
83	case PAM_OLDAUTHTOK:
84		pitem = PAM_OLDAUTHTOK_PROMPT;
85		default_prompt = oldauthtok_prompt;
86		twice = 0;
87		break;
88	default:
89		return (PAM_SYMBOL_ERR);
90	}
91
92	if (openpam_get_option(pamh, "try_first_pass") ||
93	    openpam_get_option(pamh, "use_first_pass")) {
94		r = pam_get_item(pamh, item, (const void **)authtok);
95		if (r == PAM_SUCCESS && *authtok != NULL)
96			return (PAM_SUCCESS);
97		else if (openpam_get_option(pamh, "use_first_pass"))
98			return (r == PAM_SUCCESS ? PAM_AUTH_ERR : r);
99	}
100	if (prompt == NULL) {
101		r = pam_get_item(pamh, pitem, (const void **)&prompt);
102		if (r != PAM_SUCCESS || prompt == NULL)
103			prompt = default_prompt;
104	}
105	style = openpam_get_option(pamh, "echo_pass") ?
106	    PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF;
107	r = pam_prompt(pamh, style, &resp, "%s", prompt);
108	if (r != PAM_SUCCESS)
109		return (r);
110	if (twice) {
111		r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt);
112		if (r != PAM_SUCCESS) {
113			free(resp);
114			return (r);
115		}
116		if (strcmp(resp, resp2) != 0) {
117			free(resp);
118			resp = NULL;
119		}
120		free(resp2);
121	}
122	if (resp == NULL)
123		return (PAM_TRY_AGAIN);
124	r = pam_set_item(pamh, item, resp);
125	free(resp);
126	if (r != PAM_SUCCESS)
127		return (r);
128	return (pam_get_item(pamh, item, (const void **)authtok));
129}
130
131/*
132 * Error codes:
133 *
134 *	=pam_get_item
135 *	=pam_prompt
136 *	=pam_set_item
137 *	!PAM_SYMBOL_ERR
138 *	PAM_TRY_AGAIN
139 */
140
141/**
142 * The =pam_get_authtok function returns the cached authentication token,
143 * or prompts the user if no token is currently cached.  Either way, a
144 * pointer to the authentication token is stored in the location pointed
145 * to by the =authtok argument.
146 *
147 * The =item argument must have one of the following values:
148 *
149 *	=PAM_AUTHTOK:
150 *		Returns the current authentication token, or the new token
151 *		when changing authentication tokens.
152 *	=PAM_OLDAUTHTOK:
153 *		Returns the previous authentication token when changing
154 *		authentication tokens.
155 *
156 * The =prompt argument specifies a prompt to use if no token is cached.
157 * If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item,
158 * as appropriate, will be used.  If that item is also =NULL, a hardcoded
159 * default prompt will be used.
160 *
161 * If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK
162 * item, =pam_get_authtok will ask the user to confirm the new token by
163 * retyping it.  If there is a mismatch, =pam_get_authtok will return
164 * =PAM_TRY_AGAIN.
165 *
166 * >pam_get_item
167 * >pam_get_user
168 */
169