pam_get_authtok.c revision 93982 
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#15 $
35 */
36
37#include <sys/param.h>
38
39#include <stdlib.h>
40
41#include <security/pam_appl.h>
42#include <security/openpam.h>
43
44#include "openpam_impl.h"
45
46const char authtok_prompt[] = "Password:";
47const char oldauthtok_prompt[] = "Old Password:";
48const char newauthtok_prompt[] = "New Password:";
49
50/*
51 * OpenPAM extension
52 *
53 * Retrieve authentication token
54 */
55
56int
57pam_get_authtok(pam_handle_t *pamh,
58	int item,
59	const char **authtok,
60	const char *prompt)
61{
62	const void *oldauthtok;
63	const char *default_prompt;
64	char *resp, *resp2;
65	int pitem, r, style, twice;
66
67	if (pamh == NULL || authtok == NULL)
68		return (PAM_SYSTEM_ERR);
69
70	*authtok = NULL;
71	twice = 0;
72	switch (item) {
73	case PAM_AUTHTOK:
74		pitem = PAM_AUTHTOK_PROMPT;
75		default_prompt = authtok_prompt;
76		r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok);
77		if (r == PAM_SUCCESS && oldauthtok != NULL) {
78			default_prompt = newauthtok_prompt;
79			twice = 1;
80		}
81		break;
82	case PAM_OLDAUTHTOK:
83		pitem = PAM_OLDAUTHTOK_PROMPT;
84		default_prompt = oldauthtok_prompt;
85		twice = 0;
86		break;
87	default:
88		return (PAM_SYMBOL_ERR);
89	}
90
91	if (openpam_get_option(pamh, "try_first_pass") ||
92	    openpam_get_option(pamh, "use_first_pass")) {
93		r = pam_get_item(pamh, item, (const void **)authtok);
94		if (r == PAM_SUCCESS && *authtok != NULL)
95			return (PAM_SUCCESS);
96		else if (openpam_get_option(pamh, "use_first_pass"))
97			return (r == PAM_SUCCESS ? PAM_AUTH_ERR : r);
98	}
99	if (prompt == NULL) {
100		r = pam_get_item(pamh, pitem, (const void **)&prompt);
101		if (r != PAM_SUCCESS || prompt == NULL)
102			prompt = default_prompt;
103	}
104	style = openpam_get_option(pamh, "echo_pass") ?
105	    PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF;
106	r = pam_prompt(pamh, style, &resp, "%s", prompt);
107	if (r != PAM_SUCCESS)
108		return (r);
109	if (twice) {
110		r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt);
111		if (r != PAM_SUCCESS) {
112			free(resp);
113			return (r);
114		}
115		if (strcmp(resp, resp2) != 0) {
116			free(resp);
117			resp = NULL;
118		}
119		free(resp2);
120	}
121	if (resp == NULL)
122		return (PAM_TRY_AGAIN);
123	r = pam_set_item(pamh, pitem, resp);
124	free(resp);
125	if (r != PAM_SUCCESS)
126		return (r);
127	return (pam_get_item(pamh, pitem, (const void **)authtok));
128}
129
130/*
131 * Error codes:
132 *
133 *	=pam_get_item
134 *	=pam_prompt
135 *	=pam_set_item
136 *	!PAM_SYMBOL_ERR
137 *	PAM_TRY_AGAIN
138 */
139
140/**
141 * The =pam_get_authtok function returns the cached authentication token,
142 * or prompts the user if no token is currently cached.  Either way, a
143 * pointer to the authentication token is stored in the location pointed
144 * to by the =authtok argument.
145 *
146 * The =item argument must have one of the following values:
147 *
148 *	=PAM_AUTHTOK
149 *		Returns the current authentication token, or the new token
150 *		when changing authentication tokens.
151 *	=PAM_OLDAUTHTOK
152 *		Returns the previous authentication token when changing
153 *		authentication tokens.
154 *
155 * The =prompt argument specifies a prompt to use if no token is cached.
156 * If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item,
157 * as appropriate, will be used.  If that item is also =NULL, a hardcoded
158 * default prompt will be used.
159 *
160 * If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK
161 * item, =pam_get_authtok will ask the user to confirm the new token by
162 * retyping it.  If there is a mismatch, =pam_get_authtok will return
163 * =PAM_TRY_AGAIN.
164 *
165 * >pam_get_item
166 * >pam_get_user
167 */
168