source: openpam/trunk/lib/libpam/pam_get_authtok.c @ 932

Last change on this file since 932 was 932, checked in by Dag-Erling Smørgrav, 4 years ago

Add two more error codes for situations where we used PAM_SYMBOL_ERR.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Id
File size: 7.7 KB
Line 
1/*-
2 * Copyright (c) 2002-2003 Networks Associates Technology, Inc.
3 * Copyright (c) 2004-2017 Dag-Erling Smørgrav
4 * All rights reserved.
5 *
6 * This software was developed for the FreeBSD Project by ThinkSec AS and
7 * Network Associates Laboratories, the Security Research Division of
8 * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
9 * ("CBOSS"), as part of the DARPA CHATS research program.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. The name of the author may not be used to endorse or promote
20 *    products derived from this software without specific prior written
21 *    permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 *
35 * $Id: pam_get_authtok.c 932 2017-04-26 20:41:59Z des $
36 */
37
38#ifdef HAVE_CONFIG_H
39# include "config.h"
40#endif
41
42#include <sys/param.h>
43
44#include <stdlib.h>
45#include <string.h>
46
47#include <security/pam_appl.h>
48#include <security/openpam.h>
49
50#include "openpam_impl.h"
51#include "openpam_strlset.h"
52
53static const char authtok_prompt[] = "Password:";
54static const char authtok_prompt_remote[] = "Password for %u@%h:";
55static const char oldauthtok_prompt[] = "Old Password:";
56static const char newauthtok_prompt[] = "New Password:";
57
58/*
59 * OpenPAM extension
60 *
61 * Retrieve authentication token
62 */
63
64int
65pam_get_authtok(pam_handle_t *pamh,
66        int item,
67        const char **authtok,
68        const char *prompt)
69{
70        char prompt_buf[1024];
71        size_t prompt_size;
72        const void *oldauthtok, *prevauthtok, *promptp;
73        const char *prompt_option, *default_prompt;
74        const void *lhost, *rhost;
75        char *resp, *resp2;
76        int pitem, r, style, twice;
77
78        ENTER();
79        *authtok = NULL;
80        twice = 0;
81        switch (item) {
82        case PAM_AUTHTOK:
83                pitem = PAM_AUTHTOK_PROMPT;
84                prompt_option = "authtok_prompt";
85                default_prompt = authtok_prompt;
86                r = pam_get_item(pamh, PAM_RHOST, &rhost);
87                if (r == PAM_SUCCESS && rhost != NULL) {
88                        r = pam_get_item(pamh, PAM_HOST, &lhost);
89                        if (r == PAM_SUCCESS && lhost != NULL) {
90                                if (strcmp(rhost, lhost) != 0)
91                                        default_prompt = authtok_prompt_remote;
92                        }
93                }
94                r = pam_get_item(pamh, PAM_OLDAUTHTOK, &oldauthtok);
95                if (r == PAM_SUCCESS && oldauthtok != NULL) {
96                        default_prompt = newauthtok_prompt;
97                        twice = 1;
98                }
99                break;
100        case PAM_OLDAUTHTOK:
101                pitem = PAM_OLDAUTHTOK_PROMPT;
102                prompt_option = "oldauthtok_prompt";
103                default_prompt = oldauthtok_prompt;
104                twice = 0;
105                break;
106        default:
107                RETURNC(PAM_BAD_CONSTANT);
108        }
109        if (openpam_get_option(pamh, "try_first_pass") ||
110            openpam_get_option(pamh, "use_first_pass")) {
111                r = pam_get_item(pamh, item, &prevauthtok);
112                if (r == PAM_SUCCESS && prevauthtok != NULL) {
113                        *authtok = prevauthtok;
114                        RETURNC(PAM_SUCCESS);
115                } else if (openpam_get_option(pamh, "use_first_pass")) {
116                        RETURNC(r == PAM_SUCCESS ? PAM_AUTH_ERR : r);
117                }
118        }
119        /* pam policy overrides the module's choice */
120        if ((promptp = openpam_get_option(pamh, prompt_option)) != NULL)
121                prompt = promptp;
122        /* no prompt provided, see if there is one tucked away somewhere */
123        if (prompt == NULL) {
124                r = pam_get_item(pamh, pitem, &promptp);
125                if (r == PAM_SUCCESS && promptp != NULL)
126                        prompt = promptp;
127        }
128        /* fall back to hardcoded default */
129        if (prompt == NULL)
130                prompt = default_prompt;
131        /* expand */
132        prompt_size = sizeof prompt_buf;
133        r = openpam_subst(pamh, prompt_buf, &prompt_size, prompt);
134        if (r == PAM_SUCCESS && prompt_size <= sizeof prompt_buf)
135                prompt = prompt_buf;
136        style = openpam_get_option(pamh, "echo_pass") ?
137            PAM_PROMPT_ECHO_ON : PAM_PROMPT_ECHO_OFF;
138        r = pam_prompt(pamh, style, &resp, "%s", prompt);
139        if (r != PAM_SUCCESS)
140                RETURNC(r);
141        if (twice) {
142                r = pam_prompt(pamh, style, &resp2, "Retype %s", prompt);
143                if (r != PAM_SUCCESS) {
144                        strlset(resp, 0, PAM_MAX_RESP_SIZE);
145                        FREE(resp);
146                        RETURNC(r);
147                }
148                if (strcmp(resp, resp2) != 0) {
149                        strlset(resp, 0, PAM_MAX_RESP_SIZE);
150                        FREE(resp);
151                }
152                strlset(resp2, 0, PAM_MAX_RESP_SIZE);
153                FREE(resp2);
154        }
155        if (resp == NULL)
156                RETURNC(PAM_TRY_AGAIN);
157        r = pam_set_item(pamh, item, resp);
158        strlset(resp, 0, PAM_MAX_RESP_SIZE);
159        FREE(resp);
160        if (r != PAM_SUCCESS)
161                RETURNC(r);
162        r = pam_get_item(pamh, item, (const void **)authtok);
163        RETURNC(r);
164}
165
166/*
167 * Error codes:
168 *
169 *      =pam_get_item
170 *      =pam_prompt
171 *      =pam_set_item
172 *      !PAM_SYMBOL_ERR
173 *      PAM_BAD_CONSTANT
174 *      PAM_TRY_AGAIN
175 */
176
177/**
178 * The =pam_get_authtok function either prompts the user for an
179 * authentication token or retrieves a cached authentication token,
180 * depending on circumstances.
181 * Either way, a pointer to the authentication token is stored in the
182 * location pointed to by the =authtok argument, and the corresponding PAM
183 * item is updated.
184 *
185 * The =item argument must have one of the following values:
186 *
187 *      =PAM_AUTHTOK:
188 *              Returns the current authentication token, or the new token
189 *              when changing authentication tokens.
190 *      =PAM_OLDAUTHTOK:
191 *              Returns the previous authentication token when changing
192 *              authentication tokens.
193 *
194 * The =prompt argument specifies a prompt to use if no token is cached.
195 * If it is =NULL, the =PAM_AUTHTOK_PROMPT or =PAM_OLDAUTHTOK_PROMPT item,
196 * as appropriate, will be used.
197 * If that item is also =NULL, a hardcoded default prompt will be used.
198 * Additionally, when =pam_get_authtok is called from a service module,
199 * the prompt may be affected by module options as described below.
200 * The prompt is then expanded using =openpam_subst before it is passed to
201 * the conversation function.
202 *
203 * If =item is set to =PAM_AUTHTOK and there is a non-null =PAM_OLDAUTHTOK
204 * item, =pam_get_authtok will ask the user to confirm the new token by
205 * retyping it.
206 * If there is a mismatch, =pam_get_authtok will return =PAM_TRY_AGAIN.
207 *
208 * MODULE OPTIONS
209 *
210 * When called by a service module, =pam_get_authtok will recognize the
211 * following module options:
212 *
213 *      ;authtok_prompt:
214 *              Prompt to use when =item is set to =PAM_AUTHTOK.
215 *              This option overrides both the =prompt argument and the
216 *              =PAM_AUTHTOK_PROMPT item.
217 *      ;echo_pass:
218 *              If the application's conversation function allows it, this
219 *              lets the user see what they are typing.
220 *              This should only be used for non-reusable authentication
221 *              tokens.
222 *      ;oldauthtok_prompt:
223 *              Prompt to use when =item is set to =PAM_OLDAUTHTOK.
224 *              This option overrides both the =prompt argument and the
225 *              =PAM_OLDAUTHTOK_PROMPT item.
226 *      ;try_first_pass:
227 *              If the requested item is non-null, return it without
228 *              prompting the user.
229 *              Typically, the service module will verify the token, and
230 *              if it does not match, clear the item before calling
231 *              =pam_get_authtok a second time.
232 *      ;use_first_pass:
233 *              Do not prompt the user at all; just return the cached
234 *              value, or =PAM_AUTH_ERR if there is none.
235 *
236 * >pam_conv
237 * >pam_get_item
238 * >pam_get_user
239 * >openpam_get_option
240 * >openpam_subst
241 */
Note: See TracBrowser for help on using the repository browser.