xref: /illumos-gate/usr/src/lib/pam_modules/passwd_auth/passwd_auth.c (revision 068cf9dc70b00292d5e5ff1ab17f1b046215d6f6)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
26  */
27 
28 #include <sys/types.h>
29 #include <sys/varargs.h>
30 #include <string.h>
31 #include <stdlib.h>
32 #include <syslog.h>
33 #include <unistd.h>
34 #include <crypt.h>
35 #include <pwd.h>
36 #include <libintl.h>
37 
38 #include <security/pam_appl.h>
39 #include <security/pam_modules.h>
40 #include <security/pam_impl.h>
41 
42 #include <passwdutil.h>
43 
44 #include <sys/note.h>
45 
46 /*PRINTFLIKE3*/
47 void
48 error(int nowarn, pam_handle_t *pamh, char *fmt, ...)
49 {
50 	va_list ap;
51 	char messages[PAM_MAX_NUM_MSG][PAM_MAX_MSG_SIZE];
52 
53 	va_start(ap, fmt);
54 	(void) vsnprintf(messages[0], sizeof (messages[0]), fmt, ap);
55 	if (nowarn == 0)
56 		(void) __pam_display_msg(pamh, PAM_ERROR_MSG, 1, messages,
57 		    NULL);
58 	va_end(ap);
59 }
60 
61 /*
62  * int pam_sm_authenticate(pamh, flags, argc, argv)
63  *
64  * Read authentication token from user.
65  */
66 int
67 pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc, const char **argv)
68 {
69 
70 	const char *user;
71 	char *password;
72 	const char *service;
73 	int i;
74 	int debug = 0;
75 	int nowarn = 0;
76 	int res;
77 	char prompt[PAM_MAX_MSG_SIZE];
78 	char *auth_user = NULL;
79 	int retval;
80 	int privileged;
81 	char *rep_passwd = NULL;
82 	char *repository_name = NULL;
83 	attrlist al[8];
84 	int min;
85 	int max;
86 	int lstchg;
87 	int server_policy = 0;
88 
89 	const pam_repository_t *auth_rep = NULL;
90 	pwu_repository_t *pwu_rep = NULL;
91 
92 	for (i = 0; i < argc; i++) {
93 		if (strcmp(argv[i], "debug") == 0)
94 			debug = 1;
95 		if (strcmp(argv[i], "nowarn") == 0)
96 			nowarn = 1;
97 		if (strcmp(argv[i], "server_policy") == 0)
98 			server_policy = 1;
99 	}
100 
101 	if (flags & PAM_SILENT)
102 		nowarn = 1;
103 
104 	if ((res = pam_get_user(pamh, (const char **)&user, NULL)) !=
105 	    PAM_SUCCESS) {
106 		if (debug)
107 			syslog(LOG_DEBUG, "pam_passwd_auth: "
108 			    "get user failed: %s", pam_strerror(pamh, res));
109 		return (res);
110 	}
111 
112 	if (user == NULL || *user == '\0') {
113 		syslog(LOG_ERR, "pam_passwd_auth: pam_sm_authenticate: "
114 		    "PAM_USER NULL or empty");
115 		return (PAM_SYSTEM_ERR);
116 	}
117 
118 	res = pam_get_item(pamh, PAM_AUTHTOK, (const void **)&password);
119 	if (res != PAM_SUCCESS)
120 		return (res);
121 
122 	if (password != NULL)
123 		return (PAM_IGNORE);
124 
125 	res = pam_get_item(pamh, PAM_SERVICE, (const void **)&service);
126 	if (res != PAM_SUCCESS)
127 		return (res);
128 
129 	res = pam_get_item(pamh, PAM_REPOSITORY, (const void **)&auth_rep);
130 	if (res != PAM_SUCCESS) {
131 		syslog(LOG_ERR, "pam_passwd_auth: pam_sm_authenticate: "
132 		    "error getting repository");
133 		return (PAM_SYSTEM_ERR);
134 	}
135 
136 	if (auth_rep == NULL) {
137 		pwu_rep = PWU_DEFAULT_REP;
138 	} else {
139 		if ((pwu_rep = calloc(1, sizeof (*pwu_rep))) == NULL)
140 			return (PAM_BUF_ERR);
141 		pwu_rep->type = auth_rep->type;
142 		pwu_rep->scope = auth_rep->scope;
143 		pwu_rep->scope_len = auth_rep->scope_len;
144 	}
145 
146 	res = __user_to_authenticate(user, pwu_rep, &auth_user, &privileged);
147 	if (res != PWU_SUCCESS) {
148 		if (res == PWU_NOT_FOUND)
149 			retval = PAM_USER_UNKNOWN;
150 		else if (res == PWU_DENIED)
151 			retval = PAM_PERM_DENIED;
152 		else if (res == PWU_REPOSITORY_ERROR) {
153 			syslog(LOG_NOTICE,
154 			    "pam_passwd_auth: detected unsupported "
155 			    "configuration in /etc/nsswitch.conf.");
156 			error(nowarn, pamh, dgettext(TEXT_DOMAIN, "%s: "
157 			    "Unsupported nsswitch entry for \"passwd:\"."
158 			    " Use \"-r repository \"."), service);
159 			retval = PAM_SYSTEM_ERR;
160 		} else
161 			retval = PAM_SYSTEM_ERR;
162 		if (debug)
163 			syslog(LOG_DEBUG, "passwd_auth: __user_to_authenticate "
164 			    "returned %d", retval);
165 		goto out;
166 	}
167 
168 	if (auth_user == NULL) {		/* No authentication needed */
169 		if (debug)
170 			syslog(LOG_DEBUG,
171 			    "passwd_auth: no authentication needed.");
172 		retval = PAM_SUCCESS;
173 		goto out;
174 	}
175 
176 	/*
177 	 * The password prompt differs between users updating their
178 	 * own password, and users updating other an user's password
179 	 */
180 	if (privileged) {
181 		/*
182 		 * TRANSLATION_NOTE
183 		 * The following string has a single space at the end
184 		 */
185 		(void) snprintf(prompt, sizeof (prompt),
186 		    dgettext(TEXT_DOMAIN, "Enter %s's password: "),
187 		    auth_user);
188 	} else {
189 		/*
190 		 * TRANSLATION_NOTE
191 		 * The following string has a single space at the end
192 		 */
193 		(void) snprintf(prompt, sizeof (prompt),
194 		    dgettext(TEXT_DOMAIN, "Enter existing login password: "));
195 	}
196 
197 	retval = __pam_get_authtok(pamh, PAM_PROMPT, PAM_AUTHTOK, prompt,
198 	    &password);
199 	if (retval != PAM_SUCCESS)
200 		goto out;
201 
202 	if (password == NULL) {
203 		syslog(LOG_ERR, "pam_passwd_auth: pam_sm_authenticate: "
204 		    "got NULL password from get_authtok()");
205 		retval = PAM_AUTH_ERR;
206 		goto out;
207 	}
208 
209 	/* Privileged users can skip the tests that follow */
210 	if (privileged)
211 		goto setitem;
212 
213 	/*
214 	 * Non privileged user: so we need to check the old password
215 	 * and possible restrictions on password changes.
216 	 */
217 
218 	/* Get password and it's age from the repository specified */
219 	al[0].type = ATTR_PASSWD; al[0].next = &al[1];
220 	al[1].type = ATTR_MIN; al[1].next = &al[2];
221 	al[2].type = ATTR_MAX; al[2].next = &al[3];
222 	al[3].type = ATTR_LSTCHG; al[3].next = &al[4];
223 	al[4].type = ATTR_WARN; al[4].next = &al[5];
224 	al[5].type = ATTR_INACT; al[5].next = &al[6];
225 	al[6].type = ATTR_EXPIRE; al[6].next = &al[7];
226 	al[7].type = ATTR_REP_NAME; al[7].next = NULL;
227 
228 	res = __get_authtoken_attr(auth_user, pwu_rep, al);
229 
230 	if (res != PWU_SUCCESS) {
231 		retval = PAM_SYSTEM_ERR;
232 		goto out;
233 	}
234 
235 	repository_name = al[7].data.val_s;
236 
237 	/*
238 	 * if repository isn't files|nis, and user wants to follow server
239 	 * policy, return PAM_IGNORE
240 	 */
241 	if (server_policy &&
242 	    strcmp(repository_name, "files") != 0 &&
243 	    strcmp(repository_name, "nis") != 0) {
244 		retval = PAM_IGNORE;
245 		goto out;
246 	}
247 
248 	rep_passwd = al[0].data.val_s;
249 
250 	/*
251 	 * Chop off old SunOS-style password aging information.
252 	 *
253 	 * Note: old style password aging is only defined for UNIX-style
254 	 *	 crypt strings, hence the comma will always be at position 14.
255 	 * Note: This code is here because some other vendors might still
256 	 *	 support this style of password aging. If we don't remove
257 	 *	 the age field, users won't be able to change their password.
258 	 * XXX   yank this code when we're certain this "compatibility"
259 	 *	 isn't needed anymore.
260 	 */
261 	if (rep_passwd != NULL && rep_passwd[0] != '$' &&
262 	    strlen(rep_passwd) > 13 && rep_passwd[13] == ',')
263 		rep_passwd[13] = '\0';
264 
265 	if (strcmp(crypt(password, rep_passwd), rep_passwd) != 0) {
266 		retval = PAM_AUTH_ERR;
267 		goto out;
268 	}
269 
270 	/*
271 	 * Now check to see if the user is allowed to change
272 	 * the password.
273 	 */
274 	min = al[1].data.val_i;
275 	max = al[2].data.val_i;
276 	lstchg = al[3].data.val_i;
277 
278 	if (max != -1 && lstchg != 0) {
279 		/* aging is turned on, and a change is not forced */
280 		time_t daynow = DAY_NOW_32;
281 		if ((time_t)lstchg <= daynow) {
282 			/* Aged enough? */
283 			if (daynow < (time_t)(lstchg + min)) {
284 				error(nowarn, pamh, dgettext(TEXT_DOMAIN,
285 				    "%s: Sorry: less than %d days "
286 				    "since the last change."),
287 				    service, min);
288 				retval = PAM_PERM_DENIED;
289 				goto out;
290 			}
291 
292 			/*
293 			 * users with min>max are not allowed to
294 			 * change their password.
295 			 */
296 			if (min > max) {
297 				error(nowarn, pamh, dgettext(TEXT_DOMAIN,
298 				    "%s: You may not change "
299 				    "this password."), service);
300 				retval = PAM_PERM_DENIED;
301 				goto out;
302 			}
303 		}
304 	}
305 
306 setitem:
307 
308 	retval = pam_set_item(pamh, PAM_AUTHTOK, (void *)password);
309 
310 out:
311 	if (password) {
312 		(void) memset(password, 0, strlen(password));
313 		free(password);
314 	}
315 	if (rep_passwd) {
316 		(void) memset(rep_passwd, 0, strlen(rep_passwd));
317 		free(rep_passwd);
318 	}
319 	if (pwu_rep)
320 		free(pwu_rep);
321 	if (auth_user)
322 		free(auth_user);
323 	if (repository_name)
324 		free(repository_name);
325 
326 	return (retval);
327 }
328 
329 /*ARGSUSED*/
330 int
331 pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv)
332 {
333 	return (PAM_IGNORE);
334 }
335