1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright 1998 Juniper Networks, Inc. 5 * All rights reserved. 6 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 7 * All rights reserved. 8 * 9 * Portions of this software was developed for the FreeBSD Project by 10 * ThinkSec AS and NAI Labs, the Security Research Division of Network 11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 12 * ("CBOSS"), as part of the DARPA CHATS research program. 13 * 14 * Redistribution and use in source and binary forms, with or without 15 * modification, are permitted provided that the following conditions 16 * are met: 17 * 1. Redistributions of source code must retain the above copyright 18 * notice, this list of conditions and the following disclaimer. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. The name of the author may not be used to endorse or promote 23 * products derived from this software without specific prior written 24 * permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 __FBSDID("$FreeBSD$"); 41 42 #include <sys/param.h> 43 #include <sys/socket.h> 44 #include <sys/time.h> 45 #include <netinet/in.h> 46 #include <arpa/inet.h> 47 48 #include <login_cap.h> 49 #include <netdb.h> 50 #include <pwd.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <stdio.h> 54 #include <syslog.h> 55 #include <time.h> 56 #include <unistd.h> 57 58 #include <libutil.h> 59 60 #ifdef YP 61 #include <ypclnt.h> 62 #endif 63 64 #define PAM_SM_AUTH 65 #define PAM_SM_ACCOUNT 66 #define PAM_SM_PASSWORD 67 68 #include <security/pam_appl.h> 69 #include <security/pam_modules.h> 70 #include <security/pam_mod_misc.h> 71 72 #define PASSWORD_HASH "md5" 73 #define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 74 #define SALTSIZE 32 75 76 #define LOCKED_PREFIX "*LOCKED*" 77 #define LOCKED_PREFIX_LEN (sizeof(LOCKED_PREFIX) - 1) 78 79 static void makesalt(char []); 80 81 static char password_hash[] = PASSWORD_HASH; 82 83 #define PAM_OPT_LOCAL_PASS "local_pass" 84 #define PAM_OPT_NIS_PASS "nis_pass" 85 86 /* 87 * authentication management 88 */ 89 PAM_EXTERN int 90 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 91 int argc __unused, const char *argv[] __unused) 92 { 93 login_cap_t *lc; 94 struct passwd *pwd; 95 int retval; 96 const char *pass, *user, *realpw, *prompt; 97 const char *emptypasswd = ""; 98 99 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) { 100 user = getlogin(); 101 } else { 102 retval = pam_get_user(pamh, &user, NULL); 103 if (retval != PAM_SUCCESS) 104 return (retval); 105 } 106 pwd = getpwnam(user); 107 108 PAM_LOG("Got user: %s", user); 109 110 if (pwd != NULL) { 111 PAM_LOG("Doing real authentication"); 112 realpw = pwd->pw_passwd; 113 if (realpw[0] == '\0') { 114 if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) && 115 openpam_get_option(pamh, PAM_OPT_NULLOK)) 116 return (PAM_SUCCESS); 117 PAM_LOG("Password is empty, using fake password"); 118 realpw = "*"; 119 } 120 /* 121 * Check whether the saved password hash matches the one 122 * generated from an empty password - as opposed to empty 123 * saved password hash, which is handled above. 124 */ 125 if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) && 126 openpam_get_option(pamh, PAM_OPT_EMPTYOK) && 127 strcmp(crypt(emptypasswd, realpw), realpw) == 0) 128 return (PAM_SUCCESS); 129 lc = login_getpwclass(pwd); 130 } else { 131 PAM_LOG("Doing dummy authentication"); 132 realpw = "*"; 133 lc = login_getclass(NULL); 134 } 135 prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL); 136 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt); 137 login_close(lc); 138 if (retval != PAM_SUCCESS) 139 return (retval); 140 PAM_LOG("Got password"); 141 if (strnlen(pass, _PASSWORD_LEN + 1) > _PASSWORD_LEN) { 142 PAM_LOG("Password is too long, using fake password"); 143 realpw = "*"; 144 } 145 if (strcmp(crypt(pass, realpw), realpw) == 0) 146 return (PAM_SUCCESS); 147 148 PAM_VERBOSE_ERROR("UNIX authentication refused"); 149 return (PAM_AUTH_ERR); 150 } 151 152 PAM_EXTERN int 153 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused, 154 int argc __unused, const char *argv[] __unused) 155 { 156 157 return (PAM_SUCCESS); 158 } 159 160 /* 161 * account management 162 */ 163 PAM_EXTERN int 164 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 165 int argc __unused, const char *argv[] __unused) 166 { 167 struct addrinfo hints, *res; 168 struct passwd *pwd; 169 struct timeval tp; 170 login_cap_t *lc; 171 time_t warntime; 172 int retval; 173 const char *user; 174 const void *rhost, *tty; 175 char rhostip[MAXHOSTNAMELEN] = ""; 176 177 retval = pam_get_user(pamh, &user, NULL); 178 if (retval != PAM_SUCCESS) 179 return (retval); 180 181 if (user == NULL || (pwd = getpwnam(user)) == NULL) 182 return (PAM_SERVICE_ERR); 183 184 PAM_LOG("Got user: %s", user); 185 186 retval = pam_get_item(pamh, PAM_RHOST, &rhost); 187 if (retval != PAM_SUCCESS) 188 return (retval); 189 190 retval = pam_get_item(pamh, PAM_TTY, &tty); 191 if (retval != PAM_SUCCESS) 192 return (retval); 193 194 if (*pwd->pw_passwd == '\0' && 195 (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0) 196 return (PAM_NEW_AUTHTOK_REQD); 197 198 if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0) 199 return (PAM_AUTH_ERR); 200 201 lc = login_getpwclass(pwd); 202 if (lc == NULL) { 203 PAM_LOG("Unable to get login class for user %s", user); 204 return (PAM_SERVICE_ERR); 205 } 206 207 PAM_LOG("Got login_cap"); 208 209 if (pwd->pw_change || pwd->pw_expire) 210 gettimeofday(&tp, NULL); 211 212 /* 213 * Check pw_expire before pw_change - no point in letting the 214 * user change the password on an expired account. 215 */ 216 217 if (pwd->pw_expire) { 218 warntime = login_getcaptime(lc, "warnexpire", 219 DEFAULT_WARN, DEFAULT_WARN); 220 if (tp.tv_sec >= pwd->pw_expire) { 221 login_close(lc); 222 return (PAM_ACCT_EXPIRED); 223 } else if (pwd->pw_expire - tp.tv_sec < warntime && 224 (flags & PAM_SILENT) == 0) { 225 pam_error(pamh, "Warning: your account expires on %s", 226 ctime(&pwd->pw_expire)); 227 } 228 } 229 230 retval = PAM_SUCCESS; 231 if (pwd->pw_change) { 232 warntime = login_getcaptime(lc, "warnpassword", 233 DEFAULT_WARN, DEFAULT_WARN); 234 if (tp.tv_sec >= pwd->pw_change) { 235 retval = PAM_NEW_AUTHTOK_REQD; 236 } else if (pwd->pw_change - tp.tv_sec < warntime && 237 (flags & PAM_SILENT) == 0) { 238 pam_error(pamh, "Warning: your password expires on %s", 239 ctime(&pwd->pw_change)); 240 } 241 } 242 243 /* 244 * From here on, we must leave retval untouched (unless we 245 * know we're going to fail), because we need to remember 246 * whether we're supposed to return PAM_SUCCESS or 247 * PAM_NEW_AUTHTOK_REQD. 248 */ 249 250 if (rhost && *(const char *)rhost != '\0') { 251 memset(&hints, 0, sizeof(hints)); 252 hints.ai_family = AF_UNSPEC; 253 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) { 254 getnameinfo(res->ai_addr, res->ai_addrlen, 255 rhostip, sizeof(rhostip), NULL, 0, 256 NI_NUMERICHOST); 257 } 258 if (res != NULL) 259 freeaddrinfo(res); 260 } 261 262 /* 263 * Check host / tty / time-of-day restrictions 264 */ 265 266 if (!auth_hostok(lc, rhost, rhostip) || 267 !auth_ttyok(lc, tty) || 268 !auth_timeok(lc, time(NULL))) 269 retval = PAM_AUTH_ERR; 270 271 login_close(lc); 272 273 return (retval); 274 } 275 276 /* 277 * password management 278 * 279 * standard Unix and NIS password changing 280 */ 281 PAM_EXTERN int 282 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 283 int argc __unused, const char *argv[] __unused) 284 { 285 #ifdef YP 286 struct ypclnt *ypclnt; 287 const void *yp_domain, *yp_server; 288 #endif 289 char salt[SALTSIZE + 1]; 290 login_cap_t *lc; 291 struct passwd *pwd, *old_pwd; 292 const char *user, *old_pass, *new_pass; 293 char *encrypted; 294 time_t passwordtime; 295 int pfd, tfd, retval; 296 297 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 298 user = getlogin(); 299 else { 300 retval = pam_get_user(pamh, &user, NULL); 301 if (retval != PAM_SUCCESS) 302 return (retval); 303 } 304 pwd = getpwnam(user); 305 306 if (pwd == NULL) 307 return (PAM_AUTHTOK_RECOVERY_ERR); 308 309 PAM_LOG("Got user: %s", user); 310 311 if (flags & PAM_PRELIM_CHECK) { 312 313 PAM_LOG("PRELIM round"); 314 315 if (getuid() == 0 && 316 (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES) 317 /* root doesn't need the old password */ 318 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 319 #ifdef YP 320 if (getuid() == 0 && 321 (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS) { 322 323 yp_domain = yp_server = NULL; 324 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 325 (void)pam_get_data(pamh, "yp_server", &yp_server); 326 327 ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server); 328 if (ypclnt == NULL) 329 return (PAM_BUF_ERR); 330 331 if (ypclnt_connect(ypclnt) == -1) { 332 ypclnt_free(ypclnt); 333 return (PAM_SERVICE_ERR); 334 } 335 336 retval = ypclnt_havepasswdd(ypclnt); 337 ypclnt_free(ypclnt); 338 if (retval == 1) 339 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 340 else if (retval == -1) 341 return (PAM_SERVICE_ERR); 342 } 343 #endif 344 if (pwd->pw_passwd[0] == '\0' 345 && openpam_get_option(pamh, PAM_OPT_NULLOK)) { 346 /* 347 * No password case. XXX Are we giving too much away 348 * by not prompting for a password? 349 * XXX check PAM_DISALLOW_NULL_AUTHTOK 350 */ 351 old_pass = ""; 352 retval = PAM_SUCCESS; 353 } else { 354 retval = pam_get_authtok(pamh, 355 PAM_OLDAUTHTOK, &old_pass, NULL); 356 if (retval != PAM_SUCCESS) 357 return (retval); 358 } 359 PAM_LOG("Got old password"); 360 /* always encrypt first */ 361 encrypted = crypt(old_pass, pwd->pw_passwd); 362 if (old_pass[0] == '\0' && 363 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 364 return (PAM_PERM_DENIED); 365 if (strcmp(encrypted, pwd->pw_passwd) != 0) 366 return (PAM_PERM_DENIED); 367 } 368 else if (flags & PAM_UPDATE_AUTHTOK) { 369 PAM_LOG("UPDATE round"); 370 371 retval = pam_get_authtok(pamh, 372 PAM_OLDAUTHTOK, &old_pass, NULL); 373 if (retval != PAM_SUCCESS) 374 return (retval); 375 PAM_LOG("Got old password"); 376 377 /* get new password */ 378 for (;;) { 379 retval = pam_get_authtok(pamh, 380 PAM_AUTHTOK, &new_pass, NULL); 381 if (retval != PAM_TRY_AGAIN) 382 break; 383 pam_error(pamh, "Mismatch; try again, EOF to quit."); 384 } 385 PAM_LOG("Got new password"); 386 if (retval != PAM_SUCCESS) { 387 PAM_VERBOSE_ERROR("Unable to get new password"); 388 return (retval); 389 } 390 391 if (getuid() != 0 && new_pass[0] == '\0' && 392 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 393 return (PAM_PERM_DENIED); 394 395 if ((old_pwd = pw_dup(pwd)) == NULL) 396 return (PAM_BUF_ERR); 397 398 lc = login_getclass(pwd->pw_class); 399 if (login_setcryptfmt(lc, password_hash, NULL) == NULL) 400 openpam_log(PAM_LOG_ERROR, 401 "can't set password cipher, relying on default"); 402 403 /* set password expiry date */ 404 pwd->pw_change = 0; 405 passwordtime = login_getcaptime(lc, "passwordtime", 0, 0); 406 if (passwordtime > 0) 407 pwd->pw_change = time(NULL) + passwordtime; 408 409 login_close(lc); 410 makesalt(salt); 411 pwd->pw_passwd = crypt(new_pass, salt); 412 #ifdef YP 413 switch (old_pwd->pw_fields & _PWF_SOURCE) { 414 case _PWF_FILES: 415 #endif 416 retval = PAM_SERVICE_ERR; 417 if (pw_init(NULL, NULL)) 418 openpam_log(PAM_LOG_ERROR, "pw_init() failed"); 419 else if ((pfd = pw_lock()) == -1) 420 openpam_log(PAM_LOG_ERROR, "pw_lock() failed"); 421 else if ((tfd = pw_tmp(-1)) == -1) 422 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed"); 423 else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1) 424 openpam_log(PAM_LOG_ERROR, "pw_copy() failed"); 425 else if (pw_mkdb(pwd->pw_name) == -1) 426 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed"); 427 else 428 retval = PAM_SUCCESS; 429 pw_fini(); 430 #ifdef YP 431 break; 432 case _PWF_NIS: 433 yp_domain = yp_server = NULL; 434 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 435 (void)pam_get_data(pamh, "yp_server", &yp_server); 436 ypclnt = ypclnt_new(yp_domain, 437 "passwd.byname", yp_server); 438 if (ypclnt == NULL) { 439 retval = PAM_BUF_ERR; 440 } else if (ypclnt_connect(ypclnt) == -1 || 441 ypclnt_passwd(ypclnt, pwd, old_pass) == -1) { 442 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error); 443 retval = PAM_SERVICE_ERR; 444 } else { 445 retval = PAM_SUCCESS; 446 } 447 ypclnt_free(ypclnt); 448 break; 449 default: 450 openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x", 451 pwd->pw_fields & _PWF_SOURCE); 452 retval = PAM_SERVICE_ERR; 453 } 454 #endif 455 free(old_pwd); 456 } 457 else { 458 /* Very bad juju */ 459 retval = PAM_ABORT; 460 PAM_LOG("Illegal 'flags'"); 461 } 462 463 return (retval); 464 } 465 466 /* Mostly stolen from passwd(1)'s local_passwd.c - markm */ 467 468 static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */ 469 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 470 471 static void 472 to64(char *s, long v, int n) 473 { 474 while (--n >= 0) { 475 *s++ = itoa64[v&0x3f]; 476 v >>= 6; 477 } 478 } 479 480 /* Salt suitable for traditional DES and MD5 */ 481 static void 482 makesalt(char salt[SALTSIZE + 1]) 483 { 484 int i; 485 486 /* These are not really random numbers, they are just 487 * numbers that change to thwart construction of a 488 * dictionary. 489 */ 490 for (i = 0; i < SALTSIZE; i += 4) 491 to64(&salt[i], arc4random(), 4); 492 salt[SALTSIZE] = '\0'; 493 } 494 495 PAM_MODULE_ENTRY("pam_unix"); 496