pam_unix.c revision 300453
1/*- 2 * Copyright 1998 Juniper Networks, Inc. 3 * All rights reserved. 4 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 5 * All rights reserved. 6 * 7 * Portions of this software was developed for the FreeBSD Project by 8 * ThinkSec AS and NAI Labs, the Security Research Division of Network 9 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 10 * ("CBOSS"), as part of the DARPA CHATS research program. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. The name of the author may not be used to endorse or promote 21 * products derived from this software without specific prior written 22 * permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#include <sys/cdefs.h> 38__FBSDID("$FreeBSD: stable/10/lib/libpam/modules/pam_unix/pam_unix.c 300453 2016-05-23 05:11:08Z truckman $"); 39 40#include <sys/param.h> 41#include <sys/socket.h> 42#include <sys/time.h> 43#include <netinet/in.h> 44#include <arpa/inet.h> 45 46#include <login_cap.h> 47#include <netdb.h> 48#include <pwd.h> 49#include <stdlib.h> 50#include <string.h> 51#include <stdio.h> 52#include <syslog.h> 53#include <time.h> 54#include <unistd.h> 55 56#include <libutil.h> 57 58#ifdef YP 59#include <ypclnt.h> 60#endif 61 62#define PAM_SM_AUTH 63#define PAM_SM_ACCOUNT 64#define PAM_SM_PASSWORD 65 66#include <security/pam_appl.h> 67#include <security/pam_modules.h> 68#include <security/pam_mod_misc.h> 69 70#define PASSWORD_HASH "md5" 71#define DEFAULT_WARN (2L * 7L * 86400L) /* Two weeks */ 72#define SALTSIZE 32 73 74#define LOCKED_PREFIX "*LOCKED*" 75#define LOCKED_PREFIX_LEN (sizeof(LOCKED_PREFIX) - 1) 76 77static void makesalt(char []); 78 79static char password_hash[] = PASSWORD_HASH; 80 81#define PAM_OPT_LOCAL_PASS "local_pass" 82#define PAM_OPT_NIS_PASS "nis_pass" 83 84/* 85 * authentication management 86 */ 87PAM_EXTERN int 88pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 89 int argc __unused, const char *argv[] __unused) 90{ 91 login_cap_t *lc; 92 struct passwd *pwd; 93 int retval; 94 const char *pass, *user, *realpw, *prompt; 95 96 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) { 97 user = getlogin(); 98 } else { 99 retval = pam_get_user(pamh, &user, NULL); 100 if (retval != PAM_SUCCESS) 101 return (retval); 102 } 103 pwd = getpwnam(user); 104 105 PAM_LOG("Got user: %s", user); 106 107 if (pwd != NULL) { 108 PAM_LOG("Doing real authentication"); 109 realpw = pwd->pw_passwd; 110 if (realpw[0] == '\0') { 111 if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) && 112 openpam_get_option(pamh, PAM_OPT_NULLOK)) 113 return (PAM_SUCCESS); 114 realpw = "*"; 115 } 116 lc = login_getpwclass(pwd); 117 } else { 118 PAM_LOG("Doing dummy authentication"); 119 realpw = "*"; 120 lc = login_getclass(NULL); 121 } 122 prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL); 123 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt); 124 login_close(lc); 125 if (retval != PAM_SUCCESS) 126 return (retval); 127 PAM_LOG("Got password"); 128 if (strcmp(crypt(pass, realpw), realpw) == 0) 129 return (PAM_SUCCESS); 130 131 PAM_VERBOSE_ERROR("UNIX authentication refused"); 132 return (PAM_AUTH_ERR); 133} 134 135PAM_EXTERN int 136pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused, 137 int argc __unused, const char *argv[] __unused) 138{ 139 140 return (PAM_SUCCESS); 141} 142 143/* 144 * account management 145 */ 146PAM_EXTERN int 147pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 148 int argc __unused, const char *argv[] __unused) 149{ 150 struct addrinfo hints, *res; 151 struct passwd *pwd; 152 struct timeval tp; 153 login_cap_t *lc; 154 time_t warntime; 155 int retval; 156 const char *user; 157 const void *rhost, *tty; 158 char rhostip[MAXHOSTNAMELEN] = ""; 159 160 retval = pam_get_user(pamh, &user, NULL); 161 if (retval != PAM_SUCCESS) 162 return (retval); 163 164 if (user == NULL || (pwd = getpwnam(user)) == NULL) 165 return (PAM_SERVICE_ERR); 166 167 PAM_LOG("Got user: %s", user); 168 169 retval = pam_get_item(pamh, PAM_RHOST, &rhost); 170 if (retval != PAM_SUCCESS) 171 return (retval); 172 173 retval = pam_get_item(pamh, PAM_TTY, &tty); 174 if (retval != PAM_SUCCESS) 175 return (retval); 176 177 if (*pwd->pw_passwd == '\0' && 178 (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0) 179 return (PAM_NEW_AUTHTOK_REQD); 180 181 if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0) 182 return (PAM_AUTH_ERR); 183 184 lc = login_getpwclass(pwd); 185 if (lc == NULL) { 186 PAM_LOG("Unable to get login class for user %s", user); 187 return (PAM_SERVICE_ERR); 188 } 189 190 PAM_LOG("Got login_cap"); 191 192 if (pwd->pw_change || pwd->pw_expire) 193 gettimeofday(&tp, NULL); 194 195 /* 196 * Check pw_expire before pw_change - no point in letting the 197 * user change the password on an expired account. 198 */ 199 200 if (pwd->pw_expire) { 201 warntime = login_getcaptime(lc, "warnexpire", 202 DEFAULT_WARN, DEFAULT_WARN); 203 if (tp.tv_sec >= pwd->pw_expire) { 204 login_close(lc); 205 return (PAM_ACCT_EXPIRED); 206 } else if (pwd->pw_expire - tp.tv_sec < warntime && 207 (flags & PAM_SILENT) == 0) { 208 pam_error(pamh, "Warning: your account expires on %s", 209 ctime(&pwd->pw_expire)); 210 } 211 } 212 213 retval = PAM_SUCCESS; 214 if (pwd->pw_change) { 215 warntime = login_getcaptime(lc, "warnpassword", 216 DEFAULT_WARN, DEFAULT_WARN); 217 if (tp.tv_sec >= pwd->pw_change) { 218 retval = PAM_NEW_AUTHTOK_REQD; 219 } else if (pwd->pw_change - tp.tv_sec < warntime && 220 (flags & PAM_SILENT) == 0) { 221 pam_error(pamh, "Warning: your password expires on %s", 222 ctime(&pwd->pw_change)); 223 } 224 } 225 226 /* 227 * From here on, we must leave retval untouched (unless we 228 * know we're going to fail), because we need to remember 229 * whether we're supposed to return PAM_SUCCESS or 230 * PAM_NEW_AUTHTOK_REQD. 231 */ 232 233 if (rhost && *(const char *)rhost != '\0') { 234 memset(&hints, 0, sizeof(hints)); 235 hints.ai_family = AF_UNSPEC; 236 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) { 237 getnameinfo(res->ai_addr, res->ai_addrlen, 238 rhostip, sizeof(rhostip), NULL, 0, 239 NI_NUMERICHOST); 240 } 241 if (res != NULL) 242 freeaddrinfo(res); 243 } 244 245 /* 246 * Check host / tty / time-of-day restrictions 247 */ 248 249 if (!auth_hostok(lc, rhost, rhostip) || 250 !auth_ttyok(lc, tty) || 251 !auth_timeok(lc, time(NULL))) 252 retval = PAM_AUTH_ERR; 253 254 login_close(lc); 255 256 return (retval); 257} 258 259/* 260 * password management 261 * 262 * standard Unix and NIS password changing 263 */ 264PAM_EXTERN int 265pam_sm_chauthtok(pam_handle_t *pamh, int flags, 266 int argc __unused, const char *argv[] __unused) 267{ 268#ifdef YP 269 struct ypclnt *ypclnt; 270 const void *yp_domain, *yp_server; 271#endif 272 char salt[SALTSIZE + 1]; 273 login_cap_t *lc; 274 struct passwd *pwd, *old_pwd; 275 const char *user, *old_pass, *new_pass; 276 char *encrypted; 277 time_t passwordtime; 278 int pfd, tfd, retval; 279 280 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 281 user = getlogin(); 282 else { 283 retval = pam_get_user(pamh, &user, NULL); 284 if (retval != PAM_SUCCESS) 285 return (retval); 286 } 287 pwd = getpwnam(user); 288 289 if (pwd == NULL) 290 return (PAM_AUTHTOK_RECOVERY_ERR); 291 292 PAM_LOG("Got user: %s", user); 293 294 if (flags & PAM_PRELIM_CHECK) { 295 296 PAM_LOG("PRELIM round"); 297 298 if (getuid() == 0 && 299 (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES) 300 /* root doesn't need the old password */ 301 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 302#ifdef YP 303 if (getuid() == 0 && 304 (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS) { 305 306 yp_domain = yp_server = NULL; 307 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 308 (void)pam_get_data(pamh, "yp_server", &yp_server); 309 310 ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server); 311 if (ypclnt == NULL) 312 return (PAM_BUF_ERR); 313 314 if (ypclnt_connect(ypclnt) == -1) { 315 ypclnt_free(ypclnt); 316 return (PAM_SERVICE_ERR); 317 } 318 319 retval = ypclnt_havepasswdd(ypclnt); 320 ypclnt_free(ypclnt); 321 if (retval == 1) 322 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 323 else if (retval == -1) 324 return (PAM_SERVICE_ERR); 325 } 326#endif 327 if (pwd->pw_passwd[0] == '\0' 328 && openpam_get_option(pamh, PAM_OPT_NULLOK)) { 329 /* 330 * No password case. XXX Are we giving too much away 331 * by not prompting for a password? 332 * XXX check PAM_DISALLOW_NULL_AUTHTOK 333 */ 334 old_pass = ""; 335 } else { 336 retval = pam_get_authtok(pamh, 337 PAM_OLDAUTHTOK, &old_pass, NULL); 338 if (retval != PAM_SUCCESS) 339 return (retval); 340 } 341 PAM_LOG("Got old password"); 342 /* always encrypt first */ 343 encrypted = crypt(old_pass, pwd->pw_passwd); 344 if (old_pass[0] == '\0' && 345 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 346 return (PAM_PERM_DENIED); 347 if (strcmp(encrypted, pwd->pw_passwd) != 0) 348 return (PAM_PERM_DENIED); 349 } 350 else if (flags & PAM_UPDATE_AUTHTOK) { 351 PAM_LOG("UPDATE round"); 352 353 retval = pam_get_authtok(pamh, 354 PAM_OLDAUTHTOK, &old_pass, NULL); 355 if (retval != PAM_SUCCESS) 356 return (retval); 357 PAM_LOG("Got old password"); 358 359 /* get new password */ 360 for (;;) { 361 retval = pam_get_authtok(pamh, 362 PAM_AUTHTOK, &new_pass, NULL); 363 if (retval != PAM_TRY_AGAIN) 364 break; 365 pam_error(pamh, "Mismatch; try again, EOF to quit."); 366 } 367 PAM_LOG("Got new password"); 368 if (retval != PAM_SUCCESS) { 369 PAM_VERBOSE_ERROR("Unable to get new password"); 370 return (retval); 371 } 372 373 if (getuid() != 0 && new_pass[0] == '\0' && 374 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 375 return (PAM_PERM_DENIED); 376 377 if ((old_pwd = pw_dup(pwd)) == NULL) 378 return (PAM_BUF_ERR); 379 380 lc = login_getclass(pwd->pw_class); 381 if (login_setcryptfmt(lc, password_hash, NULL) == NULL) 382 openpam_log(PAM_LOG_ERROR, 383 "can't set password cipher, relying on default"); 384 385 /* set password expiry date */ 386 pwd->pw_change = 0; 387 passwordtime = login_getcaptime(lc, "passwordtime", 0, 0); 388 if (passwordtime > 0) 389 pwd->pw_change = time(NULL) + passwordtime; 390 391 login_close(lc); 392 makesalt(salt); 393 pwd->pw_passwd = crypt(new_pass, salt); 394#ifdef YP 395 switch (old_pwd->pw_fields & _PWF_SOURCE) { 396 case _PWF_FILES: 397#endif 398 retval = PAM_SERVICE_ERR; 399 if (pw_init(NULL, NULL)) 400 openpam_log(PAM_LOG_ERROR, "pw_init() failed"); 401 else if ((pfd = pw_lock()) == -1) 402 openpam_log(PAM_LOG_ERROR, "pw_lock() failed"); 403 else if ((tfd = pw_tmp(-1)) == -1) 404 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed"); 405 else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1) 406 openpam_log(PAM_LOG_ERROR, "pw_copy() failed"); 407 else if (pw_mkdb(pwd->pw_name) == -1) 408 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed"); 409 else 410 retval = PAM_SUCCESS; 411 pw_fini(); 412#ifdef YP 413 break; 414 case _PWF_NIS: 415 yp_domain = yp_server = NULL; 416 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 417 (void)pam_get_data(pamh, "yp_server", &yp_server); 418 ypclnt = ypclnt_new(yp_domain, 419 "passwd.byname", yp_server); 420 if (ypclnt == NULL) { 421 retval = PAM_BUF_ERR; 422 } else if (ypclnt_connect(ypclnt) == -1 || 423 ypclnt_passwd(ypclnt, pwd, old_pass) == -1) { 424 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error); 425 retval = PAM_SERVICE_ERR; 426 } else { 427 retval = PAM_SUCCESS; 428 } 429 ypclnt_free(ypclnt); 430 break; 431 default: 432 openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x", 433 pwd->pw_fields & _PWF_SOURCE); 434 retval = PAM_SERVICE_ERR; 435 } 436#endif 437 free(old_pwd); 438 } 439 else { 440 /* Very bad juju */ 441 retval = PAM_ABORT; 442 PAM_LOG("Illegal 'flags'"); 443 } 444 445 return (retval); 446} 447 448/* Mostly stolen from passwd(1)'s local_passwd.c - markm */ 449 450static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */ 451 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 452 453static void 454to64(char *s, long v, int n) 455{ 456 while (--n >= 0) { 457 *s++ = itoa64[v&0x3f]; 458 v >>= 6; 459 } 460} 461 462/* Salt suitable for traditional DES and MD5 */ 463static void 464makesalt(char salt[SALTSIZE + 1]) 465{ 466 int i; 467 468 /* These are not really random numbers, they are just 469 * numbers that change to thwart construction of a 470 * dictionary. 471 */ 472 for (i = 0; i < SALTSIZE; i += 4) 473 to64(&salt[i], arc4random(), 4); 474 salt[SALTSIZE] = '\0'; 475} 476 477PAM_MODULE_ENTRY("pam_unix"); 478