pam_unix.c revision 331722
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/11/lib/libpam/modules/pam_unix/pam_unix.c 331722 2018-03-29 02:50:57Z eadler $"); 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 PAM_LOG("Password is empty, using fake password"); 115 realpw = "*"; 116 } 117 lc = login_getpwclass(pwd); 118 } else { 119 PAM_LOG("Doing dummy authentication"); 120 realpw = "*"; 121 lc = login_getclass(NULL); 122 } 123 prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL); 124 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt); 125 login_close(lc); 126 if (retval != PAM_SUCCESS) 127 return (retval); 128 PAM_LOG("Got password"); 129 if (strnlen(pass, _PASSWORD_LEN + 1) > _PASSWORD_LEN) { 130 PAM_LOG("Password is too long, using fake password"); 131 realpw = "*"; 132 } 133 if (strcmp(crypt(pass, realpw), realpw) == 0) 134 return (PAM_SUCCESS); 135 136 PAM_VERBOSE_ERROR("UNIX authentication refused"); 137 return (PAM_AUTH_ERR); 138} 139 140PAM_EXTERN int 141pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused, 142 int argc __unused, const char *argv[] __unused) 143{ 144 145 return (PAM_SUCCESS); 146} 147 148/* 149 * account management 150 */ 151PAM_EXTERN int 152pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 153 int argc __unused, const char *argv[] __unused) 154{ 155 struct addrinfo hints, *res; 156 struct passwd *pwd; 157 struct timeval tp; 158 login_cap_t *lc; 159 time_t warntime; 160 int retval; 161 const char *user; 162 const void *rhost, *tty; 163 char rhostip[MAXHOSTNAMELEN] = ""; 164 165 retval = pam_get_user(pamh, &user, NULL); 166 if (retval != PAM_SUCCESS) 167 return (retval); 168 169 if (user == NULL || (pwd = getpwnam(user)) == NULL) 170 return (PAM_SERVICE_ERR); 171 172 PAM_LOG("Got user: %s", user); 173 174 retval = pam_get_item(pamh, PAM_RHOST, &rhost); 175 if (retval != PAM_SUCCESS) 176 return (retval); 177 178 retval = pam_get_item(pamh, PAM_TTY, &tty); 179 if (retval != PAM_SUCCESS) 180 return (retval); 181 182 if (*pwd->pw_passwd == '\0' && 183 (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0) 184 return (PAM_NEW_AUTHTOK_REQD); 185 186 if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0) 187 return (PAM_AUTH_ERR); 188 189 lc = login_getpwclass(pwd); 190 if (lc == NULL) { 191 PAM_LOG("Unable to get login class for user %s", user); 192 return (PAM_SERVICE_ERR); 193 } 194 195 PAM_LOG("Got login_cap"); 196 197 if (pwd->pw_change || pwd->pw_expire) 198 gettimeofday(&tp, NULL); 199 200 /* 201 * Check pw_expire before pw_change - no point in letting the 202 * user change the password on an expired account. 203 */ 204 205 if (pwd->pw_expire) { 206 warntime = login_getcaptime(lc, "warnexpire", 207 DEFAULT_WARN, DEFAULT_WARN); 208 if (tp.tv_sec >= pwd->pw_expire) { 209 login_close(lc); 210 return (PAM_ACCT_EXPIRED); 211 } else if (pwd->pw_expire - tp.tv_sec < warntime && 212 (flags & PAM_SILENT) == 0) { 213 pam_error(pamh, "Warning: your account expires on %s", 214 ctime(&pwd->pw_expire)); 215 } 216 } 217 218 retval = PAM_SUCCESS; 219 if (pwd->pw_change) { 220 warntime = login_getcaptime(lc, "warnpassword", 221 DEFAULT_WARN, DEFAULT_WARN); 222 if (tp.tv_sec >= pwd->pw_change) { 223 retval = PAM_NEW_AUTHTOK_REQD; 224 } else if (pwd->pw_change - tp.tv_sec < warntime && 225 (flags & PAM_SILENT) == 0) { 226 pam_error(pamh, "Warning: your password expires on %s", 227 ctime(&pwd->pw_change)); 228 } 229 } 230 231 /* 232 * From here on, we must leave retval untouched (unless we 233 * know we're going to fail), because we need to remember 234 * whether we're supposed to return PAM_SUCCESS or 235 * PAM_NEW_AUTHTOK_REQD. 236 */ 237 238 if (rhost && *(const char *)rhost != '\0') { 239 memset(&hints, 0, sizeof(hints)); 240 hints.ai_family = AF_UNSPEC; 241 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) { 242 getnameinfo(res->ai_addr, res->ai_addrlen, 243 rhostip, sizeof(rhostip), NULL, 0, 244 NI_NUMERICHOST); 245 } 246 if (res != NULL) 247 freeaddrinfo(res); 248 } 249 250 /* 251 * Check host / tty / time-of-day restrictions 252 */ 253 254 if (!auth_hostok(lc, rhost, rhostip) || 255 !auth_ttyok(lc, tty) || 256 !auth_timeok(lc, time(NULL))) 257 retval = PAM_AUTH_ERR; 258 259 login_close(lc); 260 261 return (retval); 262} 263 264/* 265 * password management 266 * 267 * standard Unix and NIS password changing 268 */ 269PAM_EXTERN int 270pam_sm_chauthtok(pam_handle_t *pamh, int flags, 271 int argc __unused, const char *argv[] __unused) 272{ 273#ifdef YP 274 struct ypclnt *ypclnt; 275 const void *yp_domain, *yp_server; 276#endif 277 char salt[SALTSIZE + 1]; 278 login_cap_t *lc; 279 struct passwd *pwd, *old_pwd; 280 const char *user, *old_pass, *new_pass; 281 char *encrypted; 282 time_t passwordtime; 283 int pfd, tfd, retval; 284 285 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 286 user = getlogin(); 287 else { 288 retval = pam_get_user(pamh, &user, NULL); 289 if (retval != PAM_SUCCESS) 290 return (retval); 291 } 292 pwd = getpwnam(user); 293 294 if (pwd == NULL) 295 return (PAM_AUTHTOK_RECOVERY_ERR); 296 297 PAM_LOG("Got user: %s", user); 298 299 if (flags & PAM_PRELIM_CHECK) { 300 301 PAM_LOG("PRELIM round"); 302 303 if (getuid() == 0 && 304 (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES) 305 /* root doesn't need the old password */ 306 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 307#ifdef YP 308 if (getuid() == 0 && 309 (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS) { 310 311 yp_domain = yp_server = NULL; 312 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 313 (void)pam_get_data(pamh, "yp_server", &yp_server); 314 315 ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server); 316 if (ypclnt == NULL) 317 return (PAM_BUF_ERR); 318 319 if (ypclnt_connect(ypclnt) == -1) { 320 ypclnt_free(ypclnt); 321 return (PAM_SERVICE_ERR); 322 } 323 324 retval = ypclnt_havepasswdd(ypclnt); 325 ypclnt_free(ypclnt); 326 if (retval == 1) 327 return (pam_set_item(pamh, PAM_OLDAUTHTOK, "")); 328 else if (retval == -1) 329 return (PAM_SERVICE_ERR); 330 } 331#endif 332 if (pwd->pw_passwd[0] == '\0' 333 && openpam_get_option(pamh, PAM_OPT_NULLOK)) { 334 /* 335 * No password case. XXX Are we giving too much away 336 * by not prompting for a password? 337 * XXX check PAM_DISALLOW_NULL_AUTHTOK 338 */ 339 old_pass = ""; 340 retval = PAM_SUCCESS; 341 } else { 342 retval = pam_get_authtok(pamh, 343 PAM_OLDAUTHTOK, &old_pass, NULL); 344 if (retval != PAM_SUCCESS) 345 return (retval); 346 } 347 PAM_LOG("Got old password"); 348 /* always encrypt first */ 349 encrypted = crypt(old_pass, pwd->pw_passwd); 350 if (old_pass[0] == '\0' && 351 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 352 return (PAM_PERM_DENIED); 353 if (strcmp(encrypted, pwd->pw_passwd) != 0) 354 return (PAM_PERM_DENIED); 355 } 356 else if (flags & PAM_UPDATE_AUTHTOK) { 357 PAM_LOG("UPDATE round"); 358 359 retval = pam_get_authtok(pamh, 360 PAM_OLDAUTHTOK, &old_pass, NULL); 361 if (retval != PAM_SUCCESS) 362 return (retval); 363 PAM_LOG("Got old password"); 364 365 /* get new password */ 366 for (;;) { 367 retval = pam_get_authtok(pamh, 368 PAM_AUTHTOK, &new_pass, NULL); 369 if (retval != PAM_TRY_AGAIN) 370 break; 371 pam_error(pamh, "Mismatch; try again, EOF to quit."); 372 } 373 PAM_LOG("Got new password"); 374 if (retval != PAM_SUCCESS) { 375 PAM_VERBOSE_ERROR("Unable to get new password"); 376 return (retval); 377 } 378 379 if (getuid() != 0 && new_pass[0] == '\0' && 380 !openpam_get_option(pamh, PAM_OPT_NULLOK)) 381 return (PAM_PERM_DENIED); 382 383 if ((old_pwd = pw_dup(pwd)) == NULL) 384 return (PAM_BUF_ERR); 385 386 lc = login_getclass(pwd->pw_class); 387 if (login_setcryptfmt(lc, password_hash, NULL) == NULL) 388 openpam_log(PAM_LOG_ERROR, 389 "can't set password cipher, relying on default"); 390 391 /* set password expiry date */ 392 pwd->pw_change = 0; 393 passwordtime = login_getcaptime(lc, "passwordtime", 0, 0); 394 if (passwordtime > 0) 395 pwd->pw_change = time(NULL) + passwordtime; 396 397 login_close(lc); 398 makesalt(salt); 399 pwd->pw_passwd = crypt(new_pass, salt); 400#ifdef YP 401 switch (old_pwd->pw_fields & _PWF_SOURCE) { 402 case _PWF_FILES: 403#endif 404 retval = PAM_SERVICE_ERR; 405 if (pw_init(NULL, NULL)) 406 openpam_log(PAM_LOG_ERROR, "pw_init() failed"); 407 else if ((pfd = pw_lock()) == -1) 408 openpam_log(PAM_LOG_ERROR, "pw_lock() failed"); 409 else if ((tfd = pw_tmp(-1)) == -1) 410 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed"); 411 else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1) 412 openpam_log(PAM_LOG_ERROR, "pw_copy() failed"); 413 else if (pw_mkdb(pwd->pw_name) == -1) 414 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed"); 415 else 416 retval = PAM_SUCCESS; 417 pw_fini(); 418#ifdef YP 419 break; 420 case _PWF_NIS: 421 yp_domain = yp_server = NULL; 422 (void)pam_get_data(pamh, "yp_domain", &yp_domain); 423 (void)pam_get_data(pamh, "yp_server", &yp_server); 424 ypclnt = ypclnt_new(yp_domain, 425 "passwd.byname", yp_server); 426 if (ypclnt == NULL) { 427 retval = PAM_BUF_ERR; 428 } else if (ypclnt_connect(ypclnt) == -1 || 429 ypclnt_passwd(ypclnt, pwd, old_pass) == -1) { 430 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error); 431 retval = PAM_SERVICE_ERR; 432 } else { 433 retval = PAM_SUCCESS; 434 } 435 ypclnt_free(ypclnt); 436 break; 437 default: 438 openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x", 439 pwd->pw_fields & _PWF_SOURCE); 440 retval = PAM_SERVICE_ERR; 441 } 442#endif 443 free(old_pwd); 444 } 445 else { 446 /* Very bad juju */ 447 retval = PAM_ABORT; 448 PAM_LOG("Illegal 'flags'"); 449 } 450 451 return (retval); 452} 453 454/* Mostly stolen from passwd(1)'s local_passwd.c - markm */ 455 456static unsigned char itoa64[] = /* 0 ... 63 => ascii - 64 */ 457 "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; 458 459static void 460to64(char *s, long v, int n) 461{ 462 while (--n >= 0) { 463 *s++ = itoa64[v&0x3f]; 464 v >>= 6; 465 } 466} 467 468/* Salt suitable for traditional DES and MD5 */ 469static void 470makesalt(char salt[SALTSIZE + 1]) 471{ 472 int i; 473 474 /* These are not really random numbers, they are just 475 * numbers that change to thwart construction of a 476 * dictionary. 477 */ 478 for (i = 0; i < SALTSIZE; i += 4) 479 to64(&salt[i], arc4random(), 4); 480 salt[SALTSIZE] = '\0'; 481} 482 483PAM_MODULE_ENTRY("pam_unix"); 484