lib/libpam/modules/pam_unix/pam_unix.c

   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("$FreeBSD$");
  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
  77 static void makesalt(char []);
  78
  79 static 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  */
  87 PAM_EXTERN int
  88 pam_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
 135 PAM_EXTERN int
 136 pam_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  */
 146 PAM_EXTERN int
 147 pam_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  */
 264 PAM_EXTERN int
 265 pam_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                 pwd = getpwnam(getlogin());
 282         else {
 283                 retval = pam_get_user(pamh, &user, NULL);
 284                 if (retval != PAM_SUCCESS)
 285                         return (retval);
 286                 pwd = getpwnam(user);
 287         }
 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
 450 static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
 451         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 452
 453 static void
 454 to64(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 */
 463 static void
 464 makesalt(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
 477 PAM_MODULE_ENTRY("pam_unix");