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 char *tempname = NULL;
  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
  98         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
  99                 pwd = getpwnam(getlogin());
 100         } else {
 101                 retval = pam_get_user(pamh, &user, NULL);
 102                 if (retval != PAM_SUCCESS)
 103                         return (retval);
 104                 pwd = getpwnam(user);
 105         }
 106
 107         PAM_LOG("Got user: %s", user);
 108
 109         if (pwd != NULL) {
 110                 PAM_LOG("Doing real authentication");
 111                 realpw = pwd->pw_passwd;
 112                 if (realpw[0] == '\0') {
 113                         if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) &&
 114                             openpam_get_option(pamh, PAM_OPT_NULLOK))
 115                                 return (PAM_SUCCESS);
 116                         realpw = "*";
 117                 }
 118                 lc = login_getpwclass(pwd);
 119         } else {
 120                 PAM_LOG("Doing dummy authentication");
 121                 realpw = "*";
 122                 lc = login_getclass(NULL);
 123         }
 124         prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL);
 125         retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt);
 126         login_close(lc);
 127         if (retval != PAM_SUCCESS)
 128                 return (retval);
 129         PAM_LOG("Got password");
 130         if (strcmp(crypt(pass, realpw), realpw) == 0)
 131                 return (PAM_SUCCESS);
 132
 133         PAM_VERBOSE_ERROR("UNIX authentication refused");
 134         return (PAM_AUTH_ERR);
 135 }
 136
 137 PAM_EXTERN int
 138 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 139     int argc __unused, const char *argv[] __unused)
 140 {
 141
 142         return (PAM_SUCCESS);
 143 }
 144
 145 /*
 146  * account management
 147  */
 148 PAM_EXTERN int
 149 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
 150     int argc __unused, const char *argv[] __unused)
 151 {
 152         struct addrinfo hints, *res;
 153         struct passwd *pwd;
 154         struct timeval tp;
 155         login_cap_t *lc;
 156         time_t warntime;
 157         int retval;
 158         const char *user;
 159         const void *rhost, *tty;
 160         char rhostip[MAXHOSTNAMELEN] = "";
 161
 162         retval = pam_get_user(pamh, &user, NULL);
 163         if (retval != PAM_SUCCESS)
 164                 return (retval);
 165
 166         if (user == NULL || (pwd = getpwnam(user)) == NULL)
 167                 return (PAM_SERVICE_ERR);
 168
 169         PAM_LOG("Got user: %s", user);
 170
 171         retval = pam_get_item(pamh, PAM_RHOST, &rhost);
 172         if (retval != PAM_SUCCESS)
 173                 return (retval);
 174
 175         retval = pam_get_item(pamh, PAM_TTY, &tty);
 176         if (retval != PAM_SUCCESS)
 177                 return (retval);
 178
 179         if (*pwd->pw_passwd == '\0' &&
 180             (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0)
 181                 return (PAM_NEW_AUTHTOK_REQD);
 182
 183         if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0)
 184                 return (PAM_AUTH_ERR);
 185
 186         lc = login_getpwclass(pwd);
 187         if (lc == NULL) {
 188                 PAM_LOG("Unable to get login class for user %s", user);
 189                 return (PAM_SERVICE_ERR);
 190         }
 191
 192         PAM_LOG("Got login_cap");
 193
 194         if (pwd->pw_change || pwd->pw_expire)
 195                 gettimeofday(&tp, NULL);
 196
 197         /*
 198          * Check pw_expire before pw_change - no point in letting the
 199          * user change the password on an expired account.
 200          */
 201
 202         if (pwd->pw_expire) {
 203                 warntime = login_getcaptime(lc, "warnexpire",
 204                     DEFAULT_WARN, DEFAULT_WARN);
 205                 if (tp.tv_sec >= pwd->pw_expire) {
 206                         login_close(lc);
 207                         return (PAM_ACCT_EXPIRED);
 208                 } else if (pwd->pw_expire - tp.tv_sec < warntime &&
 209                     (flags & PAM_SILENT) == 0) {
 210                         pam_error(pamh, "Warning: your account expires on %s",
 211                             ctime(&pwd->pw_expire));
 212                 }
 213         }
 214
 215         retval = PAM_SUCCESS;
 216         if (pwd->pw_change) {
 217                 warntime = login_getcaptime(lc, "warnpassword",
 218                     DEFAULT_WARN, DEFAULT_WARN);
 219                 if (tp.tv_sec >= pwd->pw_change) {
 220                         retval = PAM_NEW_AUTHTOK_REQD;
 221                 } else if (pwd->pw_change - tp.tv_sec < warntime &&
 222                     (flags & PAM_SILENT) == 0) {
 223                         pam_error(pamh, "Warning: your password expires on %s",
 224                             ctime(&pwd->pw_change));
 225                 }
 226         }
 227
 228         /*
 229          * From here on, we must leave retval untouched (unless we
 230          * know we're going to fail), because we need to remember
 231          * whether we're supposed to return PAM_SUCCESS or
 232          * PAM_NEW_AUTHTOK_REQD.
 233          */
 234
 235         if (rhost && *(const char *)rhost != '\0') {
 236                 memset(&hints, 0, sizeof(hints));
 237                 hints.ai_family = AF_UNSPEC;
 238                 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) {
 239                         getnameinfo(res->ai_addr, res->ai_addrlen,
 240                             rhostip, sizeof(rhostip), NULL, 0,
 241                             NI_NUMERICHOST);
 242                 }
 243                 if (res != NULL)
 244                         freeaddrinfo(res);
 245         }
 246
 247         /*
 248          * Check host / tty / time-of-day restrictions
 249          */
 250
 251         if (!auth_hostok(lc, rhost, rhostip) ||
 252             !auth_ttyok(lc, tty) ||
 253             !auth_timeok(lc, time(NULL)))
 254                 retval = PAM_AUTH_ERR;
 255
 256         login_close(lc);
 257
 258         return (retval);
 259 }
 260
 261 /*
 262  * password management
 263  *
 264  * standard Unix and NIS password changing
 265  */
 266 PAM_EXTERN int
 267 pam_sm_chauthtok(pam_handle_t *pamh, int flags,
 268     int argc __unused, const char *argv[] __unused)
 269 {
 270 #ifdef YP
 271         struct ypclnt *ypclnt;
 272         const void *yp_domain, *yp_server;
 273 #endif
 274         char salt[SALTSIZE + 1];
 275         login_cap_t *lc;
 276         struct passwd *pwd, *old_pwd;
 277         const char *user, *old_pass, *new_pass;
 278         char *encrypted;
 279         time_t passwordtime;
 280         int pfd, tfd, retval;
 281
 282         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF))
 283                 pwd = getpwnam(getlogin());
 284         else {
 285                 retval = pam_get_user(pamh, &user, NULL);
 286                 if (retval != PAM_SUCCESS)
 287                         return (retval);
 288                 pwd = getpwnam(user);
 289         }
 290
 291         if (pwd == NULL)
 292                 return (PAM_AUTHTOK_RECOVERY_ERR);
 293
 294         PAM_LOG("Got user: %s", user);
 295
 296         if (flags & PAM_PRELIM_CHECK) {
 297
 298                 PAM_LOG("PRELIM round");
 299
 300                 if (getuid() == 0 &&
 301                     (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES)
 302                         /* root doesn't need the old password */
 303                         return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
 304 #ifdef YP
 305                 if (getuid() == 0 &&
 306                     (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS) {
 307
 308                         yp_domain = yp_server = NULL;
 309                         (void)pam_get_data(pamh, "yp_domain", &yp_domain);
 310                         (void)pam_get_data(pamh, "yp_server", &yp_server);
 311
 312                         ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server);
 313                         if (ypclnt == NULL)
 314                                 return (PAM_BUF_ERR);
 315
 316                         if (ypclnt_connect(ypclnt) == -1) {
 317                                 ypclnt_free(ypclnt);
 318                                 return (PAM_SERVICE_ERR);
 319                         }
 320
 321                         retval = ypclnt_havepasswdd(ypclnt);
 322                         ypclnt_free(ypclnt);
 323                         if (retval == 1)
 324                                 return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
 325                         else if (retval == -1)
 326                                 return (PAM_SERVICE_ERR);
 327                 }
 328 #endif
 329                 if (pwd->pw_passwd[0] == '\0'
 330                     && openpam_get_option(pamh, PAM_OPT_NULLOK)) {
 331                         /*
 332                          * No password case. XXX Are we giving too much away
 333                          * by not prompting for a password?
 334                          * XXX check PAM_DISALLOW_NULL_AUTHTOK
 335                          */
 336                         old_pass = "";
 337                 } else {
 338                         retval = pam_get_authtok(pamh,
 339                             PAM_OLDAUTHTOK, &old_pass, NULL);
 340                         if (retval != PAM_SUCCESS)
 341                                 return (retval);
 342                 }
 343                 PAM_LOG("Got old password");
 344                 /* always encrypt first */
 345                 encrypted = crypt(old_pass, pwd->pw_passwd);
 346                 if (old_pass[0] == '\0' &&
 347                     !openpam_get_option(pamh, PAM_OPT_NULLOK))
 348                         return (PAM_PERM_DENIED);
 349                 if (strcmp(encrypted, pwd->pw_passwd) != 0)
 350                         return (PAM_PERM_DENIED);
 351         }
 352         else if (flags & PAM_UPDATE_AUTHTOK) {
 353                 PAM_LOG("UPDATE round");
 354
 355                 retval = pam_get_authtok(pamh,
 356                     PAM_OLDAUTHTOK, &old_pass, NULL);
 357                 if (retval != PAM_SUCCESS)
 358                         return (retval);
 359                 PAM_LOG("Got old password");
 360
 361                 /* get new password */
 362                 for (;;) {
 363                         retval = pam_get_authtok(pamh,
 364                             PAM_AUTHTOK, &new_pass, NULL);
 365                         if (retval != PAM_TRY_AGAIN)
 366                                 break;
 367                         pam_error(pamh, "Mismatch; try again, EOF to quit.");
 368                 }
 369                 PAM_LOG("Got new password");
 370                 if (retval != PAM_SUCCESS) {
 371                         PAM_VERBOSE_ERROR("Unable to get new password");
 372                         return (retval);
 373                 }
 374
 375                 if (getuid() != 0 && new_pass[0] == '\0' &&
 376                     !openpam_get_option(pamh, PAM_OPT_NULLOK))
 377                         return (PAM_PERM_DENIED);
 378
 379                 if ((old_pwd = pw_dup(pwd)) == NULL)
 380                         return (PAM_BUF_ERR);
 381
 382                 lc = login_getclass(pwd->pw_class);
 383                 if (login_setcryptfmt(lc, password_hash, NULL) == NULL)
 384                         openpam_log(PAM_LOG_ERROR,
 385                             "can't set password cipher, relying on default");
 386
 387                 /* set password expiry date */
 388                 pwd->pw_change = 0;
 389                 passwordtime = login_getcaptime(lc, "passwordtime", 0, 0);
 390                 if (passwordtime > 0)
 391                         pwd->pw_change = time(NULL) + passwordtime;
 392
 393                 login_close(lc);
 394                 makesalt(salt);
 395                 pwd->pw_passwd = crypt(new_pass, salt);
 396 #ifdef YP
 397                 switch (old_pwd->pw_fields & _PWF_SOURCE) {
 398                 case _PWF_FILES:
 399 #endif
 400                         retval = PAM_SERVICE_ERR;
 401                         if (pw_init(NULL, NULL))
 402                                 openpam_log(PAM_LOG_ERROR, "pw_init() failed");
 403                         else if ((pfd = pw_lock()) == -1)
 404                                 openpam_log(PAM_LOG_ERROR, "pw_lock() failed");
 405                         else if ((tfd = pw_tmp(-1)) == -1)
 406                                 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed");
 407                         else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1)
 408                                 openpam_log(PAM_LOG_ERROR, "pw_copy() failed");
 409                         else if (pw_mkdb(pwd->pw_name) == -1)
 410                                 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed");
 411                         else
 412                                 retval = PAM_SUCCESS;
 413                         pw_fini();
 414 #ifdef YP
 415                         break;
 416                 case _PWF_NIS:
 417                         yp_domain = yp_server = NULL;
 418                         (void)pam_get_data(pamh, "yp_domain", &yp_domain);
 419                         (void)pam_get_data(pamh, "yp_server", &yp_server);
 420                         ypclnt = ypclnt_new(yp_domain,
 421                             "passwd.byname", yp_server);
 422                         if (ypclnt == NULL) {
 423                                 retval = PAM_BUF_ERR;
 424                         } else if (ypclnt_connect(ypclnt) == -1 ||
 425                             ypclnt_passwd(ypclnt, pwd, old_pass) == -1) {
 426                                 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error);
 427                                 retval = PAM_SERVICE_ERR;
 428                         } else {
 429                                 retval = PAM_SUCCESS;
 430                         }
 431                         ypclnt_free(ypclnt);
 432                         break;
 433                 default:
 434                         openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x",
 435                             pwd->pw_fields & _PWF_SOURCE);
 436                         retval = PAM_SERVICE_ERR;
 437                 }
 438 #endif
 439                 free(old_pwd);
 440         }
 441         else {
 442                 /* Very bad juju */
 443                 retval = PAM_ABORT;
 444                 PAM_LOG("Illegal 'flags'");
 445         }
 446
 447         return (retval);
 448 }
 449
 450 /* Mostly stolen from passwd(1)'s local_passwd.c - markm */
 451
 452 static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
 453         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 454
 455 static void
 456 to64(char *s, long v, int n)
 457 {
 458         while (--n >= 0) {
 459                 *s++ = itoa64[v&0x3f];
 460                 v >>= 6;
 461         }
 462 }
 463
 464 /* Salt suitable for traditional DES and MD5 */
 465 void
 466 makesalt(char salt[SALTSIZE])
 467 {
 468         int i;
 469
 470         /* These are not really random numbers, they are just
 471          * numbers that change to thwart construction of a
 472          * dictionary. This is exposed to the public.
 473          */
 474         for (i = 0; i < SALTSIZE; i += 4)
 475                 to64(&salt[i], arc4random(), 4);
 476         salt[SALTSIZE] = '\0';
 477 }
 478
 479 PAM_MODULE_ENTRY("pam_unix");