lib/pam_module/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  * $FreeBSD: src/lib/libpam/modules/pam_unix/pam_unix.c,v 1.53 2007/12/21 12:00:16 des Exp $
  37  * $DragonFly: src/lib/pam_module/pam_unix/pam_unix.c,v 1.1 2005/08/01 16:15:19 joerg Exp $
  38  */
  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 <unistd.h>
  54
  55 #include <libutil.h>
  56
  57 #ifdef YP
  58 #include <ypclnt.h>
  59 #endif
  60
  61 #define PAM_SM_AUTH
  62 #define PAM_SM_ACCOUNT
  63 #define PAM_SM_PASSWORD
  64
  65 #include <security/pam_appl.h>
  66 #include <security/pam_modules.h>
  67 #include <security/pam_mod_misc.h>
  68
  69 #define PASSWORD_HASH           "md5"
  70 #define DEFAULT_WARN            (2L * 7L * 86400L)  /* Two weeks */
  71 #define SALTSIZE                32
  72
  73 #define LOCKED_PREFIX           "*LOCKED*"
  74 #define LOCKED_PREFIX_LEN       (sizeof(LOCKED_PREFIX) - 1)
  75
  76 static void makesalt(char []);
  77
  78 static char password_hash[] =           PASSWORD_HASH;
  79
  80 #define PAM_OPT_LOCAL_PASS      "local_pass"
  81 #define PAM_OPT_NIS_PASS        "nis_pass"
  82
  83 char *tempname = NULL;
  84
  85 /*
  86  * authentication management
  87  */
  88 PAM_EXTERN int
  89 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  90     int argc __unused, const char *argv[] __unused)
  91 {
  92         login_cap_t *lc;
  93         struct passwd *pwd;
  94         int retval;
  95         const char *pass, *user, *realpw, *prompt;
  96
  97         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
  98                 pwd = getpwnam(getlogin());
  99         } else {
 100                 retval = pam_get_user(pamh, &user, NULL);
 101                 if (retval != PAM_SUCCESS)
 102                         return (retval);
 103                 pwd = getpwnam(user);
 104         }
 105
 106         PAM_LOG("Got user: %s", user);
 107
 108         if (pwd != NULL) {
 109                 PAM_LOG("Doing real authentication");
 110                 realpw = pwd->pw_passwd;
 111                 if (realpw[0] == '\0') {
 112                         if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) &&
 113                             openpam_get_option(pamh, PAM_OPT_NULLOK))
 114                                 return (PAM_SUCCESS);
 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 (strcmp(crypt(pass, realpw), realpw) == 0)
 130                 return (PAM_SUCCESS);
 131
 132         PAM_VERBOSE_ERROR("UNIX authentication refused");
 133         return (PAM_AUTH_ERR);
 134 }
 135
 136 PAM_EXTERN int
 137 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 138     int argc __unused, const char *argv[] __unused)
 139 {
 140
 141         return (PAM_SUCCESS);
 142 }
 143
 144 /*
 145  * account management
 146  */
 147 PAM_EXTERN int
 148 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
 149     int argc __unused, const char *argv[] __unused)
 150 {
 151         struct addrinfo hints, *res;
 152         struct passwd *pwd;
 153         struct timeval tp;
 154         login_cap_t *lc;
 155         time_t warntime;
 156         int retval;
 157         const char *user;
 158         const void *rhost, *tty;
 159         char rhostip[MAXHOSTNAMELEN] = "";
 160
 161         retval = pam_get_user(pamh, &user, NULL);
 162         if (retval != PAM_SUCCESS)
 163                 return (retval);
 164
 165         if (user == NULL || (pwd = getpwnam(user)) == NULL)
 166                 return (PAM_SERVICE_ERR);
 167
 168         PAM_LOG("Got user: %s", user);
 169
 170         retval = pam_get_item(pamh, PAM_RHOST, &rhost);
 171         if (retval != PAM_SUCCESS)
 172                 return (retval);
 173
 174         retval = pam_get_item(pamh, PAM_TTY, &tty);
 175         if (retval != PAM_SUCCESS)
 176                 return (retval);
 177
 178         if (*pwd->pw_passwd == '\0' &&
 179             (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0)
 180                 return (PAM_NEW_AUTHTOK_REQD);
 181
 182         if (strncmp(pwd->pw_passwd, LOCKED_PREFIX, LOCKED_PREFIX_LEN) == 0)
 183                 return (PAM_AUTH_ERR);
 184
 185         lc = login_getpwclass(pwd);
 186         if (lc == NULL) {
 187                 PAM_LOG("Unable to get login class for user %s", user);
 188                 return (PAM_SERVICE_ERR);
 189         }
 190
 191         PAM_LOG("Got login_cap");
 192
 193         if (pwd->pw_change || pwd->pw_expire)
 194                 gettimeofday(&tp, NULL);
 195
 196         /*
 197          * Check pw_expire before pw_change - no point in letting the
 198          * user change the password on an expired account.
 199          */
 200
 201         if (pwd->pw_expire) {
 202                 warntime = login_getcaptime(lc, "warnexpire",
 203                     DEFAULT_WARN, DEFAULT_WARN);
 204                 if (tp.tv_sec >= pwd->pw_expire) {
 205                         login_close(lc);
 206                         return (PAM_ACCT_EXPIRED);
 207                 } else if (pwd->pw_expire - tp.tv_sec < warntime &&
 208                     (flags & PAM_SILENT) == 0) {
 209                         pam_error(pamh, "Warning: your account expires on %s",
 210                             ctime(&pwd->pw_expire));
 211                 }
 212         }
 213
 214         retval = PAM_SUCCESS;
 215         if (pwd->pw_change) {
 216                 warntime = login_getcaptime(lc, "warnpassword",
 217                     DEFAULT_WARN, DEFAULT_WARN);
 218                 if (tp.tv_sec >= pwd->pw_change) {
 219                         retval = PAM_NEW_AUTHTOK_REQD;
 220                 } else if (pwd->pw_change - tp.tv_sec < warntime &&
 221                     (flags & PAM_SILENT) == 0) {
 222                         pam_error(pamh, "Warning: your password expires on %s",
 223                             ctime(&pwd->pw_change));
 224                 }
 225         }
 226
 227         /*
 228          * From here on, we must leave retval untouched (unless we
 229          * know we're going to fail), because we need to remember
 230          * whether we're supposed to return PAM_SUCCESS or
 231          * PAM_NEW_AUTHTOK_REQD.
 232          */
 233
 234         if (rhost && *(const char *)rhost != '\0') {
 235                 memset(&hints, 0, sizeof(hints));
 236                 hints.ai_family = AF_UNSPEC;
 237                 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) {
 238                         getnameinfo(res->ai_addr, res->ai_addrlen,
 239                             rhostip, sizeof(rhostip), NULL, 0,
 240                             NI_NUMERICHOST);
 241                 }
 242                 if (res != NULL)
 243                         freeaddrinfo(res);
 244         }
 245
 246         /*
 247          * Check host / tty / time-of-day restrictions
 248          */
 249
 250         if (!auth_hostok(lc, rhost, rhostip) ||
 251             !auth_ttyok(lc, tty) ||
 252             !auth_timeok(lc, time(NULL)))
 253                 retval = PAM_AUTH_ERR;
 254
 255         login_close(lc);
 256
 257         return (retval);
 258 }
 259
 260 /*
 261  * password management
 262  *
 263  * standard Unix and NIS password changing
 264  */
 265 PAM_EXTERN int
 266 pam_sm_chauthtok(pam_handle_t *pamh, int flags,
 267     int argc __unused, const char *argv[] __unused)
 268 {
 269 #ifdef YP
 270         struct ypclnt *ypclnt;
 271         const void *yp_domain, *yp_server;
 272 #endif
 273         char salt[SALTSIZE + 1];
 274         login_cap_t * lc;
 275         struct passwd *pwd, *old_pwd;
 276         const char *user, *old_pass, *new_pass;
 277         char *encrypted;
 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                         pam_get_data(pamh, "yp_domain", &yp_domain);
 308                         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                 pwd->pw_change = 0;
 381                 lc = login_getclass(pwd->pw_class);
 382                 if (login_setcryptfmt(lc, password_hash, NULL) == NULL)
 383                         openpam_log(PAM_LOG_ERROR,
 384                             "can't set password cipher, relying on default");
 385                 login_close(lc);
 386                 makesalt(salt);
 387                 pwd->pw_passwd = crypt(new_pass, salt);
 388 #ifdef YP
 389                 switch (old_pwd->pw_fields & _PWF_SOURCE) {
 390                 case _PWF_FILES:
 391 #endif
 392                         retval = PAM_SERVICE_ERR;
 393                         if (pw_init(NULL, NULL))
 394                                 openpam_log(PAM_LOG_ERROR, "pw_init() failed");
 395                         else if ((pfd = pw_lock()) == -1)
 396                                 openpam_log(PAM_LOG_ERROR, "pw_lock() failed");
 397                         else if ((tfd = pw_tmp(-1)) == -1)
 398                                 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed");
 399                         else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1)
 400                                 openpam_log(PAM_LOG_ERROR, "pw_copy() failed");
 401                         else if (pw_mkdb(pwd->pw_name) == -1)
 402                                 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed");
 403                         else
 404                                 retval = PAM_SUCCESS;
 405                         pw_fini();
 406 #ifdef YP
 407                         break;
 408                 case _PWF_NIS:
 409                         yp_domain = yp_server = NULL;
 410                         pam_get_data(pamh, "yp_domain", &yp_domain);
 411                         pam_get_data(pamh, "yp_server", &yp_server);
 412                         ypclnt = ypclnt_new(yp_domain,
 413                             "passwd.byname", yp_server);
 414                         if (ypclnt == NULL) {
 415                                 retval = PAM_BUF_ERR;
 416                         } else if (ypclnt_connect(ypclnt) == -1 ||
 417                             ypclnt_passwd(ypclnt, pwd, old_pass) == -1) {
 418                                 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error);
 419                                 retval = PAM_SERVICE_ERR;
 420                         } else {
 421                                 retval = PAM_SUCCESS;
 422                         }
 423                         ypclnt_free(ypclnt);
 424                         break;
 425                 default:
 426                         openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x",
 427                             pwd->pw_fields & _PWF_SOURCE);
 428                         retval = PAM_SERVICE_ERR;
 429                 }
 430 #endif
 431                 free(old_pwd);
 432         }
 433         else {
 434                 /* Very bad juju */
 435                 retval = PAM_ABORT;
 436                 PAM_LOG("Illegal 'flags'");
 437         }
 438
 439         return (retval);
 440 }
 441
 442 /* Mostly stolen from passwd(1)'s local_passwd.c - markm */
 443
 444 static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
 445         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 446
 447 static void
 448 to64(char *s, long v, int n)
 449 {
 450         while (--n >= 0) {
 451                 *s++ = itoa64[v&0x3f];
 452                 v >>= 6;
 453         }
 454 }
 455
 456 /* Salt suitable for traditional DES and MD5 */
 457 void
 458 makesalt(char salt[SALTSIZE])
 459 {
 460         int i;
 461
 462         /* These are not really random numbers, they are just
 463          * numbers that change to thwart construction of a
 464          * dictionary. This is exposed to the public.
 465          */
 466         for (i = 0; i < SALTSIZE; i += 4)
 467                 to64(&salt[i], arc4random(), 4);
 468         salt[SALTSIZE] = '\0';
 469 }
 470
 471 PAM_MODULE_ENTRY("pam_unix");