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 1.51 2005/07/05 18:42:18 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 static void makesalt(char []);
  74
  75 static char password_hash[] =           PASSWORD_HASH;
  76
  77 #define PAM_OPT_LOCAL_PASS      "local_pass"
  78 #define PAM_OPT_NIS_PASS        "nis_pass"
  79
  80 char *tempname = NULL;
  81
  82 /*
  83  * authentication management
  84  */
  85 PAM_EXTERN int
  86 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
  87     int argc __unused, const char *argv[] __unused)
  88 {
  89         login_cap_t *lc;
  90         struct passwd *pwd;
  91         int retval;
  92         const char *pass, *user, *realpw, *prompt;
  93
  94         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) {
  95                 pwd = getpwnam(getlogin());
  96         } else {
  97                 retval = pam_get_user(pamh, &user, NULL);
  98                 if (retval != PAM_SUCCESS)
  99                         return (retval);
 100                 pwd = getpwnam(user);
 101         }
 102
 103         PAM_LOG("Got user: %s", user);
 104
 105         if (pwd != NULL) {
 106                 PAM_LOG("Doing real authentication");
 107                 realpw = pwd->pw_passwd;
 108                 if (realpw[0] == '\0') {
 109                         if (!(flags & PAM_DISALLOW_NULL_AUTHTOK) &&
 110                             openpam_get_option(pamh, PAM_OPT_NULLOK))
 111                                 return (PAM_SUCCESS);
 112                         realpw = "*";
 113                 }
 114                 lc = login_getpwclass(pwd);
 115         } else {
 116                 PAM_LOG("Doing dummy authentication");
 117                 realpw = "*";
 118                 lc = login_getclass(NULL);
 119         }
 120         prompt = login_getcapstr(lc, "passwd_prompt", NULL, NULL);
 121         retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, prompt);
 122         login_close(lc);
 123         if (retval != PAM_SUCCESS)
 124                 return (retval);
 125         PAM_LOG("Got password");
 126         if (strcmp(crypt(pass, realpw), realpw) == 0)
 127                 return (PAM_SUCCESS);
 128
 129         return (PAM_AUTH_ERR);
 130 }
 131
 132 PAM_EXTERN int
 133 pam_sm_setcred(pam_handle_t *pamh __unused, int flags __unused,
 134     int argc __unused, const char *argv[] __unused)
 135 {
 136
 137         return (PAM_SUCCESS);
 138 }
 139
 140 /*
 141  * account management
 142  */
 143 PAM_EXTERN int
 144 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused,
 145     int argc __unused, const char *argv[] __unused)
 146 {
 147         struct addrinfo hints, *res;
 148         struct passwd *pwd;
 149         struct timeval tp;
 150         login_cap_t *lc;
 151         time_t warntime;
 152         int retval;
 153         const char *user;
 154         const void *rhost, *tty;
 155         char rhostip[MAXHOSTNAMELEN] = "";
 156
 157         retval = pam_get_user(pamh, &user, NULL);
 158         if (retval != PAM_SUCCESS)
 159                 return (retval);
 160
 161         if (user == NULL || (pwd = getpwnam(user)) == NULL)
 162                 return (PAM_SERVICE_ERR);
 163
 164         PAM_LOG("Got user: %s", user);
 165
 166         retval = pam_get_item(pamh, PAM_RHOST, &rhost);
 167         if (retval != PAM_SUCCESS)
 168                 return (retval);
 169
 170         retval = pam_get_item(pamh, PAM_TTY, &tty);
 171         if (retval != PAM_SUCCESS)
 172                 return (retval);
 173
 174         if (*pwd->pw_passwd == '\0' &&
 175             (flags & PAM_DISALLOW_NULL_AUTHTOK) != 0)
 176                 return (PAM_NEW_AUTHTOK_REQD);
 177
 178         lc = login_getpwclass(pwd);
 179         if (lc == NULL) {
 180                 PAM_LOG("Unable to get login class for user %s", user);
 181                 return (PAM_SERVICE_ERR);
 182         }
 183
 184         PAM_LOG("Got login_cap");
 185
 186         if (pwd->pw_change || pwd->pw_expire)
 187                 gettimeofday(&tp, NULL);
 188
 189         /*
 190          * Check pw_expire before pw_change - no point in letting the
 191          * user change the password on an expired account.
 192          */
 193
 194         if (pwd->pw_expire) {
 195                 warntime = login_getcaptime(lc, "warnexpire",
 196                     DEFAULT_WARN, DEFAULT_WARN);
 197                 if (tp.tv_sec >= pwd->pw_expire) {
 198                         login_close(lc);
 199                         return (PAM_ACCT_EXPIRED);
 200                 } else if (pwd->pw_expire - tp.tv_sec < warntime &&
 201                     (flags & PAM_SILENT) == 0) {
 202                         pam_error(pamh, "Warning: your account expires on %s",
 203                             ctime(&pwd->pw_expire));
 204                 }
 205         }
 206
 207         retval = PAM_SUCCESS;
 208         if (pwd->pw_change) {
 209                 warntime = login_getcaptime(lc, "warnpassword",
 210                     DEFAULT_WARN, DEFAULT_WARN);
 211                 if (tp.tv_sec >= pwd->pw_change) {
 212                         retval = PAM_NEW_AUTHTOK_REQD;
 213                 } else if (pwd->pw_change - tp.tv_sec < warntime &&
 214                     (flags & PAM_SILENT) == 0) {
 215                         pam_error(pamh, "Warning: your password expires on %s",
 216                             ctime(&pwd->pw_change));
 217                 }
 218         }
 219
 220         /*
 221          * From here on, we must leave retval untouched (unless we
 222          * know we're going to fail), because we need to remember
 223          * whether we're supposed to return PAM_SUCCESS or
 224          * PAM_NEW_AUTHTOK_REQD.
 225          */
 226
 227         if (rhost && *(const char *)rhost != '\0') {
 228                 memset(&hints, 0, sizeof(hints));
 229                 hints.ai_family = AF_UNSPEC;
 230                 if (getaddrinfo(rhost, NULL, &hints, &res) == 0) {
 231                         getnameinfo(res->ai_addr, res->ai_addrlen,
 232                             rhostip, sizeof(rhostip), NULL, 0,
 233                             NI_NUMERICHOST);
 234                 }
 235                 if (res != NULL)
 236                         freeaddrinfo(res);
 237         }
 238
 239         /*
 240          * Check host / tty / time-of-day restrictions
 241          */
 242
 243         if (!auth_hostok(lc, rhost, rhostip) ||
 244             !auth_ttyok(lc, tty) ||
 245             !auth_timeok(lc, time(NULL)))
 246                 retval = PAM_AUTH_ERR;
 247
 248         login_close(lc);
 249
 250         return (retval);
 251 }
 252
 253 /*
 254  * password management
 255  *
 256  * standard Unix and NIS password changing
 257  */
 258 PAM_EXTERN int
 259 pam_sm_chauthtok(pam_handle_t *pamh, int flags,
 260     int argc __unused, const char *argv[] __unused)
 261 {
 262 #ifdef YP
 263         struct ypclnt *ypclnt;
 264         const void *yp_domain, *yp_server;
 265 #endif
 266         char salt[SALTSIZE + 1];
 267         login_cap_t * lc;
 268         struct passwd *pwd, *old_pwd;
 269         const char *user, *old_pass, *new_pass;
 270         char *encrypted;
 271         int pfd, tfd, retval = PAM_ABORT;
 272
 273         if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF))
 274                 pwd = getpwnam(getlogin());
 275         else {
 276                 retval = pam_get_user(pamh, &user, NULL);
 277                 if (retval != PAM_SUCCESS)
 278                         return (retval);
 279                 pwd = getpwnam(user);
 280         }
 281
 282         if (pwd == NULL)
 283                 return (PAM_AUTHTOK_RECOVERY_ERR);
 284
 285         PAM_LOG("Got user: %s", user);
 286
 287         if (flags & PAM_PRELIM_CHECK) {
 288
 289                 PAM_LOG("PRELIM round");
 290
 291                 if (getuid() == 0
 292 #if 0
 293                     && (pwd->pw_fields & _PWF_SOURCE) == _PWF_FILES
 294 #endif
 295                     )
 296                         /* root doesn't need the old password */
 297                         return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
 298 #ifdef YP
 299                 if (getuid() == 0
 300 #if 0
 301                     && (pwd->pw_fields & _PWF_SOURCE) == _PWF_NIS
 302 #endif
 303                     ) {
 304
 305                         yp_domain = yp_server = NULL;
 306                         (void)pam_get_data(pamh, "yp_domain", &yp_domain);
 307                         (void)pam_get_data(pamh, "yp_server", &yp_server);
 308
 309                         ypclnt = ypclnt_new(yp_domain, "passwd.byname", yp_server);
 310                         if (ypclnt == NULL)
 311                                 return (PAM_BUF_ERR);
 312
 313                         if (ypclnt_connect(ypclnt) == -1) {
 314                                 ypclnt_free(ypclnt);
 315                                 return (PAM_SERVICE_ERR);
 316                         }
 317
 318                         retval = ypclnt_havepasswdd(ypclnt);
 319                         ypclnt_free(ypclnt);
 320                         if (retval == 1)
 321                                 return (pam_set_item(pamh, PAM_OLDAUTHTOK, ""));
 322                         else if (retval == -1)
 323                                 return (PAM_SERVICE_ERR);
 324                 }
 325 #endif
 326                 if (pwd->pw_passwd[0] == '\0'
 327                     && openpam_get_option(pamh, PAM_OPT_NULLOK)) {
 328                         /*
 329                          * No password case. XXX Are we giving too much away
 330                          * by not prompting for a password?
 331                          * XXX check PAM_DISALLOW_NULL_AUTHTOK
 332                          */
 333                         old_pass = "";
 334                 } else {
 335                         retval = pam_get_authtok(pamh,
 336                             PAM_OLDAUTHTOK, &old_pass, NULL);
 337                         if (retval != PAM_SUCCESS)
 338                                 return (retval);
 339                 }
 340                 PAM_LOG("Got old password");
 341                 /* always encrypt first */
 342                 encrypted = crypt(old_pass, pwd->pw_passwd);
 343                 if (old_pass[0] == '\0' &&
 344                     !openpam_get_option(pamh, PAM_OPT_NULLOK))
 345                         return (PAM_PERM_DENIED);
 346                 if (strcmp(encrypted, pwd->pw_passwd) != 0)
 347                         return (PAM_PERM_DENIED);
 348         }
 349         else if (flags & PAM_UPDATE_AUTHTOK) {
 350                 PAM_LOG("UPDATE round");
 351
 352                 retval = pam_get_authtok(pamh,
 353                     PAM_OLDAUTHTOK, &old_pass, NULL);
 354                 if (retval != PAM_SUCCESS)
 355                         return (retval);
 356                 PAM_LOG("Got old password");
 357
 358                 /* get new password */
 359                 for (;;) {
 360                         retval = pam_get_authtok(pamh,
 361                             PAM_AUTHTOK, &new_pass, NULL);
 362                         if (retval != PAM_TRY_AGAIN)
 363                                 break;
 364                         pam_error(pamh, "Mismatch; try again, EOF to quit.");
 365                 }
 366                 PAM_LOG("Got new password");
 367                 if (retval != PAM_SUCCESS) {
 368                         PAM_VERBOSE_ERROR("Unable to get new password");
 369                         return (retval);
 370                 }
 371
 372                 if (getuid() != 0 && new_pass[0] == '\0' &&
 373                     !openpam_get_option(pamh, PAM_OPT_NULLOK))
 374                         return (PAM_PERM_DENIED);
 375
 376                 if ((old_pwd = pw_dup(pwd)) == NULL)
 377                         return (PAM_BUF_ERR);
 378
 379                 pwd->pw_change = 0;
 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                 login_close(lc);
 385                 makesalt(salt);
 386                 pwd->pw_passwd = crypt(new_pass, salt);
 387 #ifdef YP
 388                 switch (old_pwd->pw_fields & _PWF_SOURCE) {
 389                 case _PWF_FILES:
 390 #endif
 391                         retval = PAM_SERVICE_ERR;
 392                         if (pw_init(NULL, NULL))
 393                                 openpam_log(PAM_LOG_ERROR, "pw_init() failed");
 394                         else if ((pfd = pw_lock()) == -1)
 395                                 openpam_log(PAM_LOG_ERROR, "pw_lock() failed");
 396                         else if ((tfd = pw_tmp(-1)) == -1)
 397                                 openpam_log(PAM_LOG_ERROR, "pw_tmp() failed");
 398                         else if (pw_copy(pfd, tfd, pwd, old_pwd) == -1)
 399                                 openpam_log(PAM_LOG_ERROR, "pw_copy() failed");
 400                         else if (pw_mkdb(pwd->pw_name) == -1)
 401                                 openpam_log(PAM_LOG_ERROR, "pw_mkdb() failed");
 402                         else
 403                                 retval = PAM_SUCCESS;
 404                         pw_fini();
 405 #ifdef YP
 406                         break;
 407                 case _PWF_NIS:
 408                         yp_domain = yp_server = NULL;
 409                         (void)pam_get_data(pamh, "yp_domain", &yp_domain);
 410                         (void)pam_get_data(pamh, "yp_server", &yp_server);
 411                         ypclnt = ypclnt_new(yp_domain,
 412                             "passwd.byname", yp_server);
 413                         if (ypclnt == NULL) {
 414                                 retval = PAM_BUF_ERR;
 415                         } else if (ypclnt_connect(ypclnt) == -1 ||
 416                             ypclnt_passwd(ypclnt, pwd, old_pass) == -1) {
 417                                 openpam_log(PAM_LOG_ERROR, "%s", ypclnt->error);
 418                                 retval = PAM_SERVICE_ERR;
 419                         } else {
 420                                 retval = PAM_SUCCESS;
 421                         }
 422                         ypclnt_free(ypclnt);
 423                         break;
 424                 default:
 425                         openpam_log(PAM_LOG_ERROR, "unsupported source 0x%x",
 426                             pwd->pw_fields & _PWF_SOURCE);
 427                         retval = PAM_SERVICE_ERR;
 428                 }
 429 #endif
 430                 free(old_pwd);
 431         }
 432         else {
 433                 /* Very bad juju */
 434                 retval = PAM_ABORT;
 435                 PAM_LOG("Illegal 'flags'");
 436         }
 437
 438         return (retval);
 439 }
 440
 441 /* Mostly stolen from passwd(1)'s local_passwd.c - markm */
 442
 443 static unsigned char itoa64[] =         /* 0 ... 63 => ascii - 64 */
 444         "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
 445
 446 static void
 447 to64(char *s, long v, int n)
 448 {
 449         while (--n >= 0) {
 450                 *s++ = itoa64[v&0x3f];
 451                 v >>= 6;
 452         }
 453 }
 454
 455 /* Salt suitable for traditional DES and MD5 */
 456 void
 457 makesalt(char salt[SALTSIZE])
 458 {
 459         int i;
 460
 461         /* These are not really random numbers, they are just
 462          * numbers that change to thwart construction of a
 463          * dictionary. This is exposed to the public.
 464          */
 465         for (i = 0; i < SALTSIZE; i += 4)
 466                 to64(&salt[i], arc4random(), 4);
 467         salt[SALTSIZE] = '\0';
 468 }
 469
 470 PAM_MODULE_ENTRY("pam_unix");