source3/nsswitch/pam_winbind.c

   1 /* pam_winbind module
   2
   3    Copyright Andrew Tridgell <tridge@samba.org> 2000
   4    Copyright Tim Potter <tpot@samba.org> 2000
   5    Copyright Andrew Bartlett <abartlet@samba.org> 2002
   6
   7    largely based on pam_userdb by Christian Gafton <gafton@redhat.com>
   8    also contains large slabs of code from pam_unix by Elliot Lee <sopwith@redhat.com>
   9    (see copyright below for full details)
  10 */
  11
  12 #include "pam_winbind.h"
  13
  14 /* data tokens */
  15
  16 #define MAX_PASSWD_TRIES        3
  17
  18 /* some syslogging */
  19 static void _pam_log(int err, const char *format, ...)
  20 {
  21         va_list args;
  22
  23         va_start(args, format);
  24         openlog(MODULE_NAME, LOG_CONS|LOG_PID, LOG_AUTH);
  25         vsyslog(err, format, args);
  26         va_end(args);
  27         closelog();
  28 }
  29
  30 static int _pam_parse(int argc, const char **argv)
  31 {
  32         int ctrl;
  33         /* step through arguments */
  34         for (ctrl = 0; argc-- > 0; ++argv) {
  35
  36                 /* generic options */
  37
  38                 if (!strcmp(*argv,"debug"))
  39                         ctrl |= WINBIND_DEBUG_ARG;
  40                 else if (!strcasecmp(*argv, "use_authtok"))
  41                         ctrl |= WINBIND_USE_AUTHTOK_ARG;
  42                 else if (!strcasecmp(*argv, "use_first_pass"))
  43                         ctrl |= WINBIND_USE_FIRST_PASS_ARG;
  44                 else if (!strcasecmp(*argv, "try_first_pass"))
  45                         ctrl |= WINBIND_TRY_FIRST_PASS_ARG;
  46                 else if (!strcasecmp(*argv, "unknown_ok"))
  47                         ctrl |= WINBIND_UNKNOWN_OK_ARG;
  48                 else {
  49                         _pam_log(LOG_ERR, "pam_parse: unknown option; %s", *argv);
  50                 }
  51         }
  52
  53         return ctrl;
  54 }
  55
  56 /* --- authentication management functions --- */
  57
  58 /* Attempt a conversation */
  59
  60 static int converse(pam_handle_t *pamh, int nargs,
  61                     struct pam_message **message,
  62                     struct pam_response **response)
  63 {
  64     int retval;
  65     struct pam_conv *conv;
  66
  67     retval = pam_get_item(pamh, PAM_CONV, (const void **) &conv ) ;
  68     if (retval == PAM_SUCCESS) {
  69         retval = conv->conv(nargs, (const struct pam_message **)message,
  70                             response, conv->appdata_ptr);
  71     }
  72
  73     return retval; /* propagate error status */
  74 }
  75
  76
  77 static int _make_remark(pam_handle_t * pamh, int type, const char *text)
  78 {
  79         int retval = PAM_SUCCESS;
  80
  81         struct pam_message *pmsg[1], msg[1];
  82         struct pam_response *resp;
  83
  84         pmsg[0] = &msg[0];
  85         msg[0].msg = text;
  86         msg[0].msg_style = type;
  87
  88         resp = NULL;
  89         retval = converse(pamh, 1, pmsg, &resp);
  90
  91         if (resp) {
  92                 _pam_drop_reply(resp, 1);
  93         }
  94         return retval;
  95 }
  96
  97 static int pam_winbind_request(enum winbindd_cmd req_type,
  98                                struct winbindd_request *request,
  99                                struct winbindd_response *response)
 100 {
 101
 102         /* Fill in request and send down pipe */
 103         init_request(request, req_type);
 104
 105         if (write_sock(request, sizeof(*request)) == -1) {
 106                 _pam_log(LOG_ERR, "write to socket failed!");
 107                 close_sock();
 108                 return PAM_SERVICE_ERR;
 109         }
 110
 111         /* Wait for reply */
 112         if (read_reply(response) == -1) {
 113                 _pam_log(LOG_ERR, "read from socket failed!");
 114                 close_sock();
 115                 return PAM_SERVICE_ERR;
 116         }
 117
 118         /* We are done with the socket - close it and avoid mischeif */
 119         close_sock();
 120
 121         /* Copy reply data from socket */
 122         if (response->result != WINBINDD_OK) {
 123                 if (response->data.auth.pam_error != PAM_SUCCESS) {
 124                         _pam_log(LOG_ERR, "request failed, PAM error was %d, NT error was %s",
 125                                  response->data.auth.pam_error,
 126                                  response->data.auth.nt_status_string);
 127                         return response->data.auth.pam_error;
 128                 } else {
 129                         _pam_log(LOG_ERR, "request failed, but PAM error 0!");
 130                         return PAM_SERVICE_ERR;
 131                 }
 132         }
 133
 134         return PAM_SUCCESS;
 135 }
 136
 137 /* talk to winbindd */
 138 static int winbind_auth_request(const char *user, const char *pass, int ctrl)
 139 {
 140         struct winbindd_request request;
 141         struct winbindd_response response;
 142         int retval;
 143
 144         ZERO_STRUCT(request);
 145
 146         strncpy(request.data.auth.user, user,
 147                 sizeof(request.data.auth.user)-1);
 148
 149         strncpy(request.data.auth.pass, pass,
 150                 sizeof(request.data.auth.pass)-1);
 151
 152         retval = pam_winbind_request(WINBINDD_PAM_AUTH, &request, &response);
 153
 154         switch (retval) {
 155         case PAM_AUTH_ERR:
 156                 /* incorrect password */
 157                 _pam_log(LOG_WARNING, "user `%s' denied access (incorrect password)", user);
 158                 return retval;
 159         case PAM_ACCT_EXPIRED:
 160                 /* account expired */
 161                 _pam_log(LOG_WARNING, "user `%s' account expired", user);
 162                 return retval;
 163         case PAM_AUTHTOK_EXPIRED:
 164                 /* password expired */
 165                 _pam_log(LOG_WARNING, "user `%s' password expired", user);
 166                 return retval;
 167         case PAM_NEW_AUTHTOK_REQD:
 168                 /* password expired */
 169                 _pam_log(LOG_WARNING, "user `%s' new password required", user);
 170                 return retval;
 171         case PAM_USER_UNKNOWN:
 172                 /* the user does not exist */
 173                 if (ctrl & WINBIND_DEBUG_ARG)
 174                         _pam_log(LOG_NOTICE, "user `%s' not found",
 175                                  user);
 176                 if (ctrl & WINBIND_UNKNOWN_OK_ARG) {
 177                         return PAM_IGNORE;
 178                 }
 179                 return retval;
 180         case PAM_SUCCESS:
 181                 /* Otherwise, the authentication looked good */
 182                 _pam_log(LOG_NOTICE, "user '%s' granted acces", user);
 183                 return retval;
 184         default:
 185                 /* we don't know anything about this return value */
 186                 _pam_log(LOG_ERR, "internal module error (retval = %d, user = `%s'",
 187                          retval, user);
 188                 return retval;
 189         }
 190      /* should not be reached */
 191 }
 192
 193 /* talk to winbindd */
 194 static int winbind_chauthtok_request(const char *user, const char *oldpass,
 195                                      const char *newpass)
 196 {
 197         struct winbindd_request request;
 198         struct winbindd_response response;
 199
 200         ZERO_STRUCT(request);
 201
 202         if (request.data.chauthtok.user == NULL) return -2;
 203
 204         strncpy(request.data.chauthtok.user, user,
 205                 sizeof(request.data.chauthtok.user) - 1);
 206
 207         if (oldpass != NULL) {
 208             strncpy(request.data.chauthtok.oldpass, oldpass,
 209                     sizeof(request.data.chauthtok.oldpass) - 1);
 210         } else {
 211             request.data.chauthtok.oldpass[0] = '\0';
 212         }
 213
 214         if (newpass != NULL) {
 215             strncpy(request.data.chauthtok.newpass, newpass,
 216                     sizeof(request.data.chauthtok.newpass) - 1);
 217         } else {
 218             request.data.chauthtok.newpass[0] = '\0';
 219         }
 220
 221         return pam_winbind_request(WINBINDD_PAM_CHAUTHTOK, &request, &response);
 222 }
 223
 224 /*
 225  * Checks if a user has an account
 226  *
 227  * return values:
 228  *       1  = User not found
 229  *       0  = OK
 230  *      -1  = System error
 231  */
 232 static int valid_user(const char *user)
 233 {
 234         if (getpwnam(user)) return 0;
 235         return 1;
 236 }
 237
 238 static char *_pam_delete(register char *xx)
 239 {
 240     _pam_overwrite(xx);
 241     _pam_drop(xx);
 242     return NULL;
 243 }
 244
 245 /*
 246  * obtain a password from the user
 247  */
 248
 249 static int _winbind_read_password(pam_handle_t * pamh
 250                                   ,unsigned int ctrl
 251                                   ,const char *comment
 252                                   ,const char *prompt1
 253                                   ,const char *prompt2
 254                                   ,const char **pass)
 255 {
 256         int authtok_flag;
 257         int retval;
 258         const char *item;
 259         char *token;
 260
 261         /*
 262          * make sure nothing inappropriate gets returned
 263          */
 264
 265         *pass = token = NULL;
 266
 267         /*
 268          * which authentication token are we getting?
 269          */
 270
 271         authtok_flag = on(WINBIND__OLD_PASSWORD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK;
 272
 273         /*
 274          * should we obtain the password from a PAM item ?
 275          */
 276
 277         if (on(WINBIND_TRY_FIRST_PASS_ARG, ctrl) || on(WINBIND_USE_FIRST_PASS_ARG, ctrl)) {
 278                 retval = pam_get_item(pamh, authtok_flag, (const void **) &item);
 279                 if (retval != PAM_SUCCESS) {
 280                         /* very strange. */
 281                         _pam_log(LOG_ALERT,
 282                                  "pam_get_item returned error to unix-read-password"
 283                             );
 284                         return retval;
 285                 } else if (item != NULL) {      /* we have a password! */
 286                         *pass = item;
 287                         item = NULL;
 288                         return PAM_SUCCESS;
 289                 } else if (on(WINBIND_USE_FIRST_PASS_ARG, ctrl)) {
 290                         return PAM_AUTHTOK_RECOVER_ERR;         /* didn't work */
 291                 } else if (on(WINBIND_USE_AUTHTOK_ARG, ctrl)
 292                            && off(WINBIND__OLD_PASSWORD, ctrl)) {
 293                         return PAM_AUTHTOK_RECOVER_ERR;
 294                 }
 295         }
 296         /*
 297          * getting here implies we will have to get the password from the
 298          * user directly.
 299          */
 300
 301         {
 302                 struct pam_message msg[3], *pmsg[3];
 303                 struct pam_response *resp;
 304                 int i, replies;
 305
 306                 /* prepare to converse */
 307
 308                 if (comment != NULL) {
 309                         pmsg[0] = &msg[0];
 310                         msg[0].msg_style = PAM_TEXT_INFO;
 311                         msg[0].msg = comment;
 312                         i = 1;
 313                 } else {
 314                         i = 0;
 315                 }
 316
 317                 pmsg[i] = &msg[i];
 318                 msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 319                 msg[i++].msg = prompt1;
 320                 replies = 1;
 321
 322                 if (prompt2 != NULL) {
 323                         pmsg[i] = &msg[i];
 324                         msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 325                         msg[i++].msg = prompt2;
 326                         ++replies;
 327                 }
 328                 /* so call the conversation expecting i responses */
 329                 resp = NULL;
 330                 retval = converse(pamh, i, pmsg, &resp);
 331
 332                 if (resp != NULL) {
 333
 334                         /* interpret the response */
 335
 336                         if (retval == PAM_SUCCESS) {    /* a good conversation */
 337
 338                                 token = x_strdup(resp[i - replies].resp);
 339                                 if (token != NULL) {
 340                                         if (replies == 2) {
 341
 342                                                 /* verify that password entered correctly */
 343                                                 if (!resp[i - 1].resp
 344                                                     || strcmp(token, resp[i - 1].resp)) {
 345                                                         _pam_delete(token);     /* mistyped */
 346                                                         retval = PAM_AUTHTOK_RECOVER_ERR;
 347                                                         _make_remark(pamh                                                                   ,PAM_ERROR_MSG, MISTYPED_PASS);
 348                                                 }
 349                                         }
 350                                 } else {
 351                                         _pam_log(LOG_NOTICE
 352                                                  ,"could not recover authentication token");
 353                                 }
 354
 355                         }
 356                         /*
 357                          * tidy up the conversation (resp_retcode) is ignored
 358                          * -- what is it for anyway? AGM
 359                          */
 360
 361                         _pam_drop_reply(resp, i);
 362
 363                 } else {
 364                         retval = (retval == PAM_SUCCESS)
 365                             ? PAM_AUTHTOK_RECOVER_ERR : retval;
 366                 }
 367         }
 368
 369         if (retval != PAM_SUCCESS) {
 370                 if (on(WINBIND_DEBUG_ARG, ctrl))
 371                         _pam_log(LOG_DEBUG,
 372                                  "unable to obtain a password");
 373                 return retval;
 374         }
 375         /* 'token' is the entered password */
 376
 377         /* we store this password as an item */
 378
 379         retval = pam_set_item(pamh, authtok_flag, token);
 380         _pam_delete(token);     /* clean it up */
 381         if (retval != PAM_SUCCESS
 382             || (retval = pam_get_item(pamh, authtok_flag
 383                                       ,(const void **) &item))
 384             != PAM_SUCCESS) {
 385
 386                 _pam_log(LOG_CRIT, "error manipulating password");
 387                 return retval;
 388
 389         }
 390
 391         *pass = item;
 392         item = NULL;            /* break link to password */
 393
 394         return PAM_SUCCESS;
 395 }
 396
 397 PAM_EXTERN
 398 int pam_sm_authenticate(pam_handle_t *pamh, int flags,
 399                         int argc, const char **argv)
 400 {
 401      const char *username;
 402      const char *password;
 403      int retval = PAM_AUTH_ERR;
 404
 405      /* parse arguments */
 406      int ctrl = _pam_parse(argc, argv);
 407
 408      /* Get the username */
 409      retval = pam_get_user(pamh, &username, NULL);
 410      if ((retval != PAM_SUCCESS) || (!username)) {
 411         if (ctrl & WINBIND_DEBUG_ARG)
 412             _pam_log(LOG_DEBUG,"can not get the username");
 413         return PAM_SERVICE_ERR;
 414      }
 415
 416      retval = _winbind_read_password(pamh, ctrl, NULL,
 417                                      "Password: ", NULL,
 418                                      &password);
 419
 420      if (retval != PAM_SUCCESS) {
 421          _pam_log(LOG_ERR, "Could not retrieve user's password");
 422          return PAM_AUTHTOK_ERR;
 423      }
 424
 425      if (ctrl & WINBIND_DEBUG_ARG) {
 426
 427              /* Let's not give too much away in the log file */
 428
 429 #ifdef DEBUG_PASSWORD
 430          _pam_log(LOG_INFO, "Verify user `%s' with password `%s'",
 431                   username, password);
 432 #else
 433          _pam_log(LOG_INFO, "Verify user `%s'", username);
 434 #endif
 435      }
 436
 437      /* Now use the username to look up password */
 438      return winbind_auth_request(username, password, ctrl);
 439 }
 440
 441 PAM_EXTERN
 442 int pam_sm_setcred(pam_handle_t *pamh, int flags,
 443                    int argc, const char **argv)
 444 {
 445     return PAM_SUCCESS;
 446 }
 447
 448 /*
 449  * Account management. We want to verify that the account exists
 450  * before returning PAM_SUCCESS
 451  */
 452 PAM_EXTERN
 453 int pam_sm_acct_mgmt(pam_handle_t *pamh, int flags,
 454                    int argc, const char **argv)
 455 {
 456     const char *username;
 457     int retval = PAM_USER_UNKNOWN;
 458
 459     /* parse arguments */
 460     int ctrl = _pam_parse(argc, argv);
 461
 462     /* Get the username */
 463     retval = pam_get_user(pamh, &username, NULL);
 464     if ((retval != PAM_SUCCESS) || (!username)) {
 465         if (ctrl & WINBIND_DEBUG_ARG)
 466             _pam_log(LOG_DEBUG,"can not get the username");
 467         return PAM_SERVICE_ERR;
 468     }
 469
 470     /* Verify the username */
 471     retval = valid_user(username);
 472     switch (retval) {
 473         case -1:
 474             /* some sort of system error. The log was already printed */
 475             return PAM_SERVICE_ERR;
 476         case 1:
 477             /* the user does not exist */
 478             if (ctrl & WINBIND_DEBUG_ARG)
 479                 _pam_log(LOG_NOTICE, "user `%s' not found",
 480                          username);
 481             if (ctrl & WINBIND_UNKNOWN_OK_ARG)
 482                 return PAM_IGNORE;
 483             return PAM_USER_UNKNOWN;
 484         case 0:
 485             /* Otherwise, the authentication looked good */
 486             _pam_log(LOG_NOTICE, "user '%s' granted acces", username);
 487             return PAM_SUCCESS;
 488         default:
 489             /* we don't know anything about this return value */
 490             _pam_log(LOG_ERR, "internal module error (retval = %d, user = `%s'",
 491                      retval, username);
 492             return PAM_SERVICE_ERR;
 493     }
 494
 495     /* should not be reached */
 496     return PAM_IGNORE;
 497 }
 498 PAM_EXTERN
 499 int pam_sm_open_session(pam_handle_t *pamh, int flags,
 500                 int argc, const char **argv)
 501 {
 502         /* parse arguments */
 503         int ctrl = _pam_parse(argc, argv);
 504         if (ctrl & WINBIND_DEBUG_ARG)
 505               _pam_log(LOG_DEBUG,"libpam_winbind:pam_sm_open_session handler");
 506         return PAM_SUCCESS;
 507 }
 508 PAM_EXTERN
 509 int pam_sm_close_session(pam_handle_t *pamh, int flags,
 510                 int argc, const char **argv)
 511 {
 512         /* parse arguments */
 513         int ctrl = _pam_parse(argc, argv);
 514         if (ctrl & WINBIND_DEBUG_ARG)
 515               _pam_log(LOG_DEBUG,"libpam_winbind:pam_sm_close_session handler");
 516         return PAM_SUCCESS;
 517 }
 518
 519
 520
 521 PAM_EXTERN int pam_sm_chauthtok(pam_handle_t * pamh, int flags,
 522                                 int argc, const char **argv)
 523 {
 524         unsigned int lctrl;
 525         int retval;
 526         unsigned int ctrl = _pam_parse(argc, argv);
 527
 528         /* <DO NOT free() THESE> */
 529         const char *user;
 530         char *pass_old, *pass_new;
 531         /* </DO NOT free() THESE> */
 532
 533         char *Announce;
 534
 535         int retry = 0;
 536
 537         /*
 538          * First get the name of a user
 539          */
 540         retval = pam_get_user(pamh, &user, "Username: ");
 541         if (retval == PAM_SUCCESS) {
 542                 if (user == NULL) {
 543                         _pam_log(LOG_ERR, "username was NULL!");
 544                         return PAM_USER_UNKNOWN;
 545                 }
 546                 if (retval == PAM_SUCCESS && on(WINBIND_DEBUG_ARG, ctrl))
 547                         _pam_log(LOG_DEBUG, "username [%s] obtained",
 548                                  user);
 549         } else {
 550                 if (on(WINBIND_DEBUG_ARG, ctrl))
 551                         _pam_log(LOG_DEBUG,
 552                                  "password - could not identify user");
 553                 return retval;
 554         }
 555
 556         /*
 557          * obtain and verify the current password (OLDAUTHTOK) for
 558          * the user.
 559          */
 560
 561         if (flags & PAM_PRELIM_CHECK) {
 562
 563                 /* instruct user what is happening */
 564 #define greeting "Changing password for "
 565                 Announce = (char *) malloc(sizeof(greeting) + strlen(user));
 566                 if (Announce == NULL) {
 567                 _pam_log(LOG_CRIT,
 568                          "password - out of memory");
 569                 return PAM_BUF_ERR;
 570                 }
 571                 (void) strcpy(Announce, greeting);
 572                 (void) strcpy(Announce + sizeof(greeting) - 1, user);
 573 #undef greeting
 574
 575                 lctrl = ctrl | WINBIND__OLD_PASSWORD;
 576                 retval = _winbind_read_password(pamh, lctrl
 577                                                 ,Announce
 578                                                 ,"(current) NT password: "
 579                                                 ,NULL
 580                                                 ,(const char **) &pass_old);
 581                 free(Announce);
 582
 583                 if (retval != PAM_SUCCESS) {
 584                         _pam_log(LOG_NOTICE
 585                                  ,"password - (old) token not obtained");
 586                         return retval;
 587                 }
 588                 /* verify that this is the password for this user */
 589
 590                 retval = winbind_auth_request(user, pass_old, ctrl);
 591
 592                 if (retval != PAM_ACCT_EXPIRED
 593                     && retval != PAM_AUTHTOK_EXPIRED
 594                     && retval != PAM_NEW_AUTHTOK_REQD
 595                     && retval != PAM_SUCCESS) {
 596                         pass_old = NULL;
 597                         return retval;
 598                 }
 599
 600                 retval = pam_set_item(pamh, PAM_OLDAUTHTOK, (const void *) pass_old);
 601                 pass_old = NULL;
 602                 if (retval != PAM_SUCCESS) {
 603                         _pam_log(LOG_CRIT,
 604                                  "failed to set PAM_OLDAUTHTOK");
 605                 }
 606         } else if (flags & PAM_UPDATE_AUTHTOK) {
 607
 608                 /*
 609                  * obtain the proposed password
 610                  */
 611
 612                 /*
 613                  * get the old token back.
 614                  */
 615
 616                 retval = pam_get_item(pamh, PAM_OLDAUTHTOK
 617                                       ,(const void **) &pass_old);
 618
 619                 if (retval != PAM_SUCCESS) {
 620                         _pam_log(LOG_NOTICE, "user not authenticated");
 621                         return retval;
 622                 }
 623
 624                 lctrl = ctrl;
 625
 626                 if (on(WINBIND_USE_AUTHTOK_ARG, lctrl)) {
 627                         ctrl = WINBIND_USE_FIRST_PASS_ARG | lctrl;
 628                 }
 629                 retry = 0;
 630                 retval = PAM_AUTHTOK_ERR;
 631                 while ((retval != PAM_SUCCESS) && (retry++ < MAX_PASSWD_TRIES)) {
 632                         /*
 633                          * use_authtok is to force the use of a previously entered
 634                          * password -- needed for pluggable password strength checking
 635                          */
 636
 637                         retval = _winbind_read_password(pamh, lctrl
 638                                                         ,NULL
 639                                                         ,"Enter new NT password: "
 640                                                         ,"Retype new NT password: "
 641                                                         ,(const char **) &pass_new);
 642
 643                         if (retval != PAM_SUCCESS) {
 644                                 if (on(WINBIND_DEBUG_ARG, ctrl)) {
 645                                         _pam_log(LOG_ALERT
 646                                                  ,"password - new password not obtained");
 647                                 }
 648                                 pass_old = NULL;/* tidy up */
 649                                 return retval;
 650                         }
 651
 652                         /*
 653                          * At this point we know who the user is and what they
 654                          * propose as their new password. Verify that the new
 655                          * password is acceptable.
 656                          */
 657
 658                         if (pass_new[0] == '\0') {/* "\0" password = NULL */
 659                                 pass_new = NULL;
 660                         }
 661                 }
 662
 663                 /*
 664                  * By reaching here we have approved the passwords and must now
 665                  * rebuild the password database file.
 666                  */
 667
 668                 retval = winbind_chauthtok_request(user, pass_old, pass_new);
 669                 _pam_overwrite(pass_new);
 670                 _pam_overwrite(pass_old);
 671                 pass_old = pass_new = NULL;
 672         } else {
 673                 retval = PAM_SERVICE_ERR;
 674         }
 675
 676         return retval;
 677 }
 678
 679 #ifdef PAM_STATIC
 680
 681 /* static module data */
 682
 683 struct pam_module _pam_winbind_modstruct = {
 684      MODULE_NAME,
 685      pam_sm_authenticate,
 686      pam_sm_setcred,
 687      pam_sm_acct_mgmt,
 688      pam_sm_open_session,
 689      pam_sm_close_session,
 690      pam_sm_chauthtok
 691 };
 692
 693 #endif
 694
 695 /*
 696  * Copyright (c) Andrew Tridgell  <tridge@samba.org>   2000
 697  * Copyright (c) Tim Potter       <tpot@samba.org>     2000
 698  * Copyright (c) Andrew Bartlettt <abartlet@samba.org> 2002
 699  * Copyright (c) Jan Rêkorajski 1999.
 700  * Copyright (c) Andrew G. Morgan 1996-8.
 701  * Copyright (c) Alex O. Yuriev, 1996.
 702  * Copyright (c) Cristian Gafton 1996.
 703  * Copyright (C) Elliot Lee <sopwith@redhat.com> 1996, Red Hat Software.
 704  *
 705  * Redistribution and use in source and binary forms, with or without
 706  * modification, are permitted provided that the following conditions
 707  * are met:
 708  * 1. Redistributions of source code must retain the above copyright
 709  *    notice, and the entire permission notice in its entirety,
 710  *    including the disclaimer of warranties.
 711  * 2. Redistributions in binary form must reproduce the above copyright
 712  *    notice, this list of conditions and the following disclaimer in the
 713  *    documentation and/or other materials provided with the distribution.
 714  * 3. The name of the author may not be used to endorse or promote
 715  *    products derived from this software without specific prior
 716  *    written permission.
 717  *
 718  * ALTERNATIVELY, this product may be distributed under the terms of
 719  * the GNU Public License, in which case the provisions of the GPL are
 720  * required INSTEAD OF the above restrictions.  (This clause is
 721  * necessary due to a potential bad interaction between the GPL and
 722  * the restrictions contained in a BSD-style copyright.)
 723  *
 724  * THIS SOFTWARE IS PROVIDED `AS IS'' AND ANY EXPRESS OR IMPLIED
 725  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 726  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 727  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 728  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 729  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 730  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 731  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 732  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 733  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 734  * OF THE POSSIBILITY OF SUCH DAMAGE.
 735  */