source3/smbd/password.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Password and authentication handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2007.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "smbd/globals.h"
  23
  24 enum server_allocated_state { SERVER_ALLOCATED_REQUIRED_YES,
  25                                 SERVER_ALLOCATED_REQUIRED_NO,
  26                                 SERVER_ALLOCATED_REQUIRED_ANY};
  27
  28 static user_struct *get_valid_user_struct_internal(uint16 vuid,
  29                         enum server_allocated_state server_allocated)
  30 {
  31         user_struct *usp;
  32         int count=0;
  33
  34         if (vuid == UID_FIELD_INVALID)
  35                 return NULL;
  36
  37         for (usp=validated_users;usp;usp=usp->next,count++) {
  38                 if (vuid == usp->vuid) {
  39                         switch (server_allocated) {
  40                                 case SERVER_ALLOCATED_REQUIRED_YES:
  41                                         if (usp->server_info == NULL) {
  42                                                 continue;
  43                                         }
  44                                         break;
  45                                 case SERVER_ALLOCATED_REQUIRED_NO:
  46                                         if (usp->server_info != NULL) {
  47                                                 continue;
  48                                         }
  49                                 case SERVER_ALLOCATED_REQUIRED_ANY:
  50                                         break;
  51                         }
  52                         if (count > 10) {
  53                                 DLIST_PROMOTE(validated_users, usp);
  54                         }
  55                         return usp;
  56                 }
  57         }
  58
  59         return NULL;
  60 }
  61
  62 /****************************************************************************
  63  Check if a uid has been validated, and return an pointer to the user_struct
  64  if it has. NULL if not. vuid is biased by an offset. This allows us to
  65  tell random client vuid's (normally zero) from valid vuids.
  66 ****************************************************************************/
  67
  68 user_struct *get_valid_user_struct(uint16 vuid)
  69 {
  70         return get_valid_user_struct_internal(vuid,
  71                         SERVER_ALLOCATED_REQUIRED_YES);
  72 }
  73
  74 bool is_partial_auth_vuid(uint16 vuid)
  75 {
  76         return (get_partial_auth_user_struct(vuid) != NULL);
  77 }
  78
  79 /****************************************************************************
  80  Get the user struct of a partial NTLMSSP login
  81 ****************************************************************************/
  82
  83 user_struct *get_partial_auth_user_struct(uint16 vuid)
  84 {
  85         return get_valid_user_struct_internal(vuid,
  86                         SERVER_ALLOCATED_REQUIRED_NO);
  87 }
  88
  89 /****************************************************************************
  90  Invalidate a uid.
  91 ****************************************************************************/
  92
  93 void invalidate_vuid(uint16 vuid)
  94 {
  95         user_struct *vuser = NULL;
  96
  97         vuser = get_valid_user_struct_internal(vuid,
  98                         SERVER_ALLOCATED_REQUIRED_ANY);
  99         if (vuser == NULL) {
 100                 return;
 101         }
 102
 103         session_yield(vuser);
 104
 105         if (vuser->auth_ntlmssp_state) {
 106                 auth_ntlmssp_end(&vuser->auth_ntlmssp_state);
 107         }
 108
 109         DLIST_REMOVE(validated_users, vuser);
 110
 111         /* clear the vuid from the 'cache' on each connection, and
 112            from the vuid 'owner' of connections */
 113         conn_clear_vuid_caches(vuid);
 114
 115         TALLOC_FREE(vuser);
 116         num_validated_vuids--;
 117 }
 118
 119 /****************************************************************************
 120  Invalidate all vuid entries for this process.
 121 ****************************************************************************/
 122
 123 void invalidate_all_vuids(void)
 124 {
 125         while (validated_users != NULL) {
 126                 invalidate_vuid(validated_users->vuid);
 127         }
 128 }
 129
 130 static void increment_next_vuid(uint16_t *vuid)
 131 {
 132         *vuid += 1;
 133
 134         /* Check for vuid wrap. */
 135         if (*vuid == UID_FIELD_INVALID) {
 136                 *vuid = VUID_OFFSET;
 137         }
 138 }
 139
 140 /****************************************************
 141  Create a new partial auth user struct.
 142 *****************************************************/
 143
 144 int register_initial_vuid(void)
 145 {
 146         user_struct *vuser;
 147
 148         /* Paranoia check. */
 149         if(lp_security() == SEC_SHARE) {
 150                 smb_panic("register_initial_vuid: "
 151                         "Tried to register uid in security=share");
 152         }
 153
 154         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 155         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 156                 return UID_FIELD_INVALID;
 157         }
 158
 159         if((vuser = talloc_zero(NULL, user_struct)) == NULL) {
 160                 DEBUG(0,("register_initial_vuid: "
 161                                 "Failed to talloc users struct!\n"));
 162                 return UID_FIELD_INVALID;
 163         }
 164
 165         /* Allocate a free vuid. Yes this is a linear search... */
 166         while( get_valid_user_struct_internal(next_vuid,
 167                         SERVER_ALLOCATED_REQUIRED_ANY) != NULL ) {
 168                 increment_next_vuid(&next_vuid);
 169         }
 170
 171         DEBUG(10,("register_initial_vuid: allocated vuid = %u\n",
 172                 (unsigned int)next_vuid ));
 173
 174         vuser->vuid = next_vuid;
 175
 176         /*
 177          * This happens in an unfinished NTLMSSP session setup. We
 178          * need to allocate a vuid between the first and second calls
 179          * to NTLMSSP.
 180          */
 181         increment_next_vuid(&next_vuid);
 182         num_validated_vuids++;
 183
 184         DLIST_ADD(validated_users, vuser);
 185         return vuser->vuid;
 186 }
 187
 188 static int register_homes_share(const char *username)
 189 {
 190         int result;
 191         struct passwd *pwd;
 192
 193         result = lp_servicenumber(username);
 194         if (result != -1) {
 195                 DEBUG(3, ("Using static (or previously created) service for "
 196                           "user '%s'; path = '%s'\n", username,
 197                           lp_pathname(result)));
 198                 return result;
 199         }
 200
 201         pwd = getpwnam_alloc(talloc_tos(), username);
 202
 203         if ((pwd == NULL) || (pwd->pw_dir[0] == '\0')) {
 204                 DEBUG(3, ("No home directory defined for user '%s'\n",
 205                           username));
 206                 TALLOC_FREE(pwd);
 207                 return -1;
 208         }
 209
 210         DEBUG(3, ("Adding homes service for user '%s' using home directory: "
 211                   "'%s'\n", username, pwd->pw_dir));
 212
 213         result = add_home_service(username, username, pwd->pw_dir);
 214
 215         TALLOC_FREE(pwd);
 216         return result;
 217 }
 218
 219 /**
 220  *  register that a valid login has been performed, establish 'session'.
 221  *  @param server_info The token returned from the authentication process.
 222  *   (now 'owned' by register_existing_vuid)
 223  *
 224  *  @param session_key The User session key for the login session (now also
 225  *  'owned' by register_existing_vuid)
 226  *
 227  *  @param respose_blob The NT challenge-response, if available.  (May be
 228  *  freed after this call)
 229  *
 230  *  @param smb_name The untranslated name of the user
 231  *
 232  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 233  *   tell random client vuid's (normally zero) from valid vuids.)
 234  *
 235  */
 236
 237 int register_existing_vuid(uint16 vuid,
 238                         auth_serversupplied_info *server_info,
 239                         DATA_BLOB response_blob,
 240                         const char *smb_name)
 241 {
 242         fstring tmp;
 243         user_struct *vuser;
 244
 245         vuser = get_partial_auth_user_struct(vuid);
 246         if (!vuser) {
 247                 goto fail;
 248         }
 249
 250         /* Use this to keep tabs on all our info from the authentication */
 251         vuser->server_info = talloc_move(vuser, &server_info);
 252
 253         /* This is a potentially untrusted username */
 254         alpha_strcpy(tmp, smb_name, ". _-$", sizeof(tmp));
 255
 256         vuser->server_info->sanitized_username = talloc_strdup(
 257                 vuser->server_info, tmp);
 258
 259         DEBUG(10,("register_existing_vuid: (%u,%u) %s %s %s guest=%d\n",
 260                   (unsigned int)vuser->server_info->utok.uid,
 261                   (unsigned int)vuser->server_info->utok.gid,
 262                   vuser->server_info->unix_name,
 263                   vuser->server_info->sanitized_username,
 264                   pdb_get_domain(vuser->server_info->sam_account),
 265                   vuser->server_info->guest ));
 266
 267         DEBUG(3, ("register_existing_vuid: User name: %s\t"
 268                   "Real name: %s\n", vuser->server_info->unix_name,
 269                   pdb_get_fullname(vuser->server_info->sam_account)));
 270
 271         if (!vuser->server_info->ptok) {
 272                 DEBUG(1, ("register_existing_vuid: server_info does not "
 273                         "contain a user_token - cannot continue\n"));
 274                 goto fail;
 275         }
 276
 277         DEBUG(3,("register_existing_vuid: UNIX uid %d is UNIX user %s, "
 278                 "and will be vuid %u\n", (int)vuser->server_info->utok.uid,
 279                  vuser->server_info->unix_name, vuser->vuid));
 280
 281         if (!session_claim(vuser)) {
 282                 DEBUG(1, ("register_existing_vuid: Failed to claim session "
 283                         "for vuid=%d\n",
 284                         vuser->vuid));
 285                 goto fail;
 286         }
 287
 288         /* Register a home dir service for this user if
 289         (a) This is not a guest connection,
 290         (b) we have a home directory defined
 291         (c) there s not an existing static share by that name
 292         If a share exists by this name (autoloaded or not) reuse it . */
 293
 294         vuser->homes_snum = -1;
 295
 296         if (!vuser->server_info->guest) {
 297                 vuser->homes_snum = register_homes_share(
 298                         vuser->server_info->unix_name);
 299         }
 300
 301         if (srv_is_signing_negotiated(smbd_server_conn) &&
 302             !vuser->server_info->guest) {
 303                 /* Try and turn on server signing on the first non-guest
 304                  * sessionsetup. */
 305                 srv_set_signing(smbd_server_conn,
 306                                 vuser->server_info->user_session_key,
 307                                 response_blob);
 308         }
 309
 310         /* fill in the current_user_info struct */
 311         set_current_user_info(
 312                 vuser->server_info->sanitized_username,
 313                 vuser->server_info->unix_name,
 314                 pdb_get_domain(vuser->server_info->sam_account));
 315
 316         return vuser->vuid;
 317
 318   fail:
 319
 320         if (vuser) {
 321                 invalidate_vuid(vuid);
 322         }
 323         return UID_FIELD_INVALID;
 324 }
 325
 326 /****************************************************************************
 327  Add a name to the session users list.
 328 ****************************************************************************/
 329
 330 void add_session_user(const char *user)
 331 {
 332         struct passwd *pw;
 333         char *tmp;
 334
 335         pw = Get_Pwnam_alloc(talloc_tos(), user);
 336
 337         if (pw == NULL) {
 338                 return;
 339         }
 340
 341         if (session_userlist == NULL) {
 342                 session_userlist = SMB_STRDUP(pw->pw_name);
 343                 goto done;
 344         }
 345
 346         if (in_list(pw->pw_name,session_userlist,False) ) {
 347                 goto done;
 348         }
 349
 350         if (strlen(session_userlist) > 128 * 1024) {
 351                 DEBUG(3,("add_session_user: session userlist already "
 352                          "too large.\n"));
 353                 goto done;
 354         }
 355
 356         if (asprintf(&tmp, "%s %s", session_userlist, pw->pw_name) == -1) {
 357                 DEBUG(3, ("asprintf failed\n"));
 358                 goto done;
 359         }
 360
 361         SAFE_FREE(session_userlist);
 362         session_userlist = tmp;
 363  done:
 364         TALLOC_FREE(pw);
 365 }
 366
 367 /****************************************************************************
 368  In security=share mode we need to store the client workgroup, as that's
 369   what Vista uses for the NTLMv2 calculation.
 370 ****************************************************************************/
 371
 372 void add_session_workgroup(const char *workgroup)
 373 {
 374         if (session_workgroup) {
 375                 SAFE_FREE(session_workgroup);
 376         }
 377         session_workgroup = smb_xstrdup(workgroup);
 378 }
 379
 380 /****************************************************************************
 381  In security=share mode we need to return the client workgroup, as that's
 382   what Vista uses for the NTLMv2 calculation.
 383 ****************************************************************************/
 384
 385 const char *get_session_workgroup(void)
 386 {
 387         return session_workgroup;
 388 }
 389
 390 /****************************************************************************
 391  Check if a user is in a netgroup user list. If at first we don't succeed,
 392  try lower case.
 393 ****************************************************************************/
 394
 395 bool user_in_netgroup(const char *user, const char *ngname)
 396 {
 397 #ifdef HAVE_NETGROUP
 398         fstring lowercase_user;
 399
 400         if (my_yp_domain == NULL)
 401                 yp_get_default_domain(&my_yp_domain);
 402
 403         if(my_yp_domain == NULL) {
 404                 DEBUG(5,("Unable to get default yp domain, "
 405                         "let's try without specifying it\n"));
 406         }
 407
 408         DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
 409                 user, my_yp_domain?my_yp_domain:"(ANY)", ngname));
 410
 411         if (innetgr(ngname, NULL, user, my_yp_domain)) {
 412                 DEBUG(5,("user_in_netgroup: Found\n"));
 413                 return (True);
 414         } else {
 415
 416                 /*
 417                  * Ok, innetgr is case sensitive. Try once more with lowercase
 418                  * just in case. Attempt to fix #703. JRA.
 419                  */
 420
 421                 fstrcpy(lowercase_user, user);
 422                 strlower_m(lowercase_user);
 423
 424                 DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
 425                         lowercase_user, my_yp_domain?my_yp_domain:"(ANY)", ngname));
 426
 427                 if (innetgr(ngname, NULL, lowercase_user, my_yp_domain)) {
 428                         DEBUG(5,("user_in_netgroup: Found\n"));
 429                         return (True);
 430                 }
 431         }
 432 #endif /* HAVE_NETGROUP */
 433         return False;
 434 }
 435
 436 /****************************************************************************
 437  Check if a user is in a user list - can check combinations of UNIX
 438  and netgroup lists.
 439 ****************************************************************************/
 440
 441 bool user_in_list(const char *user,const char **list)
 442 {
 443         if (!list || !*list)
 444                 return False;
 445
 446         DEBUG(10,("user_in_list: checking user %s in list\n", user));
 447
 448         while (*list) {
 449
 450                 DEBUG(10,("user_in_list: checking user |%s| against |%s|\n",
 451                           user, *list));
 452
 453                 /*
 454                  * Check raw username.
 455                  */
 456                 if (strequal(user, *list))
 457                         return(True);
 458
 459                 /*
 460                  * Now check to see if any combination
 461                  * of UNIX and netgroups has been specified.
 462                  */
 463
 464                 if(**list == '@') {
 465                         /*
 466                          * Old behaviour. Check netgroup list
 467                          * followed by UNIX list.
 468                          */
 469                         if(user_in_netgroup(user, *list +1))
 470                                 return True;
 471                         if(user_in_group(user, *list +1))
 472                                 return True;
 473                 } else if (**list == '+') {
 474
 475                         if((*(*list +1)) == '&') {
 476                                 /*
 477                                  * Search UNIX list followed by netgroup.
 478                                  */
 479                                 if(user_in_group(user, *list +2))
 480                                         return True;
 481                                 if(user_in_netgroup(user, *list +2))
 482                                         return True;
 483
 484                         } else {
 485
 486                                 /*
 487                                  * Just search UNIX list.
 488                                  */
 489
 490                                 if(user_in_group(user, *list +1))
 491                                         return True;
 492                         }
 493
 494                 } else if (**list == '&') {
 495
 496                         if(*(*list +1) == '+') {
 497                                 /*
 498                                  * Search netgroup list followed by UNIX list.
 499                                  */
 500                                 if(user_in_netgroup(user, *list +2))
 501                                         return True;
 502                                 if(user_in_group(user, *list +2))
 503                                         return True;
 504                         } else {
 505                                 /*
 506                                  * Just search netgroup list.
 507                                  */
 508                                 if(user_in_netgroup(user, *list +1))
 509                                         return True;
 510                         }
 511                 }
 512
 513                 list++;
 514         }
 515         return(False);
 516 }
 517
 518 /****************************************************************************
 519  Check if a username is valid.
 520 ****************************************************************************/
 521
 522 static bool user_ok(const char *user, int snum)
 523 {
 524         char **valid, **invalid;
 525         bool ret;
 526
 527         valid = invalid = NULL;
 528         ret = True;
 529
 530         if (lp_invalid_users(snum)) {
 531                 invalid = str_list_copy(talloc_tos(), lp_invalid_users(snum));
 532                 if (invalid &&
 533                     str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 534
 535                         /* This is used in sec=share only, so no current user
 536                          * around to pass to str_list_sub_basic() */
 537
 538                         if ( invalid && str_list_sub_basic(invalid, "", "") ) {
 539                                 ret = !user_in_list(user,
 540                                                     (const char **)invalid);
 541                         }
 542                 }
 543         }
 544         TALLOC_FREE(invalid);
 545
 546         if (ret && lp_valid_users(snum)) {
 547                 valid = str_list_copy(talloc_tos(), lp_valid_users(snum));
 548                 if ( valid &&
 549                      str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 550
 551                         /* This is used in sec=share only, so no current user
 552                          * around to pass to str_list_sub_basic() */
 553
 554                         if ( valid && str_list_sub_basic(valid, "", "") ) {
 555                                 ret = user_in_list(user, (const char **)valid);
 556                         }
 557                 }
 558         }
 559         TALLOC_FREE(valid);
 560
 561         if (ret && lp_onlyuser(snum)) {
 562                 char **user_list = str_list_make_v3(
 563                         talloc_tos(), lp_username(snum), NULL);
 564                 if (user_list &&
 565                     str_list_substitute(user_list, "%S",
 566                                         lp_servicename(snum))) {
 567                         ret = user_in_list(user, (const char **)user_list);
 568                 }
 569                 TALLOC_FREE(user_list);
 570         }
 571
 572         return(ret);
 573 }
 574
 575 /****************************************************************************
 576  Validate a group username entry. Return the username or NULL.
 577 ****************************************************************************/
 578
 579 static char *validate_group(char *group, DATA_BLOB password,int snum)
 580 {
 581 #ifdef HAVE_NETGROUP
 582         {
 583                 char *host, *user, *domain;
 584                 setnetgrent(group);
 585                 while (getnetgrent(&host, &user, &domain)) {
 586                         if (user) {
 587                                 if (user_ok(user, snum) &&
 588                                     password_ok(user,password)) {
 589                                         endnetgrent();
 590                                         return(user);
 591                                 }
 592                         }
 593                 }
 594                 endnetgrent();
 595         }
 596 #endif
 597
 598 #ifdef HAVE_GETGRENT
 599         {
 600                 struct group *gptr;
 601                 setgrent();
 602                 while ((gptr = (struct group *)getgrent())) {
 603                         if (strequal(gptr->gr_name,group))
 604                                 break;
 605                 }
 606
 607                 /*
 608                  * As user_ok can recurse doing a getgrent(), we must
 609                  * copy the member list onto the heap before
 610                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 611                  */
 612
 613                 if (gptr) {
 614                         char *member_list = NULL;
 615                         size_t list_len = 0;
 616                         char *member;
 617                         int i;
 618
 619                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 620                                 list_len += strlen(gptr->gr_mem[i])+1;
 621                         }
 622                         list_len++;
 623
 624                         member_list = (char *)SMB_MALLOC(list_len);
 625                         if (!member_list) {
 626                                 endgrent();
 627                                 return NULL;
 628                         }
 629
 630                         *member_list = '\0';
 631                         member = member_list;
 632
 633                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 634                                 size_t member_len = strlen(gptr->gr_mem[i])+1;
 635
 636                                 DEBUG(10,("validate_group: = gr_mem = "
 637                                           "%s\n", gptr->gr_mem[i]));
 638
 639                                 safe_strcpy(member, gptr->gr_mem[i],
 640                                         list_len - (member-member_list));
 641                                 member += member_len;
 642                         }
 643
 644                         endgrent();
 645
 646                         member = member_list;
 647                         while (*member) {
 648                                 if (user_ok(member,snum) &&
 649                                     password_ok(member,password)) {
 650                                         char *name = talloc_strdup(talloc_tos(),
 651                                                                 member);
 652                                         SAFE_FREE(member_list);
 653                                         return name;
 654                                 }
 655
 656                                 DEBUG(10,("validate_group = member = %s\n",
 657                                           member));
 658
 659                                 member += strlen(member) + 1;
 660                         }
 661
 662                         SAFE_FREE(member_list);
 663                 } else {
 664                         endgrent();
 665                         return NULL;
 666                 }
 667         }
 668 #endif
 669         return(NULL);
 670 }
 671
 672 /****************************************************************************
 673  Check for authority to login to a service with a given username/password.
 674  Note this is *NOT* used when logging on using sessionsetup_and_X.
 675 ****************************************************************************/
 676
 677 bool authorise_login(int snum, fstring user, DATA_BLOB password,
 678                      bool *guest)
 679 {
 680         bool ok = False;
 681
 682 #ifdef DEBUG_PASSWORD
 683         DEBUG(100,("authorise_login: checking authorisation on "
 684                    "user=%s pass=%s\n", user,password.data));
 685 #endif
 686
 687         *guest = False;
 688
 689         /* there are several possibilities:
 690                 1) login as the given user with given password
 691                 2) login as a previously registered username with the given
 692                    password
 693                 3) login as a session list username with the given password
 694                 4) login as a previously validated user/password pair
 695                 5) login as the "user =" user with given password
 696                 6) login as the "user =" user with no password
 697                    (guest connection)
 698                 7) login as guest user with no password
 699
 700                 if the service is guest_only then steps 1 to 5 are skipped
 701         */
 702
 703         /* now check the list of session users */
 704         if (!ok) {
 705                 char *auser;
 706                 char *user_list = NULL;
 707                 char *saveptr;
 708
 709                 if ( session_userlist )
 710                         user_list = SMB_STRDUP(session_userlist);
 711                 else
 712                         user_list = SMB_STRDUP("");
 713
 714                 if (!user_list)
 715                         return(False);
 716
 717                 for (auser = strtok_r(user_list, LIST_SEP, &saveptr);
 718                      !ok && auser;
 719                      auser = strtok_r(NULL, LIST_SEP, &saveptr)) {
 720                         fstring user2;
 721                         fstrcpy(user2,auser);
 722                         if (!user_ok(user2,snum))
 723                                 continue;
 724
 725                         if (password_ok(user2,password)) {
 726                                 ok = True;
 727                                 fstrcpy(user,user2);
 728                                 DEBUG(3,("authorise_login: ACCEPTED: session "
 729                                          "list username (%s) and given "
 730                                          "password ok\n", user));
 731                         }
 732                 }
 733
 734                 SAFE_FREE(user_list);
 735         }
 736
 737         /* check the user= fields and the given password */
 738         if (!ok && lp_username(snum)) {
 739                 TALLOC_CTX *ctx = talloc_tos();
 740                 char *auser;
 741                 char *user_list = talloc_strdup(ctx, lp_username(snum));
 742                 char *saveptr;
 743
 744                 if (!user_list) {
 745                         goto check_guest;
 746                 }
 747
 748                 user_list = talloc_string_sub(ctx,
 749                                 user_list,
 750                                 "%S",
 751                                 lp_servicename(snum));
 752
 753                 if (!user_list) {
 754                         goto check_guest;
 755                 }
 756
 757                 for (auser = strtok_r(user_list, LIST_SEP, &saveptr);
 758                      auser && !ok;
 759                      auser = strtok_r(NULL, LIST_SEP, &saveptr)) {
 760                         if (*auser == '@') {
 761                                 auser = validate_group(auser+1,password,snum);
 762                                 if (auser) {
 763                                         ok = True;
 764                                         fstrcpy(user,auser);
 765                                         DEBUG(3,("authorise_login: ACCEPTED: "
 766                                                  "group username and given "
 767                                                  "password ok (%s)\n", user));
 768                                 }
 769                         } else {
 770                                 fstring user2;
 771                                 fstrcpy(user2,auser);
 772                                 if (user_ok(user2,snum) &&
 773                                     password_ok(user2,password)) {
 774                                         ok = True;
 775                                         fstrcpy(user,user2);
 776                                         DEBUG(3,("authorise_login: ACCEPTED: "
 777                                                  "user list username and "
 778                                                  "given password ok (%s)\n",
 779                                                  user));
 780                                 }
 781                         }
 782                 }
 783         }
 784
 785   check_guest:
 786
 787         /* check for a normal guest connection */
 788         if (!ok && GUEST_OK(snum)) {
 789                 struct passwd *guest_pw;
 790                 fstring guestname;
 791                 fstrcpy(guestname,lp_guestaccount());
 792                 guest_pw = Get_Pwnam_alloc(talloc_tos(), guestname);
 793                 if (guest_pw != NULL) {
 794                         fstrcpy(user,guestname);
 795                         ok = True;
 796                         DEBUG(3,("authorise_login: ACCEPTED: guest account "
 797                                  "and guest ok (%s)\n", user));
 798                 } else {
 799                         DEBUG(0,("authorise_login: Invalid guest account "
 800                                  "%s??\n",guestname));
 801                 }
 802                 TALLOC_FREE(guest_pw);
 803                 *guest = True;
 804         }
 805
 806         if (ok && !user_ok(user, snum)) {
 807                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 808                 ok = False;
 809         }
 810
 811         return(ok);
 812 }