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
  23 /* users from session setup */
  24 static char *session_userlist = NULL;
  25 /* workgroup from session setup. */
  26 static char *session_workgroup = NULL;
  27
  28 /* this holds info on user ids that are already validated for this VC */
  29 static user_struct *validated_users;
  30 static int next_vuid = VUID_OFFSET;
  31 static int num_validated_vuids;
  32
  33 enum server_allocated_state { SERVER_ALLOCATED_REQUIRED_YES,
  34                                 SERVER_ALLOCATED_REQUIRED_NO,
  35                                 SERVER_ALLOCATED_REQUIRED_ANY};
  36
  37 static user_struct *get_valid_user_struct_internal(uint16 vuid,
  38                         enum server_allocated_state server_allocated)
  39 {
  40         user_struct *usp;
  41         int count=0;
  42
  43         if (vuid == UID_FIELD_INVALID)
  44                 return NULL;
  45
  46         for (usp=validated_users;usp;usp=usp->next,count++) {
  47                 if (vuid == usp->vuid) {
  48                         switch (server_allocated) {
  49                                 case SERVER_ALLOCATED_REQUIRED_YES:
  50                                         if (usp->server_info == NULL) {
  51                                                 continue;
  52                                         }
  53                                         break;
  54                                 case SERVER_ALLOCATED_REQUIRED_NO:
  55                                         if (usp->server_info != NULL) {
  56                                                 continue;
  57                                         }
  58                                 case SERVER_ALLOCATED_REQUIRED_ANY:
  59                                         break;
  60                         }
  61                         if (count > 10) {
  62                                 DLIST_PROMOTE(validated_users, usp);
  63                         }
  64                         return usp;
  65                 }
  66         }
  67
  68         return NULL;
  69 }
  70
  71 /****************************************************************************
  72  Check if a uid has been validated, and return an pointer to the user_struct
  73  if it has. NULL if not. vuid is biased by an offset. This allows us to
  74  tell random client vuid's (normally zero) from valid vuids.
  75 ****************************************************************************/
  76
  77 user_struct *get_valid_user_struct(uint16 vuid)
  78 {
  79         return get_valid_user_struct_internal(vuid,
  80                         SERVER_ALLOCATED_REQUIRED_YES);
  81 }
  82
  83 bool is_partial_auth_vuid(uint16 vuid)
  84 {
  85         if (vuid == UID_FIELD_INVALID) {
  86                 return False;
  87         }
  88         return get_valid_user_struct_internal(vuid,
  89                         SERVER_ALLOCATED_REQUIRED_NO) ? True : False;
  90 }
  91
  92 /****************************************************************************
  93  Get the user struct of a partial NTLMSSP login
  94 ****************************************************************************/
  95
  96 user_struct *get_partial_auth_user_struct(uint16 vuid)
  97 {
  98         return get_valid_user_struct_internal(vuid,
  99                         SERVER_ALLOCATED_REQUIRED_NO);
 100 }
 101
 102 /****************************************************************************
 103  Invalidate a uid.
 104 ****************************************************************************/
 105
 106 void invalidate_vuid(uint16 vuid)
 107 {
 108         user_struct *vuser = NULL;
 109
 110         if (vuid == UID_FIELD_INVALID) {
 111                 return;
 112         }
 113
 114         vuser = get_valid_user_struct_internal(vuid,
 115                         SERVER_ALLOCATED_REQUIRED_ANY);
 116         if (vuser == NULL) {
 117                 return;
 118         }
 119
 120         session_yield(vuser);
 121
 122         data_blob_free(&vuser->session_key);
 123
 124         if (vuser->auth_ntlmssp_state) {
 125                 auth_ntlmssp_end(&vuser->auth_ntlmssp_state);
 126         }
 127
 128         DLIST_REMOVE(validated_users, vuser);
 129
 130         /* clear the vuid from the 'cache' on each connection, and
 131            from the vuid 'owner' of connections */
 132         conn_clear_vuid_cache(vuid);
 133
 134         TALLOC_FREE(vuser);
 135         num_validated_vuids--;
 136 }
 137
 138 /****************************************************************************
 139  Invalidate all vuid entries for this process.
 140 ****************************************************************************/
 141
 142 void invalidate_all_vuids(void)
 143 {
 144         user_struct *usp, *next=NULL;
 145
 146         for (usp=validated_users;usp;usp=next) {
 147                 next = usp->next;
 148                 invalidate_vuid(usp->vuid);
 149         }
 150 }
 151
 152 /****************************************************
 153  Create a new partial auth user struct.
 154 *****************************************************/
 155
 156 int register_initial_vuid(void)
 157 {
 158         user_struct *vuser;
 159
 160         /* Paranoia check. */
 161         if(lp_security() == SEC_SHARE) {
 162                 smb_panic("register_initial_vuid: "
 163                         "Tried to register uid in security=share");
 164         }
 165
 166         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 167         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 168                 return UID_FIELD_INVALID;
 169         }
 170
 171         if((vuser = talloc_zero(NULL, user_struct)) == NULL) {
 172                 DEBUG(0,("register_initial_vuid: "
 173                                 "Failed to talloc users struct!\n"));
 174                 return UID_FIELD_INVALID;
 175         }
 176
 177         /* Allocate a free vuid. Yes this is a linear search... */
 178         while( get_valid_user_struct_internal(next_vuid,
 179                         SERVER_ALLOCATED_REQUIRED_ANY) != NULL ) {
 180                 next_vuid++;
 181                 /* Check for vuid wrap. */
 182                 if (next_vuid == UID_FIELD_INVALID) {
 183                         next_vuid = VUID_OFFSET;
 184                 }
 185         }
 186
 187         DEBUG(10,("register_initial_vuid: allocated vuid = %u\n",
 188                 (unsigned int)next_vuid ));
 189
 190         vuser->vuid = next_vuid;
 191
 192         /*
 193          * This happens in an unfinished NTLMSSP session setup. We
 194          * need to allocate a vuid between the first and second calls
 195          * to NTLMSSP.
 196          */
 197         next_vuid++;
 198         num_validated_vuids++;
 199
 200         DLIST_ADD(validated_users, vuser);
 201         return vuser->vuid;
 202 }
 203
 204 static int register_homes_share(const char *username)
 205 {
 206         int result;
 207         struct passwd *pwd;
 208
 209         result = lp_servicenumber(username);
 210         if (result != -1) {
 211                 DEBUG(3, ("Using static (or previously created) service for "
 212                           "user '%s'; path = '%s'\n", username,
 213                           lp_pathname(result)));
 214                 return result;
 215         }
 216
 217         pwd = getpwnam_alloc(talloc_tos(), username);
 218
 219         if ((pwd == NULL) || (pwd->pw_dir[0] == '\0')) {
 220                 DEBUG(3, ("No home directory defined for user '%s'\n",
 221                           username));
 222                 TALLOC_FREE(pwd);
 223                 return -1;
 224         }
 225
 226         DEBUG(3, ("Adding homes service for user '%s' using home directory: "
 227                   "'%s'\n", username, pwd->pw_dir));
 228
 229         result = add_home_service(username, username, pwd->pw_dir);
 230
 231         TALLOC_FREE(pwd);
 232         return result;
 233 }
 234
 235 /**
 236  *  register that a valid login has been performed, establish 'session'.
 237  *  @param server_info The token returned from the authentication process.
 238  *   (now 'owned' by register_existing_vuid)
 239  *
 240  *  @param session_key The User session key for the login session (now also
 241  *  'owned' by register_existing_vuid)
 242  *
 243  *  @param respose_blob The NT challenge-response, if available.  (May be
 244  *  freed after this call)
 245  *
 246  *  @param smb_name The untranslated name of the user
 247  *
 248  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 249  *   tell random client vuid's (normally zero) from valid vuids.)
 250  *
 251  */
 252
 253 int register_existing_vuid(uint16 vuid,
 254                         auth_serversupplied_info *server_info,
 255                         DATA_BLOB session_key,
 256                         DATA_BLOB response_blob,
 257                         const char *smb_name)
 258 {
 259         user_struct *vuser = get_partial_auth_user_struct(vuid);
 260         if (!vuser) {
 261                 goto fail;
 262         }
 263
 264         /* Use this to keep tabs on all our info from the authentication */
 265         vuser->server_info = server_info;
 266
 267         /* Ensure that the server_info will disappear with
 268          * the vuser it is now attached to */
 269
 270         talloc_steal(vuser, vuser->server_info);
 271
 272         /* the next functions should be done by a SID mapping system (SMS) as
 273          * the new real sam db won't have reference to unix uids or gids
 274          */
 275
 276         vuser->uid = server_info->uid;
 277         vuser->gid = server_info->gid;
 278
 279         vuser->n_groups = server_info->n_groups;
 280         if (vuser->n_groups) {
 281                 if (!(vuser->groups = (gid_t *)talloc_memdup(vuser,
 282                                         server_info->groups,
 283                                         sizeof(gid_t)*vuser->n_groups))) {
 284                         DEBUG(0,("register_existing_vuid: "
 285                                 "failed to talloc_memdup vuser->groups\n"));
 286                         goto fail;
 287                 }
 288         }
 289
 290         vuser->guest = server_info->guest;
 291         fstrcpy(vuser->user.unix_name, server_info->unix_name);
 292
 293         /* This is a potentially untrusted username */
 294         alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$",
 295                 sizeof(vuser->user.smb_name));
 296
 297         fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
 298         fstrcpy(vuser->user.full_name,
 299         pdb_get_fullname(server_info->sam_account));
 300
 301         {
 302                 const char *logon_script =
 303                         pdb_get_logon_script(server_info->sam_account);
 304
 305                 if (logon_script) {
 306                         vuser->logon_script = logon_script;
 307                 }
 308         }
 309         vuser->session_key = session_key;
 310
 311         DEBUG(10,("register_existing_vuid: (%u,%u) %s %s %s guest=%d\n",
 312                         (unsigned int)vuser->uid,
 313                         (unsigned int)vuser->gid,
 314                         vuser->user.unix_name, vuser->user.smb_name,
 315                         vuser->user.domain, vuser->guest ));
 316
 317         DEBUG(3, ("register_existing_vuid: User name: %s\t"
 318                 "Real name: %s\n", vuser->user.unix_name,
 319                 vuser->user.full_name));
 320
 321         if (server_info->ptok) {
 322                 vuser->nt_user_token = dup_nt_token(vuser, server_info->ptok);
 323         } else {
 324                 DEBUG(1, ("register_existing_vuid: server_info does not "
 325                         "contain a user_token - cannot continue\n"));
 326                 goto fail;
 327         }
 328
 329         DEBUG(3,("register_existing_vuid: UNIX uid %d is UNIX user %s, "
 330                 "and will be vuid %u\n",
 331                 (int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 332
 333         next_vuid++;
 334         num_validated_vuids++;
 335
 336         if (!session_claim(vuser)) {
 337                 DEBUG(1, ("register_existing_vuid: Failed to claim session "
 338                         "for vuid=%d\n",
 339                         vuser->vuid));
 340                 goto fail;
 341         }
 342
 343         /* Register a home dir service for this user if
 344         (a) This is not a guest connection,
 345         (b) we have a home directory defined
 346         (c) there s not an existing static share by that name
 347         If a share exists by this name (autoloaded or not) reuse it . */
 348
 349         vuser->homes_snum = -1;
 350
 351         if (!vuser->guest) {
 352                 vuser->homes_snum = register_homes_share(
 353                         vuser->user.unix_name);
 354         }
 355
 356         if (srv_is_signing_negotiated() && !vuser->guest &&
 357                         !srv_signing_started()) {
 358                 /* Try and turn on server signing on the first non-guest
 359                  * sessionsetup. */
 360                 srv_set_signing(vuser->session_key, response_blob);
 361         }
 362
 363         /* fill in the current_user_info struct */
 364         set_current_user_info( &vuser->user );
 365         return vuser->vuid;
 366
 367   fail:
 368
 369         if (vuser) {
 370                 invalidate_vuid(vuid);
 371         }
 372         return UID_FIELD_INVALID;
 373 }
 374
 375 /****************************************************************************
 376  Add a name to the session users list.
 377 ****************************************************************************/
 378
 379 void add_session_user(const char *user)
 380 {
 381         struct passwd *pw;
 382         char *tmp;
 383
 384         pw = Get_Pwnam_alloc(talloc_tos(), user);
 385
 386         if (pw == NULL) {
 387                 return;
 388         }
 389
 390         if (session_userlist == NULL) {
 391                 session_userlist = SMB_STRDUP(pw->pw_name);
 392                 goto done;
 393         }
 394
 395         if (in_list(pw->pw_name,session_userlist,False) ) {
 396                 goto done;
 397         }
 398
 399         if (strlen(session_userlist) > 128 * 1024) {
 400                 DEBUG(3,("add_session_user: session userlist already "
 401                          "too large.\n"));
 402                 goto done;
 403         }
 404
 405         if (asprintf(&tmp, "%s %s", session_userlist, pw->pw_name) == -1) {
 406                 DEBUG(3, ("asprintf failed\n"));
 407                 goto done;
 408         }
 409
 410         SAFE_FREE(session_userlist);
 411         session_userlist = tmp;
 412  done:
 413         TALLOC_FREE(pw);
 414 }
 415
 416 /****************************************************************************
 417  In security=share mode we need to store the client workgroup, as that's
 418   what Vista uses for the NTLMv2 calculation.
 419 ****************************************************************************/
 420
 421 void add_session_workgroup(const char *workgroup)
 422 {
 423         if (session_workgroup) {
 424                 SAFE_FREE(session_workgroup);
 425         }
 426         session_workgroup = smb_xstrdup(workgroup);
 427 }
 428
 429 /****************************************************************************
 430  In security=share mode we need to return the client workgroup, as that's
 431   what Vista uses for the NTLMv2 calculation.
 432 ****************************************************************************/
 433
 434 const char *get_session_workgroup(void)
 435 {
 436         return session_workgroup;
 437 }
 438
 439 /****************************************************************************
 440  Check if a user is in a netgroup user list. If at first we don't succeed,
 441  try lower case.
 442 ****************************************************************************/
 443
 444 bool user_in_netgroup(const char *user, const char *ngname)
 445 {
 446 #ifdef HAVE_NETGROUP
 447         static char *mydomain = NULL;
 448         fstring lowercase_user;
 449
 450         if (mydomain == NULL)
 451                 yp_get_default_domain(&mydomain);
 452
 453         if(mydomain == NULL) {
 454                 DEBUG(5,("Unable to get default yp domain, "
 455                         "let's try without specifying it\n"));
 456         }
 457
 458         DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
 459                 user, mydomain?mydomain:"(ANY)", ngname));
 460
 461         if (innetgr(ngname, NULL, user, mydomain)) {
 462                 DEBUG(5,("user_in_netgroup: Found\n"));
 463                 return (True);
 464         } else {
 465
 466                 /*
 467                  * Ok, innetgr is case sensitive. Try once more with lowercase
 468                  * just in case. Attempt to fix #703. JRA.
 469                  */
 470
 471                 fstrcpy(lowercase_user, user);
 472                 strlower_m(lowercase_user);
 473
 474                 DEBUG(5,("looking for user %s of domain %s in netgroup %s\n",
 475                         lowercase_user, mydomain?mydomain:"(ANY)", ngname));
 476
 477                 if (innetgr(ngname, NULL, lowercase_user, mydomain)) {
 478                         DEBUG(5,("user_in_netgroup: Found\n"));
 479                         return (True);
 480                 }
 481         }
 482 #endif /* HAVE_NETGROUP */
 483         return False;
 484 }
 485
 486 /****************************************************************************
 487  Check if a user is in a user list - can check combinations of UNIX
 488  and netgroup lists.
 489 ****************************************************************************/
 490
 491 bool user_in_list(const char *user,const char **list)
 492 {
 493         if (!list || !*list)
 494                 return False;
 495
 496         DEBUG(10,("user_in_list: checking user %s in list\n", user));
 497
 498         while (*list) {
 499
 500                 DEBUG(10,("user_in_list: checking user |%s| against |%s|\n",
 501                           user, *list));
 502
 503                 /*
 504                  * Check raw username.
 505                  */
 506                 if (strequal(user, *list))
 507                         return(True);
 508
 509                 /*
 510                  * Now check to see if any combination
 511                  * of UNIX and netgroups has been specified.
 512                  */
 513
 514                 if(**list == '@') {
 515                         /*
 516                          * Old behaviour. Check netgroup list
 517                          * followed by UNIX list.
 518                          */
 519                         if(user_in_netgroup(user, *list +1))
 520                                 return True;
 521                         if(user_in_group(user, *list +1))
 522                                 return True;
 523                 } else if (**list == '+') {
 524
 525                         if((*(*list +1)) == '&') {
 526                                 /*
 527                                  * Search UNIX list followed by netgroup.
 528                                  */
 529                                 if(user_in_group(user, *list +2))
 530                                         return True;
 531                                 if(user_in_netgroup(user, *list +2))
 532                                         return True;
 533
 534                         } else {
 535
 536                                 /*
 537                                  * Just search UNIX list.
 538                                  */
 539
 540                                 if(user_in_group(user, *list +1))
 541                                         return True;
 542                         }
 543
 544                 } else if (**list == '&') {
 545
 546                         if(*(*list +1) == '+') {
 547                                 /*
 548                                  * Search netgroup list followed by UNIX list.
 549                                  */
 550                                 if(user_in_netgroup(user, *list +2))
 551                                         return True;
 552                                 if(user_in_group(user, *list +2))
 553                                         return True;
 554                         } else {
 555                                 /*
 556                                  * Just search netgroup list.
 557                                  */
 558                                 if(user_in_netgroup(user, *list +1))
 559                                         return True;
 560                         }
 561                 }
 562
 563                 list++;
 564         }
 565         return(False);
 566 }
 567
 568 /****************************************************************************
 569  Check if a username is valid.
 570 ****************************************************************************/
 571
 572 static bool user_ok(const char *user, int snum)
 573 {
 574         char **valid, **invalid;
 575         bool ret;
 576
 577         valid = invalid = NULL;
 578         ret = True;
 579
 580         if (lp_invalid_users(snum)) {
 581                 str_list_copy(talloc_tos(), &invalid, lp_invalid_users(snum));
 582                 if (invalid &&
 583                     str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 584
 585                         /* This is used in sec=share only, so no current user
 586                          * around to pass to str_list_sub_basic() */
 587
 588                         if ( invalid && str_list_sub_basic(invalid, "", "") ) {
 589                                 ret = !user_in_list(user,
 590                                                     (const char **)invalid);
 591                         }
 592                 }
 593         }
 594         TALLOC_FREE(invalid);
 595
 596         if (ret && lp_valid_users(snum)) {
 597                 str_list_copy(talloc_tos(), &valid, lp_valid_users(snum));
 598                 if ( valid &&
 599                      str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 600
 601                         /* This is used in sec=share only, so no current user
 602                          * around to pass to str_list_sub_basic() */
 603
 604                         if ( valid && str_list_sub_basic(valid, "", "") ) {
 605                                 ret = user_in_list(user, (const char **)valid);
 606                         }
 607                 }
 608         }
 609         TALLOC_FREE(valid);
 610
 611         if (ret && lp_onlyuser(snum)) {
 612                 char **user_list = str_list_make(
 613                         talloc_tos(), lp_username(snum), NULL);
 614                 if (user_list &&
 615                     str_list_substitute(user_list, "%S",
 616                                         lp_servicename(snum))) {
 617                         ret = user_in_list(user, (const char **)user_list);
 618                 }
 619                 TALLOC_FREE(user_list);
 620         }
 621
 622         return(ret);
 623 }
 624
 625 /****************************************************************************
 626  Validate a group username entry. Return the username or NULL.
 627 ****************************************************************************/
 628
 629 static char *validate_group(char *group, DATA_BLOB password,int snum)
 630 {
 631 #ifdef HAVE_NETGROUP
 632         {
 633                 char *host, *user, *domain;
 634                 setnetgrent(group);
 635                 while (getnetgrent(&host, &user, &domain)) {
 636                         if (user) {
 637                                 if (user_ok(user, snum) &&
 638                                     password_ok(user,password)) {
 639                                         endnetgrent();
 640                                         return(user);
 641                                 }
 642                         }
 643                 }
 644                 endnetgrent();
 645         }
 646 #endif
 647
 648 #ifdef HAVE_GETGRENT
 649         {
 650                 struct group *gptr;
 651                 setgrent();
 652                 while ((gptr = (struct group *)getgrent())) {
 653                         if (strequal(gptr->gr_name,group))
 654                                 break;
 655                 }
 656
 657                 /*
 658                  * As user_ok can recurse doing a getgrent(), we must
 659                  * copy the member list onto the heap before
 660                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 661                  */
 662
 663                 if (gptr) {
 664                         char *member_list = NULL;
 665                         size_t list_len = 0;
 666                         char *member;
 667                         int i;
 668
 669                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 670                                 list_len += strlen(gptr->gr_mem[i])+1;
 671                         }
 672                         list_len++;
 673
 674                         member_list = (char *)SMB_MALLOC(list_len);
 675                         if (!member_list) {
 676                                 endgrent();
 677                                 return NULL;
 678                         }
 679
 680                         *member_list = '\0';
 681                         member = member_list;
 682
 683                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 684                                 size_t member_len = strlen(gptr->gr_mem[i])+1;
 685
 686                                 DEBUG(10,("validate_group: = gr_mem = "
 687                                           "%s\n", gptr->gr_mem[i]));
 688
 689                                 safe_strcpy(member, gptr->gr_mem[i],
 690                                         list_len - (member-member_list));
 691                                 member += member_len;
 692                         }
 693
 694                         endgrent();
 695
 696                         member = member_list;
 697                         while (*member) {
 698                                 if (user_ok(member,snum) &&
 699                                     password_ok(member,password)) {
 700                                         char *name = talloc_strdup(talloc_tos(),
 701                                                                 member);
 702                                         SAFE_FREE(member_list);
 703                                         return name;
 704                                 }
 705
 706                                 DEBUG(10,("validate_group = member = %s\n",
 707                                           member));
 708
 709                                 member += strlen(member) + 1;
 710                         }
 711
 712                         SAFE_FREE(member_list);
 713                 } else {
 714                         endgrent();
 715                         return NULL;
 716                 }
 717         }
 718 #endif
 719         return(NULL);
 720 }
 721
 722 /****************************************************************************
 723  Check for authority to login to a service with a given username/password.
 724  Note this is *NOT* used when logging on using sessionsetup_and_X.
 725 ****************************************************************************/
 726
 727 bool authorise_login(int snum, fstring user, DATA_BLOB password,
 728                      bool *guest)
 729 {
 730         bool ok = False;
 731
 732 #ifdef DEBUG_PASSWORD
 733         DEBUG(100,("authorise_login: checking authorisation on "
 734                    "user=%s pass=%s\n", user,password.data));
 735 #endif
 736
 737         *guest = False;
 738
 739         /* there are several possibilities:
 740                 1) login as the given user with given password
 741                 2) login as a previously registered username with the given
 742                    password
 743                 3) login as a session list username with the given password
 744                 4) login as a previously validated user/password pair
 745                 5) login as the "user =" user with given password
 746                 6) login as the "user =" user with no password
 747                    (guest connection)
 748                 7) login as guest user with no password
 749
 750                 if the service is guest_only then steps 1 to 5 are skipped
 751         */
 752
 753         /* now check the list of session users */
 754         if (!ok) {
 755                 char *auser;
 756                 char *user_list = NULL;
 757                 char *saveptr;
 758
 759                 if ( session_userlist )
 760                         user_list = SMB_STRDUP(session_userlist);
 761                 else
 762                         user_list = SMB_STRDUP("");
 763
 764                 if (!user_list)
 765                         return(False);
 766
 767                 for (auser = strtok_r(user_list, LIST_SEP, &saveptr);
 768                      !ok && auser;
 769                      auser = strtok_r(NULL, LIST_SEP, &saveptr)) {
 770                         fstring user2;
 771                         fstrcpy(user2,auser);
 772                         if (!user_ok(user2,snum))
 773                                 continue;
 774
 775                         if (password_ok(user2,password)) {
 776                                 ok = True;
 777                                 fstrcpy(user,user2);
 778                                 DEBUG(3,("authorise_login: ACCEPTED: session "
 779                                          "list username (%s) and given "
 780                                          "password ok\n", user));
 781                         }
 782                 }
 783
 784                 SAFE_FREE(user_list);
 785         }
 786
 787         /* check the user= fields and the given password */
 788         if (!ok && lp_username(snum)) {
 789                 TALLOC_CTX *ctx = talloc_tos();
 790                 char *auser;
 791                 char *user_list = talloc_strdup(ctx, lp_username(snum));
 792                 char *saveptr;
 793
 794                 if (!user_list) {
 795                         goto check_guest;
 796                 }
 797
 798                 user_list = talloc_string_sub(ctx,
 799                                 user_list,
 800                                 "%S",
 801                                 lp_servicename(snum));
 802
 803                 if (!user_list) {
 804                         goto check_guest;
 805                 }
 806
 807                 for (auser = strtok_r(user_list, LIST_SEP, &saveptr);
 808                      auser && !ok;
 809                      auser = strtok_r(NULL, LIST_SEP, &saveptr)) {
 810                         if (*auser == '@') {
 811                                 auser = validate_group(auser+1,password,snum);
 812                                 if (auser) {
 813                                         ok = True;
 814                                         fstrcpy(user,auser);
 815                                         DEBUG(3,("authorise_login: ACCEPTED: "
 816                                                  "group username and given "
 817                                                  "password ok (%s)\n", user));
 818                                 }
 819                         } else {
 820                                 fstring user2;
 821                                 fstrcpy(user2,auser);
 822                                 if (user_ok(user2,snum) &&
 823                                     password_ok(user2,password)) {
 824                                         ok = True;
 825                                         fstrcpy(user,user2);
 826                                         DEBUG(3,("authorise_login: ACCEPTED: "
 827                                                  "user list username and "
 828                                                  "given password ok (%s)\n",
 829                                                  user));
 830                                 }
 831                         }
 832                 }
 833         }
 834
 835   check_guest:
 836
 837         /* check for a normal guest connection */
 838         if (!ok && GUEST_OK(snum)) {
 839                 struct passwd *guest_pw;
 840                 fstring guestname;
 841                 fstrcpy(guestname,lp_guestaccount());
 842                 guest_pw = Get_Pwnam_alloc(talloc_tos(), guestname);
 843                 if (guest_pw != NULL) {
 844                         fstrcpy(user,guestname);
 845                         ok = True;
 846                         DEBUG(3,("authorise_login: ACCEPTED: guest account "
 847                                  "and guest ok (%s)\n", user));
 848                 } else {
 849                         DEBUG(0,("authorise_login: Invalid guest account "
 850                                  "%s??\n",guestname));
 851                 }
 852                 TALLOC_FREE(guest_pw);
 853                 *guest = True;
 854         }
 855
 856         if (ok && !user_ok(user, snum)) {
 857                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 858                 ok = False;
 859         }
 860
 861         return(ok);
 862 }