source3/smbd/password.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Password and authentication handling
   4    Copyright (C) Andrew Tridgell 1992-1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 #include "includes.h"
  22
  23 /* users from session setup */
  24 static char *session_userlist = NULL;
  25 static int len_session_userlist = 0;
  26
  27 /* this holds info on user ids that are already validated for this VC */
  28 static user_struct *validated_users;
  29 static int next_vuid = VUID_OFFSET;
  30 static int num_validated_vuids;
  31
  32 extern userdom_struct current_user_info;
  33
  34
  35 /****************************************************************************
  36  Check if a uid has been validated, and return an pointer to the user_struct
  37  if it has. NULL if not. vuid is biased by an offset. This allows us to
  38  tell random client vuid's (normally zero) from valid vuids.
  39 ****************************************************************************/
  40
  41 user_struct *get_valid_user_struct(uint16 vuid)
  42 {
  43         user_struct *usp;
  44         int count=0;
  45
  46         if (vuid == UID_FIELD_INVALID)
  47                 return NULL;
  48
  49         for (usp=validated_users;usp;usp=usp->next,count++) {
  50                 if (vuid == usp->vuid && usp->server_info) {
  51                         if (count > 10) {
  52                                 DLIST_PROMOTE(validated_users, usp);
  53                         }
  54                         return usp;
  55                 }
  56         }
  57
  58         return NULL;
  59 }
  60
  61 /****************************************************************************
  62  Get the user struct of a partial NTLMSSP login
  63 ****************************************************************************/
  64
  65 user_struct *get_partial_auth_user_struct(uint16 vuid)
  66 {
  67         user_struct *usp;
  68         int count=0;
  69
  70         if (vuid == UID_FIELD_INVALID)
  71                 return NULL;
  72
  73         for (usp=validated_users;usp;usp=usp->next,count++) {
  74                 if (vuid == usp->vuid && !usp->server_info) {
  75                         if (count > 10) {
  76                                 DLIST_PROMOTE(validated_users, usp);
  77                         }
  78                         return usp;
  79                 }
  80         }
  81
  82         return NULL;
  83 }
  84
  85 /****************************************************************************
  86  Invalidate a uid.
  87 ****************************************************************************/
  88
  89 void invalidate_vuid(uint16 vuid)
  90 {
  91         user_struct *vuser = get_valid_user_struct(vuid);
  92
  93         if (vuser == NULL)
  94                 return;
  95
  96         SAFE_FREE(vuser->homedir);
  97         SAFE_FREE(vuser->unix_homedir);
  98         SAFE_FREE(vuser->logon_script);
  99
 100         session_yield(vuser);
 101         SAFE_FREE(vuser->session_keystr);
 102
 103         talloc_free(vuser->server_info);
 104
 105         data_blob_free(&vuser->session_key);
 106
 107         DLIST_REMOVE(validated_users, vuser);
 108
 109         /* clear the vuid from the 'cache' on each connection, and
 110            from the vuid 'owner' of connections */
 111         conn_clear_vuid_cache(vuid);
 112
 113         SAFE_FREE(vuser->groups);
 114         talloc_free(vuser->nt_user_token);
 115         SAFE_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         user_struct *usp, *next=NULL;
 126
 127         for (usp=validated_users;usp;usp=next) {
 128                 next = usp->next;
 129
 130                 invalidate_vuid(usp->vuid);
 131         }
 132 }
 133
 134 /**
 135  *  register that a valid login has been performed, establish 'session'.
 136  *  @param server_info The token returned from the authentication process.
 137  *   (now 'owned' by register_vuid)
 138  *
 139  *  @param session_key The User session key for the login session (now also
 140  *  'owned' by register_vuid)
 141  *
 142  *  @param respose_blob The NT challenge-response, if available.  (May be
 143  *  freed after this call)
 144  *
 145  *  @param smb_name The untranslated name of the user
 146  *
 147  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 148  *   tell random client vuid's (normally zero) from valid vuids.)
 149  *
 150  */
 151
 152 int register_vuid(auth_serversupplied_info *server_info,
 153                   DATA_BLOB session_key, DATA_BLOB response_blob,
 154                   const char *smb_name)
 155 {
 156         user_struct *vuser = NULL;
 157
 158         /* Ensure no vuid gets registered in share level security. */
 159         if(lp_security() == SEC_SHARE) {
 160                 data_blob_free(&session_key);
 161                 return UID_FIELD_INVALID;
 162         }
 163
 164         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 165         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 166                 data_blob_free(&session_key);
 167                 return UID_FIELD_INVALID;
 168         }
 169
 170         if((vuser = SMB_MALLOC_P(user_struct)) == NULL) {
 171                 DEBUG(0,("Failed to malloc users struct!\n"));
 172                 data_blob_free(&session_key);
 173                 return UID_FIELD_INVALID;
 174         }
 175
 176         ZERO_STRUCTP(vuser);
 177
 178         /* Allocate a free vuid. Yes this is a linear search... :-) */
 179         while( get_valid_user_struct(next_vuid) != NULL ) {
 180                 next_vuid++;
 181                 /* Check for vuid wrap. */
 182                 if (next_vuid == UID_FIELD_INVALID)
 183                         next_vuid = VUID_OFFSET;
 184         }
 185
 186         DEBUG(10,("register_vuid: allocated vuid = %u\n",
 187                   (unsigned int)next_vuid ));
 188
 189         vuser->vuid = next_vuid;
 190
 191         if (!server_info) {
 192                 next_vuid++;
 193                 num_validated_vuids++;
 194
 195                 vuser->server_info = NULL;
 196
 197                 DLIST_ADD(validated_users, vuser);
 198
 199                 return vuser->vuid;
 200         }
 201
 202         /* the next functions should be done by a SID mapping system (SMS) as
 203          * the new real sam db won't have reference to unix uids or gids
 204          */
 205
 206         vuser->uid = server_info->uid;
 207         vuser->gid = server_info->gid;
 208
 209         vuser->n_groups = server_info->n_groups;
 210         if (vuser->n_groups) {
 211                 if (!(vuser->groups = (gid_t *)memdup(server_info->groups,
 212                                                       sizeof(gid_t) *
 213                                                       vuser->n_groups))) {
 214                         DEBUG(0,("register_vuid: failed to memdup "
 215                                  "vuser->groups\n"));
 216                         data_blob_free(&session_key);
 217                         free(vuser);
 218                         talloc_free(server_info);
 219                         return UID_FIELD_INVALID;
 220                 }
 221         }
 222
 223         vuser->guest = server_info->guest;
 224         fstrcpy(vuser->user.unix_name, server_info->unix_name);
 225
 226         /* This is a potentially untrusted username */
 227         alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$",
 228                      sizeof(vuser->user.smb_name));
 229
 230         fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
 231         fstrcpy(vuser->user.full_name,
 232                 pdb_get_fullname(server_info->sam_account));
 233
 234         {
 235                 /* Keep the homedir handy */
 236                 const char *homedir =
 237                         pdb_get_homedir(server_info->sam_account);
 238                 const char *logon_script =
 239                         pdb_get_logon_script(server_info->sam_account);
 240
 241                 if (!IS_SAM_DEFAULT(server_info->sam_account,
 242                                     PDB_UNIXHOMEDIR)) {
 243                         const char *unix_homedir =
 244                                 pdb_get_unix_homedir(server_info->sam_account);
 245                         if (unix_homedir) {
 246                                 vuser->unix_homedir =
 247                                         smb_xstrdup(unix_homedir);
 248                         }
 249                 } else {
 250                         struct passwd *passwd =
 251                                 getpwnam_alloc(NULL, vuser->user.unix_name);
 252                         if (passwd) {
 253                                 vuser->unix_homedir =
 254                                         smb_xstrdup(passwd->pw_dir);
 255                                 talloc_free(passwd);
 256                         }
 257                 }
 258
 259                 if (homedir) {
 260                         vuser->homedir = smb_xstrdup(homedir);
 261                 }
 262                 if (logon_script) {
 263                         vuser->logon_script = smb_xstrdup(logon_script);
 264                 }
 265         }
 266
 267         vuser->session_key = session_key;
 268
 269         DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n",
 270                   (unsigned int)vuser->uid,
 271                   (unsigned int)vuser->gid,
 272                   vuser->user.unix_name, vuser->user.smb_name,
 273                   vuser->user.domain, vuser->guest ));
 274
 275         DEBUG(3, ("User name: %s\tReal name: %s\n", vuser->user.unix_name,
 276                   vuser->user.full_name));
 277
 278         if (server_info->ptok) {
 279                 vuser->nt_user_token = dup_nt_token(NULL, server_info->ptok);
 280         } else {
 281                 DEBUG(1, ("server_info does not contain a user_token - "
 282                           "cannot continue\n"));
 283                 talloc_free(server_info);
 284                 data_blob_free(&session_key);
 285                 SAFE_FREE(vuser->homedir);
 286                 SAFE_FREE(vuser->unix_homedir);
 287                 SAFE_FREE(vuser->logon_script);
 288
 289                 SAFE_FREE(vuser);
 290                 return UID_FIELD_INVALID;
 291         }
 292
 293         /* use this to keep tabs on all our info from the authentication */
 294         vuser->server_info = server_info;
 295
 296         DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",
 297                  (int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 298
 299         next_vuid++;
 300         num_validated_vuids++;
 301
 302         DLIST_ADD(validated_users, vuser);
 303
 304         if (!session_claim(vuser)) {
 305                 DEBUG(1, ("Failed to claim session for vuid=%d\n",
 306                           vuser->vuid));
 307                 invalidate_vuid(vuser->vuid);
 308                 return -1;
 309         }
 310
 311         /* Register a home dir service for this user iff
 312
 313            (a) This is not a guest connection,
 314            (b) we have a home directory defined
 315            (c) there s not an existing static share by that name
 316
 317            If a share exists by this name (autoloaded or not) reuse it . */
 318
 319         vuser->homes_snum = -1;
 320
 321         if ( (!vuser->guest) && vuser->unix_homedir && *(vuser->unix_homedir))
 322         {
 323                 int servicenumber = lp_servicenumber(vuser->user.unix_name);
 324
 325                 if ( servicenumber == -1 ) {
 326                         DEBUG(3, ("Adding homes service for user '%s' using "
 327                                   "home directory: '%s'\n",
 328                                 vuser->user.unix_name, vuser->unix_homedir));
 329                         vuser->homes_snum =
 330                                 add_home_service(vuser->user.unix_name,
 331                                                  vuser->user.unix_name,
 332                                                  vuser->unix_homedir);
 333                 } else {
 334                         DEBUG(3, ("Using static (or previously created) "
 335                                   "service for user '%s'; path = '%s'\n",
 336                                   vuser->user.unix_name,
 337                                   lp_pathname(servicenumber) ));
 338                         vuser->homes_snum = servicenumber;
 339                 }
 340         }
 341
 342         if (srv_is_signing_negotiated() && !vuser->guest &&
 343             !srv_signing_started()) {
 344                 /* Try and turn on server signing on the first non-guest
 345                  * sessionsetup. */
 346                 srv_set_signing(vuser->session_key, response_blob);
 347         }
 348
 349         /* fill in the current_user_info struct */
 350         set_current_user_info( &vuser->user );
 351
 352
 353         return vuser->vuid;
 354 }
 355
 356 /****************************************************************************
 357  Add a name to the session users list.
 358 ****************************************************************************/
 359
 360 void add_session_user(const char *user)
 361 {
 362         fstring suser;
 363         struct passwd *passwd;
 364
 365         if (!(passwd = Get_Pwnam(user)))
 366                 return;
 367
 368         fstrcpy(suser,passwd->pw_name);
 369
 370         if(!*suser)
 371                 return;
 372
 373         if( session_userlist && in_list(suser,session_userlist,False) )
 374                 return;
 375
 376         if( !session_userlist ||
 377             (strlen(suser) + strlen(session_userlist) + 2 >=
 378              len_session_userlist) ) {
 379                 char *newlist;
 380
 381                 if (len_session_userlist > 128 * PSTRING_LEN) {
 382                         DEBUG(3,("add_session_user: session userlist already "
 383                                  "too large.\n"));
 384                         return;
 385                 }
 386                 newlist = (char *)SMB_REALLOC(
 387                         session_userlist,
 388                         len_session_userlist + PSTRING_LEN );
 389                 if( newlist == NULL ) {
 390                         DEBUG(1,("Unable to resize session_userlist\n"));
 391                         return;
 392                 }
 393                 if (!session_userlist) {
 394                         *newlist = '\0';
 395                 }
 396                 session_userlist = newlist;
 397                 len_session_userlist += PSTRING_LEN;
 398         }
 399
 400         safe_strcat(session_userlist," ",len_session_userlist-1);
 401         safe_strcat(session_userlist,suser,len_session_userlist-1);
 402 }
 403
 404 /****************************************************************************
 405  Check if a username is valid.
 406 ****************************************************************************/
 407
 408 static BOOL user_ok(const char *user, int snum)
 409 {
 410         char **valid, **invalid;
 411         BOOL ret;
 412
 413         valid = invalid = NULL;
 414         ret = True;
 415
 416         if (lp_invalid_users(snum)) {
 417                 str_list_copy(&invalid, lp_invalid_users(snum));
 418                 if (invalid &&
 419                     str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 420                         if ( invalid &&
 421                              str_list_sub_basic(invalid,
 422                                                 current_user_info.smb_name) ) {
 423                                 ret = !user_in_list(user,
 424                                                     (const char **)invalid);
 425                         }
 426                 }
 427         }
 428         if (invalid)
 429                 str_list_free (&invalid);
 430
 431         if (ret && lp_valid_users(snum)) {
 432                 str_list_copy(&valid, lp_valid_users(snum));
 433                 if ( valid &&
 434                      str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 435                         if ( valid &&
 436                              str_list_sub_basic(valid,
 437                                                 current_user_info.smb_name) ) {
 438                                 ret = user_in_list(user, (const char **)valid);
 439                         }
 440                 }
 441         }
 442         if (valid)
 443                 str_list_free (&valid);
 444
 445         if (ret && lp_onlyuser(snum)) {
 446                 char **user_list = str_list_make (lp_username(snum), NULL);
 447                 if (user_list &&
 448                     str_list_substitute(user_list, "%S",
 449                                         lp_servicename(snum))) {
 450                         ret = user_in_list(user, (const char **)user_list);
 451                 }
 452                 if (user_list) str_list_free (&user_list);
 453         }
 454
 455         return(ret);
 456 }
 457
 458 /****************************************************************************
 459  Validate a group username entry. Return the username or NULL.
 460 ****************************************************************************/
 461
 462 static char *validate_group(char *group, DATA_BLOB password,int snum)
 463 {
 464 #ifdef HAVE_NETGROUP
 465         {
 466                 char *host, *user, *domain;
 467                 setnetgrent(group);
 468                 while (getnetgrent(&host, &user, &domain)) {
 469                         if (user) {
 470                                 if (user_ok(user, snum) &&
 471                                     password_ok(user,password)) {
 472                                         endnetgrent();
 473                                         return(user);
 474                                 }
 475                         }
 476                 }
 477                 endnetgrent();
 478         }
 479 #endif
 480
 481 #ifdef HAVE_GETGRENT
 482         {
 483                 struct group *gptr;
 484                 setgrent();
 485                 while ((gptr = (struct group *)getgrent())) {
 486                         if (strequal(gptr->gr_name,group))
 487                                 break;
 488                 }
 489
 490                 /*
 491                  * As user_ok can recurse doing a getgrent(), we must
 492                  * copy the member list into a pstring on the stack before
 493                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 494                  */
 495
 496                 if (gptr) {
 497                         pstring member_list;
 498                         char *member;
 499                         size_t copied_len = 0;
 500                         int i;
 501
 502                         *member_list = '\0';
 503                         member = member_list;
 504
 505                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 506                                 size_t member_len = strlen(gptr->gr_mem[i])+1;
 507                                 if(copied_len+member_len < sizeof(pstring)) {
 508
 509                                         DEBUG(10,("validate_group: = gr_mem = "
 510                                                   "%s\n", gptr->gr_mem[i]));
 511
 512                                         safe_strcpy(member, gptr->gr_mem[i],
 513                                                     sizeof(pstring) -
 514                                                     copied_len - 1);
 515                                         copied_len += member_len;
 516                                         member += copied_len;
 517                                 } else {
 518                                         *member = '\0';
 519                                 }
 520                         }
 521
 522                         endgrent();
 523
 524                         member = member_list;
 525                         while (*member) {
 526                                 static fstring name;
 527                                 fstrcpy(name,member);
 528                                 if (user_ok(name,snum) &&
 529                                     password_ok(name,password)) {
 530                                         endgrent();
 531                                         return(&name[0]);
 532                                 }
 533
 534                                 DEBUG(10,("validate_group = member = %s\n",
 535                                           member));
 536
 537                                 member += strlen(member) + 1;
 538                         }
 539                 } else {
 540                         endgrent();
 541                         return NULL;
 542                 }
 543         }
 544 #endif
 545         return(NULL);
 546 }
 547
 548 /****************************************************************************
 549  Check for authority to login to a service with a given username/password.
 550  Note this is *NOT* used when logging on using sessionsetup_and_X.
 551 ****************************************************************************/
 552
 553 BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 554                      BOOL *guest)
 555 {
 556         BOOL ok = False;
 557
 558 #ifdef DEBUG_PASSWORD
 559         DEBUG(100,("authorise_login: checking authorisation on "
 560                    "user=%s pass=%s\n", user,password.data));
 561 #endif
 562
 563         *guest = False;
 564
 565         /* there are several possibilities:
 566                 1) login as the given user with given password
 567                 2) login as a previously registered username with the given
 568                    password
 569                 3) login as a session list username with the given password
 570                 4) login as a previously validated user/password pair
 571                 5) login as the "user =" user with given password
 572                 6) login as the "user =" user with no password
 573                    (guest connection)
 574                 7) login as guest user with no password
 575
 576                 if the service is guest_only then steps 1 to 5 are skipped
 577         */
 578
 579         /* now check the list of session users */
 580         if (!ok) {
 581                 char *auser;
 582                 char *user_list = NULL;
 583
 584                 if ( session_userlist )
 585                         user_list = SMB_STRDUP(session_userlist);
 586                 else
 587                         user_list = SMB_STRDUP("");
 588
 589                 if (!user_list)
 590                         return(False);
 591
 592                 for (auser=strtok(user_list,LIST_SEP); !ok && auser;
 593                      auser = strtok(NULL,LIST_SEP)) {
 594                         fstring user2;
 595                         fstrcpy(user2,auser);
 596                         if (!user_ok(user2,snum))
 597                                 continue;
 598
 599                         if (password_ok(user2,password)) {
 600                                 ok = True;
 601                                 fstrcpy(user,user2);
 602                                 DEBUG(3,("authorise_login: ACCEPTED: session "
 603                                          "list username (%s) and given "
 604                                          "password ok\n", user));
 605                         }
 606                 }
 607
 608                 SAFE_FREE(user_list);
 609         }
 610
 611         /* check the user= fields and the given password */
 612         if (!ok && lp_username(snum)) {
 613                 char *auser;
 614                 pstring user_list;
 615                 pstrcpy(user_list,lp_username(snum));
 616
 617                 pstring_sub(user_list,"%S",lp_servicename(snum));
 618
 619                 for (auser=strtok(user_list,LIST_SEP); auser && !ok;
 620                      auser = strtok(NULL,LIST_SEP)) {
 621                         if (*auser == '@') {
 622                                 auser = validate_group(auser+1,password,snum);
 623                                 if (auser) {
 624                                         ok = True;
 625                                         fstrcpy(user,auser);
 626                                         DEBUG(3,("authorise_login: ACCEPTED: "
 627                                                  "group username and given "
 628                                                  "password ok (%s)\n", user));
 629                                 }
 630                         } else {
 631                                 fstring user2;
 632                                 fstrcpy(user2,auser);
 633                                 if (user_ok(user2,snum) &&
 634                                     password_ok(user2,password)) {
 635                                         ok = True;
 636                                         fstrcpy(user,user2);
 637                                         DEBUG(3,("authorise_login: ACCEPTED: "
 638                                                  "user list username and "
 639                                                  "given password ok (%s)\n",
 640                                                  user));
 641                                 }
 642                         }
 643                 }
 644         }
 645
 646         /* check for a normal guest connection */
 647         if (!ok && GUEST_OK(snum)) {
 648                 fstring guestname;
 649                 fstrcpy(guestname,lp_guestaccount());
 650                 if (Get_Pwnam(guestname)) {
 651                         fstrcpy(user,guestname);
 652                         ok = True;
 653                         DEBUG(3,("authorise_login: ACCEPTED: guest account "
 654                                  "and guest ok (%s)\n", user));
 655                 } else {
 656                         DEBUG(0,("authorise_login: Invalid guest account "
 657                                  "%s??\n",guestname));
 658                 }
 659                 *guest = True;
 660         }
 661
 662         if (ok && !user_ok(user, snum)) {
 663                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 664                 ok = False;
 665         }
 666
 667         return(ok);
 668 }