source/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         free_server_info(&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         delete_nt_token(&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 'owned' by register_vuid)
 140  *
 141  *  @param respose_blob The NT challenge-response, if available.  (May be freed after this call)
 142  *
 143  *  @param smb_name The untranslated name of the user
 144  *
 145  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 146  *   tell random client vuid's (normally zero) from valid vuids.)
 147  *
 148  */
 149
 150 int register_vuid(auth_serversupplied_info *server_info, DATA_BLOB session_key, DATA_BLOB response_blob, const char *smb_name)
 151 {
 152         user_struct *vuser = NULL;
 153
 154         /* Ensure no vuid gets registered in share level security. */
 155         if(lp_security() == SEC_SHARE) {
 156                 data_blob_free(&session_key);
 157                 return UID_FIELD_INVALID;
 158         }
 159
 160         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 161         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 162                 data_blob_free(&session_key);
 163                 return UID_FIELD_INVALID;
 164         }
 165
 166         if((vuser = SMB_MALLOC_P(user_struct)) == NULL) {
 167                 DEBUG(0,("Failed to malloc users struct!\n"));
 168                 data_blob_free(&session_key);
 169                 return UID_FIELD_INVALID;
 170         }
 171
 172         ZERO_STRUCTP(vuser);
 173
 174         /* Allocate a free vuid. Yes this is a linear search... :-) */
 175         while( get_valid_user_struct(next_vuid) != NULL ) {
 176                 next_vuid++;
 177                 /* Check for vuid wrap. */
 178                 if (next_vuid == UID_FIELD_INVALID)
 179                         next_vuid = VUID_OFFSET;
 180         }
 181
 182         DEBUG(10,("register_vuid: allocated vuid = %u\n", (unsigned int)next_vuid ));
 183
 184         vuser->vuid = next_vuid;
 185
 186         if (!server_info) {
 187                 next_vuid++;
 188                 num_validated_vuids++;
 189
 190                 vuser->server_info = NULL;
 191
 192                 DLIST_ADD(validated_users, vuser);
 193
 194                 return vuser->vuid;
 195         }
 196
 197         /* the next functions should be done by a SID mapping system (SMS) as
 198          * the new real sam db won't have reference to unix uids or gids
 199          */
 200
 201         vuser->uid = server_info->uid;
 202         vuser->gid = server_info->gid;
 203
 204         vuser->n_groups = server_info->n_groups;
 205         if (vuser->n_groups) {
 206                 if (!(vuser->groups = (gid_t *)memdup(server_info->groups, sizeof(gid_t) * vuser->n_groups))) {
 207                         DEBUG(0,("register_vuid: failed to memdup vuser->groups\n"));
 208                         data_blob_free(&session_key);
 209                         free(vuser);
 210                         free_server_info(&server_info);
 211                         return UID_FIELD_INVALID;
 212                 }
 213         }
 214
 215         vuser->guest = server_info->guest;
 216         fstrcpy(vuser->user.unix_name, server_info->unix_name);
 217
 218         /* This is a potentially untrusted username */
 219         alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$", sizeof(vuser->user.smb_name));
 220
 221         fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
 222         fstrcpy(vuser->user.full_name, pdb_get_fullname(server_info->sam_account));
 223
 224         {
 225                 /* Keep the homedir handy */
 226                 const char *homedir = pdb_get_homedir(server_info->sam_account);
 227                 const char *logon_script = pdb_get_logon_script(server_info->sam_account);
 228
 229                 if (!IS_SAM_DEFAULT(server_info->sam_account, PDB_UNIXHOMEDIR)) {
 230                         const char *unix_homedir = pdb_get_unix_homedir(server_info->sam_account);
 231                         if (unix_homedir) {
 232                                 vuser->unix_homedir = smb_xstrdup(unix_homedir);
 233                         }
 234                 } else {
 235                         struct passwd *passwd = getpwnam_alloc(vuser->user.unix_name);
 236                         if (passwd) {
 237                                 vuser->unix_homedir = smb_xstrdup(passwd->pw_dir);
 238                                 passwd_free(&passwd);
 239                         }
 240                 }
 241
 242                 if (homedir) {
 243                         vuser->homedir = smb_xstrdup(homedir);
 244                 }
 245                 if (logon_script) {
 246                         vuser->logon_script = smb_xstrdup(logon_script);
 247                 }
 248         }
 249
 250         vuser->session_key = session_key;
 251
 252         DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n",
 253                   (unsigned int)vuser->uid,
 254                   (unsigned int)vuser->gid,
 255                   vuser->user.unix_name, vuser->user.smb_name, vuser->user.domain, vuser->guest ));
 256
 257         DEBUG(3, ("User name: %s\tReal name: %s\n",vuser->user.unix_name,vuser->user.full_name));
 258
 259         if (server_info->ptok) {
 260                 vuser->nt_user_token = dup_nt_token(server_info->ptok);
 261         } else {
 262                 DEBUG(1, ("server_info does not contain a user_token - cannot continue\n"));
 263                 free_server_info(&server_info);
 264                 data_blob_free(&session_key);
 265                 SAFE_FREE(vuser->homedir);
 266                 SAFE_FREE(vuser->unix_homedir);
 267                 SAFE_FREE(vuser->logon_script);
 268
 269                 SAFE_FREE(vuser);
 270                 return UID_FIELD_INVALID;
 271         }
 272
 273         /* use this to keep tabs on all our info from the authentication */
 274         vuser->server_info = server_info;
 275
 276         DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",(int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 277
 278         next_vuid++;
 279         num_validated_vuids++;
 280
 281         DLIST_ADD(validated_users, vuser);
 282
 283         if (!session_claim(vuser)) {
 284                 DEBUG(1,("Failed to claim session for vuid=%d\n", vuser->vuid));
 285                 invalidate_vuid(vuser->vuid);
 286                 return -1;
 287         }
 288
 289         /* Register a home dir service for this user iff
 290
 291            (a) This is not a guest connection,
 292            (b) we have a home directory defined
 293            (c) there s not an existing static share by that name
 294
 295            If a share exists by this name (autoloaded or not) reuse it . */
 296
 297         vuser->homes_snum = -1;
 298
 299         if ( (!vuser->guest) && vuser->unix_homedir && *(vuser->unix_homedir))
 300         {
 301                 int servicenumber = lp_servicenumber(vuser->user.unix_name);
 302
 303                 if ( servicenumber == -1 ) {
 304                         DEBUG(3, ("Adding homes service for user '%s' using home directory: '%s'\n",
 305                                 vuser->user.unix_name, vuser->unix_homedir));
 306                         vuser->homes_snum = add_home_service(vuser->user.unix_name,
 307                                                 vuser->user.unix_name, vuser->unix_homedir);
 308                 } else {
 309                         DEBUG(3, ("Using static (or previously created) service for user '%s'; path = '%s'\n",
 310                                 vuser->user.unix_name, lp_pathname(servicenumber) ));
 311                         vuser->homes_snum = servicenumber;
 312                 }
 313         }
 314
 315         if (srv_is_signing_negotiated() && !vuser->guest && !srv_signing_started()) {
 316                 /* Try and turn on server signing on the first non-guest sessionsetup. */
 317                 srv_set_signing(vuser->session_key, response_blob);
 318         }
 319
 320         /* fill in the current_user_info struct */
 321         set_current_user_info( &vuser->user );
 322
 323
 324         return vuser->vuid;
 325 }
 326
 327 /****************************************************************************
 328  Add a name to the session users list.
 329 ****************************************************************************/
 330
 331 void add_session_user(const char *user)
 332 {
 333         fstring suser;
 334         struct passwd *passwd;
 335
 336         if (!(passwd = Get_Pwnam(user)))
 337                 return;
 338
 339         fstrcpy(suser,passwd->pw_name);
 340
 341         if(!*suser)
 342                 return;
 343
 344         if( session_userlist && in_list(suser,session_userlist,False) )
 345                 return;
 346
 347         if( !session_userlist || (strlen(suser) + strlen(session_userlist) + 2 >= len_session_userlist) ) {
 348                 char *newlist;
 349
 350                 if (len_session_userlist > 128 * PSTRING_LEN) {
 351                         DEBUG(3,("add_session_user: session userlist already too large.\n"));
 352                         return;
 353                 }
 354                 newlist = (char *)SMB_REALLOC( session_userlist, len_session_userlist + PSTRING_LEN );
 355                 if( newlist == NULL ) {
 356                         DEBUG(1,("Unable to resize session_userlist\n"));
 357                         return;
 358                 }
 359                 if (!session_userlist) {
 360                         *newlist = '\0';
 361                 }
 362                 session_userlist = newlist;
 363                 len_session_userlist += PSTRING_LEN;
 364         }
 365
 366         safe_strcat(session_userlist," ",len_session_userlist-1);
 367         safe_strcat(session_userlist,suser,len_session_userlist-1);
 368 }
 369
 370 /****************************************************************************
 371  Check if a username is valid.
 372 ****************************************************************************/
 373
 374 BOOL user_ok(const char *user,int snum, gid_t *groups, size_t n_groups)
 375 {
 376         char **valid, **invalid;
 377         BOOL ret;
 378
 379         valid = invalid = NULL;
 380         ret = True;
 381
 382         if (lp_invalid_users(snum)) {
 383                 str_list_copy(&invalid, lp_invalid_users(snum));
 384                 if (invalid && str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 385                         if ( invalid && str_list_sub_basic(invalid, current_user_info.smb_name) ) {
 386                                 ret = !user_in_list(user, (const char **)invalid, groups, n_groups);
 387                         }
 388                 }
 389         }
 390         if (invalid)
 391                 str_list_free (&invalid);
 392
 393         if (ret && lp_valid_users(snum)) {
 394                 str_list_copy(&valid, lp_valid_users(snum));
 395                 if ( valid && str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 396                         if ( valid && str_list_sub_basic(valid, current_user_info.smb_name) ) {
 397                                 ret = user_in_list(user, (const char **)valid, groups, n_groups);
 398                         }
 399                 }
 400         }
 401         if (valid)
 402                 str_list_free (&valid);
 403
 404         if (ret && lp_onlyuser(snum)) {
 405                 char **user_list = str_list_make (lp_username(snum), NULL);
 406                 if (user_list && str_list_substitute(user_list, "%S", lp_servicename(snum))) {
 407                         ret = user_in_list(user, (const char **)user_list, groups, n_groups);
 408                 }
 409                 if (user_list) str_list_free (&user_list);
 410         }
 411
 412         return(ret);
 413 }
 414
 415 /****************************************************************************
 416  Validate a group username entry. Return the username or NULL.
 417 ****************************************************************************/
 418
 419 static char *validate_group(char *group, DATA_BLOB password,int snum)
 420 {
 421 #ifdef HAVE_NETGROUP
 422         {
 423                 char *host, *user, *domain;
 424                 setnetgrent(group);
 425                 while (getnetgrent(&host, &user, &domain)) {
 426                         if (user) {
 427                                 if (user_ok(user, snum, NULL, 0) &&
 428                                     password_ok(user,password)) {
 429                                         endnetgrent();
 430                                         return(user);
 431                                 }
 432                         }
 433                 }
 434                 endnetgrent();
 435         }
 436 #endif
 437
 438 #ifdef HAVE_GETGRENT
 439         {
 440                 struct group *gptr;
 441                 setgrent();
 442                 while ((gptr = (struct group *)getgrent())) {
 443                         if (strequal(gptr->gr_name,group))
 444                                 break;
 445                 }
 446
 447                 /*
 448                  * As user_ok can recurse doing a getgrent(), we must
 449                  * copy the member list into a pstring on the stack before
 450                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 451                  */
 452
 453                 if (gptr) {
 454                         pstring member_list;
 455                         char *member;
 456                         size_t copied_len = 0;
 457                         int i;
 458
 459                         *member_list = '\0';
 460                         member = member_list;
 461
 462                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 463                                 size_t member_len = strlen(gptr->gr_mem[i]) + 1;
 464                                 if( copied_len + member_len < sizeof(pstring)) {
 465
 466                                         DEBUG(10,("validate_group: = gr_mem = %s\n", gptr->gr_mem[i]));
 467
 468                                         safe_strcpy(member, gptr->gr_mem[i], sizeof(pstring) - copied_len - 1);
 469                                         copied_len += member_len;
 470                                         member += copied_len;
 471                                 } else {
 472                                         *member = '\0';
 473                                 }
 474                         }
 475
 476                         endgrent();
 477
 478                         member = member_list;
 479                         while (*member) {
 480                                 static fstring name;
 481                                 fstrcpy(name,member);
 482                                 if (user_ok(name,snum, NULL, 0) &&
 483                                     password_ok(name,password)) {
 484                                         endgrent();
 485                                         return(&name[0]);
 486                                 }
 487
 488                                 DEBUG(10,("validate_group = member = %s\n", member));
 489
 490                                 member += strlen(member) + 1;
 491                         }
 492                 } else {
 493                         endgrent();
 494                         return NULL;
 495                 }
 496         }
 497 #endif
 498         return(NULL);
 499 }
 500
 501 /****************************************************************************
 502  Check for authority to login to a service with a given username/password.
 503  Note this is *NOT* used when logging on using sessionsetup_and_X.
 504 ****************************************************************************/
 505
 506 BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 507                      BOOL *guest)
 508 {
 509         BOOL ok = False;
 510
 511 #ifdef DEBUG_PASSWORD
 512         DEBUG(100,("authorise_login: checking authorisation on user=%s pass=%s\n",
 513                    user,password.data));
 514 #endif
 515
 516         *guest = False;
 517
 518         /* there are several possibilities:
 519                 1) login as the given user with given password
 520                 2) login as a previously registered username with the given password
 521                 3) login as a session list username with the given password
 522                 4) login as a previously validated user/password pair
 523                 5) login as the "user =" user with given password
 524                 6) login as the "user =" user with no password (guest connection)
 525                 7) login as guest user with no password
 526
 527                 if the service is guest_only then steps 1 to 5 are skipped
 528         */
 529
 530         /* now check the list of session users */
 531         if (!ok) {
 532                 char *auser;
 533                 char *user_list = NULL;
 534
 535                 if ( session_userlist )
 536                         user_list = SMB_STRDUP(session_userlist);
 537                 else
 538                         user_list = SMB_STRDUP("");
 539
 540                 if (!user_list)
 541                         return(False);
 542
 543                 for (auser=strtok(user_list,LIST_SEP); !ok && auser;
 544                      auser = strtok(NULL,LIST_SEP)) {
 545                         fstring user2;
 546                         fstrcpy(user2,auser);
 547                         if (!user_ok(user2,snum, NULL, 0))
 548                                 continue;
 549
 550                         if (password_ok(user2,password)) {
 551                                 ok = True;
 552                                 fstrcpy(user,user2);
 553                                 DEBUG(3,("authorise_login: ACCEPTED: session list username (%s) \
 554 and given password ok\n", user));
 555                         }
 556                 }
 557
 558                 SAFE_FREE(user_list);
 559         }
 560
 561         /* check the user= fields and the given password */
 562         if (!ok && lp_username(snum)) {
 563                 char *auser;
 564                 pstring user_list;
 565                 pstrcpy(user_list,lp_username(snum));
 566
 567                 pstring_sub(user_list,"%S",lp_servicename(snum));
 568
 569                 for (auser=strtok(user_list,LIST_SEP); auser && !ok;
 570                      auser = strtok(NULL,LIST_SEP)) {
 571                         if (*auser == '@') {
 572                                 auser = validate_group(auser+1,password,snum);
 573                                 if (auser) {
 574                                         ok = True;
 575                                         fstrcpy(user,auser);
 576                                         DEBUG(3,("authorise_login: ACCEPTED: group username \
 577 and given password ok (%s)\n", user));
 578                                 }
 579                         } else {
 580                                 fstring user2;
 581                                 fstrcpy(user2,auser);
 582                                 if (user_ok(user2,snum, NULL, 0) && password_ok(user2,password)) {
 583                                         ok = True;
 584                                         fstrcpy(user,user2);
 585                                         DEBUG(3,("authorise_login: ACCEPTED: user list username \
 586 and given password ok (%s)\n", user));
 587                                 }
 588                         }
 589                 }
 590         }
 591
 592         /* check for a normal guest connection */
 593         if (!ok && GUEST_OK(snum)) {
 594                 fstring guestname;
 595                 fstrcpy(guestname,lp_guestaccount());
 596                 if (Get_Pwnam(guestname)) {
 597                         fstrcpy(user,guestname);
 598                         ok = True;
 599                         DEBUG(3,("authorise_login: ACCEPTED: guest account and guest ok (%s)\n",
 600                                         user));
 601                 } else {
 602                         DEBUG(0,("authorise_login: Invalid guest account %s??\n",guestname));
 603                 }
 604                 *guest = True;
 605         }
 606
 607         if (ok && !user_ok(user, snum, NULL, 0)) {
 608                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 609                 ok = False;
 610         }
 611
 612         return(ok);
 613 }