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) {
  51                         if (count > 10) {
  52                                 DLIST_PROMOTE(validated_users, usp);
  53                         }
  54                         return usp;
  55                 }
  56         }
  57
  58         return NULL;
  59 }
  60
  61 /****************************************************************************
  62  Invalidate a uid.
  63 ****************************************************************************/
  64
  65 void invalidate_vuid(uint16 vuid)
  66 {
  67         user_struct *vuser = get_valid_user_struct(vuid);
  68
  69         if (vuser == NULL)
  70                 return;
  71
  72         SAFE_FREE(vuser->homedir);
  73         SAFE_FREE(vuser->unix_homedir);
  74         SAFE_FREE(vuser->logon_script);
  75
  76         session_yield(vuser);
  77         SAFE_FREE(vuser->session_keystr);
  78
  79         free_server_info(&vuser->server_info);
  80
  81         data_blob_free(&vuser->session_key);
  82
  83         DLIST_REMOVE(validated_users, vuser);
  84
  85         /* clear the vuid from the 'cache' on each connection, and
  86            from the vuid 'owner' of connections */
  87         conn_clear_vuid_cache(vuid);
  88
  89         SAFE_FREE(vuser->groups);
  90         delete_nt_token(&vuser->nt_user_token);
  91         SAFE_FREE(vuser);
  92         num_validated_vuids--;
  93 }
  94
  95 /****************************************************************************
  96  Invalidate all vuid entries for this process.
  97 ****************************************************************************/
  98
  99 void invalidate_all_vuids(void)
 100 {
 101         user_struct *usp, *next=NULL;
 102
 103         for (usp=validated_users;usp;usp=next) {
 104                 next = usp->next;
 105
 106                 invalidate_vuid(usp->vuid);
 107         }
 108 }
 109
 110 /**
 111  *  register that a valid login has been performed, establish 'session'.
 112  *  @param server_info The token returned from the authentication process.
 113  *   (now 'owned' by register_vuid)
 114  *
 115  *  @param session_key The User session key for the login session (now also 'owned' by register_vuid)
 116  *
 117  *  @param respose_blob The NT challenge-response, if available.  (May be freed after this call)
 118  *
 119  *  @param smb_name The untranslated name of the user
 120  *
 121  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 122  *   tell random client vuid's (normally zero) from valid vuids.)
 123  *
 124  */
 125
 126 int register_vuid(auth_serversupplied_info *server_info, DATA_BLOB session_key, DATA_BLOB response_blob, const char *smb_name)
 127 {
 128         user_struct *vuser = NULL;
 129
 130         /* Ensure no vuid gets registered in share level security. */
 131         if(lp_security() == SEC_SHARE) {
 132                 data_blob_free(&session_key);
 133                 return UID_FIELD_INVALID;
 134         }
 135
 136         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 137         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 138                 data_blob_free(&session_key);
 139                 return UID_FIELD_INVALID;
 140         }
 141
 142         if((vuser = SMB_MALLOC_P(user_struct)) == NULL) {
 143                 DEBUG(0,("Failed to malloc users struct!\n"));
 144                 data_blob_free(&session_key);
 145                 return UID_FIELD_INVALID;
 146         }
 147
 148         ZERO_STRUCTP(vuser);
 149
 150         /* Allocate a free vuid. Yes this is a linear search... :-) */
 151         while( get_valid_user_struct(next_vuid) != NULL ) {
 152                 next_vuid++;
 153                 /* Check for vuid wrap. */
 154                 if (next_vuid == UID_FIELD_INVALID)
 155                         next_vuid = VUID_OFFSET;
 156         }
 157
 158         DEBUG(10,("register_vuid: allocated vuid = %u\n", (unsigned int)next_vuid ));
 159
 160         vuser->vuid = next_vuid;
 161
 162         /* the next functions should be done by a SID mapping system (SMS) as
 163          * the new real sam db won't have reference to unix uids or gids
 164          */
 165
 166         vuser->uid = server_info->uid;
 167         vuser->gid = server_info->gid;
 168
 169         vuser->n_groups = server_info->n_groups;
 170         if (vuser->n_groups) {
 171                 if (!(vuser->groups = memdup(server_info->groups, sizeof(gid_t) * vuser->n_groups))) {
 172                         DEBUG(0,("register_vuid: failed to memdup vuser->groups\n"));
 173                         data_blob_free(&session_key);
 174                         free(vuser);
 175                         free_server_info(&server_info);
 176                         return UID_FIELD_INVALID;
 177                 }
 178         }
 179
 180         vuser->guest = server_info->guest;
 181         fstrcpy(vuser->user.unix_name, server_info->unix_name);
 182
 183         /* This is a potentially untrusted username */
 184         alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$", sizeof(vuser->user.smb_name));
 185
 186         fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
 187         fstrcpy(vuser->user.full_name, pdb_get_fullname(server_info->sam_account));
 188
 189         {
 190                 /* Keep the homedir handy */
 191                 const char *homedir = pdb_get_homedir(server_info->sam_account);
 192                 const char *logon_script = pdb_get_logon_script(server_info->sam_account);
 193
 194                 if (!IS_SAM_DEFAULT(server_info->sam_account, PDB_UNIXHOMEDIR)) {
 195                         const char *unix_homedir = pdb_get_unix_homedir(server_info->sam_account);
 196                         if (unix_homedir) {
 197                                 vuser->unix_homedir = smb_xstrdup(unix_homedir);
 198                         }
 199                 } else {
 200                         struct passwd *passwd = getpwnam_alloc(vuser->user.unix_name);
 201                         if (passwd) {
 202                                 vuser->unix_homedir = smb_xstrdup(passwd->pw_dir);
 203                                 passwd_free(&passwd);
 204                         }
 205                 }
 206
 207                 if (homedir) {
 208                         vuser->homedir = smb_xstrdup(homedir);
 209                 }
 210                 if (logon_script) {
 211                         vuser->logon_script = smb_xstrdup(logon_script);
 212                 }
 213         }
 214
 215         vuser->session_key = session_key;
 216
 217         DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n",
 218                   (unsigned int)vuser->uid,
 219                   (unsigned int)vuser->gid,
 220                   vuser->user.unix_name, vuser->user.smb_name, vuser->user.domain, vuser->guest ));
 221
 222         DEBUG(3, ("User name: %s\tReal name: %s\n",vuser->user.unix_name,vuser->user.full_name));
 223
 224         if (server_info->ptok) {
 225                 vuser->nt_user_token = dup_nt_token(server_info->ptok);
 226         } else {
 227                 DEBUG(1, ("server_info does not contain a user_token - cannot continue\n"));
 228                 free_server_info(&server_info);
 229                 data_blob_free(&session_key);
 230                 SAFE_FREE(vuser->homedir);
 231                 SAFE_FREE(vuser->unix_homedir);
 232                 SAFE_FREE(vuser->logon_script);
 233
 234                 SAFE_FREE(vuser);
 235                 return UID_FIELD_INVALID;
 236         }
 237
 238         /* use this to keep tabs on all our info from the authentication */
 239         vuser->server_info = server_info;
 240
 241         DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",(int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 242
 243         next_vuid++;
 244         num_validated_vuids++;
 245
 246         DLIST_ADD(validated_users, vuser);
 247
 248         if (!session_claim(vuser)) {
 249                 DEBUG(1,("Failed to claim session for vuid=%d\n", vuser->vuid));
 250                 invalidate_vuid(vuser->vuid);
 251                 return -1;
 252         }
 253
 254         /* Register a home dir service for this user iff
 255
 256            (a) This is not a guest connection,
 257            (b) we have a home directory defined
 258            (c) there s not an existing static share by that name
 259
 260            If a share exists by this name (autoloaded or not) reuse it . */
 261
 262         vuser->homes_snum = -1;
 263
 264         if ( (!vuser->guest) && vuser->unix_homedir && *(vuser->unix_homedir))
 265         {
 266                 int servicenumber = lp_servicenumber(vuser->user.unix_name);
 267
 268                 if ( servicenumber == -1 ) {
 269                         DEBUG(3, ("Adding homes service for user '%s' using home directory: '%s'\n",
 270                                 vuser->user.unix_name, vuser->unix_homedir));
 271                         vuser->homes_snum = add_home_service(vuser->user.unix_name,
 272                                                 vuser->user.unix_name, vuser->unix_homedir);
 273                 } else {
 274                         DEBUG(3, ("Using static (or previously created) service for user '%s'; path = '%s'\n",
 275                                 vuser->user.unix_name, lp_pathname(servicenumber) ));
 276                         vuser->homes_snum = servicenumber;
 277                 }
 278         }
 279
 280         if (srv_is_signing_negotiated() && !vuser->guest && !srv_signing_started()) {
 281                 /* Try and turn on server signing on the first non-guest sessionsetup. */
 282                 srv_set_signing(vuser->session_key, response_blob);
 283         }
 284
 285         /* fill in the current_user_info struct */
 286         set_current_user_info( &vuser->user );
 287
 288
 289         return vuser->vuid;
 290 }
 291
 292 /****************************************************************************
 293  Add a name to the session users list.
 294 ****************************************************************************/
 295
 296 void add_session_user(const char *user)
 297 {
 298         fstring suser;
 299         struct passwd *passwd;
 300
 301         if (!(passwd = Get_Pwnam(user)))
 302                 return;
 303
 304         fstrcpy(suser,passwd->pw_name);
 305
 306         if(!*suser)
 307                 return;
 308
 309         if( session_userlist && in_list(suser,session_userlist,False) )
 310                 return;
 311
 312         if( !session_userlist || (strlen(suser) + strlen(session_userlist) + 2 >= len_session_userlist) ) {
 313                 char *newlist;
 314
 315                 if (len_session_userlist > 128 * PSTRING_LEN) {
 316                         DEBUG(3,("add_session_user: session userlist already too large.\n"));
 317                         return;
 318                 }
 319                 newlist = SMB_REALLOC( session_userlist, len_session_userlist + PSTRING_LEN );
 320                 if( newlist == NULL ) {
 321                         DEBUG(1,("Unable to resize session_userlist\n"));
 322                         return;
 323                 }
 324                 if (!session_userlist) {
 325                         *newlist = '\0';
 326                 }
 327                 session_userlist = newlist;
 328                 len_session_userlist += PSTRING_LEN;
 329         }
 330
 331         safe_strcat(session_userlist," ",len_session_userlist-1);
 332         safe_strcat(session_userlist,suser,len_session_userlist-1);
 333 }
 334
 335 /****************************************************************************
 336  Check if a username is valid.
 337 ****************************************************************************/
 338
 339 BOOL user_ok(const char *user,int snum, gid_t *groups, size_t n_groups)
 340 {
 341         char **valid, **invalid;
 342         BOOL ret;
 343
 344         valid = invalid = NULL;
 345         ret = True;
 346
 347         if (lp_invalid_users(snum)) {
 348                 str_list_copy(&invalid, lp_invalid_users(snum));
 349                 if (invalid && str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 350                         if ( invalid && str_list_sub_basic(invalid, current_user_info.smb_name) ) {
 351                                 ret = !user_in_list(user, (const char **)invalid, groups, n_groups);
 352                         }
 353                 }
 354         }
 355         if (invalid)
 356                 str_list_free (&invalid);
 357
 358         if (ret && lp_valid_users(snum)) {
 359                 str_list_copy(&valid, lp_valid_users(snum));
 360                 if ( valid && str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 361                         if ( valid && str_list_sub_basic(valid, current_user_info.smb_name) ) {
 362                                 ret = user_in_list(user, (const char **)valid, groups, n_groups);
 363                         }
 364                 }
 365         }
 366         if (valid)
 367                 str_list_free (&valid);
 368
 369         if (ret && lp_onlyuser(snum)) {
 370                 char **user_list = str_list_make (lp_username(snum), NULL);
 371                 if (user_list && str_list_substitute(user_list, "%S", lp_servicename(snum))) {
 372                         ret = user_in_list(user, (const char **)user_list, groups, n_groups);
 373                 }
 374                 if (user_list) str_list_free (&user_list);
 375         }
 376
 377         return(ret);
 378 }
 379
 380 /****************************************************************************
 381  Validate a group username entry. Return the username or NULL.
 382 ****************************************************************************/
 383
 384 static char *validate_group(char *group, DATA_BLOB password,int snum)
 385 {
 386 #ifdef HAVE_NETGROUP
 387         {
 388                 char *host, *user, *domain;
 389                 setnetgrent(group);
 390                 while (getnetgrent(&host, &user, &domain)) {
 391                         if (user) {
 392                                 if (user_ok(user, snum, NULL, 0) &&
 393                                     password_ok(user,password)) {
 394                                         endnetgrent();
 395                                         return(user);
 396                                 }
 397                         }
 398                 }
 399                 endnetgrent();
 400         }
 401 #endif
 402
 403 #ifdef HAVE_GETGRENT
 404         {
 405                 struct group *gptr;
 406                 setgrent();
 407                 while ((gptr = (struct group *)getgrent())) {
 408                         if (strequal(gptr->gr_name,group))
 409                                 break;
 410                 }
 411
 412                 /*
 413                  * As user_ok can recurse doing a getgrent(), we must
 414                  * copy the member list into a pstring on the stack before
 415                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 416                  */
 417
 418                 if (gptr) {
 419                         pstring member_list;
 420                         char *member;
 421                         size_t copied_len = 0;
 422                         int i;
 423
 424                         *member_list = '\0';
 425                         member = member_list;
 426
 427                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 428                                 size_t member_len = strlen(gptr->gr_mem[i]) + 1;
 429                                 if( copied_len + member_len < sizeof(pstring)) {
 430
 431                                         DEBUG(10,("validate_group: = gr_mem = %s\n", gptr->gr_mem[i]));
 432
 433                                         safe_strcpy(member, gptr->gr_mem[i], sizeof(pstring) - copied_len - 1);
 434                                         copied_len += member_len;
 435                                         member += copied_len;
 436                                 } else {
 437                                         *member = '\0';
 438                                 }
 439                         }
 440
 441                         endgrent();
 442
 443                         member = member_list;
 444                         while (*member) {
 445                                 static fstring name;
 446                                 fstrcpy(name,member);
 447                                 if (user_ok(name,snum, NULL, 0) &&
 448                                     password_ok(name,password)) {
 449                                         endgrent();
 450                                         return(&name[0]);
 451                                 }
 452
 453                                 DEBUG(10,("validate_group = member = %s\n", member));
 454
 455                                 member += strlen(member) + 1;
 456                         }
 457                 } else {
 458                         endgrent();
 459                         return NULL;
 460                 }
 461         }
 462 #endif
 463         return(NULL);
 464 }
 465
 466 /****************************************************************************
 467  Check for authority to login to a service with a given username/password.
 468  Note this is *NOT* used when logging on using sessionsetup_and_X.
 469 ****************************************************************************/
 470
 471 BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 472                      BOOL *guest)
 473 {
 474         BOOL ok = False;
 475
 476 #ifdef DEBUG_PASSWORD
 477         DEBUG(100,("authorise_login: checking authorisation on user=%s pass=%s\n",
 478                    user,password.data));
 479 #endif
 480
 481         *guest = False;
 482
 483         /* there are several possibilities:
 484                 1) login as the given user with given password
 485                 2) login as a previously registered username with the given password
 486                 3) login as a session list username with the given password
 487                 4) login as a previously validated user/password pair
 488                 5) login as the "user =" user with given password
 489                 6) login as the "user =" user with no password (guest connection)
 490                 7) login as guest user with no password
 491
 492                 if the service is guest_only then steps 1 to 5 are skipped
 493         */
 494
 495         /* now check the list of session users */
 496         if (!ok) {
 497                 char *auser;
 498                 char *user_list = NULL;
 499
 500                 if ( session_userlist )
 501                         user_list = SMB_STRDUP(session_userlist);
 502                 else
 503                         user_list = SMB_STRDUP("");
 504
 505                 if (!user_list)
 506                         return(False);
 507
 508                 for (auser=strtok(user_list,LIST_SEP); !ok && auser;
 509                      auser = strtok(NULL,LIST_SEP)) {
 510                         fstring user2;
 511                         fstrcpy(user2,auser);
 512                         if (!user_ok(user2,snum, NULL, 0))
 513                                 continue;
 514
 515                         if (password_ok(user2,password)) {
 516                                 ok = True;
 517                                 fstrcpy(user,user2);
 518                                 DEBUG(3,("authorise_login: ACCEPTED: session list username (%s) \
 519 and given password ok\n", user));
 520                         }
 521                 }
 522
 523                 SAFE_FREE(user_list);
 524         }
 525
 526         /* check the user= fields and the given password */
 527         if (!ok && lp_username(snum)) {
 528                 char *auser;
 529                 pstring user_list;
 530                 pstrcpy(user_list,lp_username(snum));
 531
 532                 pstring_sub(user_list,"%S",lp_servicename(snum));
 533
 534                 for (auser=strtok(user_list,LIST_SEP); auser && !ok;
 535                      auser = strtok(NULL,LIST_SEP)) {
 536                         if (*auser == '@') {
 537                                 auser = validate_group(auser+1,password,snum);
 538                                 if (auser) {
 539                                         ok = True;
 540                                         fstrcpy(user,auser);
 541                                         DEBUG(3,("authorise_login: ACCEPTED: group username \
 542 and given password ok (%s)\n", user));
 543                                 }
 544                         } else {
 545                                 fstring user2;
 546                                 fstrcpy(user2,auser);
 547                                 if (user_ok(user2,snum, NULL, 0) && password_ok(user2,password)) {
 548                                         ok = True;
 549                                         fstrcpy(user,user2);
 550                                         DEBUG(3,("authorise_login: ACCEPTED: user list username \
 551 and given password ok (%s)\n", user));
 552                                 }
 553                         }
 554                 }
 555         }
 556
 557         /* check for a normal guest connection */
 558         if (!ok && GUEST_OK(snum)) {
 559                 fstring guestname;
 560                 fstrcpy(guestname,lp_guestaccount());
 561                 if (Get_Pwnam(guestname)) {
 562                         fstrcpy(user,guestname);
 563                         ok = True;
 564                         DEBUG(3,("authorise_login: ACCEPTED: guest account and guest ok (%s)\n",
 565                                         user));
 566                 } else {
 567                         DEBUG(0,("authorise_login: Invalid guest account %s??\n",guestname));
 568                 }
 569                 *guest = True;
 570         }
 571
 572         if (ok && !user_ok(user, snum, NULL, 0)) {
 573                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 574                 ok = False;
 575         }
 576
 577         return(ok);
 578 }