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 pstring session_users="";
  25
  26 /* this holds info on user ids that are already validated for this VC */
  27 static user_struct *validated_users;
  28 static int next_vuid = VUID_OFFSET;
  29 static int num_validated_vuids;
  30
  31 extern userdom_struct current_user_info;
  32
  33
  34 /****************************************************************************
  35  Check if a uid has been validated, and return an pointer to the user_struct
  36  if it has. NULL if not. vuid is biased by an offset. This allows us to
  37  tell random client vuid's (normally zero) from valid vuids.
  38 ****************************************************************************/
  39
  40 user_struct *get_valid_user_struct(uint16 vuid)
  41 {
  42         user_struct *usp;
  43         int count=0;
  44
  45         if (vuid == UID_FIELD_INVALID)
  46                 return NULL;
  47
  48         for (usp=validated_users;usp;usp=usp->next,count++) {
  49                 if (vuid == usp->vuid) {
  50                         if (count > 10) {
  51                                 DLIST_PROMOTE(validated_users, usp);
  52                         }
  53                         return usp;
  54                 }
  55         }
  56
  57         return NULL;
  58 }
  59
  60 /****************************************************************************
  61  Invalidate a uid.
  62 ****************************************************************************/
  63
  64 void invalidate_vuid(uint16 vuid)
  65 {
  66         user_struct *vuser = get_valid_user_struct(vuid);
  67
  68         if (vuser == NULL)
  69                 return;
  70
  71         SAFE_FREE(vuser->homedir);
  72         SAFE_FREE(vuser->unix_homedir);
  73         SAFE_FREE(vuser->logon_script);
  74
  75         session_yield(vuser);
  76         SAFE_FREE(vuser->session_keystr);
  77
  78         free_server_info(&vuser->server_info);
  79
  80         data_blob_free(&vuser->session_key);
  81
  82         DLIST_REMOVE(validated_users, vuser);
  83
  84         /* clear the vuid from the 'cache' on each connection, and
  85            from the vuid 'owner' of connections */
  86         conn_clear_vuid_cache(vuid);
  87
  88         SAFE_FREE(vuser->groups);
  89         delete_nt_token(&vuser->nt_user_token);
  90         SAFE_FREE(vuser);
  91         num_validated_vuids--;
  92 }
  93
  94 /****************************************************************************
  95  Invalidate all vuid entries for this process.
  96 ****************************************************************************/
  97
  98 void invalidate_all_vuids(void)
  99 {
 100         user_struct *usp, *next=NULL;
 101
 102         for (usp=validated_users;usp;usp=next) {
 103                 next = usp->next;
 104
 105                 invalidate_vuid(usp->vuid);
 106         }
 107 }
 108
 109 /**
 110  *  register that a valid login has been performed, establish 'session'.
 111  *  @param server_info The token returned from the authentication process.
 112  *   (now 'owned' by register_vuid)
 113  *
 114  *  @param session_key The User session key for the login session (now also 'owned' by register_vuid)
 115  *
 116  *  @param respose_blob The NT challenge-response, if available.  (May be freed after this call)
 117  *
 118  *  @param smb_name The untranslated name of the user
 119  *
 120  *  @return Newly allocated vuid, biased by an offset. (This allows us to
 121  *   tell random client vuid's (normally zero) from valid vuids.)
 122  *
 123  */
 124
 125 int register_vuid(auth_serversupplied_info *server_info, DATA_BLOB session_key, DATA_BLOB response_blob, const char *smb_name)
 126 {
 127         user_struct *vuser = NULL;
 128
 129         /* Ensure no vuid gets registered in share level security. */
 130         if(lp_security() == SEC_SHARE) {
 131                 data_blob_free(&session_key);
 132                 return UID_FIELD_INVALID;
 133         }
 134
 135         /* Limit allowed vuids to 16bits - VUID_OFFSET. */
 136         if (num_validated_vuids >= 0xFFFF-VUID_OFFSET) {
 137                 data_blob_free(&session_key);
 138                 return UID_FIELD_INVALID;
 139         }
 140
 141         if((vuser = (user_struct *)malloc( sizeof(user_struct) )) == NULL) {
 142                 DEBUG(0,("Failed to malloc users struct!\n"));
 143                 data_blob_free(&session_key);
 144                 return UID_FIELD_INVALID;
 145         }
 146
 147         ZERO_STRUCTP(vuser);
 148
 149         /* Allocate a free vuid. Yes this is a linear search... :-) */
 150         while( get_valid_user_struct(next_vuid) != NULL ) {
 151                 next_vuid++;
 152                 /* Check for vuid wrap. */
 153                 if (next_vuid == UID_FIELD_INVALID)
 154                         next_vuid = VUID_OFFSET;
 155         }
 156
 157         DEBUG(10,("register_vuid: allocated vuid = %u\n", (unsigned int)next_vuid ));
 158
 159         vuser->vuid = next_vuid;
 160
 161         /* the next functions should be done by a SID mapping system (SMS) as
 162          * the new real sam db won't have reference to unix uids or gids
 163          */
 164
 165         vuser->uid = server_info->uid;
 166         vuser->gid = server_info->gid;
 167
 168         vuser->n_groups = server_info->n_groups;
 169         if (vuser->n_groups) {
 170                 if (!(vuser->groups = memdup(server_info->groups, sizeof(gid_t) * vuser->n_groups))) {
 171                         DEBUG(0,("register_vuid: failed to memdup vuser->groups\n"));
 172                         data_blob_free(&session_key);
 173                         free(vuser);
 174                         free_server_info(&server_info);
 175                         return UID_FIELD_INVALID;
 176                 }
 177         }
 178
 179         vuser->guest = server_info->guest;
 180         fstrcpy(vuser->user.unix_name, server_info->unix_name);
 181
 182         /* This is a potentially untrusted username */
 183         alpha_strcpy(vuser->user.smb_name, smb_name, ". _-$", sizeof(vuser->user.smb_name));
 184
 185         fstrcpy(vuser->user.domain, pdb_get_domain(server_info->sam_account));
 186         fstrcpy(vuser->user.full_name, pdb_get_fullname(server_info->sam_account));
 187
 188         {
 189                 /* Keep the homedir handy */
 190                 const char *homedir = pdb_get_homedir(server_info->sam_account);
 191                 const char *logon_script = pdb_get_logon_script(server_info->sam_account);
 192
 193                 if (!IS_SAM_DEFAULT(server_info->sam_account, PDB_UNIXHOMEDIR)) {
 194                         const char *unix_homedir = pdb_get_unix_homedir(server_info->sam_account);
 195                         if (unix_homedir) {
 196                                 vuser->unix_homedir = smb_xstrdup(unix_homedir);
 197                         }
 198                 } else {
 199                         struct passwd *passwd = getpwnam_alloc(vuser->user.unix_name);
 200                         if (passwd) {
 201                                 vuser->unix_homedir = smb_xstrdup(passwd->pw_dir);
 202                                 passwd_free(&passwd);
 203                         }
 204                 }
 205
 206                 if (homedir) {
 207                         vuser->homedir = smb_xstrdup(homedir);
 208                 }
 209                 if (logon_script) {
 210                         vuser->logon_script = smb_xstrdup(logon_script);
 211                 }
 212         }
 213
 214         vuser->session_key = session_key;
 215
 216         DEBUG(10,("register_vuid: (%u,%u) %s %s %s guest=%d\n",
 217                   (unsigned int)vuser->uid,
 218                   (unsigned int)vuser->gid,
 219                   vuser->user.unix_name, vuser->user.smb_name, vuser->user.domain, vuser->guest ));
 220
 221         DEBUG(3, ("User name: %s\tReal name: %s\n",vuser->user.unix_name,vuser->user.full_name));
 222
 223         if (server_info->ptok) {
 224                 vuser->nt_user_token = dup_nt_token(server_info->ptok);
 225         } else {
 226                 DEBUG(1, ("server_info does not contain a user_token - cannot continue\n"));
 227                 free_server_info(&server_info);
 228                 data_blob_free(&session_key);
 229                 SAFE_FREE(vuser->homedir);
 230                 SAFE_FREE(vuser->unix_homedir);
 231                 SAFE_FREE(vuser->logon_script);
 232
 233                 SAFE_FREE(vuser);
 234                 return UID_FIELD_INVALID;
 235         }
 236
 237         /* use this to keep tabs on all our info from the authentication */
 238         vuser->server_info = server_info;
 239
 240         DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",(int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 241
 242         next_vuid++;
 243         num_validated_vuids++;
 244
 245         DLIST_ADD(validated_users, vuser);
 246
 247         if (!session_claim(vuser)) {
 248                 DEBUG(1,("Failed to claim session for vuid=%d\n", vuser->vuid));
 249                 invalidate_vuid(vuser->vuid);
 250                 return -1;
 251         }
 252
 253         /* Register a home dir service for this user iff
 254            (a) This is not a guest connection,
 255            (b) we have a home directory defined, and
 256            (c) there s not an existing static share by that name */
 257
 258         if ( (!vuser->guest)
 259                 && vuser->unix_homedir
 260                 && *(vuser->unix_homedir)
 261                 && (lp_servicenumber(vuser->user.unix_name) == -1) )
 262         {
 263                         DEBUG(3, ("Adding/updating homes service for user '%s' using home directory: '%s'\n",
 264                                 vuser->user.unix_name, vuser->unix_homedir));
 265
 266                         vuser->homes_snum = add_home_service(vuser->user.unix_name,
 267                                 vuser->user.unix_name, vuser->unix_homedir);
 268         } else {
 269                 vuser->homes_snum = -1;
 270         }
 271
 272         if (lp_server_signing() && !vuser->guest && !srv_is_signing_active()) {
 273                 /* Try and turn on server signing on the first non-guest sessionsetup. */
 274                 srv_set_signing(vuser->session_key, response_blob);
 275         }
 276
 277         return vuser->vuid;
 278 }
 279
 280 /****************************************************************************
 281  Add a name to the session users list.
 282 ****************************************************************************/
 283
 284 void add_session_user(const char *user)
 285 {
 286         fstring suser;
 287         struct passwd *passwd;
 288
 289         if (!(passwd = Get_Pwnam(user)))
 290                 return;
 291
 292         fstrcpy(suser,passwd->pw_name);
 293
 294         if (suser && *suser && !in_list(suser,session_users,False)) {
 295                 if (strlen(suser) + strlen(session_users) + 2 >= sizeof(pstring)) {
 296                         DEBUG(1,("Too many session users??\n"));
 297                 } else {
 298                         pstrcat(session_users," ");
 299                         pstrcat(session_users,suser);
 300                 }
 301         }
 302 }
 303
 304 /****************************************************************************
 305  Check if a username is valid.
 306 ****************************************************************************/
 307
 308 BOOL user_ok(const char *user,int snum, gid_t *groups, size_t n_groups)
 309 {
 310         char **valid, **invalid;
 311         BOOL ret;
 312
 313         valid = invalid = NULL;
 314         ret = True;
 315
 316         if (lp_invalid_users(snum)) {
 317                 str_list_copy(&invalid, lp_invalid_users(snum));
 318                 if (invalid && str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 319                         if ( invalid && str_list_sub_basic(invalid, current_user_info.smb_name) ) {
 320                                 ret = !user_in_list(user, (const char **)invalid, groups, n_groups);
 321                         }
 322                 }
 323         }
 324         if (invalid)
 325                 str_list_free (&invalid);
 326
 327         if (ret && lp_valid_users(snum)) {
 328                 str_list_copy(&valid, lp_valid_users(snum));
 329                 if ( valid && str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 330                         if ( valid && str_list_sub_basic(valid, current_user_info.smb_name) ) {
 331                                 ret = user_in_list(user, (const char **)valid, groups, n_groups);
 332                         }
 333                 }
 334         }
 335         if (valid)
 336                 str_list_free (&valid);
 337
 338         if (ret && lp_onlyuser(snum)) {
 339                 char **user_list = str_list_make (lp_username(snum), NULL);
 340                 if (user_list && str_list_substitute(user_list, "%S", lp_servicename(snum))) {
 341                         ret = user_in_list(user, (const char **)user_list, groups, n_groups);
 342                 }
 343                 if (user_list) str_list_free (&user_list);
 344         }
 345
 346         return(ret);
 347 }
 348
 349 /****************************************************************************
 350  Validate a group username entry. Return the username or NULL.
 351 ****************************************************************************/
 352
 353 static char *validate_group(char *group, DATA_BLOB password,int snum)
 354 {
 355 #ifdef HAVE_NETGROUP
 356         {
 357                 char *host, *user, *domain;
 358                 setnetgrent(group);
 359                 while (getnetgrent(&host, &user, &domain)) {
 360                         if (user) {
 361                                 if (user_ok(user, snum, NULL, 0) &&
 362                                     password_ok(user,password)) {
 363                                         endnetgrent();
 364                                         return(user);
 365                                 }
 366                         }
 367                 }
 368                 endnetgrent();
 369         }
 370 #endif
 371
 372 #ifdef HAVE_GETGRENT
 373         {
 374                 struct group *gptr;
 375                 setgrent();
 376                 while ((gptr = (struct group *)getgrent())) {
 377                         if (strequal(gptr->gr_name,group))
 378                                 break;
 379                 }
 380
 381                 /*
 382                  * As user_ok can recurse doing a getgrent(), we must
 383                  * copy the member list into a pstring on the stack before
 384                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 385                  */
 386
 387                 if (gptr) {
 388                         pstring member_list;
 389                         char *member;
 390                         size_t copied_len = 0;
 391                         int i;
 392
 393                         *member_list = '\0';
 394                         member = member_list;
 395
 396                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 397                                 size_t member_len = strlen(gptr->gr_mem[i]) + 1;
 398                                 if( copied_len + member_len < sizeof(pstring)) {
 399
 400                                         DEBUG(10,("validate_group: = gr_mem = %s\n", gptr->gr_mem[i]));
 401
 402                                         safe_strcpy(member, gptr->gr_mem[i], sizeof(pstring) - copied_len - 1);
 403                                         copied_len += member_len;
 404                                         member += copied_len;
 405                                 } else {
 406                                         *member = '\0';
 407                                 }
 408                         }
 409
 410                         endgrent();
 411
 412                         member = member_list;
 413                         while (*member) {
 414                                 static fstring name;
 415                                 fstrcpy(name,member);
 416                                 if (user_ok(name,snum, NULL, 0) &&
 417                                     password_ok(name,password)) {
 418                                         endgrent();
 419                                         return(&name[0]);
 420                                 }
 421
 422                                 DEBUG(10,("validate_group = member = %s\n", member));
 423
 424                                 member += strlen(member) + 1;
 425                         }
 426                 } else {
 427                         endgrent();
 428                         return NULL;
 429                 }
 430         }
 431 #endif
 432         return(NULL);
 433 }
 434
 435 /****************************************************************************
 436  Check for authority to login to a service with a given username/password.
 437  Note this is *NOT* used when logging on using sessionsetup_and_X.
 438 ****************************************************************************/
 439
 440 BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 441                      BOOL *guest)
 442 {
 443         BOOL ok = False;
 444
 445 #if DEBUG_PASSWORD
 446         DEBUG(100,("authorise_login: checking authorisation on user=%s pass=%s\n",
 447                    user,password.data));
 448 #endif
 449
 450         *guest = False;
 451
 452         /* there are several possibilities:
 453                 1) login as the given user with given password
 454                 2) login as a previously registered username with the given password
 455                 3) login as a session list username with the given password
 456                 4) login as a previously validated user/password pair
 457                 5) login as the "user =" user with given password
 458                 6) login as the "user =" user with no password (guest connection)
 459                 7) login as guest user with no password
 460
 461                 if the service is guest_only then steps 1 to 5 are skipped
 462         */
 463
 464         /* now check the list of session users */
 465         if (!ok) {
 466                 char *auser;
 467                 char *user_list = strdup(session_users);
 468                 if (!user_list)
 469                         return(False);
 470
 471                 for (auser=strtok(user_list,LIST_SEP); !ok && auser;
 472                      auser = strtok(NULL,LIST_SEP)) {
 473                         fstring user2;
 474                         fstrcpy(user2,auser);
 475                         if (!user_ok(user2,snum, NULL, 0))
 476                                 continue;
 477
 478                         if (password_ok(user2,password)) {
 479                                 ok = True;
 480                                 fstrcpy(user,user2);
 481                                 DEBUG(3,("authorise_login: ACCEPTED: session list username (%s) \
 482 and given password ok\n", user));
 483                         }
 484                 }
 485
 486                 SAFE_FREE(user_list);
 487         }
 488
 489         /* check the user= fields and the given password */
 490         if (!ok && lp_username(snum)) {
 491                 char *auser;
 492                 pstring user_list;
 493                 pstrcpy(user_list,lp_username(snum));
 494
 495                 pstring_sub(user_list,"%S",lp_servicename(snum));
 496
 497                 for (auser=strtok(user_list,LIST_SEP); auser && !ok;
 498                      auser = strtok(NULL,LIST_SEP)) {
 499                         if (*auser == '@') {
 500                                 auser = validate_group(auser+1,password,snum);
 501                                 if (auser) {
 502                                         ok = True;
 503                                         fstrcpy(user,auser);
 504                                         DEBUG(3,("authorise_login: ACCEPTED: group username \
 505 and given password ok (%s)\n", user));
 506                                 }
 507                         } else {
 508                                 fstring user2;
 509                                 fstrcpy(user2,auser);
 510                                 if (user_ok(user2,snum, NULL, 0) && password_ok(user2,password)) {
 511                                         ok = True;
 512                                         fstrcpy(user,user2);
 513                                         DEBUG(3,("authorise_login: ACCEPTED: user list username \
 514 and given password ok (%s)\n", user));
 515                                 }
 516                         }
 517                 }
 518         }
 519
 520         /* check for a normal guest connection */
 521         if (!ok && GUEST_OK(snum)) {
 522                 fstring guestname;
 523                 fstrcpy(guestname,lp_guestaccount());
 524                 if (Get_Pwnam(guestname)) {
 525                         fstrcpy(user,guestname);
 526                         ok = True;
 527                         DEBUG(3,("authorise_login: ACCEPTED: guest account and guest ok (%s)\n",
 528                                         user));
 529                 } else {
 530                         DEBUG(0,("authorise_login: Invalid guest account %s??\n",guestname));
 531                 }
 532                 *guest = True;
 533         }
 534
 535         if (ok && !user_ok(user, snum, NULL, 0)) {
 536                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 537                 ok = False;
 538         }
 539
 540         return(ok);
 541 }