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         destroy_privilege(&vuser->privs);
  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 = (user_struct *)malloc( sizeof(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         if (server_info->privs) {
 239                 init_privilege(&(vuser->privs));
 240                 dup_priv_set(vuser->privs, server_info->privs);
 241         }
 242
 243         /* use this to keep tabs on all our info from the authentication */
 244         vuser->server_info = server_info;
 245
 246         DEBUG(3,("UNIX uid %d is UNIX user %s, and will be vuid %u\n",(int)vuser->uid,vuser->user.unix_name, vuser->vuid));
 247
 248         next_vuid++;
 249         num_validated_vuids++;
 250
 251         DLIST_ADD(validated_users, vuser);
 252
 253         if (!session_claim(vuser)) {
 254                 DEBUG(1,("Failed to claim session for vuid=%d\n", vuser->vuid));
 255                 invalidate_vuid(vuser->vuid);
 256                 return -1;
 257         }
 258
 259         /* Register a home dir service for this user iff
 260            (a) This is not a guest connection,
 261            (b) we have a home directory defined, and
 262            (c) there s not an existing static share by that name */
 263
 264         if ( (!vuser->guest)
 265                 && vuser->unix_homedir
 266                 && *(vuser->unix_homedir)
 267                 && (lp_servicenumber(vuser->user.unix_name) == -1) )
 268         {
 269                         DEBUG(3, ("Adding/updating homes service for user '%s' using home directory: '%s'\n",
 270                                 vuser->user.unix_name, vuser->unix_homedir));
 271
 272                         vuser->homes_snum = add_home_service(vuser->user.unix_name,
 273                                 vuser->user.unix_name, vuser->unix_homedir);
 274         } else {
 275                 vuser->homes_snum = -1;
 276         }
 277
 278         if (srv_is_signing_negotiated() && !vuser->guest && !srv_signing_started()) {
 279                 /* Try and turn on server signing on the first non-guest sessionsetup. */
 280                 srv_set_signing(vuser->session_key, response_blob);
 281         }
 282
 283         return vuser->vuid;
 284 }
 285
 286 /****************************************************************************
 287  Add a name to the session users list.
 288 ****************************************************************************/
 289
 290 void add_session_user(const char *user)
 291 {
 292         fstring suser;
 293         struct passwd *passwd;
 294
 295         if (!(passwd = Get_Pwnam(user)))
 296                 return;
 297
 298         fstrcpy(suser,passwd->pw_name);
 299
 300         if (suser && *suser && !in_list(suser,session_users,False)) {
 301                 if (strlen(suser) + strlen(session_users) + 2 >= sizeof(pstring)) {
 302                         DEBUG(1,("Too many session users??\n"));
 303                 } else {
 304                         pstrcat(session_users," ");
 305                         pstrcat(session_users,suser);
 306                 }
 307         }
 308 }
 309
 310 /****************************************************************************
 311  Check if a username is valid.
 312 ****************************************************************************/
 313
 314 BOOL user_ok(const char *user,int snum, gid_t *groups, size_t n_groups)
 315 {
 316         char **valid, **invalid;
 317         BOOL ret;
 318
 319         valid = invalid = NULL;
 320         ret = True;
 321
 322         if (lp_invalid_users(snum)) {
 323                 str_list_copy(&invalid, lp_invalid_users(snum));
 324                 if (invalid && str_list_substitute(invalid, "%S", lp_servicename(snum))) {
 325                         if ( invalid && str_list_sub_basic(invalid, current_user_info.smb_name) ) {
 326                                 ret = !user_in_list(user, (const char **)invalid, groups, n_groups);
 327                         }
 328                 }
 329         }
 330         if (invalid)
 331                 str_list_free (&invalid);
 332
 333         if (ret && lp_valid_users(snum)) {
 334                 str_list_copy(&valid, lp_valid_users(snum));
 335                 if ( valid && str_list_substitute(valid, "%S", lp_servicename(snum)) ) {
 336                         if ( valid && str_list_sub_basic(valid, current_user_info.smb_name) ) {
 337                                 ret = user_in_list(user, (const char **)valid, groups, n_groups);
 338                         }
 339                 }
 340         }
 341         if (valid)
 342                 str_list_free (&valid);
 343
 344         if (ret && lp_onlyuser(snum)) {
 345                 char **user_list = str_list_make (lp_username(snum), NULL);
 346                 if (user_list && str_list_substitute(user_list, "%S", lp_servicename(snum))) {
 347                         ret = user_in_list(user, (const char **)user_list, groups, n_groups);
 348                 }
 349                 if (user_list) str_list_free (&user_list);
 350         }
 351
 352         return(ret);
 353 }
 354
 355 /****************************************************************************
 356  Validate a group username entry. Return the username or NULL.
 357 ****************************************************************************/
 358
 359 static char *validate_group(char *group, DATA_BLOB password,int snum)
 360 {
 361 #ifdef HAVE_NETGROUP
 362         {
 363                 char *host, *user, *domain;
 364                 setnetgrent(group);
 365                 while (getnetgrent(&host, &user, &domain)) {
 366                         if (user) {
 367                                 if (user_ok(user, snum, NULL, 0) &&
 368                                     password_ok(user,password)) {
 369                                         endnetgrent();
 370                                         return(user);
 371                                 }
 372                         }
 373                 }
 374                 endnetgrent();
 375         }
 376 #endif
 377
 378 #ifdef HAVE_GETGRENT
 379         {
 380                 struct group *gptr;
 381                 setgrent();
 382                 while ((gptr = (struct group *)getgrent())) {
 383                         if (strequal(gptr->gr_name,group))
 384                                 break;
 385                 }
 386
 387                 /*
 388                  * As user_ok can recurse doing a getgrent(), we must
 389                  * copy the member list into a pstring on the stack before
 390                  * use. Bug pointed out by leon@eatworms.swmed.edu.
 391                  */
 392
 393                 if (gptr) {
 394                         pstring member_list;
 395                         char *member;
 396                         size_t copied_len = 0;
 397                         int i;
 398
 399                         *member_list = '\0';
 400                         member = member_list;
 401
 402                         for(i = 0; gptr->gr_mem && gptr->gr_mem[i]; i++) {
 403                                 size_t member_len = strlen(gptr->gr_mem[i]) + 1;
 404                                 if( copied_len + member_len < sizeof(pstring)) {
 405
 406                                         DEBUG(10,("validate_group: = gr_mem = %s\n", gptr->gr_mem[i]));
 407
 408                                         safe_strcpy(member, gptr->gr_mem[i], sizeof(pstring) - copied_len - 1);
 409                                         copied_len += member_len;
 410                                         member += copied_len;
 411                                 } else {
 412                                         *member = '\0';
 413                                 }
 414                         }
 415
 416                         endgrent();
 417
 418                         member = member_list;
 419                         while (*member) {
 420                                 static fstring name;
 421                                 fstrcpy(name,member);
 422                                 if (user_ok(name,snum, NULL, 0) &&
 423                                     password_ok(name,password)) {
 424                                         endgrent();
 425                                         return(&name[0]);
 426                                 }
 427
 428                                 DEBUG(10,("validate_group = member = %s\n", member));
 429
 430                                 member += strlen(member) + 1;
 431                         }
 432                 } else {
 433                         endgrent();
 434                         return NULL;
 435                 }
 436         }
 437 #endif
 438         return(NULL);
 439 }
 440
 441 /****************************************************************************
 442  Check for authority to login to a service with a given username/password.
 443  Note this is *NOT* used when logging on using sessionsetup_and_X.
 444 ****************************************************************************/
 445
 446 BOOL authorise_login(int snum, fstring user, DATA_BLOB password,
 447                      BOOL *guest)
 448 {
 449         BOOL ok = False;
 450
 451 #if DEBUG_PASSWORD
 452         DEBUG(100,("authorise_login: checking authorisation on user=%s pass=%s\n",
 453                    user,password.data));
 454 #endif
 455
 456         *guest = False;
 457
 458         /* there are several possibilities:
 459                 1) login as the given user with given password
 460                 2) login as a previously registered username with the given password
 461                 3) login as a session list username with the given password
 462                 4) login as a previously validated user/password pair
 463                 5) login as the "user =" user with given password
 464                 6) login as the "user =" user with no password (guest connection)
 465                 7) login as guest user with no password
 466
 467                 if the service is guest_only then steps 1 to 5 are skipped
 468         */
 469
 470         /* now check the list of session users */
 471         if (!ok) {
 472                 char *auser;
 473                 char *user_list = strdup(session_users);
 474                 if (!user_list)
 475                         return(False);
 476
 477                 for (auser=strtok(user_list,LIST_SEP); !ok && auser;
 478                      auser = strtok(NULL,LIST_SEP)) {
 479                         fstring user2;
 480                         fstrcpy(user2,auser);
 481                         if (!user_ok(user2,snum, NULL, 0))
 482                                 continue;
 483
 484                         if (password_ok(user2,password)) {
 485                                 ok = True;
 486                                 fstrcpy(user,user2);
 487                                 DEBUG(3,("authorise_login: ACCEPTED: session list username (%s) \
 488 and given password ok\n", user));
 489                         }
 490                 }
 491
 492                 SAFE_FREE(user_list);
 493         }
 494
 495         /* check the user= fields and the given password */
 496         if (!ok && lp_username(snum)) {
 497                 char *auser;
 498                 pstring user_list;
 499                 pstrcpy(user_list,lp_username(snum));
 500
 501                 pstring_sub(user_list,"%S",lp_servicename(snum));
 502
 503                 for (auser=strtok(user_list,LIST_SEP); auser && !ok;
 504                      auser = strtok(NULL,LIST_SEP)) {
 505                         if (*auser == '@') {
 506                                 auser = validate_group(auser+1,password,snum);
 507                                 if (auser) {
 508                                         ok = True;
 509                                         fstrcpy(user,auser);
 510                                         DEBUG(3,("authorise_login: ACCEPTED: group username \
 511 and given password ok (%s)\n", user));
 512                                 }
 513                         } else {
 514                                 fstring user2;
 515                                 fstrcpy(user2,auser);
 516                                 if (user_ok(user2,snum, NULL, 0) && password_ok(user2,password)) {
 517                                         ok = True;
 518                                         fstrcpy(user,user2);
 519                                         DEBUG(3,("authorise_login: ACCEPTED: user list username \
 520 and given password ok (%s)\n", user));
 521                                 }
 522                         }
 523                 }
 524         }
 525
 526         /* check for a normal guest connection */
 527         if (!ok && GUEST_OK(snum)) {
 528                 fstring guestname;
 529                 fstrcpy(guestname,lp_guestaccount());
 530                 if (Get_Pwnam(guestname)) {
 531                         fstrcpy(user,guestname);
 532                         ok = True;
 533                         DEBUG(3,("authorise_login: ACCEPTED: guest account and guest ok (%s)\n",
 534                                         user));
 535                 } else {
 536                         DEBUG(0,("authorise_login: Invalid guest account %s??\n",guestname));
 537                 }
 538                 *guest = True;
 539         }
 540
 541         if (ok && !user_ok(user, snum, NULL, 0)) {
 542                 DEBUG(0,("authorise_login: rejected invalid user %s\n",user));
 543                 ok = False;
 544         }
 545
 546         return(ok);
 547 }