source3/smbd/uid.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    uid/user handling
   5    Copyright (C) Andrew Tridgell 1992-1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 /* what user is current? */
  25 extern struct current_user current_user;
  26
  27 /****************************************************************************
  28  Become the guest user without changing the security context stack.
  29 ****************************************************************************/
  30
  31 BOOL change_to_guest(void)
  32 {
  33         static struct passwd *pass=NULL;
  34         static uid_t guest_uid = (uid_t)-1;
  35         static gid_t guest_gid = (gid_t)-1;
  36         static fstring guest_name;
  37
  38         if (!pass) {
  39                 pass = Get_Pwnam(lp_guestaccount(-1),True);
  40                 if (!pass)
  41                         return(False);
  42                 guest_uid = pass->pw_uid;
  43                 guest_gid = pass->pw_gid;
  44                 fstrcpy(guest_name, pass->pw_name);
  45         }
  46
  47 #ifdef AIX
  48         /* MWW: From AIX FAQ patch to WU-ftpd: call initgroups before
  49            setting IDs */
  50         initgroups(guest_name, guest_gid);
  51 #endif
  52
  53         set_sec_ctx(guest_uid, guest_gid, 0, NULL, NULL);
  54
  55         current_user.conn = NULL;
  56         current_user.vuid = UID_FIELD_INVALID;
  57
  58         return True;
  59 }
  60
  61 /*******************************************************************
  62  Check if a username is OK.
  63 ********************************************************************/
  64
  65 static BOOL check_user_ok(connection_struct *conn, user_struct *vuser,int snum)
  66 {
  67         int i;
  68         for (i=0;i<conn->uid_cache.entries;i++)
  69                 if (conn->uid_cache.list[i] == vuser->uid)
  70                         return(True);
  71
  72         if (!user_ok(vuser->user.unix_name,snum))
  73                 return(False);
  74
  75         i = conn->uid_cache.entries % UID_CACHE_SIZE;
  76         conn->uid_cache.list[i] = vuser->uid;
  77
  78         if (conn->uid_cache.entries < UID_CACHE_SIZE)
  79                 conn->uid_cache.entries++;
  80
  81         return(True);
  82 }
  83
  84 /****************************************************************************
  85  Become the user of a connection number without changing the security context
  86  stack, but modify the currnet_user entries.
  87 ****************************************************************************/
  88
  89 BOOL change_to_user(connection_struct *conn, uint16 vuid)
  90 {
  91         user_struct *vuser = get_valid_user_struct(vuid);
  92         int snum;
  93         gid_t gid;
  94         uid_t uid;
  95         char group_c;
  96         BOOL must_free_token = False;
  97         NT_USER_TOKEN *token = NULL;
  98
  99         if (!conn) {
 100                 DEBUG(2,("change_to_user: Connection not open\n"));
 101                 return(False);
 102         }
 103
 104         /*
 105          * We need a separate check in security=share mode due to vuid
 106          * always being UID_FIELD_INVALID. If we don't do this then
 107          * in share mode security we are *always* changing uid's between
 108          * SMB's - this hurts performance - Badly.
 109          */
 110
 111         if((lp_security() == SEC_SHARE) && (current_user.conn == conn) &&
 112            (current_user.uid == conn->uid)) {
 113                 DEBUG(4,("change_to_user: Skipping user change - already user\n"));
 114                 return(True);
 115         } else if ((current_user.conn == conn) &&
 116                    (vuser != 0) && (current_user.vuid == vuid) &&
 117                    (current_user.uid == vuser->uid)) {
 118                 DEBUG(4,("change_to_user: Skipping user change - already user\n"));
 119                 return(True);
 120         }
 121
 122         snum = SNUM(conn);
 123
 124         if((vuser != NULL) && !check_user_ok(conn, vuser, snum))
 125                 return False;
 126
 127         if (conn->force_user ||
 128                 conn->admin_user ||
 129             (lp_security() == SEC_SHARE)) {
 130                 uid = conn->uid;
 131                 gid = conn->gid;
 132                 current_user.groups = conn->groups;
 133                 current_user.ngroups = conn->ngroups;
 134                 token = conn->nt_user_token;
 135         } else {
 136                 if (!vuser) {
 137                         DEBUG(2,("change_to_user: Invalid vuid used %d\n",vuid));
 138                         return(False);
 139                 }
 140                 uid = vuser->uid;
 141                 gid = vuser->gid;
 142                 current_user.ngroups = vuser->n_groups;
 143                 current_user.groups  = vuser->groups;
 144                 token = vuser->nt_user_token;
 145         }
 146
 147         /*
 148          * See if we should force group for this service.
 149          * If so this overrides any group set in the force
 150          * user code.
 151          */
 152
 153         if((group_c = *lp_force_group(snum))) {
 154                 BOOL is_guest = False;
 155
 156                 if(group_c == '+') {
 157
 158                         /*
 159                          * Only force group if the user is a member of
 160                          * the service group. Check the group memberships for
 161                          * this user (we already have this) to
 162                          * see if we should force the group.
 163                          */
 164
 165                         int i;
 166                         for (i = 0; i < current_user.ngroups; i++) {
 167                                 if (current_user.groups[i] == conn->gid) {
 168                                         gid = conn->gid;
 169                                         break;
 170                                 }
 171                         }
 172                 } else {
 173                         gid = conn->gid;
 174                 }
 175
 176                 /*
 177                  * We've changed the group list in the token - we must
 178                  * re-create it.
 179                  */
 180
 181                 if (vuser && vuser->guest)
 182                         is_guest = True;
 183
 184                 token = create_nt_token(uid, gid, current_user.ngroups, current_user.groups, is_guest);
 185                 must_free_token = True;
 186         }
 187
 188         set_sec_ctx(uid, gid, current_user.ngroups, current_user.groups, token);
 189
 190         /*
 191          * Free the new token (as set_sec_ctx copies it).
 192          */
 193
 194         if (must_free_token)
 195                 delete_nt_token(&token);
 196
 197         current_user.conn = conn;
 198         current_user.vuid = vuid;
 199
 200         DEBUG(5,("change_to_user uid=(%d,%d) gid=(%d,%d)\n",
 201                  (int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
 202
 203         return(True);
 204 }
 205
 206 /****************************************************************************
 207  Go back to being root without changing the security context stack,
 208  but modify the current_user entries.
 209 ****************************************************************************/
 210
 211 BOOL change_to_root_user(void)
 212 {
 213         set_root_sec_ctx();
 214
 215         DEBUG(5,("change_to_root_user: now uid=(%d,%d) gid=(%d,%d)\n",
 216                 (int)getuid(),(int)geteuid(),(int)getgid(),(int)getegid()));
 217
 218         current_user.conn = NULL;
 219         current_user.vuid = UID_FIELD_INVALID;
 220
 221         return(True);
 222 }
 223
 224 /****************************************************************************
 225  Become the user of an authenticated connected named pipe.
 226  When this is called we are currently running as the connection
 227  user. Doesn't modify current_user.
 228 ****************************************************************************/
 229
 230 BOOL become_authenticated_pipe_user(pipes_struct *p)
 231 {
 232         if (!push_sec_ctx())
 233                 return False;
 234
 235         set_sec_ctx(p->pipe_user.uid, p->pipe_user.gid,
 236                     p->pipe_user.ngroups, p->pipe_user.groups, p->pipe_user.nt_user_token);
 237
 238         return True;
 239 }
 240
 241 /****************************************************************************
 242  Unbecome the user of an authenticated connected named pipe.
 243  When this is called we are running as the authenticated pipe
 244  user and need to go back to being the connection user. Doesn't modify
 245  current_user.
 246 ****************************************************************************/
 247
 248 BOOL unbecome_authenticated_pipe_user(void)
 249 {
 250         return pop_sec_ctx();
 251 }
 252
 253 /****************************************************************************
 254  Utility functions used by become_xxx/unbecome_xxx.
 255 ****************************************************************************/
 256
 257 struct conn_ctx {
 258         connection_struct *conn;
 259         uint16 vuid;
 260 };
 261
 262 /* A stack of current_user connection contexts. */
 263
 264 static struct conn_ctx conn_ctx_stack[MAX_SEC_CTX_DEPTH];
 265 static int conn_ctx_stack_ndx;
 266
 267 static void push_conn_ctx(void)
 268 {
 269         struct conn_ctx *ctx_p;
 270
 271         /* Check we don't overflow our stack */
 272
 273         if (conn_ctx_stack_ndx == MAX_SEC_CTX_DEPTH) {
 274                 DEBUG(0, ("Connection context stack overflow!\n"));
 275                 smb_panic("Connection context stack overflow!\n");
 276         }
 277
 278         /* Store previous user context */
 279         ctx_p = &conn_ctx_stack[conn_ctx_stack_ndx];
 280
 281         ctx_p->conn = current_user.conn;
 282         ctx_p->vuid = current_user.vuid;
 283
 284         DEBUG(3, ("push_conn_ctx(%u) : conn_ctx_stack_ndx = %d\n",
 285                 (unsigned int)ctx_p->vuid, conn_ctx_stack_ndx ));
 286
 287         conn_ctx_stack_ndx++;
 288 }
 289
 290 static void pop_conn_ctx(void)
 291 {
 292         struct conn_ctx *ctx_p;
 293
 294         /* Check for stack underflow. */
 295
 296         if (conn_ctx_stack_ndx == 0) {
 297                 DEBUG(0, ("Connection context stack underflow!\n"));
 298                 smb_panic("Connection context stack underflow!\n");
 299         }
 300
 301         conn_ctx_stack_ndx--;
 302         ctx_p = &conn_ctx_stack[conn_ctx_stack_ndx];
 303
 304         current_user.conn = ctx_p->conn;
 305         current_user.vuid = ctx_p->vuid;
 306
 307         ctx_p->conn = NULL;
 308         ctx_p->vuid = UID_FIELD_INVALID;
 309 }
 310
 311 void init_conn_ctx(void)
 312 {
 313     int i;
 314
 315     /* Initialise connection context stack */
 316         for (i = 0; i < MAX_SEC_CTX_DEPTH; i++) {
 317                 conn_ctx_stack[i].conn = NULL;
 318                 conn_ctx_stack[i].vuid = UID_FIELD_INVALID;
 319     }
 320 }
 321
 322 /****************************************************************************
 323  Temporarily become a root user.  Must match with unbecome_root(). Saves and
 324  restores the connection context.
 325 ****************************************************************************/
 326
 327 void become_root(void)
 328 {
 329         push_sec_ctx();
 330         push_conn_ctx();
 331         set_root_sec_ctx();
 332 }
 333
 334 /* Unbecome the root user */
 335
 336 void unbecome_root(void)
 337 {
 338         pop_sec_ctx();
 339         pop_conn_ctx();
 340 }
 341
 342 /****************************************************************************
 343  Push the current security context then force a change via change_to_user().
 344  Saves and restores the connection context.
 345 ****************************************************************************/
 346
 347 BOOL become_user(connection_struct *conn, uint16 vuid)
 348 {
 349         if (!push_sec_ctx())
 350                 return False;
 351
 352         push_conn_ctx();
 353
 354         if (!change_to_user(conn, vuid)) {
 355                 pop_sec_ctx();
 356                 pop_conn_ctx();
 357                 return False;
 358         }
 359
 360         return True;
 361 }
 362
 363 BOOL unbecome_user()
 364 {
 365         pop_sec_ctx();
 366         pop_conn_ctx();
 367         return True;
 368 }
 369
 370 /*****************************************************************
 371  *THE CANONICAL* convert name to SID function.
 372  Tries winbind first - then uses local lookup.
 373 *****************************************************************/
 374
 375 BOOL lookup_name(const char *name, DOM_SID *psid, enum SID_NAME_USE *name_type)
 376 {
 377         extern pstring global_myname;
 378         extern fstring global_myworkgroup;
 379         fstring sid;
 380         char *sep = lp_winbind_separator();
 381
 382         *name_type = SID_NAME_UNKNOWN;
 383
 384         if (!winbind_lookup_name(name, psid, name_type) || (*name_type != SID_NAME_USER) ) {
 385                 BOOL ret = False;
 386
 387                 DEBUG(10, ("lookup_name: winbind lookup for %s failed - trying local\n", name));
 388
 389                 /* If we are looking up a domain user, make sure it is
 390                    for the local machine only */
 391
 392                 if (strchr_m(name, sep[0]) || strchr_m(name, '\\')) {
 393                         fstring domain, username;
 394
 395                         split_domain_name(name, domain, username);
 396
 397                         switch (lp_server_role()) {
 398                                 case ROLE_DOMAIN_PDC:
 399                                 case ROLE_DOMAIN_BDC:
 400                                         if (strequal(domain, global_myworkgroup)) {
 401                                                 fstrcpy(domain, global_myname);
 402                                                 ret = local_lookup_name(domain, username, psid, name_type);
 403                                         }
 404                                         /* No break is deliberate here. JRA. */
 405                                 default:
 406                                         if (strcasecmp(global_myname, domain) != 0) {
 407                                                 DEBUG(5, ("lookup_name: domain %s is not local\n", domain));
 408                                                 ret = local_lookup_name(global_myname, username, psid, name_type);
 409                                         }
 410                         }
 411                 } else {
 412                         ret = local_lookup_name(global_myname, name, psid, name_type);
 413                 }
 414
 415                 if (ret) {
 416                         DEBUG(10,
 417                               ("lookup_name: (local) %s -> SID %s (type %u)\n",
 418                                name, sid_to_string(sid,psid),
 419                                (unsigned int)*name_type ));
 420                 } else {
 421                         DEBUG(10,("lookup name: (local) %s failed.\n", name));
 422                 }
 423
 424                 return ret;
 425         }
 426
 427         DEBUG(10,("lookup_name (winbindd): %s -> SID %s (type %u)\n",
 428                   name, sid_to_string(sid, psid),
 429                   (unsigned int)*name_type));
 430         return True;
 431 }
 432
 433 /*****************************************************************
 434  *THE CANONICAL* convert SID to name function.
 435  Tries winbind first - then uses local lookup.
 436 *****************************************************************/
 437
 438 BOOL lookup_sid(DOM_SID *sid, fstring dom_name, fstring name, enum SID_NAME_USE *name_type)
 439 {
 440         if (!name_type)
 441                 return False;
 442
 443         *name_type = SID_NAME_UNKNOWN;
 444
 445         /* Check if this is our own sid.  This should perhaps be done by
 446            winbind?  For the moment handle it here. */
 447
 448         if (sid->num_auths == 5) {
 449                 DOM_SID tmp_sid;
 450                 uint32 rid;
 451
 452                 sid_copy(&tmp_sid, sid);
 453                 sid_split_rid(&tmp_sid, &rid);
 454
 455                 if (sid_equal(&global_sam_sid, &tmp_sid)) {
 456
 457                         return map_domain_sid_to_name(&tmp_sid, dom_name) &&
 458                                 local_lookup_rid(rid, name, name_type);
 459                 }
 460         }
 461
 462         if (!winbind_lookup_sid(sid, dom_name, name, name_type)) {
 463                 fstring sid_str;
 464                 DOM_SID tmp_sid;
 465                 uint32 rid;
 466
 467                 DEBUG(10,("lookup_sid: winbind lookup for SID %s failed - trying local.\n", sid_to_string(sid_str, sid) ));
 468
 469                 sid_copy(&tmp_sid, sid);
 470                 sid_split_rid(&tmp_sid, &rid);
 471                 return map_domain_sid_to_name(&tmp_sid, dom_name) &&
 472                                 lookup_known_rid(&tmp_sid, rid, name, name_type);
 473         }
 474         return True;
 475 }
 476
 477 /*****************************************************************
 478  *THE CANONICAL* convert uid_t to SID function.
 479  Tries winbind first - then uses local lookup.
 480  Returns SID pointer.
 481 *****************************************************************/
 482
 483 DOM_SID *uid_to_sid(DOM_SID *psid, uid_t uid)
 484 {
 485         fstring sid;
 486
 487         if (!winbind_uid_to_sid(psid, uid)) {
 488                 DEBUG(10,("uid_to_sid: winbind lookup for uid %u failed - trying local.\n", (unsigned int)uid ));
 489
 490                 return local_uid_to_sid(psid, uid);
 491         }
 492
 493         DEBUG(10,("uid_to_sid: winbindd %u -> %s\n",
 494                 (unsigned int)uid, sid_to_string(sid, psid) ));
 495
 496         return psid;
 497 }
 498
 499 /*****************************************************************
 500  *THE CANONICAL* convert gid_t to SID function.
 501  Tries winbind first - then uses local lookup.
 502  Returns SID pointer.
 503 *****************************************************************/
 504
 505 DOM_SID *gid_to_sid(DOM_SID *psid, gid_t gid)
 506 {
 507         fstring sid;
 508
 509         if (!winbind_gid_to_sid(psid, gid)) {
 510                 DEBUG(10,("gid_to_sid: winbind lookup for gid %u failed - trying local.\n", (unsigned int)gid ));
 511
 512                 return local_gid_to_sid(psid, gid);
 513         }
 514
 515         DEBUG(10,("gid_to_sid: winbindd %u -> %s\n",
 516                 (unsigned int)gid, sid_to_string(sid,psid) ));
 517
 518         return psid;
 519 }
 520
 521 /*****************************************************************
 522  *THE CANONICAL* convert SID to uid function.
 523  Tries winbind first - then uses local lookup.
 524  Returns True if this name is a user sid and the conversion
 525  was done correctly, False if not. sidtype is set by this function.
 526 *****************************************************************/
 527
 528 BOOL sid_to_uid(DOM_SID *psid, uid_t *puid, enum SID_NAME_USE *sidtype)
 529 {
 530         fstring dom_name, name, sid_str;
 531         enum SID_NAME_USE name_type;
 532
 533         *sidtype = SID_NAME_UNKNOWN;
 534
 535         /*
 536          * First we must look up the name and decide if this is a user sid.
 537          */
 538
 539         if ( (!winbind_lookup_sid(psid, dom_name, name, &name_type)) || (name_type != SID_NAME_USER) ) {
 540                 DEBUG(10,("sid_to_uid: winbind lookup for sid %s failed - trying local.\n",
 541                                 sid_to_string(sid_str, psid) ));
 542
 543                 return local_sid_to_uid(puid, psid, sidtype);
 544         }
 545
 546         /*
 547          * Ensure this is a user sid.
 548          */
 549
 550         if (name_type != SID_NAME_USER) {
 551                 DEBUG(10,("sid_to_uid: winbind lookup succeeded but SID is not a uid (%u)\n",
 552                                 (unsigned int)name_type ));
 553                 return False;
 554         }
 555
 556         *sidtype = SID_NAME_USER;
 557
 558         /*
 559          * Get the uid for this SID.
 560          */
 561
 562         if (!winbind_sid_to_uid(puid, psid)) {
 563                 DEBUG(10,("sid_to_uid: winbind lookup for sid %s failed.\n",
 564                                 sid_to_string(sid_str, psid) ));
 565                 return False;
 566         }
 567
 568         DEBUG(10,("sid_to_uid: winbindd %s -> %u\n",
 569                 sid_to_string(sid_str, psid),
 570                 (unsigned int)*puid ));
 571
 572         return True;
 573 }
 574
 575 /*****************************************************************
 576  *THE CANONICAL* convert SID to gid function.
 577  Tries winbind first - then uses local lookup.
 578  Returns True if this name is a user sid and the conversion
 579  was done correctly, False if not.
 580 *****************************************************************/
 581
 582 BOOL sid_to_gid(DOM_SID *psid, gid_t *pgid, enum SID_NAME_USE *sidtype)
 583 {
 584         fstring dom_name, name, sid_str;
 585         enum SID_NAME_USE name_type;
 586
 587         *sidtype = SID_NAME_UNKNOWN;
 588
 589         /*
 590          * First we must look up the name and decide if this is a group sid.
 591          */
 592
 593         if (!winbind_lookup_sid(psid, dom_name, name, &name_type)) {
 594                 DEBUG(10,("sid_to_gid: winbind lookup for sid %s failed - trying local.\n",
 595                                 sid_to_string(sid_str, psid) ));
 596
 597                 return local_sid_to_gid(pgid, psid, sidtype);
 598         }
 599
 600         /*
 601          * Ensure this is a group sid.
 602          */
 603
 604         if ((name_type != SID_NAME_DOM_GRP) && (name_type != SID_NAME_ALIAS) && (name_type != SID_NAME_WKN_GRP)) {
 605                 DEBUG(10,("sid_to_gid: winbind lookup succeeded but SID is not a known group (%u)\n",
 606                                 (unsigned int)name_type ));
 607
 608                 return local_sid_to_gid(pgid, psid, sidtype);
 609         }
 610
 611         *sidtype = name_type;
 612
 613         /*
 614          * Get the gid for this SID.
 615          */
 616
 617         if (!winbind_sid_to_gid(pgid, psid)) {
 618                 DEBUG(10,("sid_to_gid: winbind lookup for sid %s failed.\n",
 619                                 sid_to_string(sid_str, psid) ));
 620                 return False;
 621         }
 622
 623         DEBUG(10,("gid_to_uid: winbindd %s -> %u\n",
 624                 sid_to_string(sid_str, psid),
 625                 (unsigned int)*pgid ));
 626
 627         return True;
 628 }