source3/lib/util_sid.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell                1992-1998
   5    Copyright (C) Luke Kenneth Caseson Leighton  1998-1999
   6    Copyright (C) Jeremy Allison                 1999
   7    Copyright (C) Stefan (metze) Metzmacher      2002
   8    Copyright (C) Simo Sorce                     2002
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26
  27 /*
  28  * Some useful sids
  29  */
  30
  31
  32 const DOM_SID global_sid_World_Domain =               /* Everyone domain */
  33 { 1, 0, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  34 const DOM_SID global_sid_World =                      /* Everyone */
  35 { 1, 1, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  36 const DOM_SID global_sid_Creator_Owner_Domain =       /* Creator Owner domain */
  37 { 1, 0, {0,0,0,0,0,3}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  38 const DOM_SID global_sid_NT_Authority =                 /* NT Authority */
  39 { 1, 0, {0,0,0,0,0,5}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  40 const DOM_SID global_sid_System =                       /* System */
  41 { 1, 1, {0,0,0,0,0,5}, {18,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  42 const DOM_SID global_sid_NULL =                         /* NULL sid */
  43 { 1, 1, {0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  44 const DOM_SID global_sid_Authenticated_Users =  /* All authenticated rids */
  45 { 1, 1, {0,0,0,0,0,5}, {11,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  46 const DOM_SID global_sid_Network =                      /* Network rids */
  47 { 1, 1, {0,0,0,0,0,5}, {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  48
  49 const DOM_SID global_sid_Creator_Owner =                /* Creator Owner */
  50 { 1, 1, {0,0,0,0,0,3}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  51 const DOM_SID global_sid_Creator_Group =                /* Creator Group */
  52 { 1, 1, {0,0,0,0,0,3}, {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  53 const DOM_SID global_sid_Anonymous =                    /* Anonymous login */
  54 { 1, 1, {0,0,0,0,0,5}, {7,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  55
  56 const DOM_SID global_sid_Builtin =                      /* Local well-known domain */
  57 { 1, 1, {0,0,0,0,0,5}, {32,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  58 const DOM_SID global_sid_Builtin_Administrators =       /* Builtin administrators */
  59 { 1, 2, {0,0,0,0,0,5}, {32,544,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  60 const DOM_SID global_sid_Builtin_Users =                /* Builtin users */
  61 { 1, 2, {0,0,0,0,0,5}, {32,545,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  62 const DOM_SID global_sid_Builtin_Guests =               /* Builtin guest users */
  63 { 1, 2, {0,0,0,0,0,5}, {32,546,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  64 const DOM_SID global_sid_Builtin_Power_Users =  /* Builtin power users */
  65 { 1, 2, {0,0,0,0,0,5}, {32,547,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  66 const DOM_SID global_sid_Builtin_Account_Operators =    /* Builtin account operators */
  67 { 1, 2, {0,0,0,0,0,5}, {32,548,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  68 const DOM_SID global_sid_Builtin_Server_Operators =     /* Builtin server operators */
  69 { 1, 2, {0,0,0,0,0,5}, {32,549,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  70 const DOM_SID global_sid_Builtin_Print_Operators =      /* Builtin print operators */
  71 { 1, 2, {0,0,0,0,0,5}, {32,550,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  72 const DOM_SID global_sid_Builtin_Backup_Operators =     /* Builtin backup operators */
  73 { 1, 2, {0,0,0,0,0,5}, {32,551,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  74 const DOM_SID global_sid_Builtin_Replicator =           /* Builtin replicator */
  75 { 1, 2, {0,0,0,0,0,5}, {32,552,0,0,0,0,0,0,0,0,0,0,0,0,0}};
  76
  77 #define SECURITY_NULL_SID_AUTHORITY    0
  78 #define SECURITY_WORLD_SID_AUTHORITY   1
  79 #define SECURITY_LOCAL_SID_AUTHORITY   2
  80 #define SECURITY_CREATOR_SID_AUTHORITY 3
  81 #define SECURITY_NT_AUTHORITY          5
  82
  83 /*
  84  * An NT compatible anonymous token.
  85  */
  86
  87 static DOM_SID anon_sid_array[3] =
  88 { { 1, 1, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
  89   { 1, 1, {0,0,0,0,0,5}, {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
  90   { 1, 1, {0,0,0,0,0,5}, {7,0,0,0,0,0,0,0,0,0,0,0,0,0,0}} };
  91 NT_USER_TOKEN anonymous_token = { 3, anon_sid_array, SE_NONE };
  92
  93 static DOM_SID system_sid_array[1] =
  94 { { 1, 1, {0,0,0,0,0,5}, {18,0,0,0,0,0,0,0,0,0,0,0,0,0,0}} };
  95 NT_USER_TOKEN system_token = { 1, system_sid_array, SE_ALL_PRIVS };
  96
  97 /****************************************************************************
  98  Lookup string names for SID types.
  99 ****************************************************************************/
 100
 101 static const struct {
 102         enum SID_NAME_USE sid_type;
 103         const char *string;
 104 } sid_name_type[] = {
 105         {SID_NAME_USER, "User"},
 106         {SID_NAME_DOM_GRP, "Domain Group"},
 107         {SID_NAME_DOMAIN, "Domain"},
 108         {SID_NAME_ALIAS, "Local Group"},
 109         {SID_NAME_WKN_GRP, "Well-known Group"},
 110         {SID_NAME_DELETED, "Deleted Account"},
 111         {SID_NAME_INVALID, "Invalid Account"},
 112         {SID_NAME_UNKNOWN, "UNKNOWN"},
 113         {SID_NAME_COMPUTER, "Computer"},
 114
 115         {(enum SID_NAME_USE)0, NULL}
 116 };
 117
 118 const char *sid_type_lookup(uint32 sid_type)
 119 {
 120         int i = 0;
 121
 122         /* Look through list */
 123         while(sid_name_type[i].sid_type != 0) {
 124                 if (sid_name_type[i].sid_type == sid_type)
 125                         return sid_name_type[i].string;
 126                 i++;
 127         }
 128
 129         /* Default return */
 130         return "SID *TYPE* is INVALID";
 131 }
 132
 133 /**************************************************************************
 134  Create the SYSTEM token.
 135 ***************************************************************************/
 136
 137 NT_USER_TOKEN *get_system_token(void)
 138 {
 139         return &system_token;
 140 }
 141
 142 /******************************************************************
 143  get the default domain/netbios name to be used when dealing
 144  with our passdb list of accounts
 145 ******************************************************************/
 146
 147 const char *get_global_sam_name(void)
 148 {
 149         if ((lp_server_role() == ROLE_DOMAIN_PDC) || (lp_server_role() == ROLE_DOMAIN_BDC)) {
 150                 return lp_workgroup();
 151         }
 152         return global_myname();
 153 }
 154
 155 /**************************************************************************
 156  Splits a name of format \DOMAIN\name or name into its two components.
 157  Sets the DOMAIN name to global_myname() if it has not been specified.
 158 ***************************************************************************/
 159
 160 void split_domain_name(const char *fullname, char *domain, char *name)
 161 {
 162         pstring full_name;
 163         const char *sep;
 164         char *p;
 165
 166         sep = lp_winbind_separator();
 167
 168         *domain = *name = '\0';
 169
 170         if (fullname[0] == sep[0] || fullname[0] == '\\')
 171                 fullname++;
 172
 173         pstrcpy(full_name, fullname);
 174         p = strchr_m(full_name+1, '\\');
 175         if (!p) p = strchr_m(full_name+1, sep[0]);
 176
 177         if (p != NULL) {
 178                 *p = 0;
 179                 fstrcpy(domain, full_name);
 180                 fstrcpy(name, p+1);
 181         } else {
 182                 fstrcpy(domain, get_global_sam_name());
 183                 fstrcpy(name, full_name);
 184         }
 185
 186         DEBUG(10,("split_domain_name:name '%s' split into domain :'%s' and user :'%s'\n",
 187                         fullname, domain, name));
 188 }
 189
 190 /****************************************************************************
 191  Test if a SID is wellknown and resolvable.
 192 ****************************************************************************/
 193
 194 BOOL resolvable_wellknown_sid(DOM_SID *sid)
 195 {
 196         uint32 ia = (sid->id_auth[5]) +
 197                         (sid->id_auth[4] << 8 ) +
 198                         (sid->id_auth[3] << 16) +
 199                         (sid->id_auth[2] << 24);
 200
 201         if (sid->sid_rev_num != SEC_DESC_REVISION || sid->num_auths < 1)
 202                 return False;
 203
 204         return (ia == SECURITY_WORLD_SID_AUTHORITY ||
 205                 ia == SECURITY_CREATOR_SID_AUTHORITY);
 206 }
 207
 208 /*****************************************************************
 209  Convert a SID to an ascii string.
 210 *****************************************************************/
 211
 212 char *sid_to_string(fstring sidstr_out, const DOM_SID *sid)
 213 {
 214         char subauth[16];
 215         int i;
 216         uint32 ia;
 217
 218         if (!sid) {
 219                 fstrcpy(sidstr_out, "(NULL SID)");
 220                 return sidstr_out;
 221         }
 222
 223         /*
 224          * BIG NOTE: this function only does SIDS where the identauth is not >= 2^32
 225          * in a range of 2^48.
 226          */
 227         ia = (sid->id_auth[5]) +
 228                 (sid->id_auth[4] << 8 ) +
 229                 (sid->id_auth[3] << 16) +
 230                 (sid->id_auth[2] << 24);
 231
 232         slprintf(sidstr_out, sizeof(fstring) - 1, "S-%u-%lu", (unsigned int)sid->sid_rev_num, (unsigned long)ia);
 233
 234         for (i = 0; i < sid->num_auths; i++) {
 235                 slprintf(subauth, sizeof(subauth)-1, "-%lu", (unsigned long)sid->sub_auths[i]);
 236                 fstrcat(sidstr_out, subauth);
 237         }
 238
 239         return sidstr_out;
 240 }
 241
 242 /*****************************************************************
 243  Useful function for debug lines.
 244 *****************************************************************/
 245
 246 const char *sid_string_static(const DOM_SID *sid)
 247 {
 248         static fstring sid_str;
 249         sid_to_string(sid_str, sid);
 250         return sid_str;
 251 }
 252
 253 /*****************************************************************
 254  Convert a string to a SID. Returns True on success, False on fail.
 255 *****************************************************************/
 256
 257 BOOL string_to_sid(DOM_SID *sidout, const char *sidstr)
 258 {
 259         pstring tok;
 260         char *q;
 261         const char *p;
 262         /* BIG NOTE: this function only does SIDS where the identauth is not >= 2^32 */
 263         uint32 ia;
 264
 265         if (StrnCaseCmp( sidstr, "S-", 2)) {
 266                 DEBUG(0,("string_to_sid: Sid %s does not start with 'S-'.\n", sidstr));
 267                 return False;
 268         }
 269
 270         memset((char *)sidout, '\0', sizeof(DOM_SID));
 271
 272         p = q = SMB_STRDUP(sidstr + 2);
 273         if (p == NULL) {
 274                 DEBUG(0, ("string_to_sid: out of memory!\n"));
 275                 return False;
 276         }
 277
 278         if (!next_token(&p, tok, "-", sizeof(tok))) {
 279                 DEBUG(0,("string_to_sid: Sid %s is not in a valid format.\n", sidstr));
 280                 SAFE_FREE(q);
 281                 return False;
 282         }
 283
 284         /* Get the revision number. */
 285         sidout->sid_rev_num = (uint8)strtoul(tok, NULL, 10);
 286
 287         if (!next_token(&p, tok, "-", sizeof(tok))) {
 288                 DEBUG(0,("string_to_sid: Sid %s is not in a valid format.\n", sidstr));
 289                 SAFE_FREE(q);
 290                 return False;
 291         }
 292
 293         /* identauth in decimal should be <  2^32 */
 294         ia = (uint32)strtoul(tok, NULL, 10);
 295
 296         /* NOTE - the ia value is in big-endian format. */
 297         sidout->id_auth[0] = 0;
 298         sidout->id_auth[1] = 0;
 299         sidout->id_auth[2] = (ia & 0xff000000) >> 24;
 300         sidout->id_auth[3] = (ia & 0x00ff0000) >> 16;
 301         sidout->id_auth[4] = (ia & 0x0000ff00) >> 8;
 302         sidout->id_auth[5] = (ia & 0x000000ff);
 303
 304         sidout->num_auths = 0;
 305
 306         while(next_token(&p, tok, "-", sizeof(tok)) &&
 307                 sidout->num_auths < MAXSUBAUTHS) {
 308                 /*
 309                  * NOTE - the subauths are in native machine-endian format. They
 310                  * are converted to little-endian when linearized onto the wire.
 311                  */
 312                 sid_append_rid(sidout, (uint32)strtoul(tok, NULL, 10));
 313         }
 314
 315         SAFE_FREE(q);
 316         return True;
 317 }
 318
 319 DOM_SID *string_sid_talloc(TALLOC_CTX *mem_ctx, const char *sidstr)
 320 {
 321         DOM_SID *result = TALLOC_P(mem_ctx, DOM_SID);
 322
 323         if (result == NULL)
 324                 return NULL;
 325
 326         if (!string_to_sid(result, sidstr))
 327                 return NULL;
 328
 329         return result;
 330 }
 331
 332 /*****************************************************************
 333  Add a rid to the end of a sid
 334 *****************************************************************/
 335
 336 BOOL sid_append_rid(DOM_SID *sid, uint32 rid)
 337 {
 338         if (sid->num_auths < MAXSUBAUTHS) {
 339                 sid->sub_auths[sid->num_auths++] = rid;
 340                 return True;
 341         }
 342         return False;
 343 }
 344
 345 /*****************************************************************
 346  Removes the last rid from the end of a sid
 347 *****************************************************************/
 348
 349 BOOL sid_split_rid(DOM_SID *sid, uint32 *rid)
 350 {
 351         if (sid->num_auths > 0) {
 352                 sid->num_auths--;
 353                 *rid = sid->sub_auths[sid->num_auths];
 354                 return True;
 355         }
 356         return False;
 357 }
 358
 359 /*****************************************************************
 360  Return the last rid from the end of a sid
 361 *****************************************************************/
 362
 363 BOOL sid_peek_rid(const DOM_SID *sid, uint32 *rid)
 364 {
 365         if (!sid || !rid)
 366                 return False;
 367
 368         if (sid->num_auths > 0) {
 369                 *rid = sid->sub_auths[sid->num_auths - 1];
 370                 return True;
 371         }
 372         return False;
 373 }
 374
 375 /*****************************************************************
 376  Return the last rid from the end of a sid
 377  and check the sid against the exp_dom_sid
 378 *****************************************************************/
 379
 380 BOOL sid_peek_check_rid(const DOM_SID *exp_dom_sid, const DOM_SID *sid, uint32 *rid)
 381 {
 382         if (!exp_dom_sid || !sid || !rid)
 383                 return False;
 384
 385         if (sid->num_auths != (exp_dom_sid->num_auths+1)) {
 386                 return False;
 387         }
 388
 389         if (sid_compare_domain(exp_dom_sid, sid)!=0){
 390                 *rid=(-1);
 391                 return False;
 392         }
 393
 394         return sid_peek_rid(sid, rid);
 395 }
 396
 397 /*****************************************************************
 398  Copies a sid
 399 *****************************************************************/
 400
 401 void sid_copy(DOM_SID *dst, const DOM_SID *src)
 402 {
 403         int i;
 404
 405         ZERO_STRUCTP(dst);
 406
 407         dst->sid_rev_num = src->sid_rev_num;
 408         dst->num_auths = src->num_auths;
 409
 410         memcpy(&dst->id_auth[0], &src->id_auth[0], sizeof(src->id_auth));
 411
 412         for (i = 0; i < src->num_auths; i++)
 413                 dst->sub_auths[i] = src->sub_auths[i];
 414 }
 415
 416 /*****************************************************************
 417  Write a sid out into on-the-wire format.
 418 *****************************************************************/
 419
 420 BOOL sid_linearize(char *outbuf, size_t len, const DOM_SID *sid)
 421 {
 422         size_t i;
 423
 424         if (len < sid_size(sid))
 425                 return False;
 426
 427         SCVAL(outbuf,0,sid->sid_rev_num);
 428         SCVAL(outbuf,1,sid->num_auths);
 429         memcpy(&outbuf[2], sid->id_auth, 6);
 430         for(i = 0; i < sid->num_auths; i++)
 431                 SIVAL(outbuf, 8 + (i*4), sid->sub_auths[i]);
 432
 433         return True;
 434 }
 435
 436 /*****************************************************************
 437  Parse a on-the-wire SID to a DOM_SID.
 438 *****************************************************************/
 439
 440 BOOL sid_parse(const char *inbuf, size_t len, DOM_SID *sid)
 441 {
 442         int i;
 443         if (len < 8)
 444                 return False;
 445
 446         ZERO_STRUCTP(sid);
 447
 448         sid->sid_rev_num = CVAL(inbuf, 0);
 449         sid->num_auths = CVAL(inbuf, 1);
 450         memcpy(sid->id_auth, inbuf+2, 6);
 451         if (len < 8 + sid->num_auths*4)
 452                 return False;
 453         for (i=0;i<sid->num_auths;i++)
 454                 sid->sub_auths[i] = IVAL(inbuf, 8+i*4);
 455         return True;
 456 }
 457
 458 /*****************************************************************
 459  Compare the auth portion of two sids.
 460 *****************************************************************/
 461
 462 static int sid_compare_auth(const DOM_SID *sid1, const DOM_SID *sid2)
 463 {
 464         int i;
 465
 466         if (sid1 == sid2)
 467                 return 0;
 468         if (!sid1)
 469                 return -1;
 470         if (!sid2)
 471                 return 1;
 472
 473         if (sid1->sid_rev_num != sid2->sid_rev_num)
 474                 return sid1->sid_rev_num - sid2->sid_rev_num;
 475
 476         for (i = 0; i < 6; i++)
 477                 if (sid1->id_auth[i] != sid2->id_auth[i])
 478                         return sid1->id_auth[i] - sid2->id_auth[i];
 479
 480         return 0;
 481 }
 482
 483 /*****************************************************************
 484  Compare two sids.
 485 *****************************************************************/
 486
 487 int sid_compare(const DOM_SID *sid1, const DOM_SID *sid2)
 488 {
 489         int i;
 490
 491         if (sid1 == sid2)
 492                 return 0;
 493         if (!sid1)
 494                 return -1;
 495         if (!sid2)
 496                 return 1;
 497
 498         /* Compare most likely different rids, first: i.e start at end */
 499         if (sid1->num_auths != sid2->num_auths)
 500                 return sid1->num_auths - sid2->num_auths;
 501
 502         for (i = sid1->num_auths-1; i >= 0; --i)
 503                 if (sid1->sub_auths[i] != sid2->sub_auths[i])
 504                         return sid1->sub_auths[i] - sid2->sub_auths[i];
 505
 506         return sid_compare_auth(sid1, sid2);
 507 }
 508
 509 /*****************************************************************
 510  See if 2 SIDs are in the same domain
 511  this just compares the leading sub-auths
 512 *****************************************************************/
 513
 514 int sid_compare_domain(const DOM_SID *sid1, const DOM_SID *sid2)
 515 {
 516         int n, i;
 517
 518         n = MIN(sid1->num_auths, sid2->num_auths);
 519
 520         for (i = n-1; i >= 0; --i)
 521                 if (sid1->sub_auths[i] != sid2->sub_auths[i])
 522                         return sid1->sub_auths[i] - sid2->sub_auths[i];
 523
 524         return sid_compare_auth(sid1, sid2);
 525 }
 526
 527 /*****************************************************************
 528  Compare two sids.
 529 *****************************************************************/
 530
 531 BOOL sid_equal(const DOM_SID *sid1, const DOM_SID *sid2)
 532 {
 533         return sid_compare(sid1, sid2) == 0;
 534 }
 535
 536 /*****************************************************************
 537  Check if the SID is the builtin SID (S-1-5-32).
 538 *****************************************************************/
 539
 540 BOOL sid_check_is_builtin(const DOM_SID *sid)
 541 {
 542         return sid_equal(sid, &global_sid_Builtin);
 543 }
 544
 545 /*****************************************************************
 546  Check if the SID is one of the builtin SIDs (S-1-5-32-a).
 547 *****************************************************************/
 548
 549 BOOL sid_check_is_in_builtin(const DOM_SID *sid)
 550 {
 551         DOM_SID dom_sid;
 552         uint32 rid;
 553
 554         sid_copy(&dom_sid, sid);
 555         sid_split_rid(&dom_sid, &rid);
 556
 557         return sid_equal(&dom_sid, &global_sid_Builtin);
 558 }
 559
 560 /*****************************************************************
 561  Calculates size of a sid.
 562 *****************************************************************/
 563
 564 size_t sid_size(const DOM_SID *sid)
 565 {
 566         if (sid == NULL)
 567                 return 0;
 568
 569         return sid->num_auths * sizeof(uint32) + 8;
 570 }
 571
 572 /*****************************************************************
 573  Returns true if SID is internal (and non-mappable).
 574 *****************************************************************/
 575
 576 BOOL non_mappable_sid(DOM_SID *sid)
 577 {
 578         DOM_SID dom;
 579         uint32 rid;
 580
 581         sid_copy(&dom, sid);
 582         sid_split_rid(&dom, &rid);
 583
 584         if (sid_equal(&dom, &global_sid_Builtin))
 585                 return True;
 586
 587         if (sid_equal(&dom, &global_sid_NT_Authority))
 588                 return True;
 589
 590         return False;
 591 }
 592
 593 /*****************************************************************
 594  Return the binary string representation of a DOM_SID.
 595  Caller must free.
 596 *****************************************************************/
 597
 598 char *sid_binstring(const DOM_SID *sid)
 599 {
 600         char *buf, *s;
 601         int len = sid_size(sid);
 602         buf = SMB_MALLOC(len);
 603         if (!buf)
 604                 return NULL;
 605         sid_linearize(buf, len, sid);
 606         s = binary_string(buf, len);
 607         free(buf);
 608         return s;
 609 }
 610
 611 /*******************************************************************
 612  Tallocs a duplicate SID.
 613 ********************************************************************/
 614
 615 DOM_SID *sid_dup_talloc(TALLOC_CTX *ctx, const DOM_SID *src)
 616 {
 617         DOM_SID *dst;
 618
 619         if(!src)
 620                 return NULL;
 621
 622         if((dst = TALLOC_ZERO_P(ctx, DOM_SID)) != NULL) {
 623                 sid_copy( dst, src);
 624         }
 625
 626         return dst;
 627 }
 628
 629 /********************************************************************
 630  Add SID to an array SIDs
 631 ********************************************************************/
 632
 633 void add_sid_to_array(TALLOC_CTX *mem_ctx, const DOM_SID *sid,
 634                       DOM_SID **sids, int *num)
 635 {
 636         if (mem_ctx != NULL)
 637                 *sids = TALLOC_REALLOC_ARRAY(mem_ctx, *sids, DOM_SID,
 638                                              (*num)+1);
 639         else
 640                 *sids = SMB_REALLOC_ARRAY(*sids, DOM_SID, (*num)+1);
 641
 642         if (*sids == NULL)
 643                 return;
 644
 645         sid_copy(&((*sids)[*num]), sid);
 646         *num += 1;
 647
 648         return;
 649 }
 650
 651
 652 /********************************************************************
 653  Add SID to an array SIDs ensuring that it is not already there
 654 ********************************************************************/
 655
 656 void add_sid_to_array_unique(TALLOC_CTX *mem_ctx, const DOM_SID *sid,
 657                              DOM_SID **sids, int *num_sids)
 658 {
 659         int i;
 660
 661         for (i=0; i<(*num_sids); i++) {
 662                 if (sid_compare(sid, &(*sids)[i]) == 0)
 663                         return;
 664         }
 665
 666         add_sid_to_array(mem_ctx, sid, sids, num_sids);
 667 }
 668
 669 /********************************************************************
 670  Remove SID from an array
 671 ********************************************************************/
 672
 673 void del_sid_from_array(const DOM_SID *sid, DOM_SID **sids, int *num)
 674 {
 675         DOM_SID *sid_list = *sids;
 676         int i;
 677
 678         for ( i=0; i<*num; i++ ) {
 679
 680                 /* if we find the SID, then decrement the count
 681                    and break out of the loop */
 682
 683                 if ( sid_equal(sid, &sid_list[i]) ) {
 684                         *num -= 1;
 685                         break;
 686                 }
 687         }
 688
 689         /* This loop will copy the remainder of the array
 690            if i < num of sids ni the array */
 691
 692         for ( ; i<*num; i++ )
 693                 sid_copy( &sid_list[i], &sid_list[i+1] );
 694
 695         return;
 696 }
 697