libcli/security/security_descriptor.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    security descriptror utility functions
   5
   6    Copyright (C) Andrew Tridgell                2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "libcli/security/security.h"
  24
  25 /*
  26   return a blank security descriptor (no owners, dacl or sacl)
  27 */
  28 struct security_descriptor *security_descriptor_initialise(TALLOC_CTX *mem_ctx)
  29 {
  30         struct security_descriptor *sd;
  31
  32         sd = talloc(mem_ctx, struct security_descriptor);
  33         if (!sd) {
  34                 return NULL;
  35         }
  36
  37         sd->revision = SD_REVISION;
  38         /* we mark as self relative, even though it isn't while it remains
  39            a pointer in memory because this simplifies the ndr code later.
  40            All SDs that we store/emit are in fact SELF_RELATIVE
  41         */
  42         sd->type = SEC_DESC_SELF_RELATIVE;
  43
  44         sd->owner_sid = NULL;
  45         sd->group_sid = NULL;
  46         sd->sacl = NULL;
  47         sd->dacl = NULL;
  48
  49         return sd;
  50 }
  51
  52 struct security_acl *security_acl_dup(TALLOC_CTX *mem_ctx,
  53                                              const struct security_acl *oacl)
  54 {
  55         struct security_acl *nacl;
  56
  57         if (oacl == NULL) {
  58                 return NULL;
  59         }
  60
  61         if (oacl->aces == NULL && oacl->num_aces > 0) {
  62                 return NULL;
  63         }
  64
  65         nacl = talloc (mem_ctx, struct security_acl);
  66         if (nacl == NULL) {
  67                 return NULL;
  68         }
  69
  70         *nacl = (struct security_acl) {
  71                 .revision = oacl->revision,
  72                 .size     = oacl->size,
  73                 .num_aces = oacl->num_aces,
  74         };
  75         if (nacl->num_aces == 0) {
  76                 return nacl;
  77         }
  78
  79         nacl->aces = (struct security_ace *)talloc_memdup (nacl, oacl->aces, sizeof(struct security_ace) * oacl->num_aces);
  80         if (nacl->aces == NULL) {
  81                 goto failed;
  82         }
  83
  84         return nacl;
  85
  86  failed:
  87         talloc_free (nacl);
  88         return NULL;
  89
  90 }
  91
  92 struct security_acl *security_acl_concatenate(TALLOC_CTX *mem_ctx,
  93                                               const struct security_acl *acl1,
  94                                               const struct security_acl *acl2)
  95 {
  96         struct security_acl *nacl;
  97         uint32_t i;
  98
  99         if (!acl1 && !acl2)
 100                 return NULL;
 101
 102         if (!acl1){
 103                 nacl = security_acl_dup(mem_ctx, acl2);
 104                 return nacl;
 105         }
 106
 107         if (!acl2){
 108                 nacl = security_acl_dup(mem_ctx, acl1);
 109                 return nacl;
 110         }
 111
 112         nacl = talloc (mem_ctx, struct security_acl);
 113         if (nacl == NULL) {
 114                 return NULL;
 115         }
 116
 117         nacl->revision = acl1->revision;
 118         nacl->size = acl1->size + acl2->size;
 119         nacl->num_aces = acl1->num_aces + acl2->num_aces;
 120
 121         if (nacl->num_aces == 0)
 122                 return nacl;
 123
 124         nacl->aces = (struct security_ace *)talloc_array (mem_ctx, struct security_ace, acl1->num_aces+acl2->num_aces);
 125         if ((nacl->aces == NULL) && (nacl->num_aces > 0)) {
 126                 goto failed;
 127         }
 128
 129         for (i = 0; i < acl1->num_aces; i++)
 130                 nacl->aces[i] = acl1->aces[i];
 131         for (i = 0; i < acl2->num_aces; i++)
 132                 nacl->aces[i + acl1->num_aces] = acl2->aces[i];
 133
 134         return nacl;
 135
 136  failed:
 137         talloc_free (nacl);
 138         return NULL;
 139
 140 }
 141
 142 /*
 143    talloc and copy a security descriptor
 144  */
 145 struct security_descriptor *security_descriptor_copy(TALLOC_CTX *mem_ctx,
 146                                                      const struct security_descriptor *osd)
 147 {
 148         struct security_descriptor *nsd;
 149
 150         nsd = talloc_zero(mem_ctx, struct security_descriptor);
 151         if (!nsd) {
 152                 return NULL;
 153         }
 154
 155         if (osd->owner_sid) {
 156                 nsd->owner_sid = dom_sid_dup(nsd, osd->owner_sid);
 157                 if (nsd->owner_sid == NULL) {
 158                         goto failed;
 159                 }
 160         }
 161
 162         if (osd->group_sid) {
 163                 nsd->group_sid = dom_sid_dup(nsd, osd->group_sid);
 164                 if (nsd->group_sid == NULL) {
 165                         goto failed;
 166                 }
 167         }
 168
 169         if (osd->sacl) {
 170                 nsd->sacl = security_acl_dup(nsd, osd->sacl);
 171                 if (nsd->sacl == NULL) {
 172                         goto failed;
 173                 }
 174         }
 175
 176         if (osd->dacl) {
 177                 nsd->dacl = security_acl_dup(nsd, osd->dacl);
 178                 if (nsd->dacl == NULL) {
 179                         goto failed;
 180                 }
 181         }
 182
 183         nsd->revision = osd->revision;
 184         nsd->type = osd->type;
 185
 186         return nsd;
 187
 188  failed:
 189         talloc_free(nsd);
 190
 191         return NULL;
 192 }
 193
 194 NTSTATUS security_descriptor_for_client(TALLOC_CTX *mem_ctx,
 195                                         const struct security_descriptor *ssd,
 196                                         uint32_t sec_info,
 197                                         uint32_t access_granted,
 198                                         struct security_descriptor **_csd)
 199 {
 200         struct security_descriptor *csd = NULL;
 201         uint32_t access_required = 0;
 202
 203         *_csd = NULL;
 204
 205         if (sec_info & (SECINFO_OWNER|SECINFO_GROUP)) {
 206                 access_required |= SEC_STD_READ_CONTROL;
 207         }
 208         if (sec_info & SECINFO_DACL) {
 209                 access_required |= SEC_STD_READ_CONTROL;
 210         }
 211         if (sec_info & SECINFO_SACL) {
 212                 access_required |= SEC_FLAG_SYSTEM_SECURITY;
 213         }
 214
 215         if (access_required & (~access_granted)) {
 216                 return NT_STATUS_ACCESS_DENIED;
 217         }
 218
 219         /*
 220          * make a copy...
 221          */
 222         csd = security_descriptor_copy(mem_ctx, ssd);
 223         if (csd == NULL) {
 224                 return NT_STATUS_NO_MEMORY;
 225         }
 226
 227         /*
 228          * ... and remove everthing not wanted
 229          */
 230
 231         if (!(sec_info & SECINFO_OWNER)) {
 232                 TALLOC_FREE(csd->owner_sid);
 233                 csd->type &= ~SEC_DESC_OWNER_DEFAULTED;
 234         }
 235         if (!(sec_info & SECINFO_GROUP)) {
 236                 TALLOC_FREE(csd->group_sid);
 237                 csd->type &= ~SEC_DESC_GROUP_DEFAULTED;
 238         }
 239         if (!(sec_info & SECINFO_DACL)) {
 240                 TALLOC_FREE(csd->dacl);
 241                 csd->type &= ~(
 242                         SEC_DESC_DACL_PRESENT |
 243                         SEC_DESC_DACL_DEFAULTED|
 244                         SEC_DESC_DACL_AUTO_INHERIT_REQ |
 245                         SEC_DESC_DACL_AUTO_INHERITED |
 246                         SEC_DESC_DACL_PROTECTED |
 247                         SEC_DESC_DACL_TRUSTED);
 248         }
 249         if (!(sec_info & SECINFO_SACL)) {
 250                 TALLOC_FREE(csd->sacl);
 251                 csd->type &= ~(
 252                         SEC_DESC_SACL_PRESENT |
 253                         SEC_DESC_SACL_DEFAULTED |
 254                         SEC_DESC_SACL_AUTO_INHERIT_REQ |
 255                         SEC_DESC_SACL_AUTO_INHERITED |
 256                         SEC_DESC_SACL_PROTECTED |
 257                         SEC_DESC_SERVER_SECURITY);
 258         }
 259
 260         *_csd = csd;
 261         return NT_STATUS_OK;
 262 }
 263
 264 /*
 265   add an ACE to an ACL of a security_descriptor
 266 */
 267
 268 static NTSTATUS security_descriptor_acl_add(struct security_descriptor *sd,
 269                                             bool add_to_sacl,
 270                                             const struct security_ace *ace)
 271 {
 272         struct security_acl *acl = NULL;
 273
 274         if (add_to_sacl) {
 275                 acl = sd->sacl;
 276         } else {
 277                 acl = sd->dacl;
 278         }
 279
 280         if (acl == NULL) {
 281                 acl = talloc(sd, struct security_acl);
 282                 if (acl == NULL) {
 283                         return NT_STATUS_NO_MEMORY;
 284                 }
 285                 acl->revision = SECURITY_ACL_REVISION_NT4;
 286                 acl->size     = 0;
 287                 acl->num_aces = 0;
 288                 acl->aces     = NULL;
 289         }
 290
 291         acl->aces = talloc_realloc(acl, acl->aces,
 292                                    struct security_ace, acl->num_aces+1);
 293         if (acl->aces == NULL) {
 294                 return NT_STATUS_NO_MEMORY;
 295         }
 296
 297         acl->aces[acl->num_aces] = *ace;
 298
 299         switch (acl->aces[acl->num_aces].type) {
 300         case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT:
 301         case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT:
 302         case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT:
 303         case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT:
 304                 acl->revision = SECURITY_ACL_REVISION_ADS;
 305                 break;
 306         default:
 307                 break;
 308         }
 309
 310         acl->num_aces++;
 311
 312         if (add_to_sacl) {
 313                 sd->sacl = acl;
 314                 sd->type |= SEC_DESC_SACL_PRESENT;
 315         } else {
 316                 sd->dacl = acl;
 317                 sd->type |= SEC_DESC_DACL_PRESENT;
 318         }
 319
 320         return NT_STATUS_OK;
 321 }
 322
 323 /*
 324   add an ACE to the SACL of a security_descriptor
 325 */
 326
 327 NTSTATUS security_descriptor_sacl_add(struct security_descriptor *sd,
 328                                       const struct security_ace *ace)
 329 {
 330         return security_descriptor_acl_add(sd, true, ace);
 331 }
 332
 333 /*
 334   add an ACE to the DACL of a security_descriptor
 335 */
 336
 337 NTSTATUS security_descriptor_dacl_add(struct security_descriptor *sd,
 338                                       const struct security_ace *ace)
 339 {
 340         return security_descriptor_acl_add(sd, false, ace);
 341 }
 342
 343 /*
 344   delete the ACE corresponding to the given trustee in an ACL of a
 345   security_descriptor
 346 */
 347
 348 static NTSTATUS security_descriptor_acl_del(struct security_descriptor *sd,
 349                                             bool sacl_del,
 350                                             const struct dom_sid *trustee)
 351 {
 352         uint32_t i;
 353         bool found = false;
 354         struct security_acl *acl = NULL;
 355
 356         if (sacl_del) {
 357                 acl = sd->sacl;
 358         } else {
 359                 acl = sd->dacl;
 360         }
 361
 362         if (acl == NULL) {
 363                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 364         }
 365
 366         /* there can be multiple ace's for one trustee */
 367         for (i=0;i<acl->num_aces;i++) {
 368                 if (dom_sid_equal(trustee, &acl->aces[i].trustee)) {
 369                         memmove(&acl->aces[i], &acl->aces[i+1],
 370                                 sizeof(acl->aces[i]) * (acl->num_aces - (i+1)));
 371                         acl->num_aces--;
 372                         if (acl->num_aces == 0) {
 373                                 acl->aces = NULL;
 374                         }
 375                         found = true;
 376                 }
 377         }
 378
 379         if (!found) {
 380                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 381         }
 382
 383         acl->revision = SECURITY_ACL_REVISION_NT4;
 384
 385         for (i=0;i<acl->num_aces;i++) {
 386                 switch (acl->aces[i].type) {
 387                 case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT:
 388                 case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT:
 389                 case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT:
 390                 case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT:
 391                         acl->revision = SECURITY_ACL_REVISION_ADS;
 392                         return NT_STATUS_OK;
 393                 default:
 394                         break; /* only for the switch statement */
 395                 }
 396         }
 397
 398         return NT_STATUS_OK;
 399 }
 400
 401 /*
 402   delete the ACE corresponding to the given trustee in the DACL of a
 403   security_descriptor
 404 */
 405
 406 NTSTATUS security_descriptor_dacl_del(struct security_descriptor *sd,
 407                                       const struct dom_sid *trustee)
 408 {
 409         return security_descriptor_acl_del(sd, false, trustee);
 410 }
 411
 412 /*
 413   delete the ACE corresponding to the given trustee in the SACL of a
 414   security_descriptor
 415 */
 416
 417 NTSTATUS security_descriptor_sacl_del(struct security_descriptor *sd,
 418                                       const struct dom_sid *trustee)
 419 {
 420         return security_descriptor_acl_del(sd, true, trustee);
 421 }
 422
 423 /*
 424   compare two security ace structures
 425 */
 426 bool security_ace_equal(const struct security_ace *ace1,
 427                         const struct security_ace *ace2)
 428 {
 429         if (ace1 == ace2) {
 430                 return true;
 431         }
 432         if ((ace1 == NULL) || (ace2 == NULL)) {
 433                 return false;
 434         }
 435         if (ace1->type != ace2->type) {
 436                 return false;
 437         }
 438         if (ace1->flags != ace2->flags) {
 439                 return false;
 440         }
 441         if (ace1->access_mask != ace2->access_mask) {
 442                 return false;
 443         }
 444         if (!dom_sid_equal(&ace1->trustee, &ace2->trustee)) {
 445                 return false;
 446         }
 447
 448         return true;
 449 }
 450
 451
 452 /*
 453   compare two security acl structures
 454 */
 455 bool security_acl_equal(const struct security_acl *acl1,
 456                         const struct security_acl *acl2)
 457 {
 458         uint32_t i;
 459
 460         if (acl1 == acl2) return true;
 461         if (!acl1 || !acl2) return false;
 462         if (acl1->revision != acl2->revision) return false;
 463         if (acl1->num_aces != acl2->num_aces) return false;
 464
 465         for (i=0;i<acl1->num_aces;i++) {
 466                 if (!security_ace_equal(&acl1->aces[i], &acl2->aces[i])) return false;
 467         }
 468         return true;
 469 }
 470
 471 /*
 472   compare two security descriptors.
 473 */
 474 bool security_descriptor_equal(const struct security_descriptor *sd1,
 475                                const struct security_descriptor *sd2)
 476 {
 477         if (sd1 == sd2) return true;
 478         if (!sd1 || !sd2) return false;
 479         if (sd1->revision != sd2->revision) return false;
 480         if (sd1->type != sd2->type) return false;
 481
 482         if (!dom_sid_equal(sd1->owner_sid, sd2->owner_sid)) return false;
 483         if (!dom_sid_equal(sd1->group_sid, sd2->group_sid)) return false;
 484         if (!security_acl_equal(sd1->sacl, sd2->sacl))      return false;
 485         if (!security_acl_equal(sd1->dacl, sd2->dacl))      return false;
 486
 487         return true;
 488 }
 489
 490 /*
 491   compare two security descriptors, but allow certain (missing) parts
 492   to be masked out of the comparison
 493 */
 494 bool security_descriptor_mask_equal(const struct security_descriptor *sd1,
 495                                     const struct security_descriptor *sd2,
 496                                     uint32_t mask)
 497 {
 498         if (sd1 == sd2) return true;
 499         if (!sd1 || !sd2) return false;
 500         if (sd1->revision != sd2->revision) return false;
 501         if ((sd1->type & mask) != (sd2->type & mask)) return false;
 502
 503         if (!dom_sid_equal(sd1->owner_sid, sd2->owner_sid)) return false;
 504         if (!dom_sid_equal(sd1->group_sid, sd2->group_sid)) return false;
 505         if ((mask & SEC_DESC_DACL_PRESENT) && !security_acl_equal(sd1->dacl, sd2->dacl))      return false;
 506         if ((mask & SEC_DESC_SACL_PRESENT) && !security_acl_equal(sd1->sacl, sd2->sacl))      return false;
 507
 508         return true;
 509 }
 510
 511
 512 static struct security_descriptor *security_descriptor_appendv(struct security_descriptor *sd,
 513                                                                bool add_ace_to_sacl,
 514                                                                va_list ap)
 515 {
 516         const char *sidstr;
 517
 518         while ((sidstr = va_arg(ap, const char *))) {
 519                 struct dom_sid *sid;
 520                 struct security_ace *ace = talloc_zero(sd, struct security_ace);
 521                 NTSTATUS status;
 522
 523                 if (ace == NULL) {
 524                         talloc_free(sd);
 525                         return NULL;
 526                 }
 527                 ace->type = va_arg(ap, unsigned int);
 528                 ace->access_mask = va_arg(ap, unsigned int);
 529                 ace->flags = va_arg(ap, unsigned int);
 530                 sid = dom_sid_parse_talloc(ace, sidstr);
 531                 if (sid == NULL) {
 532                         talloc_free(sd);
 533                         return NULL;
 534                 }
 535                 ace->trustee = *sid;
 536                 if (add_ace_to_sacl) {
 537                         status = security_descriptor_sacl_add(sd, ace);
 538                 } else {
 539                         status = security_descriptor_dacl_add(sd, ace);
 540                 }
 541                 /* TODO: check: would talloc_free(ace) here be correct? */
 542                 if (!NT_STATUS_IS_OK(status)) {
 543                         talloc_free(sd);
 544                         return NULL;
 545                 }
 546         }
 547
 548         return sd;
 549 }
 550
 551 struct security_descriptor *security_descriptor_append(struct security_descriptor *sd,
 552                                                        ...)
 553 {
 554         va_list ap;
 555
 556         va_start(ap, sd);
 557         sd = security_descriptor_appendv(sd, false, ap);
 558         va_end(ap);
 559
 560         return sd;
 561 }
 562
 563 static struct security_descriptor *security_descriptor_createv(TALLOC_CTX *mem_ctx,
 564                                                                uint16_t sd_type,
 565                                                                const char *owner_sid,
 566                                                                const char *group_sid,
 567                                                                bool add_ace_to_sacl,
 568                                                                va_list ap)
 569 {
 570         struct security_descriptor *sd;
 571
 572         sd = security_descriptor_initialise(mem_ctx);
 573         if (sd == NULL) {
 574                 return NULL;
 575         }
 576
 577         sd->type |= sd_type;
 578
 579         if (owner_sid) {
 580                 sd->owner_sid = dom_sid_parse_talloc(sd, owner_sid);
 581                 if (sd->owner_sid == NULL) {
 582                         talloc_free(sd);
 583                         return NULL;
 584                 }
 585         }
 586         if (group_sid) {
 587                 sd->group_sid = dom_sid_parse_talloc(sd, group_sid);
 588                 if (sd->group_sid == NULL) {
 589                         talloc_free(sd);
 590                         return NULL;
 591                 }
 592         }
 593
 594         return security_descriptor_appendv(sd, add_ace_to_sacl, ap);
 595 }
 596
 597 /*
 598   create a security descriptor using string SIDs. This is used by the
 599   torture code to allow the easy creation of complex ACLs
 600   This is a varargs function. The list of DACL ACEs ends with a NULL sid.
 601
 602   Each ACE contains a set of 4 parameters:
 603   SID, ACCESS_TYPE, MASK, FLAGS
 604
 605   a typical call would be:
 606
 607     sd = security_descriptor_dacl_create(mem_ctx,
 608                                          sd_type_flags,
 609                                          mysid,
 610                                          mygroup,
 611                                          SID_NT_AUTHENTICATED_USERS,
 612                                          SEC_ACE_TYPE_ACCESS_ALLOWED,
 613                                          SEC_FILE_ALL,
 614                                          SEC_ACE_FLAG_OBJECT_INHERIT,
 615                                          NULL);
 616   that would create a sd with one DACL ACE
 617 */
 618
 619 struct security_descriptor *security_descriptor_dacl_create(TALLOC_CTX *mem_ctx,
 620                                                             uint16_t sd_type,
 621                                                             const char *owner_sid,
 622                                                             const char *group_sid,
 623                                                             ...)
 624 {
 625         struct security_descriptor *sd = NULL;
 626         va_list ap;
 627         va_start(ap, group_sid);
 628         sd = security_descriptor_createv(mem_ctx, sd_type, owner_sid,
 629                                          group_sid, false, ap);
 630         va_end(ap);
 631
 632         return sd;
 633 }
 634
 635 struct security_descriptor *security_descriptor_sacl_create(TALLOC_CTX *mem_ctx,
 636                                                             uint16_t sd_type,
 637                                                             const char *owner_sid,
 638                                                             const char *group_sid,
 639                                                             ...)
 640 {
 641         struct security_descriptor *sd = NULL;
 642         va_list ap;
 643         va_start(ap, group_sid);
 644         sd = security_descriptor_createv(mem_ctx, sd_type, owner_sid,
 645                                          group_sid, true, ap);
 646         va_end(ap);
 647
 648         return sd;
 649 }
 650
 651 struct security_ace *security_ace_create(TALLOC_CTX *mem_ctx,
 652                                          const char *sid_str,
 653                                          enum security_ace_type type,
 654                                          uint32_t access_mask,
 655                                          uint8_t flags)
 656
 657 {
 658         struct security_ace *ace;
 659         bool ok;
 660
 661         ace = talloc_zero(mem_ctx, struct security_ace);
 662         if (ace == NULL) {
 663                 return NULL;
 664         }
 665
 666         ok = dom_sid_parse(sid_str, &ace->trustee);
 667         if (!ok) {
 668                 talloc_free(ace);
 669                 return NULL;
 670         }
 671         ace->type = type;
 672         ace->access_mask = access_mask;
 673         ace->flags = flags;
 674
 675         return ace;
 676 }
 677
 678 /*******************************************************************
 679  Check for MS NFS ACEs in a sd
 680 *******************************************************************/
 681 bool security_descriptor_with_ms_nfs(const struct security_descriptor *psd)
 682 {
 683         int i;
 684
 685         if (psd->dacl == NULL) {
 686                 return false;
 687         }
 688
 689         for (i = 0; i < psd->dacl->num_aces; i++) {
 690                 if (dom_sid_compare_domain(
 691                             &global_sid_Unix_NFS,
 692                             &psd->dacl->aces[i].trustee) == 0) {
 693                         return true;
 694                 }
 695         }
 696
 697         return false;
 698 }