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         nacl = talloc (mem_ctx, struct security_acl);
  62         if (nacl == NULL) {
  63                 return NULL;
  64         }
  65
  66         nacl->aces = (struct security_ace *)talloc_memdup (nacl, oacl->aces, sizeof(struct security_ace) * oacl->num_aces);
  67         if ((nacl->aces == NULL) && (oacl->num_aces > 0)) {
  68                 goto failed;
  69         }
  70
  71         nacl->revision = oacl->revision;
  72         nacl->size = oacl->size;
  73         nacl->num_aces = oacl->num_aces;
  74
  75         return nacl;
  76
  77  failed:
  78         talloc_free (nacl);
  79         return NULL;
  80
  81 }
  82
  83 struct security_acl *security_acl_concatenate(TALLOC_CTX *mem_ctx,
  84                                               const struct security_acl *acl1,
  85                                               const struct security_acl *acl2)
  86 {
  87         struct security_acl *nacl;
  88         uint32_t i;
  89
  90         if (!acl1 && !acl2)
  91                 return NULL;
  92
  93         if (!acl1){
  94                 nacl = security_acl_dup(mem_ctx, acl2);
  95                 return nacl;
  96         }
  97
  98         if (!acl2){
  99                 nacl = security_acl_dup(mem_ctx, acl1);
 100                 return nacl;
 101         }
 102
 103         nacl = talloc (mem_ctx, struct security_acl);
 104         if (nacl == NULL) {
 105                 return NULL;
 106         }
 107
 108         nacl->revision = acl1->revision;
 109         nacl->size = acl1->size + acl2->size;
 110         nacl->num_aces = acl1->num_aces + acl2->num_aces;
 111
 112         if (nacl->num_aces == 0)
 113                 return nacl;
 114
 115         nacl->aces = (struct security_ace *)talloc_array (mem_ctx, struct security_ace, acl1->num_aces+acl2->num_aces);
 116         if ((nacl->aces == NULL) && (nacl->num_aces > 0)) {
 117                 goto failed;
 118         }
 119
 120         for (i = 0; i < acl1->num_aces; i++)
 121                 nacl->aces[i] = acl1->aces[i];
 122         for (i = 0; i < acl2->num_aces; i++)
 123                 nacl->aces[i + acl1->num_aces] = acl2->aces[i];
 124
 125         return nacl;
 126
 127  failed:
 128         talloc_free (nacl);
 129         return NULL;
 130
 131 }
 132
 133 /*
 134    talloc and copy a security descriptor
 135  */
 136 struct security_descriptor *security_descriptor_copy(TALLOC_CTX *mem_ctx,
 137                                                      const struct security_descriptor *osd)
 138 {
 139         struct security_descriptor *nsd;
 140
 141         nsd = talloc_zero(mem_ctx, struct security_descriptor);
 142         if (!nsd) {
 143                 return NULL;
 144         }
 145
 146         if (osd->owner_sid) {
 147                 nsd->owner_sid = dom_sid_dup(nsd, osd->owner_sid);
 148                 if (nsd->owner_sid == NULL) {
 149                         goto failed;
 150                 }
 151         }
 152
 153         if (osd->group_sid) {
 154                 nsd->group_sid = dom_sid_dup(nsd, osd->group_sid);
 155                 if (nsd->group_sid == NULL) {
 156                         goto failed;
 157                 }
 158         }
 159
 160         if (osd->sacl) {
 161                 nsd->sacl = security_acl_dup(nsd, osd->sacl);
 162                 if (nsd->sacl == NULL) {
 163                         goto failed;
 164                 }
 165         }
 166
 167         if (osd->dacl) {
 168                 nsd->dacl = security_acl_dup(nsd, osd->dacl);
 169                 if (nsd->dacl == NULL) {
 170                         goto failed;
 171                 }
 172         }
 173
 174         nsd->revision = osd->revision;
 175         nsd->type = osd->type;
 176
 177         return nsd;
 178
 179  failed:
 180         talloc_free(nsd);
 181
 182         return NULL;
 183 }
 184
 185 /*
 186   add an ACE to an ACL of a security_descriptor
 187 */
 188
 189 static NTSTATUS security_descriptor_acl_add(struct security_descriptor *sd,
 190                                             bool add_to_sacl,
 191                                             const struct security_ace *ace)
 192 {
 193         struct security_acl *acl = NULL;
 194
 195         if (add_to_sacl) {
 196                 acl = sd->sacl;
 197         } else {
 198                 acl = sd->dacl;
 199         }
 200
 201         if (acl == NULL) {
 202                 acl = talloc(sd, struct security_acl);
 203                 if (acl == NULL) {
 204                         return NT_STATUS_NO_MEMORY;
 205                 }
 206                 acl->revision = SECURITY_ACL_REVISION_NT4;
 207                 acl->size     = 0;
 208                 acl->num_aces = 0;
 209                 acl->aces     = NULL;
 210         }
 211
 212         acl->aces = talloc_realloc(acl, acl->aces,
 213                                    struct security_ace, acl->num_aces+1);
 214         if (acl->aces == NULL) {
 215                 return NT_STATUS_NO_MEMORY;
 216         }
 217
 218         acl->aces[acl->num_aces] = *ace;
 219
 220         switch (acl->aces[acl->num_aces].type) {
 221         case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT:
 222         case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT:
 223         case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT:
 224         case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT:
 225                 acl->revision = SECURITY_ACL_REVISION_ADS;
 226                 break;
 227         default:
 228                 break;
 229         }
 230
 231         acl->num_aces++;
 232
 233         if (add_to_sacl) {
 234                 sd->sacl = acl;
 235                 sd->type |= SEC_DESC_SACL_PRESENT;
 236         } else {
 237                 sd->dacl = acl;
 238                 sd->type |= SEC_DESC_DACL_PRESENT;
 239         }
 240
 241         return NT_STATUS_OK;
 242 }
 243
 244 /*
 245   add an ACE to the SACL of a security_descriptor
 246 */
 247
 248 NTSTATUS security_descriptor_sacl_add(struct security_descriptor *sd,
 249                                       const struct security_ace *ace)
 250 {
 251         return security_descriptor_acl_add(sd, true, ace);
 252 }
 253
 254 /*
 255   add an ACE to the DACL of a security_descriptor
 256 */
 257
 258 NTSTATUS security_descriptor_dacl_add(struct security_descriptor *sd,
 259                                       const struct security_ace *ace)
 260 {
 261         return security_descriptor_acl_add(sd, false, ace);
 262 }
 263
 264 /*
 265   delete the ACE corresponding to the given trustee in an ACL of a
 266   security_descriptor
 267 */
 268
 269 static NTSTATUS security_descriptor_acl_del(struct security_descriptor *sd,
 270                                             bool sacl_del,
 271                                             const struct dom_sid *trustee)
 272 {
 273         uint32_t i;
 274         bool found = false;
 275         struct security_acl *acl = NULL;
 276
 277         if (sacl_del) {
 278                 acl = sd->sacl;
 279         } else {
 280                 acl = sd->dacl;
 281         }
 282
 283         if (acl == NULL) {
 284                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 285         }
 286
 287         /* there can be multiple ace's for one trustee */
 288         for (i=0;i<acl->num_aces;i++) {
 289                 if (dom_sid_equal(trustee, &acl->aces[i].trustee)) {
 290                         memmove(&acl->aces[i], &acl->aces[i+1],
 291                                 sizeof(acl->aces[i]) * (acl->num_aces - (i+1)));
 292                         acl->num_aces--;
 293                         if (acl->num_aces == 0) {
 294                                 acl->aces = NULL;
 295                         }
 296                         found = true;
 297                 }
 298         }
 299
 300         if (!found) {
 301                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 302         }
 303
 304         acl->revision = SECURITY_ACL_REVISION_NT4;
 305
 306         for (i=0;i<acl->num_aces;i++) {
 307                 switch (acl->aces[i].type) {
 308                 case SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT:
 309                 case SEC_ACE_TYPE_ACCESS_DENIED_OBJECT:
 310                 case SEC_ACE_TYPE_SYSTEM_AUDIT_OBJECT:
 311                 case SEC_ACE_TYPE_SYSTEM_ALARM_OBJECT:
 312                         acl->revision = SECURITY_ACL_REVISION_ADS;
 313                         return NT_STATUS_OK;
 314                 default:
 315                         break; /* only for the switch statement */
 316                 }
 317         }
 318
 319         return NT_STATUS_OK;
 320 }
 321
 322 /*
 323   delete the ACE corresponding to the given trustee in the DACL of a
 324   security_descriptor
 325 */
 326
 327 NTSTATUS security_descriptor_dacl_del(struct security_descriptor *sd,
 328                                       const struct dom_sid *trustee)
 329 {
 330         return security_descriptor_acl_del(sd, false, trustee);
 331 }
 332
 333 /*
 334   delete the ACE corresponding to the given trustee in the SACL of a
 335   security_descriptor
 336 */
 337
 338 NTSTATUS security_descriptor_sacl_del(struct security_descriptor *sd,
 339                                       const struct dom_sid *trustee)
 340 {
 341         return security_descriptor_acl_del(sd, true, trustee);
 342 }
 343
 344 /*
 345   compare two security ace structures
 346 */
 347 bool security_ace_equal(const struct security_ace *ace1,
 348                         const struct security_ace *ace2)
 349 {
 350         if (ace1 == ace2) {
 351                 return true;
 352         }
 353         if ((ace1 == NULL) || (ace2 == NULL)) {
 354                 return false;
 355         }
 356         if (ace1->type != ace2->type) {
 357                 return false;
 358         }
 359         if (ace1->flags != ace2->flags) {
 360                 return false;
 361         }
 362         if (ace1->access_mask != ace2->access_mask) {
 363                 return false;
 364         }
 365         if (!dom_sid_equal(&ace1->trustee, &ace2->trustee)) {
 366                 return false;
 367         }
 368
 369         return true;
 370 }
 371
 372
 373 /*
 374   compare two security acl structures
 375 */
 376 bool security_acl_equal(const struct security_acl *acl1,
 377                         const struct security_acl *acl2)
 378 {
 379         uint32_t i;
 380
 381         if (acl1 == acl2) return true;
 382         if (!acl1 || !acl2) return false;
 383         if (acl1->revision != acl2->revision) return false;
 384         if (acl1->num_aces != acl2->num_aces) return false;
 385
 386         for (i=0;i<acl1->num_aces;i++) {
 387                 if (!security_ace_equal(&acl1->aces[i], &acl2->aces[i])) return false;
 388         }
 389         return true;
 390 }
 391
 392 /*
 393   compare two security descriptors.
 394 */
 395 bool security_descriptor_equal(const struct security_descriptor *sd1,
 396                                const struct security_descriptor *sd2)
 397 {
 398         if (sd1 == sd2) return true;
 399         if (!sd1 || !sd2) return false;
 400         if (sd1->revision != sd2->revision) return false;
 401         if (sd1->type != sd2->type) return false;
 402
 403         if (!dom_sid_equal(sd1->owner_sid, sd2->owner_sid)) return false;
 404         if (!dom_sid_equal(sd1->group_sid, sd2->group_sid)) return false;
 405         if (!security_acl_equal(sd1->sacl, sd2->sacl))      return false;
 406         if (!security_acl_equal(sd1->dacl, sd2->dacl))      return false;
 407
 408         return true;
 409 }
 410
 411 /*
 412   compare two security descriptors, but allow certain (missing) parts
 413   to be masked out of the comparison
 414 */
 415 bool security_descriptor_mask_equal(const struct security_descriptor *sd1,
 416                                     const struct security_descriptor *sd2,
 417                                     uint32_t mask)
 418 {
 419         if (sd1 == sd2) return true;
 420         if (!sd1 || !sd2) return false;
 421         if (sd1->revision != sd2->revision) return false;
 422         if ((sd1->type & mask) != (sd2->type & mask)) return false;
 423
 424         if (!dom_sid_equal(sd1->owner_sid, sd2->owner_sid)) return false;
 425         if (!dom_sid_equal(sd1->group_sid, sd2->group_sid)) return false;
 426         if ((mask & SEC_DESC_DACL_PRESENT) && !security_acl_equal(sd1->dacl, sd2->dacl))      return false;
 427         if ((mask & SEC_DESC_SACL_PRESENT) && !security_acl_equal(sd1->sacl, sd2->sacl))      return false;
 428
 429         return true;
 430 }
 431
 432
 433 static struct security_descriptor *security_descriptor_appendv(struct security_descriptor *sd,
 434                                                                bool add_ace_to_sacl,
 435                                                                va_list ap)
 436 {
 437         const char *sidstr;
 438
 439         while ((sidstr = va_arg(ap, const char *))) {
 440                 struct dom_sid *sid;
 441                 struct security_ace *ace = talloc_zero(sd, struct security_ace);
 442                 NTSTATUS status;
 443
 444                 if (ace == NULL) {
 445                         talloc_free(sd);
 446                         return NULL;
 447                 }
 448                 ace->type = va_arg(ap, unsigned int);
 449                 ace->access_mask = va_arg(ap, unsigned int);
 450                 ace->flags = va_arg(ap, unsigned int);
 451                 sid = dom_sid_parse_talloc(ace, sidstr);
 452                 if (sid == NULL) {
 453                         talloc_free(sd);
 454                         return NULL;
 455                 }
 456                 ace->trustee = *sid;
 457                 if (add_ace_to_sacl) {
 458                         status = security_descriptor_sacl_add(sd, ace);
 459                 } else {
 460                         status = security_descriptor_dacl_add(sd, ace);
 461                 }
 462                 /* TODO: check: would talloc_free(ace) here be correct? */
 463                 if (!NT_STATUS_IS_OK(status)) {
 464                         talloc_free(sd);
 465                         return NULL;
 466                 }
 467         }
 468
 469         return sd;
 470 }
 471
 472 struct security_descriptor *security_descriptor_append(struct security_descriptor *sd,
 473                                                        ...)
 474 {
 475         va_list ap;
 476
 477         va_start(ap, sd);
 478         sd = security_descriptor_appendv(sd, false, ap);
 479         va_end(ap);
 480
 481         return sd;
 482 }
 483
 484 static struct security_descriptor *security_descriptor_createv(TALLOC_CTX *mem_ctx,
 485                                                                uint16_t sd_type,
 486                                                                const char *owner_sid,
 487                                                                const char *group_sid,
 488                                                                bool add_ace_to_sacl,
 489                                                                va_list ap)
 490 {
 491         struct security_descriptor *sd;
 492
 493         sd = security_descriptor_initialise(mem_ctx);
 494         if (sd == NULL) {
 495                 return NULL;
 496         }
 497
 498         sd->type |= sd_type;
 499
 500         if (owner_sid) {
 501                 sd->owner_sid = dom_sid_parse_talloc(sd, owner_sid);
 502                 if (sd->owner_sid == NULL) {
 503                         talloc_free(sd);
 504                         return NULL;
 505                 }
 506         }
 507         if (group_sid) {
 508                 sd->group_sid = dom_sid_parse_talloc(sd, group_sid);
 509                 if (sd->group_sid == NULL) {
 510                         talloc_free(sd);
 511                         return NULL;
 512                 }
 513         }
 514
 515         return security_descriptor_appendv(sd, add_ace_to_sacl, ap);
 516 }
 517
 518 /*
 519   create a security descriptor using string SIDs. This is used by the
 520   torture code to allow the easy creation of complex ACLs
 521   This is a varargs function. The list of DACL ACEs ends with a NULL sid.
 522
 523   Each ACE contains a set of 4 parameters:
 524   SID, ACCESS_TYPE, MASK, FLAGS
 525
 526   a typical call would be:
 527
 528     sd = security_descriptor_dacl_create(mem_ctx,
 529                                          sd_type_flags,
 530                                          mysid,
 531                                          mygroup,
 532                                          SID_NT_AUTHENTICATED_USERS,
 533                                          SEC_ACE_TYPE_ACCESS_ALLOWED,
 534                                          SEC_FILE_ALL,
 535                                          SEC_ACE_FLAG_OBJECT_INHERIT,
 536                                          NULL);
 537   that would create a sd with one DACL ACE
 538 */
 539
 540 struct security_descriptor *security_descriptor_dacl_create(TALLOC_CTX *mem_ctx,
 541                                                             uint16_t sd_type,
 542                                                             const char *owner_sid,
 543                                                             const char *group_sid,
 544                                                             ...)
 545 {
 546         struct security_descriptor *sd = NULL;
 547         va_list ap;
 548         va_start(ap, group_sid);
 549         sd = security_descriptor_createv(mem_ctx, sd_type, owner_sid,
 550                                          group_sid, false, ap);
 551         va_end(ap);
 552
 553         return sd;
 554 }
 555
 556 struct security_descriptor *security_descriptor_sacl_create(TALLOC_CTX *mem_ctx,
 557                                                             uint16_t sd_type,
 558                                                             const char *owner_sid,
 559                                                             const char *group_sid,
 560                                                             ...)
 561 {
 562         struct security_descriptor *sd = NULL;
 563         va_list ap;
 564         va_start(ap, group_sid);
 565         sd = security_descriptor_createv(mem_ctx, sd_type, owner_sid,
 566                                          group_sid, true, ap);
 567         va_end(ap);
 568
 569         return sd;
 570 }
 571
 572 struct security_ace *security_ace_create(TALLOC_CTX *mem_ctx,
 573                                          const char *sid_str,
 574                                          enum security_ace_type type,
 575                                          uint32_t access_mask,
 576                                          uint8_t flags)
 577
 578 {
 579         struct security_ace *ace;
 580         bool ok;
 581
 582         ace = talloc_zero(mem_ctx, struct security_ace);
 583         if (ace == NULL) {
 584                 return NULL;
 585         }
 586
 587         ok = dom_sid_parse(sid_str, &ace->trustee);
 588         if (!ok) {
 589                 talloc_free(ace);
 590                 return NULL;
 591         }
 592         ace->type = type;
 593         ace->access_mask = access_mask;
 594         ace->flags = flags;
 595
 596         return ace;
 597 }
 598
 599 /*******************************************************************
 600  Check for MS NFS ACEs in a sd
 601 *******************************************************************/
 602 bool security_descriptor_with_ms_nfs(const struct security_descriptor *psd)
 603 {
 604         int i;
 605
 606         if (psd->dacl == NULL) {
 607                 return false;
 608         }
 609
 610         for (i = 0; i < psd->dacl->num_aces; i++) {
 611                 if (dom_sid_compare_domain(
 612                             &global_sid_Unix_NFS,
 613                             &psd->dacl->aces[i].trustee) == 0) {
 614                         return true;
 615                 }
 616         }
 617
 618         return false;
 619 }