source4/libcli/security/create_descriptor.c

   1 /*
   2    Copyright (C) Nadezhda Ivanova 2009
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 /*
  19  *  Name: create_descriptor
  20  *
  21  *  Component: routines for calculating and creating security descriptors
  22  *  as described in MS-DTYP 2.5.2.2
  23  *
  24  *  Description:
  25  *
  26  *
  27  *  Author: Nadezhda Ivanova
  28  */
  29 #include "includes.h"
  30 #include "libcli/security/security.h"
  31 #include "librpc/gen_ndr/ndr_security.h"
  32
  33 /* Todos:
  34  * build the security token dacl as follows:
  35  * SYSTEM: GA, OWNER: GA, LOGIN_SID:GW|GE
  36  * Need session id information for the login SID. Probably
  37  * the best place for this is during token creation
  38  *
  39  * Implement SD Invariants
  40  * ACE sorting rules
  41  * LDAP_SERVER_SD_FLAGS_OID control
  42  * ADTS 7.1.3.3 needs to be clarified
  43  */
  44
  45 /* the mapping function for generic rights for DS.(GA,GR,GW,GX)
  46  * The mapping function is passed as an argument to the
  47  * descriptor calculating routine and depends on the security
  48  * manager that calls the calculating routine.
  49  * TODO: need similar mappings for the file system and
  50  * registry security managers in order to make this code
  51  * generic for all security managers
  52  */
  53
  54 uint32_t map_generic_rights_ds(uint32_t access_mask)
  55 {
  56         if (access_mask & SEC_GENERIC_ALL){
  57                 access_mask |= SEC_ADS_GENERIC_ALL;
  58                 access_mask = ~SEC_GENERIC_ALL;
  59         }
  60
  61         if (access_mask & SEC_GENERIC_EXECUTE){
  62                 access_mask |= SEC_ADS_GENERIC_EXECUTE;
  63                 access_mask = ~SEC_GENERIC_EXECUTE;
  64         }
  65
  66         if (access_mask & SEC_GENERIC_WRITE){
  67                 access_mask |= SEC_ADS_GENERIC_WRITE;
  68                 access_mask &= ~SEC_GENERIC_WRITE;
  69         }
  70
  71         if (access_mask & SEC_GENERIC_READ){
  72                 access_mask |= SEC_ADS_GENERIC_READ;
  73                 access_mask &= ~SEC_GENERIC_READ;
  74         }
  75
  76         return access_mask;
  77 }
  78
  79 /* Not sure what this has to be,
  80 * and it does not seem to have any influence */
  81 static bool object_in_list(struct GUID *object_list, struct GUID *object)
  82 {
  83         return true;
  84 }
  85
  86
  87 static bool contains_inheritable_aces(struct security_acl *acl)
  88 {
  89         int i;
  90         if (!acl)
  91                 return false;
  92
  93         for (i=0; i < acl->num_aces; i++) {
  94                 struct security_ace *ace = &acl->aces[i];
  95                 if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
  96                     (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
  97                         return true;
  98         }
  99
 100         return false;
 101 }
 102
 103 static struct security_acl *preprocess_creator_acl(TALLOC_CTX *mem, struct security_acl *acl)
 104 {
 105         int i;
 106         struct security_acl *new_acl;
 107         if (!acl) {
 108                 return NULL;
 109         }
 110
 111         new_acl = talloc_zero(mem, struct security_acl);
 112
 113         for (i=0; i < acl->num_aces; i++) {
 114                 struct security_ace *ace = &acl->aces[i];
 115                 if (!(ace->flags & SEC_ACE_FLAG_INHERITED_ACE)){
 116                         new_acl->aces = talloc_realloc(new_acl, new_acl->aces, struct security_ace,
 117                                            new_acl->num_aces+1);
 118                         if (new_acl->aces == NULL) {
 119                                 talloc_free(new_acl);
 120                                 return NULL;
 121                         }
 122                         new_acl->aces[new_acl->num_aces] = *ace;
 123                         new_acl->num_aces++;
 124                 }
 125         }
 126         if (new_acl)
 127                 new_acl->revision = acl->revision;
 128
 129         return new_acl;
 130 }
 131
 132 /* This is not exactly as described in the docs. The original seemed to return
 133  * only a list of the inherited or flagless ones... */
 134
 135 static bool postprocess_acl(struct security_acl *acl,
 136                             struct dom_sid *owner,
 137                             struct dom_sid *group,
 138                             uint32_t (*generic_map)(uint32_t access_mask))
 139 {
 140         int i;
 141         struct dom_sid *co, *cg;
 142         TALLOC_CTX *tmp_ctx = talloc_new(acl);
 143         if (!generic_map){
 144                 return false;
 145         }
 146         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 147         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 148         for (i=0; i < acl->num_aces; i++){
 149                 struct security_ace *ace = &acl->aces[i];
 150                 if (!(ace->flags == 0 || ace->flags & SEC_ACE_FLAG_INHERITED_ACE))
 151                         continue;
 152                 if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY)
 153                         continue;
 154                 if (dom_sid_equal(&ace->trustee, co)){
 155                         ace->trustee = *owner;
 156                         /* perhaps this should be done somewhere else? */
 157                         ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 158                 }
 159                 if (dom_sid_equal(&ace->trustee, cg)){
 160                         ace->trustee = *group;
 161                         ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 162                 }
 163                 ace->access_mask = generic_map(ace->access_mask);
 164         }
 165
 166         talloc_free(tmp_ctx);
 167         return true;
 168 }
 169
 170 static struct security_acl *calculate_inherited_from_parent(TALLOC_CTX *mem_ctx,
 171                                                 struct security_acl *acl,
 172                                                 bool is_container,
 173                                                 struct GUID *object_list)
 174 {
 175         int i;
 176         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 177         struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
 178         struct security_acl *inh_acl = talloc_zero(tmp_ctx, struct security_acl);
 179         struct security_acl *new_acl;
 180         struct dom_sid *co, *cg;
 181         if (!tmp_acl || !inh_acl)
 182                 return NULL;
 183
 184         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 185         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 186
 187         for (i=0; i < acl->num_aces; i++){
 188                 struct security_ace *ace = &acl->aces[i];
 189                 if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
 190                     (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)){
 191                         tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 192                                                        tmp_acl->num_aces+1);
 193                         if (tmp_acl->aces == NULL) {
 194                                 talloc_free(tmp_ctx);
 195                                 return NULL;
 196                         }
 197
 198                         tmp_acl->aces[tmp_acl->num_aces] = *ace;
 199                         tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
 200
 201                         if (is_container && (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
 202                             tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 203
 204                         if (ace->type == SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT ||
 205                             ace->type == SEC_ACE_TYPE_ACCESS_DENIED_OBJECT){
 206                                 if (!object_in_list(object_list, &ace->object.object.type.type)){
 207                                         tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 208                                 }
 209
 210                         }
 211                         tmp_acl->num_aces++;
 212                 }
 213         }
 214
 215         if (is_container){
 216                 for (i=0; i < acl->num_aces; i++){
 217                         struct security_ace *ace = &acl->aces[i];
 218
 219                         if (ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT)
 220                                 continue;
 221                         if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
 222                                 continue;
 223
 224                         if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
 225                             (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)){
 226                                 inh_acl->aces = talloc_realloc(inh_acl, inh_acl->aces, struct security_ace,
 227                                                                inh_acl->num_aces+1);
 228                                 if (inh_acl->aces == NULL){
 229                                         talloc_free(tmp_ctx);
 230                                         return NULL;
 231                                 }
 232                                 inh_acl->aces[inh_acl->num_aces] = *ace;
 233                                 inh_acl->aces[inh_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 234                                 inh_acl->aces[inh_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
 235                                 inh_acl->num_aces++;
 236                         }
 237                 }
 238         }
 239         new_acl = security_acl_concatenate(mem_ctx,tmp_acl, inh_acl);
 240         if (new_acl)
 241                 new_acl->revision = acl->revision;
 242         talloc_free(tmp_ctx);
 243         return new_acl;
 244 }
 245
 246 /* In the docs this looks == calculate_inherited_from_parent. However,
 247  * It shouldn't return the inherited, rather filter them out....
 248  */
 249 static struct security_acl *calculate_inherited_from_creator(TALLOC_CTX *mem_ctx,
 250                                                 struct security_acl *acl,
 251                                                 bool is_container,
 252                                                 struct GUID *object_list)
 253 {
 254         int i;
 255         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 256         struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
 257         struct security_acl *new_acl;
 258         struct dom_sid *co, *cg;
 259
 260         if (!tmp_acl)
 261                 return NULL;
 262
 263         tmp_acl->revision = acl->revision;
 264         DEBUG(6,(__location__ ": acl revision %u\n", acl->revision));
 265
 266         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 267         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 268
 269         for (i=0; i < acl->num_aces; i++){
 270                 struct security_ace *ace = &acl->aces[i];
 271                 if (ace->flags & SEC_ACE_FLAG_INHERITED_ACE)
 272                         continue;
 273
 274                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 275                                               tmp_acl->num_aces+1);
 276                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 277                 tmp_acl->num_aces++;
 278
 279                 if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
 280                         continue;
 281
 282                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 283                                                tmp_acl->num_aces+1);
 284                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 285                 tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 286                 tmp_acl->num_aces++;
 287         }
 288         new_acl = security_acl_dup(mem_ctx,tmp_acl);
 289
 290         if (new_acl)
 291                 new_acl->revision = acl->revision;
 292
 293         talloc_free(tmp_ctx);
 294         return new_acl;
 295 }
 296
 297 static void cr_descr_log_descriptor(struct security_descriptor *sd,
 298                                     const char *message,
 299                                     int level)
 300 {
 301         if (sd) {
 302                 DEBUG(level,("%s: %s\n", message,
 303                              ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_descriptor,
 304                                                      "", sd)));
 305         }
 306         else {
 307                 DEBUG(level,("%s: NULL\n", message));
 308         }
 309 }
 310
 311 static void cr_descr_log_acl(struct security_acl *acl,
 312                                     const char *message,
 313                                     int level)
 314 {
 315         if (acl) {
 316                 DEBUG(level,("%s: %s\n", message,
 317                              ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_acl,
 318                                                      "", acl)));
 319         }
 320         else {
 321                 DEBUG(level,("%s: NULL\n", message));
 322         }
 323 }
 324
 325 static bool compute_acl(int acl_type,
 326                         struct security_descriptor *parent_sd,
 327                         struct security_descriptor *creator_sd,
 328                         bool is_container,
 329                         uint32_t inherit_flags,
 330                         struct GUID *object_list,
 331                         uint32_t (*generic_map)(uint32_t access_mask),
 332                         struct security_token *token,
 333                         struct security_descriptor *new_sd) /* INOUT argument */
 334 {
 335         struct security_acl *p_acl = NULL, *c_acl = NULL, **new_acl;
 336         int level = 10;
 337         if (acl_type == SEC_DESC_DACL_PRESENT){
 338                 if (parent_sd)
 339                         p_acl = parent_sd->dacl;
 340                 if (creator_sd)
 341                         c_acl = creator_sd->dacl;
 342                 new_acl = &new_sd->dacl;
 343         }
 344         else{
 345                 if (parent_sd)
 346                         p_acl = parent_sd->sacl;
 347                 if (creator_sd)
 348                         c_acl = creator_sd->sacl;
 349                 new_acl = &new_sd->sacl;
 350         }
 351
 352         cr_descr_log_descriptor(parent_sd, __location__"parent_sd", level);
 353         cr_descr_log_descriptor(creator_sd,__location__ "creator_sd", level);
 354
 355         if (contains_inheritable_aces(p_acl)){
 356                 if (!c_acl || (c_acl && inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
 357                         *new_acl = calculate_inherited_from_parent(new_sd,
 358                                                        p_acl,
 359                                                        is_container,
 360                                                        object_list);
 361                         if (*new_acl == NULL)
 362                                 goto final;
 363                         if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 364                                              new_sd->group_sid, generic_map))
 365                                 return false;
 366                         else {
 367                                 cr_descr_log_descriptor(new_sd,
 368                                                         __location__": Nothing from creator, newsd is", level);
 369                                 goto final;
 370                         }
 371                 }
 372                 if (c_acl && !(inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
 373                         struct security_acl *pr_acl, *tmp_acl, *tpr_acl;
 374                         tpr_acl = preprocess_creator_acl(new_sd, c_acl);
 375                         tmp_acl = calculate_inherited_from_creator(new_sd,
 376                                                       tpr_acl,
 377                                                       is_container,
 378                                                       object_list);
 379
 380                         cr_descr_log_acl(tmp_acl, __location__"Inherited from creator", level);
 381                         /* Todo some refactoring here! */
 382                         if (acl_type == SEC_DESC_DACL_PRESENT &&
 383                             !(creator_sd->type & SECINFO_PROTECTED_DACL) &&
 384                             (inherit_flags & SEC_DACL_AUTO_INHERIT)){
 385                                 pr_acl = calculate_inherited_from_parent(new_sd,
 386                                                              p_acl,
 387                                                              is_container,
 388                                                              object_list);
 389                                 cr_descr_log_acl(pr_acl, __location__"Inherited from parent", level);
 390                                 *new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
 391                                 new_sd->type |= SEC_DESC_DACL_AUTO_INHERITED;
 392                         }
 393                         else if (acl_type == SEC_DESC_SACL_PRESENT &&
 394                             !(creator_sd->type & SECINFO_PROTECTED_SACL) &&
 395                             (inherit_flags & SEC_SACL_AUTO_INHERIT)){
 396                                 pr_acl = calculate_inherited_from_parent(new_sd,
 397                                                              p_acl,
 398                                                              is_container,
 399                                                              object_list);
 400                                 cr_descr_log_acl(pr_acl, __location__"Inherited from parent", level);
 401                                 *new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
 402                                 new_sd->type |= SEC_DESC_SACL_AUTO_INHERITED;
 403                         }
 404                 }
 405                 if (*new_acl == NULL)
 406                         goto final;
 407                 if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 408                                      new_sd->group_sid,generic_map))
 409                         return false;
 410                 else
 411                         goto final;
 412         }
 413         else{
 414                 *new_acl = preprocess_creator_acl(new_sd,c_acl);
 415                 if (*new_acl == NULL)
 416                         goto final;
 417                 if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 418                                      new_sd->group_sid,generic_map))
 419                         return false;
 420                 else
 421                         goto final;
 422         }
 423 final:
 424         if (acl_type == SEC_DESC_DACL_PRESENT && new_sd->dacl)
 425                 new_sd->type |= SEC_DESC_DACL_PRESENT;
 426
 427         if (acl_type == SEC_DESC_SACL_PRESENT && new_sd->sacl)
 428                 new_sd->type |= SEC_DESC_SACL_PRESENT;
 429         /* This is a hack to handle the fact that
 430          * apprantly any AI flag provided by the user is preserved */
 431         if (creator_sd)
 432                 new_sd->type |= creator_sd->type;
 433         cr_descr_log_descriptor(new_sd, __location__"final sd", level);
 434         return true;
 435 }
 436
 437 struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx,
 438                                                        struct security_descriptor *parent_sd,
 439                                                        struct security_descriptor *creator_sd,
 440                                                        bool is_container,
 441                                                        struct GUID *object_list,
 442                                                        uint32_t inherit_flags,
 443                                                        struct security_token *token,
 444                                                        struct dom_sid *default_owner, /* valid only for DS, NULL for the other RSs */
 445                                                        struct dom_sid *default_group, /* valid only for DS, NULL for the other RSs */
 446                                                        uint32_t (*generic_map)(uint32_t access_mask))
 447 {
 448         struct security_descriptor *new_sd;
 449         struct dom_sid *new_owner = NULL;
 450         struct dom_sid *new_group = NULL;
 451
 452         new_sd = security_descriptor_initialise(mem_ctx);
 453         if (!new_sd) {
 454                 return NULL;
 455         }
 456
 457         if (!creator_sd || !creator_sd->owner_sid) {
 458                 if ((inherit_flags & SEC_OWNER_FROM_PARENT) && parent_sd) {
 459                         new_owner = parent_sd->owner_sid;
 460                 } else if (!default_owner) {
 461                         new_owner = token->user_sid;
 462                 } else {
 463                         new_owner = default_owner;
 464                         new_sd->type |= SEC_DESC_OWNER_DEFAULTED;
 465                 }
 466         } else {
 467                 new_owner = creator_sd->owner_sid;
 468         }
 469
 470         if (!creator_sd || !creator_sd->group_sid){
 471                 if ((inherit_flags & SEC_GROUP_FROM_PARENT) && parent_sd) {
 472                         new_group = parent_sd->group_sid;
 473                 } else if (!default_group) {
 474                         new_group = token->group_sid;
 475                 } else {
 476                         new_group = default_group;
 477                         new_sd->type |= SEC_DESC_GROUP_DEFAULTED;
 478                 }
 479         } else {
 480                 new_group = creator_sd->group_sid;
 481         }
 482
 483         new_sd->owner_sid = talloc_memdup(new_sd, new_owner, sizeof(struct dom_sid));
 484         new_sd->group_sid = talloc_memdup(new_sd, new_group, sizeof(struct dom_sid));
 485         if (!new_sd->owner_sid || !new_sd->group_sid){
 486                 talloc_free(new_sd);
 487                 return NULL;
 488         }
 489
 490         if (!compute_acl(SEC_DESC_DACL_PRESENT, parent_sd, creator_sd,
 491                          is_container, inherit_flags, object_list,
 492                          generic_map,token,new_sd)){
 493                 talloc_free(new_sd);
 494                 return NULL;
 495         }
 496
 497         if (!compute_acl(SEC_DESC_SACL_PRESENT, parent_sd, creator_sd,
 498                          is_container, inherit_flags, object_list,
 499                          generic_map, token,new_sd)){
 500                 talloc_free(new_sd);
 501                 return NULL;
 502         }
 503
 504         return new_sd;
 505 }