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
  32 /* Todos:
  33  * build the security token dacl as follows:
  34  * SYSTEM: GA, OWNER: GA, LOGIN_SID:GW|GE
  35  * Need session id information for the login SID. Probably
  36  * the best place for this is during token creation
  37  *
  38  * Implement SD Invariants
  39  * ACE sorting rules
  40  * LDAP_SERVER_SD_FLAGS_OID control
  41  * ADTS 7.1.3.3 needs to be clarified
  42  */
  43
  44 /* the mapping function for generic rights for DS.(GA,GR,GW,GX)
  45  * The mapping function is passed as an argument to the
  46  * descriptor calculating routine and depends on the security
  47  * manager that calls the calculating routine.
  48  * TODO: need similar mappings for the file system and
  49  * registry security managers in order to make this code
  50  * generic for all security managers
  51  */
  52
  53 uint32_t map_generic_rights_ds(uint32_t access_mask)
  54 {
  55         if (access_mask & SEC_GENERIC_ALL){
  56                 access_mask |= SEC_ADS_GENERIC_ALL;
  57                 access_mask = ~SEC_GENERIC_ALL;
  58         }
  59
  60         if (access_mask & SEC_GENERIC_EXECUTE){
  61                 access_mask |= SEC_ADS_GENERIC_EXECUTE;
  62                 access_mask = ~SEC_GENERIC_EXECUTE;
  63         }
  64
  65         if (access_mask & SEC_GENERIC_WRITE){
  66                 access_mask |= SEC_ADS_GENERIC_WRITE;
  67                 access_mask &= ~SEC_GENERIC_WRITE;
  68         }
  69
  70         if (access_mask & SEC_GENERIC_READ){
  71                 access_mask |= SEC_ADS_GENERIC_READ;
  72                 access_mask &= ~SEC_GENERIC_READ;
  73         }
  74
  75         return access_mask;
  76 }
  77
  78 /* Not sure what this has to be,
  79 * and it does not seem to have any influence */
  80 static bool object_in_list(struct GUID *object_list, struct GUID *object)
  81 {
  82         return true;
  83 }
  84
  85
  86 static bool contains_inheritable_aces(struct security_acl *acl)
  87 {
  88         int i;
  89         if (!acl)
  90                 return false;
  91
  92         for (i=0; i < acl->num_aces; i++) {
  93                 struct security_ace *ace = &acl->aces[i];
  94                 if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
  95                     (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
  96                         return true;
  97         }
  98
  99         return false;
 100 }
 101
 102 static struct security_acl *preprocess_creator_acl(TALLOC_CTX *mem, struct security_acl *acl)
 103 {
 104         int i;
 105         struct security_acl *new_acl = talloc_zero(mem, struct security_acl);
 106
 107         new_acl->revision = acl->revision;
 108         for (i=0; i < acl->num_aces; i++) {
 109                 struct security_ace *ace = &acl->aces[i];
 110                 if (!(ace->flags & SEC_ACE_FLAG_INHERITED_ACE)){
 111                         new_acl->aces = talloc_realloc(new_acl, new_acl->aces, struct security_ace,
 112                                            new_acl->num_aces+1);
 113                         if (new_acl->aces == NULL) {
 114                                 talloc_free(new_acl);
 115                                 return NULL;
 116                         }
 117                         new_acl->aces[new_acl->num_aces] = *ace;
 118                         /*memcpy(&new_acl->aces[new_acl->num_aces], ace,
 119                           sizeof(struct security_ace)); */
 120                         new_acl->num_aces++;
 121                 }
 122         }
 123         if (new_acl)
 124                 new_acl->revision = acl->revision;
 125         /* Todo what to do if all were inherited and this is empty */
 126         return new_acl;
 127 }
 128
 129 /* This is not exactly as described in the docs. The original seemed to return
 130  * only a list of the inherited or flagless ones... */
 131
 132 static bool postprocess_acl(struct security_acl *acl,
 133                             struct dom_sid *owner,
 134                             struct dom_sid *group,
 135                             uint32_t (*generic_map)(uint32_t access_mask))
 136 {
 137         int i;
 138         struct dom_sid *co, *cg;
 139         TALLOC_CTX *tmp_ctx = talloc_new(acl);
 140         if (!generic_map){
 141                 return false;
 142         }
 143         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 144         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 145         for (i=0; i < acl->num_aces; i++){
 146                 struct security_ace *ace = &acl->aces[i];
 147                 if (!(ace->flags == 0 || ace->flags & SEC_ACE_FLAG_INHERITED_ACE))
 148                         continue;
 149                 if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY)
 150                         continue;
 151                 if (dom_sid_equal(&ace->trustee, co)){
 152                         ace->trustee = *owner;
 153                         /* perhaps this should be done somewhere else? */
 154                         ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 155                 }
 156                 if (dom_sid_equal(&ace->trustee, cg)){
 157                         ace->trustee = *group;
 158                         ace->flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 159                 }
 160                 ace->access_mask = generic_map(ace->access_mask);
 161         }
 162
 163         talloc_free(tmp_ctx);
 164         return true;
 165 }
 166
 167 static struct security_acl *calculate_inherited_from_parent(TALLOC_CTX *mem_ctx,
 168                                                 struct security_acl *acl,
 169                                                 bool is_container,
 170                                                 struct GUID *object_list)
 171 {
 172         int i;
 173         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 174         struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
 175         struct security_acl *inh_acl = talloc_zero(tmp_ctx, struct security_acl);
 176         struct security_acl *new_acl;
 177         struct dom_sid *co, *cg;
 178         if (!tmp_acl || !inh_acl)
 179                 return NULL;
 180
 181         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 182         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 183
 184         for (i=0; i < acl->num_aces; i++){
 185                 struct security_ace *ace = &acl->aces[i];
 186                 if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY)
 187                         continue;
 188
 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 *inh_acl = talloc_zero(tmp_ctx, struct security_acl); */
 258         struct security_acl *new_acl;
 259         struct dom_sid *co, *cg;
 260
 261         if (!tmp_acl)
 262                 return NULL;
 263
 264         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 265         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 266
 267         for (i=0; i < acl->num_aces; i++){
 268                 struct security_ace *ace = &acl->aces[i];
 269                 if (ace->flags & SEC_ACE_FLAG_INHERITED_ACE)
 270                         continue;
 271
 272                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 273                                               tmp_acl->num_aces+1);
 274                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 275                 tmp_acl->aces[tmp_acl->num_aces].flags  = 0;
 276                 tmp_acl->num_aces++;
 277
 278                 if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
 279                         continue;
 280
 281                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 282                                                tmp_acl->num_aces+1);
 283                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 284                 tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 285                 tmp_acl->num_aces++;
 286         }
 287         new_acl = security_acl_dup(mem_ctx,tmp_acl);
 288
 289         talloc_free(tmp_ctx);
 290         return new_acl;
 291 }
 292
 293 static bool compute_acl(int acl_type,
 294                         struct security_descriptor *parent_sd,
 295                         struct security_descriptor *creator_sd,
 296                         bool is_container,
 297                         uint32_t inherit_flags,
 298                         struct GUID *object_list,
 299                         uint32_t (*generic_map)(uint32_t access_mask),
 300                         struct security_token *token,
 301                         struct security_descriptor *new_sd) /* INOUT argument */
 302 {
 303         struct security_acl *p_acl = NULL, *c_acl = NULL, **new_acl;
 304         if (acl_type == SEC_DESC_DACL_PRESENT){
 305                 if (parent_sd)
 306                         p_acl = parent_sd->dacl;
 307                 if (creator_sd)
 308                         c_acl = creator_sd->dacl;
 309                 new_acl = &new_sd->dacl;
 310         }
 311         else{
 312                 if (parent_sd)
 313                         p_acl = parent_sd->sacl;
 314                 if (creator_sd)
 315                         c_acl = creator_sd->sacl;
 316                 new_acl = &new_sd->sacl;
 317         }
 318         if (contains_inheritable_aces(p_acl)){
 319                 if (!c_acl || (c_acl && inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
 320                         *new_acl = calculate_inherited_from_parent(new_sd,
 321                                                        p_acl,
 322                                                        is_container,
 323                                                        object_list);
 324                         if (*new_acl == NULL)
 325                                 goto final;
 326                         if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 327                                              new_sd->group_sid, generic_map))
 328                                 return false;
 329                         else
 330                                 goto final;
 331                 }
 332                 if (c_acl && !(inherit_flags & SEC_DEFAULT_DESCRIPTOR)){
 333                         struct security_acl *pr_acl, *tmp_acl, *tpr_acl;
 334                         tpr_acl = preprocess_creator_acl(new_sd, c_acl);
 335                         tmp_acl = calculate_inherited_from_creator(new_sd,
 336                                                       tpr_acl,
 337                                                       is_container,
 338                                                       object_list);
 339                         /* Todo some refactoring here! */
 340                         if (acl_type == SEC_DESC_DACL_PRESENT &&
 341                             !(creator_sd->type & SECINFO_PROTECTED_DACL) &&
 342                             (inherit_flags & SEC_DACL_AUTO_INHERIT)){
 343                                 pr_acl = calculate_inherited_from_parent(new_sd,
 344                                                              p_acl,
 345                                                              is_container,
 346                                                              object_list);
 347
 348                                 *new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
 349                                 new_sd->type |= SEC_DESC_DACL_AUTO_INHERITED;
 350                         }
 351                         else if (acl_type == SEC_DESC_SACL_PRESENT &&
 352                             !(creator_sd->type & SECINFO_PROTECTED_SACL) &&
 353                             (inherit_flags & SEC_SACL_AUTO_INHERIT)){
 354                                 pr_acl = calculate_inherited_from_parent(new_sd,
 355                                                              p_acl,
 356                                                              is_container,
 357                                                              object_list);
 358
 359                                 *new_acl = security_acl_concatenate(new_sd, tmp_acl, pr_acl);
 360                                 new_sd->type |= SEC_DESC_SACL_AUTO_INHERITED;
 361                         }
 362                 }
 363                 if (*new_acl == NULL)
 364                         goto final;
 365                 if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 366                                      new_sd->group_sid,generic_map))
 367                         return false;
 368                 else
 369                         goto final;
 370         }
 371         else{
 372                 if (!c_acl){
 373                         if (acl_type == SEC_DESC_DACL_PRESENT && token->default_dacl)
 374                                 *new_acl = security_acl_dup(new_sd, token->default_dacl);
 375                 }
 376                 else{
 377                         *new_acl = preprocess_creator_acl(new_sd,c_acl);
 378                         if (*new_acl == NULL)
 379                                 goto final;
 380                         if (!postprocess_acl(*new_acl, new_sd->owner_sid,
 381                                              new_sd->group_sid,generic_map))
 382                                 return false;
 383                         else
 384                                 goto final;
 385                 }
 386         }
 387 final:
 388         if (acl_type == SEC_DESC_DACL_PRESENT && new_sd->dacl)
 389                 new_sd->type |= SEC_DESC_DACL_PRESENT;
 390
 391         if (acl_type == SEC_DESC_SACL_PRESENT && new_sd->sacl)
 392                 new_sd->type |= SEC_DESC_SACL_PRESENT;
 393         /* This is a hack to handle the fact that
 394          * apprantly any AI flag provided by the user is preserved */
 395         if (creator_sd)
 396                 new_sd->type |= creator_sd->type;
 397         return true;
 398 }
 399
 400 struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx,
 401                                                        struct security_descriptor *parent_sd,
 402                                                        struct security_descriptor *creator_sd,
 403                                                        bool is_container,
 404                                                        struct GUID *object_list,
 405                                                        uint32_t inherit_flags,
 406                                                        struct security_token *token,
 407                                                        struct dom_sid *default_owner, /* valid only for DS, NULL for the other RSs */
 408                                                        struct dom_sid *default_group, /* valid only for DS, NULL for the other RSs */
 409                                                        uint32_t (*generic_map)(uint32_t access_mask))
 410 {
 411         struct security_descriptor *new_sd;
 412         struct dom_sid *new_owner = NULL;
 413         struct dom_sid *new_group = NULL;
 414
 415         new_sd = security_descriptor_initialise(mem_ctx);
 416         if (!new_sd)
 417                 return NULL;
 418         if (!creator_sd || !creator_sd->owner_sid){
 419                 if (inherit_flags & SEC_OWNER_FROM_PARENT)
 420                         new_owner = parent_sd->owner_sid;
 421                 else if (!default_owner)
 422                         new_owner = token->user_sid;
 423                 else
 424                         new_owner = default_owner;
 425         }
 426         else
 427                 new_owner = creator_sd->owner_sid;
 428
 429         if (!creator_sd || !creator_sd->group_sid){
 430                 if (inherit_flags & SEC_GROUP_FROM_PARENT && parent_sd)
 431                         new_group = parent_sd->group_sid;
 432                 else if (!default_group)
 433                         new_group = token->group_sid;
 434                 else new_group = default_group;
 435         }
 436         else
 437                 new_group = creator_sd->group_sid;
 438
 439         new_sd->owner_sid = talloc_memdup(new_sd, new_owner, sizeof(struct dom_sid));
 440         new_sd->group_sid = talloc_memdup(new_sd, new_group, sizeof(struct dom_sid));
 441         if (!new_sd->owner_sid || !new_sd->group_sid){
 442                 talloc_free(new_sd);
 443                 return NULL;
 444         }
 445
 446         if (!compute_acl(SEC_DESC_DACL_PRESENT, parent_sd, creator_sd,
 447                          is_container, inherit_flags, object_list,
 448                          generic_map,token,new_sd)){
 449                 talloc_free(new_sd);
 450                 return NULL;
 451         }
 452
 453         if (!compute_acl(SEC_DESC_SACL_PRESENT, parent_sd, creator_sd,
 454                          is_container, inherit_flags, object_list,
 455                          generic_map, token,new_sd)){
 456                 talloc_free(new_sd);
 457                 return NULL;
 458         }
 459
 460         return new_sd;
 461 }