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 2.5.3.x
  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 static struct security_acl *calculate_inherited_from_parent(TALLOC_CTX *mem_ctx,
  87                                                             struct security_acl *acl,
  88                                                             bool is_container,
  89                                                             struct dom_sid *owner,
  90                                                             struct dom_sid *group,
  91                                                             struct GUID *object_list)
  92 {
  93         uint32_t i;
  94         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
  95         struct security_acl *tmp_acl = talloc_zero(mem_ctx, struct security_acl);
  96         struct dom_sid *co, *cg;
  97         if (!tmp_acl) {
  98                 return NULL;
  99         }
 100
 101         if (!acl) {
 102                 return NULL;
 103         }
 104         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 105         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 106
 107         for (i=0; i < acl->num_aces; i++) {
 108                 struct security_ace *ace = &acl->aces[i];
 109                 if ((ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT) ||
 110                     (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT)) {
 111                         tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 112                                                        tmp_acl->num_aces+1);
 113                         if (tmp_acl->aces == NULL) {
 114                                 talloc_free(tmp_ctx);
 115                                 return NULL;
 116                         }
 117
 118                         tmp_acl->aces[tmp_acl->num_aces] = *ace;
 119                         tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
 120
 121                         if (is_container && (ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
 122                             tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 123
 124                         if (ace->type == SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT ||
 125                             ace->type == SEC_ACE_TYPE_ACCESS_DENIED_OBJECT) {
 126                                 if (!object_in_list(object_list, &ace->object.object.type.type)) {
 127                                         tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 128                                 }
 129
 130                         }
 131                         tmp_acl->aces[tmp_acl->num_aces].access_mask =
 132                                                     map_generic_rights_ds(ace->access_mask);
 133                         tmp_acl->num_aces++;
 134                         if (is_container) {
 135                                 if (!(ace->flags & SEC_ACE_FLAG_NO_PROPAGATE_INHERIT) &&
 136                                     ((dom_sid_equal(&ace->trustee, co) || dom_sid_equal(&ace->trustee, cg)))) {
 137                                             tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 138                                                                            tmp_acl->num_aces+1);
 139                                             if (tmp_acl->aces == NULL) {
 140                                                     talloc_free(tmp_ctx);
 141                                                     return NULL;
 142                                             }
 143                                             tmp_acl->aces[tmp_acl->num_aces] = *ace;
 144                                             tmp_acl->aces[tmp_acl->num_aces].flags &= ~SEC_ACE_FLAG_INHERIT_ONLY;
 145                                             tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERITED_ACE;
 146                                             if (dom_sid_equal(&tmp_acl->aces[tmp_acl->num_aces].trustee, co)) {
 147                                                     tmp_acl->aces[tmp_acl->num_aces].trustee = *owner;
 148                                             }
 149                                             if (dom_sid_equal(&tmp_acl->aces[tmp_acl->num_aces].trustee, cg)) {
 150                                                     tmp_acl->aces[tmp_acl->num_aces].trustee = *group;
 151                                             }
 152                                             tmp_acl->aces[tmp_acl->num_aces].flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 153                                             tmp_acl->aces[tmp_acl->num_aces].access_mask =
 154                                                     map_generic_rights_ds(ace->access_mask);
 155                                             tmp_acl->num_aces++;
 156                                 }
 157                         }
 158                 }
 159         }
 160         if (tmp_acl->num_aces == 0) {
 161                 return NULL;
 162         }
 163         if (acl) {
 164                 tmp_acl->revision = acl->revision;
 165         }
 166         return tmp_acl;
 167 }
 168
 169 static struct security_acl *process_user_acl(TALLOC_CTX *mem_ctx,
 170                                              struct security_acl *acl,
 171                                              bool is_container,
 172                                              struct dom_sid *owner,
 173                                              struct dom_sid *group,
 174                                              struct GUID *object_list)
 175 {
 176         uint32_t i;
 177         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 178         struct security_acl *tmp_acl = talloc_zero(tmp_ctx, struct security_acl);
 179         struct security_acl *new_acl;
 180         struct dom_sid *co, *cg;
 181
 182         if (!acl)
 183                 return NULL;
 184
 185         if (!tmp_acl)
 186                 return NULL;
 187
 188         tmp_acl->revision = acl->revision;
 189         DEBUG(6,(__location__ ": acl revision %u\n", acl->revision));
 190
 191         co = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_OWNER);
 192         cg = dom_sid_parse_talloc(tmp_ctx,  SID_CREATOR_GROUP);
 193
 194         for (i=0; i < acl->num_aces; i++){
 195                 struct security_ace *ace = &acl->aces[i];
 196                 if (ace->flags & SEC_ACE_FLAG_INHERITED_ACE)
 197                         continue;
 198                 if (ace->flags & SEC_ACE_FLAG_INHERIT_ONLY &&
 199                     !(ace->flags & SEC_ACE_FLAG_CONTAINER_INHERIT ||
 200                       ace->flags & SEC_ACE_FLAG_OBJECT_INHERIT))
 201                         continue;
 202
 203                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 204                                               tmp_acl->num_aces+1);
 205                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 206                 if (dom_sid_equal(&(tmp_acl->aces[tmp_acl->num_aces].trustee), co)) {
 207                         tmp_acl->aces[tmp_acl->num_aces].trustee = *owner;
 208                         tmp_acl->aces[tmp_acl->num_aces].flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 209                 }
 210                 if (dom_sid_equal(&(tmp_acl->aces[tmp_acl->num_aces].trustee), cg)) {
 211                         tmp_acl->aces[tmp_acl->num_aces].trustee = *group;
 212                         tmp_acl->aces[tmp_acl->num_aces].flags &= ~SEC_ACE_FLAG_CONTAINER_INHERIT;
 213                         }
 214                 tmp_acl->aces[tmp_acl->num_aces].access_mask =
 215                         map_generic_rights_ds(tmp_acl->aces[tmp_acl->num_aces].access_mask);
 216                 tmp_acl->num_aces++;
 217
 218                 if (!dom_sid_equal(&ace->trustee, co) && !dom_sid_equal(&ace->trustee, cg))
 219                         continue;
 220
 221                 tmp_acl->aces = talloc_realloc(tmp_acl, tmp_acl->aces, struct security_ace,
 222                                                tmp_acl->num_aces+1);
 223                 tmp_acl->aces[tmp_acl->num_aces] = *ace;
 224                 tmp_acl->aces[tmp_acl->num_aces].flags |= SEC_ACE_FLAG_INHERIT_ONLY;
 225                 tmp_acl->num_aces++;
 226         }
 227         new_acl = security_acl_dup(mem_ctx,tmp_acl);
 228
 229         if (new_acl)
 230                 new_acl->revision = acl->revision;
 231
 232         talloc_free(tmp_ctx);
 233         return new_acl;
 234 }
 235
 236 static void cr_descr_log_descriptor(struct security_descriptor *sd,
 237                                     const char *message,
 238                                     int level)
 239 {
 240         if (sd) {
 241                 DEBUG(level,("%s: %s\n", message,
 242                              ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_descriptor,
 243                                                      "", sd)));
 244         }
 245         else {
 246                 DEBUG(level,("%s: NULL\n", message));
 247         }
 248 }
 249
 250 static void cr_descr_log_acl(struct security_acl *acl,
 251                                     const char *message,
 252                                     int level)
 253 {
 254         if (acl) {
 255                 DEBUG(level,("%s: %s\n", message,
 256                              ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_acl,
 257                                                      "", acl)));
 258         }
 259         else {
 260                 DEBUG(level,("%s: NULL\n", message));
 261         }
 262 }
 263
 264 static bool compute_acl(struct security_descriptor *parent_sd,
 265                         struct security_descriptor *creator_sd,
 266                         bool is_container,
 267                         uint32_t inherit_flags,
 268                         struct GUID *object_list,
 269                         uint32_t (*generic_map)(uint32_t access_mask),
 270                         struct security_token *token,
 271                         struct security_descriptor *new_sd) /* INOUT argument */
 272 {
 273         struct security_acl *user_dacl, *user_sacl, *inherited_dacl, *inherited_sacl;
 274         int level = 10;
 275
 276         if (!parent_sd || !(inherit_flags & SEC_DACL_AUTO_INHERIT)) {
 277                 inherited_dacl = NULL;
 278         } else if (creator_sd && (creator_sd->type & SEC_DESC_DACL_PROTECTED)) {
 279                 inherited_dacl = NULL;
 280         } else {
 281                 inherited_dacl = calculate_inherited_from_parent(new_sd,
 282                                                                  parent_sd->dacl,
 283                                                                  is_container,
 284                                                                  new_sd->owner_sid,
 285                                                                  new_sd->group_sid,
 286                                                                  object_list);
 287         }
 288
 289
 290         if (!parent_sd || !(inherit_flags & SEC_SACL_AUTO_INHERIT)) {
 291                 inherited_sacl = NULL;
 292         } else if (creator_sd && (creator_sd->type & SEC_DESC_SACL_PROTECTED)) {
 293                 inherited_sacl = NULL;
 294         } else {
 295                 inherited_sacl = calculate_inherited_from_parent(new_sd,
 296                                                                  parent_sd->sacl,
 297                                                                  is_container,
 298                                                                  new_sd->owner_sid,
 299                                                                  new_sd->group_sid,
 300                                                                  object_list);
 301         }
 302
 303         if (!creator_sd || (inherit_flags & SEC_DEFAULT_DESCRIPTOR)) {
 304                 user_dacl = NULL;
 305                 user_sacl = NULL;
 306         } else {
 307                 user_dacl = process_user_acl(new_sd,
 308                                              creator_sd->dacl,
 309                                              is_container,
 310                                              new_sd->owner_sid,
 311                                              new_sd->group_sid,
 312                                              object_list);
 313                 user_sacl = process_user_acl(new_sd,
 314                                              creator_sd->sacl,
 315                                              is_container,
 316                                              new_sd->owner_sid,
 317                                              new_sd->group_sid,
 318                                              object_list);
 319         }
 320         cr_descr_log_descriptor(parent_sd, __location__"parent_sd", level);
 321         cr_descr_log_descriptor(creator_sd,__location__ "creator_sd", level);
 322
 323         new_sd->dacl = security_acl_concatenate(new_sd, user_dacl, inherited_dacl);
 324         if (new_sd->dacl) {
 325                 new_sd->type |= SEC_DESC_DACL_PRESENT;
 326         }
 327         if (inherited_dacl) {
 328                 new_sd->type |= SEC_DESC_DACL_AUTO_INHERITED;
 329         }
 330
 331         new_sd->sacl = security_acl_concatenate(new_sd, user_sacl, inherited_sacl);
 332         if (new_sd->sacl) {
 333                 new_sd->type |= SEC_DESC_SACL_PRESENT;
 334         }
 335         if (inherited_sacl) {
 336                 new_sd->type |= SEC_DESC_SACL_AUTO_INHERITED;
 337         }
 338         /* This is a hack to handle the fact that
 339          * apprantly any AI flag provided by the user is preserved */
 340         if (creator_sd)
 341                 new_sd->type |= creator_sd->type;
 342         cr_descr_log_descriptor(new_sd, __location__"final sd", level);
 343         return true;
 344 }
 345
 346 struct security_descriptor *create_security_descriptor(TALLOC_CTX *mem_ctx,
 347                                                        struct security_descriptor *parent_sd,
 348                                                        struct security_descriptor *creator_sd,
 349                                                        bool is_container,
 350                                                        struct GUID *object_list,
 351                                                        uint32_t inherit_flags,
 352                                                        struct security_token *token,
 353                                                        struct dom_sid *default_owner, /* valid only for DS, NULL for the other RSs */
 354                                                        struct dom_sid *default_group, /* valid only for DS, NULL for the other RSs */
 355                                                        uint32_t (*generic_map)(uint32_t access_mask))
 356 {
 357         struct security_descriptor *new_sd;
 358         struct dom_sid *new_owner = NULL;
 359         struct dom_sid *new_group = NULL;
 360
 361         new_sd = security_descriptor_initialise(mem_ctx);
 362         if (!new_sd) {
 363                 return NULL;
 364         }
 365
 366         if (!creator_sd || !creator_sd->owner_sid) {
 367                 if ((inherit_flags & SEC_OWNER_FROM_PARENT) && parent_sd) {
 368                         new_owner = parent_sd->owner_sid;
 369                 } else if (!default_owner) {
 370                         new_owner = &token->sids[PRIMARY_USER_SID_INDEX];
 371                 } else {
 372                         new_owner = default_owner;
 373                         new_sd->type |= SEC_DESC_OWNER_DEFAULTED;
 374                 }
 375         } else {
 376                 new_owner = creator_sd->owner_sid;
 377         }
 378
 379         if (!creator_sd || !creator_sd->group_sid){
 380                 if ((inherit_flags & SEC_GROUP_FROM_PARENT) && parent_sd) {
 381                         new_group = parent_sd->group_sid;
 382                 } else if (!default_group && token->num_sids > PRIMARY_GROUP_SID_INDEX) {
 383                         new_group = &token->sids[PRIMARY_GROUP_SID_INDEX];
 384                 } else if (!default_group) {
 385                         /* This will happen only for anonymous, which has no other groups */
 386                         new_group = &token->sids[PRIMARY_USER_SID_INDEX];
 387                 } else {
 388                         new_group = default_group;
 389                         new_sd->type |= SEC_DESC_GROUP_DEFAULTED;
 390                 }
 391         } else {
 392                 new_group = creator_sd->group_sid;
 393         }
 394
 395         new_sd->owner_sid = talloc_memdup(new_sd, new_owner, sizeof(struct dom_sid));
 396         new_sd->group_sid = talloc_memdup(new_sd, new_group, sizeof(struct dom_sid));
 397         if (!new_sd->owner_sid || !new_sd->group_sid){
 398                 talloc_free(new_sd);
 399                 return NULL;
 400         }
 401
 402         if (!compute_acl(parent_sd, creator_sd,
 403                          is_container, inherit_flags, object_list,
 404                          generic_map,token,new_sd)){
 405                 talloc_free(new_sd);
 406                 return NULL;
 407         }
 408
 409         return new_sd;
 410 }