source3/modules/vfs_acl_common.c

   1 /*
   2  * Store Windows ACLs in data store - common functions.
   3  * #included into modules/vfs_acl_xattr.c and modules/vfs_acl_tdb.c
   4  *
   5  * Copyright (C) Volker Lendecke, 2008
   6  * Copyright (C) Jeremy Allison, 2009
   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 "smbd/smbd.h"
  23 #include "system/filesys.h"
  24 #include "../libcli/security/security.h"
  25 #include "../librpc/gen_ndr/ndr_security.h"
  26 #include "../lib/util/bitmap.h"
  27
  28 static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
  29                         DATA_BLOB *pblob,
  30                         uint16_t hash_type,
  31                         uint8_t hash[XATTR_SD_HASH_SIZE]);
  32
  33 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  34                         vfs_handle_struct *handle,
  35                         files_struct *fsp,
  36                         const char *name,
  37                         DATA_BLOB *pblob);
  38
  39 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
  40                         files_struct *fsp,
  41                         DATA_BLOB *pblob);
  42
  43 #define HASH_SECURITY_INFO (SECINFO_OWNER | \
  44                                 SECINFO_GROUP | \
  45                                 SECINFO_DACL | \
  46                                 SECINFO_SACL)
  47
  48 /*******************************************************************
  49  Hash a security descriptor.
  50 *******************************************************************/
  51
  52 static NTSTATUS hash_blob_sha256(DATA_BLOB blob,
  53                                  uint8_t *hash)
  54 {
  55         SHA256_CTX tctx;
  56
  57         memset(hash, '\0', XATTR_SD_HASH_SIZE);
  58
  59         samba_SHA256_Init(&tctx);
  60         samba_SHA256_Update(&tctx, blob.data, blob.length);
  61         samba_SHA256_Final(hash, &tctx);
  62
  63         return NT_STATUS_OK;
  64 }
  65
  66 /*******************************************************************
  67  Hash a security descriptor.
  68 *******************************************************************/
  69
  70 static NTSTATUS hash_sd_sha256(struct security_descriptor *psd,
  71                         uint8_t *hash)
  72 {
  73         DATA_BLOB blob;
  74         NTSTATUS status;
  75
  76         memset(hash, '\0', XATTR_SD_HASH_SIZE);
  77         status = create_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash);
  78         if (!NT_STATUS_IS_OK(status)) {
  79                 return status;
  80         }
  81         return hash_blob_sha256(blob, hash);
  82 }
  83
  84 /*******************************************************************
  85  Parse out a struct security_descriptor from a DATA_BLOB.
  86 *******************************************************************/
  87
  88 static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
  89                                TALLOC_CTX *mem_ctx,
  90                                struct security_descriptor **ppdesc,
  91                                uint16_t *p_hash_type,
  92                                uint16_t *p_version,
  93                                uint8_t hash[XATTR_SD_HASH_SIZE],
  94                                uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE])
  95 {
  96         struct xattr_NTACL xacl;
  97         enum ndr_err_code ndr_err;
  98         size_t sd_size;
  99         TALLOC_CTX *frame = talloc_stackframe();
 100
 101         ndr_err = ndr_pull_struct_blob(pblob, frame, &xacl,
 102                         (ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);
 103
 104         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 105                 DEBUG(5, ("parse_acl_blob: ndr_pull_xattr_NTACL failed: %s\n",
 106                         ndr_errstr(ndr_err)));
 107                 TALLOC_FREE(frame);
 108                 return ndr_map_error2ntstatus(ndr_err);
 109         }
 110
 111         *p_version = xacl.version;
 112
 113         switch (xacl.version) {
 114                 case 1:
 115                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 116                                         xacl.info.sd->type | SEC_DESC_SELF_RELATIVE,
 117                                         xacl.info.sd->owner_sid,
 118                                         xacl.info.sd->group_sid,
 119                                         xacl.info.sd->sacl,
 120                                         xacl.info.sd->dacl,
 121                                         &sd_size);
 122                         /* No hash - null out. */
 123                         *p_hash_type = XATTR_SD_HASH_TYPE_NONE;
 124                         memset(hash, '\0', XATTR_SD_HASH_SIZE);
 125                         break;
 126                 case 2:
 127                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 128                                         xacl.info.sd_hs2->sd->type | SEC_DESC_SELF_RELATIVE,
 129                                         xacl.info.sd_hs2->sd->owner_sid,
 130                                         xacl.info.sd_hs2->sd->group_sid,
 131                                         xacl.info.sd_hs2->sd->sacl,
 132                                         xacl.info.sd_hs2->sd->dacl,
 133                                         &sd_size);
 134                         /* No hash - null out. */
 135                         *p_hash_type = XATTR_SD_HASH_TYPE_NONE;
 136                         memset(hash, '\0', XATTR_SD_HASH_SIZE);
 137                         break;
 138                 case 3:
 139                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 140                                         xacl.info.sd_hs3->sd->type | SEC_DESC_SELF_RELATIVE,
 141                                         xacl.info.sd_hs3->sd->owner_sid,
 142                                         xacl.info.sd_hs3->sd->group_sid,
 143                                         xacl.info.sd_hs3->sd->sacl,
 144                                         xacl.info.sd_hs3->sd->dacl,
 145                                         &sd_size);
 146                         *p_hash_type = xacl.info.sd_hs3->hash_type;
 147                         /* Current version 3 (if no sys acl hash available). */
 148                         memcpy(hash, xacl.info.sd_hs3->hash, XATTR_SD_HASH_SIZE);
 149                         break;
 150                 case 4:
 151                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 152                                         xacl.info.sd_hs4->sd->type | SEC_DESC_SELF_RELATIVE,
 153                                         xacl.info.sd_hs4->sd->owner_sid,
 154                                         xacl.info.sd_hs4->sd->group_sid,
 155                                         xacl.info.sd_hs4->sd->sacl,
 156                                         xacl.info.sd_hs4->sd->dacl,
 157                                         &sd_size);
 158                         *p_hash_type = xacl.info.sd_hs4->hash_type;
 159                         /* Current version 4. */
 160                         memcpy(hash, xacl.info.sd_hs4->hash, XATTR_SD_HASH_SIZE);
 161                         memcpy(sys_acl_hash, xacl.info.sd_hs4->sys_acl_hash, XATTR_SD_HASH_SIZE);
 162                         break;
 163                 default:
 164                         TALLOC_FREE(frame);
 165                         return NT_STATUS_REVISION_MISMATCH;
 166         }
 167
 168         TALLOC_FREE(frame);
 169
 170         return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
 171 }
 172
 173 /*******************************************************************
 174  Create a DATA_BLOB from a hash of the security descriptor storead at
 175  the system layer and the NT ACL we wish to preserve
 176 *******************************************************************/
 177
 178 static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
 179                         DATA_BLOB *pblob,
 180                         uint16_t hash_type,
 181                         uint8_t hash[XATTR_SD_HASH_SIZE])
 182 {
 183         struct xattr_NTACL xacl;
 184         struct security_descriptor_hash_v3 sd_hs3;
 185         enum ndr_err_code ndr_err;
 186         TALLOC_CTX *ctx = talloc_tos();
 187
 188         ZERO_STRUCT(xacl);
 189         ZERO_STRUCT(sd_hs3);
 190
 191         xacl.version = 3;
 192         xacl.info.sd_hs3 = &sd_hs3;
 193         xacl.info.sd_hs3->sd = discard_const_p(struct security_descriptor, psd);
 194         xacl.info.sd_hs3->hash_type = hash_type;
 195         memcpy(&xacl.info.sd_hs3->hash[0], hash, XATTR_SD_HASH_SIZE);
 196
 197         ndr_err = ndr_push_struct_blob(
 198                         pblob, ctx, &xacl,
 199                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 200
 201         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 202                 DEBUG(5, ("create_acl_blob: ndr_push_xattr_NTACL failed: %s\n",
 203                         ndr_errstr(ndr_err)));
 204                 return ndr_map_error2ntstatus(ndr_err);
 205         }
 206
 207         return NT_STATUS_OK;
 208 }
 209
 210 /*******************************************************************
 211  Create a DATA_BLOB from a hash of the security descriptors
 212  (system and NT) stored at the system layer and the NT ACL we wish
 213  to preserve.
 214 *******************************************************************/
 215
 216 static NTSTATUS create_sys_acl_blob(const struct security_descriptor *psd,
 217                                     DATA_BLOB *pblob,
 218                                     uint16_t hash_type,
 219                                     uint8_t hash[XATTR_SD_HASH_SIZE],
 220                                     const char *description,
 221                                     uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE])
 222 {
 223         struct xattr_NTACL xacl;
 224         struct security_descriptor_hash_v4 sd_hs4;
 225         enum ndr_err_code ndr_err;
 226         TALLOC_CTX *ctx = talloc_tos();
 227         NTTIME nttime_now;
 228         struct timeval now = timeval_current();
 229         nttime_now = timeval_to_nttime(&now);
 230
 231         ZERO_STRUCT(xacl);
 232         ZERO_STRUCT(sd_hs4);
 233
 234         xacl.version = 4;
 235         xacl.info.sd_hs4 = &sd_hs4;
 236         xacl.info.sd_hs4->sd = discard_const_p(struct security_descriptor, psd);
 237         xacl.info.sd_hs4->hash_type = hash_type;
 238         memcpy(&xacl.info.sd_hs4->hash[0], hash, XATTR_SD_HASH_SIZE);
 239         xacl.info.sd_hs4->description = description;
 240         xacl.info.sd_hs4->time = nttime_now;
 241         memcpy(&xacl.info.sd_hs4->sys_acl_hash[0], sys_acl_hash, XATTR_SD_HASH_SIZE);
 242
 243         ndr_err = ndr_push_struct_blob(
 244                         pblob, ctx, &xacl,
 245                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 246
 247         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 248                 DEBUG(5, ("create_acl_blob: ndr_push_xattr_NTACL failed: %s\n",
 249                         ndr_errstr(ndr_err)));
 250                 return ndr_map_error2ntstatus(ndr_err);
 251         }
 252
 253         return NT_STATUS_OK;
 254 }
 255
 256 /*******************************************************************
 257  Add in 3 inheritable components for a non-inheritable directory ACL.
 258  CREATOR_OWNER/CREATOR_GROUP/WORLD.
 259 *******************************************************************/
 260
 261 static NTSTATUS add_directory_inheritable_components(vfs_handle_struct *handle,
 262                                 const char *name,
 263                                 SMB_STRUCT_STAT *psbuf,
 264                                 struct security_descriptor *psd)
 265 {
 266         struct connection_struct *conn = handle->conn;
 267         int num_aces = (psd->dacl ? psd->dacl->num_aces : 0);
 268         struct smb_filename smb_fname;
 269         enum security_ace_type acltype;
 270         uint32_t access_mask;
 271         mode_t dir_mode;
 272         mode_t file_mode;
 273         mode_t mode;
 274         struct security_ace *new_ace_list;
 275
 276         if (psd->dacl) {
 277                 new_ace_list = talloc_zero_array(psd->dacl,
 278                                                  struct security_ace,
 279                                                  num_aces + 3);
 280         } else {
 281                 /*
 282                  * make_sec_acl() at the bottom of this function
 283                  * dupliates new_ace_list
 284                  */
 285                 new_ace_list = talloc_zero_array(talloc_tos(),
 286                                                  struct security_ace,
 287                                                  num_aces + 3);
 288         }
 289
 290         if (new_ace_list == NULL) {
 291                 return NT_STATUS_NO_MEMORY;
 292         }
 293
 294         /* Fake a quick smb_filename. */
 295         ZERO_STRUCT(smb_fname);
 296         smb_fname.st = *psbuf;
 297         smb_fname.base_name = discard_const_p(char, name);
 298
 299         dir_mode = unix_mode(conn,
 300                         FILE_ATTRIBUTE_DIRECTORY, &smb_fname, NULL);
 301         file_mode = unix_mode(conn,
 302                         FILE_ATTRIBUTE_ARCHIVE, &smb_fname, NULL);
 303
 304         mode = dir_mode | file_mode;
 305
 306         DEBUG(10, ("add_directory_inheritable_components: directory %s, "
 307                 "mode = 0%o\n",
 308                 name,
 309                 (unsigned int)mode ));
 310
 311         if (num_aces) {
 312                 memcpy(new_ace_list, psd->dacl->aces,
 313                         num_aces * sizeof(struct security_ace));
 314         }
 315         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 316                                 mode & 0700, false);
 317
 318         init_sec_ace(&new_ace_list[num_aces],
 319                         &global_sid_Creator_Owner,
 320                         acltype,
 321                         access_mask,
 322                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 323                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 324                                 SEC_ACE_FLAG_INHERIT_ONLY);
 325         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 326                                 (mode << 3) & 0700, false);
 327         init_sec_ace(&new_ace_list[num_aces+1],
 328                         &global_sid_Creator_Group,
 329                         acltype,
 330                         access_mask,
 331                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 332                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 333                                 SEC_ACE_FLAG_INHERIT_ONLY);
 334         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 335                                 (mode << 6) & 0700, false);
 336         init_sec_ace(&new_ace_list[num_aces+2],
 337                         &global_sid_World,
 338                         acltype,
 339                         access_mask,
 340                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 341                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 342                                 SEC_ACE_FLAG_INHERIT_ONLY);
 343         if (psd->dacl) {
 344                 psd->dacl->aces = new_ace_list;
 345                 psd->dacl->num_aces += 3;
 346         } else {
 347                 psd->dacl = make_sec_acl(psd,
 348                                 NT4_ACL_REVISION,
 349                                 3,
 350                                 new_ace_list);
 351                 if (psd->dacl == NULL) {
 352                         return NT_STATUS_NO_MEMORY;
 353                 }
 354         }
 355         return NT_STATUS_OK;
 356 }
 357
 358 /*******************************************************************
 359  Pull a DATA_BLOB from an xattr given a pathname.
 360  If the hash doesn't match, or doesn't exist - return the underlying
 361  filesystem sd.
 362 *******************************************************************/
 363
 364 static NTSTATUS get_nt_acl_internal(vfs_handle_struct *handle,
 365                                 files_struct *fsp,
 366                                 const char *name,
 367                                 uint32_t security_info,
 368                                 TALLOC_CTX *mem_ctx,
 369                                     struct security_descriptor **ppdesc)
 370 {
 371         DATA_BLOB blob = data_blob_null;
 372         NTSTATUS status;
 373         uint16_t hash_type = XATTR_SD_HASH_TYPE_NONE;
 374         uint16_t xattr_version = 0;
 375         uint8_t hash[XATTR_SD_HASH_SIZE];
 376         uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE];
 377         uint8_t hash_tmp[XATTR_SD_HASH_SIZE];
 378         uint8_t sys_acl_hash_tmp[XATTR_SD_HASH_SIZE];
 379         struct security_descriptor *psd = NULL;
 380         struct security_descriptor *pdesc_next = NULL;
 381         bool ignore_file_system_acl = lp_parm_bool(SNUM(handle->conn),
 382                                                 ACL_MODULE_NAME,
 383                                                 "ignore system acls",
 384                                                 false);
 385         TALLOC_CTX *frame = talloc_stackframe();
 386
 387         if (fsp && name == NULL) {
 388                 name = fsp->fsp_name->base_name;
 389         }
 390
 391         DEBUG(10, ("get_nt_acl_internal: name=%s\n", name));
 392
 393         /* Get the full underlying sd for the hash
 394            or to return as backup. */
 395         if (fsp) {
 396                 status = SMB_VFS_NEXT_FGET_NT_ACL(handle,
 397                                                   fsp,
 398                                                   HASH_SECURITY_INFO,
 399                                                   mem_ctx,
 400                                                   &pdesc_next);
 401         } else {
 402                 status = SMB_VFS_NEXT_GET_NT_ACL(handle,
 403                                                  name,
 404                                                  HASH_SECURITY_INFO,
 405                                                  mem_ctx,
 406                                                  &pdesc_next);
 407         }
 408
 409         if (!NT_STATUS_IS_OK(status)) {
 410                 DEBUG(10, ("get_nt_acl_internal: get_next_acl for file %s "
 411                         "returned %s\n",
 412                         name,
 413                         nt_errstr(status)));
 414                 TALLOC_FREE(frame);
 415                 return status;
 416         }
 417
 418         /* Ensure we don't leak psd_next if we don't choose it.
 419          *
 420          * We don't allocate it onto frame as it is preferred not to
 421          * steal from a talloc pool.
 422          */
 423         talloc_steal(frame, pdesc_next);
 424
 425         status = get_acl_blob(frame, handle, fsp, name, &blob);
 426         if (!NT_STATUS_IS_OK(status)) {
 427                 DEBUG(10, ("get_nt_acl_internal: get_acl_blob returned %s\n",
 428                         nt_errstr(status)));
 429                 psd = pdesc_next;
 430                 goto out;
 431         }
 432
 433         status = parse_acl_blob(&blob, mem_ctx, &psd,
 434                                 &hash_type, &xattr_version, &hash[0], &sys_acl_hash[0]);
 435         if (!NT_STATUS_IS_OK(status)) {
 436                 DEBUG(10, ("parse_acl_blob returned %s\n",
 437                                 nt_errstr(status)));
 438                 psd = pdesc_next;
 439                 goto out;
 440         }
 441
 442         /* Ensure we don't leak psd if we don't choose it.
 443          *
 444          * We don't allocate it onto frame as it is preferred not to
 445          * steal from a talloc pool.
 446          */
 447         talloc_steal(frame, psd);
 448
 449         /* determine which type of xattr we got */
 450         switch (xattr_version) {
 451         case 1:
 452         case 2:
 453                 /* These xattr types are unilatteral, they do not
 454                  * require confirmation of the hash.  In particular,
 455                  * the NTVFS file server uses version 1, but
 456                  * 'samba-tool ntacl' can set these as well */
 457                 goto out;
 458         case 3:
 459         case 4:
 460                 if (ignore_file_system_acl) {
 461                         goto out;
 462                 }
 463
 464                 break;
 465         default:
 466                 DEBUG(10, ("get_nt_acl_internal: ACL blob revision "
 467                            "mismatch (%u) for file %s\n",
 468                            (unsigned int)hash_type,
 469                            name));
 470                 TALLOC_FREE(psd);
 471                 psd = pdesc_next;
 472                 goto out;
 473         }
 474
 475         /* determine which type of xattr we got */
 476         if (hash_type != XATTR_SD_HASH_TYPE_SHA256) {
 477                 DEBUG(10, ("get_nt_acl_internal: ACL blob hash type "
 478                            "(%u) unexpected for file %s\n",
 479                            (unsigned int)hash_type,
 480                            name));
 481                 TALLOC_FREE(psd);
 482                 psd = pdesc_next;
 483                 goto out;
 484         }
 485
 486         /* determine which type of xattr we got */
 487         switch (xattr_version) {
 488         case 4:
 489         {
 490                 int ret;
 491                 char *sys_acl_blob_description;
 492                 DATA_BLOB sys_acl_blob;
 493                 if (fsp) {
 494                         /* Get the full underlying sd, then hash. */
 495                         ret = SMB_VFS_NEXT_SYS_ACL_BLOB_GET_FD(handle,
 496                                                                fsp,
 497                                                                frame,
 498                                                                &sys_acl_blob_description,
 499                                                                &sys_acl_blob);
 500                 } else {
 501                         /* Get the full underlying sd, then hash. */
 502                         ret = SMB_VFS_NEXT_SYS_ACL_BLOB_GET_FILE(handle,
 503                                                                  name,
 504                                                                  frame,
 505                                                                  &sys_acl_blob_description,
 506                                                                  &sys_acl_blob);
 507                 }
 508
 509                 /* If we fail to get the ACL blob (for some reason) then this
 510                  * is not fatal, we just work based on the NT ACL only */
 511                 if (ret == 0) {
 512                         status = hash_blob_sha256(sys_acl_blob, sys_acl_hash_tmp);
 513                         if (!NT_STATUS_IS_OK(status)) {
 514                                 TALLOC_FREE(frame);
 515                                 return status;
 516                         }
 517
 518                         if (memcmp(&sys_acl_hash[0], &sys_acl_hash_tmp[0],
 519                                    XATTR_SD_HASH_SIZE) == 0) {
 520                                 /* Hash matches, return blob sd. */
 521                                 DEBUG(10, ("get_nt_acl_internal: blob hash "
 522                                            "matches for file %s\n",
 523                                            name ));
 524                                 goto out;
 525                         }
 526                 }
 527
 528                 /* Otherwise, fall though and see if the NT ACL hash matches */
 529         }
 530         case 3:
 531                 status = hash_sd_sha256(pdesc_next, hash_tmp);
 532                 if (!NT_STATUS_IS_OK(status)) {
 533                         TALLOC_FREE(psd);
 534                         psd = pdesc_next;
 535                         goto out;
 536                 }
 537
 538                 if (memcmp(&hash[0], &hash_tmp[0], XATTR_SD_HASH_SIZE) == 0) {
 539                         /* Hash matches, return blob sd. */
 540                         DEBUG(10, ("get_nt_acl_internal: blob hash "
 541                                    "matches for file %s\n",
 542                                    name ));
 543                         goto out;
 544                 }
 545
 546                 /* Hash doesn't match, return underlying sd. */
 547                 DEBUG(10, ("get_nt_acl_internal: blob hash "
 548                            "does not match for file %s - returning "
 549                            "file system SD mapping.\n",
 550                            name ));
 551
 552                 if (DEBUGLEVEL >= 10) {
 553                         DEBUG(10,("get_nt_acl_internal: acl for blob hash for %s is:\n",
 554                                   name ));
 555                         NDR_PRINT_DEBUG(security_descriptor, pdesc_next);
 556                 }
 557
 558                 TALLOC_FREE(psd);
 559                 psd = pdesc_next;
 560         }
 561   out:
 562
 563         if (psd != pdesc_next) {
 564                 /* We're returning the blob, throw
 565                  * away the filesystem SD. */
 566                 TALLOC_FREE(pdesc_next);
 567         } else {
 568                 SMB_STRUCT_STAT sbuf;
 569                 SMB_STRUCT_STAT *psbuf = &sbuf;
 570                 bool is_directory = false;
 571                 /*
 572                  * We're returning the underlying ACL from the
 573                  * filesystem. If it's a directory, and has no
 574                  * inheritable ACE entries we have to fake them.
 575                  */
 576                 if (fsp) {
 577                         status = vfs_stat_fsp(fsp);
 578                         if (!NT_STATUS_IS_OK(status)) {
 579                                 TALLOC_FREE(frame);
 580                                 return status;
 581                         }
 582                         psbuf = &fsp->fsp_name->st;
 583                 } else {
 584                         int ret = vfs_stat_smb_fname(handle->conn,
 585                                                 name,
 586                                                 &sbuf);
 587                         if (ret == -1) {
 588                                 TALLOC_FREE(frame);
 589                                 return map_nt_error_from_unix(errno);
 590                         }
 591                 }
 592                 is_directory = S_ISDIR(psbuf->st_ex_mode);
 593
 594                 if (ignore_file_system_acl) {
 595                         TALLOC_FREE(pdesc_next);
 596                         status = make_default_filesystem_acl(mem_ctx,
 597                                                 name,
 598                                                 psbuf,
 599                                                 &psd);
 600                         if (!NT_STATUS_IS_OK(status)) {
 601                                 TALLOC_FREE(frame);
 602                                 return status;
 603                         }
 604                 } else {
 605                         if (is_directory &&
 606                                 !sd_has_inheritable_components(psd,
 607                                                         true)) {
 608                                 status = add_directory_inheritable_components(
 609                                                         handle,
 610                                                         name,
 611                                                         psbuf,
 612                                                         psd);
 613                                 if (!NT_STATUS_IS_OK(status)) {
 614                                         TALLOC_FREE(frame);
 615                                         return status;
 616                                 }
 617                         }
 618                         /* The underlying POSIX module always sets
 619                            the ~SEC_DESC_DACL_PROTECTED bit, as ACLs
 620                            can't be inherited in this way under POSIX.
 621                            Remove it for Windows-style ACLs. */
 622                         psd->type &= ~SEC_DESC_DACL_PROTECTED;
 623                 }
 624         }
 625
 626         if (!(security_info & SECINFO_OWNER)) {
 627                 psd->owner_sid = NULL;
 628         }
 629         if (!(security_info & SECINFO_GROUP)) {
 630                 psd->group_sid = NULL;
 631         }
 632         if (!(security_info & SECINFO_DACL)) {
 633                 psd->type &= ~SEC_DESC_DACL_PRESENT;
 634                 psd->dacl = NULL;
 635         }
 636         if (!(security_info & SECINFO_SACL)) {
 637                 psd->type &= ~SEC_DESC_SACL_PRESENT;
 638                 psd->sacl = NULL;
 639         }
 640
 641         TALLOC_FREE(blob.data);
 642
 643         if (DEBUGLEVEL >= 10) {
 644                 DEBUG(10,("get_nt_acl_internal: returning acl for %s is:\n",
 645                         name ));
 646                 NDR_PRINT_DEBUG(security_descriptor, psd);
 647         }
 648
 649         /* The VFS API is that the ACL is expected to be on mem_ctx */
 650         *ppdesc = talloc_move(mem_ctx, &psd);
 651
 652         TALLOC_FREE(frame);
 653         return NT_STATUS_OK;
 654 }
 655
 656 /*********************************************************************
 657  Fetch a security descriptor given an fsp.
 658 *********************************************************************/
 659
 660 static NTSTATUS fget_nt_acl_common(vfs_handle_struct *handle,
 661                                    files_struct *fsp,
 662                                    uint32_t security_info,
 663                                    TALLOC_CTX *mem_ctx,
 664                                    struct security_descriptor **ppdesc)
 665 {
 666         return get_nt_acl_internal(handle, fsp,
 667                                    NULL, security_info, mem_ctx, ppdesc);
 668 }
 669
 670 /*********************************************************************
 671  Fetch a security descriptor given a pathname.
 672 *********************************************************************/
 673
 674 static NTSTATUS get_nt_acl_common(vfs_handle_struct *handle,
 675                                   const char *name,
 676                                   uint32_t security_info,
 677                                   TALLOC_CTX *mem_ctx,
 678                                   struct security_descriptor **ppdesc)
 679 {
 680         return get_nt_acl_internal(handle, NULL,
 681                                    name, security_info, mem_ctx, ppdesc);
 682 }
 683
 684 /*********************************************************************
 685  Store a security descriptor given an fsp.
 686 *********************************************************************/
 687
 688 static NTSTATUS fset_nt_acl_common(vfs_handle_struct *handle, files_struct *fsp,
 689         uint32_t security_info_sent, const struct security_descriptor *orig_psd)
 690 {
 691         NTSTATUS status;
 692         int ret;
 693         DATA_BLOB blob, sys_acl_blob;
 694         struct security_descriptor *pdesc_next = NULL;
 695         struct security_descriptor *psd = NULL;
 696         uint8_t hash[XATTR_SD_HASH_SIZE];
 697         uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE];
 698         bool chown_needed = false;
 699         char *sys_acl_description;
 700         TALLOC_CTX *frame = talloc_stackframe();
 701
 702         if (DEBUGLEVEL >= 10) {
 703                 DEBUG(10,("fset_nt_acl_xattr: incoming sd for file %s\n",
 704                           fsp_str_dbg(fsp)));
 705                 NDR_PRINT_DEBUG(security_descriptor,
 706                         discard_const_p(struct security_descriptor, orig_psd));
 707         }
 708
 709         status = get_nt_acl_internal(handle, fsp,
 710                         NULL,
 711                         SECINFO_OWNER|SECINFO_GROUP|SECINFO_DACL|SECINFO_SACL,
 712                                      frame,
 713                         &psd);
 714
 715         if (!NT_STATUS_IS_OK(status)) {
 716                 TALLOC_FREE(frame);
 717                 return status;
 718         }
 719
 720         psd->revision = orig_psd->revision;
 721         /* All our SD's are self relative. */
 722         psd->type = orig_psd->type | SEC_DESC_SELF_RELATIVE;
 723
 724         if ((security_info_sent & SECINFO_OWNER) && (orig_psd->owner_sid != NULL)) {
 725                 if (!dom_sid_equal(orig_psd->owner_sid, psd->owner_sid)) {
 726                         /* We're changing the owner. */
 727                         chown_needed = true;
 728                 }
 729                 psd->owner_sid = orig_psd->owner_sid;
 730         }
 731         if ((security_info_sent & SECINFO_GROUP) && (orig_psd->group_sid != NULL)) {
 732                 if (!dom_sid_equal(orig_psd->group_sid, psd->group_sid)) {
 733                         /* We're changing the group. */
 734                         chown_needed = true;
 735                 }
 736                 psd->group_sid = orig_psd->group_sid;
 737         }
 738         if (security_info_sent & SECINFO_DACL) {
 739                 psd->dacl = orig_psd->dacl;
 740                 psd->type |= SEC_DESC_DACL_PRESENT;
 741         }
 742         if (security_info_sent & SECINFO_SACL) {
 743                 psd->sacl = orig_psd->sacl;
 744                 psd->type |= SEC_DESC_SACL_PRESENT;
 745         }
 746
 747         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
 748         if (!NT_STATUS_IS_OK(status)) {
 749                 if (!NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 750                         TALLOC_FREE(frame);
 751                         return status;
 752                 }
 753                 /* We got access denied here. If we're already root,
 754                    or we didn't need to do a chown, or the fsp isn't
 755                    open with WRITE_OWNER access, just return. */
 756                 if (get_current_uid(handle->conn) == 0 ||
 757                                 chown_needed == false ||
 758                                 !(fsp->access_mask & SEC_STD_WRITE_OWNER)) {
 759                         TALLOC_FREE(frame);
 760                         return NT_STATUS_ACCESS_DENIED;
 761                 }
 762
 763                 DEBUG(10,("fset_nt_acl_common: overriding chown on file %s "
 764                         "for sid %s\n",
 765                         fsp_str_dbg(fsp),
 766                         sid_string_tos(psd->owner_sid)
 767                         ));
 768
 769                 /* Ok, we failed to chown and we have
 770                    SEC_STD_WRITE_OWNER access - override. */
 771                 become_root();
 772                 status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp,
 773                                 security_info_sent, psd);
 774                 unbecome_root();
 775                 if (!NT_STATUS_IS_OK(status)) {
 776                         TALLOC_FREE(frame);
 777                         return status;
 778                 }
 779         }
 780
 781         /* Get the full underlying sd, then hash. */
 782         status = SMB_VFS_NEXT_FGET_NT_ACL(handle,
 783                                           fsp,
 784                                           HASH_SECURITY_INFO,
 785                                           frame,
 786                                           &pdesc_next);
 787
 788         if (!NT_STATUS_IS_OK(status)) {
 789                 TALLOC_FREE(frame);
 790                 return status;
 791         }
 792
 793         status = hash_sd_sha256(pdesc_next, hash);
 794         if (!NT_STATUS_IS_OK(status)) {
 795                 TALLOC_FREE(frame);
 796                 return status;
 797         }
 798
 799         /* Get the full underlying sd, then hash. */
 800         ret = SMB_VFS_NEXT_SYS_ACL_BLOB_GET_FD(handle,
 801                                                fsp,
 802                                                frame,
 803                                                &sys_acl_description,
 804                                                &sys_acl_blob);
 805
 806         /* If we fail to get the ACL blob (for some reason) then this
 807          * is not fatal, we just work based on the NT ACL only */
 808         if (ret != 0) {
 809                 if (DEBUGLEVEL >= 10) {
 810                         DEBUG(10,("fset_nt_acl_xattr: storing xattr sd for file %s\n",
 811                                   fsp_str_dbg(fsp)));
 812                         NDR_PRINT_DEBUG(security_descriptor,
 813                                         discard_const_p(struct security_descriptor, psd));
 814
 815                         DEBUG(10,("fset_nt_acl_xattr: storing has in xattr sd based on \n"));
 816                         NDR_PRINT_DEBUG(security_descriptor,
 817                                         discard_const_p(struct security_descriptor, pdesc_next));
 818                 }
 819                 status = create_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash);
 820                 if (!NT_STATUS_IS_OK(status)) {
 821                         DEBUG(10, ("fset_nt_acl_xattr: create_acl_blob failed\n"));
 822                         TALLOC_FREE(frame);
 823                         return status;
 824                 }
 825
 826                 status = store_acl_blob_fsp(handle, fsp, &blob);
 827
 828                 TALLOC_FREE(frame);
 829                 return status;
 830         }
 831
 832         status = hash_blob_sha256(sys_acl_blob, sys_acl_hash);
 833         if (!NT_STATUS_IS_OK(status)) {
 834                 TALLOC_FREE(frame);
 835                 return status;
 836         }
 837
 838         if (DEBUGLEVEL >= 10) {
 839                 DEBUG(10,("fset_nt_acl_xattr: storing xattr sd for file %s based on system ACL\n",
 840                           fsp_str_dbg(fsp)));
 841                 NDR_PRINT_DEBUG(security_descriptor,
 842                                 discard_const_p(struct security_descriptor, psd));
 843
 844                 DEBUG(10,("fset_nt_acl_xattr: storing hash in xattr sd based on system ACL and:\n"));
 845                 NDR_PRINT_DEBUG(security_descriptor,
 846                                 discard_const_p(struct security_descriptor, pdesc_next));
 847         }
 848
 849         /* We store hashes of both the sys ACL blob and the NT
 850          * security desciptor mapped from that ACL so as to improve
 851          * our chances against some inadvertant change breaking the
 852          * hash used */
 853         status = create_sys_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash,
 854                                      sys_acl_description, sys_acl_hash);
 855         if (!NT_STATUS_IS_OK(status)) {
 856                 DEBUG(10, ("fset_nt_acl_xattr: create_sys_acl_blob failed\n"));
 857                 TALLOC_FREE(frame);
 858                 return status;
 859         }
 860
 861         status = store_acl_blob_fsp(handle, fsp, &blob);
 862
 863         TALLOC_FREE(frame);
 864         return status;
 865 }
 866
 867 static int acl_common_remove_object(vfs_handle_struct *handle,
 868                                         const char *path,
 869                                         bool is_directory)
 870 {
 871         connection_struct *conn = handle->conn;
 872         struct file_id id;
 873         files_struct *fsp = NULL;
 874         int ret = 0;
 875         char *parent_dir = NULL;
 876         const char *final_component = NULL;
 877         struct smb_filename local_fname;
 878         int saved_errno = 0;
 879         char *saved_dir = NULL;
 880
 881         saved_dir = vfs_GetWd(talloc_tos(),conn);
 882         if (!saved_dir) {
 883                 saved_errno = errno;
 884                 goto out;
 885         }
 886
 887         if (!parent_dirname(talloc_tos(), path,
 888                         &parent_dir, &final_component)) {
 889                 saved_errno = ENOMEM;
 890                 goto out;
 891         }
 892
 893         DEBUG(10,("acl_common_remove_object: removing %s %s/%s\n",
 894                 is_directory ? "directory" : "file",
 895                 parent_dir, final_component ));
 896
 897         /* cd into the parent dir to pin it. */
 898         ret = vfs_ChDir(conn, parent_dir);
 899         if (ret == -1) {
 900                 saved_errno = errno;
 901                 goto out;
 902         }
 903
 904         ZERO_STRUCT(local_fname);
 905         local_fname.base_name = discard_const_p(char, final_component);
 906
 907         /* Must use lstat here. */
 908         ret = SMB_VFS_LSTAT(conn, &local_fname);
 909         if (ret == -1) {
 910                 saved_errno = errno;
 911                 goto out;
 912         }
 913
 914         /* Ensure we have this file open with DELETE access. */
 915         id = vfs_file_id_from_sbuf(conn, &local_fname.st);
 916         for (fsp = file_find_di_first(conn->sconn, id); fsp;
 917                      fsp = file_find_di_next(fsp)) {
 918                 if (fsp->access_mask & DELETE_ACCESS &&
 919                                 fsp->delete_on_close) {
 920                         /* We did open this for delete,
 921                          * allow the delete as root.
 922                          */
 923                         break;
 924                 }
 925         }
 926
 927         if (!fsp) {
 928                 DEBUG(10,("acl_common_remove_object: %s %s/%s "
 929                         "not an open file\n",
 930                         is_directory ? "directory" : "file",
 931                         parent_dir, final_component ));
 932                 saved_errno = EACCES;
 933                 goto out;
 934         }
 935
 936         become_root();
 937         if (is_directory) {
 938                 ret = SMB_VFS_NEXT_RMDIR(handle, final_component);
 939         } else {
 940                 ret = SMB_VFS_NEXT_UNLINK(handle, &local_fname);
 941         }
 942         unbecome_root();
 943
 944         if (ret == -1) {
 945                 saved_errno = errno;
 946         }
 947
 948   out:
 949
 950         TALLOC_FREE(parent_dir);
 951
 952         if (saved_dir) {
 953                 vfs_ChDir(conn, saved_dir);
 954         }
 955         if (saved_errno) {
 956                 errno = saved_errno;
 957         }
 958         return ret;
 959 }
 960
 961 static int rmdir_acl_common(struct vfs_handle_struct *handle,
 962                                 const char *path)
 963 {
 964         int ret;
 965
 966         /* Try the normal rmdir first. */
 967         ret = SMB_VFS_NEXT_RMDIR(handle, path);
 968         if (ret == 0) {
 969                 return 0;
 970         }
 971         if (errno == EACCES || errno == EPERM) {
 972                 /* Failed due to access denied,
 973                    see if we need to root override. */
 974                 return acl_common_remove_object(handle,
 975                                                 path,
 976                                                 true);
 977         }
 978
 979         DEBUG(10,("rmdir_acl_common: unlink of %s failed %s\n",
 980                 path,
 981                 strerror(errno) ));
 982         return -1;
 983 }
 984
 985 static int unlink_acl_common(struct vfs_handle_struct *handle,
 986                         const struct smb_filename *smb_fname)
 987 {
 988         int ret;
 989
 990         /* Try the normal unlink first. */
 991         ret = SMB_VFS_NEXT_UNLINK(handle, smb_fname);
 992         if (ret == 0) {
 993                 return 0;
 994         }
 995         if (errno == EACCES || errno == EPERM) {
 996                 /* Failed due to access denied,
 997                    see if we need to root override. */
 998
 999                 /* Don't do anything fancy for streams. */
1000                 if (smb_fname->stream_name) {
1001                         return -1;
1002                 }
1003                 return acl_common_remove_object(handle,
1004                                         smb_fname->base_name,
1005                                         false);
1006         }
1007
1008         DEBUG(10,("unlink_acl_common: unlink of %s failed %s\n",
1009                 smb_fname->base_name,
1010                 strerror(errno) ));
1011         return -1;
1012 }
1013
1014 static int chmod_acl_module_common(struct vfs_handle_struct *handle,
1015                         const char *path, mode_t mode)
1016 {
1017         if (lp_posix_pathnames()) {
1018                 /* Only allow this on POSIX pathnames. */
1019                 return SMB_VFS_NEXT_CHMOD(handle, path, mode);
1020         }
1021         return 0;
1022 }
1023
1024 static int fchmod_acl_module_common(struct vfs_handle_struct *handle,
1025                         struct files_struct *fsp, mode_t mode)
1026 {
1027         if (fsp->posix_open) {
1028                 /* Only allow this on POSIX opens. */
1029                 return SMB_VFS_NEXT_FCHMOD(handle, fsp, mode);
1030         }
1031         return 0;
1032 }
1033
1034 static int chmod_acl_acl_module_common(struct vfs_handle_struct *handle,
1035                         const char *name, mode_t mode)
1036 {
1037         if (lp_posix_pathnames()) {
1038                 /* Only allow this on POSIX pathnames. */
1039                 return SMB_VFS_NEXT_CHMOD_ACL(handle, name, mode);
1040         }
1041         return 0;
1042 }
1043
1044 static int fchmod_acl_acl_module_common(struct vfs_handle_struct *handle,
1045                         struct files_struct *fsp, mode_t mode)
1046 {
1047         if (fsp->posix_open) {
1048                 /* Only allow this on POSIX opens. */
1049                 return SMB_VFS_NEXT_FCHMOD_ACL(handle, fsp, mode);
1050         }
1051         return 0;
1052 }