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  * Copyright (C) Ralph Böhme, 2016
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 3 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23 #include "includes.h"
  24 #include "vfs_acl_common.h"
  25 #include "smbd/smbd.h"
  26 #include "system/filesys.h"
  27 #include "librpc/gen_ndr/ndr_xattr.h"
  28 #include "../libcli/security/security.h"
  29 #include "../librpc/gen_ndr/ndr_security.h"
  30 #include "../lib/util/bitmap.h"
  31 #include "passdb/lookup_sid.h"
  32
  33 #include <gnutls/gnutls.h>
  34 #include <gnutls/crypto.h>
  35
  36 static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
  37                         DATA_BLOB *pblob,
  38                         uint16_t hash_type,
  39                         uint8_t hash[XATTR_SD_HASH_SIZE]);
  40
  41 #define HASH_SECURITY_INFO (SECINFO_OWNER | \
  42                                 SECINFO_GROUP | \
  43                                 SECINFO_DACL | \
  44                                 SECINFO_SACL)
  45
  46 bool init_acl_common_config(vfs_handle_struct *handle,
  47                             const char *module_name)
  48 {
  49         struct acl_common_config *config = NULL;
  50         const struct enum_list *default_acl_style_list = NULL;
  51
  52         default_acl_style_list = get_default_acl_style_list();
  53
  54         config = talloc_zero(handle->conn, struct acl_common_config);
  55         if (config == NULL) {
  56                 DBG_ERR("talloc_zero() failed\n");
  57                 errno = ENOMEM;
  58                 return false;
  59         }
  60
  61         config->ignore_system_acls = lp_parm_bool(SNUM(handle->conn),
  62                                                   module_name,
  63                                                   "ignore system acls",
  64                                                   false);
  65         config->default_acl_style = lp_parm_enum(SNUM(handle->conn),
  66                                                  module_name,
  67                                                  "default acl style",
  68                                                  default_acl_style_list,
  69                                                  DEFAULT_ACL_POSIX);
  70
  71         SMB_VFS_HANDLE_SET_DATA(handle, config, NULL,
  72                                 struct acl_common_config,
  73                                 return false);
  74
  75         return true;
  76 }
  77
  78
  79 /*******************************************************************
  80  Hash a security descriptor.
  81 *******************************************************************/
  82
  83 static NTSTATUS hash_blob_sha256(DATA_BLOB blob,
  84                                  uint8_t *hash)
  85 {
  86         int rc;
  87
  88         ZERO_ARRAY_LEN(hash, XATTR_SD_HASH_SIZE);
  89
  90         rc = gnutls_hash_fast(GNUTLS_DIG_SHA256,
  91                               blob.data,
  92                               blob.length,
  93                               hash);
  94         if (rc < 0) {
  95                 return NT_STATUS_INTERNAL_ERROR;
  96         }
  97
  98         return NT_STATUS_OK;
  99 }
 100
 101 /*******************************************************************
 102  Hash a security descriptor.
 103 *******************************************************************/
 104
 105 static NTSTATUS hash_sd_sha256(struct security_descriptor *psd,
 106                         uint8_t *hash)
 107 {
 108         DATA_BLOB blob;
 109         NTSTATUS status;
 110
 111         memset(hash, '\0', XATTR_SD_HASH_SIZE);
 112         status = create_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash);
 113         if (!NT_STATUS_IS_OK(status)) {
 114                 return status;
 115         }
 116         return hash_blob_sha256(blob, hash);
 117 }
 118
 119 /*******************************************************************
 120  Parse out a struct security_descriptor from a DATA_BLOB.
 121 *******************************************************************/
 122
 123 static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
 124                                TALLOC_CTX *mem_ctx,
 125                                struct security_descriptor **ppdesc,
 126                                uint16_t *p_hash_type,
 127                                uint16_t *p_version,
 128                                uint8_t hash[XATTR_SD_HASH_SIZE],
 129                                uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE])
 130 {
 131         struct xattr_NTACL xacl;
 132         enum ndr_err_code ndr_err;
 133         size_t sd_size;
 134         TALLOC_CTX *frame = talloc_stackframe();
 135
 136         ndr_err = ndr_pull_struct_blob(pblob, frame, &xacl,
 137                         (ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);
 138
 139         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 140                 DBG_INFO("ndr_pull_xattr_NTACL failed: %s\n",
 141                          ndr_errstr(ndr_err));
 142                 TALLOC_FREE(frame);
 143                 return ndr_map_error2ntstatus(ndr_err);
 144         }
 145
 146         *p_version = xacl.version;
 147
 148         switch (xacl.version) {
 149                 case 1:
 150                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 151                                         xacl.info.sd->type | SEC_DESC_SELF_RELATIVE,
 152                                         xacl.info.sd->owner_sid,
 153                                         xacl.info.sd->group_sid,
 154                                         xacl.info.sd->sacl,
 155                                         xacl.info.sd->dacl,
 156                                         &sd_size);
 157                         /* No hash - null out. */
 158                         *p_hash_type = XATTR_SD_HASH_TYPE_NONE;
 159                         memset(hash, '\0', XATTR_SD_HASH_SIZE);
 160                         break;
 161                 case 2:
 162                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 163                                         xacl.info.sd_hs2->sd->type | SEC_DESC_SELF_RELATIVE,
 164                                         xacl.info.sd_hs2->sd->owner_sid,
 165                                         xacl.info.sd_hs2->sd->group_sid,
 166                                         xacl.info.sd_hs2->sd->sacl,
 167                                         xacl.info.sd_hs2->sd->dacl,
 168                                         &sd_size);
 169                         /* No hash - null out. */
 170                         *p_hash_type = XATTR_SD_HASH_TYPE_NONE;
 171                         memset(hash, '\0', XATTR_SD_HASH_SIZE);
 172                         break;
 173                 case 3:
 174                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 175                                         xacl.info.sd_hs3->sd->type | SEC_DESC_SELF_RELATIVE,
 176                                         xacl.info.sd_hs3->sd->owner_sid,
 177                                         xacl.info.sd_hs3->sd->group_sid,
 178                                         xacl.info.sd_hs3->sd->sacl,
 179                                         xacl.info.sd_hs3->sd->dacl,
 180                                         &sd_size);
 181                         *p_hash_type = xacl.info.sd_hs3->hash_type;
 182                         /* Current version 3 (if no sys acl hash available). */
 183                         memcpy(hash, xacl.info.sd_hs3->hash, XATTR_SD_HASH_SIZE);
 184                         break;
 185                 case 4:
 186                         *ppdesc = make_sec_desc(mem_ctx, SD_REVISION,
 187                                         xacl.info.sd_hs4->sd->type | SEC_DESC_SELF_RELATIVE,
 188                                         xacl.info.sd_hs4->sd->owner_sid,
 189                                         xacl.info.sd_hs4->sd->group_sid,
 190                                         xacl.info.sd_hs4->sd->sacl,
 191                                         xacl.info.sd_hs4->sd->dacl,
 192                                         &sd_size);
 193                         *p_hash_type = xacl.info.sd_hs4->hash_type;
 194                         /* Current version 4. */
 195                         memcpy(hash, xacl.info.sd_hs4->hash, XATTR_SD_HASH_SIZE);
 196                         memcpy(sys_acl_hash, xacl.info.sd_hs4->sys_acl_hash, XATTR_SD_HASH_SIZE);
 197                         break;
 198                 default:
 199                         TALLOC_FREE(frame);
 200                         return NT_STATUS_REVISION_MISMATCH;
 201         }
 202
 203         TALLOC_FREE(frame);
 204
 205         return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
 206 }
 207
 208 /*******************************************************************
 209  Create a DATA_BLOB from a hash of the security descriptor storead at
 210  the system layer and the NT ACL we wish to preserve
 211 *******************************************************************/
 212
 213 static NTSTATUS create_acl_blob(const struct security_descriptor *psd,
 214                         DATA_BLOB *pblob,
 215                         uint16_t hash_type,
 216                         uint8_t hash[XATTR_SD_HASH_SIZE])
 217 {
 218         struct xattr_NTACL xacl;
 219         struct security_descriptor_hash_v3 sd_hs3;
 220         enum ndr_err_code ndr_err;
 221         TALLOC_CTX *ctx = talloc_tos();
 222
 223         ZERO_STRUCT(xacl);
 224         ZERO_STRUCT(sd_hs3);
 225
 226         xacl.version = 3;
 227         xacl.info.sd_hs3 = &sd_hs3;
 228         xacl.info.sd_hs3->sd = discard_const_p(struct security_descriptor, psd);
 229         xacl.info.sd_hs3->hash_type = hash_type;
 230         memcpy(&xacl.info.sd_hs3->hash[0], hash, XATTR_SD_HASH_SIZE);
 231
 232         ndr_err = ndr_push_struct_blob(
 233                         pblob, ctx, &xacl,
 234                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 235
 236         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 237                 DBG_INFO("ndr_push_xattr_NTACL failed: %s\n",
 238                          ndr_errstr(ndr_err));
 239                 return ndr_map_error2ntstatus(ndr_err);
 240         }
 241
 242         return NT_STATUS_OK;
 243 }
 244
 245 /*******************************************************************
 246  Create a DATA_BLOB from a hash of the security descriptors
 247  (system and NT) stored at the system layer and the NT ACL we wish
 248  to preserve.
 249 *******************************************************************/
 250
 251 static NTSTATUS create_sys_acl_blob(const struct security_descriptor *psd,
 252                                     DATA_BLOB *pblob,
 253                                     uint16_t hash_type,
 254                                     uint8_t hash[XATTR_SD_HASH_SIZE],
 255                                     const char *description,
 256                                     uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE])
 257 {
 258         struct xattr_NTACL xacl;
 259         struct security_descriptor_hash_v4 sd_hs4;
 260         enum ndr_err_code ndr_err;
 261         TALLOC_CTX *ctx = talloc_tos();
 262
 263         ZERO_STRUCT(xacl);
 264         ZERO_STRUCT(sd_hs4);
 265
 266         xacl.version = 4;
 267         xacl.info.sd_hs4 = &sd_hs4;
 268         xacl.info.sd_hs4->sd = discard_const_p(struct security_descriptor, psd);
 269         xacl.info.sd_hs4->hash_type = hash_type;
 270         memcpy(&xacl.info.sd_hs4->hash[0], hash, XATTR_SD_HASH_SIZE);
 271         xacl.info.sd_hs4->description = description;
 272         memcpy(&xacl.info.sd_hs4->sys_acl_hash[0], sys_acl_hash, XATTR_SD_HASH_SIZE);
 273
 274         ndr_err = ndr_push_struct_blob(
 275                         pblob, ctx, &xacl,
 276                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 277
 278         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 279                 DBG_INFO("ndr_push_xattr_NTACL failed: %s\n",
 280                          ndr_errstr(ndr_err));
 281                 return ndr_map_error2ntstatus(ndr_err);
 282         }
 283
 284         return NT_STATUS_OK;
 285 }
 286
 287 /*******************************************************************
 288  Add in 3 inheritable components for a non-inheritable directory ACL.
 289  CREATOR_OWNER/CREATOR_GROUP/WORLD.
 290 *******************************************************************/
 291
 292 static NTSTATUS add_directory_inheritable_components(vfs_handle_struct *handle,
 293                                 const char *name,
 294                                 SMB_STRUCT_STAT *psbuf,
 295                                 struct security_descriptor *psd)
 296 {
 297         struct connection_struct *conn = handle->conn;
 298         int num_aces = (psd->dacl ? psd->dacl->num_aces : 0);
 299         struct smb_filename smb_fname;
 300         enum security_ace_type acltype;
 301         uint32_t access_mask;
 302         mode_t dir_mode;
 303         mode_t file_mode;
 304         mode_t mode;
 305         struct security_ace *new_ace_list;
 306
 307         if (psd->dacl) {
 308                 new_ace_list = talloc_zero_array(psd->dacl,
 309                                                  struct security_ace,
 310                                                  num_aces + 3);
 311         } else {
 312                 /*
 313                  * make_sec_acl() at the bottom of this function
 314                  * duplicates new_ace_list
 315                  */
 316                 new_ace_list = talloc_zero_array(talloc_tos(),
 317                                                  struct security_ace,
 318                                                  num_aces + 3);
 319         }
 320
 321         if (new_ace_list == NULL) {
 322                 return NT_STATUS_NO_MEMORY;
 323         }
 324
 325         /* Fake a quick smb_filename. */
 326         ZERO_STRUCT(smb_fname);
 327         smb_fname.st = *psbuf;
 328         smb_fname.base_name = discard_const_p(char, name);
 329
 330         dir_mode = unix_mode(conn,
 331                         FILE_ATTRIBUTE_DIRECTORY, &smb_fname, NULL);
 332         file_mode = unix_mode(conn,
 333                         FILE_ATTRIBUTE_ARCHIVE, &smb_fname, NULL);
 334
 335         mode = dir_mode | file_mode;
 336
 337         DBG_DEBUG("directory %s, mode = 0%o\n", name, (unsigned int)mode);
 338
 339         if (num_aces) {
 340                 memcpy(new_ace_list, psd->dacl->aces,
 341                         num_aces * sizeof(struct security_ace));
 342         }
 343         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 344                                 mode & 0700, false);
 345
 346         init_sec_ace(&new_ace_list[num_aces],
 347                         &global_sid_Creator_Owner,
 348                         acltype,
 349                         access_mask,
 350                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 351                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 352                                 SEC_ACE_FLAG_INHERIT_ONLY);
 353         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 354                                 (mode << 3) & 0700, false);
 355         init_sec_ace(&new_ace_list[num_aces+1],
 356                         &global_sid_Creator_Group,
 357                         acltype,
 358                         access_mask,
 359                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 360                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 361                                 SEC_ACE_FLAG_INHERIT_ONLY);
 362         access_mask = map_canon_ace_perms(SNUM(conn), &acltype,
 363                                 (mode << 6) & 0700, false);
 364         init_sec_ace(&new_ace_list[num_aces+2],
 365                         &global_sid_World,
 366                         acltype,
 367                         access_mask,
 368                         SEC_ACE_FLAG_CONTAINER_INHERIT|
 369                                 SEC_ACE_FLAG_OBJECT_INHERIT|
 370                                 SEC_ACE_FLAG_INHERIT_ONLY);
 371         if (psd->dacl) {
 372                 psd->dacl->aces = new_ace_list;
 373                 psd->dacl->num_aces += 3;
 374                 psd->dacl->size += new_ace_list[num_aces].size +
 375                         new_ace_list[num_aces+1].size +
 376                         new_ace_list[num_aces+2].size;
 377         } else {
 378                 psd->dacl = make_sec_acl(psd,
 379                                 NT4_ACL_REVISION,
 380                                 3,
 381                                 new_ace_list);
 382                 if (psd->dacl == NULL) {
 383                         return NT_STATUS_NO_MEMORY;
 384                 }
 385         }
 386         return NT_STATUS_OK;
 387 }
 388
 389 /**
 390  * Validate an ACL blob
 391  *
 392  * This validates an ACL blob against the underlying filesystem ACL. If this
 393  * function returns NT_STATUS_OK ppsd can be
 394  *
 395  * 1. the ACL from the blob (psd_from_fs=false), or
 396  * 2. the ACL from the fs (psd_from_fs=true), or
 397  * 3. NULL (!)
 398  *
 399  * If the return value is anything else then NT_STATUS_OK, ppsd is set to NULL
 400  * and psd_from_fs set to false.
 401  *
 402  * Returning the underlying filesystem ACL in case no. 2 is really just an
 403  * optimisation, because some validations have to fetch the filesystem ACL as
 404  * part of the validation, so we already have it available and callers might
 405  * need it as well.
 406  **/
 407 static NTSTATUS validate_nt_acl_blob(TALLOC_CTX *mem_ctx,
 408                                 vfs_handle_struct *handle,
 409                                 struct files_struct *fsp,
 410                                 const struct smb_filename *smb_fname,
 411                                 const DATA_BLOB *blob,
 412                                 struct security_descriptor **ppsd,
 413                                 bool *psd_is_from_fs)
 414 {
 415         NTSTATUS status;
 416         uint16_t hash_type = XATTR_SD_HASH_TYPE_NONE;
 417         uint16_t xattr_version = 0;
 418         uint8_t hash[XATTR_SD_HASH_SIZE];
 419         uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE];
 420         uint8_t hash_tmp[XATTR_SD_HASH_SIZE];
 421         uint8_t sys_acl_hash_tmp[XATTR_SD_HASH_SIZE];
 422         struct security_descriptor *psd = NULL;
 423         struct security_descriptor *psd_blob = NULL;
 424         struct security_descriptor *psd_fs = NULL;
 425         char *sys_acl_blob_description = NULL;
 426         DATA_BLOB sys_acl_blob = { 0 };
 427         struct acl_common_config *config = NULL;
 428
 429         *ppsd = NULL;
 430         *psd_is_from_fs = false;
 431
 432         SMB_VFS_HANDLE_GET_DATA(handle, config,
 433                                 struct acl_common_config,
 434                                 return NT_STATUS_UNSUCCESSFUL);
 435
 436         status = parse_acl_blob(blob,
 437                                 mem_ctx,
 438                                 &psd_blob,
 439                                 &hash_type,
 440                                 &xattr_version,
 441                                 &hash[0],
 442                                 &sys_acl_hash[0]);
 443         if (!NT_STATUS_IS_OK(status)) {
 444                 DBG_DEBUG("parse_acl_blob returned %s\n", nt_errstr(status));
 445                 goto fail;
 446         }
 447
 448         /* determine which type of xattr we got */
 449         switch (xattr_version) {
 450         case 1:
 451         case 2:
 452                 /* These xattr types are unilateral, they do not
 453                  * require confirmation of the hash.  In particular,
 454                  * the NTVFS file server uses version 1, but
 455                  * 'samba-tool ntacl' can set these as well */
 456                 *ppsd = psd_blob;
 457                 return NT_STATUS_OK;
 458         case 3:
 459         case 4:
 460                 if (config->ignore_system_acls) {
 461                         *ppsd = psd_blob;
 462                         return NT_STATUS_OK;
 463                 }
 464
 465                 break;
 466         default:
 467                 DBG_DEBUG("ACL blob revision mismatch (%u) for file %s\n",
 468                           (unsigned int)hash_type, smb_fname->base_name);
 469                 TALLOC_FREE(psd_blob);
 470                 return NT_STATUS_OK;
 471         }
 472
 473         /* determine which type of xattr we got */
 474         if (hash_type != XATTR_SD_HASH_TYPE_SHA256) {
 475                 DBG_DEBUG("ACL blob hash type (%u) unexpected for file %s\n",
 476                           (unsigned int)hash_type, smb_fname->base_name);
 477                 TALLOC_FREE(psd_blob);
 478                 return NT_STATUS_OK;
 479         }
 480
 481         /* determine which type of xattr we got */
 482         switch (xattr_version) {
 483         case 4:
 484         {
 485                 int ret;
 486                 /* Get the full underlying sd, then hash. */
 487                 ret = SMB_VFS_NEXT_SYS_ACL_BLOB_GET_FD(handle,
 488                                                        fsp,
 489                                                        mem_ctx,
 490                                                        &sys_acl_blob_description,
 491                                                        &sys_acl_blob);
 492                 /* If we fail to get the ACL blob (for some reason) then this
 493                  * is not fatal, we just work based on the NT ACL only */
 494                 if (ret == 0) {
 495                         status = hash_blob_sha256(sys_acl_blob, sys_acl_hash_tmp);
 496                         if (!NT_STATUS_IS_OK(status)) {
 497                                 goto fail;
 498                         }
 499
 500                         TALLOC_FREE(sys_acl_blob_description);
 501                         TALLOC_FREE(sys_acl_blob.data);
 502
 503                         if (memcmp(&sys_acl_hash[0], &sys_acl_hash_tmp[0],
 504                                    XATTR_SD_HASH_SIZE) == 0) {
 505                                 /* Hash matches, return blob sd. */
 506                                 DBG_DEBUG("blob hash matches for file %s\n",
 507                                           smb_fname->base_name);
 508                                 *ppsd = psd_blob;
 509                                 return NT_STATUS_OK;
 510                         }
 511                 }
 512
 513                 /* Otherwise, fall though and see if the NT ACL hash matches */
 514                 FALL_THROUGH;
 515         }
 516         case 3:
 517                 /* Get the full underlying sd for the hash
 518                    or to return as backup. */
 519                 status = SMB_VFS_NEXT_FGET_NT_ACL(handle,
 520                                                   fsp,
 521                                                   HASH_SECURITY_INFO,
 522                                                   mem_ctx,
 523                                                   &psd_fs);
 524                 if (!NT_STATUS_IS_OK(status)) {
 525                         DBG_DEBUG("get_next_acl for file %s returned %s\n",
 526                                   smb_fname->base_name, nt_errstr(status));
 527                         goto fail;
 528                 }
 529
 530                 status = hash_sd_sha256(psd_fs, hash_tmp);
 531                 if (!NT_STATUS_IS_OK(status)) {
 532                         TALLOC_FREE(psd_blob);
 533                         *ppsd = psd_fs;
 534                         *psd_is_from_fs = true;
 535                         return NT_STATUS_OK;
 536                 }
 537
 538                 if (memcmp(&hash[0], &hash_tmp[0], XATTR_SD_HASH_SIZE) == 0) {
 539                         /* Hash matches, return blob sd. */
 540                         DBG_DEBUG("blob hash matches for file %s\n",
 541                                   smb_fname->base_name);
 542                         *ppsd = psd_blob;
 543                         return NT_STATUS_OK;
 544                 }
 545
 546                 /* Hash doesn't match, return underlying sd. */
 547                 DBG_DEBUG("blob hash does not match for file %s - returning "
 548                           "file system SD mapping.\n",
 549                           smb_fname->base_name);
 550
 551                 if (DEBUGLEVEL >= 10) {
 552                         DBG_DEBUG("acl for blob hash for %s is:\n",
 553                                   smb_fname->base_name);
 554                         NDR_PRINT_DEBUG(security_descriptor, psd_fs);
 555                 }
 556
 557                 TALLOC_FREE(psd_blob);
 558                 *ppsd = psd_fs;
 559                 *psd_is_from_fs = true;
 560         }
 561
 562         return NT_STATUS_OK;
 563
 564 fail:
 565         TALLOC_FREE(psd);
 566         TALLOC_FREE(psd_blob);
 567         TALLOC_FREE(psd_fs);
 568         TALLOC_FREE(sys_acl_blob_description);
 569         TALLOC_FREE(sys_acl_blob.data);
 570         return status;
 571 }
 572
 573 /*******************************************************************
 574  Pull a DATA_BLOB from an xattr given an fsp.
 575  If the hash doesn't match, or doesn't exist - return the underlying
 576  filesystem sd.
 577 *******************************************************************/
 578
 579 NTSTATUS fget_nt_acl_common(
 580         NTSTATUS (*fget_acl_blob_fn)(TALLOC_CTX *ctx,
 581                                     vfs_handle_struct *handle,
 582                                     files_struct *fsp,
 583                                     DATA_BLOB *pblob),
 584         vfs_handle_struct *handle,
 585         files_struct *fsp,
 586         uint32_t security_info,
 587         TALLOC_CTX *mem_ctx,
 588         struct security_descriptor **ppdesc)
 589 {
 590         DATA_BLOB blob = data_blob_null;
 591         NTSTATUS status;
 592         struct security_descriptor *psd = NULL;
 593         const struct smb_filename *smb_fname = fsp->fsp_name;
 594         bool psd_is_from_fs = false;
 595         struct acl_common_config *config = NULL;
 596
 597         SMB_VFS_HANDLE_GET_DATA(handle, config,
 598                                 struct acl_common_config,
 599                                 return NT_STATUS_UNSUCCESSFUL);
 600
 601         DBG_DEBUG("name=%s\n", smb_fname->base_name);
 602
 603         status = fget_acl_blob_fn(mem_ctx, handle, fsp, &blob);
 604         if (NT_STATUS_IS_OK(status)) {
 605                 status = validate_nt_acl_blob(mem_ctx,
 606                                         handle,
 607                                         fsp,
 608                                         smb_fname,
 609                                         &blob,
 610                                         &psd,
 611                                         &psd_is_from_fs);
 612                 TALLOC_FREE(blob.data);
 613                 if (!NT_STATUS_IS_OK(status)) {
 614                         DBG_DEBUG("ACL validation for [%s] failed\n",
 615                                   smb_fname->base_name);
 616                         goto fail;
 617                 }
 618         }
 619
 620         if (psd == NULL) {
 621                 /* Get the full underlying sd, as we failed to get the
 622                  * blob for the hash, or the revision/hash type wasn't
 623                  * known */
 624
 625                 if (config->ignore_system_acls) {
 626                         status = vfs_stat_fsp(fsp);
 627                         if (!NT_STATUS_IS_OK(status)) {
 628                                 goto fail;
 629                         }
 630
 631                         status = make_default_filesystem_acl(
 632                                 mem_ctx,
 633                                 config->default_acl_style,
 634                                 smb_fname->base_name,
 635                                 &fsp->fsp_name->st,
 636                                 &psd);
 637                         if (!NT_STATUS_IS_OK(status)) {
 638                                 goto fail;
 639                         }
 640                 } else {
 641                         status = SMB_VFS_NEXT_FGET_NT_ACL(handle,
 642                                                           fsp,
 643                                                           security_info,
 644                                                           mem_ctx,
 645                                                           &psd);
 646
 647                         if (!NT_STATUS_IS_OK(status)) {
 648                                 DBG_DEBUG("get_next_acl for file %s "
 649                                           "returned %s\n",
 650                                           smb_fname->base_name,
 651                                           nt_errstr(status));
 652                                 goto fail;
 653                         }
 654
 655                         psd_is_from_fs = true;
 656                 }
 657         }
 658
 659         if (psd_is_from_fs) {
 660                 status = vfs_stat_fsp(fsp);
 661                 if (!NT_STATUS_IS_OK(status)) {
 662                         goto fail;
 663                 }
 664
 665                 /*
 666                  * We're returning the underlying ACL from the
 667                  * filesystem. If it's a directory, and has no
 668                  * inheritable ACE entries we have to fake them.
 669                  */
 670
 671                 if (fsp->fsp_flags.is_directory &&
 672                                 !sd_has_inheritable_components(psd, true)) {
 673                         status = add_directory_inheritable_components(
 674                                 handle,
 675                                 smb_fname->base_name,
 676                                 &fsp->fsp_name->st,
 677                                 psd);
 678                         if (!NT_STATUS_IS_OK(status)) {
 679                                 goto fail;
 680                         }
 681                 }
 682
 683                 /*
 684                  * The underlying POSIX module always sets the
 685                  * ~SEC_DESC_DACL_PROTECTED bit, as ACLs can't be inherited in
 686                  * this way under POSIX. Remove it for Windows-style ACLs.
 687                  */
 688                 psd->type &= ~SEC_DESC_DACL_PROTECTED;
 689         }
 690
 691         if (!(security_info & SECINFO_OWNER)) {
 692                 psd->owner_sid = NULL;
 693         }
 694         if (!(security_info & SECINFO_GROUP)) {
 695                 psd->group_sid = NULL;
 696         }
 697         if (!(security_info & SECINFO_DACL)) {
 698                 psd->type &= ~SEC_DESC_DACL_PRESENT;
 699                 psd->dacl = NULL;
 700         }
 701         if (!(security_info & SECINFO_SACL)) {
 702                 psd->type &= ~SEC_DESC_SACL_PRESENT;
 703                 psd->sacl = NULL;
 704         }
 705
 706         if (DEBUGLEVEL >= 10) {
 707                 DBG_DEBUG("returning acl for %s is:\n",
 708                           smb_fname->base_name);
 709                 NDR_PRINT_DEBUG(security_descriptor, psd);
 710         }
 711
 712         *ppdesc = psd;
 713
 714         return NT_STATUS_OK;
 715
 716 fail:
 717         TALLOC_FREE(psd);
 718         return status;
 719 }
 720
 721 /*********************************************************************
 722  Set the underlying ACL (e.g. POSIX ACLS, POSIX owner, etc)
 723 *********************************************************************/
 724 static NTSTATUS set_underlying_acl(vfs_handle_struct *handle, files_struct *fsp,
 725                                    struct security_descriptor *psd,
 726                                    uint32_t security_info_sent,
 727                                    bool chown_needed)
 728 {
 729         NTSTATUS status;
 730         const struct security_token *token = NULL;
 731         struct dom_sid_buf buf;
 732
 733         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
 734         if (!NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 735                 return status;
 736         }
 737
 738         /* We got access denied here. If we're already root,
 739            or we didn't need to do a chown, or the fsp isn't
 740            open with WRITE_OWNER access, just return. */
 741         if (get_current_uid(handle->conn) == 0 || !chown_needed) {
 742                 return NT_STATUS_ACCESS_DENIED;
 743         }
 744         status = check_any_access_fsp(fsp, SEC_STD_WRITE_OWNER);
 745         if (!NT_STATUS_IS_OK(status)) {
 746                 return status;
 747         }
 748
 749         /*
 750          * Only allow take-ownership, not give-ownership. That's the way Windows
 751          * implements SEC_STD_WRITE_OWNER. MS-FSA 2.1.5.16 just states: If
 752          * InputBuffer.OwnerSid is not a valid owner SID for a file in the
 753          * objectstore, as determined in an implementation specific manner, the
 754          * object store MUST return STATUS_INVALID_OWNER.
 755          */
 756         token = get_current_nttok(fsp->conn);
 757         if (!security_token_is_sid(token, psd->owner_sid)) {
 758                 return NT_STATUS_INVALID_OWNER;
 759         }
 760
 761         DBG_DEBUG("overriding chown on file %s for sid %s\n",
 762                   fsp_str_dbg(fsp),
 763                   dom_sid_str_buf(psd->owner_sid, &buf));
 764
 765         /* Ok, we failed to chown and we have
 766            SEC_STD_WRITE_OWNER access - override. */
 767         become_root();
 768         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
 769         unbecome_root();
 770
 771         return status;
 772 }
 773
 774 /*********************************************************************
 775  Store a v3 security descriptor
 776 *********************************************************************/
 777 static NTSTATUS store_v3_blob(
 778         NTSTATUS (*store_acl_blob_fsp_fn)(vfs_handle_struct *handle,
 779                                           files_struct *fsp,
 780                                           DATA_BLOB *pblob),
 781         vfs_handle_struct *handle, files_struct *fsp,
 782         struct security_descriptor *psd,
 783         struct security_descriptor *pdesc_next,
 784         uint8_t hash[XATTR_SD_HASH_SIZE])
 785 {
 786         NTSTATUS status;
 787         DATA_BLOB blob;
 788
 789         if (DEBUGLEVEL >= 10) {
 790                 DBG_DEBUG("storing xattr sd for file %s\n",
 791                           fsp_str_dbg(fsp));
 792                 NDR_PRINT_DEBUG(
 793                     security_descriptor,
 794                     discard_const_p(struct security_descriptor, psd));
 795
 796                 if (pdesc_next != NULL) {
 797                         DBG_DEBUG("storing xattr sd based on \n");
 798                         NDR_PRINT_DEBUG(
 799                             security_descriptor,
 800                             discard_const_p(struct security_descriptor,
 801                                             pdesc_next));
 802                 } else {
 803                         DBG_DEBUG("ignoring underlying sd\n");
 804                 }
 805         }
 806         status = create_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash);
 807         if (!NT_STATUS_IS_OK(status)) {
 808                 DBG_DEBUG("create_acl_blob failed\n");
 809                 return status;
 810         }
 811
 812         status = store_acl_blob_fsp_fn(handle, fsp, &blob);
 813         return status;
 814 }
 815
 816 /*********************************************************************
 817  Store a security descriptor given an fsp.
 818 *********************************************************************/
 819
 820 NTSTATUS fset_nt_acl_common(
 821         NTSTATUS (*fget_acl_blob_fn)(TALLOC_CTX *ctx,
 822                                     vfs_handle_struct *handle,
 823                                     files_struct *fsp,
 824                                     DATA_BLOB *pblob),
 825         NTSTATUS (*store_acl_blob_fsp_fn)(vfs_handle_struct *handle,
 826                                           files_struct *fsp,
 827                                           DATA_BLOB *pblob),
 828         const char *module_name,
 829         vfs_handle_struct *handle, files_struct *fsp,
 830         uint32_t security_info_sent,
 831         const struct security_descriptor *orig_psd)
 832 {
 833         NTSTATUS status;
 834         int ret;
 835         DATA_BLOB blob, sys_acl_blob;
 836         struct security_descriptor *pdesc_next = NULL;
 837         struct security_descriptor *psd = NULL;
 838         uint8_t hash[XATTR_SD_HASH_SIZE];
 839         uint8_t sys_acl_hash[XATTR_SD_HASH_SIZE];
 840         bool chown_needed = false;
 841         char *sys_acl_description;
 842         TALLOC_CTX *frame = talloc_stackframe();
 843         bool ignore_file_system_acl = lp_parm_bool(
 844             SNUM(handle->conn), module_name, "ignore system acls", false);
 845         struct acl_common_fsp_ext *ext = NULL;
 846
 847         if (DEBUGLEVEL >= 10) {
 848                 DBG_DEBUG("incoming sd for file %s\n", fsp_str_dbg(fsp));
 849                 NDR_PRINT_DEBUG(security_descriptor,
 850                         discard_const_p(struct security_descriptor, orig_psd));
 851         }
 852
 853         status = fget_nt_acl_common(fget_acl_blob_fn, handle, fsp,
 854                         SECINFO_OWNER|SECINFO_GROUP|SECINFO_DACL|SECINFO_SACL,
 855                                      frame,
 856                         &psd);
 857
 858         if (!NT_STATUS_IS_OK(status)) {
 859                 TALLOC_FREE(frame);
 860                 return status;
 861         }
 862
 863         psd->revision = orig_psd->revision;
 864         if (security_info_sent & SECINFO_DACL) {
 865                 psd->type = orig_psd->type;
 866                 /* All our SD's are self relative. */
 867                 psd->type |= SEC_DESC_SELF_RELATIVE;
 868         }
 869
 870         if ((security_info_sent & SECINFO_OWNER) && (orig_psd->owner_sid != NULL)) {
 871                 if (!dom_sid_equal(orig_psd->owner_sid, psd->owner_sid)) {
 872                         /* We're changing the owner. */
 873                         chown_needed = true;
 874                 }
 875                 psd->owner_sid = orig_psd->owner_sid;
 876         }
 877         if ((security_info_sent & SECINFO_GROUP) && (orig_psd->group_sid != NULL)) {
 878                 if (!dom_sid_equal(orig_psd->group_sid, psd->group_sid)) {
 879                         /* We're changing the group. */
 880                         chown_needed = true;
 881                 }
 882                 psd->group_sid = orig_psd->group_sid;
 883         }
 884         if (security_info_sent & SECINFO_DACL) {
 885                 if (security_descriptor_with_ms_nfs(orig_psd)) {
 886                         /*
 887                          * If the sd contains a MS NFS SID, do
 888                          * nothing, it's a chmod() request from OS X
 889                          * with AAPL context.
 890                          */
 891                         TALLOC_FREE(frame);
 892                         return NT_STATUS_OK;
 893                 }
 894                 psd->dacl = orig_psd->dacl;
 895                 psd->type |= SEC_DESC_DACL_PRESENT;
 896         }
 897         if (security_info_sent & SECINFO_SACL) {
 898                 psd->sacl = orig_psd->sacl;
 899                 psd->type |= SEC_DESC_SACL_PRESENT;
 900         }
 901
 902         ext = VFS_ADD_FSP_EXTENSION(handle,
 903                                     fsp,
 904                                     struct acl_common_fsp_ext,
 905                                     NULL);
 906         ext->setting_nt_acl = true;
 907
 908         if (ignore_file_system_acl) {
 909                 if (chown_needed) {
 910                         /* send only ownership stuff to lower layer */
 911                         security_info_sent &= (SECINFO_OWNER | SECINFO_GROUP);
 912                         status = set_underlying_acl(handle, fsp, psd,
 913                                                     security_info_sent, true);
 914                         if (!NT_STATUS_IS_OK(status)) {
 915                                 goto done;
 916                         }
 917                 }
 918                 ZERO_ARRAY(hash);
 919                 status = store_v3_blob(store_acl_blob_fsp_fn, handle, fsp, psd,
 920                                        NULL, hash);
 921                 goto done;
 922         }
 923
 924         status = set_underlying_acl(handle, fsp, psd, security_info_sent,
 925                                     chown_needed);
 926         if (!NT_STATUS_IS_OK(status)) {
 927                 goto done;
 928         }
 929
 930         /* Get the full underlying sd, then hash. */
 931         status = SMB_VFS_NEXT_FGET_NT_ACL(handle,
 932                                           fsp,
 933                                           HASH_SECURITY_INFO,
 934                                           frame,
 935                                           &pdesc_next);
 936
 937         if (!NT_STATUS_IS_OK(status)) {
 938                 goto done;
 939         }
 940
 941         status = hash_sd_sha256(pdesc_next, hash);
 942         if (!NT_STATUS_IS_OK(status)) {
 943                 goto done;
 944         }
 945
 946         /* Get the full underlying sd, then hash. */
 947         ret = SMB_VFS_NEXT_SYS_ACL_BLOB_GET_FD(handle,
 948                                                fsp,
 949                                                frame,
 950                                                &sys_acl_description,
 951                                                &sys_acl_blob);
 952
 953         /* If we fail to get the ACL blob (for some reason) then this
 954          * is not fatal, we just work based on the NT ACL only */
 955         if (ret != 0) {
 956                 status = store_v3_blob(store_acl_blob_fsp_fn, handle, fsp, psd,
 957                                        pdesc_next, hash);
 958
 959                 goto done;
 960         }
 961
 962         status = hash_blob_sha256(sys_acl_blob, sys_acl_hash);
 963         if (!NT_STATUS_IS_OK(status)) {
 964                 goto done;
 965         }
 966
 967         if (DEBUGLEVEL >= 10) {
 968                 DBG_DEBUG("storing xattr sd for file %s based on system ACL\n",
 969                           fsp_str_dbg(fsp));
 970                 NDR_PRINT_DEBUG(security_descriptor,
 971                                 discard_const_p(struct security_descriptor, psd));
 972
 973                 DBG_DEBUG("storing hash in xattr sd based on system ACL and:\n");
 974                 NDR_PRINT_DEBUG(security_descriptor,
 975                                 discard_const_p(struct security_descriptor, pdesc_next));
 976         }
 977
 978         /* We store hashes of both the sys ACL blob and the NT
 979          * security descriptor mapped from that ACL so as to improve
 980          * our chances against some inadvertent change breaking the
 981          * hash used */
 982         status = create_sys_acl_blob(psd, &blob, XATTR_SD_HASH_TYPE_SHA256, hash,
 983                                      sys_acl_description, sys_acl_hash);
 984         if (!NT_STATUS_IS_OK(status)) {
 985                 DBG_DEBUG("create_sys_acl_blob failed\n");
 986                 goto done;
 987         }
 988
 989         status = store_acl_blob_fsp_fn(handle, fsp, &blob);
 990
 991 done:
 992         VFS_REMOVE_FSP_EXTENSION(handle, fsp);
 993         TALLOC_FREE(frame);
 994         return status;
 995 }
 996
 997 static int acl_common_remove_object(vfs_handle_struct *handle,
 998                                         struct files_struct *dirfsp,
 999                                         const struct smb_filename *smb_fname,
1000                                         bool is_directory)
1001 {
1002         connection_struct *conn = handle->conn;
1003         struct file_id id;
1004         files_struct *fsp = NULL;
1005         int ret = 0;
1006         struct smb_filename *full_fname = NULL;
1007         struct smb_filename *local_fname = NULL;
1008         struct smb_filename *parent_dir_fname = NULL;
1009         int saved_errno = 0;
1010         struct smb_filename *saved_dir_fname = NULL;
1011         NTSTATUS status;
1012
1013         saved_dir_fname = vfs_GetWd(talloc_tos(),conn);
1014         if (saved_dir_fname == NULL) {
1015                 saved_errno = errno;
1016                 goto out;
1017         }
1018
1019         full_fname = full_path_from_dirfsp_atname(talloc_tos(),
1020                                                   dirfsp,
1021                                                   smb_fname);
1022         if (full_fname == NULL) {
1023                 goto out;
1024         }
1025
1026         status = SMB_VFS_PARENT_PATHNAME(conn,
1027                                          talloc_tos(),
1028                                          full_fname,
1029                                          &parent_dir_fname,
1030                                          &local_fname);
1031         if (!NT_STATUS_IS_OK(status)) {
1032                 saved_errno = map_errno_from_nt_status(status);
1033                 goto out;
1034         }
1035
1036         DBG_DEBUG("removing %s %s\n", is_directory ? "directory" : "file",
1037                   smb_fname_str_dbg(full_fname));
1038
1039         /* cd into the parent dir to pin it. */
1040         ret = vfs_ChDir(conn, parent_dir_fname);
1041         if (ret == -1) {
1042                 saved_errno = errno;
1043                 goto out;
1044         }
1045
1046         /* Must use lstat here. */
1047         ret = SMB_VFS_LSTAT(conn, local_fname);
1048         if (ret == -1) {
1049                 saved_errno = errno;
1050                 goto out;
1051         }
1052
1053         /* Ensure we have this file open with DELETE access. */
1054         id = vfs_file_id_from_sbuf(conn, &local_fname->st);
1055         for (fsp = file_find_di_first(conn->sconn, id, true); fsp;
1056                      fsp = file_find_di_next(fsp, true)) {
1057                 if (fsp->access_mask & DELETE_ACCESS &&
1058                     fsp->fsp_flags.delete_on_close)
1059                 {
1060                         /* We did open this for delete,
1061                          * allow the delete as root.
1062                          */
1063                         break;
1064                 }
1065         }
1066
1067         if (!fsp) {
1068                 DBG_DEBUG("%s %s not an open file\n",
1069                           is_directory ? "directory" : "file",
1070                           smb_fname_str_dbg(full_fname));
1071                 saved_errno = EACCES;
1072                 goto out;
1073         }
1074
1075         become_root();
1076         if (is_directory) {
1077                 ret = SMB_VFS_NEXT_UNLINKAT(handle,
1078                                 dirfsp,
1079                                 smb_fname,
1080                                 AT_REMOVEDIR);
1081         } else {
1082                 ret = SMB_VFS_NEXT_UNLINKAT(handle,
1083                                 dirfsp,
1084                                 smb_fname,
1085                                 0);
1086         }
1087         unbecome_root();
1088
1089         if (ret == -1) {
1090                 saved_errno = errno;
1091         }
1092
1093   out:
1094
1095         TALLOC_FREE(parent_dir_fname);
1096         TALLOC_FREE(full_fname);
1097
1098         if (saved_dir_fname) {
1099                 vfs_ChDir(conn, saved_dir_fname);
1100                 TALLOC_FREE(saved_dir_fname);
1101         }
1102         if (saved_errno) {
1103                 errno = saved_errno;
1104         }
1105         return ret;
1106 }
1107
1108 int rmdir_acl_common(struct vfs_handle_struct *handle,
1109                 struct files_struct *dirfsp,
1110                 const struct smb_filename *smb_fname)
1111 {
1112         int ret;
1113
1114         /* Try the normal rmdir first. */
1115         ret = SMB_VFS_NEXT_UNLINKAT(handle,
1116                         dirfsp,
1117                         smb_fname,
1118                         AT_REMOVEDIR);
1119         if (ret == 0) {
1120                 return 0;
1121         }
1122         if (errno == EACCES || errno == EPERM) {
1123                 /* Failed due to access denied,
1124                    see if we need to root override. */
1125                 return acl_common_remove_object(handle,
1126                                                 dirfsp,
1127                                                 smb_fname,
1128                                                 true);
1129         }
1130
1131         DBG_DEBUG("unlink of %s failed %s\n",
1132                   smb_fname->base_name,
1133                   strerror(errno));
1134         return -1;
1135 }
1136
1137 int unlink_acl_common(struct vfs_handle_struct *handle,
1138                         struct files_struct *dirfsp,
1139                         const struct smb_filename *smb_fname,
1140                         int flags)
1141 {
1142         int ret;
1143
1144         /* Try the normal unlink first. */
1145         ret = SMB_VFS_NEXT_UNLINKAT(handle,
1146                                 dirfsp,
1147                                 smb_fname,
1148                                 flags);
1149         if (ret == 0) {
1150                 return 0;
1151         }
1152         if (errno == EACCES || errno == EPERM) {
1153                 /* Failed due to access denied,
1154                    see if we need to root override. */
1155
1156                 /* Don't do anything fancy for streams. */
1157                 if (smb_fname->stream_name) {
1158                         return -1;
1159                 }
1160                 return acl_common_remove_object(handle,
1161                                         dirfsp,
1162                                         smb_fname,
1163                                         false);
1164         }
1165
1166         DBG_DEBUG("unlink of %s failed %s\n",
1167                   smb_fname->base_name,
1168                   strerror(errno));
1169         return -1;
1170 }
1171
1172 int fchmod_acl_module_common(struct vfs_handle_struct *handle,
1173                              struct files_struct *fsp, mode_t mode)
1174 {
1175         if (fsp->posix_flags & FSP_POSIX_FLAGS_PATHNAMES
1176             || fsp->fsp_name->flags & SMB_FILENAME_POSIX_PATH) {
1177                 /* Only allow this on POSIX opens. */
1178                 return SMB_VFS_NEXT_FCHMOD(handle, fsp, mode);
1179         }
1180         return 0;
1181 }