source3/modules/vfs_acl_xattr.c

   1 /*
   2  * Store Windows ACLs in xattrs.
   3  *
   4  * Copyright (C) Volker Lendecke, 2008
   5  * Copyright (C) Jeremy Allison, 2008
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 /* NOTE: This is an experimental module, not yet finished. JRA. */
  22
  23 #include "includes.h"
  24 #include "librpc/gen_ndr/xattr.h"
  25 #include "librpc/gen_ndr/ndr_xattr.h"
  26
  27 #undef DBGC_CLASS
  28 #define DBGC_CLASS DBGC_VFS
  29
  30 static NTSTATUS parse_acl_blob(const DATA_BLOB *pblob,
  31                                 const struct timespec cts,
  32                                 uint32 security_info,
  33                                 struct security_descriptor **ppdesc)
  34 {
  35         TALLOC_CTX *ctx = talloc_tos();
  36         struct xattr_NTACL xacl;
  37         enum ndr_err_code ndr_err;
  38         size_t sd_size;
  39
  40         ndr_err = ndr_pull_struct_blob(pblob, ctx, NULL, &xacl,
  41                         (ndr_pull_flags_fn_t)ndr_pull_xattr_NTACL);
  42
  43         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  44                 DEBUG(5, ("parse_acl_blob: ndr_pull_xattr_NTACL failed: %s\n",
  45                         ndr_errstr(ndr_err)));
  46                 return ndr_map_error2ntstatus(ndr_err);;
  47         }
  48
  49         if (xacl.version != 2) {
  50                 return NT_STATUS_REVISION_MISMATCH;
  51         }
  52
  53 #if 0
  54         {
  55                 struct timespec ts;
  56                 /* Arg. This doesn't work. Too many activities
  57                  * change the ctime. May have to roll back to
  58                  * version 1.
  59                  */
  60                 /*
  61                  * Check that the ctime timestamp is ealier
  62                  * than the stored timestamp.
  63                  */
  64
  65                 ts = nt_time_to_unix_timespec(&xacl.info.sd_ts->last_changed);
  66
  67                 if (timespec_compare(&cts, &ts) > 0) {
  68                         DEBUG(5, ("parse_acl_blob: stored ACL out of date "
  69                                 "(%s > %s.\n",
  70                                 timestring(ctx, cts.tv_sec),
  71                                 timestring(ctx, ts.tv_sec)));
  72                         return NT_STATUS_EA_CORRUPT_ERROR;
  73                 }
  74         }
  75 #endif
  76
  77         *ppdesc = make_sec_desc(ctx, SEC_DESC_REVISION, SEC_DESC_SELF_RELATIVE,
  78                         (security_info & OWNER_SECURITY_INFORMATION)
  79                         ? xacl.info.sd_ts->sd->owner_sid : NULL,
  80                         (security_info & GROUP_SECURITY_INFORMATION)
  81                         ? xacl.info.sd_ts->sd->group_sid : NULL,
  82                         (security_info & SACL_SECURITY_INFORMATION)
  83                         ? xacl.info.sd_ts->sd->sacl : NULL,
  84                         (security_info & DACL_SECURITY_INFORMATION)
  85                         ? xacl.info.sd_ts->sd->dacl : NULL,
  86                         &sd_size);
  87
  88         TALLOC_FREE(xacl.info.sd);
  89
  90         return (*ppdesc != NULL) ? NT_STATUS_OK : NT_STATUS_NO_MEMORY;
  91 }
  92
  93 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  94                         vfs_handle_struct *handle,
  95                         files_struct *fsp,
  96                         const char *name,
  97                         DATA_BLOB *pblob)
  98 {
  99         size_t size = 1024;
 100         uint8_t *val = NULL;
 101         uint8_t *tmp;
 102         ssize_t sizeret;
 103         int saved_errno = 0;
 104
 105         ZERO_STRUCTP(pblob);
 106
 107   again:
 108
 109         tmp = TALLOC_REALLOC_ARRAY(ctx, val, uint8_t, size);
 110         if (tmp == NULL) {
 111                 TALLOC_FREE(val);
 112                 return NT_STATUS_NO_MEMORY;
 113         }
 114         val = tmp;
 115
 116         become_root();
 117         if (fsp && fsp->fh->fd != -1) {
 118                 sizeret = SMB_VFS_FGETXATTR(fsp, XATTR_NTACL_NAME, val, size);
 119         } else {
 120                 sizeret = SMB_VFS_GETXATTR(handle->conn, name,
 121                                         XATTR_NTACL_NAME, val, size);
 122         }
 123         if (sizeret == -1) {
 124                 saved_errno = errno;
 125         }
 126         unbecome_root();
 127
 128         /* Max ACL size is 65536 bytes. */
 129         if (sizeret == -1) {
 130                 errno = saved_errno;
 131                 if ((errno == ERANGE) && (size != 65536)) {
 132                         /* Too small, try again. */
 133                         size = 65536;
 134                         goto again;
 135                 }
 136
 137                 /* Real error - exit here. */
 138                 TALLOC_FREE(val);
 139                 return map_nt_error_from_unix(errno);
 140         }
 141
 142         pblob->data = val;
 143         pblob->length = sizeret;
 144         return NT_STATUS_OK;
 145 }
 146
 147 static NTSTATUS create_acl_blob(const SEC_DESC *psd, DATA_BLOB *pblob)
 148 {
 149         struct xattr_NTACL xacl;
 150         struct security_descriptor_timestamp sd_ts;
 151         enum ndr_err_code ndr_err;
 152         TALLOC_CTX *ctx = talloc_tos();
 153         struct timespec curr = timespec_current();
 154
 155         ZERO_STRUCT(xacl);
 156         ZERO_STRUCT(sd_ts);
 157
 158         /* Horrid hack as setting an xattr changes the ctime
 159          * on Linux. This gives a race of 1 second during
 160          * which we would not see a POSIX ACL set.
 161          */
 162         curr.tv_sec += 1;
 163
 164         xacl.version = 2;
 165         xacl.info.sd_ts = &sd_ts;
 166         xacl.info.sd_ts->sd = CONST_DISCARD(SEC_DESC *, psd);
 167         unix_timespec_to_nt_time(&xacl.info.sd_ts->last_changed, curr);
 168
 169         DEBUG(10, ("create_acl_blob: timestamp stored as %s\n",
 170                 timestring(ctx, curr.tv_sec) ));
 171
 172         ndr_err = ndr_push_struct_blob(
 173                         pblob, ctx, NULL, &xacl,
 174                         (ndr_push_flags_fn_t)ndr_push_xattr_NTACL);
 175
 176         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 177                 DEBUG(5, ("create_acl_blob: ndr_push_xattr_NTACL failed: %s\n",
 178                         ndr_errstr(ndr_err)));
 179                 return ndr_map_error2ntstatus(ndr_err);;
 180         }
 181
 182         return NT_STATUS_OK;
 183 }
 184
 185 static NTSTATUS store_acl_blob_fsp(files_struct *fsp,
 186                                 DATA_BLOB *pblob)
 187 {
 188         int ret;
 189         int saved_errno = 0;
 190
 191         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 192                         (unsigned int)pblob->length, fsp->fsp_name));
 193
 194         become_root();
 195         if (fsp->fh->fd != -1) {
 196                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 197                         pblob->data, pblob->length, 0);
 198         } else {
 199                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
 200                                 XATTR_NTACL_NAME,
 201                                 pblob->data, pblob->length, 0);
 202         }
 203         if (ret) {
 204                 saved_errno = errno;
 205         }
 206         unbecome_root();
 207         if (ret) {
 208                 errno = saved_errno;
 209                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 210                         "with error %s\n",
 211                         fsp->fsp_name,
 212                         strerror(errno) ));
 213                 return map_nt_error_from_unix(errno);
 214         }
 215         return NT_STATUS_OK;
 216 }
 217
 218 static NTSTATUS store_acl_blob_pathname(connection_struct *conn,
 219                                         const char *fname,
 220                                         DATA_BLOB *pblob)
 221 {
 222         int ret;
 223         int saved_errno = 0;
 224
 225         DEBUG(10,("store_acl_blob_pathname: storing blob "
 226                         "length %u on file %s\n",
 227                         (unsigned int)pblob->length, fname));
 228
 229         become_root();
 230         ret = SMB_VFS_SETXATTR(conn, fname,
 231                                 XATTR_NTACL_NAME,
 232                                 pblob->data, pblob->length, 0);
 233         if (ret) {
 234                 saved_errno = errno;
 235         }
 236         unbecome_root();
 237         if (ret) {
 238                 errno = saved_errno;
 239                 DEBUG(5, ("store_acl_blob_pathname: setting attr failed "
 240                         "for file %s with error %s\n",
 241                         fname,
 242                         strerror(errno) ));
 243                 return map_nt_error_from_unix(errno);
 244         }
 245         return NT_STATUS_OK;
 246 }
 247
 248
 249 static NTSTATUS get_nt_acl_xattr_internal(vfs_handle_struct *handle,
 250                                         files_struct *fsp,
 251                                         const char *name,
 252                                         uint32 security_info,
 253                                         SEC_DESC **ppdesc)
 254 {
 255         TALLOC_CTX *ctx = talloc_tos();
 256         DATA_BLOB blob;
 257         SMB_STRUCT_STAT sbuf;
 258         NTSTATUS status;
 259
 260         if (fsp && name == NULL) {
 261                 name = fsp->fsp_name;
 262         }
 263
 264         DEBUG(10, ("get_nt_acl_xattr_internal: name=%s\n", name));
 265
 266         status = get_acl_blob(ctx, handle, fsp, name, &blob);
 267         if (!NT_STATUS_IS_OK(status)) {
 268                 DEBUG(10, ("get_acl_blob returned %s\n", nt_errstr(status)));
 269                 return status;
 270         }
 271
 272         if (fsp && fsp->fh->fd != -1) {
 273                 if (SMB_VFS_FSTAT(fsp, &sbuf) == -1) {
 274                         return map_nt_error_from_unix(errno);
 275                 }
 276         } else {
 277                 if (SMB_VFS_STAT(handle->conn, name, &sbuf) == -1) {
 278                         return map_nt_error_from_unix(errno);
 279                 }
 280         }
 281
 282         status = parse_acl_blob(&blob, get_ctimespec(&sbuf),
 283                         security_info, ppdesc);
 284         if (!NT_STATUS_IS_OK(status)) {
 285                 DEBUG(10, ("parse_acl_blob returned %s\n",
 286                                 nt_errstr(status)));
 287                 return status;
 288         }
 289
 290         TALLOC_FREE(blob.data);
 291         return status;
 292 }
 293
 294 /*********************************************************************
 295  * Currently this only works for existing files. Need to work on
 296  * inheritance for new files.
 297 *********************************************************************/
 298
 299 static NTSTATUS inherit_new_acl(vfs_handle_struct *handle,
 300                                         const char *fname,
 301                                         files_struct *fsp,
 302                                         bool container)
 303 {
 304         TALLOC_CTX *ctx = talloc_tos();
 305         NTSTATUS status;
 306         SEC_DESC *parent_desc = NULL;
 307         SEC_DESC *psd = NULL;
 308         DATA_BLOB blob;
 309         size_t size;
 310         char *parent_name;
 311
 312         if (!parent_dirname_talloc(ctx,
 313                                 fname,
 314                                 &parent_name,
 315                                 NULL)) {
 316                 return NT_STATUS_NO_MEMORY;
 317         }
 318
 319         DEBUG(10,("inherit_new_acl: check directory %s\n",
 320                         parent_name));
 321
 322         status = get_nt_acl_xattr_internal(handle,
 323                                         NULL,
 324                                         parent_name,
 325                                         DACL_SECURITY_INFORMATION,
 326                                         &parent_desc);
 327         if (!NT_STATUS_IS_OK(status)) {
 328                 DEBUG(10,("inherit_new_acl: directory %s failed "
 329                         "to get acl %s\n",
 330                         parent_name,
 331                         nt_errstr(status) ));
 332                 return status;
 333         }
 334
 335         /* Create an inherited descriptor from the parent. */
 336         status = se_create_child_secdesc(ctx,
 337                                 &psd,
 338                                 &size,
 339                                 parent_desc,
 340                                 &handle->conn->server_info->ptok->user_sids[PRIMARY_USER_SID_INDEX],
 341                                 &handle->conn->server_info->ptok->user_sids[PRIMARY_GROUP_SID_INDEX],
 342                                 container);
 343         if (!NT_STATUS_IS_OK(status)) {
 344                 return status;
 345         }
 346         status = create_acl_blob(psd, &blob);
 347         if (!NT_STATUS_IS_OK(status)) {
 348                 return status;
 349         }
 350         if (fsp) {
 351                 return store_acl_blob_fsp(fsp, &blob);
 352         } else {
 353                 return store_acl_blob_pathname(handle->conn, fname, &blob);
 354         }
 355 }
 356
 357 /*********************************************************************
 358  Check ACL on open. For new files inherit from parent directory.
 359 *********************************************************************/
 360
 361 static int open_acl_xattr(vfs_handle_struct *handle,
 362                                         const char *fname,
 363                                         files_struct *fsp,
 364                                         int flags,
 365                                         mode_t mode)
 366 {
 367         uint32_t access_granted = 0;
 368         SEC_DESC *pdesc = NULL;
 369         bool file_existed = true;
 370         NTSTATUS status = get_nt_acl_xattr_internal(handle,
 371                                         NULL,
 372                                         fname,
 373                                         (OWNER_SECURITY_INFORMATION |
 374                                          GROUP_SECURITY_INFORMATION |
 375                                          DACL_SECURITY_INFORMATION),
 376                                         &pdesc);
 377         if (NT_STATUS_IS_OK(status)) {
 378                 /* See if we can access it. */
 379                 if (!se_access_check(pdesc,
 380                                         handle->conn->server_info->ptok,
 381                                         fsp->access_mask,
 382                                         &access_granted,
 383                                         &status)) {
 384                         errno = map_errno_from_nt_status(status);
 385                         return -1;
 386                 }
 387         } else if (NT_STATUS_EQUAL(status,NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
 388                 file_existed = false;
 389         }
 390
 391         DEBUG(10,("open_acl_xattr: get_nt_acl_attr_internal for "
 392                 "file %s returned %s\n",
 393                 fname,
 394                 nt_errstr(status) ));
 395
 396         fsp->fh->fd = SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode);
 397
 398         if (!file_existed && fsp->fh->fd != -1) {
 399                 /* File was created. Inherit from parent directory. */
 400                 string_set(&fsp->fsp_name, fname);
 401                 inherit_new_acl(handle, fname, fsp, false);
 402         }
 403
 404         return fsp->fh->fd;
 405 }
 406
 407 static int mkdir_acl_xattr(vfs_handle_struct *handle, const char *path, mode_t mode)
 408 {
 409         int ret = SMB_VFS_NEXT_MKDIR(handle, path, mode);
 410
 411         if (ret == -1) {
 412                 return ret;
 413         }
 414         /* New directory - inherit from parent. */
 415         inherit_new_acl(handle, path, NULL, true);
 416         return ret;
 417 }
 418
 419 static NTSTATUS fget_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
 420         uint32 security_info, SEC_DESC **ppdesc)
 421 {
 422         NTSTATUS status = get_nt_acl_xattr_internal(handle, fsp,
 423                                 NULL, security_info, ppdesc);
 424         if (NT_STATUS_IS_OK(status)) {
 425                 if (DEBUGLEVEL >= 10) {
 426                         DEBUG(10,("fget_nt_acl_xattr: returning xattr sd for file %s\n",
 427                                 fsp->fsp_name));
 428                         NDR_PRINT_DEBUG(security_descriptor, *ppdesc);
 429                 }
 430                 return NT_STATUS_OK;
 431         }
 432         return SMB_VFS_NEXT_FGET_NT_ACL(handle, fsp,
 433                         security_info, ppdesc);
 434 }
 435
 436 static NTSTATUS get_nt_acl_xattr(vfs_handle_struct *handle,
 437         const char *name, uint32 security_info, SEC_DESC **ppdesc)
 438 {
 439         NTSTATUS status = get_nt_acl_xattr_internal(handle, NULL,
 440                                 name, security_info, ppdesc);
 441         if (NT_STATUS_IS_OK(status)) {
 442                 if (DEBUGLEVEL >= 10) {
 443                         DEBUG(10,("get_nt_acl_xattr: returning xattr sd for file %s\n",
 444                                 name));
 445                         NDR_PRINT_DEBUG(security_descriptor, *ppdesc);
 446                 }
 447                 return NT_STATUS_OK;
 448         }
 449         return SMB_VFS_NEXT_GET_NT_ACL(handle, name,
 450                         security_info, ppdesc);
 451 }
 452
 453 static NTSTATUS fset_nt_acl_xattr(vfs_handle_struct *handle, files_struct *fsp,
 454         uint32 security_info_sent, const SEC_DESC *psd)
 455 {
 456         NTSTATUS status;
 457         DATA_BLOB blob;
 458
 459         if (DEBUGLEVEL >= 10) {
 460                 DEBUG(10,("fset_nt_acl_xattr: incoming sd for file %s\n",
 461                         fsp->fsp_name));
 462                 NDR_PRINT_DEBUG(security_descriptor,
 463                         CONST_DISCARD(SEC_DESC *,psd));
 464         }
 465
 466         status = SMB_VFS_NEXT_FSET_NT_ACL(handle, fsp, security_info_sent, psd);
 467         if (!NT_STATUS_IS_OK(status)) {
 468                 return status;
 469         }
 470
 471         /* Ensure owner and group are set. */
 472         if (!psd->owner_sid || !psd->group_sid) {
 473                 int ret;
 474                 SMB_STRUCT_STAT sbuf;
 475                 DOM_SID owner_sid, group_sid;
 476                 SEC_DESC *nc_psd = dup_sec_desc(talloc_tos(), psd);
 477
 478                 if (!nc_psd) {
 479                         return NT_STATUS_OK;
 480                 }
 481                 if (fsp->is_directory || fsp->fh->fd == -1) {
 482                         ret = SMB_VFS_STAT(fsp->conn,fsp->fsp_name, &sbuf);
 483                 } else {
 484                         ret = SMB_VFS_FSTAT(fsp, &sbuf);
 485                 }
 486                 if (ret == -1) {
 487                         /* Lower level acl set succeeded,
 488                          * so still return OK. */
 489                         return NT_STATUS_OK;
 490                 }
 491                 create_file_sids(&sbuf, &owner_sid, &group_sid);
 492                 /* This is safe as nc_psd is discarded at fn exit. */
 493                 nc_psd->owner_sid = &owner_sid;
 494                 nc_psd->group_sid = &group_sid;
 495                 security_info_sent |= (OWNER_SECURITY_INFORMATION|GROUP_SECURITY_INFORMATION);
 496                 psd = nc_psd;
 497         }
 498
 499         if ((security_info_sent & DACL_SECURITY_INFORMATION) &&
 500                         psd->dacl != NULL &&
 501                         (psd->type & (SE_DESC_DACL_AUTO_INHERITED|
 502                                 SE_DESC_DACL_AUTO_INHERIT_REQ))==
 503                                 (SE_DESC_DACL_AUTO_INHERITED|
 504                                 SE_DESC_DACL_AUTO_INHERIT_REQ) ) {
 505                 SEC_DESC *new_psd = NULL;
 506                 status = append_parent_acl(fsp, psd, &new_psd);
 507                 if (!NT_STATUS_IS_OK(status)) {
 508                         /* Lower level acl set succeeded,
 509                          * so still return OK. */
 510                         return NT_STATUS_OK;
 511                 }
 512                 psd = new_psd;
 513         }
 514
 515         if (DEBUGLEVEL >= 10) {
 516                 DEBUG(10,("fset_nt_acl_xattr: storing xattr sd for file %s\n",
 517                         fsp->fsp_name));
 518                 NDR_PRINT_DEBUG(security_descriptor,
 519                         CONST_DISCARD(SEC_DESC *,psd));
 520         }
 521         create_acl_blob(psd, &blob);
 522         store_acl_blob_fsp(fsp, &blob);
 523
 524         return NT_STATUS_OK;
 525 }
 526
 527 /* VFS operations structure */
 528
 529 static vfs_op_tuple skel_op_tuples[] =
 530 {
 531         {SMB_VFS_OP(mkdir_acl_xattr), SMB_VFS_OP_MKDIR, SMB_VFS_LAYER_TRANSPARENT},
 532         {SMB_VFS_OP(open_acl_xattr),  SMB_VFS_OP_OPEN,  SMB_VFS_LAYER_TRANSPARENT},
 533
 534         /* NT File ACL operations */
 535
 536         {SMB_VFS_OP(fget_nt_acl_xattr),SMB_VFS_OP_FGET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
 537         {SMB_VFS_OP(get_nt_acl_xattr), SMB_VFS_OP_GET_NT_ACL, SMB_VFS_LAYER_TRANSPARENT},
 538         {SMB_VFS_OP(fset_nt_acl_xattr),SMB_VFS_OP_FSET_NT_ACL,SMB_VFS_LAYER_TRANSPARENT},
 539
 540         {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP}
 541 };
 542
 543 NTSTATUS vfs_acl_xattr_init(void)
 544 {
 545         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr", skel_op_tuples);
 546 }