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 #include "includes.h"
  22 #include "smbd/smbd.h"
  23 #include "system/filesys.h"
  24 #include "librpc/gen_ndr/xattr.h"
  25 #include "auth.h"
  26 #include "vfs_acl_common.h"
  27
  28 /* Pull in the common functions. */
  29 #define ACL_MODULE_NAME "acl_xattr"
  30
  31 #undef DBGC_CLASS
  32 #define DBGC_CLASS DBGC_VFS
  33
  34 /*******************************************************************
  35  Pull a security descriptor into a DATA_BLOB from a xattr.
  36 *******************************************************************/
  37
  38 static ssize_t getxattr_do(vfs_handle_struct *handle,
  39                            files_struct *fsp,
  40                            const struct smb_filename *smb_fname,
  41                            const char *xattr_name,
  42                            uint8_t *val,
  43                            size_t size)
  44 {
  45         ssize_t sizeret;
  46         int saved_errno = 0;
  47
  48         become_root();
  49         if (fsp && fsp->fh->fd != -1) {
  50                 sizeret = SMB_VFS_FGETXATTR(fsp, xattr_name, val, size);
  51         } else {
  52                 sizeret = SMB_VFS_GETXATTR(handle->conn, smb_fname,
  53                                            XATTR_NTACL_NAME, val, size);
  54         }
  55         if (sizeret == -1) {
  56                 saved_errno = errno;
  57         }
  58         unbecome_root();
  59
  60         if (saved_errno != 0) {
  61                 errno = saved_errno;
  62         }
  63
  64         return sizeret;
  65 }
  66
  67 static NTSTATUS fget_acl_blob(TALLOC_CTX *ctx,
  68                         vfs_handle_struct *handle,
  69                         files_struct *fsp,
  70                         DATA_BLOB *pblob)
  71 {
  72         size_t size = 4096;
  73         uint8_t *val = NULL;
  74         uint8_t *tmp;
  75         ssize_t sizeret;
  76
  77         ZERO_STRUCTP(pblob);
  78
  79   again:
  80
  81         tmp = talloc_realloc(ctx, val, uint8_t, size);
  82         if (tmp == NULL) {
  83                 TALLOC_FREE(val);
  84                 return NT_STATUS_NO_MEMORY;
  85         }
  86         val = tmp;
  87
  88         sizeret =
  89             getxattr_do(handle, fsp, NULL, XATTR_NTACL_NAME, val, size);
  90
  91         if (sizeret >= 0) {
  92                 pblob->data = val;
  93                 pblob->length = sizeret;
  94                 return NT_STATUS_OK;
  95         }
  96
  97         if (errno != ERANGE) {
  98                 goto err;
  99         }
 100
 101         /* Too small, try again. */
 102         sizeret =
 103             getxattr_do(handle, fsp, NULL, XATTR_NTACL_NAME, NULL, 0);
 104         if (sizeret < 0) {
 105                 goto err;
 106         }
 107
 108         if (size < sizeret) {
 109                 size = sizeret;
 110         }
 111
 112         if (size > 65536) {
 113                 /* Max ACL size is 65536 bytes. */
 114                 errno = ERANGE;
 115                 goto err;
 116         }
 117
 118         goto again;
 119   err:
 120         /* Real error - exit here. */
 121         TALLOC_FREE(val);
 122         return map_nt_error_from_unix(errno);
 123 }
 124
 125 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
 126                         vfs_handle_struct *handle,
 127                         files_struct *fsp,
 128                         const struct smb_filename *smb_fname,
 129                         DATA_BLOB *pblob)
 130 {
 131         size_t size = 4096;
 132         uint8_t *val = NULL;
 133         uint8_t *tmp;
 134         ssize_t sizeret;
 135
 136         ZERO_STRUCTP(pblob);
 137
 138   again:
 139
 140         tmp = talloc_realloc(ctx, val, uint8_t, size);
 141         if (tmp == NULL) {
 142                 TALLOC_FREE(val);
 143                 return NT_STATUS_NO_MEMORY;
 144         }
 145         val = tmp;
 146
 147         sizeret =
 148             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, val, size);
 149
 150         if (sizeret >= 0) {
 151                 pblob->data = val;
 152                 pblob->length = sizeret;
 153                 return NT_STATUS_OK;
 154         }
 155
 156         if (errno != ERANGE) {
 157                 goto err;
 158         }
 159
 160         /* Too small, try again. */
 161         sizeret =
 162             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, NULL, 0);
 163         if (sizeret < 0) {
 164                 goto err;
 165         }
 166
 167         if (size < sizeret) {
 168                 size = sizeret;
 169         }
 170
 171         if (size > 65536) {
 172                 /* Max ACL size is 65536 bytes. */
 173                 errno = ERANGE;
 174                 goto err;
 175         }
 176
 177         goto again;
 178   err:
 179         /* Real error - exit here. */
 180         TALLOC_FREE(val);
 181         return map_nt_error_from_unix(errno);
 182 }
 183
 184 /*******************************************************************
 185  Store a DATA_BLOB into an xattr given an fsp pointer.
 186 *******************************************************************/
 187
 188 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
 189                                 files_struct *fsp,
 190                                 DATA_BLOB *pblob)
 191 {
 192         int ret;
 193         int saved_errno = 0;
 194
 195         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 196                   (unsigned int)pblob->length, fsp_str_dbg(fsp)));
 197
 198         become_root();
 199         if (fsp->fh->fd != -1) {
 200                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 201                         pblob->data, pblob->length, 0);
 202         } else {
 203                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
 204                                 XATTR_NTACL_NAME,
 205                                 pblob->data, pblob->length, 0);
 206         }
 207         if (ret) {
 208                 saved_errno = errno;
 209         }
 210         unbecome_root();
 211         if (ret) {
 212                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 213                         "with error %s\n",
 214                         fsp_str_dbg(fsp),
 215                         strerror(saved_errno) ));
 216                 errno = saved_errno;
 217                 return map_nt_error_from_unix(saved_errno);
 218         }
 219         return NT_STATUS_OK;
 220 }
 221
 222 /*********************************************************************
 223  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 224 *********************************************************************/
 225
 226 static int sys_acl_set_file_xattr(vfs_handle_struct *handle,
 227                                 const struct smb_filename *smb_fname,
 228                                 SMB_ACL_TYPE_T type,
 229                                 SMB_ACL_T theacl)
 230 {
 231         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FILE(handle,
 232                                                 smb_fname,
 233                                                 type,
 234                                                 theacl);
 235         if (ret == -1) {
 236                 return -1;
 237         }
 238
 239         become_root();
 240         SMB_VFS_REMOVEXATTR(handle->conn, smb_fname,
 241                         XATTR_NTACL_NAME);
 242         unbecome_root();
 243
 244         return ret;
 245 }
 246
 247 /*********************************************************************
 248  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 249 *********************************************************************/
 250
 251 static int sys_acl_set_fd_xattr(vfs_handle_struct *handle,
 252                             files_struct *fsp,
 253                             SMB_ACL_T theacl)
 254 {
 255         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FD(handle,
 256                                                 fsp,
 257                                                 theacl);
 258         if (ret == -1) {
 259                 return -1;
 260         }
 261
 262         become_root();
 263         SMB_VFS_FREMOVEXATTR(fsp, XATTR_NTACL_NAME);
 264         unbecome_root();
 265
 266         return ret;
 267 }
 268
 269 static int connect_acl_xattr(struct vfs_handle_struct *handle,
 270                                 const char *service,
 271                                 const char *user)
 272 {
 273         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 274         bool ok;
 275         struct acl_common_config *config = NULL;
 276
 277         if (ret < 0) {
 278                 return ret;
 279         }
 280
 281         ok = init_acl_common_config(handle, ACL_MODULE_NAME);
 282         if (!ok) {
 283                 DBG_ERR("init_acl_common_config failed\n");
 284                 return -1;
 285         }
 286
 287         /* Ensure we have the parameters correct if we're
 288          * using this module. */
 289         DEBUG(2,("connect_acl_xattr: setting 'inherit acls = true' "
 290                 "'dos filemode = true' and "
 291                 "'force unknown acl user = true' for service %s\n",
 292                 service ));
 293
 294         lp_do_parameter(SNUM(handle->conn), "inherit acls", "true");
 295         lp_do_parameter(SNUM(handle->conn), "dos filemode", "true");
 296         lp_do_parameter(SNUM(handle->conn), "force unknown acl user", "true");
 297
 298         SMB_VFS_HANDLE_GET_DATA(handle, config,
 299                                 struct acl_common_config,
 300                                 return -1);
 301
 302         if (config->ignore_system_acls) {
 303                 mode_t create_mask = lp_create_mask(SNUM(handle->conn));
 304                 char *create_mask_str = NULL;
 305
 306                 if ((create_mask & 0666) != 0666) {
 307                         create_mask |= 0666;
 308                         create_mask_str = talloc_asprintf(handle, "0%o",
 309                                                           create_mask);
 310                         if (create_mask_str == NULL) {
 311                                 DBG_ERR("talloc_asprintf failed\n");
 312                                 return -1;
 313                         }
 314
 315                         DBG_NOTICE("setting 'create mask = %s'\n", create_mask_str);
 316
 317                         lp_do_parameter (SNUM(handle->conn),
 318                                         "create mask", create_mask_str);
 319
 320                         TALLOC_FREE(create_mask_str);
 321                 }
 322
 323                 DBG_NOTICE("setting 'directory mask = 0777', "
 324                            "'store dos attributes = yes' and all "
 325                            "'map ...' options to 'no'\n");
 326
 327                 lp_do_parameter(SNUM(handle->conn), "directory mask", "0777");
 328                 lp_do_parameter(SNUM(handle->conn), "map archive", "no");
 329                 lp_do_parameter(SNUM(handle->conn), "map hidden", "no");
 330                 lp_do_parameter(SNUM(handle->conn), "map readonly", "no");
 331                 lp_do_parameter(SNUM(handle->conn), "map system", "no");
 332                 lp_do_parameter(SNUM(handle->conn), "store dos attributes",
 333                                 "yes");
 334         }
 335
 336         return 0;
 337 }
 338
 339 static int acl_xattr_unlinkat(vfs_handle_struct *handle,
 340                         struct files_struct *dirfsp,
 341                         const struct smb_filename *smb_fname,
 342                         int flags)
 343 {
 344         int ret;
 345
 346         if (flags & AT_REMOVEDIR) {
 347                 ret = rmdir_acl_common(handle,
 348                                 dirfsp,
 349                                 smb_fname);
 350         } else {
 351                 ret = unlink_acl_common(handle,
 352                                 dirfsp,
 353                                 smb_fname,
 354                                 flags);
 355         }
 356         return ret;
 357 }
 358
 359 static NTSTATUS acl_xattr_fget_nt_acl(vfs_handle_struct *handle,
 360                                       files_struct *fsp,
 361                                       uint32_t security_info,
 362                                       TALLOC_CTX *mem_ctx,
 363                                       struct security_descriptor **ppdesc)
 364 {
 365         NTSTATUS status;
 366         status = get_nt_acl_common(get_acl_blob, handle, fsp, NULL,
 367                                    security_info, mem_ctx, ppdesc);
 368         return status;
 369 }
 370
 371 static NTSTATUS acl_xattr_get_nt_acl(vfs_handle_struct *handle,
 372                                      const struct smb_filename *smb_fname,
 373                                      uint32_t security_info,
 374                                      TALLOC_CTX *mem_ctx,
 375                                      struct security_descriptor **ppdesc)
 376 {
 377         NTSTATUS status;
 378         status = get_nt_acl_common(get_acl_blob, handle, NULL, smb_fname,
 379                                    security_info, mem_ctx, ppdesc);
 380         return status;
 381 }
 382
 383 static NTSTATUS acl_xattr_fset_nt_acl(vfs_handle_struct *handle,
 384                                       files_struct *fsp,
 385                                       uint32_t security_info_sent,
 386                                       const struct security_descriptor *psd)
 387 {
 388         NTSTATUS status;
 389         status = fset_nt_acl_common(fget_acl_blob, store_acl_blob_fsp,
 390                                     ACL_MODULE_NAME,
 391                                     handle, fsp, security_info_sent, psd);
 392         return status;
 393 }
 394
 395 static struct vfs_fn_pointers vfs_acl_xattr_fns = {
 396         .connect_fn = connect_acl_xattr,
 397         .unlinkat_fn = acl_xattr_unlinkat,
 398         .chmod_fn = chmod_acl_module_common,
 399         .fchmod_fn = fchmod_acl_module_common,
 400         .fget_nt_acl_fn = acl_xattr_fget_nt_acl,
 401         .get_nt_acl_fn = acl_xattr_get_nt_acl,
 402         .fset_nt_acl_fn = acl_xattr_fset_nt_acl,
 403         .sys_acl_set_file_fn = sys_acl_set_file_xattr,
 404         .sys_acl_set_fd_fn = sys_acl_set_fd_xattr
 405 };
 406
 407 static_decl_vfs;
 408 NTSTATUS vfs_acl_xattr_init(TALLOC_CTX *ctx)
 409 {
 410         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr",
 411                                 &vfs_acl_xattr_fns);
 412 }