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 "librpc/gen_ndr/xattr.h"
  24 #include "../lib/crypto/sha256.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 get_acl_blob(TALLOC_CTX *ctx,
  68                         vfs_handle_struct *handle,
  69                         files_struct *fsp,
  70                         const struct smb_filename *smb_fname,
  71                         DATA_BLOB *pblob)
  72 {
  73         size_t size = 4096;
  74         uint8_t *val = NULL;
  75         uint8_t *tmp;
  76         ssize_t sizeret;
  77
  78         ZERO_STRUCTP(pblob);
  79
  80   again:
  81
  82         tmp = talloc_realloc(ctx, val, uint8_t, size);
  83         if (tmp == NULL) {
  84                 TALLOC_FREE(val);
  85                 return NT_STATUS_NO_MEMORY;
  86         }
  87         val = tmp;
  88
  89         sizeret =
  90             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, val, size);
  91
  92         if (sizeret >= 0) {
  93                 pblob->data = val;
  94                 pblob->length = sizeret;
  95                 return NT_STATUS_OK;
  96         }
  97
  98         if (errno != ERANGE) {
  99                 goto err;
 100         }
 101
 102         /* Too small, try again. */
 103         sizeret =
 104             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, NULL, 0);
 105         if (sizeret < 0) {
 106                 goto err;
 107         }
 108
 109         if (size < sizeret) {
 110                 size = sizeret;
 111         }
 112
 113         if (size > 65536) {
 114                 /* Max ACL size is 65536 bytes. */
 115                 errno = ERANGE;
 116                 goto err;
 117         }
 118
 119         goto again;
 120   err:
 121         /* Real error - exit here. */
 122         TALLOC_FREE(val);
 123         return map_nt_error_from_unix(errno);
 124 }
 125
 126 /*******************************************************************
 127  Store a DATA_BLOB into an xattr given an fsp pointer.
 128 *******************************************************************/
 129
 130 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
 131                                 files_struct *fsp,
 132                                 DATA_BLOB *pblob)
 133 {
 134         int ret;
 135         int saved_errno = 0;
 136
 137         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 138                   (unsigned int)pblob->length, fsp_str_dbg(fsp)));
 139
 140         become_root();
 141         if (fsp->fh->fd != -1) {
 142                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 143                         pblob->data, pblob->length, 0);
 144         } else {
 145                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
 146                                 XATTR_NTACL_NAME,
 147                                 pblob->data, pblob->length, 0);
 148         }
 149         if (ret) {
 150                 saved_errno = errno;
 151         }
 152         unbecome_root();
 153         if (ret) {
 154                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 155                         "with error %s\n",
 156                         fsp_str_dbg(fsp),
 157                         strerror(saved_errno) ));
 158                 errno = saved_errno;
 159                 return map_nt_error_from_unix(saved_errno);
 160         }
 161         return NT_STATUS_OK;
 162 }
 163
 164 /*********************************************************************
 165  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 166 *********************************************************************/
 167
 168 static int sys_acl_set_file_xattr(vfs_handle_struct *handle,
 169                                 const struct smb_filename *smb_fname,
 170                                 SMB_ACL_TYPE_T type,
 171                                 SMB_ACL_T theacl)
 172 {
 173         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FILE(handle,
 174                                                 smb_fname,
 175                                                 type,
 176                                                 theacl);
 177         if (ret == -1) {
 178                 return -1;
 179         }
 180
 181         become_root();
 182         SMB_VFS_REMOVEXATTR(handle->conn, smb_fname,
 183                         XATTR_NTACL_NAME);
 184         unbecome_root();
 185
 186         return ret;
 187 }
 188
 189 /*********************************************************************
 190  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 191 *********************************************************************/
 192
 193 static int sys_acl_set_fd_xattr(vfs_handle_struct *handle,
 194                             files_struct *fsp,
 195                             SMB_ACL_T theacl)
 196 {
 197         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FD(handle,
 198                                                 fsp,
 199                                                 theacl);
 200         if (ret == -1) {
 201                 return -1;
 202         }
 203
 204         become_root();
 205         SMB_VFS_FREMOVEXATTR(fsp, XATTR_NTACL_NAME);
 206         unbecome_root();
 207
 208         return ret;
 209 }
 210
 211 static int connect_acl_xattr(struct vfs_handle_struct *handle,
 212                                 const char *service,
 213                                 const char *user)
 214 {
 215         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 216         bool ok;
 217         struct acl_common_config *config = NULL;
 218
 219         if (ret < 0) {
 220                 return ret;
 221         }
 222
 223         ok = init_acl_common_config(handle, ACL_MODULE_NAME);
 224         if (!ok) {
 225                 DBG_ERR("init_acl_common_config failed\n");
 226                 return -1;
 227         }
 228
 229         /* Ensure we have the parameters correct if we're
 230          * using this module. */
 231         DEBUG(2,("connect_acl_xattr: setting 'inherit acls = true' "
 232                 "'dos filemode = true' and "
 233                 "'force unknown acl user = true' for service %s\n",
 234                 service ));
 235
 236         lp_do_parameter(SNUM(handle->conn), "inherit acls", "true");
 237         lp_do_parameter(SNUM(handle->conn), "dos filemode", "true");
 238         lp_do_parameter(SNUM(handle->conn), "force unknown acl user", "true");
 239
 240         SMB_VFS_HANDLE_GET_DATA(handle, config,
 241                                 struct acl_common_config,
 242                                 return -1);
 243
 244         if (config->ignore_system_acls) {
 245                 mode_t create_mask = lp_create_mask(SNUM(handle->conn));
 246                 char *create_mask_str = NULL;
 247
 248                 if ((create_mask & 0666) != 0666) {
 249                         create_mask |= 0666;
 250                         create_mask_str = talloc_asprintf(handle, "0%o",
 251                                                           create_mask);
 252                         if (create_mask_str == NULL) {
 253                                 DBG_ERR("talloc_asprintf failed\n");
 254                                 return -1;
 255                         }
 256
 257                         DBG_NOTICE("setting 'create mask = %s'\n", create_mask_str);
 258
 259                         lp_do_parameter (SNUM(handle->conn),
 260                                         "create mask", create_mask_str);
 261
 262                         TALLOC_FREE(create_mask_str);
 263                 }
 264
 265                 DBG_NOTICE("setting 'directory mask = 0777', "
 266                            "'store dos attributes = yes' and all "
 267                            "'map ...' options to 'no'\n");
 268
 269                 lp_do_parameter(SNUM(handle->conn), "directory mask", "0777");
 270                 lp_do_parameter(SNUM(handle->conn), "map archive", "no");
 271                 lp_do_parameter(SNUM(handle->conn), "map hidden", "no");
 272                 lp_do_parameter(SNUM(handle->conn), "map readonly", "no");
 273                 lp_do_parameter(SNUM(handle->conn), "map system", "no");
 274                 lp_do_parameter(SNUM(handle->conn), "store dos attributes",
 275                                 "yes");
 276         }
 277
 278         return 0;
 279 }
 280
 281 static NTSTATUS acl_xattr_fget_nt_acl(vfs_handle_struct *handle,
 282                                       files_struct *fsp,
 283                                       uint32_t security_info,
 284                                       TALLOC_CTX *mem_ctx,
 285                                       struct security_descriptor **ppdesc)
 286 {
 287         NTSTATUS status;
 288         status = get_nt_acl_common(get_acl_blob, handle, fsp, NULL,
 289                                    security_info, mem_ctx, ppdesc);
 290         return status;
 291 }
 292
 293 static NTSTATUS acl_xattr_get_nt_acl(vfs_handle_struct *handle,
 294                                      const struct smb_filename *smb_fname,
 295                                      uint32_t security_info,
 296                                      TALLOC_CTX *mem_ctx,
 297                                      struct security_descriptor **ppdesc)
 298 {
 299         NTSTATUS status;
 300         status = get_nt_acl_common(get_acl_blob, handle, NULL, smb_fname,
 301                                    security_info, mem_ctx, ppdesc);
 302         return status;
 303 }
 304
 305 static NTSTATUS acl_xattr_fset_nt_acl(vfs_handle_struct *handle,
 306                                       files_struct *fsp,
 307                                       uint32_t security_info_sent,
 308                                       const struct security_descriptor *psd)
 309 {
 310         NTSTATUS status;
 311         status = fset_nt_acl_common(get_acl_blob, store_acl_blob_fsp,
 312                                     ACL_MODULE_NAME,
 313                                     handle, fsp, security_info_sent, psd);
 314         return status;
 315 }
 316
 317 static struct vfs_fn_pointers vfs_acl_xattr_fns = {
 318         .connect_fn = connect_acl_xattr,
 319         .rmdir_fn = rmdir_acl_common,
 320         .unlink_fn = unlink_acl_common,
 321         .chmod_fn = chmod_acl_module_common,
 322         .fchmod_fn = fchmod_acl_module_common,
 323         .fget_nt_acl_fn = acl_xattr_fget_nt_acl,
 324         .get_nt_acl_fn = acl_xattr_get_nt_acl,
 325         .fset_nt_acl_fn = acl_xattr_fset_nt_acl,
 326         .chmod_acl_fn = chmod_acl_acl_module_common,
 327         .fchmod_acl_fn = fchmod_acl_acl_module_common,
 328         .sys_acl_set_file_fn = sys_acl_set_file_xattr,
 329         .sys_acl_set_fd_fn = sys_acl_set_fd_xattr
 330 };
 331
 332 static_decl_vfs;
 333 NTSTATUS vfs_acl_xattr_init(TALLOC_CTX *ctx)
 334 {
 335         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr",
 336                                 &vfs_acl_xattr_fns);
 337 }