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 "auth.h"
  25 #include "vfs_acl_common.h"
  26
  27 /* Pull in the common functions. */
  28 #define ACL_MODULE_NAME "acl_xattr"
  29
  30 #undef DBGC_CLASS
  31 #define DBGC_CLASS DBGC_VFS
  32
  33 /*******************************************************************
  34  Pull a security descriptor into a DATA_BLOB from a xattr.
  35 *******************************************************************/
  36
  37 static ssize_t getxattr_do(vfs_handle_struct *handle,
  38                            files_struct *fsp,
  39                            const struct smb_filename *smb_fname,
  40                            const char *xattr_name,
  41                            uint8_t *val,
  42                            size_t size)
  43 {
  44         ssize_t sizeret;
  45         int saved_errno = 0;
  46
  47         become_root();
  48         if (fsp && fsp->fh->fd != -1) {
  49                 sizeret = SMB_VFS_FGETXATTR(fsp, xattr_name, val, size);
  50         } else {
  51                 sizeret = SMB_VFS_GETXATTR(handle->conn, smb_fname,
  52                                            XATTR_NTACL_NAME, val, size);
  53         }
  54         if (sizeret == -1) {
  55                 saved_errno = errno;
  56         }
  57         unbecome_root();
  58
  59         if (saved_errno != 0) {
  60                 errno = saved_errno;
  61         }
  62
  63         return sizeret;
  64 }
  65
  66 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  67                         vfs_handle_struct *handle,
  68                         files_struct *fsp,
  69                         const struct smb_filename *smb_fname,
  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, smb_fname, 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, smb_fname, 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 /*******************************************************************
 126  Store a DATA_BLOB into an xattr given an fsp pointer.
 127 *******************************************************************/
 128
 129 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
 130                                 files_struct *fsp,
 131                                 DATA_BLOB *pblob)
 132 {
 133         int ret;
 134         int saved_errno = 0;
 135
 136         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 137                   (unsigned int)pblob->length, fsp_str_dbg(fsp)));
 138
 139         become_root();
 140         if (fsp->fh->fd != -1) {
 141                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 142                         pblob->data, pblob->length, 0);
 143         } else {
 144                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
 145                                 XATTR_NTACL_NAME,
 146                                 pblob->data, pblob->length, 0);
 147         }
 148         if (ret) {
 149                 saved_errno = errno;
 150         }
 151         unbecome_root();
 152         if (ret) {
 153                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 154                         "with error %s\n",
 155                         fsp_str_dbg(fsp),
 156                         strerror(saved_errno) ));
 157                 errno = saved_errno;
 158                 return map_nt_error_from_unix(saved_errno);
 159         }
 160         return NT_STATUS_OK;
 161 }
 162
 163 /*********************************************************************
 164  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 165 *********************************************************************/
 166
 167 static int sys_acl_set_file_xattr(vfs_handle_struct *handle,
 168                                 const struct smb_filename *smb_fname,
 169                                 SMB_ACL_TYPE_T type,
 170                                 SMB_ACL_T theacl)
 171 {
 172         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FILE(handle,
 173                                                 smb_fname,
 174                                                 type,
 175                                                 theacl);
 176         if (ret == -1) {
 177                 return -1;
 178         }
 179
 180         become_root();
 181         SMB_VFS_REMOVEXATTR(handle->conn, smb_fname,
 182                         XATTR_NTACL_NAME);
 183         unbecome_root();
 184
 185         return ret;
 186 }
 187
 188 /*********************************************************************
 189  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 190 *********************************************************************/
 191
 192 static int sys_acl_set_fd_xattr(vfs_handle_struct *handle,
 193                             files_struct *fsp,
 194                             SMB_ACL_T theacl)
 195 {
 196         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FD(handle,
 197                                                 fsp,
 198                                                 theacl);
 199         if (ret == -1) {
 200                 return -1;
 201         }
 202
 203         become_root();
 204         SMB_VFS_FREMOVEXATTR(fsp, XATTR_NTACL_NAME);
 205         unbecome_root();
 206
 207         return ret;
 208 }
 209
 210 static int connect_acl_xattr(struct vfs_handle_struct *handle,
 211                                 const char *service,
 212                                 const char *user)
 213 {
 214         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 215         bool ok;
 216         struct acl_common_config *config = NULL;
 217
 218         if (ret < 0) {
 219                 return ret;
 220         }
 221
 222         ok = init_acl_common_config(handle, ACL_MODULE_NAME);
 223         if (!ok) {
 224                 DBG_ERR("init_acl_common_config failed\n");
 225                 return -1;
 226         }
 227
 228         /* Ensure we have the parameters correct if we're
 229          * using this module. */
 230         DEBUG(2,("connect_acl_xattr: setting 'inherit acls = true' "
 231                 "'dos filemode = true' and "
 232                 "'force unknown acl user = true' for service %s\n",
 233                 service ));
 234
 235         lp_do_parameter(SNUM(handle->conn), "inherit acls", "true");
 236         lp_do_parameter(SNUM(handle->conn), "dos filemode", "true");
 237         lp_do_parameter(SNUM(handle->conn), "force unknown acl user", "true");
 238
 239         SMB_VFS_HANDLE_GET_DATA(handle, config,
 240                                 struct acl_common_config,
 241                                 return -1);
 242
 243         if (config->ignore_system_acls) {
 244                 mode_t create_mask = lp_create_mask(SNUM(handle->conn));
 245                 char *create_mask_str = NULL;
 246
 247                 if ((create_mask & 0666) != 0666) {
 248                         create_mask |= 0666;
 249                         create_mask_str = talloc_asprintf(handle, "0%o",
 250                                                           create_mask);
 251                         if (create_mask_str == NULL) {
 252                                 DBG_ERR("talloc_asprintf failed\n");
 253                                 return -1;
 254                         }
 255
 256                         DBG_NOTICE("setting 'create mask = %s'\n", create_mask_str);
 257
 258                         lp_do_parameter (SNUM(handle->conn),
 259                                         "create mask", create_mask_str);
 260
 261                         TALLOC_FREE(create_mask_str);
 262                 }
 263
 264                 DBG_NOTICE("setting 'directory mask = 0777', "
 265                            "'store dos attributes = yes' and all "
 266                            "'map ...' options to 'no'\n");
 267
 268                 lp_do_parameter(SNUM(handle->conn), "directory mask", "0777");
 269                 lp_do_parameter(SNUM(handle->conn), "map archive", "no");
 270                 lp_do_parameter(SNUM(handle->conn), "map hidden", "no");
 271                 lp_do_parameter(SNUM(handle->conn), "map readonly", "no");
 272                 lp_do_parameter(SNUM(handle->conn), "map system", "no");
 273                 lp_do_parameter(SNUM(handle->conn), "store dos attributes",
 274                                 "yes");
 275         }
 276
 277         return 0;
 278 }
 279
 280 static NTSTATUS acl_xattr_fget_nt_acl(vfs_handle_struct *handle,
 281                                       files_struct *fsp,
 282                                       uint32_t security_info,
 283                                       TALLOC_CTX *mem_ctx,
 284                                       struct security_descriptor **ppdesc)
 285 {
 286         NTSTATUS status;
 287         status = get_nt_acl_common(get_acl_blob, handle, fsp, NULL,
 288                                    security_info, mem_ctx, ppdesc);
 289         return status;
 290 }
 291
 292 static NTSTATUS acl_xattr_get_nt_acl(vfs_handle_struct *handle,
 293                                      const struct smb_filename *smb_fname,
 294                                      uint32_t security_info,
 295                                      TALLOC_CTX *mem_ctx,
 296                                      struct security_descriptor **ppdesc)
 297 {
 298         NTSTATUS status;
 299         status = get_nt_acl_common(get_acl_blob, handle, NULL, smb_fname,
 300                                    security_info, mem_ctx, ppdesc);
 301         return status;
 302 }
 303
 304 static NTSTATUS acl_xattr_fset_nt_acl(vfs_handle_struct *handle,
 305                                       files_struct *fsp,
 306                                       uint32_t security_info_sent,
 307                                       const struct security_descriptor *psd)
 308 {
 309         NTSTATUS status;
 310         status = fset_nt_acl_common(get_acl_blob, store_acl_blob_fsp,
 311                                     ACL_MODULE_NAME,
 312                                     handle, fsp, security_info_sent, psd);
 313         return status;
 314 }
 315
 316 static struct vfs_fn_pointers vfs_acl_xattr_fns = {
 317         .connect_fn = connect_acl_xattr,
 318         .rmdir_fn = rmdir_acl_common,
 319         .unlink_fn = unlink_acl_common,
 320         .chmod_fn = chmod_acl_module_common,
 321         .fchmod_fn = fchmod_acl_module_common,
 322         .fget_nt_acl_fn = acl_xattr_fget_nt_acl,
 323         .get_nt_acl_fn = acl_xattr_get_nt_acl,
 324         .fset_nt_acl_fn = acl_xattr_fset_nt_acl,
 325         .sys_acl_set_file_fn = sys_acl_set_file_xattr,
 326         .sys_acl_set_fd_fn = sys_acl_set_fd_xattr
 327 };
 328
 329 static_decl_vfs;
 330 NTSTATUS vfs_acl_xattr_init(TALLOC_CTX *ctx)
 331 {
 332         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr",
 333                                 &vfs_acl_xattr_fns);
 334 }