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 "librpc/gen_ndr/ndr_xattr.h"
  25 #include "../lib/crypto/sha256.h"
  26 #include "auth.h"
  27
  28 #undef DBGC_CLASS
  29 #define DBGC_CLASS DBGC_VFS
  30
  31 /* Pull in the common functions. */
  32 #define ACL_MODULE_NAME "acl_xattr"
  33
  34 #include "modules/vfs_acl_common.c"
  35
  36 /*******************************************************************
  37  Pull a security descriptor into a DATA_BLOB from a xattr.
  38 *******************************************************************/
  39
  40 static ssize_t getxattr_do(vfs_handle_struct *handle,
  41                            files_struct *fsp,
  42                            const struct smb_filename *smb_fname,
  43                            const char *xattr_name,
  44                            uint8_t *val,
  45                            size_t size)
  46 {
  47         ssize_t sizeret;
  48         int saved_errno = 0;
  49
  50         become_root();
  51         if (fsp && fsp->fh->fd != -1) {
  52                 sizeret = SMB_VFS_FGETXATTR(fsp, xattr_name, val, size);
  53         } else {
  54                 sizeret = SMB_VFS_GETXATTR(handle->conn, smb_fname->base_name,
  55                                            XATTR_NTACL_NAME, val, size);
  56         }
  57         if (sizeret == -1) {
  58                 saved_errno = errno;
  59         }
  60         unbecome_root();
  61
  62         if (saved_errno != 0) {
  63                 errno = saved_errno;
  64         }
  65
  66         return sizeret;
  67 }
  68
  69 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  70                         vfs_handle_struct *handle,
  71                         files_struct *fsp,
  72                         const struct smb_filename *smb_fname,
  73                         DATA_BLOB *pblob)
  74 {
  75         size_t size = 4096;
  76         uint8_t *val = NULL;
  77         uint8_t *tmp;
  78         ssize_t sizeret;
  79
  80         ZERO_STRUCTP(pblob);
  81
  82   again:
  83
  84         tmp = talloc_realloc(ctx, val, uint8_t, size);
  85         if (tmp == NULL) {
  86                 TALLOC_FREE(val);
  87                 return NT_STATUS_NO_MEMORY;
  88         }
  89         val = tmp;
  90
  91         sizeret =
  92             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, val, size);
  93
  94         if (sizeret >= 0) {
  95                 pblob->data = val;
  96                 pblob->length = sizeret;
  97                 return NT_STATUS_OK;
  98         }
  99
 100         if (errno != ERANGE) {
 101                 goto err;
 102         }
 103
 104         /* Too small, try again. */
 105         sizeret =
 106             getxattr_do(handle, fsp, smb_fname, XATTR_NTACL_NAME, NULL, 0);
 107         if (sizeret < 0) {
 108                 goto err;
 109         }
 110
 111         if (size < sizeret) {
 112                 size = sizeret;
 113         }
 114
 115         if (size > 65536) {
 116                 /* Max ACL size is 65536 bytes. */
 117                 errno = ERANGE;
 118                 goto err;
 119         }
 120
 121         goto again;
 122   err:
 123         /* Real error - exit here. */
 124         TALLOC_FREE(val);
 125         return map_nt_error_from_unix(errno);
 126 }
 127
 128 /*******************************************************************
 129  Store a DATA_BLOB into an xattr given an fsp pointer.
 130 *******************************************************************/
 131
 132 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
 133                                 files_struct *fsp,
 134                                 DATA_BLOB *pblob)
 135 {
 136         int ret;
 137         int saved_errno = 0;
 138
 139         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 140                   (unsigned int)pblob->length, fsp_str_dbg(fsp)));
 141
 142         become_root();
 143         if (fsp->fh->fd != -1) {
 144                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 145                         pblob->data, pblob->length, 0);
 146         } else {
 147                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name,
 148                                 XATTR_NTACL_NAME,
 149                                 pblob->data, pblob->length, 0);
 150         }
 151         if (ret) {
 152                 saved_errno = errno;
 153         }
 154         unbecome_root();
 155         if (ret) {
 156                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 157                         "with error %s\n",
 158                         fsp_str_dbg(fsp),
 159                         strerror(saved_errno) ));
 160                 errno = saved_errno;
 161                 return map_nt_error_from_unix(saved_errno);
 162         }
 163         return NT_STATUS_OK;
 164 }
 165
 166 /*********************************************************************
 167  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 168 *********************************************************************/
 169
 170 static int sys_acl_set_file_xattr(vfs_handle_struct *handle,
 171                                 const struct smb_filename *smb_fname,
 172                                 SMB_ACL_TYPE_T type,
 173                                 SMB_ACL_T theacl)
 174 {
 175         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FILE(handle,
 176                                                 smb_fname,
 177                                                 type,
 178                                                 theacl);
 179         if (ret == -1) {
 180                 return -1;
 181         }
 182
 183         become_root();
 184         SMB_VFS_REMOVEXATTR(handle->conn, smb_fname,
 185                         XATTR_NTACL_NAME);
 186         unbecome_root();
 187
 188         return ret;
 189 }
 190
 191 /*********************************************************************
 192  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 193 *********************************************************************/
 194
 195 static int sys_acl_set_fd_xattr(vfs_handle_struct *handle,
 196                             files_struct *fsp,
 197                             SMB_ACL_T theacl)
 198 {
 199         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FD(handle,
 200                                                 fsp,
 201                                                 theacl);
 202         if (ret == -1) {
 203                 return -1;
 204         }
 205
 206         become_root();
 207         SMB_VFS_FREMOVEXATTR(fsp, XATTR_NTACL_NAME);
 208         unbecome_root();
 209
 210         return ret;
 211 }
 212
 213 static int connect_acl_xattr(struct vfs_handle_struct *handle,
 214                                 const char *service,
 215                                 const char *user)
 216 {
 217         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 218         bool ok;
 219         struct acl_common_config *config = NULL;
 220
 221         if (ret < 0) {
 222                 return ret;
 223         }
 224
 225         ok = init_acl_common_config(handle);
 226         if (!ok) {
 227                 DBG_ERR("init_acl_common_config failed\n");
 228                 return -1;
 229         }
 230
 231         /* Ensure we have the parameters correct if we're
 232          * using this module. */
 233         DEBUG(2,("connect_acl_xattr: setting 'inherit acls = true' "
 234                 "'dos filemode = true' and "
 235                 "'force unknown acl user = true' for service %s\n",
 236                 service ));
 237
 238         lp_do_parameter(SNUM(handle->conn), "inherit acls", "true");
 239         lp_do_parameter(SNUM(handle->conn), "dos filemode", "true");
 240         lp_do_parameter(SNUM(handle->conn), "force unknown acl user", "true");
 241
 242         SMB_VFS_HANDLE_GET_DATA(handle, config,
 243                                 struct acl_common_config,
 244                                 return -1);
 245
 246         if (config->ignore_system_acls) {
 247                 mode_t create_mask = lp_create_mask(SNUM(handle->conn));
 248                 char *create_mask_str = NULL;
 249
 250                 if ((create_mask & 0666) != 0666) {
 251                         create_mask |= 0666;
 252                         create_mask_str = talloc_asprintf(handle, "0%o",
 253                                                           create_mask);
 254                         if (create_mask_str == NULL) {
 255                                 DBG_ERR("talloc_asprintf failed\n");
 256                                 return -1;
 257                         }
 258
 259                         DBG_NOTICE("setting 'create mask = %s'\n", create_mask_str);
 260
 261                         lp_do_parameter (SNUM(handle->conn),
 262                                         "create mask", create_mask_str);
 263
 264                         TALLOC_FREE(create_mask_str);
 265                 }
 266
 267                 DBG_NOTICE("setting 'directory mask = 0777', "
 268                            "'store dos attributes = yes' and all "
 269                            "'map ...' options to 'no'\n");
 270
 271                 lp_do_parameter(SNUM(handle->conn), "directory mask", "0777");
 272                 lp_do_parameter(SNUM(handle->conn), "map archive", "no");
 273                 lp_do_parameter(SNUM(handle->conn), "map hidden", "no");
 274                 lp_do_parameter(SNUM(handle->conn), "map readonly", "no");
 275                 lp_do_parameter(SNUM(handle->conn), "map system", "no");
 276                 lp_do_parameter(SNUM(handle->conn), "store dos attributes",
 277                                 "yes");
 278         }
 279
 280         return 0;
 281 }
 282
 283 static struct vfs_fn_pointers vfs_acl_xattr_fns = {
 284         .connect_fn = connect_acl_xattr,
 285         .rmdir_fn = rmdir_acl_common,
 286         .unlink_fn = unlink_acl_common,
 287         .chmod_fn = chmod_acl_module_common,
 288         .fchmod_fn = fchmod_acl_module_common,
 289         .fget_nt_acl_fn = fget_nt_acl_common,
 290         .get_nt_acl_fn = get_nt_acl_common,
 291         .fset_nt_acl_fn = fset_nt_acl_common,
 292         .chmod_acl_fn = chmod_acl_acl_module_common,
 293         .fchmod_acl_fn = fchmod_acl_acl_module_common,
 294         .sys_acl_set_file_fn = sys_acl_set_file_xattr,
 295         .sys_acl_set_fd_fn = sys_acl_set_fd_xattr
 296 };
 297
 298 static_decl_vfs;
 299 NTSTATUS vfs_acl_xattr_init(TALLOC_CTX *ctx)
 300 {
 301         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr",
 302                                 &vfs_acl_xattr_fns);
 303 }