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 "smbd/smbd.h"
  25 #include "librpc/gen_ndr/xattr.h"
  26 #include "librpc/gen_ndr/ndr_xattr.h"
  27 #include "../lib/crypto/crypto.h"
  28 #include "auth.h"
  29
  30 #undef DBGC_CLASS
  31 #define DBGC_CLASS DBGC_VFS
  32
  33 /* Pull in the common functions. */
  34 #define ACL_MODULE_NAME "acl_xattr"
  35
  36 #include "modules/vfs_acl_common.c"
  37
  38 /*******************************************************************
  39  Pull a security descriptor into a DATA_BLOB from a xattr.
  40 *******************************************************************/
  41
  42 static NTSTATUS get_acl_blob(TALLOC_CTX *ctx,
  43                         vfs_handle_struct *handle,
  44                         files_struct *fsp,
  45                         const char *name,
  46                         DATA_BLOB *pblob)
  47 {
  48         size_t size = 1024;
  49         uint8_t *val = NULL;
  50         uint8_t *tmp;
  51         ssize_t sizeret;
  52         int saved_errno = 0;
  53
  54         ZERO_STRUCTP(pblob);
  55
  56   again:
  57
  58         tmp = talloc_realloc(ctx, val, uint8_t, size);
  59         if (tmp == NULL) {
  60                 TALLOC_FREE(val);
  61                 return NT_STATUS_NO_MEMORY;
  62         }
  63         val = tmp;
  64
  65         become_root();
  66         if (fsp && fsp->fh->fd != -1) {
  67                 sizeret = SMB_VFS_FGETXATTR(fsp, XATTR_NTACL_NAME, val, size);
  68         } else {
  69                 sizeret = SMB_VFS_GETXATTR(handle->conn, name,
  70                                         XATTR_NTACL_NAME, val, size);
  71         }
  72         if (sizeret == -1) {
  73                 saved_errno = errno;
  74         }
  75         unbecome_root();
  76
  77         /* Max ACL size is 65536 bytes. */
  78         if (sizeret == -1) {
  79                 errno = saved_errno;
  80                 if ((errno == ERANGE) && (size != 65536)) {
  81                         /* Too small, try again. */
  82                         size = 65536;
  83                         goto again;
  84                 }
  85
  86                 /* Real error - exit here. */
  87                 TALLOC_FREE(val);
  88                 return map_nt_error_from_unix(errno);
  89         }
  90
  91         pblob->data = val;
  92         pblob->length = sizeret;
  93         return NT_STATUS_OK;
  94 }
  95
  96 /*******************************************************************
  97  Store a DATA_BLOB into an xattr given an fsp pointer.
  98 *******************************************************************/
  99
 100 static NTSTATUS store_acl_blob_fsp(vfs_handle_struct *handle,
 101                                 files_struct *fsp,
 102                                 DATA_BLOB *pblob)
 103 {
 104         int ret;
 105         int saved_errno = 0;
 106
 107         DEBUG(10,("store_acl_blob_fsp: storing blob length %u on file %s\n",
 108                   (unsigned int)pblob->length, fsp_str_dbg(fsp)));
 109
 110         become_root();
 111         if (fsp->fh->fd != -1) {
 112                 ret = SMB_VFS_FSETXATTR(fsp, XATTR_NTACL_NAME,
 113                         pblob->data, pblob->length, 0);
 114         } else {
 115                 ret = SMB_VFS_SETXATTR(fsp->conn, fsp->fsp_name->base_name,
 116                                 XATTR_NTACL_NAME,
 117                                 pblob->data, pblob->length, 0);
 118         }
 119         if (ret) {
 120                 saved_errno = errno;
 121         }
 122         unbecome_root();
 123         if (ret) {
 124                 errno = saved_errno;
 125                 DEBUG(5, ("store_acl_blob_fsp: setting attr failed for file %s"
 126                         "with error %s\n",
 127                         fsp_str_dbg(fsp),
 128                         strerror(errno) ));
 129                 return map_nt_error_from_unix(errno);
 130         }
 131         return NT_STATUS_OK;
 132 }
 133
 134 /*********************************************************************
 135  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 136 *********************************************************************/
 137
 138 static int sys_acl_set_file_xattr(vfs_handle_struct *handle,
 139                               const char *name,
 140                               SMB_ACL_TYPE_T type,
 141                               SMB_ACL_T theacl)
 142 {
 143         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FILE(handle,
 144                                                 name,
 145                                                 type,
 146                                                 theacl);
 147         if (ret == -1) {
 148                 return -1;
 149         }
 150
 151         become_root();
 152         SMB_VFS_REMOVEXATTR(handle->conn, name, XATTR_NTACL_NAME);
 153         unbecome_root();
 154
 155         return ret;
 156 }
 157
 158 /*********************************************************************
 159  Remove a Windows ACL - we're setting the underlying POSIX ACL.
 160 *********************************************************************/
 161
 162 static int sys_acl_set_fd_xattr(vfs_handle_struct *handle,
 163                             files_struct *fsp,
 164                             SMB_ACL_T theacl)
 165 {
 166         int ret = SMB_VFS_NEXT_SYS_ACL_SET_FD(handle,
 167                                                 fsp,
 168                                                 theacl);
 169         if (ret == -1) {
 170                 return -1;
 171         }
 172
 173         become_root();
 174         SMB_VFS_FREMOVEXATTR(fsp, XATTR_NTACL_NAME);
 175         unbecome_root();
 176
 177         return ret;
 178 }
 179
 180 static int connect_acl_xattr(struct vfs_handle_struct *handle,
 181                                 const char *service,
 182                                 const char *user)
 183 {
 184         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 185
 186         if (ret < 0) {
 187                 return ret;
 188         }
 189
 190         /* Ensure we have the parameters correct if we're
 191          * using this module. */
 192         DEBUG(2,("connect_acl_xattr: setting 'inherit acls = true' "
 193                 "'dos filemode = true' and "
 194                 "'force unknown acl user = true' for service %s\n",
 195                 service ));
 196
 197         lp_do_parameter(SNUM(handle->conn), "inherit acls", "true");
 198         lp_do_parameter(SNUM(handle->conn), "dos filemode", "true");
 199         lp_do_parameter(SNUM(handle->conn), "force unknown acl user", "true");
 200
 201         return 0;
 202 }
 203
 204 static struct vfs_fn_pointers vfs_acl_xattr_fns = {
 205         .connect_fn = connect_acl_xattr,
 206         .opendir = opendir_acl_common,
 207         .mkdir = mkdir_acl_common,
 208         .rmdir = rmdir_acl_common,
 209         .open_fn = open_acl_common,
 210         .create_file = create_file_acl_common,
 211         .unlink = unlink_acl_common,
 212         .chmod = chmod_acl_module_common,
 213         .fchmod = fchmod_acl_module_common,
 214         .fget_nt_acl = fget_nt_acl_common,
 215         .get_nt_acl = get_nt_acl_common,
 216         .fset_nt_acl = fset_nt_acl_common,
 217         .chmod_acl = chmod_acl_acl_module_common,
 218         .fchmod_acl = fchmod_acl_acl_module_common,
 219         .sys_acl_set_file = sys_acl_set_file_xattr,
 220         .sys_acl_set_fd = sys_acl_set_fd_xattr
 221 };
 222
 223 NTSTATUS vfs_acl_xattr_init(void)
 224 {
 225         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "acl_xattr",
 226                                 &vfs_acl_xattr_fns);
 227 }