source3/modules/vfs_linux_xfs_sgid.c

   1 /*
   2  * Module to work around a bug in Linux XFS:
   3  * http://oss.sgi.com/bugzilla/show_bug.cgi?id=280
   4  *
   5  * Copyright (c) Volker Lendecke 2010
   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 "system/filesys.h"
  23 #include "smbd/smbd.h"
  24
  25 static int linux_xfs_sgid_mkdirat(vfs_handle_struct *handle,
  26                 struct files_struct *dirfsp,
  27                 const struct smb_filename *smb_fname,
  28                 mode_t mode)
  29 {
  30         struct smb_filename *dname = NULL;
  31         struct smb_filename *fname = NULL;
  32         int mkdir_res;
  33         int res;
  34         NTSTATUS status;
  35
  36         DEBUG(10, ("Calling linux_xfs_sgid_mkdirat(%s)\n",
  37                 smb_fname->base_name));
  38
  39         mkdir_res = SMB_VFS_NEXT_MKDIRAT(handle,
  40                         dirfsp,
  41                         smb_fname,
  42                         mode);
  43         if (mkdir_res == -1) {
  44                 DEBUG(10, ("SMB_VFS_NEXT_MKDIRAT returned error: %s\n",
  45                            strerror(errno)));
  46                 return mkdir_res;
  47         }
  48
  49         fname = full_path_from_dirfsp_atname(talloc_tos(),
  50                                              dirfsp,
  51                                              smb_fname);
  52         if (fname == NULL) {
  53                 return -1;
  54         }
  55
  56         status = SMB_VFS_PARENT_PATHNAME(handle->conn,
  57                                          talloc_tos(),
  58                                          fname,
  59                                          &dname,
  60                                          NULL);
  61         if (!NT_STATUS_IS_OK(status)) {
  62                 DBG_WARNING("SMB_VFS_PARENT_PATHNAME() failed with %s\n",
  63                         nt_errstr(status));
  64                 /* return success, we did the mkdir */
  65                 return mkdir_res;
  66         }
  67
  68         res = SMB_VFS_NEXT_STAT(handle, dname);
  69         if (res == -1) {
  70                 DBG_DEBUG("NEXT_STAT(%s) failed: %s\n",
  71                           smb_fname_str_dbg(dname),
  72                           strerror(errno));
  73                 /* return success, we did the mkdir */
  74                 return mkdir_res;
  75         }
  76         if ((dname->st.st_ex_mode & S_ISGID) == 0) {
  77                 /* No SGID to inherit */
  78                 DEBUG(10, ("No SGID to inherit\n"));
  79                 TALLOC_FREE(dname);
  80                 return mkdir_res;
  81         }
  82         TALLOC_FREE(dname);
  83
  84         res = SMB_VFS_NEXT_STAT(handle, fname);
  85         if (res == -1) {
  86                 DBG_NOTICE("Could not stat just created dir %s: %s\n",
  87                            smb_fname_str_dbg(fname),
  88                            strerror(errno));
  89                 /* return success, we did the mkdir */
  90                 TALLOC_FREE(fname);
  91                 return mkdir_res;
  92         }
  93         fname->st.st_ex_mode |= S_ISGID;
  94         fname->st.st_ex_mode &= ~S_IFDIR;
  95
  96         /*
  97          * Yes, we have to do this as root. If you do it as
  98          * non-privileged user, XFS on Linux will just ignore us and
  99          * return success. What can you do...
 100          */
 101         become_root();
 102         res = SMB_VFS_NEXT_FCHMOD(handle, smb_fname->fsp, fname->st.st_ex_mode);
 103         unbecome_root();
 104
 105         if (res == -1) {
 106                 DBG_NOTICE("CHMOD(%s, %o) failed: %s\n",
 107                            smb_fname_str_dbg(fname),
 108                            (int)fname->st.st_ex_mode,
 109                            strerror(errno));
 110                 /* return success, we did the mkdir */
 111                 TALLOC_FREE(fname);
 112                 return mkdir_res;
 113         }
 114
 115         TALLOC_FREE(fname);
 116         return mkdir_res;
 117 }
 118
 119 static struct vfs_fn_pointers linux_xfs_sgid_fns = {
 120         .mkdirat_fn = linux_xfs_sgid_mkdirat,
 121 };
 122
 123 static_decl_vfs;
 124 NTSTATUS vfs_linux_xfs_sgid_init(TALLOC_CTX *ctx)
 125 {
 126         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 127                                 "linux_xfs_sgid", &linux_xfs_sgid_fns);
 128 }