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_mkdir(vfs_handle_struct *handle,  const char *path, mode_t mode)
  26 {
  27         struct smb_filename fname = { 0, };
  28         int mkdir_res;
  29         int res;
  30
  31         DEBUG(10, ("Calling linux_xfs_sgid_mkdir(%s)\n", path));
  32
  33         mkdir_res = SMB_VFS_NEXT_MKDIR(handle, path, mode);
  34         if (mkdir_res == -1) {
  35                 DEBUG(10, ("SMB_VFS_NEXT_MKDIR returned error: %s\n",
  36                            strerror(errno)));
  37                 return mkdir_res;
  38         }
  39
  40         if (!parent_dirname(talloc_tos(), path, &fname.base_name, NULL)) {
  41                 DEBUG(1, ("parent_dirname failed\n"));
  42                 /* return success, we did the mkdir */
  43                 return mkdir_res;
  44         }
  45
  46         res = SMB_VFS_NEXT_STAT(handle, &fname);
  47         if (res == -1) {
  48                 DEBUG(10, ("NEXT_STAT(%s) failed: %s\n", fname.base_name,
  49                            strerror(errno)));
  50                 /* return success, we did the mkdir */
  51                 return mkdir_res;
  52         }
  53         TALLOC_FREE(fname.base_name);
  54         if ((fname.st.st_ex_mode & S_ISGID) == 0) {
  55                 /* No SGID to inherit */
  56                 DEBUG(10, ("No SGID to inherit\n"));
  57                 return mkdir_res;
  58         }
  59
  60         fname.base_name = discard_const_p(char, path);
  61
  62         res = SMB_VFS_NEXT_STAT(handle, &fname);
  63         if (res == -1) {
  64                 DEBUG(2, ("Could not stat just created dir %s: %s\n", path,
  65                           strerror(errno)));
  66                 /* return success, we did the mkdir */
  67                 return mkdir_res;
  68         }
  69         fname.st.st_ex_mode |= S_ISGID;
  70         fname.st.st_ex_mode &= ~S_IFDIR;
  71
  72         /*
  73          * Yes, we have to do this as root. If you do it as
  74          * non-privileged user, XFS on Linux will just ignore us and
  75          * return success. What can you do...
  76          */
  77         become_root();
  78         res = SMB_VFS_NEXT_CHMOD(handle, path, fname.st.st_ex_mode);
  79         unbecome_root();
  80
  81         if (res == -1) {
  82                 DEBUG(2, ("CHMOD(%s, %o) failed: %s\n", path,
  83                           (int)fname.st.st_ex_mode, strerror(errno)));
  84                 /* return success, we did the mkdir */
  85                 return mkdir_res;
  86         }
  87         return mkdir_res;
  88 }
  89
  90 static int linux_xfs_sgid_chmod_acl(vfs_handle_struct *handle,
  91                                     const char *name, mode_t mode)
  92 {
  93         errno = ENOSYS;
  94         return -1;
  95 }
  96
  97 static struct vfs_fn_pointers linux_xfs_sgid_fns = {
  98         .mkdir = linux_xfs_sgid_mkdir,
  99         .chmod_acl = linux_xfs_sgid_chmod_acl,
 100 };
 101
 102 NTSTATUS vfs_linux_xfs_sgid_init(void);
 103 NTSTATUS vfs_linux_xfs_sgid_init(void)
 104 {
 105         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 106                                 "linux_xfs_sgid", &linux_xfs_sgid_fns);
 107 }