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,
  26                 const struct smb_filename *smb_fname,
  27                 mode_t mode)
  28 {
  29         struct smb_filename fname = { 0, };
  30         int mkdir_res;
  31         int res;
  32
  33         DEBUG(10, ("Calling linux_xfs_sgid_mkdir(%s)\n", smb_fname->base_name));
  34
  35         mkdir_res = SMB_VFS_NEXT_MKDIR(handle, smb_fname, mode);
  36         if (mkdir_res == -1) {
  37                 DEBUG(10, ("SMB_VFS_NEXT_MKDIR returned error: %s\n",
  38                            strerror(errno)));
  39                 return mkdir_res;
  40         }
  41
  42         if (!parent_dirname(talloc_tos(),
  43                         smb_fname->base_name,
  44                         &fname.base_name,
  45                         NULL)) {
  46                 DEBUG(1, ("parent_dirname failed\n"));
  47                 /* return success, we did the mkdir */
  48                 return mkdir_res;
  49         }
  50
  51         res = SMB_VFS_NEXT_STAT(handle, &fname);
  52         if (res == -1) {
  53                 DEBUG(10, ("NEXT_STAT(%s) failed: %s\n", fname.base_name,
  54                            strerror(errno)));
  55                 /* return success, we did the mkdir */
  56                 return mkdir_res;
  57         }
  58         TALLOC_FREE(fname.base_name);
  59         if ((fname.st.st_ex_mode & S_ISGID) == 0) {
  60                 /* No SGID to inherit */
  61                 DEBUG(10, ("No SGID to inherit\n"));
  62                 return mkdir_res;
  63         }
  64
  65         fname.base_name = discard_const_p(char, smb_fname->base_name);
  66
  67         res = SMB_VFS_NEXT_STAT(handle, &fname);
  68         if (res == -1) {
  69                 DEBUG(2, ("Could not stat just created dir %s: %s\n",
  70                         smb_fname->base_name,
  71                         strerror(errno)));
  72                 /* return success, we did the mkdir */
  73                 return mkdir_res;
  74         }
  75         fname.st.st_ex_mode |= S_ISGID;
  76         fname.st.st_ex_mode &= ~S_IFDIR;
  77
  78         /*
  79          * Yes, we have to do this as root. If you do it as
  80          * non-privileged user, XFS on Linux will just ignore us and
  81          * return success. What can you do...
  82          */
  83         become_root();
  84         res = SMB_VFS_NEXT_CHMOD(handle,
  85                         smb_fname,
  86                         fname.st.st_ex_mode);
  87         unbecome_root();
  88
  89         if (res == -1) {
  90                 DEBUG(2, ("CHMOD(%s, %o) failed: %s\n", smb_fname->base_name,
  91                           (int)fname.st.st_ex_mode, strerror(errno)));
  92                 /* return success, we did the mkdir */
  93                 return mkdir_res;
  94         }
  95         return mkdir_res;
  96 }
  97
  98 static int linux_xfs_sgid_chmod_acl(vfs_handle_struct *handle,
  99                         const struct smb_filename *smb_fname,
 100                         mode_t mode)
 101 {
 102         errno = ENOSYS;
 103         return -1;
 104 }
 105
 106 static struct vfs_fn_pointers linux_xfs_sgid_fns = {
 107         .mkdir_fn = linux_xfs_sgid_mkdir,
 108         .chmod_acl_fn = linux_xfs_sgid_chmod_acl,
 109 };
 110
 111 NTSTATUS vfs_linux_xfs_sgid_init(void);
 112 NTSTATUS vfs_linux_xfs_sgid_init(void)
 113 {
 114         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,
 115                                 "linux_xfs_sgid", &linux_xfs_sgid_fns);
 116 }