python/samba/ntacls.py

   1 # Unix SMB/CIFS implementation.
   2 # Copyright (C) Matthieu Patou <mat@matws.net> 2009-2010
   3 #
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 3 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 #
  18
  19 """NT Acls."""
  20
  21
  22 import os
  23 import samba.xattr_native, samba.xattr_tdb, samba.posix_eadb
  24 from samba.dcerpc import security, xattr, idmap
  25 from samba.ndr import ndr_pack, ndr_unpack
  26 from samba.samba3 import smbd
  27
  28 class XattrBackendError(Exception):
  29     """A generic xattr backend error."""
  30
  31
  32 def checkset_backend(lp, backend, eadbfile):
  33     '''return the path to the eadb, or None'''
  34     if backend is None:
  35         xattr_tdb = lp.get("xattr_tdb:file")
  36         if xattr_tdb is not None:
  37             return (samba.xattr_tdb, lp.get("xattr_tdb:file"))
  38         posix_eadb = lp.get("posix:eadb")
  39         if posix_eadb is not None:
  40             return (samba.posix_eadb, lp.get("posix:eadb"))
  41         return (None, None)
  42     elif backend == "native":
  43         return (None, None)
  44     elif backend == "eadb":
  45         if eadbfile is not None:
  46             return (samba.posix_eadb, eadbfile)
  47         else:
  48             return (samba.posix_eadb, os.path.abspath(os.path.join(lp.get("private dir"), "eadb.tdb")))
  49     elif backend == "tdb":
  50         if eadbfile is not None:
  51             return (samba.xattr_tdb, eadbfile)
  52         else:
  53             return (samba.xattr_tdb, os.path.abspath(os.path.join(lp.get("state dir"), "xattr.tdb")))
  54     else:
  55         raise XattrBackendError("Invalid xattr backend choice %s"%backend)
  56
  57
  58 def getntacl(lp, file, backend=None, eadbfile=None, direct_db_access=True, service=None):
  59     if direct_db_access:
  60         (backend_obj, dbname) = checkset_backend(lp, backend, eadbfile)
  61         if dbname is not None:
  62             try:
  63                 attribute = backend_obj.wrap_getxattr(dbname, file,
  64                                                       xattr.XATTR_NTACL_NAME)
  65             except Exception:
  66                 # FIXME: Don't catch all exceptions, just those related to opening
  67                 # xattrdb
  68                 print "Fail to open %s" % dbname
  69                 attribute = samba.xattr_native.wrap_getxattr(file,
  70                                                              xattr.XATTR_NTACL_NAME)
  71         else:
  72             attribute = samba.xattr_native.wrap_getxattr(file,
  73                                                          xattr.XATTR_NTACL_NAME)
  74         ntacl = ndr_unpack(xattr.NTACL, attribute)
  75         if ntacl.version == 1:
  76             return ntacl.info
  77         elif ntacl.version == 2:
  78             return ntacl.info.sd
  79         elif ntacl.version == 3:
  80             return ntacl.info.sd
  81         elif ntacl.version == 4:
  82             return ntacl.info.sd
  83     else:
  84         return smbd.get_nt_acl(file, security.SECINFO_OWNER | security.SECINFO_GROUP | security.SECINFO_DACL | security.SECINFO_SACL, service=service)
  85
  86
  87 def setntacl(lp, file, sddl, domsid, backend=None, eadbfile=None, use_ntvfs=True, skip_invalid_chown=False, passdb=None, service=None):
  88     assert(isinstance(domsid, str) or isinstance(domsid, security.dom_sid))
  89     if isinstance(domsid, str):
  90         sid = security.dom_sid(domsid)
  91     elif isinstance(domsid, security.dom_sid):
  92         sid = domsid
  93         domsid = str(sid)
  94
  95     assert(isinstance(sddl, str) or isinstance(sddl, security.descriptor))
  96     if isinstance(sddl, str):
  97         sd = security.descriptor.from_sddl(sddl, sid)
  98     elif isinstance(sddl, security.descriptor):
  99         sd = sddl
 100         sddl = sd.as_sddl(sid)
 101
 102     if not use_ntvfs and skip_invalid_chown:
 103         # Check if the owner can be resolved as a UID
 104         (owner_id, owner_type) = passdb.sid_to_id(sd.owner_sid)
 105         if ((owner_type != idmap.ID_TYPE_UID) and (owner_type != idmap.ID_TYPE_BOTH)):
 106             # Check if this particular owner SID was domain admins,
 107             # because we special-case this as mapping to
 108             # 'administrator' instead.
 109             if sd.owner_sid == security.dom_sid("%s-%d" % (domsid, security.DOMAIN_RID_ADMINS)):
 110                 administrator = security.dom_sid("%s-%d" % (domsid, security.DOMAIN_RID_ADMINISTRATOR))
 111                 (admin_id, admin_type) = passdb.sid_to_id(administrator)
 112
 113                 # Confirm we have a UID for administrator
 114                 if ((admin_type == idmap.ID_TYPE_UID) or (admin_type == idmap.ID_TYPE_BOTH)):
 115
 116                     # Set it, changing the owner to 'administrator' rather than domain admins
 117                     sd2 = sd
 118                     sd2.owner_sid = administrator
 119
 120                     smbd.set_nt_acl(file, security.SECINFO_OWNER |security.SECINFO_GROUP | security.SECINFO_DACL | security.SECINFO_SACL, sd2, service=service)
 121
 122                     # and then set an NTVFS ACL (which does not set the posix ACL) to pretend the owner really was set
 123                     use_ntvfs = True
 124                 else:
 125                     raise XattrBackendError("Unable to find UID for domain administrator %s, got id %d of type %d" % (administrator, admin_id, admin_type))
 126             else:
 127                 # For all other owning users, reset the owner to root
 128                 # and then set the ACL without changing the owner
 129                 #
 130                 # This won't work in test environments, as it tries a real (rather than xattr-based fake) chown
 131
 132                 os.chown(file, 0, 0)
 133                 smbd.set_nt_acl(file, security.SECINFO_GROUP | security.SECINFO_DACL | security.SECINFO_SACL, sd, service=service)
 134
 135     if use_ntvfs:
 136         (backend_obj, dbname) = checkset_backend(lp, backend, eadbfile)
 137         ntacl = xattr.NTACL()
 138         ntacl.version = 1
 139         ntacl.info = sd
 140         if dbname is not None:
 141             try:
 142                 backend_obj.wrap_setxattr(dbname,
 143                                           file, xattr.XATTR_NTACL_NAME, ndr_pack(ntacl))
 144             except Exception:
 145                 # FIXME: Don't catch all exceptions, just those related to opening
 146                 # xattrdb
 147                 print "Fail to open %s" % dbname
 148                 samba.xattr_native.wrap_setxattr(file, xattr.XATTR_NTACL_NAME,
 149                                                  ndr_pack(ntacl))
 150         else:
 151             samba.xattr_native.wrap_setxattr(file, xattr.XATTR_NTACL_NAME,
 152                                              ndr_pack(ntacl))
 153     else:
 154         smbd.set_nt_acl(file, security.SECINFO_OWNER | security.SECINFO_GROUP | security.SECINFO_DACL | security.SECINFO_SACL, sd, service=service)
 155
 156
 157 def ldapmask2filemask(ldm):
 158     """Takes the access mask of a DS ACE and transform them in a File ACE mask.
 159     """
 160     RIGHT_DS_CREATE_CHILD     = 0x00000001
 161     RIGHT_DS_DELETE_CHILD     = 0x00000002
 162     RIGHT_DS_LIST_CONTENTS    = 0x00000004
 163     ACTRL_DS_SELF             = 0x00000008
 164     RIGHT_DS_READ_PROPERTY    = 0x00000010
 165     RIGHT_DS_WRITE_PROPERTY   = 0x00000020
 166     RIGHT_DS_DELETE_TREE      = 0x00000040
 167     RIGHT_DS_LIST_OBJECT      = 0x00000080
 168     RIGHT_DS_CONTROL_ACCESS   = 0x00000100
 169     FILE_READ_DATA            = 0x0001
 170     FILE_LIST_DIRECTORY       = 0x0001
 171     FILE_WRITE_DATA           = 0x0002
 172     FILE_ADD_FILE             = 0x0002
 173     FILE_APPEND_DATA          = 0x0004
 174     FILE_ADD_SUBDIRECTORY     = 0x0004
 175     FILE_CREATE_PIPE_INSTANCE = 0x0004
 176     FILE_READ_EA              = 0x0008
 177     FILE_WRITE_EA             = 0x0010
 178     FILE_EXECUTE              = 0x0020
 179     FILE_TRAVERSE             = 0x0020
 180     FILE_DELETE_CHILD         = 0x0040
 181     FILE_READ_ATTRIBUTES      = 0x0080
 182     FILE_WRITE_ATTRIBUTES     = 0x0100
 183     DELETE                    = 0x00010000
 184     READ_CONTROL              = 0x00020000
 185     WRITE_DAC                 = 0x00040000
 186     WRITE_OWNER               = 0x00080000
 187     SYNCHRONIZE               = 0x00100000
 188     STANDARD_RIGHTS_ALL       = 0x001F0000
 189
 190     filemask = ldm & STANDARD_RIGHTS_ALL
 191
 192     if (ldm & RIGHT_DS_READ_PROPERTY) and (ldm & RIGHT_DS_LIST_CONTENTS):
 193         filemask = filemask | (SYNCHRONIZE | FILE_LIST_DIRECTORY |
 194                                 FILE_READ_ATTRIBUTES | FILE_READ_EA |
 195                                 FILE_READ_DATA | FILE_EXECUTE)
 196
 197     if ldm & RIGHT_DS_WRITE_PROPERTY:
 198         filemask = filemask | (SYNCHRONIZE | FILE_WRITE_DATA |
 199                                 FILE_APPEND_DATA | FILE_WRITE_EA |
 200                                 FILE_WRITE_ATTRIBUTES | FILE_ADD_FILE |
 201                                 FILE_ADD_SUBDIRECTORY)
 202
 203     if ldm & RIGHT_DS_CREATE_CHILD:
 204         filemask = filemask | (FILE_ADD_SUBDIRECTORY | FILE_ADD_FILE)
 205
 206     if ldm & RIGHT_DS_DELETE_CHILD:
 207         filemask = filemask | FILE_DELETE_CHILD
 208
 209     return filemask
 210
 211
 212 def dsacl2fsacl(dssddl, sid, as_sddl=True):
 213     """
 214
 215     This function takes an the SDDL representation of a DS
 216     ACL and return the SDDL representation of this ACL adapted
 217     for files. It's used for Policy object provision
 218     """
 219     ref = security.descriptor.from_sddl(dssddl, sid)
 220     fdescr = security.descriptor()
 221     fdescr.owner_sid = ref.owner_sid
 222     fdescr.group_sid = ref.group_sid
 223     fdescr.type = ref.type
 224     fdescr.revision = ref.revision
 225     aces = ref.dacl.aces
 226     for i in range(0, len(aces)):
 227         ace = aces[i]
 228         if not ace.type & security.SEC_ACE_TYPE_ACCESS_ALLOWED_OBJECT and str(ace.trustee) != security.SID_BUILTIN_PREW2K:
 229        #    if fdescr.type & security.SEC_DESC_DACL_AUTO_INHERITED:
 230             ace.flags = ace.flags | security.SEC_ACE_FLAG_OBJECT_INHERIT | security.SEC_ACE_FLAG_CONTAINER_INHERIT
 231             if str(ace.trustee) == security.SID_CREATOR_OWNER:
 232                 # For Creator/Owner the IO flag is set as this ACE has only a sense for child objects
 233                 ace.flags = ace.flags | security.SEC_ACE_FLAG_INHERIT_ONLY
 234             ace.access_mask =  ldapmask2filemask(ace.access_mask)
 235             fdescr.dacl_add(ace)
 236
 237     if not as_sddl:
 238         return fdescr
 239
 240     return fdescr.as_sddl(sid)