python: Implement OpenPolicyFallback()

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

python/samba/lsa_utils.py

@@ -18,10 +18,54 @@
 
 from samba.dcerpc import lsa, drsblobs
 from samba.ndr import ndr_pack
-from samba import arcfour_encrypt, string_to_byte_array
+from samba import NTSTATUSError, arcfour_encrypt, string_to_byte_array
+from samba.ntstatus import (
+    NT_STATUS_RPC_PROCNUM_OUT_OF_RANGE
+)
 import random
 from samba import crypto
 
+
+def OpenPolicyFallback(
+    conn: lsa.lsarpc,
+    system_name: str,
+    in_version: int,
+    in_revision_info: lsa.revision_info1,
+    sec_qos: bool = False,
+    access_mask: int = 0,
+):
+    attr = lsa.ObjectAttribute()
+    if sec_qos:
+        qos = lsa.QosInfo()
+        qos.len = 0xc
+        qos.impersonation_level = 2
+        qos.context_mode = 1
+        qos.effective_only = 0
+
+        attr.sec_qos = qos
+
+    try:
+        out_version, out_rev_info, policy = conn.OpenPolicy3(
+            system_name,
+            attr,
+            access_mask,
+            in_version,
+            in_revision_info
+        )
+    except NTSTATUSError as e:
+        if e.args[0] == NT_STATUS_RPC_PROCNUM_OUT_OF_RANGE:
+            out_version = 1
+            out_rev_info = lsa.revision_info1()
+            out_rev_info.revision = 1
+            out_rev_info.supported_features = 0
+
+            policy = conn.OpenPolicy2(system_name, attr, access_mask)
+        else:
+            raise
+
+    return out_version, out_rev_info, policy
+
+
 def CreateTrustedDomainRelax(lsaconn, policy, trust_info, mask, in_blob, out_blob):
 
     def generate_AuthInfoInternal(session_key, incoming=None, outgoing=None):

python/samba/tests/dcerpc/createtrustrelax.py

@@ -24,7 +24,7 @@ import samba
 from samba.tests import TestCase
 from samba.dcerpc import lsa, security, drsblobs
 from samba.credentials import Credentials, SMB_ENCRYPTION_REQUIRED, SMB_ENCRYPTION_OFF
-from samba.lsa_utils import CreateTrustedDomainRelax
+from samba.lsa_utils import OpenPolicyFallback, CreateTrustedDomainRelax
 
 class CreateTrustedDomainRelaxTest(TestCase):
 
@@ -57,12 +57,20 @@ class CreateTrustedDomainRelaxTest(TestCase):
         else:
             self.assertFalse(lsa_conn.transport_encrypted())
 
-        objectAttr = lsa.ObjectAttribute()
+        in_version = 1
-        objectAttr.sec_qos = lsa.QosInfo()
+        in_revision_info1 = lsa.revision_info1()
+        in_revision_info1.revision = 1
+        in_revision_info1.supported_features = (
+            lsa.LSA_FEATURE_TDO_AUTH_INFO_AES_CIPHER
+        )
 
-        pol_handle = lsa_conn.OpenPolicy2('',
+        out_version, out_revision_info1, pol_handle = OpenPolicyFallback(
-                                          objectAttr,
+            lsa_conn,
-                                          security.SEC_FLAG_MAXIMUM_ALLOWED)
+            '',
+            in_version,
+            in_revision_info1,
+            access_mask=security.SEC_FLAG_MAXIMUM_ALLOWED
+        )
         self.assertIsNotNone(pol_handle)
 
         name = lsa.String()