Improved support for Unicode Strings inside and ENCODED_STRING value

* In those cases where a list of items was parsed, there were some inconsistencies
* Should address https://github.com/CoreSecurity/impacket/issues/304
* Further testing is needed to be sure we're not breaking anything else.

examples/wmiquery.py

@@ -76,14 +76,19 @@ if __name__ == '__main__':
                     pEnum = iEnum.Next(0xffffffff,1)[0]
                     record = pEnum.getProperties()
                     if printHeader is True:
-                        print '|', 
+                        print '|',
                         for col in record:
                             print '%s |' % col,
                         print
                         printHeader = False
                     print '|', 
                     for key in record:
-                        print '%s |' % record[key]['value'],
+                        if type(record[key]['value']) is list:
+                            for item in record[key]['value']:
+                                print item,
+                            print ' |',
+                        else:
+                            print '%s |' % record[key]['value'],
                     print 
                 except Exception, e:
                     #import traceback

impacket/dcerpc/v5/dcom/wmi.py

@@ -136,26 +136,27 @@ class ENCODED_STRING(Structure):
             # Let's first check the commonHdr
             self.fromString(data)
             self.structure = ()
+            self.isUnicode = False
             if len(data) > 1:
                 if self['Encoded_String_Flag'] == 0:
                     self.structure += self.tascii
                     # Let's search for the end of the string
                     index = data[1:].find('\x00')
                     data  = data[:index+1+1]
-                    self.fromString(data)
                 else:
                     self.structure = self.tunicode
-                    # index = data[1:].find('\x00\x00')
-                    # data = data[:index+1+2]
-                    self.fromString(data)
-                    try:
-                        self['Character'] = self['Character'].decode('utf-16le')
-                    except UnicodeDecodeError:
-                        pass
+                    self.isUnicode = True
+
+                self.fromString(data)
         else:
             self.structure = self.tascii
             self.data = None
 
+    def __getitem__(self, key):
+        if key == 'Character' and self.isUnicode:
+            return self.fields['Character'].decode('utf-16le')
+        return Structure.__getitem__(self, key)
+
 
 # 2.2.8 DecServerName
 DEC_SERVER_NAME = ENCODED_STRING