common: return standard CEL event log instead of encoded ones (#117)

common/python/cctrusted_base/eventlog.py

@@ -40,9 +40,10 @@ class TcgEventLog:
  """
 
  TCG_FORMAT_PCCLIENT = 0
- TCG_FORMAT_CEL_TLV = 1
- TCG_FORMAT_CEL_JSON = 2
- TCG_FORMAT_CEL_CBOR = 3
+ TCG_FORMAT_CEL = 1
+ TCG_FORMAT_CEL_TLV = 2
+ TCG_FORMAT_CEL_JSON = 3
+ TCG_FORMAT_CEL_CBOR = 4
 
  def __init__(self, rec_num:int, imr_index:int, event_type:TcgEventType, digests:list[TcgDigest],
  event_size:int, event:bytes, extra_info=None) -> None:
@@ -59,9 +60,8 @@ def format_event_log(self, parse_format:str):
  if parse_format == self.TCG_FORMAT_PCCLIENT:
  return self._to_tcg_pcclient_format()
 
- if parse_format in (self.TCG_FORMAT_CEL_JSON, self.TCG_FORMAT_CEL_CBOR,
- self.TCG_FORMAT_CEL_TLV) :
- return self._to_tcg_canonical_format(parse_format)
+ if parse_format == self.TCG_FORMAT_CEL :
+ return self._to_tcg_canonical_format()
 
  return None
 
@@ -79,7 +79,7 @@ def _to_tcg_pcclient_format(self):
  return TcgImrEvent(self._imr_index, self._event_type, self._digests, self._event_size,
  self._event)
 
- def _to_tcg_canonical_format(self, encoding:str=None):
+ def _to_tcg_canonical_format(self):
  """The function to convert event log data into event log following
  Canonical Eventlog Spec.
  """
@@ -101,8 +101,9 @@ def _to_tcg_canonical_format(self, encoding:str=None):
  None,
  content_data)
 
- # switch encoding according to user input
- return TcgTpmsCelEvent.encode(event, encoding)
+ # return basic CEL event
+ # can switch encoding by calling the TcgTpmsCelEvent.encoding()
+ return event
 
 class EventLogs:
  """EventLogs class.
@@ -251,7 +252,7 @@ def _parse(self) -> None:
  for event in self._runtime_data.splitlines():
  event_log = self._parse_ima_event_log(event)
  self._event_logs.append(
- event_log.format_event_log(TcgEventLog.TCG_FORMAT_CEL_TLV))
+ event_log.format_event_log(TcgEventLog.TCG_FORMAT_CEL))
  self._count += 1
 
  def _parse_spec_id_event_log(self, data:bytes) -> (TcgEventLog, int):
@@ -452,22 +453,21 @@ def replay(event_logs:list) -> dict:
  # TODO: consider CEL-JSON/CEL-CBOR encoding later
  # extract common attributes from different formats, only consider TLV encoding for now
  if isinstance(event, TcgTpmsCelEvent):
- content_type = event.content.type
+ content_type = event.content_type
  # Align the Canonical types with TCG PCClient Event types
  match content_type:
  case TcgCelTypes.CEL_IMA_TEMPLATE:
  event_type = TcgEventType.IMA_MEASUREMENT_EVENT
  case TcgCelTypes.CEL_PCCLIENT_STD:
  # For PCClient_STD event,
  # the event type is store within the content attribute
- event_type = event.content.value[0].value
+ # event_type = event.content.value[0].value
+ event_type = event.content.event_type
 
  # TODO: consider the NV_INDEX case later
- imr_index = event.index.value
+ imr_index = event.index
 
- digests = []
- for d in event.digests.value:
- digests.append(TcgDigest(d.type, d.value))
+ digests = event.digests
  else:
  event_type = event.event_type
  # Skip EV_NO_ACTION event during replay as

common/python/cctrusted_base/tcgcel.py

@@ -5,6 +5,8 @@
 from abc import abstractmethod
 from cctrusted_base.tcg import TcgDigest
 from cctrusted_base.tcg import TcgAlgorithmRegistry
+from cctrusted_base.tcg import TcgEventType
+from cctrusted_base.eventlog import TcgImrEvent
 from cctrusted_base.binaryblob import BinaryBlob
 
 LOG = logging.getLogger(__name__)
@@ -83,33 +85,50 @@ def set_digests(self, digests):
 
  @property
  def content(self):
- """Content of the event.a"""
+ """Content of the event."""
  return self._content
 
  def set_content(self, content):
  """Set formatted value for content."""
  self._content = content
 
+ @property
+ def content_type(self):
+ """Content type of event."""
+ return self._content_type
+
  def encoding(self):
  """Get the encoding format of the event"""
  return self._encoding
 
+ def to_pcclient_format(self):
+ """Convert CEL event log to PCClient format"""
+ if self._content_type == TcgCelTypes.CEL_IMA_TEMPLATE:
+ event = self.content.template_data
+ return TcgImrEvent(self._imr, TcgEventType.IMA_MEASUREMENT_EVENT,
+ self._digests, len(event), event)
+ if self._content_type == TcgCelTypes.CEL_PCCLIENT_STD:
+ return TcgImrEvent(self._imr, self.content.event_type, self._digests,
+ len(self.content.event_data), self.content.event_data)
+ LOG.error("Unsupported content to parse into TCG PCClient format.")
+ return None
+
  @staticmethod
- def encode(obj, encoding:int=1):
+ def encode(obj, encoding:int=2):
  """Encode the CEL record in certain format"""
  match encoding:
- # TCG_FORMAT_CEL_TLV = 1
- case 1:
+ # TcgEventLog.TCG_FORMAT_CEL_TLV = 2
+ case 2:
  # pylint: disable-next=w0212
  obj._encoding = "TLV"
  return TcgTpmsCelEvent._encoded_in_tlv(obj)
- # TCG_FORMAT_CEL_JSON = 2
- case 2:
+ # TcgEventLog.TCG_FORMAT_CEL_JSON = 3
+ case 3:
  # pylint: disable-next=w0212
  obj._encoding = "JSON"
  return TcgTpmsCelEvent._encoded_in_json(obj)
- # TCG_FORMAT_CEL_CBOR = 3
- case 3:
+ # TcgEventLog.TCG_FORMAT_CEL_JSON = 4
+ case 4:
  # pylint: disable-next=w0212
  obj._encoding = "CBOR"
  return TcgTpmsCelEvent._encoded_in_cbor(obj)