def testWireFormatAccess(self):
m = rdfvalue.SignedMessageList()
now = 1369308998000000
# An unset RDFDatetime with no defaults will be None.
self.assertEqual(m.timestamp, None)
# Set the wireformat to the integer equivalent.
m.SetWireFormat("timestamp", now)
self.assertTrue(isinstance(m.timestamp, rdfvalue.RDFDatetime))
self.assertEqual(m.timestamp, now)
rdf_now = rdfvalue.RDFDatetime().Now()
m.timestamp = rdf_now
self.assertEqual(m.GetWireFormat("timestamp"), int(rdf_now))
def EncodeMessages(self,
message_list,
result,
destination=None,
timestamp=None,
api_version=3):
"""Accepts a list of messages and encodes for transmission.
This function signs and then encrypts the payload.
Args:
message_list: A MessageList rdfvalue containing a list of
GrrMessages.
result: A ClientCommunication rdfvalue which will be filled in.
destination: The CN of the remote system this should go to.
timestamp: A timestamp to use for the signed messages. If None - use the
current time.
api_version: The api version which this should be encoded in.
Returns:
A nonce (based on time) which is inserted to the encrypted payload. The
client can verify that the server is able to decrypt the message and
return the nonce.
Raises:
RuntimeError: If we do not support this api version.
"""
if api_version not in [3]:
raise RuntimeError("Unsupported api version: %s, expected 3." %
api_version)
if destination is None:
destination = self.server_name
# Make a nonce for this transaction
if timestamp is None:
self.timestamp = timestamp = long(time.time() * 1000000)
# Do we have a cached cipher to talk to this destination?
try:
cipher = self.cipher_cache.Get(destination)
except KeyError:
# Make a new one
cipher = Cipher(self.common_name, destination, self.private_key,
self.pub_key_cache)
self.cipher_cache.Put(destination, cipher)
signed_message_list = rdfvalue.SignedMessageList(timestamp=timestamp)
self.EncodeMessageList(message_list, signed_message_list)
result.encrypted_cipher_metadata = cipher.encrypted_cipher_metadata
# Include the encrypted cipher.
result.encrypted_cipher = cipher.encrypted_cipher
serialized_message_list = signed_message_list.SerializeToString()
# Encrypt the message symmetrically.
# New scheme cipher is signed plus hmac over message list.
result.packet_iv, result.encrypted = cipher.Encrypt(
serialized_message_list)
# This is to support older endpoints.
result.hmac = cipher.HMAC(result.encrypted)
# Newer endpoints only look at this HMAC. It is recalculated for each packet
# in the session. Note that encrypted_cipher and encrypted_cipher_metadata
# do not change between all packets in this session.
result.full_hmac = cipher.HMAC(result.encrypted,
result.encrypted_cipher,
result.encrypted_cipher_metadata,
result.packet_iv,
struct.pack("<I", api_version))
result.api_version = api_version
if isinstance(result, rdfvalue.RDFValue):
# Store the number of messages contained.
result.num_messages = len(message_list)
return timestamp
def DecodeMessages(self, response_comms):
"""Extract and verify server message.
Args:
response_comms: A ClientCommunication rdfvalue
Returns:
list of messages and the CN where they came from.
Raises:
DecryptionError: If the message failed to decrypt properly.
"""
if response_comms.api_version not in [3]:
raise DecryptionError("Unsupported api version: %s, expected 3." %
response_comms.api_version)
if response_comms.encrypted_cipher:
# Have we seen this cipher before?
try:
cipher = self.encrypted_cipher_cache.Get(
response_comms.encrypted_cipher)
except KeyError:
cipher = ReceivedCipher(response_comms, self.private_key,
self.pub_key_cache)
if cipher.signature_verified:
# Remember it for next time.
self.encrypted_cipher_cache.Put(
response_comms.encrypted_cipher, cipher)
# Verify the cipher HMAC with the new response_comms. This will raise
# DecryptionError if the HMAC does not agree.
cipher.VerifyHMAC(response_comms)
# Decrypt the message with the per packet IV.
plain = cipher.Decrypt(response_comms.encrypted,
response_comms.packet_iv)
try:
signed_message_list = rdfvalue.SignedMessageList(plain)
except rdfvalue.DecodeError as e:
raise DecryptionError(str(e))
message_list = self.DecompressMessageList(signed_message_list)
else:
# The message is not encrypted. We do not allow unencrypted
# messages:
raise DecryptionError("Server response is not encrypted.")
# Are these messages authenticated?
auth_state = self.VerifyMessageSignature(response_comms,
signed_message_list, cipher,
response_comms.api_version)
# Mark messages as authenticated and where they came from.
for msg in message_list.job:
msg.auth_state = auth_state
msg.SetWireFormat(
"source",
utils.SmartStr(cipher.cipher_metadata.source.Basename()))
return (message_list.job, cipher.cipher_metadata.source,
signed_message_list.timestamp)
def DecodeMessages(self, response_comms):
"""Extract and verify server message.
Args:
response_comms: A ClientCommunication rdfvalue
Returns:
list of messages and the CN where they came from.
Raises:
DecryptionError: If the message failed to decrypt properly.
"""
if response_comms.api_version not in [3]:
raise DecryptionError("Unsupported api version.")
if response_comms.encrypted_cipher:
# Have we seen this cipher before?
try:
cipher = self.encrypted_cipher_cache.Get(
response_comms.encrypted_cipher)
except KeyError:
cipher = ReceivedCipher(response_comms, self.private_key,
self.pub_key_cache)
if cipher.signature_verified:
# Remember it for next time.
self.encrypted_cipher_cache.Put(
response_comms.encrypted_cipher, cipher)
# Add entropy to the PRNG.
Rand.rand_add(response_comms.encrypted,
len(response_comms.encrypted))
# Check the encrypted message integrity using HMAC.
if cipher.HMAC(response_comms.encrypted) != response_comms.hmac:
raise DecryptionError("HMAC verification failed.")
# Decrypt the messages
iv = response_comms.iv or cipher.cipher.iv
plain = cipher.Decrypt(response_comms.encrypted, iv)
try:
signed_message_list = rdfvalue.SignedMessageList(plain)
except rdfvalue.DecodeError as e:
raise DecryptionError(str(e))
message_list = self.DecompressMessageList(signed_message_list)
else:
# The message is not encrypted. We do not allow unencrypted
# messages:
raise DecryptionError("Server response is not encrypted.")
# Are these messages authenticated?
auth_state = self.VerifyMessageSignature(response_comms,
signed_message_list, cipher,
response_comms.api_version)
# Mark messages as authenticated and where they came from.
for msg in message_list.job:
msg.auth_state = auth_state
msg.SetWireFormat(
"source",
utils.SmartStr(cipher.cipher_metadata.source.Basename()))
return (message_list.job, cipher.cipher_metadata.source,
signed_message_list.timestamp)