Onionr/onionr/onionrutils/validatemetadata.py
2019-06-25 03:21:36 -05:00

78 lines
3.5 KiB
Python

import json
import logger, onionrexceptions
from etc import onionrvalues
from onionrutils import stringvalidators
def validate_metadata(core_inst, metadata, blockData):
'''Validate metadata meets onionr spec (does not validate proof value computation), take in either dictionary or json string'''
# TODO, make this check sane sizes
retData = False
maxClockDifference = 120
# convert to dict if it is json string
if type(metadata) is str:
try:
metadata = json.loads(metadata)
except json.JSONDecodeError:
pass
# Validate metadata dict for invalid keys to sizes that are too large
maxAge = core_inst.config.get("general.max_block_age", onionrvalues.OnionrValues().default_expire)
if type(metadata) is dict:
for i in metadata:
try:
core_inst.requirements.blockMetadataLengths[i]
except KeyError:
logger.warn('Block has invalid metadata key ' + i)
break
else:
testData = metadata[i]
try:
testData = len(testData)
except (TypeError, AttributeError) as e:
testData = len(str(testData))
if core_inst.requirements.blockMetadataLengths[i] < testData:
logger.warn('Block metadata key ' + i + ' exceeded maximum size')
break
if i == 'time':
if not stringvalidators.is_integer_string(metadata[i]):
logger.warn('Block metadata time stamp is not integer string or int')
break
isFuture = (metadata[i] - core_inst.getEpoch())
if isFuture > maxClockDifference:
logger.warn('Block timestamp is skewed to the future over the max %s: %s' (maxClockDifference, isFuture))
break
if (core_inst.getEpoch() - metadata[i]) > maxAge:
logger.warn('Block is outdated: %s' % (metadata[i],))
break
elif i == 'expire':
try:
assert int(metadata[i]) > core_inst.getEpoch()
except AssertionError:
logger.warn('Block is expired: %s less than %s' % (metadata[i], core_inst.getEpoch()))
break
elif i == 'encryptType':
try:
assert metadata[i] in ('asym', 'sym', '')
except AssertionError:
logger.warn('Invalid encryption mode')
break
else:
# if metadata loop gets no errors, it does not break, therefore metadata is valid
# make sure we do not have another block with the same data content (prevent data duplication and replay attacks)
nonce = core_inst._utils.bytesToStr(core_inst._crypto.sha3Hash(blockData))
try:
with open(core_inst.dataNonceFile, 'r') as nonceFile:
if nonce in nonceFile.read():
retData = False # we've seen that nonce before, so we can't pass metadata
raise onionrexceptions.DataExists
except FileNotFoundError:
retData = True
except onionrexceptions.DataExists:
# do not set retData to True, because nonce has been seen before
pass
else:
retData = True
else:
logger.warn('In call to utils.validateMetadata, metadata must be JSON string or a dictionary object')
return retData