Onionr/src/onionrutils/validatemetadata.py

128 lines
5.5 KiB
Python

"""Onionr - Private P2P Communication.
validate new block's metadata
"""
from json import JSONDecodeError
import ujson as json
import logger, onionrexceptions
from etc import onionrvalues
from . import stringvalidators, epoch, bytesconverter
import config, filepaths, onionrcrypto
"""
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
def validate_metadata(metadata, block_data) -> bool:
"""Validate metadata meets onionr spec (does not validate proof value computation), take in either dictionary or json string"""
ret_data = False
max_clock_difference = onionrvalues.MAX_BLOCK_CLOCK_SKEW
# convert to dict if it is json string
if type(metadata) is str:
try:
metadata = json.loads(metadata)
except JSONDecodeError:
pass
# Validate metadata dict for invalid keys to sizes that are too large
maxAge = onionrvalues.DEFAULT_EXPIRE
if type(metadata) is dict:
for i in metadata:
try:
onionrvalues.BLOCK_METADATA_LENGTHS[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 onionrvalues.BLOCK_METADATA_LENGTHS[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] - epoch.get_epoch())
if isFuture > max_clock_difference:
logger.warn('Block timestamp is skewed to the future over the max %s: %s', (max_clock_difference, isFuture))
break
if (epoch.get_epoch() - metadata[i]) > maxAge:
logger.warn('Block is outdated: %s' % (metadata[i],))
break
elif i == 'expire':
try:
if not int(metadata[i]) > epoch.get_epoch(): raise ValueError
except ValueError:
logger.warn('Block is expired: %s less than %s' % (metadata[i], epoch.get_epoch()))
break
elif i == 'encryptType':
try:
if not metadata[i] in ('asym', 'sym', ''): raise ValueError
except ValueError:
logger.warn('Invalid encryption mode')
break
elif i == 'sig':
try:
metadata['encryptType']
except KeyError:
signer = metadata['signer']
sig = metadata['sig']
encodedMeta = bytesconverter.str_to_bytes(metadata['meta'])
encodedBlock = bytesconverter.str_to_bytes(block_data)
if not onionrcrypto.signing.ed_verify(encodedMeta + encodedBlock[1:], signer, sig):
logger.warn(f'Block was signed by {signer}, but signature failed')
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)
# Make sure time is set (validity was checked above if it is)
if not config.get('general.store_plaintext_blocks', True):
try:
if not metadata['encryptType']:
raise onionrexceptions.PlaintextNotSupported
except KeyError:
raise onionrexceptions.PlaintextNotSupported
try:
metadata['time']
except KeyError:
logger.warn("Time header not set")
return False
nonce = bytesconverter.bytes_to_str(onionrcrypto.hashers.sha3_hash(block_data))
try:
with open(filepaths.data_nonce_file, 'r') as nonceFile:
if nonce in nonceFile.read():
# we've seen that nonce before, so we can't pass metadata
raise onionrexceptions.DataExists
except FileNotFoundError:
ret_data = True
except onionrexceptions.DataExists:
# do not set ret_data to True, because data has been seen before
logger.warn(f'{nonce} seen before')
raise onionrexceptions.DataExists
else:
ret_data = True
else:
logger.warn('In call to utils.validateMetadata, metadata must be JSON string or a dictionary object')
return ret_data