Decompression limit

- there is now a configurable decompression limit, default at
1MB. Oversize messages are trated as if they never arrived,
just a log entry
This commit is contained in:
Peter Šurda 2017-05-15 12:23:16 +02:00
parent 9f4a1fa0a4
commit 183f509f09
Signed by: PeterSurda
GPG Key ID: 0C5F50C0B5F37D87
2 changed files with 24 additions and 5 deletions

View File

@ -28,7 +28,6 @@ import tr
from debug import logger
import l10n
class objectProcessor(threading.Thread):
"""
The objectProcessor thread, of which there is only one, receives network
@ -71,6 +70,8 @@ class objectProcessor(threading.Thread):
pass
else:
logger.critical('Error! Bug! The class_objectProcessor was passed an object type it doesn\'t recognize: %s' % str(objectType))
except helper_msgcoding.DecompressionSizeException as e:
logger.error("The object is too big after decompression (stopped decompressing at %ib, your configured limit %ib). Ignoring", e.size, BMConfigParser().safeGetInt("zlib", "maxsize"))
except varintDecodeError as e:
logger.debug("There was a problem with a varint while processing an object. Some details: %s" % e)
except Exception as e:

View File

@ -7,6 +7,7 @@ except ImportError:
import string
import zlib
from bmconfigparser import BMConfigParser
import shared
from debug import logger
import messagetypes
@ -17,6 +18,10 @@ BITMESSAGE_ENCODING_TRIVIAL = 1
BITMESSAGE_ENCODING_SIMPLE = 2
BITMESSAGE_ENCODING_EXTENDED = 3
class DecompressionSizeException(Exception):
def __init__(self, size):
self.size = size
class MsgEncode(object):
def __init__(self, message, encoding=BITMESSAGE_ENCODING_SIMPLE):
@ -65,11 +70,24 @@ class MsgDecode(object):
self.subject = _translate("MsgDecode", "Unknown encoding")
def decodeExtended(self, data):
dc = zlib.decompressobj()
tmp = ""
while len(tmp) <= BMConfigParser().safeGetInt("zlib", "maxsize"):
try:
got = dc.decompress(data, BMConfigParser().safeGetInt("zlib", "maxsize") + 1 - len(tmp))
# EOF
if got == "":
break
tmp += got
data = dc.unconsumed_tail
except zlib.error:
logger.error("Error decompressing message")
raise
else:
raise DecompressionSizeException(len(tmp))
try:
tmp = msgpack.loads(zlib.decompress(data))
except zlib.error:
logger.error("Error decompressing message")
raise
tmp = msgpack.loads(tmp)
except (msgpack.exceptions.UnpackException,
msgpack.exceptions.ExtraData):
logger.error("Error msgunpacking message")