spacefreak/uvscand
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Fix protocol handling

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This commit is contained in:
Thomas Oettli
2020-03-09 18:06:34 +01:00
parent 693d7ac3e1
commit f9e0929a56
2 changed files with 71 additions and 49 deletions
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2
setup.py
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@@ -5,7 +5,7 @@ def read_file(fname):
return f.read()
setup(name = "uvscand",
version = "0.0.3",
version = "0.0.4",
author = "Thomas Oettli",
author_email = "spacefreak@noop.ch",
description = "A python daemon to perform virus scans with uvscan (McAfee) over TCP socket.",

96
uvscand/__init__.py
View File

@@ -53,7 +53,6 @@ class AIO(asyncio.Protocol):
config = None
queue = asyncio.Queue()
separator = b"\x00"
completed = False
def __init__(self):
if not AIO.config:
@@ -61,67 +60,89 @@ class AIO(asyncio.Protocol):
if not AIO.queue:
raise RuntimeError("queue not set")
self.logger = logging.getLogger(__name__)
self.data = bytearray()
self.tmpfile = None
def _send_response(self, response):
response = response.encode() + AIO.separator
self.logger.debug("{} sending response: {}".format(self.peer, response))
self.transport.write(response)
self.transport.close()
def connection_made(self, transport):
self.peer = transport.get_extra_info("peername")
self.logger.info("new connection from {}".format(self.peer))
self.transport = transport
self.request_time = str(time.time())
self.buffer = bytearray()
self.data = bytearray()
self.command = None
self.length = None
self.all_chunks = False
self.completed = False
def data_received(self, data):
self.logger.debug("data received from {}".format(self.peer))
self.data.extend(data)
if self.data[-4:] == b"\x00\x00\x00\x00":
self.logger.debug("last data chunk received from {}".format(self.peer))
self.process_request()
else:
self.logger.debug("received data chunk from {}".format(self.peer))
def process_request(self):
try:
if self.data[0] != ord(b"z"):
if self.all_chunks:
self.logger.warning("{} received {} bytes of garbage after last chunk".format(self.peer, len(data)))
return
self.logger.debug("{} received {} bytes".format(self.peer, len(data)))
self.buffer.extend(data)
if not self.command:
if len(self.buffer) < 10:
return
if self.buffer[0] != ord(b"z"):
raise RuntimeError("protocol error")
pos = self.data.index(ord(AIO.separator))
pos = self.buffer.index(ord(AIO.separator))
# parse command
command = self.data[0:pos].decode()
command = self.buffer[0:pos].decode()
if command != "zINSTREAM":
raise RuntimeError("unknown command")
self.command = command
self.logger.debug("{} command is {}".format(self.peer, command))
pos += 1
if command == "zINSTREAM":
# save data chunks to temporary file
self.buffer = self.buffer[pos:]
if self.command:
while True:
if not self.length:
if len(self.buffer) < 4:
break
self.length = struct.unpack(">I", self.buffer[0:4])[0]
self.buffer = self.buffer[4:]
if self.length == 0:
self.all_chunks = True
tmpfile = os.path.join(AIO.config["tmpdir"], "uvscan_{}_{}".format(self.request_time, str(self.peer[1])))
self.logger.debug("save data from {} in temporary file {}".format(self.peer, tmpfile))
self.logger.debug("{} got last chunk, save data to {}".format(self.peer, tmpfile))
with open(tmpfile, "wb") as f:
self.tmpfile = tmpfile
while True:
length = struct.unpack(">I", self.data[pos:pos + 4])[0]
if length == 0: break
pos += 4
f.write(self.data[pos:pos + length])
pos += length
f.write(self.data)
AIO.queue.put_nowait((AIO.config["uvscan_path"], tmpfile, self.process_uvscan_result))
self.logger.info("queued uvscan of {}, queue size is {}".format(tmpfile, AIO.queue.qsize()))
self.logger.info("{} queued uvscan of {}, queue size is {}".format(self.peer, tmpfile, AIO.queue.qsize()))
break
self.logger.debug("{} got chunk size of {} bytes".format(self.peer, self.length))
else:
raise RuntimeError("unknown command")
except (RuntimeError, IndexError, IOError, struct.error) as e:
self.logger.warning("warning: {}".format(e))
self.send_response(str(e))
if len(self.buffer) < self.length:
self.logger.debug("{} got {} of {} bytes".format(self.peer, len(self.buffer), self.length))
break
self.logger.debug("{} chunk complete ({} bytes)".format(self.peer, self.length))
self.data.extend(self.buffer[0:self.length])
self.buffer = self.buffer[self.length:]
self.length = None
def send_response(self, response):
response = response.encode() + AIO.separator
self.logger.debug("sending response to {}: {}".format(self.peer, response))
self.transport.write(response)
self.transport.close()
except (RuntimeError, IndexError, IOError, struct.error) as e:
self.logger.warning("{} warning: {}".format(self.peer, e))
self._send_response(str(e))
def process_uvscan_result(self, result):
self.logger.info("received uvscan result of {}: {}".format(self.tmpfile, result))
self.logger.info("{} received uvscan result of {}: {}".format(self.peer, self.tmpfile, result))
self.completed = True
self.send_response(result)
self._send_response(result)
def connection_lost(self, exc):
if self.tmpfile:
if not self.completed:
self.logger.warning("client prematurely closed connection, removing {} from scan queue".format(self.tmpfile))
self.logger.warning("{} client prematurely closed connection, removing {} from scan queue".format(self.peer, self.tmpfile))
entries = []
try:
for entry in iter(AIO.queue.get_nowait, None):
@@ -133,7 +154,7 @@ class AIO(asyncio.Protocol):
pass
for entry in entries:
AIO.queue.put_nowait(entry)
self.logger.debug("removing temporary file {}".format(self.tmpfile))
self.logger.debug("{} removing temporary file {}".format(self.peer, self.tmpfile))
os.remove(self.tmpfile)
self.logger.info("closed connection to {}".format(self.peer))
@@ -192,6 +213,7 @@ def main():
logger.error("option '{}' not present in config section 'uvscand'".format(option))
sys.exit(1)
if not args.debug:
# set loglevel according to config
stdouthandler.setLevel(int(config["loglevel"]))
sysloghandler.setLevel(int(config["loglevel"]))