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inline handshake parsing and explain MAX_LENGTH for transit server

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This commit is contained in:
Joe Harrison 2020-03-08 19:54:42 +00:00
parent 4fdd89cb35
commit 8f89c8aaff
1 changed files with 14 additions and 28 deletions
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42
src/wormhole_transit_relay/transit_server.py
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@ -26,7 +26,11 @@ def blur_size(size):
class TransitConnection(LineReceiver): class TransitConnection(LineReceiver):
delimiter = b'\n' delimiter = b'\n'
# maximum length of a line we will accept before the handshake is complete.
# This must be >= to the longest possible handshake message.
MAX_LENGTH = 1024
def __init__(self): def __init__(self):
self._got_token = False self._got_token = False
self._got_side = False self._got_side = False
@ -51,14 +55,17 @@ class TransitConnection(LineReceiver):
self.transport.setTcpKeepAlive(True) self.transport.setTcpKeepAlive(True)
def lineReceived(self, line): def lineReceived(self, line):
old = self._check_old_handshake(line) # old: "please relay {64}\n"
if old is not None: old = re.fullmatch(br"please relay (\w{64})", line)
token = old if old:
token = old.group(1)
return self._got_handshake(token, None) return self._got_handshake(token, None)
new = self._check_new_handshake(line) # new: "please relay {64} for side {16}\n"
if new is not None: new = re.fullmatch(br"please relay (\w{64}) for side (\w{16})", line)
token, side = new if new:
token = new.group(1)
side = new.group(2)
return self._got_handshake(token, side) return self._got_handshake(token, side)
self.sendLine(b"bad handshake") self.sendLine(b"bad handshake")
@ -76,27 +83,6 @@ class TransitConnection(LineReceiver):
if self._log_requests: if self._log_requests:
log.msg("transit impatience failure") log.msg("transit impatience failure")
def _check_old_handshake(self, buf):
# old: "please relay {64}\n"
# return token if buf contains an old-style handshake
# return None if buf does not contain one
mo = re.search(br"^please relay (\w{64})$", buf, re.M)
if mo:
token = mo.group(1)
return token
return None
def _check_new_handshake(self, buf):
# new: "please relay {64} for side {16}\n"
# return (token, side) if but contains a new-style handshake
# return None if buf does not contain one
mo = re.search(br"^please relay (\w{64}) for side (\w{16})$", buf, re.M)
if mo:
token = mo.group(1)
side = mo.group(2)
return (token, side)
return None
def _got_handshake(self, token, side): def _got_handshake(self, token, side):
self._got_token = token self._got_token = token
self._got_side = side self._got_side = side