Fix two issues related to handleHello

In some circumstances, the hello_protocol attribute could get modified
on the wrong peer, which would raise an AttributeError.
On reception of seqno 1 from a peer with protocol < 7, protocol could be
equal to zero which would cause handleHello to not return True, causing
the handshake to fail.

re6st/tunnel.py

@@ -384,14 +384,14 @@ class BaseTunnelManager(object):
         peer = self._getPeer(prefix)
         msg = peer.decode(msg)
         if type(msg) is tuple:
-          real_seqno, msg = msg
-          def handleHello(peer, seqno, msg):
+          seqno, msg, protocol = msg
+          def handleHello(peer, seqno, msg, retry):
             if seqno == 2:
                 i = len(msg) // 2
                 h = msg[:i]
                 try:
                     peer.verify(msg[i:], h)
-                    peer.newSession(self.cert.decrypt(h))
+                    peer.newSession(self.cert.decrypt(h), protocol)
                 except (AttributeError, crypto.Error, x509.NewSessionError,
                         subprocess.CalledProcessError):
                     logging.debug('ignored new session key from %r',
@@ -412,7 +412,7 @@ class BaseTunnelManager(object):
                 if serial in self.cache.crl:
                     raise ValueError("revoked")
             except (x509.VerifyError, ValueError), e:
-                if real_seqno and peer.hello_protocol:
+                if retry:
                     return True
                 logging.debug('ignored invalid certificate from %r (%s)',
                               address, e.args[-1])
@@ -430,17 +430,17 @@ class BaseTunnelManager(object):
             peer.stop_date = stop_date
             self.selectTimeout(stop_date, self.invalidatePeers, False)
             if seqno:
-                self._sendto(to, peer.hello(self.cert))
+                self._sendto(to, peer.hello(self.cert, protocol))
             else:
                 msg = peer.hello0(self.cert.cert)
                 if msg and self._sendto(to, msg):
                     peer.hello0Sent()
-          if handleHello(peer, real_seqno, msg):
+          if handleHello(peer, seqno, msg, seqno):
             # It is possible to reconstruct the original message because
             # the serialization of the protocol version is always unique.
-            msg = utils.packInteger(peer.hello_protocol) + msg
-            peer.hello_protocol = 0
-            handleHello(peer, real_seqno, msg)
+            msg = utils.packInteger(protocol) + msg
+            protocol = 0
+            handleHello(peer, seqno, msg, False)
         elif msg:
             # We got a valid and non-empty message. Always reply
             # something so that the sender knows we're still connected.

re6st/x509.py

@@ -241,26 +241,26 @@ class Peer(object):
     def hello0Sent(self):
         self._hello = time.time() + 60
 
-    def hello(self, cert):
+    def hello(self, cert, protocol):
         key = self._key = newHmacSecret()
         h = encrypt(crypto.dump_certificate(crypto.FILETYPE_PEM, self.cert),
                     key)
         self._i = self._j = 2
         self._last = 0
-        self.protocol = self.hello_protocol
-        return ''.join(('\0\0\0\2', PACKED_PROTOCOL if self.protocol else '',
+        self.protocol = protocol
+        return ''.join(('\0\0\0\2', PACKED_PROTOCOL if protocol else '',
                         h, cert.sign(h)))
 
     def _hmac(self, msg):
         return hmac.HMAC(self._key, msg, hashlib.sha1).digest()
 
-    def newSession(self, key):
+    def newSession(self, key, protocol):
         if key <= self._key:
             raise NewSessionError(self._key, key)
         self._key = key
         self._i = self._j = 2
         self._last = None
-        self.protocol = self.hello_protocol
+        self.protocol = protocol
 
     def verify(self, sign, data):
         crypto.verify(self.cert, sign, data, 'sha512')
@@ -272,9 +272,11 @@ class Peer(object):
         if seqno <= 2:
             msg = msg[4:]
             if seqno:
-                self.hello_protocol, n = utils.unpackInteger(msg) or (0, 0)
+                protocol, n = utils.unpackInteger(msg) or (0, 0)
                 msg = msg[n:]
-            return seqno, msg
+            else:
+                protocol = None
+            return seqno, msg, protocol
         i = -utils.HMAC_LEN
         if self._hmac(msg[:i]) == msg[i:] and self._i < seqno:
             self._last = None