private IP range checks

When advertising nodes and when establishing connections, private IP
range checks were not done. This could cause private IPs to be
advertised across the network. Also, some of the checks weren't
IPv6-aware.
Fixes Bitmessage#768

src/class_receiveDataThread.py

@@ -490,9 +490,19 @@ class receiveDataThread(threading.Thread):
         logger.debug('sending an object.')
         self.sendDataThreadQueue.put((0, 'sendRawData', shared.CreatePacket('object',payload)))
 
+    def _checkIPAddress(self, host):
+        if host[0:12] == '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF':
+            hostStandardFormat = socket.inet_ntop(socket.AF_INET, host[12:])
+            return self._checkIPv4Address(host[12:], hostStandardFormat)
+        else:
+            hostStandardFormat = socket.inet_ntop(socket.AF_INET6, host)
+            if hostStandardFormat == "":
+                # This can happen on Windows systems which are not 64-bit compatible 
+                # so let us drop the IPv6 address. 
+                return False
+            return self._checkIPv6Address(host, hostStandardFormat)
 
     def _checkIPv4Address(self, host, hostStandardFormat):
-        # print 'hostStandardFormat', hostStandardFormat
         if host[0] == '\x7F': # 127/8
             logger.debug('Ignoring IP address in loopback range: ' + hostStandardFormat)
             return False
@@ -505,7 +515,7 @@ class receiveDataThread(threading.Thread):
         if host[0:2] >= '\xAC\x10' and host[0:2] < '\xAC\x20': # 172.16/12
             logger.debug('Ignoring IP address in private range:' + hostStandardFormat)
             return False
-        return True
+        return hostStandardFormat
 
     def _checkIPv6Address(self, host, hostStandardFormat):
         if host == ('\x00' * 15) + '\x01':
@@ -517,7 +527,7 @@ class receiveDataThread(threading.Thread):
         if (ord(host[0]) & 0xfe) == 0xfc:
             logger.debug ('Ignoring unique local address: ' + hostStandardFormat)
             return False
-        return True
+        return hostStandardFormat
 
     # We have received an addr message.
     def recaddr(self, data):
@@ -545,18 +555,8 @@ class receiveDataThread(threading.Thread):
                 38 * i):20 + lengthOfNumberOfAddresses + (38 * i)])
             recaddrPort, = unpack('>H', data[36 + lengthOfNumberOfAddresses + (
                 38 * i):38 + lengthOfNumberOfAddresses + (38 * i)])
-            if fullHost[0:12] == '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xFF\xFF':
-                ipv4Host = fullHost[12:]
-                hostStandardFormat = socket.inet_ntop(socket.AF_INET, ipv4Host)
-                if not self._checkIPv4Address(ipv4Host, hostStandardFormat):
-                    continue
-            else:
-                hostStandardFormat = socket.inet_ntop(socket.AF_INET6, fullHost)
-                if hostStandardFormat == "":
-                    # This can happen on Windows systems which are not 64-bit compatible 
-                    # so let us drop the IPv6 address. 
-                    continue
-                if not self._checkIPv6Address(fullHost, hostStandardFormat):
+            hostStandardFormat = self._checkIPAddress(fullHost)
+            if hostStandardFormat is False:
                 continue
             timeSomeoneElseReceivedMessageFromThisNode, = unpack('>Q', data[lengthOfNumberOfAddresses + (
                 38 * i):8 + lengthOfNumberOfAddresses + (38 * i)])  # This is the 'time' value in the received addr message. 64-bit.
@@ -744,6 +744,7 @@ class receiveDataThread(threading.Thread):
         # in this version message. Let us inform the sendDataThread.
         self.sendDataThreadQueue.put((0, 'setRemoteProtocolVersion', self.remoteProtocolVersion))
 
+        if not isHostInPrivateIPRange(self.peer.host):
             with shared.knownNodesLock:
                 shared.knownNodes[self.streamNumber][shared.Peer(self.peer.host, self.remoteNodeIncomingPort)] = int(time.time())
                 shared.needToWriteKnownNodesToDisk = True

src/helper_generic.py

@@ -1,6 +1,8 @@
-import shared
+import socket
 import sys
 
+import shared
+
 def convertIntToString(n):
     a = __builtins__.hex(n)
     if a[-1:] == 'L':
@@ -23,6 +25,16 @@ def signal_handler(signal, frame):
         print 'Unfortunately you cannot use Ctrl+C when running the UI because the UI captures the signal.'
 
 def isHostInPrivateIPRange(host):
+    if ":" in host: #IPv6
+        hostAddr = socket.inet_pton(socket.AF_INET6, host)
+        if hostAddr == ('\x00' * 15) + '\x01':
+            return False
+        if hostAddr[0] == '\xFE' and (ord(hostAddr[1]) & 0xc0) == 0x80:
+            return False
+        if (ord(hostAddr[0]) & 0xfe) == 0xfc:
+            return False
+        pass
+    else:
         if host[:3] == '10.':
             return True
         if host[:4] == '172.':