Windows support + Overlapping Segmentation

.travis.yml

@@ -32,7 +32,7 @@ install:
     # Copy in the sudoers file
     - sudo cp /tmp/sudoers.tmp /etc/sudoers 
     # Now that sudo is good to go, finish installing dependencies
-    - sudo python3 -m pip install -r requirements.txt
+    - sudo python3 -m pip install -r requirements_linux.txt
     - sudo python3 -m pip install slackclient pytest-cov
 
 script:

README.md

@@ -8,17 +8,21 @@ This code release specifically contains the strategy engine used by Geneva, its
 
 ## Setup
 
-Geneva has been developed and tested for Centos or Debian-based systems. Due to limitations of
-netfilter and raw sockets, Geneva does not work on OS X or Windows at this time and requires *python3.6* (with more versions coming soon).
+Geneva has been developed and tested for Centos or Debian-based systems. Windows support is currently in beta and requires more testing, but is available in this repository. Due to limitations of netfilter and raw sockets, Geneva does not work on OS X at this time and requires *python3.6* on Linux (with more versions coming soon).
 
-Install netfilterqueue dependencies:
+Install netfilterqueue dependencies (Linux):
 ```
 # sudo apt-get install build-essential python-dev libnetfilter-queue-dev libffi-dev libssl-dev iptables python3-pip
 ```
 
-Install Python dependencies:
+Install Python dependencies (Linux):
 ```
-# python3 -m pip install -r requirements.txt
+# python3 -m pip install -r requirements_linux.txt
+```
+
+Install Python dependencies (Windows):
+```
+# python3 -m pip install -r requirements_windows.txt
 ```
 
 ## Running it

actions/fragment.py

@@ -6,7 +6,7 @@
 
 
 class FragmentAction(Action):
-    def __init__(self, environment_id=None, correct_order=None, fragsize=-1, segment=True):
+    def __init__(self, environment_id=None, correct_order=None, fragsize=-1, segment=True, overlap=0):
         '''
         correct_order specifies if the fragmented packets should come in the correct order
         fragsize specifies how
@@ -17,6 +17,7 @@ def __init__(self, environment_id=None, correct_order=None, fragsize=-1, segment
         self.terminal = False
         self.fragsize = fragsize
         self.segment = segment
+        self.overlap = overlap
 
         if correct_order == None:
             self.correct_order = self.get_rand_order()
@@ -87,6 +88,9 @@ def tcp_segment(self, packet, logger):
         Segments a packet into two, given the size of the first packet (0:fragsize)
         Always returns two packets, since fragment is a branching action, so if we
         are unable to segment, it will duplicate the packet.
+
+        If overlap is specified, it will select n bytes from the second packet 
+        and append them to the first, and increment the sequence number accordingly
         """
         if not packet.haslayer("TCP") or not hasattr(packet["TCP"], "load") or not packet["TCP"].load:
             return packet, packet.copy() # duplicate if no TCP or no payload to segment
@@ -101,7 +105,11 @@ def tcp_segment(self, packet, logger):
             fragsize = int(len(payload)/2)
 
         # Craft new packets
-        pkt1 = IP(packet["IP"])/payload[:fragsize]
+
+        # Make sure we don't go out of bounds by choosing the min
+        overlapBytes = min(len(payload[fragsize:]), self.overlap)
+        # Attach these bytes to the first packet
+        pkt1 = IP(packet["IP"])/payload[:fragsize + overlapBytes]
         pkt2 = IP(packet["IP"])/payload[fragsize:]
 
         # We cannot rely on scapy's native parsing here - if a previous action has changed the
@@ -147,10 +155,15 @@ def __str__(self):
         Returns a string representation with the fragsize
         """
         s = Action.__str__(self)
+        if self.overlap == 0:
+            ending = "}"
+        else:
+            ending = ":" + str(self.overlap) + "}"
+
         if self.segment:
-            s += "{" + "tcp" + ":" + str(self.fragsize)  + ":" + str(self.correct_order) + "}"
+            s += "{" + "tcp" + ":" + str(self.fragsize)  + ":" + str(self.correct_order) + ending
         else:
-            s += "{" + "ip" + ":"+ str(self.fragsize)  + ":" + str(self.correct_order) + "}"
+            s += "{" + "ip" + ":"+ str(self.fragsize)  + ":" + str(self.correct_order) + ending
         return s
 
     def parse(self, string, logger):
@@ -169,22 +182,36 @@ def parse(self, string, logger):
         num_parameters = string.count(":")
 
         # If num_parameters is greater than 2, it's not a valid fragment action
-        if num_parameters != 2:
-            msg = "Cannot parse fragment action %s" % string
-            logger.error(msg)
-            raise Exception(msg)
-        else:
+        if num_parameters == 2:
             params = string.split(":")
             seg, fragsize, correct_order = params
+            overlap = 0
+            if "tcp" in seg:
+                self.segment = True
+            else:
+                self.segment = False
+
+        elif num_parameters == 3:
+            params = string.split(":")
+            seg, fragsize, correct_order, overlap = params
+            if overlap.endswith("}"):
+                overlap = overlap[:-1] # Chop off trailing }
             if "tcp" in seg:
                 self.segment = True
             else:
                 self.segment = False
+
+        else:
+            msg = "Cannot parse fragment action %s" % string
+            logger.error(msg)
+            raise Exception(msg)
 
         try:
             # Try to convert to int
             self.fragsize = int(fragsize)
-        except ValueError:
+            self.overlap = int(overlap)
+        except ValueError as e:
+            print(e)
             msg = "Cannot parse fragment action %s" % string
             logger.error(msg)
             raise Exception(msg)

actions/utils.py

@@ -181,11 +181,15 @@ def get_interface():
     """
     Chooses an interface on the machine to use for socket testing.
     """
-    ifaces = netifaces.interfaces()
-    for iface in ifaces:
-        if "lo" in iface:
-            continue
-        info = netifaces.ifaddresses(iface)
-        # Filter for IPv4 addresses
-        if netifaces.AF_INET in info:
-            return iface
+    if os.name == 'nt':
+        # Windows code
+        return # TODO: Fix this 
+    else:
+        ifaces = netifaces.interfaces()
+        for iface in ifaces:
+            if "lo" in iface:
+                continue
+            info = netifaces.ifaddresses(iface)
+            # Filter for IPv4 addresses
+            if netifaces.AF_INET in info:
+                return iface