Use iptables trough iptc, enables rootless operation

Reviving my PR #41 and
polishing it up a bit for easier usage

bin/opensnitch → opensnitch/__main__.py

@@ -22,7 +22,6 @@
 import warnings
 import logging
 import os
-import sys
 
 from opensnitch.version import VERSION
 from opensnitch.snitch import Snitch
@@ -45,9 +44,6 @@
 
 args = parser.parse_args()
 
-if not os.geteuid() == 0:
-    sys.exit('OpenSnitch must be run as root.')
-
 
 # Ensure Qt4 wont be loaded by matplotlib
 try:

opensnitch/iptables.py

@@ -0,0 +1,74 @@
+import iptc
+
+
+class IPTCRules:
+
+    def __init__(self):
+        self.tables = {
+            iptc.Table.FILTER: iptc.Table(iptc.Table.FILTER),
+            iptc.Table.MANGLE: iptc.Table(iptc.Table.MANGLE),
+        }
+        for t in self.tables.values():
+            t.autocommit = False
+
+        self.chains = {
+            c: r for c, r in (
+                self.insert_dns_rule(),
+                self.insert_connection_packet_rules(),
+                self.insert_reject_rule())
+        }
+
+        self.commit()
+
+    def commit(self):
+        for t in self.tables.values():
+            t.commit()
+            t.refresh()
+
+    def remove(self):
+        for c, r in self.chains.items():
+            c.delete_rule(r)
+
+        self.commit()
+
+    def insert_dns_rule(self):
+        """Get DNS responses"""
+        chain = iptc.Chain(self.tables[iptc.Table.FILTER], 'INPUT')
+        rule = iptc.Rule()
+        rule.protocol = 'udp'
+        m = rule.create_match('udp')
+        m.sport = '53'
+
+        t = rule.create_target('NFQUEUE')
+        t.set_parameter('queue-num', str(0))
+        t.set_parameter('queue-bypass')
+
+        chain.insert_rule(rule)
+        return (chain, rule)
+
+    def insert_connection_packet_rules(self):
+        chain = iptc.Chain(self.tables[iptc.Table.MANGLE], 'OUTPUT')
+        rule = iptc.Rule()
+
+        t = rule.create_target('NFQUEUE')
+        t.set_parameter('queue-num', str(0))
+        t.set_parameter('queue-bypass')
+
+        m = rule.create_match('conntrack')
+        m.set_parameter('ctstate', 'NEW')
+
+        chain.insert_rule(rule)
+        return (chain, rule)
+
+    def insert_reject_rule(self):
+        chain = iptc.Chain(self.tables[iptc.Table.FILTER], 'OUTPUT')
+        rule = iptc.Rule()
+        rule.protol = 'tcp'
+
+        rule.create_target('REJECT')
+
+        m = rule.create_match('mark')
+        m.mark = '0x18ba5'
+
+        chain.insert_rule(rule)
+        return (chain, rule)

opensnitch/snitch.py

@@ -23,13 +23,13 @@
 import threading
 import logging
 import weakref
-import os
 
 from opensnitch.ui import QtApp
 from opensnitch.connection import Connection
 from opensnitch.dns import DNSCollector
 from opensnitch.rule import RuleVerdict, Rules
 from opensnitch.procmon import ProcMon
+from opensnitch.iptables import IPTCRules
 
 
 MARK_PACKET_DROP = 101285
@@ -103,19 +103,11 @@ def pkt_callback(self, pkt):
     def run(self):
         q = None
         try:
-            for r in IPTABLES_RULES:
-                logging.debug("Applying iptables rule '%s'", r)
-                os.system("iptables -I %s" % r)
-
             q = NetfilterQueue()
             q.bind(0, self.pkt_callback, 1024 * 2)
             q.run()
 
         finally:
-            for r in IPTABLES_RULES:
-                logging.debug("Deleting iptables rule '%s'", r)
-                os.system("iptables -D %s" % r)
-
             if q is not None:
                 q.unbind()
 
@@ -160,14 +152,19 @@ def __init__(self, database):
         self.dns = DNSCollector()
         self.q = NetfilterQueueWrapper(self)
         self.procmon = ProcMon()
+        self.iptcrules = None
         self.qt_app = QtApp(self.q.connection_futures, self.rules)
 
     def start(self):
         if ProcMon.is_ftrace_available():
             self.procmon.enable()
             self.procmon.start()
 
+        self.iptcrules = IPTCRules()
         self.qt_app.run()
 
     def stop(self):
+        if self.iptcrules is not None:
+            self.iptcrules.remove()
+
         self.procmon.disable()

setup.py

@@ -49,4 +49,6 @@
           'dpkt',
           'NetfilterQueue',
           'psutil',
-          'pyinotify'])
+          'pyinotify',
+          'python-iptables'
+      ])