Add documentation that explains what is going on with the new daemon.

.gitignore

@@ -1,4 +1,8 @@
+rpm/
+pkgs/
 *.pyc
+*.pyo
 *~
 *.tar.gz
 *.rpm
+.*.swp

Makefile.builder

@@ -0,0 +1,3 @@
+ifeq ($(PACKAGE_SET),dom0)
+RPM_SPEC_FILES=qubes-network-server.spec
+endif

qubes-network-server.spec

@@ -1,3 +1,5 @@
+%{!?python_sitearch: %define python_sitearch %(%{__python} -c "from distutils.sysconfig import get_python_lib; print get_python_lib(1)")}
+
 %define debug_package %{nil}
 
 %define mybuildnumber %{?build_number}%{?!build_number:1}
@@ -37,8 +39,8 @@ make install DESTDIR=$RPM_BUILD_ROOT BINDIR=%{_bindir} LIBDIR=%{_libdir}
 
 %files
 %attr(0755, root, root) %{_bindir}/qvm-static-ip
-%attr(0644, root, root) %{_libdir}/python2.7/site-packages/qubes/modules/*.py*
-%attr(0644, root, root) %{_libdir}/python2.7/site-packages/qubes/modules/qubes-appvm-firewall
+%attr(0644, root, root) %{python_sitearch}/qubes/modules/*.py*
+%attr(0644, root, root) %{python_sitearch}/qubes/modules/qubes-appvm-firewall
 %doc README.md TODO
 
 %changelog

src/usr/lib64/python2.7/site-packages/qubes/modules/007FortressQubesProxyVm.py

@@ -96,35 +96,45 @@ class QubesProxyVm(OriginalQubesProxyVm):
                 rules_action = accept_action
 
             for rule in conf["rules"]:
-                if getattr(vm, "static_ip", None) and rule["address"].startswith("from-"):
-                    ruletext = "-s {0} -d {1}".format(rule["address"][len("from-"):], ip)
-                    if rule["netmask"] != 32:
-                        ruletext += "/{0}".format(rule["netmask"])
+                is_inbound = rule["address"].startswith("from-") and getattr(vm, "static_ip", None)
+                if is_inbound:
+                    src_addr = rule["address"][len("from-"):]
+                    src_mask = rule["netmask"]
+                    dst_addr = ip
+                    dst_mask = 32
+                else:
+                    src_addr = ip
+                    src_mask = 32
+                    dst_addr = rule["address"]
+                    dst_mask = rule["netmask"]
 
-                    if rule["proto"] is not None and rule["proto"] != "any":
-                        ruletext += " -p {0}".format(rule["proto"])
-                        if rule["portBegin"] is not None and rule["portBegin"] > 0:
-                            ruletext += " --dport {0}".format(rule["portBegin"])
-                            if rule["portEnd"] is not None and rule["portEnd"] > rule["portBegin"]:
-                                ruletext += ":{0}".format(rule["portEnd"])
+                args = []
 
-                    ruletext += " -j {0}\n".format(rules_action)
-                    iptables += "-A PR-QBS-FORWARD " + ruletext
-                    vm_iptables += "-A FORTRESS-INPUT " + ruletext
-                    continue
+                def constrain(sd, addr, mask):
+                    if mask != 0:
+                        if mask == 32:
+                            args.append("{0} {1}".format(sd, addr))
+                        else:
+                            args.append("{0} {1}/{2}".format(sd, addr, mask))
 
-                iptables += "-A PR-QBS-FORWARD -s {0} -d {1}".format(ip, rule["address"])
-                if rule["netmask"] != 32:
-                    iptables += "/{0}".format(rule["netmask"])
+                constrain("-s", src_addr, src_mask)
+                constrain("-d", dst_addr, dst_mask)
 
                 if rule["proto"] is not None and rule["proto"] != "any":
-                    iptables += " -p {0}".format(rule["proto"])
+                    args.append("-p {0}".format(rule["proto"]))
                     if rule["portBegin"] is not None and rule["portBegin"] > 0:
-                        iptables += " --dport {0}".format(rule["portBegin"])
                         if rule["portEnd"] is not None and rule["portEnd"] > rule["portBegin"]:
-                            iptables += ":{0}".format(rule["portEnd"])
+                            portrange = "{0}:{1}".format(rule["portBegin"], rule["portEnd"])
+                        else:
+                            portrange = rule["portBegin"]
+                        args.append("--dport {0}".format(portrange))
 
-                iptables += " -j {0}\n".format(rules_action)
+                args.append("-j {0}".format(rules_action))
+                ruletext = ' '.join(args)
+
+                iptables += "-A PR-QBS-FORWARD {0}\n".format(ruletext)
+                if is_inbound:
+                    vm_iptables += "-A FORTRESS-INPUT {0}\n".format(ruletext)
 
             if conf["allowDns"] and self.netvm is not None:
                 # PREROUTING does DNAT to NetVM DNSes, so we need self.netvm.

src/usr/lib64/python2.7/site-packages/qubes/modules/qubes-appvm-firewall

@@ -1,5 +1,27 @@
 #!/usr/bin/env python
 
+'''
+This code is intended to replace the very fragile firewall generation code
+that currently runs on dom0, by a lightweight daemon that applies the rules
+on the AppVM (with static IP), responding to rule changes made by the
+administrator on-the-fly.
+
+This daemon is injected into the VM as soon as qrexec capability becomes
+available on the recently-started VM.  The daemon:
+
+1. Reads the QubesDB key /qubes-fortress-iptables-rules.
+2. Atomically applies the rules therein saved therein.
+
+The rules in /qubes-fortress-iptables-rules are generated by the dom0 code
+in 007FortressQubesProxyVM, which in turn are based on the firewall rules
+that the administrator has configured.  These rules are generated and applied
+at the same time as the rules generated and applied on the ProxyVM attached to
+the AppVM, ensuring that the rules in the VM are kept in sync with the rules
+in the ProxyVM at all times.
+
+FIXME: The previous paragraph is still a work in progress.
+'''
+
 import collections
 import logging
 import os