Add support for OpenBSD

sshuttle/methods/pf.py

@@ -198,6 +198,70 @@ def add_rules(self, includes, port, dnsport, nslist):
         super(FreeBsd, self).add_rules(rules)
 
 
+class OpenBsd(Generic):
+    POOL_TICKET_OFFSET = 4
+    RULE_ACTION_OFFSET = 3324
+    ANCHOR_CALL_OFFSET = 1036
+
+    def __init__(self):
+        class pfioc_natlook(Structure):
+            pf_addr = Generic.pf_addr
+            _fields_ = [("saddr", pf_addr),
+                        ("daddr", pf_addr),
+                        ("rsaddr", pf_addr),
+                        ("rdaddr", pf_addr),
+                        ("rdomain", c_uint16),
+                        ("rrdomain", c_uint16),
+                        ("sxport", c_uint16),
+                        ("dxport", c_uint16),
+                        ("rsxport", c_uint16),
+                        ("rdxport", c_uint16),
+                        ("af", c_uint8),                      # sa_family_t
+                        ("proto", c_uint8),
+                        ("proto_variant", c_uint8),
+                        ("direction", c_uint8)]
+
+        self.pfioc_rule = c_char * 3400
+        self.pfioc_natlook = pfioc_natlook
+        super(OpenBsd, self).__init__()
+
+    def add_anchors(self):
+        # before adding anchors and rules we must override the skip lo
+        # that comes by default in openbsd pf.conf so the rules we will add,
+        # which rely on translating/filtering  packets on lo, can work
+        pfctl('-f /dev/stdin', b'match on lo\n')
+        super(OpenBsd, self).add_anchors()
+
+    def add_rules(self, includes, port, dnsport, nslist):
+        tables = [
+            b'table <forward_subnets> {%s}' % b','.join(includes)
+        ]
+        translating_rules = [
+            b'pass in on lo0 inet proto tcp '
+            b'divert-to 127.0.0.1 port %r' % port
+        ]
+        filtering_rules = [
+            b'pass out inet proto tcp '
+            b'to <forward_subnets> route-to lo0 keep state'
+        ]
+
+        if len(nslist) > 0:
+            tables.append(
+                b'table <dns_servers> {%s}' %
+                b','.join([ns[1].encode("ASCII") for ns in nslist]))
+            translating_rules.append(
+                b'pass in on lo0 inet proto udp to <dns_servers>'
+                b'port 53 rdr-to 127.0.0.1 port %r' % dnsport)
+            filtering_rules.append(
+                b'pass out inet proto udp to '
+                b'<dns_servers> port 53 route-to lo0 keep state')
+
+        rules = b'\n'.join(tables + translating_rules + filtering_rules) \
+                + b'\n'
+
+        super(OpenBsd, self).add_rules(rules)
+
+
 class Darwin(FreeBsd):
     RULE_ACTION_OFFSET = 3068
 
@@ -252,6 +316,8 @@ def _get_natlook_port(self, xport):
 
 if sys.platform == 'darwin':
     pf = Darwin()
+elif sys.platform.startswith('openbsd'):
+    pf = OpenBsd()
 else:
     pf = FreeBsd()
 

sshuttle/tests/test_methods_pf.py

@@ -4,7 +4,7 @@
 
 from sshuttle.methods import get_method
 from sshuttle.helpers import Fatal
-from sshuttle.methods.pf import FreeBsd, Darwin
+from sshuttle.methods.pf import FreeBsd, Darwin, OpenBsd
 
 
 def test_get_supported_features():
@@ -131,6 +131,29 @@ def test_firewall_command_freebsd(mock_pf_get_dev, mock_ioctl, mock_stdout):
     ]
 
 
+@patch('sshuttle.methods.pf.pf', OpenBsd())
+@patch('sshuttle.methods.pf.sys.stdout')
+@patch('sshuttle.methods.pf.ioctl')
+@patch('sshuttle.methods.pf.pf_get_dev')
+def test_firewall_command_openbsd(mock_pf_get_dev, mock_ioctl, mock_stdout):
+    method = get_method('pf')
+    assert not method.firewall_command("somthing")
+
+    command = "QUERY_PF_NAT %d,%d,%s,%d,%s,%d\n" % (
+        socket.AF_INET, socket.IPPROTO_TCP,
+        "127.0.0.1", 1025, "127.0.0.2", 1024)
+    assert method.firewall_command(command)
+
+    assert mock_pf_get_dev.mock_calls == [call()]
+    assert mock_ioctl.mock_calls == [
+        call(mock_pf_get_dev(), 0xc0504417, ANY),
+    ]
+    assert mock_stdout.mock_calls == [
+        call.write('QUERY_PF_NAT_SUCCESS 0.0.0.0,0\n'),
+        call.flush(),
+    ]
+
+
 def pfctl(args, stdin=None):
     if args == '-s all':
         return (b'INFO:\nStatus: Disabled\nanother mary had a little lamb\n',
@@ -301,3 +324,80 @@ def test_setup_firewall_freebsd(mock_pf_get_dev, mock_ioctl, mock_pfctl):
     mock_pf_get_dev.reset_mock()
     mock_pfctl.reset_mock()
     mock_ioctl.reset_mock()
+
+
+@patch('sshuttle.helpers.verbose', new=3)
+@patch('sshuttle.methods.pf.pf', OpenBsd())
+@patch('sshuttle.methods.pf.pfctl')
+@patch('sshuttle.methods.pf.ioctl')
+@patch('sshuttle.methods.pf.pf_get_dev')
+def test_setup_firewall_openbsd(mock_pf_get_dev, mock_ioctl, mock_pfctl):
+    mock_pfctl.side_effect = pfctl
+
+    method = get_method('pf')
+    assert method.name == 'pf'
+
+    with pytest.raises(Exception) as excinfo:
+        method.setup_firewall(
+            1024, 1026,
+            [(10, u'2404:6800:4004:80c::33')],
+            10,
+            [(10, 64, False, u'2404:6800:4004:80c::'),
+                (10, 128, True, u'2404:6800:4004:80c::101f')],
+            True)
+    assert str(excinfo.value) \
+        == 'Address family "AF_INET6" unsupported by pf method_name'
+    assert mock_pf_get_dev.mock_calls == []
+    assert mock_ioctl.mock_calls == []
+    assert mock_pfctl.mock_calls == []
+
+    with pytest.raises(Exception) as excinfo:
+        method.setup_firewall(
+            1025, 1027,
+            [(2, u'1.2.3.33')],
+            2,
+            [(2, 24, False, u'1.2.3.0'), (2, 32, True, u'1.2.3.66')],
+            True)
+    assert str(excinfo.value) == 'UDP not supported by pf method_name'
+    assert mock_pf_get_dev.mock_calls == []
+    assert mock_ioctl.mock_calls == []
+    assert mock_pfctl.mock_calls == []
+
+    method.setup_firewall(
+        1025, 1027,
+        [(2, u'1.2.3.33')],
+        2,
+        [(2, 24, False, u'1.2.3.0'), (2, 32, True, u'1.2.3.66')],
+        False)
+    assert mock_ioctl.mock_calls == [
+        call(mock_pf_get_dev(), 0xcd48441a, ANY),
+        call(mock_pf_get_dev(), 0xcd48441a, ANY),
+    ]
+    assert mock_pfctl.mock_calls == [
+        call('-f /dev/stdin', b'match on lo\n'),
+        call('-s all'),
+        call('-a sshuttle -f /dev/stdin',
+             b'table <forward_subnets> {!1.2.3.66/32,1.2.3.0/24}\n'
+             b'table <dns_servers> {1.2.3.33}\n'
+             b'pass in on lo0 inet proto tcp divert-to 127.0.0.1 port 1025\n'
+             b'pass in on lo0 inet proto udp to '
+             b'<dns_servers>port 53 rdr-to 127.0.0.1 port 1027\n'
+             b'pass out inet proto tcp to '
+             b'<forward_subnets> route-to lo0 keep state\n'
+             b'pass out inet proto udp to '
+             b'<dns_servers> port 53 route-to lo0 keep state\n'),
+        call('-e'),
+    ]
+    mock_pf_get_dev.reset_mock()
+    mock_ioctl.reset_mock()
+    mock_pfctl.reset_mock()
+
+    method.restore_firewall(1025, 2, False)
+    assert mock_ioctl.mock_calls == []
+    assert mock_pfctl.mock_calls == [
+        call('-a sshuttle -F all'),
+        call("-d"),
+    ]
+    mock_pf_get_dev.reset_mock()
+    mock_pfctl.reset_mock()
+    mock_ioctl.reset_mock()