[3.11] gh-113171: gh-65056: Fix "private" (non-global) IP address ranges (GH-113179) (GH-113186) (GH-118177) (#118227)

encukou · web-flow · commit ba431579efdc · 2024-04-25T13:45:48.000+01:00
diff --git a/Doc/library/ipaddress.rst b/Doc/library/ipaddress.rst
@@ -178,18 +178,53 @@ write code that handles both IP versions correctly.  Address objects are
 
    .. attribute:: is_private
 
-      ``True`` if the address is allocated for private networks.  See
+      ``True`` if the address is defined as not globally reachable by
       iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
-      (for IPv6).
+      (for IPv6) with the following exceptions:
+
+      * ``is_private`` is ``False`` for the shared address space (``100.64.0.0/10``)
+      * For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+        semantics of the underlying IPv4 addresses and the following condition holds
+        (see :attr:`IPv6Address.ipv4_mapped`)::
+
+            address.is_private == address.ipv4_mapped.is_private
+
+      ``is_private`` has value opposite to :attr:`is_global`, except for the shared address space
+      (``100.64.0.0/10`` range) where they are both ``False``.
+
+      .. versionchanged:: 3.11.10
+
+         Fixed some false positives and false negatives.
+
+         * ``192.0.0.0/24`` is considered private with the exception of ``192.0.0.9/32`` and
+           ``192.0.0.10/32`` (previously: only the ``192.0.0.0/29`` sub-range was considered private).
+         * ``64:ff9b:1::/48`` is considered private.
+         * ``2002::/16`` is considered private.
+         * There are exceptions within ``2001::/23`` (otherwise considered private): ``2001:1::1/128``,
+           ``2001:1::2/128``, ``2001:3::/32``, ``2001:4:112::/48``, ``2001:20::/28``, ``2001:30::/28``.
+           The exceptions are not considered private.
 
    .. attribute:: is_global
 
-      ``True`` if the address is allocated for public networks.  See
+      ``True`` if the address is defined as globally reachable by
       iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
-      (for IPv6).
+      (for IPv6) with the following exception:
+
+      For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+      semantics of the underlying IPv4 addresses and the following condition holds
+      (see :attr:`IPv6Address.ipv4_mapped`)::
+
+         address.is_global == address.ipv4_mapped.is_global
+
+      ``is_global`` has value opposite to :attr:`is_private`, except for the shared address space
+      (``100.64.0.0/10`` range) where they are both ``False``.
 
       .. versionadded:: 3.4
 
+      .. versionchanged:: 3.11.10
+
+         Fixed some false positives and false negatives, see :attr:`is_private` for details.
+
    .. attribute:: is_unspecified
 
       ``True`` if the address is unspecified.  See :RFC:`5735` (for IPv4)
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
@@ -2727,3 +2727,12 @@ OpenSSL
 * Windows builds and macOS installers from python.org now use OpenSSL 3.0.
 
 .. _libb2: https://www.blake2.net/
+
+Notable changes in 3.11.10
+==========================
+
+ipaddress
+---------
+
+* Fixed ``is_global`` and ``is_private`` behavior in ``IPv4Address``,
+  ``IPv6Address``, ``IPv4Network`` and ``IPv6Network``.
diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
@@ -1086,7 +1086,11 @@ def is_private(self):
         """
         return any(self.network_address in priv_network and
                    self.broadcast_address in priv_network
-                   for priv_network in self._constants._private_networks)
+                   for priv_network in self._constants._private_networks) and all(
+                    self.network_address not in network and
+                    self.broadcast_address not in network
+                    for network in self._constants._private_networks_exceptions
+                )
 
     @property
     def is_global(self):
@@ -1333,18 +1337,41 @@ def is_reserved(self):
     @property
     @functools.lru_cache()
     def is_private(self):
-        """Test if this address is allocated for private networks.
+        """``True`` if the address is defined as not globally reachable by
+        iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
+        (for IPv6) with the following exceptions:
 
-        Returns:
-            A boolean, True if the address is reserved per
-            iana-ipv4-special-registry.
+        * ``is_private`` is ``False`` for ``100.64.0.0/10``
+        * For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+            semantics of the underlying IPv4 addresses and the following condition holds
+            (see :attr:`IPv6Address.ipv4_mapped`)::
 
+                address.is_private == address.ipv4_mapped.is_private
+
+        ``is_private`` has value opposite to :attr:`is_global`, except for the ``100.64.0.0/10``
+        IPv4 range where they are both ``False``.
         """
-        return any(self in net for net in self._constants._private_networks)
+        return (
+            any(self in net for net in self._constants._private_networks)
+            and all(self not in net for net in self._constants._private_networks_exceptions)
+        )
 
     @property
     @functools.lru_cache()
     def is_global(self):
+        """``True`` if the address is defined as globally reachable by
+        iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
+        (for IPv6) with the following exception:
+
+        For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+        semantics of the underlying IPv4 addresses and the following condition holds
+        (see :attr:`IPv6Address.ipv4_mapped`)::
+
+            address.is_global == address.ipv4_mapped.is_global
+
+        ``is_global`` has value opposite to :attr:`is_private`, except for the ``100.64.0.0/10``
+        IPv4 range where they are both ``False``.
+        """
         return self not in self._constants._public_network and not self.is_private
 
     @property
@@ -1548,13 +1575,15 @@ class _IPv4Constants:
 
     _public_network = IPv4Network('100.64.0.0/10')
 
+    # Not globally reachable address blocks listed on
+    # https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml
     _private_networks = [
         IPv4Network('0.0.0.0/8'),
         IPv4Network('10.0.0.0/8'),
         IPv4Network('127.0.0.0/8'),
         IPv4Network('169.254.0.0/16'),
         IPv4Network('172.16.0.0/12'),
-        IPv4Network('192.0.0.0/29'),
+        IPv4Network('192.0.0.0/24'),
         IPv4Network('192.0.0.170/31'),
         IPv4Network('192.0.2.0/24'),
         IPv4Network('192.168.0.0/16'),
@@ -1565,6 +1594,11 @@ class _IPv4Constants:
         IPv4Network('255.255.255.255/32'),
         ]
 
+    _private_networks_exceptions = [
+        IPv4Network('192.0.0.9/32'),
+        IPv4Network('192.0.0.10/32'),
+    ]
+
     _reserved_network = IPv4Network('240.0.0.0/4')
 
     _unspecified_address = IPv4Address('0.0.0.0')
@@ -2010,27 +2044,42 @@ def is_site_local(self):
     @property
     @functools.lru_cache()
     def is_private(self):
-        """Test if this address is allocated for private networks.
+        """``True`` if the address is defined as not globally reachable by
+        iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
+        (for IPv6) with the following exceptions:
 
-        Returns:
-            A boolean, True if the address is reserved per
-            iana-ipv6-special-registry, or is ipv4_mapped and is
-            reserved in the iana-ipv4-special-registry.
+        * ``is_private`` is ``False`` for ``100.64.0.0/10``
+        * For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+            semantics of the underlying IPv4 addresses and the following condition holds
+            (see :attr:`IPv6Address.ipv4_mapped`)::
 
+                address.is_private == address.ipv4_mapped.is_private
+
+        ``is_private`` has value opposite to :attr:`is_global`, except for the ``100.64.0.0/10``
+        IPv4 range where they are both ``False``.
         """
         ipv4_mapped = self.ipv4_mapped
         if ipv4_mapped is not None:
             return ipv4_mapped.is_private
-        return any(self in net for net in self._constants._private_networks)
+        return (
+            any(self in net for net in self._constants._private_networks)
+            and all(self not in net for net in self._constants._private_networks_exceptions)
+        )
 
     @property
     def is_global(self):
-        """Test if this address is allocated for public networks.
+        """``True`` if the address is defined as globally reachable by
+        iana-ipv4-special-registry_ (for IPv4) or iana-ipv6-special-registry_
+        (for IPv6) with the following exception:
 
-        Returns:
-            A boolean, true if the address is not reserved per
-            iana-ipv6-special-registry.
+        For IPv4-mapped IPv6-addresses the ``is_private`` value is determined by the
+        semantics of the underlying IPv4 addresses and the following condition holds
+        (see :attr:`IPv6Address.ipv4_mapped`)::
+
+            address.is_global == address.ipv4_mapped.is_global
 
+        ``is_global`` has value opposite to :attr:`is_private`, except for the ``100.64.0.0/10``
+        IPv4 range where they are both ``False``.
         """
         return not self.is_private
 
@@ -2271,19 +2320,31 @@ class _IPv6Constants:
 
     _multicast_network = IPv6Network('ff00::/8')
 
+    # Not globally reachable address blocks listed on
+    # https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml
     _private_networks = [
         IPv6Network('::1/128'),
         IPv6Network('::/128'),
         IPv6Network('::ffff:0:0/96'),
+        IPv6Network('64:ff9b:1::/48'),
         IPv6Network('100::/64'),
         IPv6Network('2001::/23'),
-        IPv6Network('2001:2::/48'),
         IPv6Network('2001:db8::/32'),
-        IPv6Network('2001:10::/28'),
+        # IANA says N/A, let's consider it not globally reachable to be safe
+        IPv6Network('2002::/16'),
         IPv6Network('fc00::/7'),
         IPv6Network('fe80::/10'),
         ]
 
+    _private_networks_exceptions = [
+        IPv6Network('2001:1::1/128'),
+        IPv6Network('2001:1::2/128'),
+        IPv6Network('2001:3::/32'),
+        IPv6Network('2001:4:112::/48'),
+        IPv6Network('2001:20::/28'),
+        IPv6Network('2001:30::/28'),
+    ]
+
     _reserved_networks = [
         IPv6Network('::/8'), IPv6Network('100::/8'),
         IPv6Network('200::/7'), IPv6Network('400::/6'),
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
@@ -2269,6 +2269,10 @@ def testReservedIpv4(self):
         self.assertEqual(True, ipaddress.ip_address(
                 '172.31.255.255').is_private)
         self.assertEqual(False, ipaddress.ip_address('172.32.0.0').is_private)
+        self.assertFalse(ipaddress.ip_address('192.0.0.0').is_global)
+        self.assertTrue(ipaddress.ip_address('192.0.0.9').is_global)
+        self.assertTrue(ipaddress.ip_address('192.0.0.10').is_global)
+        self.assertFalse(ipaddress.ip_address('192.0.0.255').is_global)
 
         self.assertEqual(True,
                          ipaddress.ip_address('169.254.100.200').is_link_local)
@@ -2294,6 +2298,7 @@ def testPrivateNetworks(self):
         self.assertEqual(True, ipaddress.ip_network("169.254.0.0/16").is_private)
         self.assertEqual(True, ipaddress.ip_network("172.16.0.0/12").is_private)
         self.assertEqual(True, ipaddress.ip_network("192.0.0.0/29").is_private)
+        self.assertEqual(False, ipaddress.ip_network("192.0.0.9/32").is_private)
         self.assertEqual(True, ipaddress.ip_network("192.0.0.170/31").is_private)
         self.assertEqual(True, ipaddress.ip_network("192.0.2.0/24").is_private)
         self.assertEqual(True, ipaddress.ip_network("192.168.0.0/16").is_private)
@@ -2310,8 +2315,8 @@ def testPrivateNetworks(self):
         self.assertEqual(True, ipaddress.ip_network("::/128").is_private)
         self.assertEqual(True, ipaddress.ip_network("::ffff:0:0/96").is_private)
         self.assertEqual(True, ipaddress.ip_network("100::/64").is_private)
-        self.assertEqual(True, ipaddress.ip_network("2001::/23").is_private)
         self.assertEqual(True, ipaddress.ip_network("2001:2::/48").is_private)
+        self.assertEqual(False, ipaddress.ip_network("2001:3::/48").is_private)
         self.assertEqual(True, ipaddress.ip_network("2001:db8::/32").is_private)
         self.assertEqual(True, ipaddress.ip_network("2001:10::/28").is_private)
         self.assertEqual(True, ipaddress.ip_network("fc00::/7").is_private)
@@ -2390,6 +2395,20 @@ def testReservedIpv6(self):
         self.assertEqual(True, ipaddress.ip_address('0::0').is_unspecified)
         self.assertEqual(False, ipaddress.ip_address('::1').is_unspecified)
 
+        self.assertFalse(ipaddress.ip_address('64:ff9b:1::').is_global)
+        self.assertFalse(ipaddress.ip_address('2001::').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:1::1').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:1::2').is_global)
+        self.assertFalse(ipaddress.ip_address('2001:2::').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:3::').is_global)
+        self.assertFalse(ipaddress.ip_address('2001:4::').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:4:112::').is_global)
+        self.assertFalse(ipaddress.ip_address('2001:10::').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:20::').is_global)
+        self.assertTrue(ipaddress.ip_address('2001:30::').is_global)
+        self.assertFalse(ipaddress.ip_address('2001:40::').is_global)
+        self.assertFalse(ipaddress.ip_address('2002::').is_global)
+
         # some generic IETF reserved addresses
         self.assertEqual(True, ipaddress.ip_address('100::').is_reserved)
         self.assertEqual(True, ipaddress.ip_network('4000::1/128').is_reserved)
diff --git a/Misc/NEWS.d/next/Library/2024-03-14-01-38-44.gh-issue-113171.VFnObz.rst b/Misc/NEWS.d/next/Library/2024-03-14-01-38-44.gh-issue-113171.VFnObz.rst
@@ -0,0 +1,9 @@
+Fixed various false positives and false negatives in
+
+* :attr:`ipaddress.IPv4Address.is_private` (see these docs for details)
+* :attr:`ipaddress.IPv4Address.is_global`
+* :attr:`ipaddress.IPv6Address.is_private`
+* :attr:`ipaddress.IPv6Address.is_global`
+
+Also in the corresponding :class:`ipaddress.IPv4Network` and :class:`ipaddress.IPv6Network`
+attributes.
