From c62c9e518b784fe44432a3f4fc265fb95b651906 Mon Sep 17 00:00:00 2001
From: Petr Viktorin <encukou@gmail.com>
Date: Tue, 7 May 2024 11:56:13 +0200
Subject: [PATCH] [3.10] gh-113171: gh-65056: Fix "private" (non-global) IP
 address ranges (GH-113179) (GH-113186) (GH-118177) (GH-118229)

The _private_networks variables, used by various is_private
implementations, were missing some ranges and at the same time had
overly strict ranges (where there are more specific ranges considered
globally reachable by the IANA registries).

This patch updates the ranges with what was missing or otherwise
incorrect.

100.64.0.0/10 is left alone, for now, as it's been made special in [1].

The _address_exclude_many() call returns 8 networks for IPv4, 121
networks for IPv6.

[1] https://github.com/python/cpython/issues/61602

In 3.10 and below, is_private checks whether the network and broadcast
address are both private.
In later versions (where the test wss backported from), it checks
whether they both are in the same private network.

For 0.0.0.0/0, both 0.0.0.0 and 255.225.255.255 are private,
but one is in 0.0.0.0/8 ("This network") and the other in
255.255.255.255/32 ("Limited broadcast").

---------

Co-authored-by: Jakub Stasiak <jakub@stasiak.at>
---
 Doc/library/ipaddress.rst                     | 43 ++++++++-
 Doc/whatsnew/3.10.rst                         |  9 ++
 Lib/ipaddress.py                              | 93 +++++++++++++++----
 Lib/test/test_ipaddress.py                    | 52 +++++++++++
 ...-03-14-01-38-44.gh-issue-113171.VFnObz.rst |  9 ++
 5 files changed, 184 insertions(+), 22 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2024-03-14-01-38-44.gh-issue-113171.VFnObz.rst

#diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
#index 43da72aece9dfd..d6ccf96a4cfec2 100644
#--- a/Doc/whatsnew/3.10.rst
#+++ b/Doc/whatsnew/3.10.rst
#@@ -2348,3 +2348,12 @@ tarfile
#   :exc:`DeprecationWarning`.
#   In Python 3.14, the default will switch to ``'data'``.
#   (Contributed by Petr Viktorin in :pep:`706`.)
#+
#+Notable changes in 3.10.15
#+==========================
#+
#+ipaddress
#+---------
#+
#+* Fixed ``is_global`` and ``is_private`` behavior in ``IPv4Address``,
#+  ``IPv6Address``, ``IPv4Network`` and ``IPv6Network``.
#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
#new file mode 100644
#index 00000000000000..f9a72473be4e2c
#--- /dev/null
#+++ 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.
diff --git a/Doc/library/ipaddress.rst b/Doc/library/ipaddress.rst
index 9c2dff55703273..6f4520e32da841 100644
--- a/Doc/library/ipaddress.rst
+++ b/Doc/library/ipaddress.rst
@@ -188,18 +188,53 @@ 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:: 3.10.15
+
+         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:: 3.10.15
+
+         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/Lib/ipaddress.py b/Lib/ipaddress.py
index 756f1bc38c97fd..94b1761b5f7bf8 100644
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -1323,18 +1323,41 @@ 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
@@ -1538,13 +1561,15 @@ 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'),
@@ -1555,6 +1580,11 @@ 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')
@@ -1996,27 +2026,42 @@ 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
 
@@ -2257,19 +2302,31 @@ 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
index f1ef87f7d589b1..86f3bb504a23ba 100644
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -2263,6 +2263,10 @@ 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)
@@ -2278,6 +2282,40 @@ def testReservedIpv4(self):
         self.assertEqual(False, ipaddress.ip_address('128.0.0.0').is_loopback)
         self.assertEqual(True, ipaddress.ip_network('0.0.0.0').is_unspecified)
 
+    def testPrivateNetworks(self):
+        self.assertEqual(True, ipaddress.ip_network("0.0.0.0/0").is_private)
+        self.assertEqual(False, ipaddress.ip_network("1.0.0.0/8").is_private)
+
+        self.assertEqual(True, ipaddress.ip_network("0.0.0.0/8").is_private)
+        self.assertEqual(True, ipaddress.ip_network("10.0.0.0/8").is_private)
+        self.assertEqual(True, ipaddress.ip_network("127.0.0.0/8").is_private)
+        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)
+        self.assertEqual(True, ipaddress.ip_network("198.18.0.0/15").is_private)
+        self.assertEqual(True, ipaddress.ip_network("198.51.100.0/24").is_private)
+        self.assertEqual(True, ipaddress.ip_network("203.0.113.0/24").is_private)
+        self.assertEqual(True, ipaddress.ip_network("240.0.0.0/4").is_private)
+        self.assertEqual(True, ipaddress.ip_network("255.255.255.255/32").is_private)
+
+        self.assertEqual(False, ipaddress.ip_network("::/0").is_private)
+        self.assertEqual(False, ipaddress.ip_network("::ff/128").is_private)
+
+        self.assertEqual(True, ipaddress.ip_network("::1/128").is_private)
+        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("2001:2::/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)
+        self.assertEqual(True, ipaddress.ip_network("fe80::/10").is_private)
+
     def testReservedIpv6(self):
 
         self.assertEqual(True, ipaddress.ip_network('ffff::').is_multicast)
@@ -2351,6 +2389,20 @@ 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)
