python · larryhastings · Aug 4, 2020 · Jun 30, 2020 · Jul 16, 2020 · Aug 4, 2020
diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
@@ -1418,7 +1418,7 @@ def __lt__(self, other):
            return False

    def __hash__(self):
-        return self._ip ^ self._prefixlen ^ int(self.network.network_address)
+        return hash((self._ip, self._prefixlen, int(self.network.network_address)))

    __reduce__ = _IPAddressBase.__reduce__

@@ -2109,7 +2109,7 @@ def __lt__(self, other):
            return False

    def __hash__(self):
-        return self._ip ^ self._prefixlen ^ int(self.network.network_address)
+        return hash((self._ip, self._prefixlen, int(self.network.network_address)))

    __reduce__ = _IPAddressBase.__reduce__


diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
@@ -1966,6 +1966,17 @@ def testsixtofour(self):
                         sixtofouraddr.sixtofour)
        self.assertFalse(bad_addr.sixtofour)

+    # issue41004 Hash collisions in IPv4Interface and IPv6Interface
+    def testV4HashIsNotConstant(self):
+        ipv4_address1 = ipaddress.IPv4Interface("1.2.3.4")
+        ipv4_address2 = ipaddress.IPv4Interface("2.3.4.5")
+        self.assertNotEqual(ipv4_address1.__hash__(), ipv4_address2.__hash__())
+
+    # issue41004 Hash collisions in IPv4Interface and IPv6Interface
+    def testV6HashIsNotConstant(self):
+        ipv6_address1 = ipaddress.IPv6Interface("2001:658:22a:cafe:200:0:0:1")
+        ipv6_address2 = ipaddress.IPv6Interface("2001:658:22a:cafe:200:0:0:2")
+        self.assertNotEqual(ipv6_address1.__hash__(), ipv6_address2.__hash__())

 if __name__ == '__main__':
    unittest.main()
diff --git a/Misc/NEWS.d/next/Security/2020-06-29-16-02-29.bpo-41004.ovF0KZ.rst b/Misc/NEWS.d/next/Security/2020-06-29-16-02-29.bpo-41004.ovF0KZ.rst
@@ -0,0 +1 @@
+CVE-2020-14422: The __hash__() methods of  ipaddress.IPv4Interface and ipaddress.IPv6Interface incorrectly generated constant hash values of 32 and 128 respectively. This resulted in always causing hash collisions. The fix uses hash() to generate hash values for the tuple of (address, mask length, network address).
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		CVE-2020-14422: The __hash__() methods of ipaddress.IPv4Interface and ipaddress.IPv6Interface incorrectly generated constant hash values of 32 and 128 respectively. This resulted in always causing hash collisions. The fix uses hash() to generate hash values for the tuple of (address, mask length, network address).