https://github.com/python/cpython/commit/b98e7790c77a4378ec4b1c71b84138cb930... commit: b98e7790c77a4378ec4b1c71b84138cb930b69b7 branch: 3.7 author: Tapas Kundu <39723251+tapakund@users.noreply.github.com> committer: GitHub <noreply@github.com> date: 2020-06-30T15:20:21-04:00 summary: [3.7] bpo-41004: Resolve hash collisions for IPv4Interface and IPv6Interface (GH-21033) (GH-21231) CVE-2020-14422 The __hash__() methods of classes IPv4Interface and IPv6Interface had issue of generating constant hash values of 32 and 128 respectively causing hash collisions. The fix uses the hash() function to generate hash values for the objects instead of XOR operation (cherry picked from commit b30ee26e366bf509b7538d79bfec6c6d38d53f28) Co-authored-by: Ravi Teja P <rvteja92@gmail.com> Signed-off-by: Tapas Kundu <tkundu@vmware.com> files: A Misc/NEWS.d/next/Security/2020-06-29-16-02-29.bpo-41004.ovF0KZ.rst M Lib/ipaddress.py M Lib/test/test_ipaddress.py diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py index 80249288d73ab..54882934c3dc1 100644 --- a/Lib/ipaddress.py +++ b/Lib/ipaddress.py @@ -1442,7 +1442,7 @@ 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__ @@ -2088,7 +2088,7 @@ 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 index 455b893fb126f..1fb6a929dc2d9 100644 --- a/Lib/test/test_ipaddress.py +++ b/Lib/test/test_ipaddress.py @@ -2091,6 +2091,17 @@ 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 new file mode 100644 index 0000000000000..f5a9db52fff52 --- /dev/null +++ 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).