From 477b1b25768945621d466a8b3f0739297a842439 Mon Sep 17 00:00:00 2001 From: Christian Heimes Date: Tue, 2 Jul 2019 20:39:42 +0200 Subject: [PATCH] bpo-37463: match_hostname requires quad-dotted IPv4 (GH-14499) ssl.match_hostname() no longer accepts IPv4 addresses with additional text after the address and only quad-dotted notation without trailing whitespaces. Some inet_aton() implementations ignore whitespace and all data after whitespace, e.g. '127.0.0.1 whatever'. Short notations like '127.1' for '127.0.0.1' were already filtered out. The bug was initially found by Dominik Czarnota and reported by Paul Kehrer. Signed-off-by: Christian Heimes https://bugs.python.org/issue37463 --- Lib/ssl.py | 29 +++++++++++++------ Lib/test/test_ssl.py | 9 +++++- .../2019-07-01-08-46-14.bpo-37463.1CHwjE.rst | 4 +++ 3 files changed, 32 insertions(+), 10 deletions(-) create mode 100644 Misc/NEWS.d/next/Security/2019-07-01-08-46-14.bpo-37463.1CHwjE.rst diff --git a/Lib/ssl.py b/Lib/ssl.py index 61bd775f75..0726caee49 100644 --- a/Lib/ssl.py +++ b/Lib/ssl.py @@ -327,12 +327,22 @@ def _inet_paton(ipname): Supports IPv4 addresses on all platforms and IPv6 on platforms with IPv6 support. """ - # inet_aton() also accepts strings like '1' - if ipname.count('.') == 3: - try: - return _socket.inet_aton(ipname) - except OSError: - pass + # inet_aton() also accepts strings like '1', '127.1', some also trailing + # data like '127.0.0.1 whatever'. + try: + addr = _socket.inet_aton(ipname) + except OSError: + # not an IPv4 address + pass + else: + if _socket.inet_ntoa(addr) == ipname: + # only accept injective ipnames + return addr + else: + # refuse for short IPv4 notation and additional trailing data + raise ValueError( + "{!r} is not a quad-dotted IPv4 address.".format(ipname) + ) try: return _socket.inet_pton(_socket.AF_INET6, ipname) @@ -346,14 +356,15 @@ def _inet_paton(ipname): raise ValueError("{!r} is not an IPv4 address.".format(ipname)) -def _ipaddress_match(ipname, host_ip): +def _ipaddress_match(cert_ipaddress, host_ip): """Exact matching of IP addresses. RFC 6125 explicitly doesn't define an algorithm for this (section 1.7.2 - "Out of Scope"). """ - # OpenSSL may add a trailing newline to a subjectAltName's IP address - ip = _inet_paton(ipname.rstrip()) + # OpenSSL may add a trailing newline to a subjectAltName's IP address, + # commonly woth IPv6 addresses. Strip off trailing \n. + ip = _inet_paton(cert_ipaddress.rstrip()) return ip == host_ip diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py index ef1723903a..d2b9e2046d 100644 --- a/Lib/test/test_ssl.py +++ b/Lib/test/test_ssl.py @@ -669,9 +669,14 @@ class BasicSocketTests(unittest.TestCase): cert = {'subject': ((('commonName', 'example.com'),),), 'subjectAltName': (('DNS', 'example.com'), ('IP Address', '10.11.12.13'), - ('IP Address', '14.15.16.17'))} + ('IP Address', '14.15.16.17'), + ('IP Address', '127.0.0.1'))} ok(cert, '10.11.12.13') ok(cert, '14.15.16.17') + # socket.inet_ntoa(socket.inet_aton('127.1')) == '127.0.0.1' + fail(cert, '127.1') + fail(cert, '14.15.16.17 ') + fail(cert, '14.15.16.17 extra data') fail(cert, '14.15.16.18') fail(cert, 'example.net') @@ -684,6 +689,8 @@ class BasicSocketTests(unittest.TestCase): ('IP Address', '2003:0:0:0:0:0:0:BABA\n'))} ok(cert, '2001::cafe') ok(cert, '2003::baba') + fail(cert, '2003::baba ') + fail(cert, '2003::baba extra data') fail(cert, '2003::bebe') fail(cert, 'example.net') diff --git a/Misc/NEWS.d/next/Security/2019-07-01-08-46-14.bpo-37463.1CHwjE.rst b/Misc/NEWS.d/next/Security/2019-07-01-08-46-14.bpo-37463.1CHwjE.rst new file mode 100644 index 0000000000..4f4a62e783 --- /dev/null +++ b/Misc/NEWS.d/next/Security/2019-07-01-08-46-14.bpo-37463.1CHwjE.rst @@ -0,0 +1,4 @@ +ssl.match_hostname() no longer accepts IPv4 addresses with additional text +after the address and only quad-dotted notation without trailing +whitespaces. Some inet_aton() implementations ignore whitespace and all data +after whitespace, e.g. '127.0.0.1 whatever'. -- 2.49.0