From 9f83e2b6bf9881813a09ab94fa6b89f4c83e628e Mon Sep 17 00:00:00 2001 From: Seth Michael Larson Date: Mon, 29 Jul 2024 16:44:35 -0500 Subject: [PATCH] gh-122133: Authenticate socket connection for `socket.socketpair()` fallback (GH-122134) * Authenticate socket connection for `socket.socketpair()` fallback when the platform does not have a native `socketpair` C API. We authenticate in-process using `getsocketname` and `getpeername` (thanks to Nathaniel J Smith for that suggestion). (cherry picked from commit 78df1043dbdce5c989600616f9f87b4ee72944e5) Co-authored-by: Seth Michael Larson Co-authored-by: Gregory P. Smith --- Lib/socket.py | 17 +++ Lib/test/test_socket.py | 128 +++++++++++++++++- ...-07-22-13-11-28.gh-issue-122133.0mPeta.rst | 5 + 3 files changed, 147 insertions(+), 3 deletions(-) create mode 100644 Misc/NEWS.d/next/Security/2024-07-22-13-11-28.gh-issue-122133.0mPeta.rst diff --git a/Lib/socket.py b/Lib/socket.py index 46fc49ca3233e0..643f218d2f7b69 100755 --- a/Lib/socket.py +++ b/Lib/socket.py @@ -646,6 +646,23 @@ def socketpair(family=AF_INET, type=SOCK_STREAM, proto=0): raise finally: lsock.close() + + # Authenticating avoids using a connection from something else + # able to connect to {host}:{port} instead of us. + # We expect only AF_INET and AF_INET6 families. + try: + if ( + ssock.getsockname() != csock.getpeername() + or csock.getsockname() != ssock.getpeername() + ): + raise ConnectionError("Unexpected peer connection") + except: + # getsockname() and getpeername() can fail + # if either socket isn't connected. + ssock.close() + csock.close() + raise + return (ssock, csock) __all__.append("socketpair") diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py index 043e5543889833..ea812408042eaa 100755 --- a/Lib/test/test_socket.py +++ b/Lib/test/test_socket.py @@ -555,19 +555,27 @@ class SocketPairTest(unittest.TestCase, ThreadableTest): def __init__(self, methodName='runTest'): unittest.TestCase.__init__(self, methodName=methodName) ThreadableTest.__init__(self) + self.cli = None + self.serv = None + + def socketpair(self): + # To be overridden by some child classes. + return socket.socketpair() def setUp(self): - self.serv, self.cli = socket.socketpair() + self.serv, self.cli = self.socketpair() def tearDown(self): - self.serv.close() + if self.serv: + self.serv.close() self.serv = None def clientSetUp(self): pass def clientTearDown(self): - self.cli.close() + if self.cli: + self.cli.close() self.cli = None ThreadableTest.clientTearDown(self) @@ -4613,6 +4621,120 @@ def _testSend(self): self.assertEqual(msg, MSG) +class PurePythonSocketPairTest(SocketPairTest): + + # Explicitly use socketpair AF_INET or AF_INET6 to ensure that is the + # code path we're using regardless platform is the pure python one where + # `_socket.socketpair` does not exist. (AF_INET does not work with + # _socket.socketpair on many platforms). + def socketpair(self): + # called by super().setUp(). + try: + return socket.socketpair(socket.AF_INET6) + except OSError: + return socket.socketpair(socket.AF_INET) + + # Local imports in this class make for easy security fix backporting. + + def setUp(self): + import _socket + self._orig_sp = getattr(_socket, 'socketpair', None) + if self._orig_sp is not None: + # This forces the version using the non-OS provided socketpair + # emulation via an AF_INET socket in Lib/socket.py. + del _socket.socketpair + import importlib + global socket + socket = importlib.reload(socket) + else: + pass # This platform already uses the non-OS provided version. + super().setUp() + + def tearDown(self): + super().tearDown() + import _socket + if self._orig_sp is not None: + # Restore the default socket.socketpair definition. + _socket.socketpair = self._orig_sp + import importlib + global socket + socket = importlib.reload(socket) + + def test_recv(self): + msg = self.serv.recv(1024) + self.assertEqual(msg, MSG) + + def _test_recv(self): + self.cli.send(MSG) + + def test_send(self): + self.serv.send(MSG) + + def _test_send(self): + msg = self.cli.recv(1024) + self.assertEqual(msg, MSG) + + def test_ipv4(self): + cli, srv = socket.socketpair(socket.AF_INET) + cli.close() + srv.close() + + def _test_ipv4(self): + pass + + @unittest.skipIf(not hasattr(_socket, 'IPPROTO_IPV6') or + not hasattr(_socket, 'IPV6_V6ONLY'), + "IPV6_V6ONLY option not supported") + @unittest.skipUnless(socket_helper.IPV6_ENABLED, 'IPv6 required for this test') + def test_ipv6(self): + cli, srv = socket.socketpair(socket.AF_INET6) + cli.close() + srv.close() + + def _test_ipv6(self): + pass + + def test_injected_authentication_failure(self): + orig_getsockname = socket.socket.getsockname + inject_sock = None + + def inject_getsocketname(self): + nonlocal inject_sock + sockname = orig_getsockname(self) + # Connect to the listening socket ahead of the + # client socket. + if inject_sock is None: + inject_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + inject_sock.setblocking(False) + try: + inject_sock.connect(sockname[:2]) + except (BlockingIOError, InterruptedError): + pass + inject_sock.setblocking(True) + return sockname + + sock1 = sock2 = None + try: + socket.socket.getsockname = inject_getsocketname + with self.assertRaises(OSError): + sock1, sock2 = socket.socketpair() + finally: + socket.socket.getsockname = orig_getsockname + if inject_sock: + inject_sock.close() + if sock1: # This cleanup isn't needed on a successful test. + sock1.close() + if sock2: + sock2.close() + + def _test_injected_authentication_failure(self): + # No-op. Exists for base class threading infrastructure to call. + # We could refactor this test into its own lesser class along with the + # setUp and tearDown code to construct an ideal; it is simpler to keep + # it here and live with extra overhead one this _one_ failure test. + pass + + class NonBlockingTCPTests(ThreadedTCPSocketTest): def __init__(self, methodName='runTest'): diff --git a/Misc/NEWS.d/next/Security/2024-07-22-13-11-28.gh-issue-122133.0mPeta.rst b/Misc/NEWS.d/next/Security/2024-07-22-13-11-28.gh-issue-122133.0mPeta.rst new file mode 100644 index 00000000000000..3544eb3824d0da --- /dev/null +++ b/Misc/NEWS.d/next/Security/2024-07-22-13-11-28.gh-issue-122133.0mPeta.rst @@ -0,0 +1,5 @@ +Authenticate the socket connection for the ``socket.socketpair()`` fallback +on platforms where ``AF_UNIX`` is not available like Windows. + +Patch by Gregory P. Smith and Seth Larson . Reported by Ellie +