PYTHON-2798 Workaround windows cert issue with SSL_CERT_FILE (#670)

(cherry picked from commit 6d1ebf4)

Author: ShaneHarvey

.evergreen/run-tests.sh

@@ -166,13 +166,15 @@ if [ -n "$TEST_ENCRYPTION" ]; then
     . $DRIVERS_TOOLS/.evergreen/csfle/set-temp-creds.sh
 
     # Start the mock KMS servers.
-    if [ "$OS" != "Windows_NT" ]; then
-        pushd ${DRIVERS_TOOLS}/.evergreen/csfle
-        python -u lib/kms_http_server.py --ca_file ../x509gen/ca.pem --cert_file ../x509gen/expired.pem --port 8000 &
-        python -u lib/kms_http_server.py --ca_file ../x509gen/ca.pem --cert_file ../x509gen/wrong-host.pem --port 8001 &
-        trap 'kill $(jobs -p)' EXIT HUP
-        popd
+    if [ "$OS" = "Windows_NT" ]; then
+        # Remove after BUILD-13574.
+        python -m pip install certifi
     fi
+    pushd ${DRIVERS_TOOLS}/.evergreen/csfle
+    python -u lib/kms_http_server.py --ca_file ../x509gen/ca.pem --cert_file ../x509gen/expired.pem --port 8000 &
+    python -u lib/kms_http_server.py --ca_file ../x509gen/ca.pem --cert_file ../x509gen/wrong-host.pem --port 8001 &
+    trap 'kill $(jobs -p)' EXIT HUP
+    popd
 fi
 
 PYTHON_IMPL=$($PYTHON -c "import platform, sys; sys.stdout.write(platform.python_implementation())")

test/__init__.py

@@ -50,7 +50,7 @@
 from pymongo.common import partition_node
 from pymongo.hello_compat import HelloCompat
 from pymongo.server_api import ServerApi
-from pymongo.ssl_support import HAVE_SSL, validate_cert_reqs
+from pymongo.ssl_support import HAVE_SSL, _ssl
 from pymongo.uri_parser import parse_uri
 from test.version import Version
 
@@ -885,6 +885,10 @@ def setUpClass(cls):
         else:
             cls.credentials = {}
 
+    def patch_system_certs(self, ca_certs):
+        patcher = SystemCertsPatcher(ca_certs)
+        self.addCleanup(patcher.disable)
+
 
 # Use assertRaisesRegex if available, otherwise use Python 2.7's
 # deprecated assertRaisesRegexp, with a 'p'.
@@ -1030,3 +1034,23 @@ def clear_warning_registry():
     for name, module in list(sys.modules.items()):
         if hasattr(module, "__warningregistry__"):
             setattr(module, "__warningregistry__", {})
+
+
+class SystemCertsPatcher(object):
+    def __init__(self, ca_certs):
+        if sys.version_info < (2, 7, 9):
+            raise SkipTest("Can't load system CA certificates.")
+        if (ssl.OPENSSL_VERSION.lower().startswith('libressl') and
+                sys.platform == 'darwin' and not _ssl.IS_PYOPENSSL):
+            raise SkipTest(
+                "LibreSSL on OSX doesn't support setting CA certificates "
+                "using SSL_CERT_FILE environment variable.")
+        self.original_certs = os.environ.get('SSL_CERT_FILE')
+        # Tell OpenSSL where CA certificates live.
+        os.environ['SSL_CERT_FILE'] = ca_certs
+
+    def disable(self):
+        if self.original_certs is None:
+            os.environ.pop('SSL_CERT_FILE')
+        else:
+            os.environ['SSL_CERT_FILE'] = self.original_certs

test/test_encryption.py

@@ -19,7 +19,6 @@
 import os
 import traceback
 import socket
-import ssl
 import sys
 import textwrap
 import uuid
@@ -51,10 +50,14 @@
                             WriteError)
 from pymongo.mongo_client import MongoClient
 from pymongo.operations import InsertOne
-from pymongo.ssl_support import _ssl
 from pymongo.write_concern import WriteConcern
+from test.test_ssl import CA_PEM
 
-from test import unittest, IntegrationTest, PyMongoTestCase, client_context
+from test import (unittest,
+                  client_context,
+                  IntegrationTest,
+                  PyMongoTestCase,
+                  SystemCertsPatcher)
 from test.utils import (TestCreator,
                         camel_to_snake_args,
                         OvertCommandListener,
@@ -63,7 +66,26 @@
                         rs_or_single_client,
                         wait_until)
 from test.utils_spec_runner import SpecRunner
-from test.test_ssl import CA_PEM
+
+try:
+    import certifi
+    HAVE_CERTIFI = True
+except ImportError:
+    HAVE_CERTIFI = False
+
+patcher = None
+
+
+def setUpModule():
+    if sys.platform == 'win32' and HAVE_CERTIFI:
+        # Remove after BUILD-13574.
+        global patcher
+        patcher = SystemCertsPatcher(certifi.where())
+
+
+def tearDownModule():
+    if patcher:
+        patcher.disable()
 
 
 def get_client_opts(client):
@@ -1635,25 +1657,11 @@ def test_bypassAutoEncryption(self):
 
 # https://github.com/mongodb/specifications/tree/master/source/client-side-encryption/tests#kms-tls-tests
 class TestKmsTLSProse(EncryptionIntegrationTest):
-    @unittest.skipIf(sys.platform == 'win32',
-                     "Can't test system ca certs on Windows")
-    @unittest.skipIf(ssl.OPENSSL_VERSION.lower().startswith('libressl') and
-                     sys.platform == 'darwin' and not _ssl.IS_PYOPENSSL,
-                     "LibreSSL on OSX doesn't support setting CA certificates "
-                     "using SSL_CERT_FILE environment variable.")
     @unittest.skipUnless(any(AWS_CREDS.values()),
                          'AWS environment credentials are not set')
     def setUp(self):
-        self.original_certs = os.environ.get('SSL_CERT_FILE')
-        def restore_certs():
-            if self.original_certs is None:
-                os.environ.pop('SSL_CERT_FILE')
-            else:
-                os.environ['SSL_CERT_FILE'] = self.original_certs
-        # Tell OpenSSL where CA certificates live.
-        os.environ['SSL_CERT_FILE'] = CA_PEM
-        self.addCleanup(restore_certs)
-
+        super(TestKmsTLSProse, self).setUp()
+        self.patch_system_certs(CA_PEM)
         self.client_encrypted = ClientEncryption(
             {'aws': AWS_CREDS}, 'keyvault.datakeys', self.client, OPTS)
         self.addCleanup(self.client_encrypted.close)

test/test_ssl.py

@@ -460,48 +460,32 @@ def test_validation_with_system_ca_certs(self):
         #   --sslCAFile=/path/to/pymongo/test/certificates/ca.pem
         #   --sslWeakCertificateValidation
         #
-        if sys.platform == "win32":
-            raise SkipTest("Can't test system ca certs on Windows.")
-
-        if sys.version_info < (2, 7, 9):
-            raise SkipTest("Can't load system CA certificates.")
-
-        if (ssl.OPENSSL_VERSION.lower().startswith('libressl') and
-                sys.platform == 'darwin' and not _ssl.IS_PYOPENSSL):
-            raise SkipTest(
-                "LibreSSL on OSX doesn't support setting CA certificates "
-                "using SSL_CERT_FILE environment variable.")
-
-        # Tell OpenSSL where CA certificates live.
-        os.environ['SSL_CERT_FILE'] = CA_PEM
-        try:
-            with self.assertRaises(ConnectionFailure):
-                # Server cert is verified but hostname matching fails
-                connected(MongoClient('server',
-                                      ssl=True,
-                                      serverSelectionTimeoutMS=100,
-                                      **self.credentials))
-
-            # Server cert is verified. Disable hostname matching.
+        self.patch_system_certs(CA_PEM)
+        with self.assertRaises(ConnectionFailure):
+            # Server cert is verified but hostname matching fails
             connected(MongoClient('server',
                                   ssl=True,
-                                  ssl_match_hostname=False,
                                   serverSelectionTimeoutMS=100,
                                   **self.credentials))
 
-            # Server cert and hostname are verified.
-            connected(MongoClient('localhost',
-                                  ssl=True,
-                                  serverSelectionTimeoutMS=100,
-                                  **self.credentials))
+        # Server cert is verified. Disable hostname matching.
+        connected(MongoClient('server',
+                              ssl=True,
+                              ssl_match_hostname=False,
+                              serverSelectionTimeoutMS=100,
+                              **self.credentials))
 
-            # Server cert and hostname are verified.
-            connected(
-                MongoClient(
-                    'mongodb://localhost/?ssl=true&serverSelectionTimeoutMS=100',
-                    **self.credentials))
-        finally:
-            os.environ.pop('SSL_CERT_FILE')
+        # Server cert and hostname are verified.
+        connected(MongoClient('localhost',
+                              ssl=True,
+                              serverSelectionTimeoutMS=100,
+                              **self.credentials))
+
+        # Server cert and hostname are verified.
+        connected(
+            MongoClient(
+                'mongodb://localhost/?ssl=true&serverSelectionTimeoutMS=100',
+                **self.credentials))
 
     def test_system_certs_config_error(self):
         ctx = get_ssl_context(