Lookup hostname before connection under reject policy

tests/test_app.py

@@ -428,6 +428,9 @@ class OtherTestBase(AsyncHTTPTestCase):
     sshserver_port = 3300
     headers = {'Cookie': '_xsrf=yummy'}
     debug = False
+    policy = None
+    hostFile = None
+    sysHostFile = None
     body = {
         'hostname': '127.0.0.1',
         'port': '',
@@ -440,9 +443,9 @@ class OtherTestBase(AsyncHTTPTestCase):
         self.body.update(port=str(self.sshserver_port))
         loop = self.io_loop
         options.debug = self.debug
-        options.policy = random.choice(['warning', 'autoadd'])
-        options.hostFile = ''
-        options.sysHostFile = ''
+        options.policy = self.policy if self.policy else random.choice(['warning', 'autoadd'])  # noqa
+        options.hostFile = self.hostFile if self.hostFile else ''
+        options.sysHostFile = self.sysHostFile if self.sysHostFile else ''
         app = make_app(make_handlers(loop, options), get_app_settings(options))
         return app
 
@@ -516,3 +519,21 @@ class TestAppMiscell(OtherTestBase):
         recv = b''.join(lst).decode(data['encoding'])
         self.assertEqual(send, recv)
         ws.close()
+
+
+class TestAppWithRejectPolicy(OtherTestBase):
+
+    policy = 'reject'
+    hostFile = make_tests_data_path('known_hosts_example')
+
+    @tornado.testing.gen_test
+    def test_app_with_hostname_not_in_hostkeys(self):
+        url = self.get_url('/')
+        client = self.get_http_client()
+        body = urlencode(dict(self.body, username='foo'))
+        response = yield client.fetch(url, method='POST', body=body,
+                                      headers=self.headers)
+        data = json.loads(to_str(response.body))
+        self.assertIsNone(data['id'])
+        self.assertIsNone(data['encoding'])
+        self.assertEqual('Connection to 127.0.0.1 is not allowed.', data['status'])  # noqa

webssh/handler.py

@@ -70,6 +70,7 @@ class IndexHandler(MixinHandler, tornado.web.RequestHandler):
         self.loop = loop
         self.policy = policy
         self.host_keys_settings = host_keys_settings
+        self.ssh_client = self.get_ssh_client()
         self.filename = None
         self.result = dict(id=None, status=None, encoding=None)
 
@@ -87,6 +88,14 @@ class IndexHandler(MixinHandler, tornado.web.RequestHandler):
             self.set_status(200)
             self.finish(self.result)
 
+    def get_ssh_client(self):
+        ssh = paramiko.SSHClient()
+        ssh._system_host_keys = self.host_keys_settings['system_host_keys']
+        ssh._host_keys = self.host_keys_settings['host_keys']
+        ssh._host_keys_filename = self.host_keys_settings['host_keys_filename']
+        ssh.set_missing_host_key_policy(self.policy)
+        return ssh
+
     def get_privatekey(self):
         name = 'privatekey'
         lst = self.request.files.get(name)  # multipart form
@@ -143,6 +152,14 @@ class IndexHandler(MixinHandler, tornado.web.RequestHandler):
             raise InvalidValueError('Invalid hostname: {}'.format(value))
         return value
 
+    def lookup_hostname(self, hostname):
+        if isinstance(self.policy, paramiko.RejectPolicy):
+            if self.ssh_client._system_host_keys.lookup(hostname) is None:
+                if self.ssh_client._host_keys.lookup(hostname) is None:
+                    raise ValueError(
+                        'Connection to {} is not allowed.'.format(hostname)
+                    )
+
     def get_port(self):
         value = self.get_value('port')
         try:
@@ -157,6 +174,7 @@ class IndexHandler(MixinHandler, tornado.web.RequestHandler):
 
     def get_args(self):
         hostname = self.get_hostname()
+        self.lookup_hostname(hostname)
         port = self.get_port()
         username = self.get_value('username')
         password = self.get_argument('password', u'')
@@ -182,11 +200,7 @@ class IndexHandler(MixinHandler, tornado.web.RequestHandler):
         return result if result else 'utf-8'
 
     def ssh_connect(self):
-        ssh = paramiko.SSHClient()
-        ssh._system_host_keys = self.host_keys_settings['system_host_keys']
-        ssh._host_keys = self.host_keys_settings['host_keys']
-        ssh._host_keys_filename = self.host_keys_settings['host_keys_filename']
-        ssh.set_missing_host_key_policy(self.policy)
+        ssh = self.ssh_client
 
         try:
             args = self.get_args()