Pull out ssl validation into validator class

util/config/validators/test/test_validate_ssl.py

@@ -0,0 +1,62 @@
+import pytest
+
+from mock import patch
+from tempfile import NamedTemporaryFile
+
+from util.config.validators import ConfigValidationException
+from util.config.validators.validate_ssl import SSLValidator, SSL_FILENAMES
+from test.test_ssl_util import generate_test_cert
+
+@pytest.mark.parametrize('unvalidated_config', [
+  ({}),
+  ({'PREFERRED_URL_SCHEME': 'http'}),
+  ({'PREFERRED_URL_SCHEME': 'https', 'EXTERNAL_TLS_TERMINATION': True}),
+])
+def test_skip_validate_ssl(unvalidated_config):
+  validator = SSLValidator()
+  validator.validate(unvalidated_config, None, None)
+
+
+@pytest.mark.parametrize('cert, expected_error, error_message', [
+  ('invalidcert', ConfigValidationException, 'Could not load SSL certificate: no start line'),
+  (generate_test_cert(hostname='someserver'), None, None),
+  (generate_test_cert(hostname='invalidserver'), ConfigValidationException,
+   'Supported names "invalidserver" in SSL cert do not match server hostname "someserver"'),
+])
+def test_validate_ssl(cert, expected_error, error_message):
+  with NamedTemporaryFile(delete=False) as cert_file:
+    cert_file.write(cert[0])
+    cert_file.seek(0)
+
+    with NamedTemporaryFile(delete=False) as key_file:
+      key_file.write(cert[1])
+      key_file.seek(0)
+
+    def return_true(filename):
+      return True
+
+    def get_volume_file(filename):
+      if filename == SSL_FILENAMES[0]:
+        return open(cert_file.name)
+
+      if filename == SSL_FILENAMES[1]:
+        return open(key_file.name)
+
+      return None
+
+    config = {
+      'PREFERRED_URL_SCHEME': 'https',
+      'SERVER_HOSTNAME': 'someserver',
+    }
+
+    with patch('app.config_provider.volume_file_exists', return_true):
+      with patch('app.config_provider.get_volume_file', get_volume_file):
+        validator = SSLValidator()
+
+        if expected_error is not None:
+          with pytest.raises(expected_error) as ipe:
+            validator.validate(config, None, None)
+
+          assert ipe.value.message == error_message
+        else:
+          validator.validate(config, None, None)

util/config/validators/validate_ssl.py

@@ -0,0 +1,59 @@
+from app import config_provider
+from util.config.validators import BaseValidator, ConfigValidationException
+from util.security.ssl import load_certificate, CertInvalidException, KeyInvalidException
+
+SSL_FILENAMES = ['ssl.cert', 'ssl.key']
+
+class SSLValidator(BaseValidator):
+  name = "ssl"
+
+  @classmethod
+  def validate(cls, config, user, user_password):
+    """ Validates the SSL configuration (if enabled). """
+
+    # Skip if non-SSL.
+    if config.get('PREFERRED_URL_SCHEME', 'http') != 'https':
+      return
+
+    # Skip if externally terminated.
+    if config.get('EXTERNAL_TLS_TERMINATION', False) is True:
+      return
+
+    # Verify that we have all the required SSL files.
+    for filename in SSL_FILENAMES:
+      if not config_provider.volume_file_exists(filename):
+        raise ConfigValidationException('Missing required SSL file: %s' % filename)
+
+    # Read the contents of the SSL certificate.
+    with config_provider.get_volume_file(SSL_FILENAMES[0]) as f:
+      cert_contents = f.read()
+
+    # Validate the certificate.
+    try:
+      certificate = load_certificate(cert_contents)
+    except CertInvalidException as cie:
+      raise ConfigValidationException('Could not load SSL certificate: %s' % cie.message)
+
+    # Verify the certificate has not expired.
+    if certificate.expired:
+      raise ConfigValidationException('The specified SSL certificate has expired.')
+
+    # Verify the hostname matches the name in the certificate.
+    if not certificate.matches_name(config['SERVER_HOSTNAME']):
+      msg = ('Supported names "%s" in SSL cert do not match server hostname "%s"' %
+             (', '.join(list(certificate.names)), config['SERVER_HOSTNAME']))
+      raise ConfigValidationException(msg)
+
+    # Verify the private key against the certificate.
+    private_key_path = None
+    with config_provider.get_volume_file(SSL_FILENAMES[1]) as f:
+      private_key_path = f.name
+
+    if not private_key_path:
+      # Only in testing.
+      return
+
+    try:
+      certificate.validate_private_key(private_key_path)
+    except KeyInvalidException as kie:
+      raise ConfigValidationException('SSL private key failed to validate: %s' % kie.message)