quay/util/secscan/api.py

import logging
import requests

from flask import url_for
from urlparse import urljoin

from data.database import CloseForLongOperation
from data import model
from data.model.storage import get_storage_locations
from util.secscan.validator import SecurityConfigValidator
from util.security.instancekeys import InstanceKeys
from util.security.registry_jwt import generate_bearer_token, build_context_and_subject
from util import get_app_url


TOKEN_VALIDITY_LIFETIME_S = 60  # Amount of time the security scanner has to call the layer URL


logger = logging.getLogger(__name__)


class AnalyzeLayerException(Exception):
  """ Exception raised when a layer fails to analyze due to a *client-side* issue. """

class APIRequestFailure(Exception):
  """ Exception raised when there is a failure to conduct an API request. """


_API_METHOD_INSERT = 'layers'
_API_METHOD_GET_LAYER = 'layers/%s'
_API_METHOD_MARK_NOTIFICATION_READ = 'notifications/%s'
_API_METHOD_GET_NOTIFICATION = 'notifications/%s'
_API_METHOD_PING = 'metrics'


class SecurityScannerAPI(object):
  """ Helper class for talking to the Security Scan service (Clair). """
  def __init__(self, app, config, storage, client=None, skip_validation=False):
    if not skip_validation:
      config_validator = SecurityConfigValidator(config)
      if not config_validator.valid():
        logger.warning('Invalid config provided to SecurityScannerAPI')
        return

    self._app = app
    self._config = config
    self._instance_keys = InstanceKeys(app)
    self._client = client or config['HTTPCLIENT']
    self._storage = storage
    self._default_storage_locations = config['DISTRIBUTED_STORAGE_PREFERENCE']
    self._target_version = config.get('SECURITY_SCANNER_ENGINE_VERSION_TARGET', 2)


  def _get_image_url_and_auth(self, image):
    """ Returns a tuple of the url and the auth header value that must be used
        to fetch the layer data itself. If the image can't be addressed, we return
        None.
    """
    path = model.storage.get_layer_path(image.storage)
    locations = self._default_storage_locations

    if not self._storage.exists(locations, path):
      locations = get_storage_locations(image.storage.uuid)
      if not locations or not self._storage.exists(locations, path):
        logger.warning('Could not find a valid location to download layer %s.%s out of %s',
                       image.docker_image_id, image.storage.uuid, locations)
        return None, None

    uri = self._storage.get_direct_download_url(locations, path)
    auth_header = None
    if uri is None:
      # Use the registry API instead, with a signed JWT giving access
      repo_name = image.repository.name
      namespace_name = image.repository.namespace_user.username
      repository_and_namespace = '/'.join([namespace_name, repo_name])

      # Generate the JWT which will authorize this
      audience = self._app.config['SERVER_HOSTNAME']
      context, subject = build_context_and_subject(None, None, None)
      access = [{
        'type': 'repository',
        'name': repository_and_namespace,
        'actions': ['pull'],
      }]

      auth_token = generate_bearer_token(audience, subject, context, access,
                                         TOKEN_VALIDITY_LIFETIME_S, self._instance_keys)
      auth_header = 'Bearer ' + auth_token

      with self._app.test_request_context('/'):
        relative_layer_url = url_for('v2.download_blob', repository=repository_and_namespace,
                                     digest=image.storage.content_checksum)
      uri = urljoin(get_app_url(self._config), relative_layer_url)

    return uri, auth_header


  def _new_analyze_request(self, image):
    """ Create the request body to submit the given image for analysis. If the image's URL cannot
        be found, returns None.
    """
    url, auth_header = self._get_image_url_and_auth(image)
    if url is None:
      return None

    layer_request = {
      'Name': '%s.%s' % (image.docker_image_id, image.storage.uuid),
      'Path': url,
      'Format': 'Docker',
    }

    if auth_header is not None:
      layer_request['Headers'] = {
        'Authorization': auth_header,
      }

    if image.parent.docker_image_id and image.parent.storage.uuid:
      layer_request['ParentName'] = '%s.%s' % (image.parent.docker_image_id,
                                               image.parent.storage.uuid)

    return {
      'Layer': layer_request,
    }


  def ping(self):
    """ Calls GET on the metrics endpoint of the security scanner to ensure it is running
        and properly configured. Returns the HTTP response.
    """
    try:
      return self._call('GET', _API_METHOD_PING)
    except requests.exceptions.Timeout:
      logger.exception('Timeout when trying to connect to security scanner endpoint')
      raise Exception('Timeout when trying to connect to security scanner endpoint')
    except requests.exceptions.ConnectionError:
      logger.exception('Connection error when trying to connect to security scanner endpoint')
      raise Exception('Connection error when trying to connect to security scanner endpoint')
    except (requests.exceptions.RequestException, ValueError):
      logger.exception('Exception when trying to connect to security scanner endpoint')
      raise Exception('Exception when trying to connect to security scanner endpoint')


  def analyze_layer(self, layer):
    """ Posts the given layer to the security scanner for analysis, blocking until complete.
        Returns a tuple containing the analysis version (on success, None on failure) and
        whether the request should be retried.
    """
    request = self._new_analyze_request(layer)
    if not request:
      return None, False

    logger.info('Analyzing layer %s', request['Layer']['Name'])
    try:
      response = self._call('POST', _API_METHOD_INSERT, body=request)
      json_response = response.json()
    except requests.exceptions.Timeout:
      logger.exception('Timeout when trying to post layer data response for %s', layer.id)
      return None, True
    except requests.exceptions.ConnectionError:
      logger.exception('Connection error when trying to post layer data response for %s', layer.id)
      return None, True
    except (requests.exceptions.RequestException, ValueError):
      logger.exception('Failed to post layer data response for %s', layer.id)
      return None, False


    # Handle any errors from the security scanner.
    if response.status_code != 201:
      message = json_response.get('Error').get('Message', '')
      logger.warning('A warning event occurred when analyzing layer %s (status code %s): %s',
                     request['Layer']['Name'], response.status_code, message)

      # 400 means the layer could not be analyzed due to a bad request.
      if response.status_code == 400:
        logger.error('Bad request when calling security scanner for layer %s: %s',
                     response.status_code, json_response)
        raise AnalyzeLayerException('Bad request to security scanner')

      # 422 means that the layer could not be analyzed:
      # - the layer could not be extracted (manifest?)
      # - the layer operating system / package manager is unsupported
      return None, response.status_code != 422

    api_version = json_response['Layer']['IndexedByVersion']
    return api_version, False


  def check_layer_vulnerable(self, layer_id, cve_name):
    """ Checks to see if the layer with the given ID is vulnerable to the specified CVE. """
    layer_data = self._get_layer_data(layer_id, include_vulnerabilities=True)
    if layer_data is None or 'Layer' not in layer_data or 'Features' not in layer_data['Layer']:
      return False

    for feature in layer_data['Layer']['Features']:
      for vuln in feature.get('Vulnerabilities', []):
        if vuln['Name'] == cve_name:
          return True

    return False


  def get_notification(self, notification_name, layer_limit=100, page=None):
    """ Gets the data for a specific notification, with optional page token.
        Returns a tuple of the data (None on failure) and whether to retry.
    """
    try:
      params = {
        'limit': layer_limit
      }

      if page is not None:
        params['page'] = page

      response = self._call('GET', _API_METHOD_GET_NOTIFICATION % notification_name, params=params)
      json_response = response.json()
    except requests.exceptions.Timeout:
      logger.exception('Timeout when trying to get notification for %s', notification_name)
      return None, True
    except requests.exceptions.ConnectionError:
      logger.exception('Connection error when trying to get notification for %s', notification_name)
      return None, True
    except (requests.exceptions.RequestException, ValueError):
      logger.exception('Failed to get notification for %s', notification_name)
      return None, False

    if response.status_code != 200:
      return None, response.status_code != 404 and response.status_code != 400

    return json_response, False


  def mark_notification_read(self, notification_name):
    """ Marks a security scanner notification as read. """
    try:
      response = self._call('DELETE', _API_METHOD_MARK_NOTIFICATION_READ % notification_name)
      return response.status_code / 100 == 2
    except requests.exceptions.RequestException:
      logger.exception('Failed to mark notification as read: %s', notification_name)
      return False


  def get_layer_data(self, layer, include_features=False, include_vulnerabilities=False):
    """ Returns the layer data for the specified layer. On error, returns None. """
    layer_id = '%s.%s' % (layer.docker_image_id, layer.storage.uuid)
    return self._get_layer_data(layer_id, include_features, include_vulnerabilities)


  def _get_layer_data(self, layer_id, include_features=False, include_vulnerabilities=False):
    try:
      params = {}
      if include_features:
        params = {'features': True}

      if include_vulnerabilities:
        params = {'vulnerabilities': True}

      response = self._call('GET', _API_METHOD_GET_LAYER % layer_id, params=params)
      logger.debug('Got response %s for vulnerabilities for layer %s',
                   response.status_code, layer_id)
      json_response = response.json()
    except requests.exceptions.Timeout:
      raise APIRequestFailure('API call timed out')
    except requests.exceptions.ConnectionError:
      raise APIRequestFailure('Could not connect to security service')
    except (requests.exceptions.RequestException, ValueError):
      logger.exception('Failed to get layer data response for %s', layer_id)
      raise APIRequestFailure()

    if response.status_code == 404:
      return None

    return json_response


  def _call(self, method, relative_url, params=None, body=None):
    """ Issues an HTTP call to the sec API at the given relative URL.
        This function disconnects from the database while awaiting a response
        from the API server.
    """
    if self._config is None:
      raise Exception('Cannot call unconfigured security system')

    client = self._client
    headers = {'Connection': 'close'}

    timeout = self._config.get('SECURITY_SCANNER_API_TIMEOUT_SECONDS', 10)
    endpoint = self._config['SECURITY_SCANNER_ENDPOINT']
    if method != 'GET':
      timeout = self._config.get('SECURITY_SCANNER_API_BATCH_TIMEOUT_SECONDS', timeout)
      endpoint = self._config.get('SECURITY_SCANNER_ENDPOINT_BATCH') or endpoint

    api_url = urljoin(endpoint, '/' + self._config.get('SECURITY_SCANNER_API_VERSION', 'v1')) + '/'
    url = urljoin(api_url, relative_url)
    signer_proxy_url = self._config.get('JWTPROXY_SIGNER', 'localhost:8080')

    with CloseForLongOperation(self._config):
      logger.debug('%sing security URL %s', method.upper(), url)
      return client.request(method, url, json=body, params=params, timeout=timeout,
                            verify='/conf/mitm.cert', headers=headers,
                            proxies={
                              'https': 'https://' + signer_proxy_url,
                              'http': 'http://' + signer_proxy_url
                            })