import logging
from urlparse import urljoin
import requests
from flask import url_for
from data.database import CloseForLongOperation
from data import model
from data.model.storage import get_storage_locations
from util.failover import failover, FailoverException
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
UNKNOWN_PARENT_LAYER_ERROR_MSG = 'worker: parent layer is unknown, it must be processed first'
MITM_CERT_PATH = '/conf/mitm.cert'
DEFAULT_HTTP_HEADERS = {'Connection': 'close'}
logger = logging.getLogger(__name__)
class AnalyzeLayerException(Exception):
""" Exception raised when a layer fails to analyze due to a request issue. """
class AnalyzeLayerRetryException(Exception):
""" Exception raised when a layer fails to analyze due to a request issue, and the request should
be retried.
"""
class MissingParentLayerException(AnalyzeLayerException):
""" Exception raised when the parent of the layer is missing from the security scanner. """
class InvalidLayerException(AnalyzeLayerException):
""" Exception raised when the layer itself cannot be handled by the security scanner. """
class APIRequestFailure(Exception):
""" Exception raised when there is a failure to conduct an API request. """
class Non200ResponseException(Exception):
""" Exception raised when the upstream API returns a non-200 HTTP status code. """
def __init__(self, response):
super(Non200ResponseException, self).__init__()
self.response = response
_API_METHOD_INSERT = 'layers'
_API_METHOD_GET_LAYER = 'layers/%s'
_API_METHOD_DELETE_LAYER = 'layers/%s'
_API_METHOD_MARK_NOTIFICATION_READ = 'notifications/%s'
_API_METHOD_GET_NOTIFICATION = 'notifications/%s'
_API_METHOD_PING = 'metrics'
def compute_layer_id(layer):
""" Returns the ID for the layer in the security scanner. """
return '%s.%s' % (layer.docker_image_id, layer.storage.uuid)
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 out of %s',
compute_layer_id(image), 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, layer):
""" Create the request body to submit the given layer for analysis. If the layer's URL cannot
be found, returns None.
"""
url, auth_header = self._get_image_url_and_auth(layer)
if url is None:
return None
layer_request = {
'Name': compute_layer_id(layer),
'Path': url,
'Format': 'Docker',
}
if auth_header is not None:
layer_request['Headers'] = {
'Authorization': auth_header,
}
if layer.parent.docker_image_id and layer.parent.storage.uuid:
layer_request['ParentName'] = compute_layer_id(layer.parent)
return {
'Layer': layer_request,
}
def cleanup_layers(self, layers):
""" Callback invoked by garbage collection to cleanup any layers that no longer
need to be stored in the security scanner.
"""
if self._config is None:
# Security scanner not enabled.
return
for layer in layers:
self.delete_layer(layer)
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 delete_layer(self, layer):
""" Calls DELETE on the given layer in the security scanner, removing it from
its database.
"""
layer_id = compute_layer_id(layer)
try:
self._call('DELETE', _API_METHOD_DELETE_LAYER % layer_id)
return True
except Non200ResponseException:
return False
except requests.exceptions.RequestException:
logger.exception('Failed to delete layer: %s', layer_id)
return False
def analyze_layer(self, layer):
""" Posts the given layer to the security scanner for analysis, blocking until complete.
Returns the analysis version on success or raises an exception deriving from
AnalyzeLayerException on failure. Callers should handle all cases of AnalyzeLayerException.
"""
def _response_json(request, response):
try:
return response.json()
except ValueError:
logger.exception('Failed to decode JSON when analyzing layer %s', request['Layer']['Name'])
raise AnalyzeLayerException
request = self._new_analyze_request(layer)
if not request:
raise AnalyzeLayerException
logger.info('Analyzing layer %s', request['Layer']['Name'])
try:
response = self._call('POST', _API_METHOD_INSERT, body=request)
except requests.exceptions.Timeout:
logger.exception('Timeout when trying to post layer data response for %s', layer.id)
raise AnalyzeLayerRetryException
except requests.exceptions.ConnectionError:
logger.exception('Connection error when trying to post layer data response for %s', layer.id)
raise AnalyzeLayerRetryException
except (requests.exceptions.RequestException) as re:
logger.exception('Failed to post layer data response for %s: %s', layer.id, re)
raise AnalyzeLayerException
except Non200ResponseException as ex:
message = _response_json(request, ex.response).get('Error').get('Message', '')
logger.warning('A warning event occurred when analyzing layer %s (status code %s): %s',
request['Layer']['Name'], ex.response.status_code, message)
# 400 means the layer could not be analyzed due to a bad request.
if ex.response.status_code == 400:
if message == UNKNOWN_PARENT_LAYER_ERROR_MSG:
raise MissingParentLayerException('Bad request to security scanner: %s' % message)
else:
raise AnalyzeLayerException('Bad request to security scanner: %s' % message)
# 422 means that the layer could not be analyzed:
# - the layer could not be extracted (might be a manifest or an invalid .tar.gz)
# - the layer operating system / package manager is unsupported
elif ex.response.status_code == 422:
raise InvalidLayerException
# Otherwise, it is some other error and we should retry.
raise AnalyzeLayerRetryException
# Return the parsed API version.
return _response_json(request, response)['Layer']['IndexedByVersion']
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
except Non200ResponseException as ex:
return None, ex.response.status_code != 404 and ex.response.status_code != 400
return json_response, False
def mark_notification_read(self, notification_name):
""" Marks a security scanner notification as read. """
try:
self._call('DELETE', _API_METHOD_MARK_NOTIFICATION_READ % notification_name)
return True
except Non200ResponseException:
return False
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 = compute_layer_id(layer)
return self._get_layer_data(layer_id, include_features, include_vulnerabilities)
def _get_layer_data(self, layer_id, include_features=False, include_vulnerabilities=False):
params = {}
if include_features:
params = {'features': True}
if include_vulnerabilities:
params = {'vulnerabilities': True}
try:
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)
except Non200ResponseException as ex:
logger.debug('Got failed response %s for vulnerabilities for layer %s',
ex.response.status_code, layer_id)
if ex.response.status_code == 404:
return None
elif ex.response.status_code // 100 == 5:
logger.error(
'downstream security service failure: status %d, text: %s',
ex.response.status_code,
ex.response.text,
)
raise APIRequestFailure('Downstream service returned 5xx')
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:
logger.exception('Failed to get layer data response for %s', layer_id)
raise APIRequestFailure()
try:
return response.json()
except ValueError:
logger.exception('Failed to decode response JSON')
def _request(self, method, endpoint, path, body, params, timeout):
""" Issues an HTTP request to the security endpoint. """
if self._config is None:
raise Exception('Cannot call unconfigured security system')
url = _join_api_url(endpoint, self._config.get('SECURITY_SCANNER_API_VERSION', 'v1'), path)
signer_proxy_url = self._config.get('JWTPROXY_SIGNER', 'localhost:8080')
logger.debug('%sing security URL %s', method.upper(), url)
resp = self._client.request(method, url, json=body, params=params, timeout=timeout,
verify=MITM_CERT_PATH, headers=DEFAULT_HTTP_HEADERS,
proxies={'https': 'https://' + signer_proxy_url,
'http': 'http://' + signer_proxy_url})
if resp.status_code // 100 != 2:
raise Non200ResponseException(resp)
return resp
def _call(self, method, path, params=None, body=None):
""" Issues an HTTP request to the security endpoint handling the logic of using an alternative
BATCH endpoint for non-GET requests and failover for GET requests.
"""
if self._config is None:
raise Exception('Cannot call unconfigured security system')
timeout = self._config.get('SECURITY_SCANNER_API_TIMEOUT_SECONDS', 1)
endpoint = self._config['SECURITY_SCANNER_ENDPOINT']
with CloseForLongOperation(self._config):
# If the request isn't a read, attempt to use a batch stack and do not fail over.
if method != 'GET':
if self._config.get('SECURITY_SCANNER_ENDPOINT_BATCH') is not None:
endpoint = self._config['SECURITY_SCANNER_ENDPOINT_BATCH']
timeout = self._config.get('SECURITY_SCANNER_API_BATCH_TIMEOUT_SECONDS') or timeout
return self._request(method, endpoint, path, body, params, timeout)
# The request is read-only and can failover.
all_endpoints = [endpoint] + self._config.get('SECURITY_SCANNER_READONLY_FAILOVER_ENDPOINTS', [])
return _failover_read_request(*[((self._request, endpoint, path, body, params, timeout), {})
for endpoint in all_endpoints])
def _join_api_url(endpoint, api_version, path):
pathless_url = urljoin(endpoint, '/' + api_version) + '/'
return urljoin(pathless_url, path)
@failover
def _failover_read_request(request_fn, endpoint, path, body, params, timeout):
""" This function auto-retries read-only requests until they return a 2xx status code. """
try:
return request_fn('GET', endpoint, path, body, params, timeout)
except (requests.exceptions.RequestException, Non200ResponseException) as ex:
raise FailoverException(ex)