Use the instance service key for registry JWT signing

util/security/instancekeys.py

@@ -0,0 +1,81 @@
+from cachetools import lru_cache
+from data import model
+from util.expiresdict import ExpiresDict, ExpiresEntry
+from util.security import jwtutil
+
+
+class InstanceKeys(object):
+  """ InstanceKeys defines a helper class for interacting with the Quay instance service keys
+      used for JWT signing of registry tokens as well as requests from Quay to other services
+      such as Clair. Each container will have a single registered instance key.
+  """
+  def __init__(self, app):
+    self.app = app
+    self.instance_keys = ExpiresDict(self._load_instance_keys)
+    self.public_keys = {}
+
+  def clear_cache(self):
+    """ Clears the cache of instance keys. """
+    self.instance_keys = ExpiresDict(self._load_instance_keys)
+    self.public_keys = {}
+
+  def _load_instance_keys(self):
+    # Load all the instance keys.
+    keys = {}
+    for key in model.service_keys.list_service_keys(self.service_name):
+      keys[key.kid] = ExpiresEntry(key, key.expiration_date)
+
+    # Remove any expired or deleted keys from the public keys cache.
+    for key in self.public_keys:
+      if key not in keys:
+        self.public_keys.pop(key)
+
+    return keys
+
+  @property
+  def service_name(self):
+    """ Returns the name of the instance key's service (i.e. 'quay'). """
+    return self.app.config['INSTANCE_SERVICE_KEY_SERVICE']
+
+  @property
+  def service_key_expiration(self):
+    """ Returns the defined expiration for instance service keys, in minutes. """
+    return self.app.config.get('INSTANCE_SERVICE_KEY_EXPIRATION', 120)
+
+  @property
+  @lru_cache(maxsize=1)
+  def local_key_id(self):
+    """ Returns the ID of the local instance service key. """
+    return _load_file_contents(self.app.config['INSTANCE_SERVICE_KEY_KID_LOCATION'])
+
+  @property
+  @lru_cache(maxsize=1)
+  def local_private_key(self):
+    """ Returns the private key of the local instance service key. """
+    return _load_file_contents(self.app.config['INSTANCE_SERVICE_KEY_LOCATION'])
+
+  def get_service_key_public_key(self, kid):
+    """ Returns the public key associated with the given instance service key or None if none. """
+
+    # Note: We do the lookup via instance_keys *first* to ensure that if a key has expired, we
+    # don't use the entry in the public key cache.
+    service_key = self.instance_keys.get(kid)
+    if service_key is None:
+      # Remove the kid from the cache just to be sure.
+      self.public_keys.pop(kid, None)
+      return None
+
+    public_key = self.public_keys.get(kid)
+    if public_key is not None:
+      return public_key
+
+    # Convert the JWK into a public key and cache it (since the conversion can take > 200ms).
+    public_key = jwtutil.jwk_dict_to_public_key(service_key.jwk)
+    self.public_keys[kid] = public_key
+    return public_key
+
+
+def _load_file_contents(path):
+  """ Returns the contents of the specified file path. """
+  with open(path) as f:
+    return f.read()

util/security/jwtutil.py

@@ -1,3 +1,5 @@
+import re
+
 from datetime import datetime, timedelta
 from jwt import PyJWT
 from jwt.exceptions import (
@@ -5,8 +7,19 @@ from jwt.exceptions import (
   ImmatureSignatureError, InvalidIssuedAtError, InvalidIssuerError, MissingRequiredClaimError
 )
 
+from cryptography.hazmat.backends import default_backend
+from cryptography.hazmat.primitives.asymmetric.ec import EllipticCurvePublicNumbers
+from cryptography.hazmat.primitives.asymmetric.rsa import RSAPublicNumbers
+from jwkest.jwk import keyrep, RSAKey, ECKey
+
+
+# TOKEN_REGEX defines a regular expression for matching JWT bearer tokens.
+TOKEN_REGEX = re.compile(r'\ABearer (([a-zA-Z0-9+\-_/]+\.)+[a-zA-Z0-9+\-_/]+)\Z')
+
 
 class StrictJWT(PyJWT):
+  """ StrictJWT defines a JWT decoder with extra checks. """
+
   @staticmethod
   def _get_default_options():
     # Weird syntax to call super on a staticmethod
@@ -53,3 +66,16 @@ def exp_max_s_option(max_exp_s):
 
 
 decode = StrictJWT().decode
+
+
+def jwk_dict_to_public_key(jwk):
+  """ Converts the specified JWK into a public key. """
+  jwkest_key = keyrep(jwk)
+  if isinstance(jwkest_key, RSAKey):
+    pycrypto_key = jwkest_key.key
+    return RSAPublicNumbers(e=pycrypto_key.e, n=pycrypto_key.n).public_key(default_backend())
+  elif isinstance(jwkest_key, ECKey):
+    x, y = jwkest_key.get_key()
+    return EllipticCurvePublicNumbers(x, y, jwkest_key.curve).public_key(default_backend())
+
+  raise Exception('Unsupported kind of JWK: %s', str(type(jwkest_key)))

util/security/registry_jwt.py

@@ -1,17 +1,80 @@
 import time
 import jwt
+import logging
 
-from cachetools import lru_cache
+from util.security import jwtutil
 
+logger = logging.getLogger(__name__)
 
 ANONYMOUS_SUB = '(anonymous)'
+ALGORITHM = 'RS256'
 
 
-def generate_jwt_object(audience, subject, context, access, lifetime_s, app_config):
-  """ Generates a compact encoded JWT with the values specified.
+class InvalidBearerTokenException(Exception):
+  pass
+
+
+def decode_bearer_token(bearer_token, instance_keys):
+  """ decode_bearer_token decodes the given bearer token that contains both a Key ID as well as the
+      encoded JWT and returns the decoded and validated JWT. On any error, raises an
+      InvalidBearerTokenException with the reason for failure.
   """
+  app_config = instance_keys.app.config
+
+  # Extract the jwt token from the header
+  match = jwtutil.TOKEN_REGEX.match(bearer_token)
+  if match is None:
+    raise InvalidBearerTokenException('Invalid bearer token format')
+
+  encoded_jwt = match.group(1)
+  logger.debug('encoded JWT: %s', encoded_jwt)
+
+  # Decode the key ID.
+  headers = jwt.get_unverified_header(encoded_jwt)
+  kid = headers.get('kid', None)
+  if kid is None:
+    logger.error('Missing kid header on encoded JWT: %s', encoded_jwt)
+    raise InvalidBearerTokenException('Missing kid header')
+
+  # Find the matching public key.
+  public_key = instance_keys.get_service_key_public_key(kid)
+  if public_key is None:
+    logger.error('Could not find requested service key %s', kid)
+    raise InvalidBearerTokenException('Unknown service key')
+
+  # Load the JWT returned.
+  try:
+    expected_issuer = instance_keys.service_name
+    audience = app_config['SERVER_HOSTNAME']
+    max_signed_s = app_config.get('REGISTRY_JWT_AUTH_MAX_FRESH_S', 3660)
+
+    max_exp = jwtutil.exp_max_s_option(max_signed_s)
+    payload = jwtutil.decode(encoded_jwt, public_key, algorithms=[ALGORITHM], audience=audience,
+                             issuer=expected_issuer, options=max_exp)
+  except jwtutil.InvalidTokenError as ite:
+    logger.exception('Invalid token reason: %s', ite)
+    raise InvalidBearerTokenException(ite)
+
+  if not 'sub' in payload:
+    raise InvalidBearerTokenException('Missing sub field in JWT')
+
+  return payload
+
+
+def generate_bearer_token(audience, subject, context, access, lifetime_s, instance_keys):
+  """ Generates a registry bearer token (without the 'Bearer ' portion) based on the given
+      information.
+  """
+  return _generate_jwt_object(audience, subject, context, access, lifetime_s,
+                              instance_keys.service_name, instance_keys.local_key_id,
+                              instance_keys.local_private_key)
+
+
+def _generate_jwt_object(audience, subject, context, access, lifetime_s, issuer, key_id,
+                         private_key):
+  """ Generates a compact encoded JWT with the values specified. """
   token_data = {
-    'iss': app_config['JWT_AUTH_TOKEN_ISSUER'],
+    'iss': issuer,
     'aud': audience,
     'nbf': int(time.time()),
     'iat': int(time.time()),
@@ -21,15 +84,11 @@ def generate_jwt_object(audience, subject, context, access, lifetime_s, app_conf
     'context': context,
   }
 
-  certificate = _load_certificate_bytes(app_config['JWT_AUTH_CERTIFICATE_PATH'])
-
   token_headers = {
-    'x5c': [certificate],
+    'kid': key_id,
   }
 
-  private_key = _load_private_key(app_config['JWT_AUTH_PRIVATE_KEY_PATH'])
-
-  return jwt.encode(token_data, private_key, 'RS256', headers=token_headers)
+  return jwt.encode(token_data, private_key, ALGORITHM, headers=token_headers)
 
 
 def build_context_and_subject(user, token, oauthtoken):
@@ -64,14 +123,3 @@ def build_context_and_subject(user, token, oauthtoken):
   return (context, ANONYMOUS_SUB)
 
 
-@lru_cache(maxsize=1)
-def _load_certificate_bytes(certificate_file_path):
-  with open(certificate_file_path) as cert_file:
-    cert_lines = cert_file.readlines()[1:-1]
-    return ''.join([cert_line.rstrip('\n') for cert_line in cert_lines])
-
-
-@lru_cache(maxsize=1)
-def _load_private_key(private_key_file_path):
-  with open(private_key_file_path) as private_key_file:
-    return private_key_file.read()