OpenStack Identity (keystone)

Comment 0 for bug 1129713

Revision history for this message

Adam Young (ayoung) wrote on 2013-02-19: Validation of PKI tokens bypasses revocation check

for PKI tokens, we are bypassing token.get_token() call and therefore skipping the “valid=True” check.

In Grizzly, this code is in keystone/token/controllers.py
In Folsom, this code is in keystone/service.py

The if block bypasses the backend check. It is in the backend where tokens are checked for revocation.

def _get_token_ref(self, context, token_id, belongs_to=None):
"""Returns a token if a valid one exists.

Optionally, limited to a token owned by a specific tenant.

"""
# TODO(termie): this stuff should probably be moved to middleware
self.assert_admin(context)

        if cms.is_ans1_token(token_id):
            data = json.loads(cms.cms_verify(cms.token_to_cms(token_id),
                                             CONF.signing.certfile,
                                             CONF.signing.ca_certs))
            data['access']['token']['user'] = data['access']['user']
            data['access']['token']['metadata'] = data['access']['metadata']
            if belongs_to:
                assert data['access']['token']['tenant']['id'] == belongs_to
            token_ref = data['access']['token']
        else:
            token_ref = self.token_api.get_token(context=context,
                                                 token_id=token_id)
        return token_ref

The exposure is limited to people that are passing the whole PKI token back for validation via the web service.

This PKI tokens were supposed to be validated primarily via Crypto, but there is an option to validate them against the live server as well. It is only this last code path that is affected. It is unlikely to be triggered in Folsom, as people have to make a deliberate decision to use PKI tokens, and are unlikely to be validating them against the Keystone server.

Remote services can choose to pass a Hash of the PKI token to the validate Web API, which web services are likely to do, as the Hash is short enough to fit in a cookie. The Hash is then it looked up using the backend get_token() behavior and works correctly.

It does not effect the keystone calls that first require validating the token. For example if a user runs tenant_list against their own account, using a PKI token, they do

token_ref = self.token_api.get_token(context=context,
token_id=context['token_id'])

This was discovered by Guang Yee.

for PKI tokens, we are bypassing token.get_token() call and therefore skipping the “valid=True” check.

In Grizzly, this code is in keystone/token/controllers.py
In Folsom, this code is in keystone/service.py

The if block bypasses the backend  check.  It is in the backend where tokens are checked for revocation.

def _get_token_ref(self, context, token_id, belongs_to=None):
        """Returns a token if a valid one exists.

Optionally, limited to a token owned by a specific tenant.

"""
        # TODO(termie): this stuff should probably be moved to middleware
        self.assert_admin(context)

The exposure is limited to people that are passing the whole PKI token back for validation via the web service.

This PKI tokens were supposed to be validated primarily via Crypto, but there is an option to validate them against the live server as well.  It is only this last code path that is affected.   It is unlikely to be triggered in Folsom, as people have to make a deliberate decision to  use PKI tokens, and  are unlikely to be validating them against the Keystone server.

Remote services can choose to pass a Hash of the PKI token to the validate Web API, which web services are likely to do, as the Hash is short enough to fit in a cookie.  The Hash is then it looked up using  the backend get_token()  behavior and works correctly.

It does not effect the keystone calls that first require validating the token.  For example if a user runs tenant_list against their own account, using a PKI token, they do

token_ref = self.token_api.get_token(context=context,
                                                 token_id=context['token_id'])

This was discovered by Guang Yee.