diff --git a/.zuul.yaml b/.zuul.yaml new file mode 100644 index 0000000..d6eabe9 --- /dev/null +++ b/.zuul.yaml @@ -0,0 +1,53 @@ +# Image building jobs +- secret: + name: gcp-authdaemon-dockerhub + data: + username: zuulzuul + password: !encrypted/pkcs1-oaep + - HRBNCurib3EWbZJ7ZT7qHXZJVWBz83OWdebBDGTJKShdh9BO3yfBYws48YYDx3D3+U/ZA + JvagyvXu4faFEQrAyKg+MwYrGKfak7u+daOeNYsPtETpYfvPGb1h09cXUX8eMVqtzNket + BMXg/KcoGJwGwpvkYlMG/DhnqoTZ48LQs3V8B499uSWYizJHTnetgoGk15trE1Z90xaoZ + r/cj/KbRs4NGiFLkdLX7L0RXgZG68HHfCpdTgCyUtoqjaC3nWIAqX9wqCwBq++T9ye8Dl + XAhIbyouYLDuZFwywupiv4dJhpea8F0PRVYv/uDf63x1lj8+Ga/SN+fK1NZrf/s44oH3W + R0oD95B/hq+QiRSRzzL/3SxnsHzLAoal21UHwa+BQrGCyr0ggKkVLx+y0SMHOZeLV7vb8 + XmCwaP7/LvJKIH/hggLsaleYlUlgJ6uyXmgbQl0yLPI3w8q8aRGLkXfAqBNFKqwprUU7l + +nyExeVe1XfkyloOkk7GL6tdG6g9Sj3A1hYxshACF9+irra5cgYzNi4U3shTBvmdf3tK9 + 5Bh4ePAgwh4S+lgXcmtd7Li9nBhkobNPC1VbDZigV14c04Juep10Y3O2wbFgOY/znG6d8 + c8y81M5qEpjJn7pmJ0WsGH+g8oH+jdVKTNS70ZRsaQQijaDigNMb56CbQIc+xc= + +- job: + name: gcp-authdaemon-build-image + parent: opendev-build-docker-image + vars: &gcp_authdaemon_image_vars + docker_images: + - context: . + repository: zuul/gcp-authdaemon + +- job: + name: gcp-authdaemon-upload-image + parent: opendev-upload-docker-image + vars: *gcp_authdaemon_image_vars + secrets: + name: docker_credentials + secret: gcp-authdaemon-dockerhub + pass-to-parent: true + +- job: + name: gcp-authdaemon-promote-image + parent: opendev-promote-docker-image + vars: *gcp_authdaemon_image_vars + secrets: + name: docker_credentials + secret: gcp-authdaemon-dockerhub + pass-to-parent: true + +- project: + check: + jobs: + - gcp-authdaemon-build-image + gate: + jobs: + - gcp-authdaemon-upload-image + promote: + jobs: + - gcp-authdaemon-promote-image diff --git a/Dockerfile b/Dockerfile new file mode 100644 index 0000000..0855177 --- /dev/null +++ b/Dockerfile @@ -0,0 +1,6 @@ +FROM docker.io/opendevorg/python-base + +COPY authdaemon.py / + +ENTRYPOINT ["/authdaemon.py"] +CMD ["/authdaemon/token"] diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..75b5248 --- /dev/null +++ b/LICENSE @@ -0,0 +1,202 @@ + + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright [yyyy] [name of copyright owner] + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/README b/README new file mode 100644 index 0000000..a3a2c49 --- /dev/null +++ b/README @@ -0,0 +1,18 @@ +An authorization daemon for Google Cloud. + +This repo builds a container image which runs a special-purpose +authorization daemon. It is intended to be run in Google Cloud +(particularly in Google Kubernetes Engine). The daemon periodically +fetches a bearer token from the Google Cloud metadata service and +writes it to a location on disk. + +Running Zuul in GKE with access to service account credentials can be +complicated because the executor does not limit access to the URLs +from which they are fetched. This means that, without a solution such +as this, even untrusted jobs may be able to access these credentials. + +However, with this daemon, Zuul may be configured to run in GKE with +Workload Identity enabled so that the executor does not have access to +service account credentials. This daemon may be run with access to +credentials and will fetch them write them to a shared volume that may +then be exposed by the executor to trusted (but not untrusted) jobs. diff --git a/authdaemon.py b/authdaemon.py new file mode 100755 index 0000000..2153641 --- /dev/null +++ b/authdaemon.py @@ -0,0 +1,111 @@ +#!/usr/bin/env python +# Copyright (C) 2012 Google Inc. +# Copyright (C) 2019 Red Hat, Inc. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +""" +Background daemon to refresh OAuth access tokens. +Tokens are written to the pathname supplied. + +Runs only on Google Compute Engine (GCE). +""" + +from __future__ import print_function + +import atexit +import contextlib +import json +import os +import platform +import subprocess +import sys +import time +import urllib.request +import urllib.error + + +REFRESH = 25 # seconds remaining when starting refresh +RETRY_INTERVAL = 5 # seconds between retrying a failed refresh +META_URL = 'http://metadata.google.internal/computeMetadata/v1/instance/service-accounts/default/' +SUPPORTED_SCOPES = [ + 'https://www.googleapis.com/auth/cloud-platform', +] + + +def read_meta(part): + r = urllib.request.Request(META_URL + part) + r.add_header('Metadata-Flavor', 'Google') + return contextlib.closing(urllib.request.urlopen(r)) + + +def select_scope(): + with read_meta('scopes') as d: + data = d.read().decode('utf8') + avail = set(data.split()) + scopes = [s for s in SUPPORTED_SCOPES if s in avail] + if scopes: + return scopes[0] + sys.stderr.write('error: VM must have one of these scopes:\n\n') + for s in SUPPORTED_SCOPES: + sys.stderr.write(' %s\n' % (s)) + sys.exit(1) + + +def acquire_token(scope, retry): + while True: + try: + with read_meta('token?scopes=' + scope) as d: + return json.load(d) + except urllib.error.URLError: + if not retry: + raise + time.sleep(RETRY_INTERVAL) + + +def update_cookie(scope, retry): + now = int(time.time()) + token = acquire_token(scope, retry) + access_token = token['access_token'] + expires = now + int(token['expires_in']) # Epoch in sec + path = sys.argv[1] + tmp_path = path + ".lock" + with open(tmp_path, 'w') as f: + f.write(json.dumps(token)) + print('Updating %s.' % path) + print('Expires: %d, %s, in %d seconds'% ( + expires, time.ctime(expires), expires - now)) + sys.stdout.flush() + os.rename(tmp_path, path) + return expires + + +def refresh_loop(scope, expires): + expires = expires - REFRESH + while True: + now = time.time() + expires = max(expires, now + RETRY_INTERVAL) + while now < expires: + time.sleep(expires - now) + now = time.time() + expires = update_cookie(scope, retry=True) - REFRESH + + +def main(): + scope = select_scope() + expires = update_cookie(scope, retry=False) + refresh_loop(scope, expires) + + +if __name__ == '__main__': + main()