Files
GoogleDriveManagement/src/gam/auth/signjwt.py
2023-04-10 12:18:56 -04:00

100 lines
3.4 KiB
Python

''' Use Google Application Default Credentials '''
import datetime
import json
import google.auth
from google.auth._helpers import datetime_to_secs, scopes_to_string, utcnow
import google.oauth2.service_account
import gam
from gam import controlflow
from gam import gapi
from gam import transport
from gam.var import GM_Globals, GM_CACHE_DIR
_DEFAULT_TOKEN_LIFETIME_SECS = 3600 # 1 hour in seconds
_GOOGLE_OAUTH2_TOKEN_ENDPOINT = "https://oauth2.googleapis.com/token"
_IAM_SCOPES = ['https://www.googleapis.com/auth/iam']
# Some Workforce Identity Federation endpoints such as GitHub Actions
# only allow TLS 1.2 as of April 2023.
def get_request():
httpc = transport.create_http(override_min_tls='TLSv1_2')
return transport.create_request(httpc)
class JWTCredentials(google.auth.jwt.Credentials):
''' Class used for DASA '''
def _make_jwt(self):
now = utcnow()
lifetime = datetime.timedelta(seconds=self._token_lifetime)
expiry = now + lifetime
payload = {
"iss": self._issuer,
"sub": self._subject,
"iat": datetime_to_secs(now),
"exp": datetime_to_secs(expiry),
}
if self._audience:
payload["aud"] = self._audience
payload.update(self._additional_claims)
jwt = self._signer.sign(payload)
return jwt, expiry
class Credentials(google.oauth2.service_account.Credentials):
''' Class used for DwD '''
def _make_authorization_grant_assertion(self):
now = utcnow()
lifetime = datetime.timedelta(seconds=_DEFAULT_TOKEN_LIFETIME_SECS)
expiry = now + lifetime
payload = {
"iat": datetime_to_secs(now),
"exp": datetime_to_secs(expiry),
"iss": self._service_account_email,
"aud": _GOOGLE_OAUTH2_TOKEN_ENDPOINT,
"scope": scopes_to_string(self._scopes or ()),
}
payload.update(self._additional_claims)
# The subject can be a user email for domain-wide delegation.
if self._subject:
payload.setdefault("sub", self._subject)
token = self._signer(payload)
return token
class SignJwt(google.auth.crypt.Signer):
''' Signer class for SignJWT '''
def __init__(self, service_account_info):
self.service_account_email = service_account_info['client_email']
self.name = f'projects/-/serviceAccounts/{self.service_account_email}'
self._key_id = None
@property # type: ignore
def key_id(self):
return self._key_id
def sign(self, message):
''' Call IAM Credentials SignJWT API to get our signed JWT '''
request = get_request()
try:
credentials, _ = google.auth.default(scopes=_IAM_SCOPES,
request=request)
except (google.auth.exceptions.DefaultCredentialsError,
google.auth.exceptions.RefreshError) as e:
controlflow.system_error_exit(2, e)
httpObj = transport.AuthorizedHttp(
credentials,
transport.create_http(cache=GM_Globals[GM_CACHE_DIR]))
iamc = gam.getService('iamcredentials', httpObj)
response = gapi.call(iamc.projects().serviceAccounts(),
'signJwt',
name=self.name,
body={'payload': json.dumps(message)})
signed_jwt = response.get('signedJwt')
return signed_jwt