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feat(storage): add support for signing URLs using token (#9889)
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* feat(storage): add support for signing URLs using token

* feat(bigquery): add system tests for the feature

* feat(storage): add iam dependency in nox file and cosmetic changes
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HemangChothani authored Jan 30, 2020
1 parent 7c87dab commit e710547
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Showing 6 changed files with 207 additions and 9 deletions.
87 changes: 82 additions & 5 deletions storage/google/cloud/storage/_signing.py
Original file line number Diff line number Diff line change
Expand Up @@ -19,10 +19,14 @@
import datetime
import hashlib
import re
import json

import six

import google.auth.credentials

from google.auth import exceptions
from google.auth.transport import requests
from google.cloud import _helpers


Expand Down Expand Up @@ -265,6 +269,8 @@ def generate_signed_url_v2(
generation=None,
headers=None,
query_parameters=None,
service_account_email=None,
access_token=None,
):
"""Generate a V2 signed URL to provide query-string auth'n to a resource.
Expand Down Expand Up @@ -340,6 +346,12 @@ def generate_signed_url_v2(
Requests using the signed URL *must* pass the specified header
(name and value) with each request for the URL.
:type service_account_email: str
:param service_account_email: (Optional) E-mail address of the service account.
:type access_token: str
:param access_token: (Optional) Access token for a service account.
:type query_parameters: dict
:param query_parameters:
(Optional) Additional query paramtersto be included as part of the
Expand Down Expand Up @@ -370,9 +382,17 @@ def generate_signed_url_v2(
string_to_sign = "\n".join(elements_to_sign)

# Set the right query parameters.
signed_query_params = get_signed_query_params_v2(
credentials, expiration_stamp, string_to_sign
)
if access_token and service_account_email:
signature = _sign_message(string_to_sign, access_token, service_account_email)
signed_query_params = {
"GoogleAccessId": service_account_email,
"Expires": str(expiration),
"Signature": signature,
}
else:
signed_query_params = get_signed_query_params_v2(
credentials, expiration_stamp, string_to_sign
)

if response_type is not None:
signed_query_params["response-content-type"] = response_type
Expand Down Expand Up @@ -409,6 +429,8 @@ def generate_signed_url_v4(
generation=None,
headers=None,
query_parameters=None,
service_account_email=None,
access_token=None,
_request_timestamp=None, # for testing only
):
"""Generate a V4 signed URL to provide query-string auth'n to a resource.
Expand Down Expand Up @@ -492,6 +514,12 @@ def generate_signed_url_v4(
signed URLs. See:
https://cloud.google.com/storage/docs/xml-api/reference-headers#query
:type service_account_email: str
:param service_account_email: (Optional) E-mail address of the service account.
:type access_token: str
:param access_token: (Optional) Access token for a service account.
:raises: :exc:`TypeError` when expiration is not a valid type.
:raises: :exc:`AttributeError` if credentials is not an instance
of :class:`google.auth.credentials.Signing`.
Expand Down Expand Up @@ -583,9 +611,58 @@ def generate_signed_url_v4(
]
string_to_sign = "\n".join(string_elements)

signature_bytes = credentials.sign_bytes(string_to_sign.encode("ascii"))
signature = binascii.hexlify(signature_bytes).decode("ascii")
if access_token and service_account_email:
signature = _sign_message(string_to_sign, access_token, service_account_email)
signature_bytes = base64.b64decode(signature)
signature = binascii.hexlify(signature_bytes).decode("ascii")
else:
signature_bytes = credentials.sign_bytes(string_to_sign.encode("ascii"))
signature = binascii.hexlify(signature_bytes).decode("ascii")

return "{}{}?{}&X-Goog-Signature={}".format(
api_access_endpoint, resource, canonical_query_string, signature
)


def _sign_message(message, access_token, service_account_email):

"""Signs a message.
:type message: str
:param message: The message to be signed.
:type access_token: str
:param access_token: Access token for a service account.
:type service_account_email: str
:param service_account_email: E-mail address of the service account.
:raises: :exc:`TransportError` if an `access_token` is unauthorized.
:rtype: str
:returns: The signature of the message.
"""
message = _helpers._to_bytes(message)

method = "POST"
url = "https://iam.googleapis.com/v1/projects/-/serviceAccounts/{}:signBlob?alt=json".format(
service_account_email
)
headers = {
"Authorization": "Bearer " + access_token,
"Content-type": "application/json",
}
body = json.dumps({"bytesToSign": base64.b64encode(message).decode("utf-8")})

request = requests.Request()
response = request(url=url, method=method, body=body, headers=headers)

if response.status != six.moves.http_client.OK:
raise exceptions.TransportError(
"Error calling the IAM signBytes API: {}".format(response.data)
)

data = json.loads(response.data.decode("utf-8"))
return data["signature"]
10 changes: 10 additions & 0 deletions storage/google/cloud/storage/blob.py
Original file line number Diff line number Diff line change
Expand Up @@ -358,6 +358,8 @@ def generate_signed_url(
client=None,
credentials=None,
version=None,
service_account_email=None,
access_token=None,
):
"""Generates a signed URL for this blob.
Expand Down Expand Up @@ -445,6 +447,12 @@ def generate_signed_url(
:param version: (Optional) The version of signed credential to create.
Must be one of 'v2' | 'v4'.
:type service_account_email: str
:param service_account_email: (Optional) E-mail address of the service account.
:type access_token: str
:param access_token: (Optional) Access token for a service account.
:raises: :exc:`ValueError` when version is invalid.
:raises: :exc:`TypeError` when expiration is not a valid type.
:raises: :exc:`AttributeError` if credentials is not an instance
Expand Down Expand Up @@ -497,6 +505,8 @@ def generate_signed_url(
generation=generation,
headers=headers,
query_parameters=query_parameters,
service_account_email=service_account_email,
access_token=access_token,
)

def exists(self, client=None):
Expand Down
2 changes: 1 addition & 1 deletion storage/noxfile.py
Original file line number Diff line number Diff line change
Expand Up @@ -112,7 +112,7 @@ def system(session):
session.install("mock", "pytest")
for local_dep in LOCAL_DEPS:
session.install("-e", local_dep)
systest_deps = ["../test_utils/", "../pubsub", "../kms"]
systest_deps = ["../test_utils/", "../pubsub", "../kms", "../iam"]
for systest_dep in systest_deps:
session.install("-e", systest_dep)
session.install("-e", ".")
Expand Down
35 changes: 32 additions & 3 deletions storage/tests/system.py
Original file line number Diff line number Diff line change
Expand Up @@ -27,13 +27,13 @@
import six

from google.cloud import exceptions
from google.cloud import iam_credentials_v1
from google.cloud import storage
from google.cloud.storage._helpers import _base64_md5hash
from google.cloud.storage.bucket import LifecycleRuleDelete
from google.cloud.storage.bucket import LifecycleRuleSetStorageClass
from google.cloud import kms
import google.oauth2

from test_utils.retry import RetryErrors
from test_utils.system import unique_resource_id
from test_utils.vpcsc_config import vpcsc_config
Expand Down Expand Up @@ -109,7 +109,6 @@ def tearDown(self):

def test_get_service_account_email(self):
domain = "gs-project-accounts.iam.gserviceaccount.com"

email = Config.CLIENT.get_service_account_email()

new_style = re.compile(r"service-(?P<projnum>[^@]+)@" + domain)
Expand Down Expand Up @@ -962,6 +961,8 @@ def _create_signed_read_url_helper(
payload=None,
expiration=None,
encryption_key=None,
service_account_email=None,
access_token=None,
):
expiration = self._morph_expiration(version, expiration)

Expand All @@ -972,7 +973,12 @@ def _create_signed_read_url_helper(
blob = self.blob

signed_url = blob.generate_signed_url(
expiration=expiration, method=method, client=Config.CLIENT, version=version
expiration=expiration,
method=method,
client=Config.CLIENT,
version=version,
service_account_email=None,
access_token=None,
)

headers = {}
Expand Down Expand Up @@ -1045,6 +1051,29 @@ def test_create_signed_read_url_v4_w_csek(self):
version="v4",
)

def test_create_signed_read_url_v2_w_access_token(self):
client = iam_credentials_v1.IAMCredentialsClient()
service_account_email = Config.CLIENT._credentials.service_account_email
name = client.service_account_path("-", service_account_email)
scope = ["https://www.googleapis.com/auth/devstorage.read_write"]
response = client.generate_access_token(name, scope)
self._create_signed_read_url_helper(
service_account_email=service_account_email,
access_token=response.access_token,
)

def test_create_signed_read_url_v4_w_access_token(self):
client = iam_credentials_v1.IAMCredentialsClient()
service_account_email = Config.CLIENT._credentials.service_account_email
name = client.service_account_path("-", service_account_email)
scope = ["https://www.googleapis.com/auth/devstorage.read_write"]
response = client.generate_access_token(name, scope)
self._create_signed_read_url_helper(
version="v4",
service_account_email=service_account_email,
access_token=response.access_token,
)

def _create_signed_delete_url_helper(self, version="v2", expiration=None):
expiration = self._morph_expiration(version, expiration)

Expand Down
76 changes: 76 additions & 0 deletions storage/tests/unit/test__signing.py
Original file line number Diff line number Diff line change
Expand Up @@ -390,6 +390,8 @@ def _generate_helper(
generation=generation,
headers=headers,
query_parameters=query_parameters,
service_account_email=None,
access_token=None,
)

# Check the mock was called.
Expand Down Expand Up @@ -504,6 +506,22 @@ def test_with_google_credentials(self):
with self.assertRaises(AttributeError):
self._call_fut(credentials, resource=resource, expiration=expiration)

def test_with_access_token(self):
resource = "/name/path"
credentials = _make_credentials()
expiration = int(time.time() + 5)
email = mock.sentinel.service_account_email
with mock.patch(
"google.cloud.storage._signing._sign_message", return_value=b"DEADBEEF"
):
self._call_fut(
credentials,
resource=resource,
expiration=expiration,
service_account_email=email,
access_token="token",
)


class Test_generate_signed_url_v4(unittest.TestCase):
DEFAULT_EXPIRATION = 1000
Expand Down Expand Up @@ -638,6 +656,51 @@ def test_w_custom_query_parameters_w_string_value(self):
def test_w_custom_query_parameters_w_none_value(self):
self._generate_helper(query_parameters={"qux": None})

def test_with_access_token(self):
resource = "/name/path"
signer_email = "service@example.com"
credentials = _make_credentials(signer_email=signer_email)
with mock.patch(
"google.cloud.storage._signing._sign_message", return_value=b"DEADBEEF"
):
self._call_fut(
credentials,
resource=resource,
expiration=datetime.timedelta(days=5),
service_account_email=signer_email,
access_token="token",
)


class Test_sign_message(unittest.TestCase):
@staticmethod
def _call_fut(*args, **kwargs):
from google.cloud.storage._signing import _sign_message

return _sign_message(*args, **kwargs)

def test_sign_bytes(self):
signature = "DEADBEEF"
data = {"signature": signature}
request = make_request(200, data)
with mock.patch("google.auth.transport.requests.Request", return_value=request):
returned_signature = self._call_fut(
"123", service_account_email="service@example.com", access_token="token"
)
assert returned_signature == signature

def test_sign_bytes_failure(self):
from google.auth import exceptions

request = make_request(401)
with mock.patch("google.auth.transport.requests.Request", return_value=request):
with pytest.raises(exceptions.TransportError):
self._call_fut(
"123",
service_account_email="service@example.com",
access_token="token",
)


_DUMMY_SERVICE_ACCOUNT = None

Expand Down Expand Up @@ -697,3 +760,16 @@ def _make_credentials(signer_email=None):
return credentials
else:
return mock.Mock(spec=google.auth.credentials.Credentials)


def make_request(status, data=None):
from google.auth import transport

response = mock.create_autospec(transport.Response, instance=True)
response.status = status
if data is not None:
response.data = json.dumps(data).encode("utf-8")

request = mock.create_autospec(transport.Request)
request.return_value = response
return request
6 changes: 6 additions & 0 deletions storage/tests/unit/test_blob.py
Original file line number Diff line number Diff line change
Expand Up @@ -391,6 +391,8 @@ def _generate_signed_url_helper(
credentials=None,
expiration=None,
encryption_key=None,
access_token=None,
service_account_email=None,
):
from six.moves.urllib import parse
from google.cloud._helpers import UTC
Expand Down Expand Up @@ -432,6 +434,8 @@ def _generate_signed_url_helper(
headers=headers,
query_parameters=query_parameters,
version=version,
access_token=access_token,
service_account_email=service_account_email,
)

self.assertEqual(signed_uri, signer.return_value)
Expand Down Expand Up @@ -464,6 +468,8 @@ def _generate_signed_url_helper(
"generation": generation,
"headers": expected_headers,
"query_parameters": query_parameters,
"access_token": access_token,
"service_account_email": service_account_email,
}
signer.assert_called_once_with(expected_creds, **expected_kwargs)

Expand Down

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