mirror of https://github.com/ceph/ceph
215 lines
8.4 KiB
ReStructuredText
215 lines
8.4 KiB
ReStructuredText
=========
|
||
STS Lite
|
||
=========
|
||
|
||
Ceph Object Gateway provides support for a subset of Amazon Secure Token Service
|
||
(STS) APIs. STS Lite provides access to a set of temporary credentials for
|
||
Identity and Access Management.
|
||
|
||
STS authentication mechanism has been integrated with Keystone in Ceph Object
|
||
Gateway. A set of temporary security credentials is returned after authenticating
|
||
a set of AWS credentials with Keystone. These temporary credentials can be used
|
||
to make subsequent S3 calls which will be authenticated by the STS engine,
|
||
resulting in less load on the Keystone server.
|
||
|
||
STS Lite REST APIs
|
||
==================
|
||
|
||
The following STS Lite REST APIs have been implemented in Ceph Object Gateway:
|
||
|
||
1. GetSessionToken: Returns a set of temporary credentials for a set of AWS
|
||
credentials. This API can be used for initial authentication with Keystone
|
||
and the temporary credentials returned can be used to make subsequent S3
|
||
calls. The temporary credentials will have the same permission as that of the
|
||
AWS credentials.
|
||
|
||
Parameters:
|
||
**DurationSeconds** (Integer/ Optional): The duration in seconds for which the
|
||
credentials should remain valid. Its default value is 3600. Its default max
|
||
value is 43200 which is can be configured using rgw sts max session duration.
|
||
|
||
**SerialNumber** (String/ Optional): The Id number of the MFA device associated
|
||
with the user making the GetSessionToken call.
|
||
|
||
**TokenCode** (String/ Optional): The value provided by the MFA device, if the
|
||
trust policy of the role being assumed requires MFA.
|
||
|
||
|
||
2. AssumeRole: Returns a set of temporary credentials that can be used for
|
||
cross-account access. The temporary credentials will have permissions that are
|
||
allowed by both - permission policies attached with the Role and policy attached
|
||
with the AssumeRole API.
|
||
|
||
Parameters:
|
||
**RoleArn** (String/ Required): ARN of the Role to Assume.
|
||
|
||
**RoleSessionName** (String/ Required): An Identifier for the assumed role
|
||
session.
|
||
|
||
**Policy** (String/ Optional): An IAM Policy in JSON format.
|
||
|
||
**DurationSeconds** (Integer/ Optional): The duration in seconds of the session.
|
||
Its default value is 3600.
|
||
|
||
**ExternalId** (String/ Optional): A unique Id that might be used when a role is
|
||
assumed in another account.
|
||
|
||
**SerialNumber** (String/ Optional): The Id number of the MFA device associated
|
||
with the user making the AssumeRole call.
|
||
|
||
**TokenCode** (String/ Optional): The value provided by the MFA device, if the
|
||
trust policy of the role being assumed requires MFA.
|
||
|
||
|
||
STS Lite Configuration
|
||
======================
|
||
|
||
The following configurable options are available for STS Lite integration::
|
||
|
||
[client.radosgw.gateway]
|
||
rgw sts key = {sts key for encrypting the session token}
|
||
rgw s3 auth use sts = true
|
||
|
||
The above STS configurables can be used with the Keystone configurables if one
|
||
needs to use STS Lite in conjunction with Keystone. The complete set of
|
||
configurable options will be::
|
||
|
||
[client.radosgw.gateway]
|
||
rgw sts key = {sts key for encrypting/ decrypting the session token}
|
||
rgw s3 auth use sts = true
|
||
|
||
rgw keystone url = {keystone server url:keystone server admin port}
|
||
rgw keystone admin project = {keystone admin project name}
|
||
rgw keystone admin tenant = {keystone service tenant name}
|
||
rgw keystone admin domain = {keystone admin domain name}
|
||
rgw keystone api version = {keystone api version}
|
||
rgw keystone implicit tenants = {true for private tenant for each new user}
|
||
rgw keystone admin password = {keystone service tenant user name}
|
||
rgw keystone admin user = keystone service tenant user password}
|
||
rgw keystone accepted roles = {accepted user roles}
|
||
rgw keystone token cache size = {number of tokens to cache}
|
||
rgw keystone revocation interval = {number of seconds before checking revoked tickets}
|
||
rgw s3 auth use keystone = true
|
||
rgw nss db path = {path to nss db}
|
||
|
||
Note: By default, STS and S3 APIs co-exist in the same namespace, and both S3
|
||
and STS APIs can be accessed via the same endpoint in Ceph Object Gateway.
|
||
|
||
Example showing how to Use STS Lite with Keystone
|
||
=================================================
|
||
|
||
The following are the steps needed to use STS Lite with Keystone. Boto 3.x has
|
||
been used to write an example code to show the integration of STS Lite with
|
||
Keystone.
|
||
|
||
1. Generate EC2 credentials :
|
||
|
||
.. code-block:: javascript
|
||
|
||
openstack ec2 credentials create
|
||
+------------+--------------------------------------------------------+
|
||
| Field | Value |
|
||
+------------+--------------------------------------------------------+
|
||
| access | b924dfc87d454d15896691182fdeb0ef |
|
||
| links | {u'self': u'http://192.168.0.15/identity/v3/users/ |
|
||
| | 40a7140e424f493d8165abc652dc731c/credentials/ |
|
||
| | OS-EC2/b924dfc87d454d15896691182fdeb0ef'} |
|
||
| project_id | c703801dccaf4a0aaa39bec8c481e25a |
|
||
| secret | 6a2142613c504c42a94ba2b82147dc28 |
|
||
| trust_id | None |
|
||
| user_id | 40a7140e424f493d8165abc652dc731c |
|
||
+------------+--------------------------------------------------------+
|
||
|
||
2. Use the credentials created in the step 1. to get back a set of temporary
|
||
credentials using GetSessionToken API.
|
||
|
||
.. code-block:: python
|
||
|
||
import boto3
|
||
|
||
access_key = <ec2 access key>
|
||
secret_key = <ec2 secret key>
|
||
|
||
client = boto3.client('sts',
|
||
aws_access_key_id=access_key,
|
||
aws_secret_access_key=secret_key,
|
||
endpoint_url=<STS URL>,
|
||
region_name='',
|
||
)
|
||
|
||
response = client.get_session_token(
|
||
DurationSeconds=43200
|
||
)
|
||
|
||
3. The temporary credentials obtained in step 2. can be used for making S3 calls:
|
||
|
||
.. code-block:: python
|
||
|
||
s3client = boto3.client('s3',
|
||
aws_access_key_id = response['Credentials']['AccessKeyId'],
|
||
aws_secret_access_key = response['Credentials']['SecretAccessKey'],
|
||
aws_session_token = response['Credentials']['SessionToken'],
|
||
endpoint_url=<S3 URL>,
|
||
region_name='')
|
||
|
||
bucket = s3client.create_bucket(Bucket='my-new-shiny-bucket')
|
||
response = s3client.list_buckets()
|
||
for bucket in response["Buckets"]:
|
||
print "{name}\t{created}".format(
|
||
name = bucket['Name'],
|
||
created = bucket['CreationDate'],
|
||
)
|
||
|
||
Limitations and Workarounds
|
||
===========================
|
||
|
||
1. Keystone currently supports only S3 requests, hence in order to successfully
|
||
authenticate an STS request, the following workaround needs to be added to boto
|
||
to the following file - botocore/auth.py
|
||
|
||
Lines 13-16 have been added as a workaround in the code block below:
|
||
|
||
.. code-block:: python
|
||
|
||
class SigV4Auth(BaseSigner):
|
||
"""
|
||
Sign a request with Signature V4.
|
||
"""
|
||
REQUIRES_REGION = True
|
||
|
||
def __init__(self, credentials, service_name, region_name):
|
||
self.credentials = credentials
|
||
# We initialize these value here so the unit tests can have
|
||
# valid values. But these will get overriden in ``add_auth``
|
||
# later for real requests.
|
||
self._region_name = region_name
|
||
if service_name == 'sts':
|
||
self._service_name = 's3'
|
||
else:
|
||
self._service_name = service_name
|
||
|
||
2. Currently boto does not include the payload hash with the request, but uses
|
||
it to calculate the signature for STS requests, which results in an incorrect
|
||
signature at the server side. The workaround is to send the payload hash in the
|
||
request itself. The changes are in the file – botocore/auth.py.
|
||
|
||
Lines 14-15 have been added as a workaround in the code block below:
|
||
|
||
.. code-block:: python
|
||
|
||
def _modify_request_before_signing(self, request):
|
||
if 'Authorization' in request.headers:
|
||
del request.headers['Authorization']
|
||
self._set_necessary_date_headers(request)
|
||
if self.credentials.token:
|
||
if 'X-Amz-Security-Token' in request.headers:
|
||
del request.headers['X-Amz-Security-Token']
|
||
request.headers['X-Amz-Security-Token'] = self.credentials.token
|
||
|
||
if not request.context.get('payload_signing_enabled', True):
|
||
if 'X-Amz-Content-SHA256' in request.headers:
|
||
del request.headers['X-Amz-Content-SHA256']
|
||
request.headers['X-Amz-Content-SHA256'] = UNSIGNED_PAYLOAD
|
||
else:
|
||
request.headers['X-Amz-Content-SHA256'] = self.payload(request)
|