openstack/swift
Code Issues Proposed changes
swift/swift/common/middleware/s3api/acl_handlers.py
Kota Tsuyuzaki 636b922f3b Import swift3 into swift repo as s3api middleware 
This attempts to import openstack/swift3 package into swift upstream
repository, namespace. This is almost simple porting except following items.

1. Rename swift3 namespace to swift.common.middleware.s3api
1.1 Rename also some conflicted class names (e.g. Request/Response)

2. Port unittests to test/unit/s3api dir to be able to run on the gate.

3. Port functests to test/functional/s3api and setup in-process testing

4. Port docs to doc dir, then address the namespace change.

5. Use get_logger() instead of global logger instance

6. Avoid global conf instance

Ex. fix various minor issue on those steps (e.g. packages, dependencies,
  deprecated things)

The details and patch references in the work on feature/s3api are listed
at https://trello.com/b/ZloaZ23t/s3api (completed board)

Note that, because this is just a porting, no new feature is developed since
the last swift3 release, and in the future work, Swift upstream may continue
to work on remaining items for further improvements and the best compatibility
of Amazon S3. Please read the new docs for your deployment and keep track to
know what would be changed in the future releases.

Change-Id: Ib803ea89cfee9a53c429606149159dd136c036fd
Co-Authored-By: Thiago da Silva <thiago@redhat.com>
Co-Authored-By: Tim Burke <tim.burke@gmail.com>
2018-04-27 15:53:57 +09:00

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# Copyright (c) 2014 OpenStack Foundation.
#
# 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.
"""
------------
Acl Handlers
------------
Why do we need this
^^^^^^^^^^^^^^^^^^^
To make controller classes clean, we need these handlers.
It is really useful for customizing acl checking algorithms for
each controller.
Basic Information
^^^^^^^^^^^^^^^^^
BaseAclHandler wraps basic Acl handling.
(i.e. it will check acl from ACL_MAP by using HEAD)
How to extend
^^^^^^^^^^^^^
Make a handler with the name of the controller.
(e.g. BucketAclHandler is for BucketController)
It consists of method(s) for actual S3 method on controllers as follows.
Example::
class BucketAclHandler(BaseAclHandler):
def PUT:
<< put acl handling algorithms here for PUT bucket >>
.. note::
If the method DON'T need to recall _get_response in outside of
acl checking, the method have to return the response it needs at
the end of method.
"""
import sys
from swift.common.middleware.s3api.subresource import ACL, Owner, encode_acl
from swift.common.middleware.s3api.s3response import MissingSecurityHeader, \
MalformedACLError, UnexpectedContent
from swift.common.middleware.s3api.etree import fromstring, XMLSyntaxError, \
DocumentInvalid
from swift.common.middleware.s3api.utils import MULTIUPLOAD_SUFFIX, \
sysmeta_header
from contextlib import contextmanager
def get_acl_handler(controller_name):
for base_klass in [BaseAclHandler, MultiUploadAclHandler]:
# pylint: disable-msg=E1101
for handler in base_klass.__subclasses__():
handler_suffix_len = len('AclHandler') \
if not handler.__name__ == 'S3AclHandler' else len('Handler')
if handler.__name__[:-handler_suffix_len] == controller_name:
return handler
return BaseAclHandler
class BaseAclHandler(object):
"""
BaseAclHandler: Handling ACL for basic requests mapped on ACL_MAP
"""
def __init__(self, req, logger):
self.req = req
self.container = self.req.container_name
self.obj = self.req.object_name
self.method = req.environ['REQUEST_METHOD']
self.user_id = self.req.user_id
self.headers = self.req.headers
self.logger = logger
@contextmanager
def request_with(self, container=None, obj=None, headers=None):
try:
org_cont = self.container
org_obj = self.obj
org_headers = self.headers
self.container = container or org_cont
self.obj = obj or org_obj
self.headers = headers or org_headers
yield
finally:
self.container = org_cont
self.obj = org_obj
self.headers = org_headers
def handle_acl(self, app, method, container=None, obj=None, headers=None):
method = method or self.method
with self.request_with(container, obj, headers):
if hasattr(self, method):
return getattr(self, method)(app)
else:
return self._handle_acl(app, method)
def _handle_acl(self, app, sw_method, container=None, obj=None,
permission=None, headers=None):
"""
General acl handling method.
This method expects to call Request._get_response() in outside of
this method so that this method returns response only when sw_method
is HEAD.
"""
container = self.container if container is None else container
obj = self.obj if obj is None else obj
sw_method = sw_method or self.req.environ['REQUEST_METHOD']
resource = 'object' if obj else 'container'
headers = self.headers if headers is None else headers
self.logger.debug(
'checking permission: %s %s %s %s' %
(container, obj, sw_method, dict(headers)))
if not container:
return
if not permission and (self.method, sw_method, resource) in ACL_MAP:
acl_check = ACL_MAP[(self.method, sw_method, resource)]
resource = acl_check.get('Resource') or resource
permission = acl_check['Permission']
if not permission:
self.logger.debug(
'%s %s %s %s' % (container, obj, sw_method, headers))
raise Exception('No permission to be checked exists')
if resource == 'object':
resp = self.req.get_acl_response(app, 'HEAD',
container, obj,
headers)
acl = resp.object_acl
elif resource == 'container':
resp = self.req.get_acl_response(app, 'HEAD',
container, '')
acl = resp.bucket_acl
try:
acl.check_permission(self.user_id, permission)
except Exception as e:
self.logger.debug(acl)
self.logger.debug('permission denined: %s %s %s' %
(e, self.user_id, permission))
raise
if sw_method == 'HEAD':
return resp
def get_acl(self, headers, body, bucket_owner, object_owner=None):
"""
Get ACL instance from S3 (e.g. x-amz-grant) headers or S3 acl xml body.
"""
acl = ACL.from_headers(headers, bucket_owner, object_owner,
as_private=False)
if acl is None:
# Get acl from request body if possible.
if not body:
raise MissingSecurityHeader(missing_header_name='x-amz-acl')
try:
elem = fromstring(body, ACL.root_tag)
acl = ACL.from_elem(
elem, True, self.req.allow_no_owner)
except(XMLSyntaxError, DocumentInvalid):
raise MalformedACLError()
except Exception as e:
exc_type, exc_value, exc_traceback = sys.exc_info()
self.logger.error(e)
raise exc_type, exc_value, exc_traceback
else:
if body:
# Specifying grant with both header and xml is not allowed.
raise UnexpectedContent()
return acl
class BucketAclHandler(BaseAclHandler):
"""
BucketAclHandler: Handler for BucketController
"""
def DELETE(self, app):
if self.container.endswith(MULTIUPLOAD_SUFFIX):
# anyways, delete multiupload container doesn't need acls
# because it depends on GET segment container result for
# cleanup
pass
else:
return self._handle_acl(app, 'DELETE')
def HEAD(self, app):
if self.method == 'DELETE':
return self._handle_acl(app, 'DELETE')
else:
return self._handle_acl(app, 'HEAD')
def GET(self, app):
if self.method == 'DELETE' and \
self.container.endswith(MULTIUPLOAD_SUFFIX):
pass
else:
return self._handle_acl(app, 'GET')
def PUT(self, app):
req_acl = ACL.from_headers(self.req.headers,
Owner(self.user_id, self.user_id))
# To avoid overwriting the existing bucket's ACL, we send PUT
# request first before setting the ACL to make sure that the target
# container does not exist.
self.req.get_acl_response(app, 'PUT')
# update metadata
self.req.bucket_acl = req_acl
# FIXME If this request is failed, there is a possibility that the
# bucket which has no ACL is left.
return self.req.get_acl_response(app, 'POST')
class ObjectAclHandler(BaseAclHandler):
"""
ObjectAclHandler: Handler for ObjectController
"""
def HEAD(self, app):
# No check object permission needed at DELETE Object
if self.method != 'DELETE':
return self._handle_acl(app, 'HEAD')
def PUT(self, app):
b_resp = self._handle_acl(app, 'HEAD', obj='')
req_acl = ACL.from_headers(self.req.headers,
b_resp.bucket_acl.owner,
Owner(self.user_id, self.user_id))
self.req.object_acl = req_acl
class S3AclHandler(BaseAclHandler):
"""
S3AclHandler: Handler for S3AclController
"""
def GET(self, app):
self._handle_acl(app, 'HEAD', permission='READ_ACP')
def PUT(self, app):
if self.req.is_object_request:
b_resp = self.req.get_acl_response(app, 'HEAD', obj='')
o_resp = self._handle_acl(app, 'HEAD', permission='WRITE_ACP')
req_acl = self.get_acl(self.req.headers,
self.req.xml(ACL.max_xml_length),
b_resp.bucket_acl.owner,
o_resp.object_acl.owner)
# Don't change the owner of the resource by PUT acl request.
o_resp.object_acl.check_owner(req_acl.owner.id)
for g in req_acl.grants:
self.logger.debug(
'Grant %s %s permission on the object /%s/%s' %
(g.grantee, g.permission, self.req.container_name,
self.req.object_name))
self.req.object_acl = req_acl
else:
self._handle_acl(app, self.method)
def POST(self, app):
if self.req.is_bucket_request:
resp = self._handle_acl(app, 'HEAD', permission='WRITE_ACP')
req_acl = self.get_acl(self.req.headers,
self.req.xml(ACL.max_xml_length),
resp.bucket_acl.owner)
# Don't change the owner of the resource by PUT acl request.
resp.bucket_acl.check_owner(req_acl.owner.id)
for g in req_acl.grants:
self.logger.debug(
'Grant %s %s permission on the bucket /%s' %
(g.grantee, g.permission, self.req.container_name))
self.req.bucket_acl = req_acl
else:
self._handle_acl(app, self.method)
class MultiObjectDeleteAclHandler(BaseAclHandler):
"""
MultiObjectDeleteAclHandler: Handler for MultiObjectDeleteController
"""
def HEAD(self, app):
# Only bucket write acl is required
if not self.obj:
return self._handle_acl(app, 'HEAD')
def DELETE(self, app):
# Only bucket write acl is required
pass
class MultiUploadAclHandler(BaseAclHandler):
"""
MultiUpload stuff requires acl checking just once for BASE container
so that MultiUploadAclHandler extends BaseAclHandler to check acl only
when the verb defined. We should define the verb as the first step to
request to backend Swift at incoming request.
Basic Rules:
- BASE container name is always w/o 'MULTIUPLOAD_SUFFIX'
- Any check timing is ok but we should check it as soon as possible.
========== ====== ============= ==========
Controller Verb CheckResource Permission
========== ====== ============= ==========
Part PUT Container WRITE
Uploads GET Container READ
Uploads POST Container WRITE
Upload GET Container READ
Upload DELETE Container WRITE
Upload POST Container WRITE
========== ====== ============= ==========
"""
def __init__(self, req, logger):
super(MultiUploadAclHandler, self).__init__(req, logger)
self.acl_checked = False
def handle_acl(self, app, method, container=None, obj=None, headers=None):
method = method or self.method
with self.request_with(container, obj, headers):
# MultiUpload stuffs don't need acl check basically.
if hasattr(self, method):
return getattr(self, method)(app)
else:
pass
def HEAD(self, app):
# For _check_upload_info
self._handle_acl(app, 'HEAD', self.container, '')
class PartAclHandler(MultiUploadAclHandler):
"""
PartAclHandler: Handler for PartController
"""
def __init__(self, req, logger):
# pylint: disable-msg=E1003
super(MultiUploadAclHandler, self).__init__(req, logger)
def HEAD(self, app):
if self.container.endswith(MULTIUPLOAD_SUFFIX):
# For _check_upload_info
container = self.container[:-len(MULTIUPLOAD_SUFFIX)]
self._handle_acl(app, 'HEAD', container, '')
else:
# For check_copy_source
return self._handle_acl(app, 'HEAD', self.container, self.obj)
class UploadsAclHandler(MultiUploadAclHandler):
"""
UploadsAclHandler: Handler for UploadsController
"""
def handle_acl(self, app, method, *args, **kwargs):
method = method or self.method
if hasattr(self, method):
return getattr(self, method)(app)
else:
pass
def GET(self, app):
# List Multipart Upload
self._handle_acl(app, 'GET', self.container, '')
def PUT(self, app):
if not self.acl_checked:
resp = self._handle_acl(app, 'HEAD', obj='')
req_acl = ACL.from_headers(self.req.headers,
resp.bucket_acl.owner,
Owner(self.user_id, self.user_id))
acl_headers = encode_acl('object', req_acl)
self.req.headers[sysmeta_header('object', 'tmpacl')] = \
acl_headers[sysmeta_header('object', 'acl')]
self.acl_checked = True
class UploadAclHandler(MultiUploadAclHandler):
"""
UploadAclHandler: Handler for UploadController
"""
def handle_acl(self, app, method, *args, **kwargs):
method = method or self.method
if hasattr(self, method):
return getattr(self, method)(app)
else:
pass
def HEAD(self, app):
# FIXME: GET HEAD case conflicts with GET service
method = 'GET' if self.method == 'GET' else 'HEAD'
self._handle_acl(app, method, self.container, '')
def PUT(self, app):
container = self.req.container_name + MULTIUPLOAD_SUFFIX
obj = '%s/%s' % (self.obj, self.req.params['uploadId'])
resp = self.req._get_response(app, 'HEAD', container, obj)
self.req.headers[sysmeta_header('object', 'acl')] = \
resp.sysmeta_headers.get(sysmeta_header('object', 'tmpacl'))
"""
ACL_MAP =
{
('<s3_method>', '<swift_method>', '<swift_resource>'):
{'Resource': '<check_resource>',
'Permission': '<check_permission>'},
...
}
s3_method: Method of S3 Request from user to s3api
swift_method: Method of Swift Request from s3api to swift
swift_resource: Resource of Swift Request from s3api to swift
check_resource: <container/object>
check_permission: <OWNER/READ/WRITE/READ_ACP/WRITE_ACP>
"""
ACL_MAP = {
# HEAD Bucket
('HEAD', 'HEAD', 'container'):
{'Permission': 'READ'},
# GET Service
('GET', 'HEAD', 'container'):
{'Permission': 'OWNER'},
# GET Bucket, List Parts, List Multipart Upload
('GET', 'GET', 'container'):
{'Permission': 'READ'},
# PUT Object, PUT Object Copy
('PUT', 'HEAD', 'container'):
{'Permission': 'WRITE'},
# DELETE Bucket
('DELETE', 'DELETE', 'container'):
{'Permission': 'OWNER'},
# HEAD Object
('HEAD', 'HEAD', 'object'):
{'Permission': 'READ'},
# GET Object
('GET', 'GET', 'object'):
{'Permission': 'READ'},
# PUT Object Copy, Upload Part Copy
('PUT', 'HEAD', 'object'):
{'Permission': 'READ'},
# Abort Multipart Upload
('DELETE', 'HEAD', 'container'):
{'Permission': 'WRITE'},
# Delete Object
('DELETE', 'DELETE', 'object'):
{'Resource': 'container',
'Permission': 'WRITE'},
# Complete Multipart Upload, DELETE Multiple Objects,
# Initiate Multipart Upload
('POST', 'HEAD', 'container'):
{'Permission': 'WRITE'},
}
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