249 lines
9.4 KiB
Python
249 lines
9.4 KiB
Python
# Copyright 2014
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# The Cloudscaling Group, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import hashlib
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import hmac
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import posixpath
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import urlparse
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import httplib2
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from oslo_config import cfg
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from oslo_log import log as logging
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import six
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import webob
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from ec2api import context as ec2context
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from ec2api import exception
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from ec2api.i18n import _, _LE, _LW
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from ec2api.metadata import api
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from ec2api import utils
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from ec2api import wsgi
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LOG = logging.getLogger(__name__)
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CONF = cfg.CONF
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CONF.import_opt('use_forwarded_for', 'ec2api.api.auth')
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metadata_opts = [
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cfg.StrOpt('nova_metadata_ip',
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default='127.0.0.1',
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help=_("IP address used by Nova metadata server.")),
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cfg.IntOpt('nova_metadata_port',
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default=8775,
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help=_("TCP Port used by Nova metadata server.")),
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cfg.StrOpt('nova_metadata_protocol',
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default='http',
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choices=['http', 'https'],
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help=_("Protocol to access nova metadata, http or https")),
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cfg.BoolOpt('nova_metadata_insecure',
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default=False,
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help=_("Allow to perform insecure SSL (https) requests to "
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"nova metadata")),
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cfg.StrOpt('auth_ca_cert',
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help=_("Certificate Authority public key (CA cert) "
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"file for ssl")),
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cfg.StrOpt('nova_client_cert',
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default='',
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help=_("Client certificate for nova metadata api server.")),
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cfg.StrOpt('nova_client_priv_key',
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default='',
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help=_("Private key of client certificate.")),
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cfg.StrOpt('metadata_proxy_shared_secret',
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default='',
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help=_('Shared secret to sign instance-id request'),
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secret=True),
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]
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CONF.register_opts(metadata_opts, group='metadata')
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class MetadataRequestHandler(wsgi.Application):
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"""Serve metadata."""
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@webob.dec.wsgify(RequestClass=wsgi.Request)
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def __call__(self, req):
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LOG.debug('Request: %s', req)
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path = req.path_info
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if path == '' or path[0] != '/':
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path = '/' + path
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path = posixpath.normpath(path)
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path_tokens = path.split('/')[1:]
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if path_tokens in ([''], ['ec2']):
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resp = api.get_version_list()
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return self._add_response_data(req.response, resp)
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try:
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if path_tokens[0] == 'openstack':
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return self._proxy_request(req)
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elif path_tokens[0] == 'ec2':
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path_tokens = path_tokens[1:]
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resp = self._get_metadata(req, path_tokens)
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return self._add_response_data(req.response, resp)
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except exception.EC2MetadataNotFound:
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return webob.exc.HTTPNotFound()
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except Exception:
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LOG.exception(_LE("Unexpected error."))
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msg = _('An unknown error has occurred. '
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'Please try your request again.')
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return webob.exc.HTTPInternalServerError(explanation=unicode(msg))
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def _proxy_request(self, req):
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headers = self._build_proxy_request_headers(req)
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nova_ip_port = '%s:%s' % (CONF.metadata.nova_metadata_ip,
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CONF.metadata.nova_metadata_port)
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url = urlparse.urlunsplit((
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CONF.metadata.nova_metadata_protocol,
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nova_ip_port,
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req.path_info,
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req.query_string,
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''))
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h = httplib2.Http(
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ca_certs=CONF.metadata.auth_ca_cert,
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disable_ssl_certificate_validation=(
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CONF.metadata.nova_metadata_insecure)
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)
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if (CONF.metadata.nova_client_cert and
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CONF.metadata.nova_client_priv_key):
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h.add_certificate(CONF.metadata.nova_client_priv_key,
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CONF.metadata.nova_client_cert,
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nova_ip_port)
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resp, content = h.request(url, method=req.method, headers=headers,
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body=req.body)
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if resp.status == 200:
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LOG.debug(str(resp))
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req.response.content_type = resp['content-type']
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req.response.body = content
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return req.response
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elif resp.status == 403:
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LOG.warn(_LW(
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'The remote metadata server responded with Forbidden. This '
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'response usually occurs when shared secrets do not match.'
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))
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return webob.exc.HTTPForbidden()
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elif resp.status == 400:
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return webob.exc.HTTPBadRequest()
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elif resp.status == 404:
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return webob.exc.HTTPNotFound()
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elif resp.status == 409:
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return webob.exc.HTTPConflict()
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elif resp.status == 500:
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msg = _(
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'Remote metadata server experienced an internal server error.'
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)
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LOG.warn(msg)
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return webob.exc.HTTPInternalServerError(explanation=unicode(msg))
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else:
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raise Exception(_('Unexpected response code: %s') % resp.status)
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def _build_proxy_request_headers(self, req):
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if req.headers.get('X-Instance-ID'):
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return req.headers
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remote_ip = self._get_remote_ip(req)
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context = ec2context.get_os_admin_context()
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instance_id, project_id = (
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api.get_os_instance_and_project_id(context, remote_ip))
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return {
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'X-Forwarded-For': remote_ip,
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'X-Instance-ID': instance_id,
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'X-Tenant-ID': project_id,
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'X-Instance-ID-Signature': self._sign_instance_id(instance_id),
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}
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def _get_remote_ip(self, req):
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remote_ip = req.remote_addr
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if CONF.use_forwarded_for:
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remote_ip = req.headers.get('X-Forwarded-For', remote_ip)
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if not remote_ip:
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raise exception.EC2MetadataInvalidAddress()
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return remote_ip
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def _sign_instance_id(self, instance_id):
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return hmac.new(CONF.metadata.metadata_proxy_shared_secret,
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instance_id,
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hashlib.sha256).hexdigest()
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def _get_metadata(self, req, path_tokens):
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context = ec2context.get_os_admin_context()
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if req.headers.get('X-Instance-ID'):
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os_instance_id, project_id, remote_ip = (
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self._unpack_request_attributes(req))
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else:
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remote_ip = self._get_remote_ip(req)
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os_instance_id, project_id = (
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api.get_os_instance_and_project_id(context, remote_ip))
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# NOTE(ft): substitute project_id for context to instance's one.
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# It's needed for correct describe and auto update DB operations.
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# It doesn't affect operations via OpenStack's clients because
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# these clients use auth_token field only
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context.project_id = project_id
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return api.get_metadata_item(context, path_tokens, os_instance_id,
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remote_ip)
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def _unpack_request_attributes(self, req):
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os_instance_id = req.headers.get('X-Instance-ID')
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project_id = req.headers.get('X-Tenant-ID')
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signature = req.headers.get('X-Instance-ID-Signature')
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remote_ip = req.headers.get('X-Forwarded-For')
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if not remote_ip:
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raise exception.EC2MetadataInvalidAddress()
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if os_instance_id is None:
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msg = _('X-Instance-ID header is missing from request.')
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elif project_id is None:
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msg = _('X-Tenant-ID header is missing from request.')
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elif not isinstance(os_instance_id, six.string_types):
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msg = _('Multiple X-Instance-ID headers found within request.')
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elif not isinstance(project_id, six.string_types):
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msg = _('Multiple X-Tenant-ID headers found within request.')
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else:
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msg = None
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if msg:
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raise webob.exc.HTTPBadRequest(explanation=msg)
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expected_signature = hmac.new(
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CONF.metadata.metadata_proxy_shared_secret,
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os_instance_id,
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hashlib.sha256).hexdigest()
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if not utils.constant_time_compare(expected_signature, signature):
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LOG.warning(_LW(
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'X-Instance-ID-Signature: %(signature)s does '
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'not match the expected value: '
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'%(expected_signature)s for id: '
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'%(instance_id)s. Request From: '
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'%(remote_ip)s'),
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{'signature': signature,
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'expected_signature': expected_signature,
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'instance_id': os_instance_id,
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'remote_ip': remote_ip})
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msg = _('Invalid proxy request signature.')
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raise webob.exc.HTTPForbidden(explanation=msg)
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return os_instance_id, project_id, remote_ip
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def _add_response_data(self, response, data):
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if isinstance(data, six.text_type):
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response.text = data
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else:
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response.body = data
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response.content_type = 'text/plain'
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return response
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