212 lines
7.4 KiB
Python
212 lines
7.4 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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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, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Metadata request handler."""
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import hashlib
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import hmac
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import os
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from oslo.config import cfg
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import webob.dec
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import webob.exc
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from nova.api.metadata import base
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from nova import conductor
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from nova import exception
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from nova.openstack.common.gettextutils import _
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from nova.openstack.common import log as logging
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from nova.openstack.common import memorycache
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from nova import wsgi
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CACHE_EXPIRATION = 15 # in seconds
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CONF = cfg.CONF
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CONF.import_opt('use_forwarded_for', 'nova.api.auth')
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metadata_proxy_opts = [
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cfg.BoolOpt(
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'service_neutron_metadata_proxy',
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default=False,
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deprecated_name='service_quantum_metadata_proxy',
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help='Set flag to indicate Neutron will proxy metadata requests and '
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'resolve instance ids.'),
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cfg.StrOpt(
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'neutron_metadata_proxy_shared_secret',
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default='',
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deprecated_name='quantum_metadata_proxy_shared_secret',
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help='Shared secret to validate proxies Neutron metadata requests')
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]
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CONF.register_opts(metadata_proxy_opts)
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LOG = logging.getLogger(__name__)
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class MetadataRequestHandler(wsgi.Application):
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"""Serve metadata."""
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def __init__(self):
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self._cache = memorycache.get_client()
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self.conductor_api = conductor.API()
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def get_metadata_by_remote_address(self, address):
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if not address:
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raise exception.FixedIpNotFoundForAddress(address=address)
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cache_key = 'metadata-%s' % address
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data = self._cache.get(cache_key)
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if data:
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return data
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try:
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data = base.get_metadata_by_address(self.conductor_api, address)
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except exception.NotFound:
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return None
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self._cache.set(cache_key, data, CACHE_EXPIRATION)
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return data
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def get_metadata_by_instance_id(self, instance_id, address):
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cache_key = 'metadata-%s' % instance_id
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data = self._cache.get(cache_key)
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if data:
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return data
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try:
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data = base.get_metadata_by_instance_id(self.conductor_api,
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instance_id, address)
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except exception.NotFound:
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return None
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self._cache.set(cache_key, data, CACHE_EXPIRATION)
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return data
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@webob.dec.wsgify(RequestClass=wsgi.Request)
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def __call__(self, req):
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if os.path.normpath(req.path_info) == "/":
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return(base.ec2_md_print(base.VERSIONS + ["latest"]))
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if CONF.service_neutron_metadata_proxy:
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meta_data = self._handle_instance_id_request(req)
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else:
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if req.headers.get('X-Instance-ID'):
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LOG.warn(
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_("X-Instance-ID present in request headers. The "
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"'service_neutron_metadata_proxy' option must be enabled"
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" to process this header."))
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meta_data = self._handle_remote_ip_request(req)
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if meta_data is None:
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raise webob.exc.HTTPNotFound()
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try:
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data = meta_data.lookup(req.path_info)
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except base.InvalidMetadataPath:
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raise webob.exc.HTTPNotFound()
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if callable(data):
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return data(req, meta_data)
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return base.ec2_md_print(data)
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def _handle_remote_ip_request(self, req):
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remote_address = req.remote_addr
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if CONF.use_forwarded_for:
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remote_address = req.headers.get('X-Forwarded-For', remote_address)
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try:
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meta_data = self.get_metadata_by_remote_address(remote_address)
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except Exception:
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LOG.exception(_('Failed to get metadata for ip: %s'),
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remote_address)
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msg = _('An unknown error has occurred. '
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'Please try your request again.')
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raise webob.exc.HTTPInternalServerError(explanation=unicode(msg))
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if meta_data is None:
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LOG.error(_('Failed to get metadata for ip: %s'), remote_address)
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return meta_data
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def _handle_instance_id_request(self, req):
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instance_id = req.headers.get('X-Instance-ID')
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tenant_id = req.headers.get('X-Tenant-ID')
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signature = req.headers.get('X-Instance-ID-Signature')
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remote_address = req.headers.get('X-Forwarded-For')
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# Ensure that only one header was passed
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if instance_id is None:
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msg = _('X-Instance-ID header is missing from request.')
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elif tenant_id is None:
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msg = _('X-Tenant-ID header is missing from request.')
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elif not isinstance(instance_id, basestring):
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msg = _('Multiple X-Instance-ID headers found within request.')
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elif not isinstance(tenant_id, basestring):
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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.neutron_metadata_proxy_shared_secret,
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instance_id,
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hashlib.sha256).hexdigest()
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if expected_signature != signature:
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if instance_id:
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LOG.warn(_('X-Instance-ID-Signature: %(signature)s does not '
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'match the expected value: %(expected_signature)s '
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'for id: %(instance_id)s. Request From: '
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'%(remote_address)s'),
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{'signature': signature,
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'expected_signature': expected_signature,
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'instance_id': instance_id,
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'remote_address': remote_address})
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msg = _('Invalid proxy request signature.')
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raise webob.exc.HTTPForbidden(explanation=msg)
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try:
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meta_data = self.get_metadata_by_instance_id(instance_id,
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remote_address)
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except Exception:
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LOG.exception(_('Failed to get metadata for instance id: %s'),
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instance_id)
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msg = _('An unknown error has occurred. '
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'Please try your request again.')
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raise webob.exc.HTTPInternalServerError(explanation=unicode(msg))
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if meta_data is None:
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LOG.error(_('Failed to get metadata for instance id: %s'),
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instance_id)
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if meta_data.instance['project_id'] != tenant_id:
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LOG.warning(_("Tenant_id %(tenant_id)s does not match tenant_id "
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"of instance %(instance_id)s."),
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{'tenant_id': tenant_id,
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'instance_id': instance_id})
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# causes a 404 to be raised
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meta_data = None
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return meta_data
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