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Merge pull request #957 from matrix-org/markjh/verify

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Clean up verify_json_objects_for_server
This commit is contained in:
Mark Haines 2016-07-27 15:33:32 +01:00 committed by GitHub
commit c38b7c4104
1 changed files with 79 additions and 73 deletions
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142
synapse/crypto/keyring.py
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@ -44,7 +44,21 @@ import logging
logger = logging.getLogger(__name__)
KeyGroup = namedtuple("KeyGroup", ("server_name", "group_id", "key_ids"))
VerifyKeyRequest = namedtuple("VerifyRequest", (
"server_name", "key_ids", "json_object", "deferred"
))
"""
A request for a verify key to verify a JSON object.
Attributes:
server_name(str): The name of the server to verify against.
key_ids(set(str)): The set of key_ids to that could be used to verify the
JSON object
json_object(dict): The JSON object to verify.
deferred(twisted.internet.defer.Deferred):
A deferred (server_name, key_id, verify_key) tuple that resolves when
a verify key has been fetched
"""
class Keyring(object):
@ -74,39 +88,32 @@ class Keyring(object):
list of deferreds indicating success or failure to verify each
json object's signature for the given server_name.
"""
group_id_to_json = {}
group_id_to_group = {}
group_ids = []
next_group_id = 0
deferreds = {}
verify_requests = []
for server_name, json_object in server_and_json:
logger.debug("Verifying for %s", server_name)
group_id = next_group_id
next_group_id += 1
group_ids.append(group_id)
key_ids = signature_ids(json_object, server_name)
if not key_ids:
deferreds[group_id] = defer.fail(SynapseError(
deferred = defer.fail(SynapseError(
400,
"Not signed with a supported algorithm",
Codes.UNAUTHORIZED,
))
else:
deferreds[group_id] = defer.Deferred()
deferred = defer.Deferred()
group = KeyGroup(server_name, group_id, key_ids)
verify_request = VerifyKeyRequest(
server_name, key_ids, json_object, deferred
)
group_id_to_group[group_id] = group
group_id_to_json[group_id] = json_object
verify_requests.append(verify_request)
@defer.inlineCallbacks
def handle_key_deferred(group, deferred):
server_name = group.server_name
def handle_key_deferred(verify_request):
server_name = verify_request.server_name
try:
_, _, key_id, verify_key = yield deferred
_, key_id, verify_key = yield verify_request.deferred
except IOError as e:
logger.warn(
"Got IOError when downloading keys for %s: %s %s",
@ -128,7 +135,7 @@ class Keyring(object):
Codes.UNAUTHORIZED,
)
json_object = group_id_to_json[group.group_id]
json_object = verify_request.json_object
try:
verify_signed_json(json_object, server_name, verify_key)
@ -157,36 +164,34 @@ class Keyring(object):
# Actually start fetching keys.
wait_on_deferred.addBoth(
lambda _: self.get_server_verify_keys(group_id_to_group, deferreds)
lambda _: self.get_server_verify_keys(verify_requests)
)
# When we've finished fetching all the keys for a given server_name,
# resolve the deferred passed to `wait_for_previous_lookups` so that
# any lookups waiting will proceed.
server_to_gids = {}
server_to_request_ids = {}
def remove_deferreds(res, server_name, group_id):
server_to_gids[server_name].discard(group_id)
if not server_to_gids[server_name]:
def remove_deferreds(res, server_name, verify_request):
request_id = id(verify_request)
server_to_request_ids[server_name].discard(request_id)
if not server_to_request_ids[server_name]:
d = server_to_deferred.pop(server_name, None)
if d:
d.callback(None)
return res
for g_id, deferred in deferreds.items():
server_name = group_id_to_group[g_id].server_name
server_to_gids.setdefault(server_name, set()).add(g_id)
deferred.addBoth(remove_deferreds, server_name, g_id)
for verify_request in verify_requests:
server_name = verify_request.server_name
request_id = id(verify_request)
server_to_request_ids.setdefault(server_name, set()).add(request_id)
deferred.addBoth(remove_deferreds, server_name, verify_request)
# Pass those keys to handle_key_deferred so that the json object
# signatures can be verified
return [
preserve_context_over_fn(
handle_key_deferred,
group_id_to_group[g_id],
deferreds[g_id],
)
for g_id in group_ids
preserve_context_over_fn(handle_key_deferred, verify_request)
for verify_request in verify_requests
]
@defer.inlineCallbacks
@ -220,7 +225,7 @@ class Keyring(object):
d.addBoth(rm, server_name)
def get_server_verify_keys(self, group_id_to_group, group_id_to_deferred):
def get_server_verify_keys(self, verify_requests):
"""Takes a dict of KeyGroups and tries to find at least one key for
each group.
"""
@ -237,63 +242,64 @@ class Keyring(object):
merged_results = {}
missing_keys = {}
for group in group_id_to_group.values():
missing_keys.setdefault(group.server_name, set()).update(
group.key_ids
for verify_request in verify_requests:
missing_keys.setdefault(verify_request.server_name, set()).update(
verify_request.key_ids
)
for fn in key_fetch_fns:
results = yield fn(missing_keys.items())
merged_results.update(results)
# We now need to figure out which groups we have keys for
# and which we don't
missing_groups = {}
for group in group_id_to_group.values():
for key_id in group.key_ids:
if key_id in merged_results[group.server_name]:
# We now need to figure out which verify requests we have keys
# for and which we don't
missing_keys = {}
requests_missing_keys = []
for verify_request in verify_requests:
server_name = verify_request.server_name
result_keys = merged_results[server_name]
if verify_request.deferred.called:
# We've already called this deferred, which probably
# means that we've already found a key for it.
continue
for key_id in verify_request.key_ids:
if key_id in result_keys:
with PreserveLoggingContext():
group_id_to_deferred[group.group_id].callback((
group.group_id,
group.server_name,
verify_request.deferred.callback((
server_name,
key_id,
merged_results[group.server_name][key_id],
result_keys[key_id],
))
break
else:
missing_groups.setdefault(
group.server_name, []
).append(group)
# The else block is only reached if the loop above
# doesn't break.
missing_keys.setdefault(server_name, set()).update(
verify_request.key_ids
)
requests_missing_keys.append(verify_request)
if not missing_groups:
if not missing_keys:
break
missing_keys = {
server_name: set(
key_id for group in groups for key_id in group.key_ids
)
for server_name, groups in missing_groups.items()
}
for groups in missing_groups.values():
for group in groups:
group_id_to_deferred[group.group_id].errback(SynapseError(
for verify_request in requests_missing_keys.values():
verify_request.deferred.errback(SynapseError(
401,
"No key for %s with id %s" % (
group.server_name, group.key_ids,
verify_request.server_name, verify_request.key_ids,
),
Codes.UNAUTHORIZED,
))
def on_err(err):
for deferred in group_id_to_deferred.values():
if not deferred.called:
deferred.errback(err)
for verify_request in verify_requests:
if not verify_request.deferred.called:
verify_request.deferred.errback(err)
do_iterations().addErrback(on_err)
return group_id_to_deferred
@defer.inlineCallbacks
def get_keys_from_store(self, server_name_and_key_ids):
res = yield defer.gatherResults(