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implement device signature uploading/fetching

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This commit is contained in:
Hubert Chathi 2019-05-22 16:41:24 -04:00
parent a22d58c96c
commit 4bb4544784
3 changed files with 338 additions and 0 deletions
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250
synapse/handlers/e2e_keys.py
View file

@ -608,6 +608,194 @@ class E2eKeysHandler(object):
return {}
@defer.inlineCallbacks
def upload_signatures_for_device_keys(self, user_id, signatures):
"""Upload device signatures for cross-signing
Args:
user_id (string): the user uploading the signatures
signatures (dict[string, dict[string, dict]]): map of users to
devices to signed keys
"""
failures = {}
signature_list = [] # signatures to be stored
self_device_ids = [] # what devices have been updated, for notifying
# split between checking signatures for own user and signatures for
# other users, since we verify them with different keys
if user_id in signatures:
self_signatures = signatures[user_id]
del signatures[user_id]
self_device_ids = list(self_signatures.keys())
try:
# get our self-signing key to verify the signatures
self_signing_key = yield self.store.get_e2e_cross_signing_key(
user_id, "self_signing"
)
if self_signing_key is None:
raise SynapseError(
404,
"No self-signing key found",
Codes.NOT_FOUND
)
self_signing_key_id, self_signing_verify_key \
= get_verify_key_from_cross_signing_key(self_signing_key)
# fetch our stored devices so that we can compare with what was sent
user_devices = []
for device in self_signatures.keys():
user_devices.append((user_id, device))
devices = yield self.store.get_e2e_device_keys(user_devices)
if user_id not in devices:
raise SynapseError(
404,
"No device key found",
Codes.NOT_FOUND
)
devices = devices[user_id]
for device_id, device in self_signatures.items():
try:
if ("signatures" not in device or
user_id not in device["signatures"] or
self_signing_key_id not in device["signatures"][user_id]):
# no signature was sent
raise SynapseError(
400,
"Invalid signature",
Codes.INVALID_SIGNATURE
)
stored_device = devices[device_id]["keys"]
if self_signing_key_id in stored_device.get("signatures", {}) \
.get(user_id, {}):
# we already have a signature on this device, so we
# can skip it, since it should be exactly the same
continue
_check_device_signature(
user_id, self_signing_verify_key, device, stored_device
)
signature = device["signatures"][user_id][self_signing_key_id]
signature_list.append(
(self_signing_key_id, user_id, device_id, signature)
)
except SynapseError as e:
failures.setdefault(user_id, {})[device_id] \
= _exception_to_failure(e)
except SynapseError as e:
failures[user_id] = {
device: _exception_to_failure(e)
for device in self_signatures.keys()
}
signed_users = [] # what user have been signed, for notifying
if len(signatures):
# if signatures isn't empty, then we have signatures for other
# users. These signatures will be signed by the user signing key
# get our user-signing key to verify the signatures
user_signing_key = yield self.store.get_e2e_cross_signing_key(
user_id, "user_signing"
)
if user_signing_key is None:
for user, devicemap in signatures.items():
failures[user] = {
device: _exception_to_failure(SynapseError(
404,
"No user-signing key found",
Codes.NOT_FOUND
))
for device in devicemap.keys()
}
else:
user_signing_key_id, user_signing_verify_key \
= get_verify_key_from_cross_signing_key(user_signing_key)
for user, devicemap in signatures.items():
device_id = None
try:
# get the user's master key, to make sure it matches
# what was sent
stored_key = yield self.store.get_e2e_cross_signing_key(
user, "master", user_id
)
if stored_key is None:
logger.error(
"upload signature: no user key found for %s", user
)
raise SynapseError(
404,
"User's master key not found",
Codes.NOT_FOUND
)
# make sure that the user's master key is the one that
# was signed (and no others)
device_id = get_verify_key_from_cross_signing_key(stored_key)[0] \
.split(":", 1)[1]
if device_id not in devicemap:
logger.error(
"upload signature: wrong device: %s vs %s",
device, devicemap
)
raise SynapseError(
404,
"Unknown device",
Codes.NOT_FOUND
)
if len(devicemap) > 1:
logger.error("upload signature: too many devices specified")
failures[user] = {
device: _exception_to_failure(SynapseError(
404,
"Unknown device",
Codes.NOT_FOUND
))
for device in devicemap.keys()
}
key = devicemap[device_id]
if user_signing_key_id in stored_key.get("signatures", {}) \
.get(user_id, {}):
# we already have the signature, so we can skip it
continue
_check_device_signature(
user_id, user_signing_verify_key, key, stored_key
)
signature = key["signatures"][user_id][user_signing_key_id]
signed_users.append(user)
signature_list.append(
(user_signing_key_id, user, device_id, signature)
)
except SynapseError as e:
if device_id is None:
failures[user] = {
device_id: _exception_to_failure(e)
for device_id in devicemap.keys()
}
else:
failures.setdefault(user, {})[device_id] \
= _exception_to_failure(e)
# store the signature, and send the appropriate notifications for sync
logger.debug("upload signature failures: %r", failures)
yield self.store.store_e2e_device_signatures(user_id, signature_list)
if len(self_device_ids):
yield self.device_handler.notify_device_update(user_id, self_device_ids)
if len(signed_users):
yield self.device_handler.notify_user_signature_update(user_id, signed_users)
defer.returnValue({"failures": failures})
def _check_cross_signing_key(key, user_id, key_type, signing_key=None):
"""Check a cross-signing key uploaded by a user. Performs some basic sanity
@ -636,6 +824,68 @@ def _check_cross_signing_key(key, user_id, key_type, signing_key=None):
)
def _check_device_signature(user_id, verify_key, signed_device, stored_device):
"""Check that a device signature is correct and matches the copy of the device
that we have. Throws an exception if an error is detected.
Args:
user_id (str): the user ID whose signature is being checked
verify_key (VerifyKey): the key to verify the device with
signed_device (dict): the signed device data
stored_device (dict): our previous copy of the device
"""
key_id = "%s:%s" % (verify_key.alg, verify_key.version)
# make sure the device is signed
if ("signatures" not in signed_device or user_id not in signed_device["signatures"]
or key_id not in signed_device["signatures"][user_id]):
logger.error("upload signature: user not found in signatures")
raise SynapseError(
400,
"Invalid signature",
Codes.INVALID_SIGNATURE
)
signature = signed_device["signatures"][user_id][key_id]
# make sure that the device submitted matches what we have stored
del signed_device["signatures"]
if "unsigned" in signed_device:
del signed_device["unsigned"]
if "signatures" in stored_device:
del stored_device["signatures"]
if "unsigned" in stored_device:
del stored_device["unsigned"]
if signed_device != stored_device:
logger.error(
"upload signatures: key does not match %s vs %s",
signed_device, stored_device
)
raise SynapseError(
400,
"Key does not match",
"M_MISMATCHED_KEY"
)
# check the signature
signed_device["signatures"] = {
user_id: {
key_id: signature
}
}
try:
verify_signed_json(signed_device, user_id, verify_key)
except SignatureVerifyException:
logger.error("invalid signature on key")
raise SynapseError(
400,
"Invalid signature",
Codes.INVALID_SIGNATURE
)
def _exception_to_failure(e):
if isinstance(e, CodeMessageException):
return {"status": e.code, "message": str(e)}

50
synapse/rest/client/v2_alpha/keys.py
View file

@ -277,9 +277,59 @@ class SigningKeyUploadServlet(RestServlet):
return (200, result)
class SignaturesUploadServlet(RestServlet):
"""
POST /keys/signatures/upload HTTP/1.1
Content-Type: application/json
{
"@alice:example.com": {
"<device_id>": {
"user_id": "<user_id>",
"device_id": "<device_id>",
"algorithms": [
"m.olm.curve25519-aes-sha256",
"m.megolm.v1.aes-sha"
],
"keys": {
"<algorithm>:<device_id>": "<key_base64>",
},
"signatures": {
"<signing_user_id>": {
"<algorithm>:<signing_key_base64>": "<signature_base64>>"
}
}
}
}
}
"""
PATTERNS = client_v2_patterns("/keys/signatures/upload$")
def __init__(self, hs):
"""
Args:
hs (synapse.server.HomeServer): server
"""
super(SignaturesUploadServlet, self).__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
@defer.inlineCallbacks
def on_POST(self, request):
requester = yield self.auth.get_user_by_req(request, allow_guest=True)
user_id = requester.user.to_string()
body = parse_json_object_from_request(request)
result = yield self.e2e_keys_handler.upload_signatures_for_device_keys(
user_id, body
)
defer.returnValue((200, result))
def register_servlets(hs, http_server):
KeyUploadServlet(hs).register(http_server)
KeyQueryServlet(hs).register(http_server)
KeyChangesServlet(hs).register(http_server)
OneTimeKeyServlet(hs).register(http_server)
SigningKeyUploadServlet(hs).register(http_server)
SignaturesUploadServlet(hs).register(http_server)

38
synapse/storage/end_to_end_keys.py
View file

@ -59,6 +59,12 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
for user_id, device_keys in iteritems(results):
for device_id, device_info in iteritems(device_keys):
device_info["keys"] = db_to_json(device_info.pop("key_json"))
# add cross-signing signatures to the keys
if "signatures" in device_info:
for sig_user_id, sigs in device_info["signatures"].items():
device_info["keys"].setdefault("signatures", {}) \
.setdefault(sig_user_id, {}) \
.update(sigs)
return results
@ -71,6 +77,8 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
query_clauses = []
query_params = []
signature_query_clauses = []
signature_query_params = []
if include_all_devices is False:
include_deleted_devices = False
@ -81,12 +89,20 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
for (user_id, device_id) in query_list:
query_clause = "user_id = ?"
query_params.append(user_id)
signature_query_clause = "target_user_id = ?"
signature_query_params.append(user_id)
if device_id is not None:
query_clause += " AND device_id = ?"
query_params.append(device_id)
signature_query_clause += " AND target_device_id = ?"
signature_query_params.append(device_id)
signature_query_clause += " AND user_id = ?"
signature_query_params.append(user_id)
query_clauses.append(query_clause)
signature_query_clauses.append(signature_query_clause)
sql = (
"SELECT user_id, device_id, "
@ -113,6 +129,28 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
for user_id, device_id in deleted_devices:
result.setdefault(user_id, {})[device_id] = None
# get signatures on the device
signature_sql = (
"SELECT * "
" FROM e2e_device_signatures "
" WHERE %s"
) % (
" OR ".join("(" + q + ")" for q in signature_query_clauses)
)
txn.execute(signature_sql, signature_query_params)
rows = self.cursor_to_dict(txn)
for row in rows:
target_user_id = row["target_user_id"]
target_device_id = row["target_device_id"]
if target_user_id in result \
and target_device_id in result[target_user_id]:
result[target_user_id][target_device_id] \
.setdefault("signatures", {}) \
.setdefault(row["user_id"], {})[row["key_id"]] \
= row["signature"]
log_kv(result)
return result