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allow uploading signatures of master key signed by devices

This commit is contained in:
Hubert Chathi 2019-07-17 22:11:31 -04:00
parent 4bb4544784
commit ac4746ac4b
4 changed files with 378 additions and 85 deletions
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232
synapse/handlers/e2e_keys.py
View File

@ -20,7 +20,9 @@ import logging
from six import iteritems
from canonicaljson import encode_canonical_json, json
from signedjson.key import decode_verify_key_bytes
from signedjson.sign import SignatureVerifyException, verify_signed_json
from unpaddedbase64 import decode_base64
from twisted.internet import defer
@ -619,8 +621,11 @@ class E2eKeysHandler(object):
"""
failures = {}
signature_list = [] # signatures to be stored
self_device_ids = [] # what devices have been updated, for notifying
# signatures to be stored. Each item will be a tuple of
# (signing_key_id, target_user_id, target_device_id, signature)
signature_list = []
# what devices have been updated, for notifying
self_device_ids = []
# split between checking signatures for own user and signatures for
# other users, since we verify them with different keys
@ -630,46 +635,107 @@ class E2eKeysHandler(object):
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, self_signing_key_id, self_signing_verify_key \
= yield self._get_e2e_cross_signing_verify_key(
user_id, "self_signing"
)
self_signing_key_id, self_signing_verify_key \
= get_verify_key_from_cross_signing_key(self_signing_key)
# get our master key, since it may be signed
master_key, master_key_id, master_verify_key \
= yield self._get_e2e_cross_signing_verify_key(
user_id, "master"
)
# 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)
# fetch our stored devices. This is used to 1. verify
# signatures on the master key, and 2. to can compare with what
# was sent if the device was signed
devices = yield self.store.get_e2e_device_keys([(user_id, None)])
if user_id not in devices:
raise SynapseError(
404,
"No device key found",
Codes.NOT_FOUND
404, "No device keys 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]):
user_id not in device["signatures"]):
# no signature was sent
raise SynapseError(
400,
"Invalid signature",
Codes.INVALID_SIGNATURE
400, "Invalid signature", Codes.INVALID_SIGNATURE
)
stored_device = devices[device_id]["keys"]
if device_id == master_verify_key.version:
# we have master key signed by devices: for each
# device that signed, check the signature. Since
# the "failures" property in the response only has
# granularity up to the signed device, either all
# of the signatures on the master key succeed, or
# all fail. So loop over the signatures and add
# them to a separate signature list. If everything
# works out, then add them all to the main
# signature list. (In practice, we're likely to
# only have only one signature anyways.)
master_key_signature_list = []
for signing_key_id, signature in device["signatures"][user_id].items():
alg, signing_device_id = signing_key_id.split(":", 1)
if (signing_device_id not in devices or
signing_key_id not in
devices[signing_device_id]["keys"]["keys"]):
# signed by an unknown device, or the
# device does not have the key
raise SynapseError(
400, "Invalid signature", Codes.INVALID_SIGNATURE
)
sigs = device["signatures"]
del device["signatures"]
# use pop to avoid exception if key doesn't exist
device.pop("unsigned", None)
master_key.pop("signature", None)
master_key.pop("unsigned", None)
if master_key != device:
raise SynapseError(
400, "Key does not match"
)
# get the key and check the signature
pubkey = devices[signing_device_id]["keys"]["keys"][signing_key_id]
verify_key = decode_verify_key_bytes(
signing_key_id, decode_base64(pubkey)
)
device["signatures"] = sigs
try:
verify_signed_json(device, user_id, verify_key)
except SignatureVerifyException:
raise SynapseError(
400, "Invalid signature", Codes.INVALID_SIGNATURE
)
master_key_signature_list.append(
(signing_key_id, user_id, device_id, signature)
)
signature_list.extend(master_key_signature_list)
continue
# at this point, we have a device that should be signed
# by the self-signing key
if self_signing_key_id not in device["signatures"][user_id]:
# no signature was sent
raise SynapseError(
400, "Invalid signature", Codes.INVALID_SIGNATURE
)
stored_device = None
try:
stored_device = devices[device_id]["keys"]
except KeyError:
raise SynapseError(
404, "Unknown device", Codes.NOT_FOUND
)
if self_signing_key_id in stored_device.get("signatures", {}) \
.get(user_id, {}):
# we already have a signature on this device, so we
@ -698,69 +764,50 @@ class E2eKeysHandler(object):
# 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)
try:
# get our user-signing key to verify the signatures
user_signing_key, user_signing_key_id, user_signing_verify_key \
= yield self._get_e2e_cross_signing_verify_key(
user_id, "user_signing"
)
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
stored_key, stored_key_id, _ \
= yield self._get_e2e_cross_signing_verify_key(
user, "master", user_id
)
# 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]
device_id = stored_key_id.split(":", 1)[1]
if device_id not in devicemap:
# set device to None so that the failure gets
# marked on all the signatures
device_id = None
logger.error(
"upload signature: wrong device: %s vs %s",
device, devicemap
)
raise SynapseError(
404,
"Unknown device",
Codes.NOT_FOUND
404, "Unknown device", Codes.NOT_FOUND
)
if len(devicemap) > 1:
key = devicemap[device_id]
del devicemap[device_id]
if len(devicemap) > 0:
# other devices were signed -- mark those as failures
logger.error("upload signature: too many devices specified")
failure = _exception_to_failure(SynapseError(
404, "Unknown device", Codes.NOT_FOUND
))
failures[user] = {
device: _exception_to_failure(SynapseError(
404,
"Unknown device",
Codes.NOT_FOUND
))
device: failure
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
@ -770,25 +817,31 @@ class E2eKeysHandler(object):
user_id, user_signing_verify_key, key, stored_key
)
signature = key["signatures"][user_id][user_signing_key_id]
signed_users.append(user)
signature = key["signatures"][user_id][user_signing_key_id]
signature_list.append(
(user_signing_key_id, user, device_id, signature)
)
except SynapseError as e:
failure = _exception_to_failure(e)
if device_id is None:
failures[user] = {
device_id: _exception_to_failure(e)
device_id: failure
for device_id in devicemap.keys()
}
else:
failures.setdefault(user, {})[device_id] \
= _exception_to_failure(e)
failures.setdefault(user, {})[device_id] = failure
except SynapseError as e:
failure = _exception_to_failure(e)
for user, devicemap in signature.items():
failures[user] = {
device_id: failure
for device_id in devicemap.keys()
}
# 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)
yield self.store.store_e2e_cross_signing_signatures(user_id, signature_list)
if len(self_device_ids):
yield self.device_handler.notify_device_update(user_id, self_device_ids)
@ -797,6 +850,22 @@ class E2eKeysHandler(object):
defer.returnValue({"failures": failures})
@defer.inlineCallbacks
def _get_e2e_cross_signing_verify_key(self, user_id, key_type, from_user_id=None):
key = yield self.store.get_e2e_cross_signing_key(
user_id, key_type, from_user_id
)
if key is None:
logger.error("no %s key found for %s", key_type, user_id)
raise SynapseError(
404,
"No %s key found for %s" % (key_type, user_id),
Codes.NOT_FOUND
)
key_id, verify_key = get_verify_key_from_cross_signing_key(key)
return key, key_id, verify_key
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
checking, and ensures that it is signed, if a signature is required.
@ -851,21 +920,17 @@ def _check_device_signature(user_id, verify_key, signed_device, stored_device):
# 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"]
# use pop to avoid exception if key doesn't exist
signed_device.pop("unsigned", None)
stored_device.pop("signatures", None)
stored_device.pop("unsigned", None)
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"
400, "Key does not match",
)
# check the signature
@ -887,6 +952,9 @@ def _check_device_signature(user_id, verify_key, signed_device, stored_device):
def _exception_to_failure(e):
if isinstance(e, SynapseError):
return {"status": e.code, "errcode": e.errcode, "message": str(e)}
if isinstance(e, CodeMessageException):
return {"status": e.code, "message": str(e)}

2
synapse/rest/client/v2_alpha/keys.py
View File

@ -303,7 +303,7 @@ class SignaturesUploadServlet(RestServlet):
}
}
"""
PATTERNS = client_v2_patterns("/keys/signatures/upload$")
PATTERNS = client_patterns("/keys/signatures/upload$")
def __init__(self, hs):
"""

2
synapse/storage/end_to_end_keys.py
View File

@ -132,7 +132,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
# get signatures on the device
signature_sql = (
"SELECT * "
" FROM e2e_device_signatures "
" FROM e2e_cross_signing_signatures "
" WHERE %s"
) % (
" OR ".join("(" + q + ")" for q in signature_query_clauses)

227
tests/handlers/test_e2e_keys.py
View File

@ -17,9 +17,10 @@
import mock
import signedjson.key as key
import signedjson.sign as sign
from twisted.internet import defer
import synapse.api.errors
import synapse.handlers.e2e_keys
import synapse.storage
from synapse.api import errors
@ -210,3 +211,227 @@ class E2eKeysHandlerTestCase(unittest.TestCase):
res = yield self.handler.query_local_devices({local_user: None})
self.assertDictEqual(res, {local_user: {}})
@defer.inlineCallbacks
def test_upload_signatures(self):
"""should check signatures that are uploaded"""
# set up a user with cross-signing keys and a device. This user will
# try uploading signatures
local_user = "@boris:" + self.hs.hostname
device_id = "xyz"
# private key: OMkooTr76ega06xNvXIGPbgvvxAOzmQncN8VObS7aBA
device_pubkey = "NnHhnqiMFQkq969szYkooLaBAXW244ZOxgukCvm2ZeY"
device_key = {
"user_id": local_user,
"device_id": device_id,
"algorithms": ["m.olm.curve25519-aes-sha256", "m.megolm.v1.aes-sha"],
"keys": {
"curve25519:xyz": "curve25519+key",
"ed25519:xyz": device_pubkey
},
"signatures": {
local_user: {
"ed25519:xyz": "something"
}
}
}
device_signing_key = key.decode_signing_key_base64(
"ed25519",
"xyz",
"OMkooTr76ega06xNvXIGPbgvvxAOzmQncN8VObS7aBA"
)
yield self.handler.upload_keys_for_user(
local_user, device_id, {"device_keys": device_key}
)
# private key: 2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0
master_pubkey = "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk"
master_key = {
"user_id": local_user,
"usage": ["master"],
"keys": {
"ed25519:" + master_pubkey: master_pubkey
}
}
master_signing_key = key.decode_signing_key_base64(
"ed25519", master_pubkey,
"2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0"
)
usersigning_pubkey = "Hq6gL+utB4ET+UvD5ci0kgAwsX6qP/zvf8v6OInU5iw"
usersigning_key = {
# private key: 4TL4AjRYwDVwD3pqQzcor+ez/euOB1/q78aTJ+czDNs
"user_id": local_user,
"usage": ["user_signing"],
"keys": {
"ed25519:" + usersigning_pubkey: usersigning_pubkey,
}
}
usersigning_signing_key = key.decode_signing_key_base64(
"ed25519", usersigning_pubkey,
"4TL4AjRYwDVwD3pqQzcor+ez/euOB1/q78aTJ+czDNs"
)
sign.sign_json(usersigning_key, local_user, master_signing_key)
# private key: HvQBbU+hc2Zr+JP1sE0XwBe1pfZZEYtJNPJLZJtS+F8
selfsigning_pubkey = "EmkqvokUn8p+vQAGZitOk4PWjp7Ukp3txV2TbMPEiBQ"
selfsigning_key = {
"user_id": local_user,
"usage": ["self_signing"],
"keys": {
"ed25519:" + selfsigning_pubkey: selfsigning_pubkey,
}
}
selfsigning_signing_key = key.decode_signing_key_base64(
"ed25519", selfsigning_pubkey,
"HvQBbU+hc2Zr+JP1sE0XwBe1pfZZEYtJNPJLZJtS+F8"
)
sign.sign_json(selfsigning_key, local_user, master_signing_key)
cross_signing_keys = {
"master_key": master_key,
"user_signing_key": usersigning_key,
"self_signing_key": selfsigning_key,
}
yield self.handler.upload_signing_keys_for_user(local_user, cross_signing_keys)
# set up another user with a master key. This user will be signed by
# the first user
other_user = "@otherboris:" + self.hs.hostname
other_master_pubkey = "fHZ3NPiKxoLQm5OoZbKa99SYxprOjNs4TwJUKP+twCM"
other_master_key = {
# private key: oyw2ZUx0O4GifbfFYM0nQvj9CL0b8B7cyN4FprtK8OI
"user_id": other_user,
"usage": ["master"],
"keys": {
"ed25519:" + other_master_pubkey: other_master_pubkey
}
}
yield self.handler.upload_signing_keys_for_user(other_user, {
"master_key": other_master_key
})
# test various signature failures (see below)
ret = yield self.handler.upload_signatures_for_device_keys(
local_user,
{
local_user: {
# fails because the signature is invalid
# should fail with INVALID_SIGNATURE
device_id: {
"user_id": local_user,
"device_id": device_id,
"algorithms": ["m.olm.curve25519-aes-sha256", "m.megolm.v1.aes-sha"],
"keys": {
"curve25519:xyz": "curve25519+key",
# private key: OMkooTr76ega06xNvXIGPbgvvxAOzmQncN8VObS7aBA
"ed25519:xyz": device_pubkey
},
"signatures": {
local_user: {
"ed25519:" + selfsigning_pubkey: "something",
}
}
},
# fails because device is unknown
# should fail with NOT_FOUND
"unknown": {
"user_id": local_user,
"device_id": "unknown",
"signatures": {
local_user: {
"ed25519:" + selfsigning_pubkey: "something",
}
}
},
# fails because the signature is invalid
# should fail with INVALID_SIGNATURE
master_pubkey: {
"user_id": local_user,
"usage": ["master"],
"keys": {
"ed25519:" + master_pubkey: master_pubkey
},
"signatures": {
local_user: {
"ed25519:" + device_pubkey: "something",
}
}
}
},
other_user: {
# fails because the device is not the user's master-signing key
# should fail with NOT_FOUND
"unknown": {
"user_id": other_user,
"device_id": "unknown",
"signatures": {
local_user: {
"ed25519:" + usersigning_pubkey: "something",
}
}
},
other_master_pubkey: {
# fails because the key doesn't match what the server has
# should fail with UNKNOWN
"user_id": other_user,
"usage": ["master"],
"keys": {
"ed25519:" + other_master_pubkey: other_master_pubkey
},
"something": "random",
"signatures": {
local_user: {
"ed25519:" + usersigning_pubkey: "something",
}
}
}
}
}
)
user_failures = ret["failures"][local_user]
self.assertEqual(user_failures[device_id]["errcode"], errors.Codes.INVALID_SIGNATURE)
self.assertEqual(user_failures[master_pubkey]["errcode"], errors.Codes.INVALID_SIGNATURE)
self.assertEqual(user_failures["unknown"]["errcode"], errors.Codes.NOT_FOUND)
other_user_failures = ret["failures"][other_user]
self.assertEqual(other_user_failures["unknown"]["errcode"], errors.Codes.NOT_FOUND)
self.assertEqual(other_user_failures[other_master_pubkey]["errcode"], errors.Codes.UNKNOWN)
# test successful signatures
del device_key["signatures"]
sign.sign_json(device_key, local_user, selfsigning_signing_key)
sign.sign_json(master_key, local_user, device_signing_key)
sign.sign_json(other_master_key, local_user, usersigning_signing_key)
ret = yield self.handler.upload_signatures_for_device_keys(
local_user,
{
local_user: {
device_id: device_key,
master_pubkey: master_key
},
other_user: {
other_master_pubkey: other_master_key
}
}
)
self.assertEqual(ret["failures"], {})
# fetch the signed keys/devices and make sure that the signatures are there
ret = yield self.handler.query_devices(
{"device_keys": {local_user: [], other_user: []}},
0, local_user
)
self.assertEqual(
ret["device_keys"][local_user]["xyz"]["signatures"][local_user]["ed25519:" + selfsigning_pubkey],
device_key["signatures"][local_user]["ed25519:" + selfsigning_pubkey]
)
self.assertEqual(
ret["master_keys"][local_user]["signatures"][local_user]["ed25519:" + device_id],
master_key["signatures"][local_user]["ed25519:" + device_id]
)
self.assertEqual(
ret["master_keys"][other_user]["signatures"][local_user]["ed25519:" + usersigning_pubkey],
other_master_key["signatures"][local_user]["ed25519:" + usersigning_pubkey]
)