synapse/tests/handlers/test_e2e_keys.py

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2019 The Matrix.org Foundation C.I.C.
# Copyright 2016 OpenMarket Ltd
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
from typing import Dict, Iterable
from unittest import mock

from parameterized import parameterized
from signedjson import key as key, sign as sign

from twisted.test.proto_helpers import MemoryReactor

from synapse.api.constants import RoomEncryptionAlgorithms
from synapse.api.errors import Codes, SynapseError
from synapse.appservice import ApplicationService
from synapse.handlers.device import DeviceHandler
from synapse.server import HomeServer
from synapse.storage.databases.main.appservice import _make_exclusive_regex
from synapse.types import JsonDict, UserID
from synapse.util import Clock

from tests import unittest
from tests.unittest import override_config


class E2eKeysHandlerTestCase(unittest.HomeserverTestCase):
    def make_homeserver(self, reactor: MemoryReactor, clock: Clock) -> HomeServer:
        self.appservice_api = mock.AsyncMock()
        return self.setup_test_homeserver(application_service_api=self.appservice_api)

    def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
        self.handler = hs.get_e2e_keys_handler()
        self.store = self.hs.get_datastores().main
        self.requester = UserID.from_string(f"@test_requester:{self.hs.hostname}")

    def test_query_local_devices_no_devices(self) -> None:
        """If the user has no devices, we expect an empty list."""
        local_user = "@boris:" + self.hs.hostname
        res = self.get_success(self.handler.query_local_devices({local_user: None}))
        self.assertDictEqual(res, {local_user: {}})

    def test_reupload_one_time_keys(self) -> None:
        """we should be able to re-upload the same keys"""
        local_user = "@boris:" + self.hs.hostname
        device_id = "xyz"
        keys: JsonDict = {
            "alg1:k1": "key1",
            "alg2:k2": {"key": "key2", "signatures": {"k1": "sig1"}},
            "alg2:k3": {"key": "key3"},
        }

        # Note that "signed_curve25519" is always returned in key count responses. This is necessary until
        # https://github.com/matrix-org/matrix-doc/issues/3298 is fixed.
        res = self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": keys}
            )
        )
        self.assertDictEqual(
            res, {"one_time_key_counts": {"alg1": 1, "alg2": 2, "signed_curve25519": 0}}
        )

        # we should be able to change the signature without a problem
        keys["alg2:k2"]["signatures"]["k1"] = "sig2"
        res = self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": keys}
            )
        )
        self.assertDictEqual(
            res, {"one_time_key_counts": {"alg1": 1, "alg2": 2, "signed_curve25519": 0}}
        )

    def test_change_one_time_keys(self) -> None:
        """attempts to change one-time-keys should be rejected"""

        local_user = "@boris:" + self.hs.hostname
        device_id = "xyz"
        keys = {
            "alg1:k1": "key1",
            "alg2:k2": {"key": "key2", "signatures": {"k1": "sig1"}},
            "alg2:k3": {"key": "key3"},
        }

        res = self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": keys}
            )
        )
        self.assertDictEqual(
            res, {"one_time_key_counts": {"alg1": 1, "alg2": 2, "signed_curve25519": 0}}
        )

        # Error when changing string key
        self.get_failure(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": {"alg1:k1": "key2"}}
            ),
            SynapseError,
        )

        # Error when replacing dict key with string
        self.get_failure(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": {"alg2:k3": "key2"}}
            ),
            SynapseError,
        )

        # Error when replacing string key with dict
        self.get_failure(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"one_time_keys": {"alg1:k1": {"key": "key"}}},
            ),
            SynapseError,
        )

        # Error when replacing dict key
        self.get_failure(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {
                    "one_time_keys": {
                        "alg2:k2": {"key": "key3", "signatures": {"k1": "sig1"}}
                    }
                },
            ),
            SynapseError,
        )

    def test_claim_one_time_key(self) -> None:
        local_user = "@boris:" + self.hs.hostname
        device_id = "xyz"
        keys = {"alg1:k1": "key1"}

        res = self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": keys}
            )
        )
        self.assertDictEqual(
            res, {"one_time_key_counts": {"alg1": 1, "signed_curve25519": 0}}
        )

        res2 = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            res2,
            {
                "failures": {},
                "one_time_keys": {local_user: {device_id: {"alg1:k1": "key1"}}},
            },
        )

    def test_claim_one_time_key_bulk(self) -> None:
        """Like test_claim_one_time_key but claims multiple keys in one handler call."""
        # Apologies to the reader. This test is a little too verbose. It is particularly
        # tricky to make assertions neatly with all these nested dictionaries in play.

        # Three users with two devices each. Each device uses two algorithms.
        # Each algorithm is invoked with two keys.
        alice = f"@alice:{self.hs.hostname}"
        brian = f"@brian:{self.hs.hostname}"
        chris = f"@chris:{self.hs.hostname}"
        one_time_keys = {
            alice: {
                "alice_dev_1": {
                    "alg1:k1": {"dummy_id": 1},
                    "alg1:k2": {"dummy_id": 2},
                    "alg2:k3": {"dummy_id": 3},
                    "alg2:k4": {"dummy_id": 4},
                },
                "alice_dev_2": {
                    "alg1:k5": {"dummy_id": 5},
                    "alg1:k6": {"dummy_id": 6},
                    "alg2:k7": {"dummy_id": 7},
                    "alg2:k8": {"dummy_id": 8},
                },
            },
            brian: {
                "brian_dev_1": {
                    "alg1:k9": {"dummy_id": 9},
                    "alg1:k10": {"dummy_id": 10},
                    "alg2:k11": {"dummy_id": 11},
                    "alg2:k12": {"dummy_id": 12},
                },
                "brian_dev_2": {
                    "alg1:k13": {"dummy_id": 13},
                    "alg1:k14": {"dummy_id": 14},
                    "alg2:k15": {"dummy_id": 15},
                    "alg2:k16": {"dummy_id": 16},
                },
            },
            chris: {
                "chris_dev_1": {
                    "alg1:k17": {"dummy_id": 17},
                    "alg1:k18": {"dummy_id": 18},
                    "alg2:k19": {"dummy_id": 19},
                    "alg2:k20": {"dummy_id": 20},
                },
                "chris_dev_2": {
                    "alg1:k21": {"dummy_id": 21},
                    "alg1:k22": {"dummy_id": 22},
                    "alg2:k23": {"dummy_id": 23},
                    "alg2:k24": {"dummy_id": 24},
                },
            },
        }
        for user_id, devices in one_time_keys.items():
            for device_id, keys_dict in devices.items():
                counts = self.get_success(
                    self.handler.upload_keys_for_user(
                        user_id,
                        device_id,
                        {"one_time_keys": keys_dict},
                    )
                )
                # The upload should report 2 keys per algorithm.
                expected_counts = {
                    "one_time_key_counts": {
                        # See count_e2e_one_time_keys for why this is hardcoded.
                        "signed_curve25519": 0,
                        "alg1": 2,
                        "alg2": 2,
                    },
                }
                self.assertEqual(counts, expected_counts)

        # Claim a variety of keys.
        # Raw format, easier to make test assertions about.
        claims_to_make = {
            (alice, "alice_dev_1", "alg1"): 1,
            (alice, "alice_dev_1", "alg2"): 2,
            (alice, "alice_dev_2", "alg2"): 1,
            (brian, "brian_dev_1", "alg1"): 2,
            (brian, "brian_dev_2", "alg2"): 9001,
            (chris, "chris_dev_2", "alg2"): 1,
        }
        # Convert to the format the handler wants.
        query: Dict[str, Dict[str, Dict[str, int]]] = {}
        for (user_id, device_id, algorithm), count in claims_to_make.items():
            query.setdefault(user_id, {}).setdefault(device_id, {})[algorithm] = count
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                query,
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )

        # No failures, please!
        self.assertEqual(claim_res["failures"], {})

        # Check that we get exactly the (user, device, algorithm)s we asked for.
        got_otks = claim_res["one_time_keys"]
        claimed_user_device_algorithms = {
            (user_id, device_id, alg_key_id.split(":")[0])
            for user_id, devices in got_otks.items()
            for device_id, key_dict in devices.items()
            for alg_key_id in key_dict
        }
        self.assertEqual(claimed_user_device_algorithms, set(claims_to_make))

        # Now check the keys we got are what we expected.
        def assertExactlyOneOtk(
            user_id: str, device_id: str, *alg_key_pairs: str
        ) -> None:
            key_dict = got_otks[user_id][device_id]
            found = 0
            for alg_key in alg_key_pairs:
                if alg_key in key_dict:
                    expected_key_json = one_time_keys[user_id][device_id][alg_key]
                    self.assertEqual(key_dict[alg_key], expected_key_json)
                    found += 1
            self.assertEqual(found, 1)

        def assertAllOtks(user_id: str, device_id: str, *alg_key_pairs: str) -> None:
            key_dict = got_otks[user_id][device_id]
            for alg_key in alg_key_pairs:
                expected_key_json = one_time_keys[user_id][device_id][alg_key]
                self.assertEqual(key_dict[alg_key], expected_key_json)

        # Expect a single arbitrary key to be returned.
        assertExactlyOneOtk(alice, "alice_dev_1", "alg1:k1", "alg1:k2")
        assertExactlyOneOtk(alice, "alice_dev_2", "alg2:k7", "alg2:k8")
        assertExactlyOneOtk(chris, "chris_dev_2", "alg2:k23", "alg2:k24")

        assertAllOtks(alice, "alice_dev_1", "alg2:k3", "alg2:k4")
        assertAllOtks(brian, "brian_dev_1", "alg1:k9", "alg1:k10")
        assertAllOtks(brian, "brian_dev_2", "alg2:k15", "alg2:k16")

        # Now check the unused key counts.
        for user_id, devices in one_time_keys.items():
            for device_id in devices:
                counts_by_alg = self.get_success(
                    self.store.count_e2e_one_time_keys(user_id, device_id)
                )
                # Somewhat fiddley to compute the expected count dict.
                expected_counts_by_alg = {
                    "signed_curve25519": 0,
                }
                for alg in ["alg1", "alg2"]:
                    claim_count = claims_to_make.get((user_id, device_id, alg), 0)
                    remaining_count = max(0, 2 - claim_count)
                    if remaining_count > 0:
                        expected_counts_by_alg[alg] = remaining_count

                self.assertEqual(
                    counts_by_alg, expected_counts_by_alg, f"{user_id}:{device_id}"
                )

    def test_fallback_key(self) -> None:
        local_user = "@boris:" + self.hs.hostname
        device_id = "xyz"
        fallback_key = {"alg1:k1": "fallback_key1"}
        fallback_key2 = {"alg1:k2": "fallback_key2"}
        fallback_key3 = {"alg1:k2": "fallback_key3"}
        otk = {"alg1:k2": "key2"}

        # we shouldn't have any unused fallback keys yet
        res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(res, [])

        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"fallback_keys": fallback_key},
            )
        )

        # we should now have an unused alg1 key
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # claiming an OTK when no OTKs are available should return the fallback
        # key
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
        )

        # we shouldn't have any unused fallback keys again
        unused_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(unused_res, [])

        # claiming an OTK again should return the same fallback key
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
        )

        # re-uploading the same fallback key should still result in no unused fallback
        # keys
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"fallback_keys": fallback_key},
            )
        )

        unused_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(unused_res, [])

        # uploading a new fallback key should result in an unused fallback key
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"fallback_keys": fallback_key2},
            )
        )

        unused_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(unused_res, ["alg1"])

        # if the user uploads a one-time key, the next claim should fetch the
        # one-time key, and then go back to the fallback
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_id, {"one_time_keys": otk}
            )
        )

        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: otk}}},
        )

        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key2}}},
        )

        # using the unstable prefix should also set the fallback key
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"org.matrix.msc2732.fallback_keys": fallback_key3},
            )
        )

        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key3}}},
        )

    def test_fallback_key_bulk(self) -> None:
        """Like test_fallback_key, but claims multiple keys in one handler call."""
        alice = f"@alice:{self.hs.hostname}"
        brian = f"@brian:{self.hs.hostname}"
        chris = f"@chris:{self.hs.hostname}"

        # Have three users upload fallback keys for two devices.
        fallback_keys = {
            alice: {
                "alice_dev_1": {"alg1:k1": "fallback_key1"},
                "alice_dev_2": {"alg2:k2": "fallback_key2"},
            },
            brian: {
                "brian_dev_1": {"alg1:k3": "fallback_key3"},
                "brian_dev_2": {"alg2:k4": "fallback_key4"},
            },
            chris: {
                "chris_dev_1": {"alg1:k5": "fallback_key5"},
                "chris_dev_2": {"alg2:k6": "fallback_key6"},
            },
        }

        for user_id, devices in fallback_keys.items():
            for device_id, key_dict in devices.items():
                self.get_success(
                    self.handler.upload_keys_for_user(
                        user_id,
                        device_id,
                        {"fallback_keys": key_dict},
                    )
                )

        # Each device should have an unused fallback key.
        for user_id, devices in fallback_keys.items():
            for device_id in devices:
                fallback_res = self.get_success(
                    self.store.get_e2e_unused_fallback_key_types(user_id, device_id)
                )
                expected_algorithm_name = f"alg{device_id[-1]}"
                self.assertEqual(fallback_res, [expected_algorithm_name])

        # Claim the fallback key for one device per user.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {
                    alice: {"alice_dev_1": {"alg1": 1}},
                    brian: {"brian_dev_2": {"alg2": 1}},
                    chris: {"chris_dev_2": {"alg2": 1}},
                },
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        expected_claims = {
            alice: {"alice_dev_1": {"alg1:k1": "fallback_key1"}},
            brian: {"brian_dev_2": {"alg2:k4": "fallback_key4"}},
            chris: {"chris_dev_2": {"alg2:k6": "fallback_key6"}},
        }
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": expected_claims},
        )

        for user_id, devices in fallback_keys.items():
            for device_id in devices:
                fallback_res = self.get_success(
                    self.store.get_e2e_unused_fallback_key_types(user_id, device_id)
                )
                # Claimed fallback keys should no longer show up as unused.
                # Unclaimed fallback keys should still be unused.
                if device_id in expected_claims[user_id]:
                    self.assertEqual(fallback_res, [])
                else:
                    expected_algorithm_name = f"alg{device_id[-1]}"
                    self.assertEqual(fallback_res, [expected_algorithm_name])

    def test_fallback_key_always_returned(self) -> None:
        local_user = "@boris:" + self.hs.hostname
        device_id = "xyz"
        fallback_key = {"alg1:k1": "fallback_key1"}
        otk = {"alg1:k2": "key2"}

        # we shouldn't have any unused fallback keys yet
        res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(res, [])

        # Upload a OTK & fallback key.
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id,
                {"one_time_keys": otk, "fallback_keys": fallback_key},
            )
        )

        # we should now have an unused alg1 key
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # Claiming an OTK and requesting to always return the fallback key should
        # return both.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {local_user: {device_id: {**fallback_key, **otk}}},
            },
        )

        # This should not mark the key as used.
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # Claiming an OTK again should return only the fallback key.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {"failures": {}, "one_time_keys": {local_user: {device_id: fallback_key}}},
        )

        # And mark it as used.
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id)
        )
        self.assertEqual(fallback_res, [])

    def test_replace_master_key(self) -> None:
        """uploading a new signing key should make the old signing key unavailable"""
        local_user = "@boris:" + self.hs.hostname
        keys1 = {
            "master_key": {
                # private key: 2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0
                "user_id": local_user,
                "usage": ["master"],
                "keys": {
                    "ed25519:nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk": "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk"
                },
            }
        }
        self.get_success(self.handler.upload_signing_keys_for_user(local_user, keys1))

        keys2 = {
            "master_key": {
                # private key: 4TL4AjRYwDVwD3pqQzcor+ez/euOB1/q78aTJ+czDNs
                "user_id": local_user,
                "usage": ["master"],
                "keys": {
                    "ed25519:Hq6gL+utB4ET+UvD5ci0kgAwsX6qP/zvf8v6OInU5iw": "Hq6gL+utB4ET+UvD5ci0kgAwsX6qP/zvf8v6OInU5iw"
                },
            }
        }
        self.get_success(self.handler.upload_signing_keys_for_user(local_user, keys2))

        devices = self.get_success(
            self.handler.query_devices(
                {"device_keys": {local_user: []}}, 0, local_user, "device123"
            )
        )
        self.assertDictEqual(devices["master_keys"], {local_user: keys2["master_key"]})

    def test_reupload_signatures(self) -> None:
        """re-uploading a signature should not fail"""
        local_user = "@boris:" + self.hs.hostname
        keys1 = {
            "master_key": {
                # private key: HvQBbU+hc2Zr+JP1sE0XwBe1pfZZEYtJNPJLZJtS+F8
                "user_id": local_user,
                "usage": ["master"],
                "keys": {
                    "ed25519:EmkqvokUn8p+vQAGZitOk4PWjp7Ukp3txV2TbMPEiBQ": "EmkqvokUn8p+vQAGZitOk4PWjp7Ukp3txV2TbMPEiBQ"
                },
            },
            "self_signing_key": {
                # private key: 2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0
                "user_id": local_user,
                "usage": ["self_signing"],
                "keys": {
                    "ed25519:nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk": "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk"
                },
            },
        }
        master_signing_key = key.decode_signing_key_base64(
            "ed25519",
            "EmkqvokUn8p+vQAGZitOk4PWjp7Ukp3txV2TbMPEiBQ",
            "HvQBbU+hc2Zr+JP1sE0XwBe1pfZZEYtJNPJLZJtS+F8",
        )
        sign.sign_json(keys1["self_signing_key"], local_user, master_signing_key)
        signing_key = key.decode_signing_key_base64(
            "ed25519",
            "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk",
            "2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0",
        )
        self.get_success(self.handler.upload_signing_keys_for_user(local_user, keys1))

        # upload two device keys, which will be signed later by the self-signing key
        device_key_1: JsonDict = {
            "user_id": local_user,
            "device_id": "abc",
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "keys": {
                "ed25519:abc": "base64+ed25519+key",
                "curve25519:abc": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:abc": "base64+signature"}},
        }
        device_key_2: JsonDict = {
            "user_id": local_user,
            "device_id": "def",
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "keys": {
                "ed25519:def": "base64+ed25519+key",
                "curve25519:def": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:def": "base64+signature"}},
        }

        self.get_success(
            self.handler.upload_keys_for_user(
                local_user, "abc", {"device_keys": device_key_1}
            )
        )
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user, "def", {"device_keys": device_key_2}
            )
        )

        # sign the first device key and upload it
        del device_key_1["signatures"]
        sign.sign_json(device_key_1, local_user, signing_key)
        self.get_success(
            self.handler.upload_signatures_for_device_keys(
                local_user, {local_user: {"abc": device_key_1}}
            )
        )

        # sign the second device key and upload both device keys.  The server
        # should ignore the first device key since it already has a valid
        # signature for it
        del device_key_2["signatures"]
        sign.sign_json(device_key_2, local_user, signing_key)
        self.get_success(
            self.handler.upload_signatures_for_device_keys(
                local_user, {local_user: {"abc": device_key_1, "def": device_key_2}}
            )
        )

        device_key_1["signatures"][local_user]["ed25519:abc"] = "base64+signature"
        device_key_2["signatures"][local_user]["ed25519:def"] = "base64+signature"
        devices = self.get_success(
            self.handler.query_devices(
                {"device_keys": {local_user: []}}, 0, local_user, "device123"
            )
        )
        del devices["device_keys"][local_user]["abc"]["unsigned"]
        del devices["device_keys"][local_user]["def"]["unsigned"]
        self.assertDictEqual(devices["device_keys"][local_user]["abc"], device_key_1)
        self.assertDictEqual(devices["device_keys"][local_user]["def"], device_key_2)

    def test_self_signing_key_doesnt_show_up_as_device(self) -> None:
        """signing keys should be hidden when fetching a user's devices"""
        local_user = "@boris:" + self.hs.hostname
        keys1 = {
            "master_key": {
                # private key: 2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0
                "user_id": local_user,
                "usage": ["master"],
                "keys": {
                    "ed25519:nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk": "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk"
                },
            }
        }
        self.get_success(self.handler.upload_signing_keys_for_user(local_user, keys1))

        device_handler = self.hs.get_device_handler()
        assert isinstance(device_handler, DeviceHandler)
        e = self.get_failure(
            device_handler.check_device_registered(
                user_id=local_user,
                device_id="nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk",
                initial_device_display_name="new display name",
            ),
            SynapseError,
        )
        res = e.value.code
        self.assertEqual(res, 400)

        query_res = self.get_success(
            self.handler.query_local_devices({local_user: None})
        )
        self.assertDictEqual(query_res, {local_user: {}})

    def test_upload_signatures(self) -> None:
        """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: JsonDict = {
            "user_id": local_user,
            "device_id": device_id,
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "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"
        )

        self.get_success(
            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: JsonDict = {
            "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,
        }
        self.get_success(
            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: JsonDict = {
            # private key: oyw2ZUx0O4GifbfFYM0nQvj9CL0b8B7cyN4FprtK8OI
            "user_id": other_user,
            "usage": ["master"],
            "keys": {"ed25519:" + other_master_pubkey: other_master_pubkey},
        }
        self.get_success(
            self.handler.upload_signing_keys_for_user(
                other_user, {"master_key": other_master_key}
            )
        )

        # test various signature failures (see below)
        ret = self.get_success(
            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-sha2",
                                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
                            ],
                            "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"], Codes.INVALID_SIGNATURE)
        self.assertEqual(
            user_failures[master_pubkey]["errcode"], Codes.INVALID_SIGNATURE
        )
        self.assertEqual(user_failures["unknown"]["errcode"], Codes.NOT_FOUND)

        other_user_failures = ret["failures"][other_user]
        self.assertEqual(other_user_failures["unknown"]["errcode"], Codes.NOT_FOUND)
        self.assertEqual(
            other_user_failures[other_master_pubkey]["errcode"], 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 = self.get_success(
            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 = self.get_success(
            self.handler.query_devices(
                {"device_keys": {local_user: [], other_user: []}},
                0,
                local_user,
                "device123",
            )
        )

        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],
        )

    def test_query_devices_remote_no_sync(self) -> None:
        """Tests that querying keys for a remote user that we don't share a room
        with returns the cross signing keys correctly.
        """

        remote_user_id = "@test:other"
        local_user_id = "@test:test"

        remote_master_key = "85T7JXPFBAySB/jwby4S3lBPTqY3+Zg53nYuGmu1ggY"
        remote_self_signing_key = "QeIiFEjluPBtI7WQdG365QKZcFs9kqmHir6RBD0//nQ"

        self.hs.get_federation_client().query_client_keys = mock.AsyncMock(  # type: ignore[method-assign]
            return_value={
                "device_keys": {remote_user_id: {}},
                "master_keys": {
                    remote_user_id: {
                        "user_id": remote_user_id,
                        "usage": ["master"],
                        "keys": {"ed25519:" + remote_master_key: remote_master_key},
                    },
                },
                "self_signing_keys": {
                    remote_user_id: {
                        "user_id": remote_user_id,
                        "usage": ["self_signing"],
                        "keys": {
                            "ed25519:"
                            + remote_self_signing_key: remote_self_signing_key
                        },
                    }
                },
            }
        )

        e2e_handler = self.hs.get_e2e_keys_handler()

        query_result = self.get_success(
            e2e_handler.query_devices(
                {
                    "device_keys": {remote_user_id: []},
                },
                timeout=10,
                from_user_id=local_user_id,
                from_device_id="some_device_id",
            )
        )

        self.assertEqual(query_result["failures"], {})
        self.assertEqual(
            query_result["master_keys"],
            {
                remote_user_id: {
                    "user_id": remote_user_id,
                    "usage": ["master"],
                    "keys": {"ed25519:" + remote_master_key: remote_master_key},
                },
            },
        )
        self.assertEqual(
            query_result["self_signing_keys"],
            {
                remote_user_id: {
                    "user_id": remote_user_id,
                    "usage": ["self_signing"],
                    "keys": {
                        "ed25519:" + remote_self_signing_key: remote_self_signing_key
                    },
                }
            },
        )

    def test_has_different_keys(self) -> None:
        """check that has_different_keys returns True when the keys provided are different to what
        is in the database."""
        local_user = "@boris:" + self.hs.hostname
        keys1 = {
            "master_key": {
                # private key: 2lonYOM6xYKdEsO+6KrC766xBcHnYnim1x/4LFGF8B0
                "user_id": local_user,
                "usage": ["master"],
                "keys": {
                    "ed25519:nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk": "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unI9kDYcHwk"
                },
            }
        }
        self.get_success(self.handler.upload_signing_keys_for_user(local_user, keys1))
        is_different = self.get_success(
            self.handler.has_different_keys(
                local_user,
                {
                    "master_key": keys1["master_key"],
                },
            )
        )
        self.assertEqual(is_different, False)
        # change the usage => different keys
        keys1["master_key"]["usage"] = ["develop"]
        is_different = self.get_success(
            self.handler.has_different_keys(
                local_user,
                {
                    "master_key": keys1["master_key"],
                },
            )
        )
        self.assertEqual(is_different, True)
        keys1["master_key"]["usage"] = ["master"]  # reset
        # change the key => different keys
        keys1["master_key"]["keys"] = {
            "ed25519:nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unIc0rncs": "nqOvzeuGWT/sRx3h7+MHoInYj3Uk2LD/unIc0rncs"
        }
        is_different = self.get_success(
            self.handler.has_different_keys(
                local_user,
                {
                    "master_key": keys1["master_key"],
                },
            )
        )
        self.assertEqual(is_different, True)

    def test_query_devices_remote_sync(self) -> None:
        """Tests that querying keys for a remote user that we share a room with,
        but haven't yet fetched the keys for, returns the cross signing keys
        correctly.
        """

        remote_user_id = "@test:other"
        local_user_id = "@test:test"

        # Pretend we're sharing a room with the user we're querying. If not,
        # `_query_devices_for_destination` will return early.
        self.store.get_rooms_for_user = mock.AsyncMock(return_value={"some_room_id"})

        remote_master_key = "85T7JXPFBAySB/jwby4S3lBPTqY3+Zg53nYuGmu1ggY"
        remote_self_signing_key = "QeIiFEjluPBtI7WQdG365QKZcFs9kqmHir6RBD0//nQ"

        self.hs.get_federation_client().query_user_devices = mock.AsyncMock(  # type: ignore[method-assign]
            return_value={
                "user_id": remote_user_id,
                "stream_id": 1,
                "devices": [],
                "master_key": {
                    "user_id": remote_user_id,
                    "usage": ["master"],
                    "keys": {"ed25519:" + remote_master_key: remote_master_key},
                },
                "self_signing_key": {
                    "user_id": remote_user_id,
                    "usage": ["self_signing"],
                    "keys": {
                        "ed25519:" + remote_self_signing_key: remote_self_signing_key
                    },
                },
            }
        )

        e2e_handler = self.hs.get_e2e_keys_handler()

        query_result = self.get_success(
            e2e_handler.query_devices(
                {
                    "device_keys": {remote_user_id: []},
                },
                timeout=10,
                from_user_id=local_user_id,
                from_device_id="some_device_id",
            )
        )

        self.assertEqual(query_result["failures"], {})
        self.assertEqual(
            query_result["master_keys"],
            {
                remote_user_id: {
                    "user_id": remote_user_id,
                    "usage": ["master"],
                    "keys": {"ed25519:" + remote_master_key: remote_master_key},
                }
            },
        )
        self.assertEqual(
            query_result["self_signing_keys"],
            {
                remote_user_id: {
                    "user_id": remote_user_id,
                    "usage": ["self_signing"],
                    "keys": {
                        "ed25519:" + remote_self_signing_key: remote_self_signing_key
                    },
                }
            },
        )

    def test_query_devices_remote_down(self) -> None:
        """Tests that querying keys for a remote user on an unreachable server returns
        results in the "failures" property
        """

        remote_user_id = "@test:other"
        local_user_id = "@test:test"

        # The backoff code treats time zero as special
        self.reactor.advance(5)

        self.hs.get_federation_http_client().agent.request = mock.AsyncMock(  # type: ignore[method-assign]
            side_effect=Exception("boop")
        )

        e2e_handler = self.hs.get_e2e_keys_handler()

        query_result = self.get_success(
            e2e_handler.query_devices(
                {
                    "device_keys": {remote_user_id: []},
                },
                timeout=10,
                from_user_id=local_user_id,
                from_device_id="some_device_id",
            )
        )

        self.assertEqual(
            query_result["failures"],
            {
                "other": {
                    "message": "Failed to send request: Exception: boop",
                    "status": 503,
                }
            },
        )

        # Do it again: we should hit the backoff
        query_result = self.get_success(
            e2e_handler.query_devices(
                {
                    "device_keys": {remote_user_id: []},
                },
                timeout=10,
                from_user_id=local_user_id,
                from_device_id="some_device_id",
            )
        )

        self.assertEqual(
            query_result["failures"],
            {"other": {"message": "Not ready for retry", "status": 503}},
        )

    @parameterized.expand(
        [
            # The remote homeserver's response indicates that this user has 0/1/2 devices.
            ([],),
            (["device_1"],),
            (["device_1", "device_2"],),
        ]
    )
    def test_query_all_devices_caches_result(self, device_ids: Iterable[str]) -> None:
        """Test that requests for all of a remote user's devices are cached.

        We do this by asserting that only one call over federation was made, and that
        the two queries to the local homeserver produce the same response.
        """
        local_user_id = "@test:test"
        remote_user_id = "@test:other"
        request_body: JsonDict = {"device_keys": {remote_user_id: []}}

        response_devices = [
            {
                "device_id": device_id,
                "keys": {
                    "algorithms": ["dummy"],
                    "device_id": device_id,
                    "keys": {f"dummy:{device_id}": "dummy"},
                    "signatures": {device_id: {f"dummy:{device_id}": "dummy"}},
                    "unsigned": {},
                    "user_id": "@test:other",
                },
            }
            for device_id in device_ids
        ]

        response_body = {
            "devices": response_devices,
            "user_id": remote_user_id,
            "stream_id": 12345,  # an integer, according to the spec
        }

        e2e_handler = self.hs.get_e2e_keys_handler()

        # Pretend we're sharing a room with the user we're querying. If not,
        # `_query_devices_for_destination` will return early.
        mock_get_rooms = mock.patch.object(
            self.store,
            "get_rooms_for_user",
            new_callable=mock.AsyncMock,
            return_value=["some_room_id"],
        )
        mock_get_users = mock.patch.object(
            self.store,
            "get_users_server_still_shares_room_with",
            new_callable=mock.AsyncMock,
            return_value={remote_user_id},
        )
        mock_request = mock.patch.object(
            self.hs.get_federation_client(),
            "query_user_devices",
            new_callable=mock.AsyncMock,
            return_value=response_body,
        )

        with mock_get_rooms, mock_get_users, mock_request as mocked_federation_request:
            # Make the first query and sanity check it succeeds.
            response_1 = self.get_success(
                e2e_handler.query_devices(
                    request_body,
                    timeout=10,
                    from_user_id=local_user_id,
                    from_device_id="some_device_id",
                )
            )
            self.assertEqual(response_1["failures"], {})

            # We should have made a federation request to do so.
            mocked_federation_request.assert_called_once()

            # Reset the mock so we can prove we don't make a second federation request.
            mocked_federation_request.reset_mock()

            # Repeat the query.
            response_2 = self.get_success(
                e2e_handler.query_devices(
                    request_body,
                    timeout=10,
                    from_user_id=local_user_id,
                    from_device_id="some_device_id",
                )
            )
            self.assertEqual(response_2["failures"], {})

            # We should not have made a second federation request.
            mocked_federation_request.assert_not_called()

            # The two requests to the local homeserver should be identical.
            self.assertEqual(response_1, response_2)

    @override_config({"experimental_features": {"msc3983_appservice_otk_claims": True}})
    def test_query_appservice(self) -> None:
        local_user = "@boris:" + self.hs.hostname
        device_id_1 = "xyz"
        fallback_key = {"alg1:k1": "fallback_key1"}
        device_id_2 = "abc"
        otk = {"alg1:k2": "key2"}

        # Inject an appservice interested in this user.
        appservice = ApplicationService(
            token="i_am_an_app_service",
            id="1234",
            namespaces={"users": [{"regex": r"@boris:.+", "exclusive": True}]},
            # Note: this user does not have to match the regex above
            sender="@as_main:test",
        )
        self.hs.get_datastores().main.services_cache = [appservice]
        self.hs.get_datastores().main.exclusive_user_regex = _make_exclusive_regex(
            [appservice]
        )

        # Setup a response, but only for device 2.
        self.appservice_api.claim_client_keys.return_value = (
            {local_user: {device_id_2: otk}},
            [(local_user, device_id_1, "alg1", 1)],
        )

        # we shouldn't have any unused fallback keys yet
        res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(res, [])

        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id_1,
                {"fallback_keys": fallback_key},
            )
        )

        # we should now have an unused alg1 key
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # claiming an OTK when no OTKs are available should ask the appservice, then
        # query the fallback keys.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id_1: {"alg1": 1}, device_id_2: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=False,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {
                    local_user: {device_id_1: fallback_key, device_id_2: otk}
                },
            },
        )

    @override_config({"experimental_features": {"msc3983_appservice_otk_claims": True}})
    def test_query_appservice_with_fallback(self) -> None:
        local_user = "@boris:" + self.hs.hostname
        device_id_1 = "xyz"
        fallback_key = {"alg1:k1": {"desc": "fallback_key1", "fallback": True}}
        otk = {"alg1:k2": {"desc": "key2"}}
        as_fallback_key = {"alg1:k3": {"desc": "fallback_key3", "fallback": True}}
        as_otk = {"alg1:k4": {"desc": "key4"}}

        # Inject an appservice interested in this user.
        appservice = ApplicationService(
            token="i_am_an_app_service",
            id="1234",
            namespaces={"users": [{"regex": r"@boris:.+", "exclusive": True}]},
            # Note: this user does not have to match the regex above
            sender="@as_main:test",
        )
        self.hs.get_datastores().main.services_cache = [appservice]
        self.hs.get_datastores().main.exclusive_user_regex = _make_exclusive_regex(
            [appservice]
        )

        # Setup a response.
        response: Dict[str, Dict[str, Dict[str, JsonDict]]] = {
            local_user: {device_id_1: {**as_otk, **as_fallback_key}}
        }
        self.appservice_api.claim_client_keys.return_value = (response, [])

        # Claim OTKs, which will ask the appservice and do nothing else.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id_1: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {
                    local_user: {device_id_1: {**as_otk, **as_fallback_key}}
                },
            },
        )

        # Now upload a fallback key.
        res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(res, [])

        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id_1,
                {"fallback_keys": fallback_key},
            )
        )

        # we should now have an unused alg1 key
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # The appservice will return only the OTK.
        self.appservice_api.claim_client_keys.return_value = (
            {local_user: {device_id_1: as_otk}},
            [],
        )

        # Claim OTKs, which should return the OTK from the appservice and the
        # uploaded fallback key.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id_1: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {
                    local_user: {device_id_1: {**as_otk, **fallback_key}}
                },
            },
        )

        # But the fallback key should not be marked as used.
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # Now upload a OTK.
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user,
                device_id_1,
                {"one_time_keys": otk},
            )
        )

        # Claim OTKs, which will return information only from the database.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id_1: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {local_user: {device_id_1: {**otk, **fallback_key}}},
            },
        )

        # But the fallback key should not be marked as used.
        fallback_res = self.get_success(
            self.store.get_e2e_unused_fallback_key_types(local_user, device_id_1)
        )
        self.assertEqual(fallback_res, ["alg1"])

        # Finally, return only the fallback key from the appservice.
        self.appservice_api.claim_client_keys.return_value = (
            {local_user: {device_id_1: as_fallback_key}},
            [],
        )

        # Claim OTKs, which will return only the fallback key from the database.
        claim_res = self.get_success(
            self.handler.claim_one_time_keys(
                {local_user: {device_id_1: {"alg1": 1}}},
                self.requester,
                timeout=None,
                always_include_fallback_keys=True,
            )
        )
        self.assertEqual(
            claim_res,
            {
                "failures": {},
                "one_time_keys": {local_user: {device_id_1: as_fallback_key}},
            },
        )

    @override_config({"experimental_features": {"msc3984_appservice_key_query": True}})
    def test_query_local_devices_appservice(self) -> None:
        """Test that querying of appservices for keys overrides responses from the database."""
        local_user = "@boris:" + self.hs.hostname
        device_1 = "abc"
        device_2 = "def"
        device_3 = "ghi"

        # There are 3 devices:
        #
        # 1. One which is uploaded to the homeserver.
        # 2. One which is uploaded to the homeserver, but a newer copy is returned
        #     by the appservice.
        # 3. One which is only returned by the appservice.
        device_key_1: JsonDict = {
            "user_id": local_user,
            "device_id": device_1,
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "keys": {
                "ed25519:abc": "base64+ed25519+key",
                "curve25519:abc": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:abc": "base64+signature"}},
        }
        device_key_2a: JsonDict = {
            "user_id": local_user,
            "device_id": device_2,
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "keys": {
                "ed25519:def": "base64+ed25519+key",
                "curve25519:def": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:def": "base64+signature"}},
        }

        device_key_2b: JsonDict = {
            "user_id": local_user,
            "device_id": device_2,
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            # The device ID is the same (above), but the keys are different.
            "keys": {
                "ed25519:xyz": "base64+ed25519+key",
                "curve25519:xyz": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:xyz": "base64+signature"}},
        }
        device_key_3: JsonDict = {
            "user_id": local_user,
            "device_id": device_3,
            "algorithms": [
                "m.olm.curve25519-aes-sha2",
                RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2,
            ],
            "keys": {
                "ed25519:jkl": "base64+ed25519+key",
                "curve25519:jkl": "base64+curve25519+key",
            },
            "signatures": {local_user: {"ed25519:jkl": "base64+signature"}},
        }

        # Upload keys for devices 1 & 2a.
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_1, {"device_keys": device_key_1}
            )
        )
        self.get_success(
            self.handler.upload_keys_for_user(
                local_user, device_2, {"device_keys": device_key_2a}
            )
        )

        # Inject an appservice interested in this user.
        appservice = ApplicationService(
            token="i_am_an_app_service",
            id="1234",
            namespaces={"users": [{"regex": r"@boris:.+", "exclusive": True}]},
            # Note: this user does not have to match the regex above
            sender="@as_main:test",
        )
        self.hs.get_datastores().main.services_cache = [appservice]
        self.hs.get_datastores().main.exclusive_user_regex = _make_exclusive_regex(
            [appservice]
        )

        # Setup a response.
        self.appservice_api.query_keys.return_value = {
            "device_keys": {
                local_user: {device_2: device_key_2b, device_3: device_key_3}
            }
        }

        # Request all devices.
        res = self.get_success(self.handler.query_local_devices({local_user: None}))
        self.assertIn(local_user, res)
        for res_key in res[local_user].values():
            res_key.pop("unsigned", None)
        self.assertDictEqual(
            res,
            {
                local_user: {
                    device_1: device_key_1,
                    device_2: device_key_2b,
                    device_3: device_key_3,
                }
            },
        )

    def test_check_cross_signing_setup(self) -> None:
        # First check what happens with no master key.
        alice = "@alice:test"
        exists, replaceable_without_uia = self.get_success(
            self.handler.check_cross_signing_setup(alice)
        )
        self.assertIs(exists, False)
        self.assertIs(replaceable_without_uia, False)

        # Upload a master key but don't specify a replacement timestamp.
        dummy_key = {"keys": {"a": "b"}}
        self.get_success(
            self.store.set_e2e_cross_signing_key("@alice:test", "master", dummy_key)
        )

        # Should now find the key exists.
        exists, replaceable_without_uia = self.get_success(
            self.handler.check_cross_signing_setup(alice)
        )
        self.assertIs(exists, True)
        self.assertIs(replaceable_without_uia, False)

        # Set an expiry timestamp in the future.
        self.get_success(
            self.store.allow_master_cross_signing_key_replacement_without_uia(
                alice,
                1000,
            )
        )

        # Should now be allowed to replace the key without UIA.
        exists, replaceable_without_uia = self.get_success(
            self.handler.check_cross_signing_setup(alice)
        )
        self.assertIs(exists, True)
        self.assertIs(replaceable_without_uia, True)

        # Wait 2 seconds, so that the timestamp is in the past.
        self.reactor.advance(2.0)

        # Should no longer be allowed to replace the key without UIA.
        exists, replaceable_without_uia = self.get_success(
            self.handler.check_cross_signing_setup(alice)
        )
        self.assertIs(exists, True)
        self.assertIs(replaceable_without_uia, False)