Delete stale non-e2e devices for users, take 2 (#14595)

This should help reduce the number of devices e.g. simple bots the repeatedly login rack up.

We only delete non-e2e devices as they should be safe to delete, whereas if we delete e2e devices for a user we may accidentally break their ability to receive e2e keys for a message.
This commit is contained in:
Erik Johnston 2022-12-09 09:37:07 +00:00 committed by GitHub
parent a58b550eac
commit c2de2ca630
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5 changed files with 113 additions and 4 deletions

1
changelog.d/14595.misc Normal file
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@ -0,0 +1 @@
Prune user's old devices on login if they have too many.

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@ -52,6 +52,7 @@ from synapse.util import stringutils
from synapse.util.async_helpers import Linearizer
from synapse.util.caches.expiringcache import ExpiringCache
from synapse.util.cancellation import cancellable
from synapse.util.iterutils import batch_iter
from synapse.util.metrics import measure_func
from synapse.util.retryutils import NotRetryingDestination
@ -421,6 +422,9 @@ class DeviceHandler(DeviceWorkerHandler):
self._check_device_name_length(initial_device_display_name)
# Prune the user's device list if they already have a lot of devices.
await self._prune_too_many_devices(user_id)
if device_id is not None:
new_device = await self.store.store_device(
user_id=user_id,
@ -452,6 +456,31 @@ class DeviceHandler(DeviceWorkerHandler):
raise errors.StoreError(500, "Couldn't generate a device ID.")
async def _prune_too_many_devices(self, user_id: str) -> None:
"""Delete any excess old devices this user may have."""
device_ids = await self.store.check_too_many_devices_for_user(user_id)
if not device_ids:
return
# We don't want to block and try and delete tonnes of devices at once,
# so we cap the number of devices we delete synchronously.
first_batch, remaining_device_ids = device_ids[:10], device_ids[10:]
await self.delete_devices(user_id, first_batch)
if not remaining_device_ids:
return
# Now spawn a background loop that deletes the rest.
async def _prune_too_many_devices_loop() -> None:
for batch in batch_iter(remaining_device_ids, 10):
await self.delete_devices(user_id, batch)
await self.clock.sleep(1)
run_as_background_process(
"_prune_too_many_devices_loop", _prune_too_many_devices_loop
)
async def _delete_stale_devices(self) -> None:
"""Background task that deletes devices which haven't been accessed for more than
a configured time period.
@ -481,7 +510,7 @@ class DeviceHandler(DeviceWorkerHandler):
device_ids = [d for d in device_ids if d != except_device_id]
await self.delete_devices(user_id, device_ids)
async def delete_devices(self, user_id: str, device_ids: List[str]) -> None:
async def delete_devices(self, user_id: str, device_ids: Collection[str]) -> None:
"""Delete several devices
Args:

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@ -1569,6 +1569,72 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
return rows
async def check_too_many_devices_for_user(self, user_id: str) -> List[str]:
"""Check if the user has a lot of devices, and if so return the set of
devices we can prune.
This does *not* return hidden devices or devices with E2E keys.
"""
num_devices = await self.db_pool.simple_select_one_onecol(
table="devices",
keyvalues={"user_id": user_id, "hidden": False},
retcol="COALESCE(COUNT(*), 0)",
desc="count_devices",
)
# We let users have up to ten devices without pruning.
if num_devices <= 10:
return []
# We prune everything older than N days.
max_last_seen = self._clock.time_msec() - 14 * 24 * 60 * 60 * 1000
if num_devices > 50:
# If the user has more than 50 devices, then we chose a last seen
# that ensures we keep at most 50 devices.
sql = """
SELECT last_seen FROM devices
LEFT JOIN e2e_device_keys_json USING (user_id, device_id)
WHERE
user_id = ?
AND NOT hidden
AND last_seen IS NOT NULL
AND key_json IS NULL
ORDER BY last_seen DESC
LIMIT 1
OFFSET 50
"""
rows = await self.db_pool.execute(
"check_too_many_devices_for_user_last_seen", None, sql, (user_id,)
)
if rows:
max_last_seen = max(rows[0][0], max_last_seen)
# Now fetch the devices to delete.
sql = """
SELECT DISTINCT device_id FROM devices
LEFT JOIN e2e_device_keys_json USING (user_id, device_id)
WHERE
user_id = ?
AND NOT hidden
AND last_seen < ?
AND key_json IS NULL
ORDER BY last_seen
"""
def check_too_many_devices_for_user_txn(
txn: LoggingTransaction,
) -> List[str]:
txn.execute(sql, (user_id, max_last_seen))
return [device_id for device_id, in txn]
return await self.db_pool.runInteraction(
"check_too_many_devices_for_user",
check_too_many_devices_for_user_txn,
)
class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
# Because we have write access, this will be a StreamIdGenerator
@ -1627,6 +1693,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
values={},
insertion_values={
"display_name": initial_device_display_name,
"last_seen": self._clock.time_msec(),
"hidden": False,
},
desc="store_device",
@ -1672,7 +1739,15 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
)
raise StoreError(500, "Problem storing device.")
async def delete_devices(self, user_id: str, device_ids: List[str]) -> None:
@cached(max_entries=0)
async def delete_device(self, user_id: str, device_id: str) -> None:
raise NotImplementedError()
# Note: sometimes deleting rows out of `device_inbox` can take a long time,
# so we use a cache so that we deduplicate in flight requests to delete
# devices.
@cachedList(cached_method_name="delete_device", list_name="device_ids")
async def delete_devices(self, user_id: str, device_ids: Collection[str]) -> dict:
"""Deletes several devices.
Args:
@ -1709,6 +1784,8 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
for device_id in device_ids:
self.device_id_exists_cache.invalidate((user_id, device_id))
return {}
async def update_device(
self, user_id: str, device_id: str, new_display_name: Optional[str] = None
) -> None:

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@ -115,7 +115,7 @@ class DeviceTestCase(unittest.HomeserverTestCase):
"device_id": "xyz",
"display_name": "display 0",
"last_seen_ip": None,
"last_seen_ts": None,
"last_seen_ts": 1000000,
},
device_map["xyz"],
)

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@ -169,6 +169,8 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
)
)
last_seen = self.clock.time_msec()
if after_persisting:
# Trigger the storage loop
self.reactor.advance(10)
@ -189,7 +191,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
"device_id": device_id,
"ip": None,
"user_agent": None,
"last_seen": None,
"last_seen": last_seen,
},
],
)