Software /
code /
prosody
File
plugins/mod_tombstones.lua @ 12446:e54b8a5e35ad 0.12
util.random: Test whether util.crand works before using it (fix #1734)
util.crand can be configured at compile time to use the Linux
getrandom() system call, available from Linux 3.17, but it is still
possible to load it with an older kernel lacking that system call, where
attempting to use it throws an ENOSYS error.
By testing for this on load we can fall back to /dev/urandom in this
case.
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sat, 02 Apr 2022 16:33:27 +0200 |
parent | 12438:a698f65df453 |
child | 12977:74b9e05af71e |
line wrap: on
line source
-- TODO warn when trying to create an user before the tombstone expires -- e.g. via telnet or other admin interface local datetime = require "util.datetime"; local errors = require "util.error"; local jid_node = require"util.jid".node; local st = require "util.stanza"; -- Using a map store as key-value store so that removal of all user data -- does not also remove the tombstone, which would defeat the point local graveyard = module:open_store(nil, "map"); local graveyard_cache = require "util.cache".new(module:get_option_number("tombstone_cache_size", 1024)); local ttl = module:get_option_number("user_tombstone_expiry", nil); -- Keep tombstones forever by default -- -- Rationale: -- There is no way to be completely sure when remote services have -- forgotten and revoked all memberships. -- TODO If the user left a JID they moved to, return a gone+redirect error -- TODO Attempt to deregister from MUCs based on bookmarks -- TODO Unsubscribe from pubsub services if a notification is received module:hook_global("user-deleted", function(event) if event.host == module.host then local ok, err = graveyard:set(nil, event.username, os.time()); if not ok then module:log("error", "Could store tombstone for %s: %s", event.username, err); end end end); -- Public API function has_tombstone(username) local tombstone; -- Check cache local cached_result = graveyard_cache:get(username); if cached_result == false then -- We cached that there is no tombstone for this user return false; elseif cached_result then tombstone = cached_result; else local stored_result, err = graveyard:get(nil, username); if not stored_result and not err then -- Cache that there is no tombstone for this user graveyard_cache:set(username, false); return false; elseif err then -- Failed to check tombstone status return nil, err; end -- We have a tombstone stored, so let's continue with that tombstone = stored_result; end -- Check expiry if ttl and tombstone + ttl < os.time() then module:log("debug", "Tombstone for %s created at %s has expired", username, datetime.datetime(tombstone)); graveyard:set(nil, username, nil); graveyard_cache:set(username, nil); -- clear cache entry (if any) return nil; end -- Cache for the future graveyard_cache:set(username, tombstone); return tombstone; end module:hook("user-registering", function(event) local tombstone, err = has_tombstone(event.username); if err then event.allowed, event.error = errors.coerce(false, err); return true; elseif not tombstone then -- Feel free return; end module:log("debug", "Tombstone for %s created at %s", event.username, datetime.datetime(tombstone)); event.allowed = false; return true; end); module:hook("presence/bare", function(event) local origin, presence = event.origin, event.stanza; local local_username = jid_node(presence.attr.to); if not local_username then return; end -- We want to undo any left-over presence subscriptions and notify the former -- contact that they're gone. -- -- FIXME This leaks that the user once existed. Hard to avoid without keeping -- the contact list in some form, which we don't want to do for privacy -- reasons. Bloom filter perhaps? local pres_type = presence.attr.type; local is_probe = pres_type == "probe"; local is_normal = pres_type == nil or pres_type == "unavailable"; if is_probe and has_tombstone(local_username) then origin.send(st.error_reply(presence, "cancel", "gone", "User deleted")); origin.send(st.presence({ type = "unsubscribed"; to = presence.attr.from; from = presence.attr.to })); return true; elseif is_normal and has_tombstone(local_username) then origin.send(st.error_reply(presence, "cancel", "gone", "User deleted")); origin.send(st.presence({ type = "unsubscribe"; to = presence.attr.from; from = presence.attr.to })); return true; end end, 1);