view mod_readonly/mod_readonly.lua @ 4651:8231774f5bfd

mod_cloud_notify_encrypted: Ensure body substring remains valid UTF-8 The `body:sub()` call risks splitting the string in the middle of a multi-byte UTF-8 sequence. This should have been caught by util.stanza validation, but that would have caused some havoc, at the very least causing the notification to not be sent. There have been no reports of this happening. Likely because this module isn't widely deployed among users with languages that use many longer UTF-8 sequences. The util.encodings.utf8.valid() function is O(n) where only the last sequence really needs to be checked, but it's in C and expected to be fast.
author Kim Alvefur <zash@zash.se>
date Sun, 22 Aug 2021 13:22:59 +0200
parents 7776c9dc5f37
children
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local st = require "util.stanza";

local stores = module:get_option("readonly_stores", {
	vcard = { "vcard-temp", "vCard" };
});

local namespaces = {};
for name, namespace in pairs(stores) do
	namespaces[table.concat(namespace, ":")] = name;
end

local function prevent_write(event)
	local stanza = event.stanza;
	local xmlns_and_tag = stanza.tags[1].attr.xmlns..":"..stanza.tags[1].name;
	local store_name = namespaces[xmlns_and_tag];
	if store_name then
		module:log("warn", "Preventing modification of %s store by %s", store_name, stanza.attr.from);
		event.origin.send(st.error_reply(stanza, "cancel", "not-allowed", store_name.." data is read-only"));
		return true; -- Block stanza
	end
end

for namespace in pairs(namespaces) do
	module:hook("iq-set/bare/"..namespace, prevent_write, 200);
end