view mod_inject_ecaps2/mod_inject_ecaps2.lua @ 4976:75b6e5df65f9

various: Improve error reporting if missing file server module on 0.12 If there is some error loading net.http.files then it would be swallowed by the pcall and then it would proceed to trying mod_http_files, which might cause unexpected behavior on 0.12 Ref #1765
author Kim Alvefur <zash@zash.se>
date Mon, 18 Jul 2022 22:47:54 +0200
parents ce946d9d982e
children
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module:depends("cache_c2s_caps");

local st = require "util.stanza";
local hashes = require "util.hashes";
local base64 = require "util.encodings".base64;
local t_insert, t_sort, t_concat = table.insert, table.sort, table.concat;

local algorithms = module:get_option_set("ecaps2_hashes", { "sha-256", "sha-512" });

-- TODO: Add all of the other hashes supported.
local algorithm_map = {
	["sha-256"] = hashes.sha256;
	["sha-512"] = hashes.sha512;
};

-- TODO: move that to util.caps maybe.
local function calculate_hash(disco_info)
	local identities, features, extensions = {}, {}, {};
	for _, tag in ipairs(disco_info) do
		if tag.name == "identity" then
			t_insert(identities, ((tag.attr.category or "").."\31"..
			                      (tag.attr.type or "").."\31"..
					      (tag.attr["xml:lang"] or "").."\31"..
					      (tag.attr.name or "").."\31\30"));
		elseif tag.name == "feature" then
			t_insert(features, (tag.attr.var or "").."\31");
		elseif tag.name == "x" and tag.attr.xmlns == "jabber:x:data" then
			local form = {};
			for _, field in ipairs(tag.tags) do
				if field.name == "field" and field.attr.xmlns == "jabber:x:data" and field.attr.var then
					local values = {};
					for _, value in ipairs(field.tags) do
						if value.name == "value" and value.attr.xmlns == "jabber:x:data" then
							value = #value.tags == 0 and value:get_text();
							if value then t_insert(values, value.."\31"); end
						end
					end
					t_sort(values);
					if #values > 0 then
						t_insert(form, field.attr.var.."\31"..t_concat(values, "\31").."\31\30");
					else
						t_insert(form, field.attr.var.."\31\30");
					end
				end
			end
			t_sort(form);
			form = t_concat(form, "\29").."\29";
			t_insert(extensions, form);
		else
			return nil, "Unknown element in disco#info";
		end
	end
	t_sort(identities);
	t_sort(features);
	t_sort(extensions);
	if #identities > 0 then identities = t_concat(identities, "\28").."\28"; else identities = "\28"; end
	if #features > 0 then features = t_concat(features).."\28"; else features = "\28"; end
	if #extensions > 0 then extensions = t_concat(extensions, "\28").."\28"; else extensions = "\28"; end
	return features..identities..extensions;
end

local function caps_handler(event)
	local origin = event.origin;

	if origin.presence == nil or origin.presence:get_child("c", "urn:xmpp:caps") then
		return;
	end

	local disco_info = origin.caps_cache;
	if disco_info == nil then
		return;
	end

	local extension_string, err = calculate_hash(disco_info);
	if extension_string == nil then
		module:log("warn", "Failed to calculate ecaps2 hash: %s", err)
		return;
	end

	local ecaps2 = st.stanza("c", { xmlns = "urn:xmpp:caps" });
	for algo in algorithms do
		local func = algorithm_map[algo];
		if func ~= nil then
			local hash = base64.encode(func(extension_string));
			ecaps2:tag("hash", { xmlns = "urn:xmpp:hashes:2"; algo = algo })
			      :text(hash)
			      :up();
		end
	end

	module:log("debug", "Injected ecaps2 element in presence");
	origin.presence:add_child(ecaps2);
end

module:hook("c2s-capabilities-changed", caps_handler);