File

mod_http_pep_avatar/mod_http_pep_avatar.lua @ 5193:2bb29ece216b

mod_http_oauth2: Implement stateless dynamic client registration Replaces previous explicit registration that required either the additional module mod_adhoc_oauth2_client or manually editing the database. That method was enough to have something to test with, but would not probably not scale easily. Dynamic client registration allows creating clients on the fly, which may be even easier in theory. In order to not allow basically unauthenticated writes to the database, we implement a stateless model here. per_host_key := HMAC(config -> oauth2_registration_key, hostname) client_id := JWT { client metadata } signed with per_host_key client_secret := HMAC(per_host_key, client_id) This should ensure everything we need to know is part of the client_id, allowing redirects etc to be validated, and the client_secret can be validated with only the client_id and the per_host_key. A nonce injected into the client_id JWT should ensure nobody can submit the same client metadata and retrieve the same client_secret
author Kim Alvefur <zash@zash.se>
date Fri, 03 Mar 2023 21:14:19 +0100
parent 4038:02d238799537
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-- HTTP Access to PEP Avatar
-- By Kim Alvefur <zash@zash.se>

local mod_pep = module:depends"pep";

local um = require "core.usermanager";
local nodeprep = require "util.encodings".stringprep.nodeprep;
local base64_decode = require "util.encodings".base64.decode;
local urlencode = require "util.http".urlencode;

module:depends("http")
module:provides("http", {
	route = {
		["GET /*"] = function (event, path)
			if path == "" then
				return [[<h1>Hello from mod_http_pep_avatar</h1><p>This module provides access to public avatars of local users.</p>]];
			end;

			local request, response = event.request, event.response;
			local actor = request.ip;

			local user, item_id = path:match("^([^/]+)/(%x+)$");
			if not user then user = path; end
			local prepped = nodeprep(user);
			if not prepped then return 400; end
			if prepped ~= user then
				response.headers.location = module:http_url() .. "/" .. urlencode(prepped);
				return 302;
			end
			if not um.user_exists(user, module.host) then
				return 404;
			end

			local pep_service = mod_pep.get_pep_service(user);

			local ok, avatar_hash, avatar_meta = pep_service:get_last_item("urn:xmpp:avatar:metadata", actor);

			if not ok or not avatar_hash then
				return 404;
			end

			if (item_id or avatar_hash) == request.headers.if_none_match then
				return 304;
			end

			local data_ok, avatar_data = pep_service:get_items("urn:xmpp:avatar:data", actor, item_id or avatar_hash);
			if not data_ok or type(avatar_data) ~= "table" or not avatar_data[item_id or avatar_hash] then
				return 404;
			end

			local info = avatar_meta.tags[1]:get_child("info");
			if item_id and info.attr.id ~= item_id then
				info = nil;
				for altinfo in avatar_meta.tags[1]:childtags("info") do
					if altinfo.attr.id == item_id then
						info = altinfo;
					end
				end
			end

			if not info then
				return 404;
			end

			response.headers.etag = item_id or avatar_hash;

			response.headers.content_type = info and info.attr.type or "application/octet-stream";

			local data = avatar_data[item_id or avatar_hash];
			return base64_decode(data.tags[1]:get_text());
		end;
	}
});