mod_auth_oauth_external: Expect XEP-0106 escaped username in PLAIN
This allows entering an email address as username in some clients by
escaping the @ as \40, enabling authentication against Mastodon
local http = require "net.http";
local async = require "util.async";
local jid = require "util.jid";
local json = require "util.json";
local sasl = require "util.sasl";
local issuer_identity = module:get_option_string("oauth_external_issuer");
local oidc_discovery_url = module:get_option_string("oauth_external_discovery_url",
issuer_identity and issuer_identity .. "/.well-known/oauth-authorization-server" or nil);
local validation_endpoint = module:get_option_string("oauth_external_validation_endpoint");
local token_endpoint = module:get_option_string("oauth_external_token_endpoint");
local username_field = module:get_option_string("oauth_external_username_field", "preferred_username");
local allow_plain = module:get_option_boolean("oauth_external_resource_owner_password", true);
-- XXX Hold up, does whatever done here even need any of these things? Are we
-- the OAuth client? Is the XMPP client the OAuth client? What are we???
local client_id = module:get_option_string("oauth_external_client_id");
local client_secret = module:get_option_string("oauth_external_client_secret");
local scope = module:get_option_string("oauth_external_scope", "openid");
--[[ More or less required endpoints
digraph "oauth endpoints" {
issuer -> discovery -> { registration validation }
registration -> { client_id client_secret }
{ client_id client_secret validation } -> required
}
--]]
local host = module.host;
local provider = {};
function provider.get_sasl_handler()
local profile = {};
profile.http_client = http.default; -- TODO configurable
local extra = { oidc_discovery_url = oidc_discovery_url };
if token_endpoint and allow_plain then
local map_username = function (username, _realm) return username; end; --jid.join; -- TODO configurable
function profile:plain_test(username, password, realm)
username = jid.unescape(username); -- COMPAT Mastodon
local tok, err = async.wait_for(self.profile.http_client:request(token_endpoint, {
headers = { ["Content-Type"] = "application/x-www-form-urlencoded; charset=utf-8"; ["Accept"] = "application/json" };
body = http.formencode({
grant_type = "password";
client_id = client_id;
client_secret = client_secret;
username = map_username(username, realm);
password = password;
scope = scope;
});
}))
if err or not (tok.code >= 200 and tok.code < 300) then
return false, nil;
end
local token_resp = json.decode(tok.body);
if not token_resp or string.lower(token_resp.token_type or "") ~= "bearer" then
return false, nil;
end
if not validation_endpoint then
-- We're not going to get more info, only the username
self.username = jid.escape(username);
self.token_info = token_resp;
return true, true;
end
local ret, err = async.wait_for(self.profile.http_client:request(validation_endpoint,
{ headers = { ["Authorization"] = "Bearer " .. token_resp.access_token; ["Accept"] = "application/json" } }));
if err then
return false, nil;
end
if not (ret.code >= 200 and ret.code < 300) then
return false, nil;
end
local response = json.decode(ret.body);
if type(response) ~= "table" or (response[username_field]) ~= username then
return false, nil, nil;
end
if response.jid then
self.username, self.realm, self.resource = jid.prepped_split(response.jid, true);
end
self.role = response.role;
self.token_info = response;
return true, true;
end
end
if validation_endpoint then
function profile:oauthbearer(token)
if token == "" then
return false, nil, extra;
end
local ret, err = async.wait_for(self.profile.http_client:request(validation_endpoint, {
headers = { ["Authorization"] = "Bearer " .. token; ["Accept"] = "application/json" };
}));
if err then
return false, nil, extra;
end
local response = ret and json.decode(ret.body);
if not (ret.code >= 200 and ret.code < 300) then
return false, nil, response or extra;
end
if type(response) ~= "table" or type(response[username_field]) ~= "string" then
return false, nil, nil;
end
return response[username_field], true, response;
end
end
return sasl.new(host, profile);
end
module:provides("auth", provider);