mod_auth_oauth_external: Support PLAIN via resource owner password grant
Might not be supported by the backend but PLAIN is the lowest common
denominator, so not having it would lock out a lot of clients.
--- a/mod_auth_oauth_external/README.md Thu Mar 16 12:45:22 2023 +0100
+++ b/mod_auth_oauth_external/README.md Thu Mar 16 12:45:52 2023 +0100
@@ -7,7 +7,7 @@
This module provides external authentication via an external [AOuth
2](https://datatracker.ietf.org/doc/html/rfc7628) authorization server
and supports the [SASL OAUTHBEARER authentication][rfc7628]
-mechanism.
+mechanism as well as PLAIN for legacy clients (this is all of them).
# How it works
@@ -15,6 +15,9 @@
the Authorization server to validate them, returning info about the user
back to Prosody.
+Alternatively for legacy clients, Prosody receives the users username
+and password and retrieves a token itself, then proceeds as above.
+
# Configuration
`oauth_external_discovery_url`
@@ -35,6 +38,21 @@
structure returned by the validation endpoint that contains the XMPP
localpart.
+## For SASL PLAIN
+
+`oauth_external_resource_owner_password`
+: Boolean. Defaults to `true`. Whether to allow the *insecure*
+ resource owner password grant and SASL PLAIN.
+
+`oauth_external_token_endpoint`
+: URL string. OAuth 2 [Token
+ Endpoint](https://www.rfc-editor.org/rfc/rfc6749#section-3.2) used
+ to retrieve token in order to then retrieve the username.
+
+`oauth_external_client_id`
+: String. Client ID used to identify Prosody during the resource owner
+ password grant.
+
# Compatibility
Version Status
--- a/mod_auth_oauth_external/mod_auth_oauth_external.lua Thu Mar 16 12:45:22 2023 +0100
+++ b/mod_auth_oauth_external/mod_auth_oauth_external.lua Thu Mar 16 12:45:52 2023 +0100
@@ -6,12 +6,14 @@
-- TODO -- local issuer_identity = module:get_option_string("oauth_external_issuer");
local oidc_discovery_url = module:get_option_string("oauth_external_discovery_url")
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???
--- TODO -- local client_id = module:get_option_string("oauth_external_client_id");
+local client_id = module:get_option_string("oauth_external_client_id");
-- TODO -- local client_secret = module:get_option_string("oauth_external_client_secret");
--[[ More or less required endpoints
@@ -29,6 +31,46 @@
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)
+ 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;
+ username = map_username(username, realm);
+ password = password;
+ scope = "openid";
+ });
+ }))
+ 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
+ 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
function profile:oauthbearer(token)
if token == "" then
return false, nil, extra;