mod_http_oauth2: Allow requesting a subset of scopes on token refresh
This enables clients to request access tokens with fewer permissions
than the grant they were given, reducing impact of token leak. Clients
could e.g. request access tokens with some privileges and immediately
revoke them after use, or other strategies.
--- a/mod_http_oauth2/mod_http_oauth2.lua Thu May 11 19:33:44 2023 +0200
+++ b/mod_http_oauth2/mod_http_oauth2.lua Thu May 11 21:40:09 2023 +0200
@@ -411,14 +411,22 @@
end
local refresh_scopes = refresh_token_info.grant.data.oauth2_scopes;
+
+ if params.scope then
+ local granted_scopes = set.new(parse_scopes(refresh_scopes));
+ local requested_scopes = parse_scopes(params.scope);
+ refresh_scopes = array.filter(requested_scopes, function(scope)
+ return granted_scopes:contains(scope);
+ end):concat(" ");
+ end
+
+ local username = jid.split(refresh_token_info.jid);
local new_scopes, role = filter_scopes(username, refresh_scopes);
-- new_access_token() requires the actual token
refresh_token_info.token = params.refresh_token;
- return json.encode(new_access_token(
- refresh_token_info.jid, role, new_scopes, client, nil, refresh_token_info
- ));
+ return json.encode(new_access_token(refresh_token_info.jid, role, new_scopes, client, nil, refresh_token_info));
end
-- RFC 7636 Proof Key for Code Exchange by OAuth Public Clients