Apache Pulsar's MultiRolesTokenAuthorizationProvider authorizes a client with all roles listed in...

Apache Pulsar's MultiRolesTokenAuthorizationProvider authorizes a client with all roles listed in a claim of its JSON Web Token (JWT). The provider is intended for use with token authentication, which verifies the token before authorization. The provider did not verify the token itself: it parsed the token's claims with the signature removed and trusted that authentication had already checked it.

When authentication and authorization are enabled with a non-empty anonymousUserRole setting, some HTTP requests whose credentials fail authentication are not rejected, but are handled as requests of the anonymous user role. For the broker's HTTP endpoints, such as the admin REST API, this fallback applies to requests that do not name an authentication method and requires strictAuthMethod to be false (the default) where that setting is available. For the WebSocket API, failed credentials can also fall back to the anonymous user role; this path does not enforce strictAuthMethod. The authentication data kept for such a request still contained the request's Authorization header. MultiRolesTokenAuthorizationProvider then read the bearer token from that header without verifying its signature and authorized the request with the roles in the token's role claim.

As a result, in deployments that use MultiRolesTokenAuthorizationProvider together with a non-empty anonymousUserRole and that permit this fallback, an unauthenticated client can send an HTTP request, for example to the admin REST…