On Mon, Feb 17, 2020 at 6:31 PM Carsten Klein <c.kl...@datagis.com> wrote:
> Hi there, > > finally, I got my first Tomcat enhancement ready. You can view its code > at my Tomcat fork on GitHub: > > > https://github.com/cklein05/tomcat/tree/session-manager-persist-authentication > > Before I'm opening an enhancement in Tomcat's Bugzilla, maybe, Mark and > Christopher (or whoever else is interested), could you please have a > quick look at the code? > > BTW, recent versions of Tomcat do no longer save and store passwords in > GenericPrincipal. That makes using this enhancement even less critical. > Can you describe an actual use case for this ? Without clustering, I don't understand why the auth persistence is useful at all [when using clustering, the delta manager persists that auth information]. To be honest, that's also the case for session persistence itself, which does not provide a QoS level that is still relevant today. But the feature is already there [maybe it could be considered for removal in 10 actually ...]. Rémy > > > Some brief description of what I've done: > > 1. The new boolean option 'persistAuthentication' is implemented in > ManagerBase and so can be configured for StandardManager or > PersistentManager (defaults to false). Also added this to > mbeans-descriptor.xml, so it's writable through JMX. > > 2. That option is set for any new StandardSession upon creation (in > method ManagerBase.createSession(String)). Once a session got this > option, it's not being changed during the session's lifetime. > > 3. In StandardSession, method doWriteObject writes authentication > information (authType and principal) only, if 'persistAuthentication' is > true, the session is authenticated (authType or principal != null) and > principal is serializable. > > 4. The "is principal serializable" test is, by default, a deep > (expensive?) check, which actually serializes the whole principal object > to an ObjectOutputStream backed by a new NullInputStream, which just > discards all bytes written. This check can be skipped by setting system > property > org.apache.catalina.session.StandardSession.PRINCIPAL_SERIALIZABLE_CHECK > to false (defaults to true, however). If skipped, the principal is > considered serializable if (principal instanceof Serializable). That's > how the session's attribute values are checked for being serializable or > not. > > However, that is odd, if such a serialized object has a child object > which is not serializable. In that case, the ObjectOutputStream is left > in an inconsistent state and no so called fatal exception code is > written to the stream (that is, when reading such a stream, no > WriteAbortedException is not thrown for such an error). > > 5. A Boolean object is used as a tag/marker that determines, whether > authentication information is present id the stream or not. If none of > the above conditions are met, both authType and principal are not > serialized (than, only the initial Boolean false marker has been emitted > to the stream). > > BTW, the Boolean false marker is not even required (if there is no > authentication information in the stream) since the reading code works > fine without any Boolean in the stream. So emitting Boolean false for > signalling "no auth info" is actually optional (we could consider > omitting it). > > 6. When sessions are loaded, ManagerBase provides a > org.apache.catalina.util.CustomObjectInputStream instance to read > sessions from. That instance is configured with the session's > sessionAttributeValueClassNamePattern property. This essentially defines > the classes, session attribute values may consist of. This pattern > defaults to "java\\.lang\\.(?:Boolean|Integer|Long|Number|String)", so > only attributes with these simple types can be loaded from a session. > > That filter pattern is only in effect, if a security manager is active, > or if a pattern has been configured for the manager (e.g. in context.xml). > > Currently, however, all session data (including its base properties like > creationTime, isNew, isValid etc) is loaded with that filter mechanism > in place. Since those so called 'scalar instance properties' actually > only consist of those simple types, that was not a problem. > > However, loading the serialized principal from the object stream is now > subject to that filter mechanism (BTW, HA's DeltaManager and > DeltaSession just do not utilize the CustomObjectInputStream). > > Since, as the name implies, the sessionAttributeValueClassNamePattern > applies to attribute values only, I decided to give the > CustomObjectInputStream a boolean 'filterActive' property, which is set > to true, just before StandardSession starts deserializing attributes. > The initial value of 'filterActive' can be specified though the > constructor, to which both StandardManager and StoreBase pass false > (actually, only StandardManager and PersistenManager (through StoreBase) > do use the CustomObjectInputStream class). > > 7. Conclusion > > - Tomcat still builds with that enhancement in place > - The enhancement obviously works as expected > - Minor decisions can still be made (e.g. pull NullInputStream into a > new file, maybe in ...catalina.util) > - What about the Tomcat documentation? Where to document all this? > > > Carsten > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
