I'd like to backport this to the 3.8 branch too.
Let's say I'll add new "zookeeper.fips-mode" parameter which will be
"false" by default in 3.8 and "true" for 3.9.0.
Thoughts?
Andor
On Fri, 2023-06-09 at 13:55 +0200, Enrico Olivelli wrote:
> I think that switching to
> sslParameters.setEndpointIdentificationAlgorithm("HTTPS"); is a good
> option.
> The less tweaks we have about Security code the better.
>
>
> It would be great to see this in 3.9.0.
>
> Enrico
>
> Il giorno ven 9 giu 2023 alle ore 13:42 Andor Molnar
> <an...@apache.org> ha scritto:
> > Hi zk folks,
> >
> > Problem(s)
> > ==========
> >
> > One problem that we're having with a custom Trust Manager in ZK is
> > that
> > FIPS doesn't allow that:
> >
> > https://issues.apache.org/jira/browse/ZOOKEEPER-4393
> >
> > In FIPS mode the only allowed TrustManager in the JDK is
> > X509TrustManagerImpl which is the default implementation. The class
> > is
> > final, so extending it is not an option unfortunately.
> >
> > The intention behind implementing a custom trust manager in ZK was,
> > I
> > believe, the need for server and client-side hostname verification.
> > Hostname verification officially is not part of the SSL/TLS
> > protocol,
> > it's the responsibility of an upper level protocol like HTTPS.
> >
> > Hacking hostname verification in the SSL handshake is nice and was
> > working fine so far, but unfortunately breaks the FIPS standard.
> >
> > Another annoying issue with ZKTrustManager is the need for reverse
> > DNS
> > lookup. This is usually needed when the hostname of the certificate
> > provider is not known at the time of handshake. For instance, when
> > somebody connects the client via IP address, which is generally not
> > recommended when TLS is active in the client-server protocol.
> >
> > The bigger problem I've found is in the leader election: when a
> > peer
> > connects with a smaller id, the node will close the existing
> > connection
> > and opens a new one in the other direction, based on the
> > information
> > received in the InitialMessage from the peer which only contains
> > the IP
> > address, not the hostname. Therefore TrustManager needs to perform
> > reverse DNS lookup.
> >
> > Tickets about reverse DNS lookup issues:
> > https://issues.apache.org/jira/browse/ZOOKEEPER-3860
> > https://issues.apache.org/jira/browse/ZOOKEEPER-4268
> >
> > Proposal
> > ========
> >
> > I suggest to remove ZKTrustManager entirely from the codebase and
> > use
> > the built-in, FIPS-Enabled X509TrustManagerImpl instead. It has the
> > downside of losing hostname verification, but we have an option to
> > re-
> > enable it in client-server communication: Netty has built-in
> > support
> > for it, we just need to do
> >
> > sslParameters.setEndpointIdentificationAlgorithm("HTTPS");
> >
> > when creating the SSLEngine and that will result in a behaviour
> > very
> > similar to what we provide currently. I can show some examples.
> >
> > What we will truly lose is the hostname verification option in the
> > Quorum and Leader Election protocols. Since in these protocols we
> > manipulate the sockets directly, we would need to implement the
> > verification manually.
> >
> > What do you think about this trade-off?
> >
> > Of course, we can put this change behind a feature flag "fips-
> > mode",
> > which will lead to a new mode in ZooKeeper that is actually less
> > strict
> > as the original behaviour.
> >
> > Regards,
> > Andor
> >
> >
> >
