[keycloak-dev] File-based Vault implementation

Hynek Mlnarik hmlnarik at redhat.com
Fri Aug 9 08:46:46 EDT 2019


I agree that certain level of cacheability should be there, however its
being enabled needs to be decided by an administrator.

If the admin decides to use vault for secrets, we should employ all
measures for obtaining it only when needed. If they decide a secret is safe
to cache it in Keycloak, then we should support it. Both modes can be
implemented for the vault provider (note caching is implementation
dependent, see below), but here I'd start with the strictest and safest
option of accessing the vault whenever needed. As Sebastian pointed out,
the sample implementation might be very fast, even though certainly slower
than putting a secret directly into one of the models. Once this is done,
we can work on caching.

Caching the secrets is connected with invalidation and that is dependent on
actual vault implementation. The secret value can change over time, and
we'd need to adjust / invalidate the cached value. For example if
Kubernetes secrets change in the file, they are immediately propagated to a
running pod, and we should pick up the new value. Since this is based on
files, we would need to invalidate / reload the entry if file modification
time changes.

On Fri, Aug 9, 2019 at 10:56 AM Sebastian Laskawiec <slaskawi at redhat.com>
wrote:

> At least for File-based Vault implementation, I would like to experiment a
> bit with MappedByteBuffers [1] (the PR still contains the old code, I'm
> about to update very soon). If that goes well, we should get a sort of
> trade-off between performance (reading the same secret over and over should
> be blazing fast) and security (the caller of the vault will obtain a secret
> and the override it with random data when it's done using it).
>
> But that's actually a good point - we should run a performance test (or
> profile the code using Flight Recorder) once the implementation is ready.
>
> [1] https://www.baeldung.com/java-mapped-byte-buffer
>
> On Thu, Aug 8, 2019 at 7:24 PM Marek Posolda <mposolda at redhat.com> wrote:
>
> > I am sorry for joining late.
> >
> > I guess you already take performance into account, but still I would
> > like to point it again here. Because usually there is some trade-off
> > between performance and security :)
> >
> > IMO the important question is at which point exactly the vault will be
> > called? Will it be directly when particular value (eg. client secret) is
> > retrieved from DB, so the secret would be still cached in memory as it
> > is today? Or do you want to prevent caching secrets at all? I would
> > personally prefer the first option by default due the better performance
> > and eventually allow the second option in case that people prefer
> > stronger security against performance.
> >
> > For example clientSecret is always needed when refreshing token,
> > exchanging code-to-token etc. So if you always need to read the file
> > during each refreshToken request, it is not ideal. I see the main point
> > of the vault is to prevent plain-text passwords in DB. The prevention of
> > have secrets in memory is not so big priority if it means the
> > significant performance degradation IMO.
> >
> > Marek
> >
> >
> > On 08. 08. 19 14:35, Pedro Igor Silva wrote:
> > > On Thu, Aug 8, 2019 at 4:34 AM Sebastian Laskawiec <
> slaskawi at redhat.com>
> > > wrote:
> > >
> > >> I briefly looked at the SPI and it seems a bit over the top comparing
> to
> > >> what we need. Plus we would create a strong connection between
> Keycloak
> > and
> > >> Elytron Security SPIs and I'm not sure if this is desirable.
> > >>
> > >> Maybe a translation layer (a simple Vault SPI implementation that
> > >> delegates to Elytron SPIs) would be better?
> > >>
> > > Yeah, it is. Like I said, for this particular case your SPI is more
> > simple
> > > and you won't get much from Elytron.
> > >
> > >
> > >>> For read-write, you have the key store implementation from Elytron
> that
> > >>> can save you some time. So your credentials are stored more securely
> > and
> > >>> you can easily look up them.
> > >>>
> > >> I agree with you here. The write path of the Vault SPI is a bit
> tricky.
> > >> But I'm not sure if that will happen (we will probably see in the
> > future).
> > >>
> > >> My personal vote here is to leave the door open and implement a
> > delegation
> > >> layer to Elytron SPIs. We can leave that as an Experimental Feature if
> > we
> > >> want to avoid extensive testing on the product side.
> > >>
> > > I see. If you are not planning to deliver the write path anytime soon,
> > > let's talk more about it later.
> > >
> > > Thanks.
> > >
> > >
> > >>
> > >>> I just wanted to let you know about Elytron Credential Store. I
> haven't
> > >>> joined the discussions about the credential store proposal so I may
> be
> > just
> > >>> messing your thread :)
> > >>>
> > >>> On Tue, Aug 6, 2019 at 10:35 AM Sebastian Laskawiec <
> > slaskawi at redhat.com>
> > >>> wrote:
> > >>>
> > >>>> The idea sounds interesting to me. Although, having in mind our
> plans
> > >>>> related to Keycloak.next, I'm not sure if we should provide it out
> of
> > the
> > >>>> box.
> > >>>>
> > >>>> Perhaps we should provide a community-driven extension (as a
> separate
> > >>>> jar) to use this?
> > >>>>
> > >>>> On Tue, Aug 6, 2019 at 2:59 PM Pedro Igor Silva <psilva at redhat.com>
> > >>>> wrote:
> > >>>>
> > >>>>> Hey Hynek,
> > >>>>>
> > >>>>> Elytron came into my mind because it provides an SPI for plugging
> > >>>>> different implementations based on a SPI [1]. There are some OOTB
> > >>>>> implementations such as a keystore-based and map-based.
> > >>>>>
> > >>>>> You should be able to delegate to other vault types or even build
> > your
> > >>>>> own on top of some default implementation. Considering that Elytron
> > >>>>> Subsystem is available as a subsystem you also have the necessary
> > means to
> > >>>>> manage your credential stores (via CLI, etc).
> > >>>>>
> > >>>>> [1]
> > >>>>>
> >
> https://github.com/wildfly-security/wildfly-elytron/blob/1c42623a343e138ac4a31bd5dcfd8d2ccc47633e/credential/store/src/main/java/org/wildfly/security/credential/store/CredentialStoreSpi.java#L35
> > >>>>>
> > >>>>> On Tue, Aug 6, 2019 at 3:37 AM Hynek Mlnarik <hmlnarik at redhat.com>
> > >>>>> wrote:
> > >>>>>
> > >>>>>> Hi Pedro,
> > >>>>>>
> > >>>>>> Elytron Cred Store has been considered, any details would be
> > >>>>>> appreciated. Specifically, does it support delegation to other
> > vault types?
> > >>>>>> Is it able to delegate access to other vault types, e.g.
> Kubernetes
> > >>>>>> credentials? See [1] for further context.
> > >>>>>>
> > >>>>>> Pros and cons of other vault implementations are highly
> appreciated
> > as
> > >>>>>> well. The number of built-in implementations mus be kept low (one
> > or two)
> > >>>>>> for maintenance reasons, so we need convincing arguments for
> > including any
> > >>>>>> in Keycloak. On the other hand, support for other vault types can
> be
> > >>>>>> contributed as a Community Extension [2].
> > >>>>>>
> > >>>>>> --Hynek
> > >>>>>>
> > >>>>>> [1]
> > >>>>>>
> >
> https://github.com/keycloak/keycloak-community/pull/18#discussion_r304860227
> > >>>>>> [2] https://www.keycloak.org/extensions.html
> > >>>>>>
> > >>>>>> On Mon, Aug 5, 2019 at 2:55 PM Pedro Igor Silva <
> psilva at redhat.com>
> > >>>>>> wrote:
> > >>>>>>
> > >>>>>>> Hi Sebastian,
> > >>>>>>>
> > >>>>>>> Elytron has a very powerful and flexible Credential Store SPI
> > (Peter
> > >>>>>>> can
> > >>>>>>> give more details) that can help managing credentials based on
> > keys.
> > >>>>>>> You
> > >>>>>>> could even use an implementation backed by a java key store (with
> > >>>>>>> in-memory
> > >>>>>>> support).
> > >>>>>>>
> > >>>>>>> Wouldn't make sense to use it or at least check how the design
> > could
> > >>>>>>> be
> > >>>>>>> improved to fit our requirements?
> > >>>>>>>
> > >>>>>>> Regards.
> > >>>>>>> Pedro Igor
> > >>>>>>>
> > >>>>>>> On Fri, Aug 2, 2019 at 6:39 AM Sebastian Laskawiec <
> > >>>>>>> slaskawi at redhat.com>
> > >>>>>>> wrote:
> > >>>>>>>
> > >>>>>>>> Hey,
> > >>>>>>>>
> > >>>>>>>> We are considering an initial, file-based Vault [1]
> implementation
> > >>>>>>> that
> > >>>>>>>> we'll ship out of the box. I imagine a minimum set of
> requirements
> > >>>>>>> as the
> > >>>>>>>> following:
> > >>>>>>>> - Easy to write by hand (for testing)
> > >>>>>>>> - Works out of the box in Kubernetes (Kubernetes can mount
> Secrets
> > >>>>>>> as
> > >>>>>>>> files)
> > >>>>>>>> - Make sure we do not cache file content anywhere, so we don't
> > >>>>>>> compromise a
> > >>>>>>>> secret value in Keycloak
> > >>>>>>>>
> > >>>>>>>> Essentially, there are two approaches for such an
> implementation.
> > >>>>>>>>
> > >>>>>>>> The first option is to put all secrets into a shared file
> > >>>>>>> representing
> > >>>>>>>> key-value pairs (a properties file is a natural candidate for
> such
> > >>>>>>> an
> > >>>>>>>> implementation). This approach very easy to use but it's pretty
> > >>>>>>> hard to
> > >>>>>>>> search for a particular key in a file. We would need to make
> sure
> > >>>>>>> that we
> > >>>>>>>> don't cache anything wile parsing the file (in
> BufferedInputStream
> > >>>>>>> for
> > >>>>>>>> example). Such an implementation would also be pretty slow,
> since
> > >>>>>>> whenever
> > >>>>>>>> we'd access the vault for a particular key, we would potentially
> > >>>>>>> need to
> > >>>>>>>> search the whole file.
> > >>>>>>>>
> > >>>>>>>> The second option is more complicated. Imagine the following
> file
> > >>>>>>> structure
> > >>>>>>>> (inside a vault directory):
> > >>>>>>>> my-secret-1 (secret value in its content)
> > >>>>>>>> my-secret-2 (secret value in its content)
> > >>>>>>>> my-secret-3 (secret value in its content)
> > >>>>>>>> In other words, each key is a file in a vault directory and its
> > >>>>>>> content
> > >>>>>>>> corresponds the secret value. Such an implementation is not very
> > >>>>>>> easy to
> > >>>>>>>> use as we'd need to create many small files. However, it's super
> > >>>>>>> fast for
> > >>>>>>>> searching and we can securely read the value without a risk of
> > >>>>>>> compromising
> > >>>>>>>> other secret values provided by the vault.
> > >>>>>>>>
> > >>>>>>>> I wonder what do you think about this? My personal take on this
> is
> > >>>>>>> that we
> > >>>>>>>> should provide both implementations. The former (single file)
> > would
> > >>>>>>> be used
> > >>>>>>>> in our testsuite (because of simplicity) and the latter
> (multiple
> > >>>>>>> files) in
> > >>>>>>>> production and in Kubernetes.
> > >>>>>>>>
> > >>>>>>>> Thanks,
> > >>>>>>>> Sebastian
> > >>>>>>>>
> > >>>>>>>> [1]
> > >>>>>>>>
> > >>>>>>>>
> > >>>>>>>
> >
> https://github.com/keycloak/keycloak-community/blob/master/design/secure-credentials-store.md
> > >>>>>>>> _______________________________________________
> > >>>>>>>> keycloak-dev mailing list
> > >>>>>>>> keycloak-dev at lists.jboss.org
> > >>>>>>>> https://lists.jboss.org/mailman/listinfo/keycloak-dev
> > >>>>>>>>
> > >>>>>>> _______________________________________________
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> > >>>>>>> https://lists.jboss.org/mailman/listinfo/keycloak-dev
> > >>>>>>>
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> >
> >
> >
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