[keycloak-dev] PKCE support for Keycloak Adapters (OAuthRequestAuthenticator)

Thomas Darimont thomas.darimont at googlemail.com
Tue Jun 12 13:23:25 EDT 2018 

Thanks, I found it, updated the PR with tests for PKCE methods 'S256' and
'plain'.
One thing left is to properly isolate the two support libraries - which
register
the `sha256` and `base64js` in global scope.

One caveat here is that this might break existing apps / integrations which
are currently
using other objects with those names.
To work around this issue, one could try to register those functions in a
custom root object
like "Keycloak.libs" instead of window, and then use Keycloak.libs.sha256...
and Keycloak.libs.base64js...

Stian Thorgersen <sthorger at redhat.com> schrieb am Di., 12. Juni 2018, 17:35:

> There's a JavaScript adapter test in the base testsuite. On my phone now
> so can't find the correct name. Probably called JavaScriptAdapterTest or
> something like that.
>
> On Fri, 8 Jun 2018, 18:35 Thomas Darimont, <thomas.darimont at googlemail.com>
> wrote:
>
>> Hi Marek,
>>
>> thanks for your helpful feedback!
>> I extracted the generateRandomData() function from the
>> generateCodeVerifier() function, which could be
>> reused for state and UUID generation. I also added a fallback in case
>> Uint8Array isn't available.
>>
>> I created a PR with the current implementation for KEYCLOAK-1033 (the
>> issue subject should be adapted to this)
>> https://github.com/keycloak/keycloak/pull/5255
>>
>> What's the best way to implement an automated for this?
>>
>> Cheers,
>> Thomas
>>
>> On Wed, Jun 6, 2018 at 9:12 AM Marek Posolda <mposolda at redhat.com> wrote:
>>
>>> Hi Thomas,
>>>
>>> I think it is great and will be good to support this in our javascript
>>> adapter OOTB.
>>>
>>> Few comments:
>>> - In keycloak.js, we use "createUUID()" function to generate "nonce" and
>>> "state" . IMO it will be good if all the things (nonce, state,
>>> codeVerifier...) are generated through same mechanism. I guess that we
>>> can use "window.crypto" or "window.msCrypto", but if none of them is
>>> available, then just fallback to what is currently used in
>>> "createUUID()" ? Also change the current generating of "nonce" and
>>> "state" to this as I suppose that "window.crypto" or "window.msCrypto"
>>> are safer alternatives than our current "createUUID()" ?
>>>
>>> - I have same concern as you about localStorage, but don't have any
>>> better alternative... No idea if sessionStorage is better.
>>>
>>> - We should document what browsers supports it. I guess that due to
>>> fallback for crypto/msCrypto, the "plain" method shouldn't be an issue
>>> for any browser as codeVerifier will be always generated just fine? But
>>> I guess that S256, which requires this "Uint8Array" stuff may have
>>> compatibility issues? Or am I wrong here? The issue is, that people can
>>> still use very old browsers (For example Windows XP with IE6) and not
>>> sure how bad it is if those people with old browsers can't
>>> authenticate...
>>>
>>> Marek
>>>
>>>
>>> On 05/06/18 21:33, Thomas Darimont wrote:
>>> > Hello,
>>> >
>>> > I gave it another spin and tested it with a whole bunch of browsers
>>> > - Windows (IE11, Edge, Firefox, Chrome)
>>> > - Linux (Chrome, Firefox)
>>> >
>>> > Current changes: (Added IE11 Support)
>>> >
>>> https://github.com/keycloak/keycloak/compare/master...thomasdarimont:poc/keycloak-js-pkce-support?expand=0
>>> >
>>> > If you want to give it a try, you could use the js-console example from
>>> >
>>> >
>>> https://github.com/keycloak/keycloak/blob/master/examples/js-console/src/main/webapp/index.html
>>> > and just copy the keycloak.js with the PKCE support into the webapp
>>> folder
>>> > an include the script from there.
>>> >
>>> > In the initOptions for Keycloak, just add "pkceMethod: 'S256'", e.g.:
>>> >
>>> >      var initOptions = {
>>> >          responseMode: 'fragment',
>>> >          flow: 'standard',
>>> >          pkceMethod: 'S256'
>>> >      };
>>> >
>>> > If you look at your browser dev-tools, you should now see,
>>> code_challenge
>>> > and code_challenge_method parameters added to your
>>> > /auth url. Additionally a code_verifier parameter should be sent with
>>> the
>>> > /token POST request.
>>> >
>>> > Some additional remarks:
>>> >
>>> > In order to support IE11 I had to use the window.msCrypto APIs and I
>>> added
>>> > a fallback if even that is not available.
>>> > Currently the generated code_verifier is stored in localStorage
>>> similar to
>>> > the 'kc-callback-...' values.
>>> > I think that localStorage is not the best place to store a temporary
>>> secret
>>> > ... I'm open to alternatives.
>>> >
>>> > The PKCE code_verifier is generated and stored in localStorage when
>>> > building the auth URL, where either
>>> > the plain value or an url-safe base64 encoded sha256 has of the
>>> > code_verifier is used as the code_challenge, depending on the chosen
>>> method.
>>> > Instead of localStorage one could probably also just use
>>> sessionStorage,
>>> > which would have the advantage of automatic deletion when the tab /
>>> browser
>>> > is closed.
>>> >
>>> > The two included libraries could be embedded / scoped into the
>>> keycloak JS
>>> > scope to not interfere with other included versions of the libraries.
>>> >
>>> > Cheers,
>>> > Thomas
>>> >
>>> > On Thu, May 31, 2018 at 1:09 PM Thomas Darimont <
>>> > thomas.darimont at googlemail.com> wrote:
>>> >
>>> >> Hi folks,
>>> >>
>>> >> I've got a working PoC for PKCE support in the Keycloak JS adapter
>>> that
>>> >> supports `plain` and `S256` code_challenge_methods.
>>> >> Works very well with Keycloak 4.0.0.beta3 and Keycloak 3.4.3.Final.
>>> >> Perhaps this could serve as a base for a real PR.
>>> >>
>>> >> I needed to use two small js libraries to have proper support for
>>> sha256
>>> >> and base64 encoding for Unit8Arrays in order to
>>> >> produce a codeChallenge in the same way the Keycloak server does it,
>>> for
>>> >> details see commit.
>>> >>
>>> >> Branch:
>>> >>
>>> https://github.com/thomasdarimont/keycloak/tree/poc/keycloak-js-pkce-support
>>> >> Commit:
>>> >>
>>> https://github.com/thomasdarimont/keycloak/commit/f05066d430f6504246f7e518a124aef2ef5195b8
>>> >>
>>> >> Looks like this would solve the issue
>>> >> https://issues.jboss.org/browse/KEYCLOAK-1033 (which would probably
>>> need
>>> >> to be renamed).
>>> >>
>>> >> Cheers,
>>> >> Thomas
>>> >>
>>> >> On Wed, May 30, 2018 at 11:57 PM Thomas Darimont <
>>> >> thomas.darimont at googlemail.com> wrote:
>>> >>
>>> >>> Good point. Yes the main use case for PKCE are public clients /
>>> native
>>> >>> apps.
>>> >>>
>>> >>> However the recently published OAuth 2.0 Security Best Current
>>> Practice
>>> >>> (Draft 06 2018) [1] states:
>>> >>> "
>>> >>> 2.1.  Protecting redirect-based flows
>>> >>> ...
>>> >>>   Clients shall use PKCE [RFC7636] in order to (with the help of the
>>> >>>     authorization server) detect and prevent attempts to inject
>>> (replay)
>>> >>>     authorization codes into the authorization response.  The PKCE
>>> >>>     challenges must be transaction-specific and securely bound to the
>>> >>>     user agent, in which the transaction was started.  OpenID Connect
>>> >>>     clients may use the "nonce" parameter of the OpenID Connect
>>> >>>     authentication request as specified in [OpenID] in conjunction
>>> with
>>> >>>     the corresponding ID Token claim for the same purpose.
>>> >>>
>>> >>> Note: although PKCE so far was recommended as mechanism to protect
>>> >>>     native apps, this advice applies to all kinds of OAuth clients,
>>> >>>     including web applications.
>>> >>> "
>>> >>> The last "Note" section was what inspired me to look into PKCE
>>> support
>>> >>> for server-side adapters as well.
>>> >>> But I generally agree that this is probably better suited for the JS
>>> /
>>> >>> CLI/ keycloak-installed adapters.
>>> >>>
>>> >>> [1] https://tools.ietf.org/html/draft-ietf-oauth-security-topics-06
>>> >>>
>>> >>> On Wed, May 30, 2018 at 8:38 AM Stian Thorgersen <
>>> sthorger at redhat.com>
>>> >>> wrote:
>>> >>>
>>> >>>> As PKCE is aimed at public clients why is there a need to add
>>> support
>>> >>>> for this to the Java adapters? Makes more sense to add this to the
>>> >>>> JavaScript adapter and CLI/desktop adapter.
>>> >>>>
>>> >>>> On 30 May 2018 at 07:47, 乗松隆志 / NORIMATSU，TAKASHI <
>>> >>>> takashi.norimatsu.ws at hitachi.com> wrote:
>>> >>>>
>>> >>>>> Hello,
>>> >>>>>
>>> >>>>> I've encountered the same problem and gave up.
>>> >>>>>
>>> >>>>> At that time, the naive idea had hit on me.
>>> >>>>> * prepare some concurrently accessible singleton (line
>>> >>>>> KeycloakDeployment) from OAuthRequestAuthenticator
>>> >>>>> * store generated codeVerifier on it with state parameter value as
>>> its
>>> >>>>> key.
>>> >>>>>
>>> >>>>> But, considering the nature of codeVerifier, the followings are
>>> >>>>> required for such the store
>>> >>>>> * codeVerifier should be treated the same secure levels as client
>>> >>>>> credentials
>>> >>>>> * codeVerifier should be short-lived and deleted after its life the
>>> >>>>> same as Authorization Code
>>> >>>>>
>>> >>>>> Therefore, It might be better to create an tentative instance whose
>>> >>>>> lifetime is between issuing Authorization Code Request and issuing
>>> Token
>>> >>>>> Request. And, it should be identified and only accessible from the
>>> session
>>> >>>>> instance who issued Authorization Code Request.
>>> >>>>>
>>> >>>>> However, I'm afraid it might be difficult to accomplish it in
>>> generic
>>> >>>>> fashion. We need to implement the above each type of client
>>> adapter.
>>> >>>>>
>>> >>>>> Best regards,
>>> >>>>> Takashi Norimatsu
>>> >>>>> Hitachi Ltd.,
>>> >>>>>
>>> >>>>> -----Original Message-----
>>> >>>>> From: keycloak-dev-bounces at lists.jboss.org <
>>> >>>>> keycloak-dev-bounces at lists.jboss.org> On Behalf Of Thomas Darimont
>>> >>>>> Sent: Wednesday, May 30, 2018 9:02 AM
>>> >>>>> To: keycloak-dev <keycloak-dev at lists.jboss.org>
>>> >>>>> Subject: [!][keycloak-dev] PKCE support for Keycloak Adapters
>>> >>>>> (OAuthRequestAuthenticator)
>>> >>>>>
>>> >>>>> Hi there,
>>> >>>>>
>>> >>>>> I was recently playing with the PKCE support in Keycloak (server)
>>> which
>>> >>>>> worked quite well.
>>> >>>>> However the support for client / adapters seems to be quite
>>> limited at
>>> >>>>> the moment...
>>> >>>>>
>>> >>>>> I think support for PKCE to all? java adapters could be added quite
>>> >>>>> easily
>>> >>>>> - I could provide a
>>> >>>>> PR but I'm currently stuck with finding a generic way to store the
>>> >>>>> codeVerifier generated for the login redirect for later retrival
>>> for the
>>> >>>>> code2token exchange.
>>> >>>>>
>>> >>>>> Do you have any recommendations for this?
>>> >>>>>
>>> >>>>> I created the following JIRA issue (with some comments) to track
>>> this:
>>> >>>>>
>>> >>>>>
>>> https://clicktime.symantec.com/a/1/bkUjActRvyW1Ds3zoQSu7mjr4Nabixm_1YJAW4-UxEM=?d=d5OUWVTwLT2kMkuISm5qn8WHJTBcSVkENKzaB0Z2mA-PX8kp40LeKyOrcMpyKd841kYgP2EXaDDWYa0qu-AFLCtVLO4LvMfUJgUhu3xFwONMPy78dypmmmeEalkcYLU4XY3LcstbfVAoE0jRdEXXMyYStWwO95V_98pfhIYFlYFIHgapXJsFfGrldL8-siYGhinjnCn_AWyuyqrwhvBY582Dr3Pn9k4YZfsudBwcSJkErQKzyYEKfMhwz4ix7EAa-hvQ6rGHFdSza3jf1cMjsR4Xio667eNtirL9ruV4Z-FFQhamJMSJGb2o8rR52iEuGTp_28Vivk5HiwYx5XhZ4Bm9_dhN2eNeWT396bZQJwC7tDetr6UPVrPiMn6aTLdGMu6Wr-byBNvnEFmqxCB0Cx1tPxQkO4DVWKF4_iWgxZ6sW49k87BqaRTp3ktECRXNJ-CA04UZQbL7w-uPYlxvyvNNl408bCn5LpYf8w%3D%3D&u=https%3A%2F%2Fissues.jboss.org%2Fbrowse%2FKEYCLOAK-7467
>>> >>>>>
>>> >>>>> Cheers,
>>> >>>>> Thomas
>>> >>>>> _______________________________________________
>>> >>>>> keycloak-dev mailing list
>>> >>>>> keycloak-dev at lists.jboss.org
>>> >>>>>
>>> >>>>>
>>> https://clicktime.symantec.com/a/1/Xn2ffdZIVPL_UA8_cnNApcirkcZZdsnyb6SpUdKiO-s=?d=d5OUWVTwLT2kMkuISm5qn8WHJTBcSVkENKzaB0Z2mA-PX8kp40LeKyOrcMpyKd841kYgP2EXaDDWYa0qu-AFLCtVLO4LvMfUJgUhu3xFwONMPy78dypmmmeEalkcYLU4XY3LcstbfVAoE0jRdEXXMyYStWwO95V_98pfhIYFlYFIHgapXJsFfGrldL8-siYGhinjnCn_AWyuyqrwhvBY582Dr3Pn9k4YZfsudBwcSJkErQKzyYEKfMhwz4ix7EAa-hvQ6rGHFdSza3jf1cMjsR4Xio667eNtirL9ruV4Z-FFQhamJMSJGb2o8rR52iEuGTp_28Vivk5HiwYx5XhZ4Bm9_dhN2eNeWT396bZQJwC7tDetr6UPVrPiMn6aTLdGMu6Wr-byBNvnEFmqxCB0Cx1tPxQkO4DVWKF4_iWgxZ6sW49k87BqaRTp3ktECRXNJ-CA04UZQbL7w-uPYlxvyvNNl408bCn5LpYf8w%3D%3D&u=https%3A%2F%2Flists.jboss.org%2Fmailman%2Flistinfo%2Fkeycloak-dev
>>> >>>>>
>>> >>>>> _______________________________________________
>>> >>>>> keycloak-dev mailing list
>>> >>>>> keycloak-dev at lists.jboss.org
>>> >>>>> https://lists.jboss.org/mailman/listinfo/keycloak-dev
>>> >>>>>
>>> >>>>
>>> > _______________________________________________
>>> > keycloak-dev mailing list
>>> > keycloak-dev at lists.jboss.org
>>> > https://lists.jboss.org/mailman/listinfo/keycloak-dev
>>>
>>>
>>>

More information about the keycloak-dev mailing list