Thanks for the KIP, +1 (non binding)
On Wed, May 16, 2018 at 2:51 AM, Ron Dagostino <rndg...@gmail.com> wrote: > Hi Jun. I think you are getting at the fact that OAuth 2 is a flexible > framework that allows different installations to do things differently. It > is true that the principal name in Kafka could come from any claim in the > token. Most of the time it would come from the 'sub' claim, but it could > certainly come from another claim, or it could be only indirectly based on > a claim value (maybe certain text would be trimmed or prefixed/suffixed). > The point, which I think you are getting at, is that because the framework > is flexible we need to accommodate that flexibility. The callback handler > class defined by the listener.name.sasl_ssl.oauthbearer.sasl.server. > callback.handler.class configuration value gives us the required > flexibility. As an example, I have an implementation that leverages a > popular open source JOSE library to parse the compact serialization, > retrieve the public key if it has not yet been retrieved, verify the > digital signature, and map the 'sub' claim to the OAuthBearerToken's > principal name (which becomes the SASL authorization ID, which becomes the > Kafka principal name). I could just as easily have mapped a different > claim to the OAuthBearerToken's principal name, manipulated the 'sub' claim > value in some way, etc. I write the callback handler code, so I complete > flexibility to do whatever my OAuth 2 installation requires me to do. > > Ron > > On Tue, May 15, 2018 at 1:39 PM, Jun Rao <j...@confluent.io> wrote: > >> Hi, Ron, >> >> Thanks for the reply. I understood your answers to #2 and #3. >> >> For #1, will the server map all clients' principal name to the value >> associated with "sub" claim? How do we support mapping different clients to >> different principal names? >> >> Jun >> >> On Mon, May 14, 2018 at 7:02 PM, Ron Dagostino <rndg...@gmail.com> wrote: >> >> > Hi Jun. Thanks for the +1 vote. >> > >> > Regarding the first question about token claims, yes, you have it correct >> > about translating the OAuth token to a principle name via a JAAS module >> > option in the default unsecured case. Specifically, the OAuth SASL >> Server >> > implementation is responsible for setting the authorization ID, and it >> gets >> > the authorization ID from the OAuthBearerToken's principalName() method. >> > The listener.name.sasl_ssl.oauthbearer.sasl.server. >> callback.handler.class >> > is responsible for handling an instance of OAuthBearerValidatorCallback >> to >> > accept a token compact serialization from the client and return an >> instance >> > of OAuthBearerToken (assuming the compact serialization validates), and >> in >> > the default unsecured case the builtin unsecured validator callback >> handler >> > defines the OAuthBearerToken.principalName() method to return the 'sub' >> > claim value by default (with the actual claim it uses being configurable >> > via the unsecuredValidatorPrincipalClaimName JAAS module option). So >> that >> > is how we translate from a token to a principal name in the default >> > unsecured (out-of-the-box) case. >> > >> > For production use cases, the implementation associated with >> > listener.name.sasl_ssl.oauthbearer.sasl.server.callback.handler.class >> can >> > do whatever it wants. As an example, I have written a class that wraps a >> > com.nimbusds.jwt.SignedJWT instance (see >> > https://connect2id.com/products/nimbus-jose-jwt/) and presents it as an >> > OAuthBearerToken: >> > >> > public class NimbusSignedJwtOAuthBearerToken implements >> OAuthBearerToken { >> > private final SignedJWT signedJwt; >> > private final String principalName; >> > private final Set<String> scope; >> > private final Long startTimeMs; >> > private final long lifetimeMs; >> > >> > /** >> > * Constructor >> > * >> > * @param signedJwt >> > * the mandatory signed JWT >> > * @param principalClaimName >> > * the mandatory claim name identifying the claim from >> which >> > the >> > * principal name will be extracted. The claim must exist >> > and must be >> > * a String. >> > * @param optionalScopeClaimName >> > * the optional claim name identifying the claim from >> which >> > any scope >> > * will be extracted. If specified and the claim exists >> then >> > the >> > * value must be either a String or a String List. >> > * @throws ParseException >> > * if the principal claim does not exist or is not a >> > String; the >> > * scope claim is neither a String nor a String List; the >> > 'exp' >> > * claim does not exist or is not a number; the 'iat' >> claim >> > exists >> > * but is not a number; or the 'nbf' claim exists and is >> > not a >> > * number. >> > */ >> > public NimbusSignedJwtOAuthBearerToken(SignedJWT signedJwt, String >> > principalClaimName, >> > String optionalScopeClaimName) throws ParseException { >> > // etc... >> > } >> > >> > The callback handler runs the following code if the digital signature >> > validates: >> > >> > callback.token(new NimbusSignedJwtOAuthBearerToken(signedJwt, "sub", >> > null)); >> > >> > I hope that answers the first question. If not let me know what I >> > missed/misunderstood and I'll be glad to try to address it. >> > >> > Regarding the second question, the classes OAuthBearerTokenCallback and >> > OAuthBearerValidatorCallback implement the Callback interface -- they are >> > the callbacks that the AuthenticateCallbackHandler implementations need >> to >> > handle. Specifically, unless the unsecured functionality is what is >> > desired, the two configuration values [listener.name.sasl_ssl. >> oauthbearer. >> > ]sasl.login.callback.handler.class and >> > listener.name.sasl_ssl.oauthbearer.sasl.server.callback.handler.class >> > define the callback handlers that need to handle OAuthBearerTokenCallback >> > and OAuthBearerValidatorCallback, respectively. >> > >> > Regarding the third question, yes, I see your point that the way the spec >> > is worded could be taken to imply that the error code is a single >> > character: "A single ASCII..." ( >> > https://tools.ietf.org/html/rfc6749#section-5.2). However, it is not a >> > single character. See the end of that section 5.2 for an example that >> > shows "error":"invalid_request" as the response. >> > >> > Thanks again for the +1 vote, Jun, and please do let me know if I can >> cover >> > anything else. >> > >> > Ron >> > >> > >> > On Mon, May 14, 2018 at 7:10 PM, Jun Rao <j...@confluent.io> wrote: >> > >> > > Hi, Ron, >> > > >> > > Thanks for the KIP. +1 from me. Just a few minor comments below. >> > > >> > > 1. It seems that we can translate an OAuth token to a principle name >> > > through the claim name configured in JASS. However, it's not clear to >> me >> > > how an OAuth token is mapped to a claim. Could you clarify that? >> > > >> > > 2. The wiki has the following code. It seems that >> > OAuthBearerTokenCallback >> > > should implement AuthenticateCallbackHandler? Ditto >> > > for OAuthBearerValidatorCallback. >> > > >> > > public class OAuthBearerTokenCallback implements Callback >> > > >> > > 3. In OAuthBearerTokenCallback, we have the following method. The OAuth >> > > spec says the error code is a single ASCII. So, should we return a Char >> > or >> > > a String? >> > > >> > > public String errorCode() >> > > >> > > Jun >> > > >> > > >> > > On Thu, May 3, 2018 at 8:55 PM, Ron Dagostino <rndg...@gmail.com> >> wrote: >> > > >> > > > Hi everyone. I would like to start the vote for KIP-255: >> > > > https://cwiki.apache.org/confluence/pages/viewpage. >> > > action?pageId=75968876 >> > > > >> > > > This KIP proposes to add the following functionality related to >> > > > SASL/OAUTHBEARER: >> > > > >> > > > 1) Allow clients (both brokers when SASL/OAUTHBEARER is the >> > inter-broker >> > > > protocol as well as non-broker clients) to flexibly retrieve an >> access >> > > > token from an OAuth 2 authorization server based on the declaration >> of >> > a >> > > > custom login CallbackHandler implementation and have that access >> token >> > > > transparently and automatically transmitted to a broker for >> > > authentication. >> > > > >> > > > 2) Allow brokers to flexibly validate provided access tokens when a >> > > client >> > > > establishes a connection based on the declaration of a custom SASL >> > Server >> > > > CallbackHandler implementation. >> > > > >> > > > 3) Provide implementations of the above retrieval and validation >> > features >> > > > based on an unsecured JSON Web Token that function out-of-the-box >> with >> > > > minimal configuration required (i.e. implementations of the two types >> > of >> > > > callback handlers mentioned above will be used by default with no >> need >> > to >> > > > explicitly declare them). >> > > > >> > > > 4) Allow clients (both brokers when SASL/OAUTHBEARER is the >> > inter-broker >> > > > protocol as well as non-broker clients) to transparently retrieve a >> new >> > > > access token in the background before the existing access token >> expires >> > > in >> > > > case the client has to open new connections. >> > > > >> > > > Thanks, >> > > > >> > > > Ron >> > > > >> > > >> > >>
