Support Athenz authentication through x509 certificates

2 files changed, 142 insertions, 20 deletions

diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilter.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilter.java
index 328461355db..fc5536bb0f3 100644
--- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilter.java
+++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilter.java
@@ -7,17 +7,24 @@ import com.yahoo.jdisc.handler.ResponseHandler;
 import com.yahoo.jdisc.http.filter.DiscFilterRequest;
 import com.yahoo.jdisc.http.filter.SecurityRequestFilter;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.AthenzPrincipal;
-import com.yahoo.vespa.hosted.controller.api.integration.athenz.InvalidTokenException;
+import com.yahoo.vespa.hosted.controller.api.integration.athenz.AthenzUtils;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.NToken;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.ZmsKeystore;
 import com.yahoo.vespa.hosted.controller.athenz.config.AthenzConfig;
 
+import java.security.cert.X509Certificate;
+import java.util.Optional;
 import java.util.concurrent.Executor;
 
 import static com.yahoo.vespa.hosted.controller.athenz.filter.SecurityFilterUtils.sendErrorResponse;
 
 /**
- * Performs authentication by validating the principal token (NToken) header.
+ * Authenticates Athenz principal, either through:
+ *  1. TLS client authentication (based on Athenz x509 identity certficiate).
+ *  2. The principal token (NToken) header.
+ * The TLS authentication is based on the following assumptions:
+ *  - The underlying connector is configured with 'clientAuth' set to either WANT_AUTH or NEED_AUTH.
+ *  - The trust store is configured with the Athenz CA certificates only.
  *
  * @author bjorncs
  */
@@ -43,18 +50,45 @@ public class AthenzPrincipalFilter implements SecurityRequestFilter {
 
     @Override
     public void filter(DiscFilterRequest request, ResponseHandler responseHandler) {
-        String rawToken = request.getHeader(principalTokenHeader);
-        if (rawToken == null || rawToken.isEmpty()) {
-            sendErrorResponse(responseHandler, Response.Status.UNAUTHORIZED, "NToken is missing");
-            return;
-        }
         try {
-            AthenzPrincipal principal = validator.validate(new NToken(rawToken));
+            Optional<AthenzPrincipal> certificatePrincipal = getClientCertificate(request)
+                    .map(AthenzUtils::createAthenzIdentity)
+                    .map(AthenzPrincipal::new);
+            Optional<AthenzPrincipal> nTokenPrincipal = getPrincipalToken(request, principalTokenHeader)
+                    .map(validator::validate);
+
+            if (!certificatePrincipal.isPresent() && !nTokenPrincipal.isPresent()) {
+                String errorMessage = "Unable to authenticate Athenz identity. " +
+                        "Both client certificate missing and principal token header are missing.";
+                sendErrorResponse(responseHandler, Response.Status.UNAUTHORIZED, errorMessage);
+                return;
+            }
+            if (certificatePrincipal.isPresent() && nTokenPrincipal.isPresent()
+                    && !certificatePrincipal.get().equals(nTokenPrincipal.get())) {
+                String errorMessage = String.format(
+                        "Identity in principal token does not match x509 CN: token-identity=%s, cert-identity=%s",
+                        nTokenPrincipal.get().getIdentity().getFullName(),
+                        certificatePrincipal.get().getIdentity().getFullName());
+                sendErrorResponse(responseHandler, Response.Status.UNAUTHORIZED, errorMessage);
+                return;
+            }
+            AthenzPrincipal principal = nTokenPrincipal.orElseGet(certificatePrincipal::get);
             request.setUserPrincipal(principal);
             request.setRemoteUser(principal.getName());
-        } catch (InvalidTokenException e) {
+        } catch (Exception e) {
             sendErrorResponse(responseHandler,Response.Status.UNAUTHORIZED, e.getMessage());
         }
     }
 
+    private static Optional<X509Certificate> getClientCertificate(DiscFilterRequest request) {
+        return Optional.ofNullable((X509Certificate[]) request.getAttribute("jdisc.request.X509Certificate"))
+                .map(chain -> chain[0]);
+    }
+
+    private static Optional<NToken> getPrincipalToken(DiscFilterRequest request, String principalTokenHeaderName) {
+        return Optional.ofNullable(request.getHeader(principalTokenHeaderName))
+                .filter(token -> !token.isEmpty())
+                .map(NToken::new);
+    }
+
 }
diff --git a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilterTest.java b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilterTest.java
index ffb78b7342a..c887fbfc1a8 100644
--- a/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilterTest.java
+++ b/controller-server/src/test/java/com/yahoo/vespa/hosted/controller/athenz/filter/AthenzPrincipalFilterTest.java
@@ -7,10 +7,19 @@ import com.yahoo.jdisc.handler.ReadableContentChannel;
 import com.yahoo.jdisc.handler.ResponseHandler;
 import com.yahoo.jdisc.http.filter.DiscFilterRequest;
 import com.yahoo.vespa.hosted.controller.api.identifiers.UserId;
+import com.yahoo.vespa.hosted.controller.api.integration.athenz.AthenzIdentity;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.AthenzPrincipal;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.AthenzUser;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.InvalidTokenException;
 import com.yahoo.vespa.hosted.controller.api.integration.athenz.NToken;
+import org.bouncycastle.asn1.x500.X500Name;
+import org.bouncycastle.cert.X509v3CertificateBuilder;
+import org.bouncycastle.cert.jcajce.JcaX509CertificateConverter;
+import org.bouncycastle.cert.jcajce.JcaX509v3CertificateBuilder;
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+import org.bouncycastle.operator.ContentSigner;
+import org.bouncycastle.operator.OperatorCreationException;
+import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -18,6 +27,15 @@ import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.UncheckedIOException;
+import java.math.BigInteger;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.NoSuchAlgorithmException;
+import java.security.cert.CertificateException;
+import java.security.cert.X509Certificate;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.Date;
 import java.util.Objects;
 
 import static com.yahoo.jdisc.Response.Status.UNAUTHORIZED;
@@ -37,21 +55,21 @@ public class AthenzPrincipalFilterTest {
 
     private static final NToken NTOKEN = new NToken("dummy");
     private static final String ATHENZ_PRINCIPAL_HEADER = "Athenz-Principal-Auth";
+    private static final AthenzIdentity IDENTITY = AthenzUser.fromUserId(new UserId("bob"));
+    private static final X509Certificate CERTIFICATE = createSelfSignedCertificate(IDENTITY);
 
     private NTokenValidator validator;
-    private AthenzPrincipal principal;
 
     @Before
     public void before() {
         validator = mock(NTokenValidator.class);
-        principal = new AthenzPrincipal(AthenzUser.fromUserId(new UserId("bob")), NTOKEN);
     }
 
     @Test
-    public void valid_ntoken_is_accepted() throws Exception {
+    public void valid_ntoken_is_accepted() {
         DiscFilterRequest request = mock(DiscFilterRequest.class);
+        AthenzPrincipal principal = new AthenzPrincipal(IDENTITY, NTOKEN);
         when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(NTOKEN.getRawToken());
-
         when(validator.validate(NTOKEN)).thenReturn(principal);
 
         AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
@@ -61,7 +79,7 @@ public class AthenzPrincipalFilterTest {
     }
 
     @Test
-    public void missing_token_is_unauthorized() throws Exception {
+    public void missing_token_and_certificate_is_unauthorized() {
         DiscFilterRequest request = mock(DiscFilterRequest.class);
         when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(null);
 
@@ -70,26 +88,76 @@ public class AthenzPrincipalFilterTest {
         AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
         filter.filter(request, responseHandler);
 
-        assertThat(responseHandler.response, notNullValue());
-        assertThat(responseHandler.response.getStatus(), equalTo(UNAUTHORIZED));
-        assertThat(responseHandler.getResponseContent(), containsString("NToken is missing"));
+        assertUnauthorized(responseHandler, "Unable to authenticate Athenz identity");
+    }
+
+    @Test
+    public void invalid_token_is_unauthorized() {
+        DiscFilterRequest request = mock(DiscFilterRequest.class);
+        String errorMessage = "Invalid token";
+        when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(NTOKEN.getRawToken());
+        when(validator.validate(NTOKEN)).thenThrow(new InvalidTokenException(errorMessage));
+
+        ResponseHandlerMock responseHandler = new ResponseHandlerMock();
+
+        AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
+        filter.filter(request, responseHandler);
+
+        assertUnauthorized(responseHandler, errorMessage);
+    }
+
+    @Test
+    public void certificate_is_accepted() {
+        DiscFilterRequest request = mock(DiscFilterRequest.class);
+        when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(null);
+        when(request.getAttribute("jdisc.request.X509Certificate")).thenReturn(new X509Certificate[]{CERTIFICATE});
+
+        ResponseHandlerMock responseHandler = new ResponseHandlerMock();
+
+        AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
+        filter.filter(request, responseHandler);
+
+        AthenzPrincipal expectedPrincipal = new AthenzPrincipal(IDENTITY);
+        verify(request).setUserPrincipal(expectedPrincipal);
     }
 
     @Test
-    public void invalid_token_is_unauthorized() throws Exception {
+    public void both_ntoken_and_certificate_is_accepted() {
         DiscFilterRequest request = mock(DiscFilterRequest.class);
+        AthenzPrincipal principalWithToken = new AthenzPrincipal(IDENTITY, NTOKEN);
         when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(NTOKEN.getRawToken());
+        when(request.getAttribute("jdisc.request.X509Certificate")).thenReturn(new X509Certificate[]{CERTIFICATE});
+        when(validator.validate(NTOKEN)).thenReturn(principalWithToken);
+
+        ResponseHandlerMock responseHandler = new ResponseHandlerMock();
+
+        AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
+        filter.filter(request, responseHandler);
 
-        when(validator.validate(NTOKEN)).thenThrow(new InvalidTokenException("Invalid token"));
+        verify(request).setUserPrincipal(principalWithToken);
+    }
+
+    @Test
+    public void conflicting_ntoken_and_certificate_is_unauthorized() {
+        DiscFilterRequest request = mock(DiscFilterRequest.class);
+        AthenzUser conflictingIdentity = AthenzUser.fromUserId(new UserId("mallory"));
+        when(request.getHeader(ATHENZ_PRINCIPAL_HEADER)).thenReturn(NTOKEN.getRawToken());
+        when(request.getAttribute("jdisc.request.X509Certificate"))
+                .thenReturn(new X509Certificate[]{createSelfSignedCertificate(conflictingIdentity)});
+        when(validator.validate(NTOKEN)).thenReturn(new AthenzPrincipal(IDENTITY));
 
         ResponseHandlerMock responseHandler = new ResponseHandlerMock();
 
         AthenzPrincipalFilter filter = new AthenzPrincipalFilter(validator, Runnable::run, ATHENZ_PRINCIPAL_HEADER);
         filter.filter(request, responseHandler);
 
+        assertUnauthorized(responseHandler, "Identity in principal token does not match x509 CN");
+    }
+
+    private static void assertUnauthorized(ResponseHandlerMock responseHandler, String expectedMessageSubstring) {
         assertThat(responseHandler.response, notNullValue());
         assertThat(responseHandler.response.getStatus(), equalTo(UNAUTHORIZED));
-        assertThat(responseHandler.getResponseContent(), containsString("Invalid token"));
+        assertThat(responseHandler.getResponseContent(), containsString(expectedMessageSubstring));
     }
 
     private static class ResponseHandlerMock implements ResponseHandler {
@@ -114,4 +182,24 @@ public class AthenzPrincipalFilterTest {
 
     }
 
+    // TODO Move this to separate athenz module/bundle
+    private static X509Certificate createSelfSignedCertificate(AthenzIdentity identity) {
+        try {
+            KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
+            keyGen.initialize(512);
+            KeyPair keyPair = keyGen.genKeyPair();
+            ContentSigner contentSigner = new JcaContentSignerBuilder("SHA256WithRSA").build(keyPair.getPrivate());
+            X500Name x500Name = new X500Name("CN="+ identity.getFullName());
+            X509v3CertificateBuilder certificateBuilder =
+                    new JcaX509v3CertificateBuilder(
+                            x500Name, BigInteger.ONE, new Date(), Date.from(Instant.now().plus(Duration.ofDays(30))),
+                            x500Name, keyPair.getPublic());
+            return new JcaX509CertificateConverter()
+                    .setProvider(new BouncyCastleProvider())
+                    .getCertificate(certificateBuilder.build(contentSigner));
+        } catch (CertificateException | NoSuchAlgorithmException | OperatorCreationException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
 }