feat(auth): Redirect to OpenShift login on empty auth request

src/main/java/io/cryostat/net/AuthManager.java

@@ -37,7 +37,9 @@
  */
 package io.cryostat.net;
 
+import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.function.Function;
 import java.util.function.Supplier;
@@ -49,6 +51,10 @@ public interface AuthManager {
 
     Future<UserInfo> getUserInfo(Supplier<String> httpHeaderProvider);
 
+    Optional<String> getLoginRedirectUrl(
+            Supplier<String> headerProvider, Set<ResourceAction> resourceActions)
+            throws ExecutionException, InterruptedException;
+
     Future<Boolean> validateToken(
             Supplier<String> tokenProvider, Set<ResourceAction> resourceActions);
 

src/main/java/io/cryostat/net/BasicAuthManager.java

@@ -43,6 +43,7 @@
 import java.nio.file.Path;
 import java.util.Base64;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Properties;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
@@ -98,6 +99,12 @@ public Future<UserInfo> getUserInfo(Supplier<String> httpHeaderProvider) {
         return CompletableFuture.completedFuture(new UserInfo(user));
     }
 
+    @Override
+    public Optional<String> getLoginRedirectUrl(
+            Supplier<String> headerProvider, Set<ResourceAction> resourceActions) {
+        return Optional.empty();
+    }
+
     @Override
     public Future<Boolean> validateToken(
             Supplier<String> tokenProvider, Set<ResourceAction> resourceActions) {
@@ -159,6 +166,9 @@ public Future<Boolean> validateWebSocketSubProtocol(
     }
 
     private Pair<String, String> splitCredentials(String credentials) {
+        if (credentials == null) {
+            return null;
+        }
         Pattern credentialsPattern = Pattern.compile("([\\S]+):([\\S]+)");
         Matcher matcher = credentialsPattern.matcher(credentials);
         if (!matcher.matches()) {

src/main/java/io/cryostat/net/MissingEnvironmentVariableException.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright The Cryostat Authors
+ *
+ * The Universal Permissive License (UPL), Version 1.0
+ *
+ * Subject to the condition set forth below, permission is hereby granted to any
+ * person obtaining a copy of this software, associated documentation and/or data
+ * (collectively the "Software"), free of charge and under any and all copyright
+ * rights in the Software, and any and all patent rights owned or freely
+ * licensable by each licensor hereunder covering either (i) the unmodified
+ * Software as contributed to or provided by such licensor, or (ii) the Larger
+ * Works (as defined below), to deal in both
+ *
+ * (a) the Software, and
+ * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
+ * one is included with the Software (each a "Larger Work" to which the Software
+ * is contributed by such licensors),
+ *
+ * without restriction, including without limitation the rights to copy, create
+ * derivative works of, display, perform, and distribute the Software and make,
+ * use, sell, offer for sale, import, export, have made, and have sold the
+ * Software and the Larger Work(s), and to sublicense the foregoing rights on
+ * either these or other terms.
+ *
+ * This license is subject to the following condition:
+ * The above copyright notice and either this complete permission notice or at
+ * a minimum a reference to the UPL must be included in all copies or
+ * substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+package io.cryostat.net;
+
+public class MissingEnvironmentVariableException extends Exception {
+    public MissingEnvironmentVariableException(String key) {
+        super(String.format("Missing required environment variable: \"%s\"", key));
+    }
+}

src/main/java/io/cryostat/net/NetworkModule.java

@@ -197,13 +197,16 @@ static BasicAuthManager provideBasicAuthManager(
 
     @Provides
     @Singleton
-    static OpenShiftAuthManager provideOpenShiftAuthManager(Logger logger, FileSystem fs) {
+    static OpenShiftAuthManager provideOpenShiftAuthManager(
+            Environment env, Logger logger, FileSystem fs, WebClient webClient) {
         return new OpenShiftAuthManager(
+                env,
                 logger,
                 fs,
                 token ->
                         new DefaultOpenShiftClient(
-                                new OpenShiftConfigBuilder().withOauthToken(token).build()));
+                                new OpenShiftConfigBuilder().withOauthToken(token).build()),
+                webClient);
     }
 
     @Binds

src/main/java/io/cryostat/net/NoopAuthManager.java

@@ -37,6 +37,7 @@
  */
 package io.cryostat.net;
 
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Future;
@@ -61,6 +62,12 @@ public Future<UserInfo> getUserInfo(Supplier<String> httpHeaderProvider) {
         return CompletableFuture.completedFuture(new UserInfo(""));
     }
 
+    @Override
+    public Optional<String> getLoginRedirectUrl(
+            Supplier<String> headerProvider, Set<ResourceAction> resourceActions) {
+        return Optional.empty();
+    }
+
     @Override
     public Future<Boolean> validateToken(
             Supplier<String> tokenProvider, Set<ResourceAction> resourceActions) {

src/main/java/io/cryostat/net/OpenShiftAuthManager.java

@@ -38,12 +38,16 @@
 package io.cryostat.net;
 
 import java.io.IOException;
+import java.net.URISyntaxException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Paths;
 import java.util.Base64;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -55,6 +59,7 @@
 import java.util.stream.Stream;
 
 import io.cryostat.core.log.Logger;
+import io.cryostat.core.sys.Environment;
 import io.cryostat.core.sys.FileSystem;
 import io.cryostat.net.security.ResourceAction;
 import io.cryostat.net.security.ResourceType;
@@ -69,25 +74,43 @@
 import io.fabric8.kubernetes.client.Config;
 import io.fabric8.kubernetes.client.KubernetesClientException;
 import io.fabric8.openshift.client.OpenShiftClient;
+import io.vertx.core.json.JsonObject;
+import io.vertx.ext.web.client.WebClient;
 import jdk.jfr.Category;
 import jdk.jfr.Event;
 import jdk.jfr.Label;
 import jdk.jfr.Name;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.http.client.utils.URIBuilder;
 
 public class OpenShiftAuthManager extends AbstractAuthManager {
 
     private static final Set<GroupResource> PERMISSION_NOT_REQUIRED =
             Set.of(GroupResource.PERMISSION_NOT_REQUIRED);
+    private static final String OAUTH_WELL_KNOWN_HOST = "openshift.default.svc";
+    private static final String WELL_KNOWN_PATH = "/.well-known/oauth-authorization-server";
+    private static final String OAUTH_ENDPOINT_KEY = "authorization_endpoint";
+    private static final String CRYOSTAT_OAUTH_CLIENT_ID = "CRYOSTAT_OAUTH_CLIENT_ID";
+    private static final String CRYOSTAT_OAUTH_ROLE = "CRYOSTAT_OAUTH_ROLE";
 
+    private final Environment env;
     private final FileSystem fs;
     private final Function<String, OpenShiftClient> clientProvider;
+    private final WebClient webClient;
+    private final ConcurrentHashMap<String, CompletableFuture<String>> authorizationUrl;
 
     OpenShiftAuthManager(
-            Logger logger, FileSystem fs, Function<String, OpenShiftClient> clientProvider) {
+            Environment env,
+            Logger logger,
+            FileSystem fs,
+            Function<String, OpenShiftClient> clientProvider,
+            WebClient webClient) {
         super(logger);
+        this.env = env;
         this.fs = fs;
         this.clientProvider = clientProvider;
+        this.webClient = webClient;
+        this.authorizationUrl = new ConcurrentHashMap<>(1);
     }
 
     @Override
@@ -113,6 +136,29 @@ public Future<UserInfo> getUserInfo(Supplier<String> httpHeaderProvider) {
         }
     }
 
+    @Override
+    public Optional<String> getLoginRedirectUrl(
+            Supplier<String> headerProvider, Set<ResourceAction> resourceActions)
+            throws ExecutionException, InterruptedException {
+        Boolean hasValidHeader = false;
+        try {
+            hasValidHeader = this.validateHttpHeader(headerProvider, resourceActions).get();
+
+            if (Boolean.TRUE.equals(hasValidHeader)) {
+                return Optional.empty();
+            }
+            return Optional.of(this.computeAuthorizationEndpoint().get());
+        } catch (ExecutionException ee) {
+            Throwable cause = ee.getCause();
+            if (cause instanceof PermissionDeniedException
+                    || cause instanceof AuthorizationErrorException
+                    || cause instanceof KubernetesClientException) {
+                return Optional.of(this.computeAuthorizationEndpoint().get());
+            }
+            throw ee;
+        }
+    }
+
     @Override
     public Future<Boolean> validateToken(
             Supplier<String> tokenProvider, Set<ResourceAction> resourceActions) {
@@ -287,6 +333,68 @@ private Future<TokenReviewStatus> performTokenReview(String token) {
         }
     }
 
+    private CompletableFuture<String> computeAuthorizationEndpoint() {
+        return authorizationUrl.computeIfAbsent(
+                OAUTH_ENDPOINT_KEY,
+                key -> {
+                    CompletableFuture<JsonObject> oauthMetadata = new CompletableFuture<>();
+                    try {
+                        String namespace = this.getNamespace();
+                        Optional<String> clientId =
+                                Optional.ofNullable(env.getEnv(CRYOSTAT_OAUTH_CLIENT_ID));
+                        Optional<String> roleScope =
+                                Optional.ofNullable(env.getEnv(CRYOSTAT_OAUTH_ROLE));
+
+                        String serviceAccountAsOAuthClient =
+                                String.format(
+                                        "system:serviceaccount:%s:%s",
+                                        namespace,
+                                        clientId.orElseThrow(
+                                                () ->
+                                                        new MissingEnvironmentVariableException(
+                                                                CRYOSTAT_OAUTH_CLIENT_ID)));
+
+                        String scope =
+                                String.format(
+                                        "user:check-access role:%s:%s",
+                                        roleScope.orElseThrow(
+                                                () ->
+                                                        new MissingEnvironmentVariableException(
+                                                                CRYOSTAT_OAUTH_ROLE)),
+                                        namespace);
+
+                        webClient
+                                .get(443, OAUTH_WELL_KNOWN_HOST, WELL_KNOWN_PATH)
+                                .putHeader("Accept", "application/json")
+                                .send(
+                                        ar -> {
+                                            if (ar.failed()) {
+                                                oauthMetadata.completeExceptionally(ar.cause());
+                                                return;
+                                            }
+                                            oauthMetadata.complete(ar.result().bodyAsJsonObject());
+                                        });
+
+                        String authorizeEndpoint =
+                                oauthMetadata.get().getString(OAUTH_ENDPOINT_KEY);
+
+                        URIBuilder builder = new URIBuilder(authorizeEndpoint);
+                        builder.addParameter("client_id", serviceAccountAsOAuthClient);
+                        builder.addParameter("response_type", "token");
+                        builder.addParameter("response_mode", "fragment");
+                        builder.addParameter("scope", scope);
+
+                        return CompletableFuture.completedFuture(builder.build().toString());
+                    } catch (ExecutionException
+                            | InterruptedException
+                            | URISyntaxException
+                            | IOException
+                            | MissingEnvironmentVariableException e) {
+                        throw new CompletionException(e);
+                    }
+                });
+    }
+
     @SuppressFBWarnings(
             value = "DMI_HARDCODED_ABSOLUTE_FILENAME",
             justification = "Kubernetes namespace file path is well-known and absolute")

src/main/java/io/cryostat/net/web/http/api/v2/AuthPostHandler.java

@@ -37,11 +37,14 @@
  */
 package io.cryostat.net.web.http.api.v2;
 
+import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
 
 import javax.inject.Inject;
 
 import io.cryostat.net.AuthManager;
+import io.cryostat.net.UnknownUserException;
 import io.cryostat.net.UserInfo;
 import io.cryostat.net.security.ResourceAction;
 import io.cryostat.net.web.WebServer;
@@ -61,7 +64,7 @@ protected AuthPostHandler(AuthManager auth, Gson gson) {
 
     @Override
     public boolean requiresAuthentication() {
-        return true;
+        return false;
     }
 
     @Override
@@ -96,14 +99,43 @@ public boolean isAsync() {
 
     @Override
     public IntermediateResponse<UserInfo> handle(RequestParameters requestParams) throws Exception {
-        return new IntermediateResponse<UserInfo>()
-                .addHeader(WebServer.AUTH_SCHEME_HEADER, auth.getScheme().toString())
-                .body(
-                        auth.getUserInfo(
-                                        () ->
-                                                requestParams
-                                                        .getHeaders()
-                                                        .get(HttpHeaders.AUTHORIZATION))
-                                .get());
+
+        Optional<String> redirectUrl =
+                auth.getLoginRedirectUrl(
+                        () -> requestParams.getHeaders().get(HttpHeaders.AUTHORIZATION),
+                        resourceActions());
+
+        return redirectUrl
+                .map(
+                        location -> {
+                            return new IntermediateResponse<UserInfo>()
+                                    .addHeader("X-Location", location)
+                                    .addHeader("access-control-expose-headers", "Location")
+                                    .statusCode(302);
+                        })
+                .orElseGet(
+                        () -> {
+                            try {
+                                return new IntermediateResponse<UserInfo>()
+                                        .addHeader(
+                                                WebServer.AUTH_SCHEME_HEADER,
+                                                auth.getScheme().toString())
+                                        .body(
+                                                auth.getUserInfo(
+                                                                () ->
+                                                                        requestParams
+                                                                                .getHeaders()
+                                                                                .get(
+                                                                                        HttpHeaders
+                                                                                                .AUTHORIZATION))
+                                                        .get());
+                            } catch (ExecutionException | InterruptedException ee) {
+                                Throwable cause = ee.getCause();
+                                if (cause instanceof UnknownUserException) {
+                                    throw new ApiException(401, "HTTP Authorization Failure", ee);
+                                }
+                                throw new ApiException(500, ee);
+                            }
+                        });
     }
 }

src/test/java/io/cryostat/net/BasicAuthManagerTest.java

@@ -278,7 +278,7 @@ void shouldFailUnknownCredentials() throws Exception {
         }
 
         @ParameterizedTest
-        @ValueSource(strings = {"", "Bearer sometoken", "Basic (not_b64)"})
+        @ValueSource(strings = {"", "Bearer sometoken", "Basic (not_b64)", "Basic "})
         @NullSource
         void shouldFailBadCredentials(String s) throws Exception {
             Assertions.assertFalse(mgr.validateHttpHeader(() -> s, ResourceAction.NONE).get());