feat: Support z/OSMF scheme in Spring Cloud Gateway

cloud-gateway-service/build.gradle

@@ -96,7 +96,6 @@ dependencies {
     testImplementation libs.rest.assured
     testImplementation libs.reactorTest
     testImplementation libs.mockito.inline
-
 }
 
 bootJar {

cloud-gateway-service/src/main/java/org/zowe/apiml/cloudgatewayservice/filters/AbstractAuthSchemeFactory.java

@@ -0,0 +1,314 @@
+/*
+ * This program and the accompanying materials are made available under the terms of the
+ * Eclipse Public License v2.0 which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-v20.html
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Copyright Contributors to the Zowe Project.
+ */
+
+package org.zowe.apiml.cloudgatewayservice.filters;
+
+import lombok.Data;
+import org.apache.commons.lang3.StringUtils;
+import org.springframework.cloud.client.ServiceInstance;
+import org.springframework.cloud.gateway.filter.GatewayFilter;
+import org.springframework.cloud.gateway.filter.GatewayFilterChain;
+import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.client.WebClientResponseException;
+import org.springframework.web.server.ServerWebExchange;
+import org.zowe.apiml.cloudgatewayservice.service.InstanceInfoService;
+import org.zowe.apiml.constants.ApimlConstants;
+import org.zowe.apiml.message.core.MessageService;
+import reactor.core.publisher.Mono;
+
+import java.net.HttpCookie;
+import java.util.*;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static org.zowe.apiml.constants.ApimlConstants.PAT_COOKIE_AUTH_NAME;
+import static org.zowe.apiml.constants.ApimlConstants.PAT_HEADER_NAME;
+import static org.zowe.apiml.security.SecurityUtils.COOKIE_AUTH_NAME;
+
+/**
+ * This class is responsible for the shared part about decoration of user request with authentication scheme. The
+ * service defines its own authentication scheme, and it could evaluate a request mutation. The aim is to have as
+ * small implementation as possible. Therefore, the implemntation itself should construct the request to ZAAS with
+ * a minimal requirements and process the result. The rest (common values for ZAAS, retrying, HA evaluation and
+ * sanitation of user request should be done by this class).
+ *
+ * To prepare a new implementation of authentication scheme decoration is required to implement those methods:
+ * - {@link AbstractAuthSchemeFactory#getResponseClass()} - define class of the response body (see T)
+ * - {@link AbstractAuthSchemeFactory#getResponseFor401()} - construct empty response body for 401 response
+ * - {@link AbstractAuthSchemeFactory#createRequest(AbstractConfig, ServerHttpRequest.Builder, ServiceInstance, Object)}
+ *   - create the base part of request to the ZAAS. It requires only related request properties to the releated scheme
+ * - {@link AbstractAuthSchemeFactory#processResponse(ServerWebExchange, GatewayFilterChain, Object)}
+ *   - it is responsible for reading the response from the ZAAS and modifying the clients request to provide new credentials
+ *
+ * Example:
+ *  class MyScheme extends AbstractAuthSchemeFactory<MyScheme.Config, MyResponse, MyData> {
+ *
+ *     @Override
+ *     public GatewayFilter apply(Config config) {
+ *         try {
+ *             return createGatewayFilter(config, <construct common data or null>);
+ *         } catch (Exception e) {
+ *             return ((exchange, chain) -> {
+ *                 ServerHttpRequest request = updateHeadersForError(exchange, e.getMessage());
+ *                 return chain.filter(exchange.mutate().request(request).build());
+ *             });
+ *         }
+ *     }
+ *
+ *     @Override
+ *     protected Class<MyResponse> getResponseClass() {
+ *         return MyResponse.class;
+ *     }
+ *
+ *     @Override
+ *     protected MyResponse getResponseFor401() {
+ *         return new MyResponse();
+ *     }
+ *
+ *     @Override
+ *     protected WebClient.RequestHeadersSpec<?> createRequest(ServiceInstance instance, Object data) {
+ *         String url = String.format("%s://%s:%d/%s/zaas/myScheme", instance.getScheme(), instance.getHost(), instance.getPort(), instance.getServiceId().toLowerCase());
+ *         return webClient.post()
+ *             .uri(url);
+ *     }
+ *
+ *     @Override
+ *     protected Mono<Void> processResponse(ServerWebExchange exchange, GatewayFilterChain chain, MyResponse response) {
+ *         ServerHttpRequest request;
+ *         if (response.getToken() != null) {
+ *             request = exchange.getRequest().mutate().headers(headers ->
+ *                 headers.add("mySchemeHeader", response.getToken())
+ *             ).build();
+ *         } else {
+ *             request = updateHeadersForError(exchange, "Invalid or missing authentication.");
+ *         }
+ *
+ *         exchange = exchange.mutate().request(request).build();
+ *         return chain.filter(exchange);
+ *     }
+ *
+ *     @EqualsAndHashCode(callSuper = true)
+ *     public static class Config extends AbstractAuthSchemeFactory.AbstractConfig {
+ *
+ *     }
+ *
+ *  }
+ *
+ *  @Data
+ *  class MyResponse {
+ *
+ *      private String token;
+ *
+ *  }
+ *
+ * @param <T> Class of config class. It should extend {@link AbstractAuthSchemeFactory.AbstractConfig}
+ * @param <R> Class of expended response from the ZAAS
+ * @param <D> Type of data object that could be constructed before any request, and it is request for creating a request
+ */
+public abstract class AbstractAuthSchemeFactory<T extends AbstractAuthSchemeFactory.AbstractConfig, R, D> extends AbstractGatewayFilterFactory<T> {
+
+    private static final String HEADER_SERVICE_ID = "X-Service-Id";
+
+    private static final Predicate<HttpCookie> CREDENTIALS_COOKIE_INPUT = cookie ->
+        StringUtils.equalsIgnoreCase(cookie.getName(), PAT_COOKIE_AUTH_NAME) ||
+        StringUtils.equalsIgnoreCase(cookie.getName(), COOKIE_AUTH_NAME) ||
+        StringUtils.startsWithIgnoreCase(cookie.getName(), COOKIE_AUTH_NAME + ".");
+    private static final Predicate<HttpCookie> CREDENTIALS_COOKIE = cookie ->
+        CREDENTIALS_COOKIE_INPUT.test(cookie) ||
+        StringUtils.equalsIgnoreCase(cookie.getName(), "jwtToken") ||
+        StringUtils.equalsIgnoreCase(cookie.getName(), "LtpaToken2");
+
+    private static final Predicate<String> CREDENTIALS_HEADER_INPUT = headerName ->
+        StringUtils.equalsIgnoreCase(headerName, HttpHeaders.AUTHORIZATION) ||
+        StringUtils.equalsIgnoreCase(headerName, PAT_HEADER_NAME);
+    private static final Predicate<String> CREDENTIALS_HEADER = headerName ->
+        CREDENTIALS_HEADER_INPUT.test(headerName) ||
+        StringUtils.equalsIgnoreCase(headerName, "X-SAF-Token") ||
+        StringUtils.equalsIgnoreCase(headerName, "X-Certificate-Public") ||
+        StringUtils.equalsIgnoreCase(headerName, "X-Certificate-DistinguishedName") ||
+        StringUtils.equalsIgnoreCase(headerName, "X-Certificate-CommonName") ||
+        StringUtils.equalsIgnoreCase(headerName, HttpHeaders.COOKIE);
+
+    private static final RobinRoundIterator<ServiceInstance> robinRound = new RobinRoundIterator<>();
+
+    protected final WebClient webClient;
+    protected final InstanceInfoService instanceInfoService;
+    protected final MessageService messageService;
+
+    protected AbstractAuthSchemeFactory(Class<T> configClazz, WebClient webClient, InstanceInfoService instanceInfoService, MessageService messageService) {
+        super(configClazz);
+        this.webClient = webClient;
+        this.instanceInfoService = instanceInfoService;
+        this.messageService = messageService;
+    }
+
+    /**
+     * @return class of response body from ZAAS
+     */
+    protected abstract Class<R> getResponseClass();
+
+    /**
+     * @return empty object that is returned in the case of 401 response from ZAAS
+     */
+    protected abstract R getResponseFor401();
+
+    private Mono<List<ServiceInstance>> getZaasInstances() {
+        return instanceInfoService.getServiceInstance("gateway");
+    }
+
+    private Mono<R> requestWithHa(
+        Iterator<ServiceInstance> serviceInstanceIterator,
+        Function<ServiceInstance, WebClient.RequestHeadersSpec<?>> requestCreator
+    ) {
+        return requestCreator.apply(serviceInstanceIterator.next())
+            .retrieve()
+            .onStatus(HttpStatus::is5xxServerError, clientResponse -> Mono.empty())
+            .bodyToMono(getResponseClass())
+            .onErrorResume(exception -> exception instanceof WebClientResponseException.Unauthorized ? Mono.just(getResponseFor401()) : Mono.error(exception))
+            .switchIfEmpty(serviceInstanceIterator.hasNext() ?
+                requestWithHa(serviceInstanceIterator, requestCreator) : Mono.empty()
+            );
+    }
+
+    protected Mono<Void> invoke(
+        List<ServiceInstance> serviceInstances,
+        Function<ServiceInstance, WebClient.RequestHeadersSpec<?>> requestCreator,
+        Function<? super R, ? extends Mono<Void>> responseProcessor
+    ) {
+        Iterator<ServiceInstance> i = robinRound.getIterator(serviceInstances);
+        if (!i.hasNext()) {
+            throw new IllegalArgumentException("No ZAAS is available");
+        }
+
+        return requestWithHa(i, requestCreator).flatMap(responseProcessor);
+    }
+
+    /**
+     * This method should construct basic request to the ZAAS (related to the authentication scheme). It should define
+     * URL, body and specific headers / cookies (if they are needed). The rest of values are set by
+     * {@link AbstractAuthSchemeFactory}
+     *
+     * @param instance - instance of the ZAAS instance that will be invoked
+     * @param data - data object set in the call of {@link AbstractAuthSchemeFactory#createGatewayFilter(AbstractConfig, Object)}
+     * @return builder of the request
+     */
+    @SuppressWarnings({
+        "squid:S1452",  // the internal API cannot define generic more specificly
+        "squid:S2092"   // the cookie is used just for internal purposes (off the browser)
+    })
+    protected abstract WebClient.RequestHeadersSpec<?> createRequest(ServiceInstance instance, D data);
+
+    /**
+     * The method responsible for reading a response from a ZAAS component and decorating of user request (ie. set
+     * credentials as header, etc.)
+     * @param clientCallBuilder builder of customer request (to set new credentials)
+     * @param chain chain of filter to be evaluated. Method should return `return chain.filter(exchange)`
+     * @param response response body from the ZAAS containing new credentials or and empty object - see {@link AbstractAuthSchemeFactory#getResponseFor401()}
+     * @return response of chain evaluation (`return chain.filter(exchange)`)
+     */
+    @SuppressWarnings("squid:S2092")    // the cookie is used just for internal purposes (off the browser)
+    protected abstract Mono<Void> processResponse(ServerWebExchange clientCallBuilder, GatewayFilterChain chain, R response);
+
+    @SuppressWarnings("squid:S1452")    // the internal API cannot define generic more specifically
+    protected WebClient.RequestHeadersSpec<?> createRequest(AbstractConfig config, ServerHttpRequest.Builder clientRequestbuilder, ServiceInstance instance, D data) {
+        WebClient.RequestHeadersSpec<?> zaasCallBuilder = createRequest(instance, data);
+
+        clientRequestbuilder
+            .headers(headers -> {
+                // get all current cookies
+                List<HttpCookie> cookies = readCookies(headers).collect(Collectors.toList());
+
+                // set in the request to ZAAS all cookies and headers that contain credentials
+                headers.entrySet().stream()
+                    .filter(e -> CREDENTIALS_HEADER_INPUT.test(e.getKey()))
+                    .forEach(e -> zaasCallBuilder.header(e.getKey(), e.getValue().toArray(new String[0])));
+                cookies.stream()
+                    .filter(CREDENTIALS_COOKIE_INPUT)
+                    .forEach(c -> zaasCallBuilder.cookie(c.getName(), c.getValue()));
+
+                // add common headers to ZAAS
+                zaasCallBuilder.header(HEADER_SERVICE_ID, config.serviceId);
+
+                // update original request - to remove all potential headers and cookies with credentials
+                Stream<Map.Entry<String, String>> nonCredentialHeaders = headers.entrySet().stream()
+                    .filter(entry -> !CREDENTIALS_HEADER.test(entry.getKey()))
+                    .flatMap(entry -> entry.getValue().stream().map(v -> new AbstractMap.SimpleEntry<>(entry.getKey(), v)));
+                Stream<Map.Entry<String, String>> nonCredentialCookies = cookies.stream()
+                    .filter(c -> !CREDENTIALS_COOKIE.test(c))
+                    .map(c -> new AbstractMap.SimpleEntry<>(HttpHeaders.COOKIE, c.toString()));
+
+                List<Map.Entry<String, String>> newHeaders = Stream.concat(
+                    nonCredentialHeaders,
+                    nonCredentialCookies
+                ).collect(Collectors.toList());
+
+                headers.clear();
+                newHeaders.forEach(newHeader -> headers.add(newHeader.getKey(), newHeader.getValue()));
+            });
+
+        return zaasCallBuilder;
+    }
+
+    protected GatewayFilter createGatewayFilter(AbstractConfig config, D data) {
+        return (exchange, chain) -> getZaasInstances().flatMap(
+            instances -> {
+                ServerHttpRequest.Builder clientCallBuilder = exchange.getRequest().mutate();
+                return invoke(
+                    instances,
+                    instance -> createRequest(config, clientCallBuilder, instance, data),
+                    response -> processResponse(exchange.mutate().request(clientCallBuilder.build()).build(), chain, response)
+                );
+            }
+        );
+    }
+    protected ServerHttpRequest addRequestHeader(ServerWebExchange exchange, String key, String value) {
+        return exchange.getRequest().mutate()
+            .headers(headers -> headers.add(key, value))
+            .build();
+    }
+
+    protected ServerHttpRequest setRequestHeader(ServerWebExchange exchange, String headerName, String headerValue) {
+        return exchange.getRequest().mutate()
+            .header(headerName, headerValue)
+            .build();
+    }
+
+    protected ServerHttpRequest updateHeadersForError(ServerWebExchange exchange, String errorMessage) {
+        ServerHttpRequest request = addRequestHeader(exchange, ApimlConstants.AUTH_FAIL_HEADER, messageService.createMessage("org.zowe.apiml.security.ticket.generateFailed", errorMessage).mapToLogMessage());
+        exchange.getResponse().getHeaders().add(ApimlConstants.AUTH_FAIL_HEADER, messageService.createMessage("org.zowe.apiml.security.ticket.generateFailed", errorMessage).mapToLogMessage());
+        return request;
+    }
+
+    protected Stream<HttpCookie> readCookies(HttpHeaders httpHeaders) {
+        return Optional.ofNullable(httpHeaders.get(HttpHeaders.COOKIE))
+            .orElse(Collections.emptyList())
+            .stream()
+            .map(v -> StringUtils.split(v, ";"))
+            .flatMap(Arrays::stream)
+            .map(StringUtils::trim)
+            .map(HttpCookie::parse)
+            .flatMap(List::stream);
+    }
+
+    @Data
+    protected abstract static class AbstractConfig {
+
+        // service ID of the target service
+        private String serviceId;
+
+    }
+
+}