Adds ability to disable hostname validation.

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/ZuulProperties.java

@@ -111,7 +111,7 @@ public class ZuulProperties {
 	private boolean traceRequestBody = true;
 
 	/**
-	 * Flag to say that path elelents past the first semicolon can be dropped.
+	 * Flag to say that path elements past the first semicolon can be dropped.
 	 */
 	private boolean removeSemicolonContent = true;
 
@@ -125,6 +125,12 @@ public class ZuulProperties {
 	private Set<String> sensitiveHeaders = new LinkedHashSet<>(
 			Arrays.asList("Cookie", "Set-Cookie", "Authorization"));
 
+	/**
+	 * Flag to say whether the hostname for ssl connections should be verified or now. Default is true.
+	 * This should only be used in test setups!
+	 */
+	private boolean sslHostnameValidationEnabled =true;
+
 	public Set<String> getIgnoredHeaders() {
 		Set<String> ignoredHeaders = new LinkedHashSet<>(this.ignoredHeaders);
 		if (ClassUtils.isPresent(

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/SimpleHostRoutingFilter.java

@@ -53,11 +53,13 @@ import org.apache.http.config.Registry;
 import org.apache.http.config.RegistryBuilder;
 import org.apache.http.conn.socket.ConnectionSocketFactory;
 import org.apache.http.conn.socket.PlainConnectionSocketFactory;
+import org.apache.http.conn.ssl.NoopHostnameVerifier;
 import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
 import org.apache.http.entity.ContentType;
 import org.apache.http.entity.InputStreamEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.DefaultHttpRequestRetryHandler;
+import org.apache.http.impl.client.HttpClientBuilder;
 import org.apache.http.impl.client.HttpClients;
 import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
 import org.apache.http.message.BasicHeader;
@@ -66,7 +68,6 @@ import org.apache.http.protocol.HttpContext;
 import org.springframework.cloud.netflix.zuul.filters.ProxyRequestHelper;
 import org.springframework.cloud.netflix.zuul.filters.ZuulProperties;
 import org.springframework.cloud.netflix.zuul.filters.ZuulProperties.Host;
-import org.springframework.http.HttpStatus;
 import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.StringUtils;
@@ -94,6 +95,8 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 	private final Timer connectionManagerTimer = new Timer(
 			"SimpleHostRoutingFilter.connectionManagerTimer", true);
 
+	private boolean sslHostnameValidationEnabled;
+
 	private ProxyRequestHelper helper;
 	private Host hostProperties;
 	private PoolingHttpClientConnectionManager connectionManager;
@@ -115,6 +118,7 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 	public SimpleHostRoutingFilter(ProxyRequestHelper helper, ZuulProperties properties) {
 		this.helper = helper;
 		this.hostProperties = properties.getHost();
+		this.sslHostnameValidationEnabled = properties.isSslHostnameValidationEnabled();
 	}
 
 	@PostConstruct
@@ -204,11 +208,18 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 				}
 			} }, new SecureRandom());
 
-			final Registry<ConnectionSocketFactory> registry = RegistryBuilder
+			RegistryBuilder<ConnectionSocketFactory> registryBuilder = RegistryBuilder
 					.<ConnectionSocketFactory> create()
-					.register("http", PlainConnectionSocketFactory.INSTANCE)
-					.register("https", new SSLConnectionSocketFactory(sslContext))
-					.build();
+					.register("http", PlainConnectionSocketFactory.INSTANCE);
+			if (sslHostnameValidationEnabled) {
+				registryBuilder.register("https",
+						new SSLConnectionSocketFactory(sslContext));
+			}
+			else {
+				registryBuilder.register("https", new SSLConnectionSocketFactory(
+						sslContext, NoopHostnameVerifier.INSTANCE));
+			}
+			final Registry<ConnectionSocketFactory> registry = registryBuilder.build();
 
 			this.connectionManager = new PoolingHttpClientConnectionManager(registry);
 			this.connectionManager
@@ -228,7 +239,11 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 				.setConnectTimeout(CONNECTION_TIMEOUT.get())
 				.setCookieSpec(CookieSpecs.IGNORE_COOKIES).build();
 
-		return HttpClients.custom().setConnectionManager(newConnectionManager())
+		HttpClientBuilder httpClientBuilder = HttpClients.custom();
+		if (!sslHostnameValidationEnabled) {
+			httpClientBuilder.setSSLHostnameVerifier(NoopHostnameVerifier.INSTANCE);
+		}
+		return httpClientBuilder.setConnectionManager(newConnectionManager())
 				.setDefaultRequestConfig(requestConfig)
 				.setRetryHandler(new DefaultHttpRequestRetryHandler(0, false))
 				.setRedirectStrategy(new RedirectStrategy() {
@@ -363,4 +378,11 @@ public class SimpleHostRoutingFilter extends ZuulFilter {
 		this.helper.addIgnoredHeaders(names);
 	}
 
+	/**
+	 * Determines whether the filter enables the validation for ssl hostnames.
+	 * @return
+	 */
+	boolean isSslHostnameValidationEnabled() {
+		return sslHostnameValidationEnabled;
+	}
 }

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/SimpleHostRoutingFilterTests.java

@@ -28,6 +28,8 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 import static org.springframework.boot.test.EnvironmentTestUtils.addEnvironment;
 
 /**
@@ -55,6 +57,21 @@ public class SimpleHostRoutingFilterTests {
 	}
 
 	@Test
+	public void validateSslHostnamesByDefault() {
+		setupContext();
+		assertTrue("Hostname verification should be enabled by default",
+				getFilter().isSslHostnameValidationEnabled());
+	}
+
+	@Test
+	public void validationOfSslHostnamesCanBeDisabledViaProperty() {
+		addEnvironment(this.context, "zuul.sslHostnameValidationEnabled=false");
+		setupContext();
+		assertFalse("Hostname verification should be disabled via property",
+				getFilter().isSslHostnameValidationEnabled());
+	}
+
+	@Test
 	public void defaultPropertiesAreApplied() {
 		setupContext();
 		PoolingHttpClientConnectionManager connMgr = getFilter().newConnectionManager();