KEYCLOAK-2054 - Allow to configure proxy for auth-server requests in adapters.

Previously the adapter configuration did not support specifying a proxy
for auth-server requests issued via the Apache HTTP Client by Keycloak.
This made it very difficult to connect an Application with Keycloak
that was required to use a proxy.

Introduced new `proxy-url` attribute to the adapter configuration
which makes it possible to configure a proxy to be used for auth-server
requests. Proxy-Host, Proxy-Port and Proxy-Scheme are taken from the
configured proxy URL.
Note that proxies that require authentication are currently not supported.

adapters/oidc/adapter-core/src/main/java/org/keycloak/adapters/HttpClientBuilder.java

@@ -17,9 +17,11 @@
 
 package org.keycloak.adapters;
 
+import org.apache.http.HttpHost;
 import org.apache.http.client.CookieStore;
 import org.apache.http.client.HttpClient;
 import org.apache.http.conn.ClientConnectionManager;
+import org.apache.http.conn.params.ConnRoutePNames;
 import org.apache.http.conn.scheme.PlainSocketFactory;
 import org.apache.http.conn.scheme.Scheme;
 import org.apache.http.conn.scheme.SchemeRegistry;
@@ -34,9 +36,9 @@ import org.apache.http.impl.conn.SingleClientConnManager;
 import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
 import org.apache.http.params.BasicHttpParams;
 import org.apache.http.params.HttpConnectionParams;
-import org.keycloak.representations.adapters.config.AdapterConfig;
 import org.keycloak.common.util.EnvUtil;
 import org.keycloak.common.util.KeystoreUtil;
+import org.keycloak.representations.adapters.config.AdapterConfig;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
@@ -46,6 +48,7 @@ import javax.net.ssl.SSLSocket;
 import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509TrustManager;
 import java.io.IOException;
+import java.net.URI;
 import java.security.KeyStore;
 import java.security.SecureRandom;
 import java.security.cert.CertificateException;
@@ -112,6 +115,7 @@ public class HttpClientBuilder {
     protected TimeUnit socketTimeoutUnits = TimeUnit.MILLISECONDS;
     protected long establishConnectionTimeout = -1;
     protected TimeUnit establishConnectionTimeoutUnits = TimeUnit.MILLISECONDS;
+    protected HttpHost proxyHost;
 
 
     /**
@@ -121,8 +125,7 @@ public class HttpClientBuilder {
      * @param unit
      * @return
      */
-    public HttpClientBuilder socketTimeout(long timeout, TimeUnit unit)
-    {
+    public HttpClientBuilder socketTimeout(long timeout, TimeUnit unit) {
         this.socketTimeout = timeout;
         this.socketTimeoutUnits = unit;
         return this;
@@ -135,8 +138,7 @@ public class HttpClientBuilder {
      * @param unit
      * @return
      */
-    public HttpClientBuilder establishConnectionTimeout(long timeout, TimeUnit unit)
-    {
+    public HttpClientBuilder establishConnectionTimeout(long timeout, TimeUnit unit) {
         this.establishConnectionTimeout = timeout;
         this.establishConnectionTimeoutUnits = unit;
         return this;
@@ -287,16 +289,20 @@ public class HttpClientBuilder {
                 cm = new SingleClientConnManager(registry);
             }
             BasicHttpParams params = new BasicHttpParams();
-            if (socketTimeout > -1)
-            {
+
+            if (proxyHost != null) {
+                params.setParameter(ConnRoutePNames.DEFAULT_PROXY, proxyHost);
+            }
+
+            if (socketTimeout > -1) {
                 HttpConnectionParams.setSoTimeout(params, (int) socketTimeoutUnits.toMillis(socketTimeout));
 
             }
-            if (establishConnectionTimeout > -1)
-            {
-                HttpConnectionParams.setConnectionTimeout(params, (int)establishConnectionTimeoutUnits.toMillis(establishConnectionTimeout));
+            if (establishConnectionTimeout > -1) {
+                HttpConnectionParams.setConnectionTimeout(params, (int) establishConnectionTimeoutUnits.toMillis(establishConnectionTimeout));
             }
             DefaultHttpClient client = new DefaultHttpClient(cm, params);
+
             if (disableCookieCache) {
                 client.setCookieStore(new CookieStore() {
                     @Override
@@ -364,6 +370,28 @@ public class HttpClientBuilder {
         } else {
             trustStore(truststore);
         }
+
+        configureProxyForAuthServerIfProvided(adapterConfig);
+
         return build();
     }
+
+    /**
+     * Configures a the proxy to use for auth-server requests if provided.
+     * <p>
+     * If the given {@link AdapterConfig} contains the attribute {@code proxy-url} we use the
+     * given URL as a proxy server, otherwise the proxy configuration is ignored.
+     * </p>
+     *
+     * @param adapterConfig
+     */
+    private void configureProxyForAuthServerIfProvided(AdapterConfig adapterConfig) {
+
+        if (adapterConfig == null || adapterConfig.getProxyUrl() == null || adapterConfig.getProxyUrl().trim().isEmpty()) {
+            return;
+        }
+
+        URI uri = URI.create(adapterConfig.getProxyUrl());
+        this.proxyHost = new HttpHost(uri.getHost(), uri.getPort(), uri.getScheme());
+    }
 }

core/src/main/java/org/keycloak/representations/adapters/config/AdapterConfig.java

@@ -35,7 +35,8 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
         "allow-any-hostname", "disable-trust-manager", "truststore", "truststore-password",
         "client-keystore", "client-keystore-password", "client-key-password",
         "always-refresh-token",
-        "register-node-at-startup", "register-node-period", "token-store", "principal-attribute"
+        "register-node-at-startup", "register-node-period", "token-store", "principal-attribute",
+        "proxy-url"
 })
 public class AdapterConfig extends BaseAdapterConfig {
 
@@ -68,6 +69,12 @@ public class AdapterConfig extends BaseAdapterConfig {
     @JsonProperty("turn-off-change-session-id-on-login")
     protected Boolean turnOffChangeSessionIdOnLogin;
 
+    /**
+     * The Proxy url to use for requests to the auth-server, configurable via the adapter config property {@code proxy-url}.
+     */
+    @JsonProperty("proxy-url")
+    protected String proxyUrl;
+
     public boolean isAllowAnyHostname() {
         return allowAnyHostname;
     }
@@ -179,4 +186,12 @@ public class AdapterConfig extends BaseAdapterConfig {
     public void setTurnOffChangeSessionIdOnLogin(Boolean turnOffChangeSessionIdOnLogin) {
         this.turnOffChangeSessionIdOnLogin = turnOffChangeSessionIdOnLogin;
     }
+
+    public String getProxyUrl() {
+        return proxyUrl;
+    }
+
+    public void setProxyUrl(String proxyUrl) {
+        this.proxyUrl = proxyUrl;
+    }
 }

docbook/auth-server-docs/reference/en/en-US/modules/adapter-config.xml

@@ -405,6 +405,17 @@
                     </para>
                 </listitem>
             </varlistentry>
+            <varlistentry>
+                <term>proxy-url</term>
+                <listitem>
+                    <para>
+                        Defines the proxy to use for requests sent to the auth-server-url.
+                        This is <emphasis>OPTIONAL</emphasis>. Note that only the <emphasis>scheme</emphasis>,
+                        <emphasis>host</emphasis> and <emphasis>port</emphasis> of the proxy URL are used.
+                        Proxies that require authentication are currently not supported.
+                    </para>
+                </listitem>
+            </varlistentry>
         </variablelist>
     </para>
 </section>