KEYCLOAK-2479 Avoid ZIPException during bigger load

common/src/main/java/org/keycloak/common/util/Base64Url.java

@@ -49,7 +49,8 @@ public class Base64Url {
                         "Illegal base64url string!");
         }
         try {
-            return Base64.decode(s);
+            // KEYCLOAK-2479 : Avoid to try gzip decoding as for some objects, it may display exception to STDERR. And we know that object wasn't encoded as GZIP
+            return Base64.decode(s, Base64.DONT_GUNZIP);
         } catch (Exception e) {
             throw new RuntimeException(e);
         }

core/src/test/java/org/keycloak/SkeletonKeyTokenTest.java

@@ -126,4 +126,12 @@ public class SkeletonKeyTokenTest {
         token.addAccess("bar").addRole("user");
         return token;
     }
+
+    @Test
+    public void testZipException() throws Exception {
+        // KEYCLOAK-2479
+        // Example of LogoutAction, which shows the exception to STDERR during Base64.decode . Need to use flag DONT_GUNZIP to avoid it.
+        String logoutAction = "eyJhbGciOiJSUzI1NiJ9.eyJpZCI6ImUwYmRmMjQyLWJjZGItNGVjMy1hMGU4LTNjN2YyOTUzOTk5MC0xNDU1NzgyNTU2NjAyIiwiZXhwaXJhdGlvbiI6MTQ1NTc4MjU4NiwicmVzb3VyY2UiOiJwcm9kdWN0LXBvcnRhbCIsImFjdGlvbiI6IkxPR09VVCIsImFkYXB0ZXJTZXNzaW9uSWRzIjpbImx2c0oxNUpSX01XUE13aTIwbWRhTkJFRVZQZzQtMTkzVUZKem42M1EiXSwibm90QmVmb3JlIjowLCJrZXljbG9ha1Nlc3Npb25JZHMiOlsiOThkNWE3YTYtYjNmNi00ZTg3LWI5OTktOTg1N2YzMDRiZjY4Il19.H4vo7YXW8oQgYsIo9VPYeSsp1jXJR0TwJUwmiXjQJSyxFoKhHgIh3Y63ldVUeBRppxX9xhjOdYEckeppAn-1XnNxUmbExXWXirRIw8tiEtUPPCPztdkKsM0y6xWRd3Sjgg4fWB_1sMn6EWvCAvO7ahs6Rbb2Vo18nlHfxYRSTWw";
+        JWSInput input = new JWSInput(logoutAction);
+    }
 }