Fix NPE ExpressionBasedPreInvocationAdviceTests

Getting NPE if @PreFilter argument filterType is not provided
and method accept more then one argument.

Add related exception message.

fixes gh-6803

core/src/main/java/org/springframework/security/access/expression/method/ExpressionBasedPreInvocationAdvice.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -81,6 +81,9 @@ public class ExpressionBasedPreInvocationAdvice implements
 						"A PreFilter expression was set but the method argument type"
 								+ arg.getClass() + " is not filterable");
 			}
+		} else if (mi.getArguments().length > 1) {
+			throw new IllegalArgumentException(
+					"Unable to determine the method argument for filtering. Specify the filter target.");
 		}
 
 		if (filterTarget.getClass().isArray()) {

core/src/test/java/org/springframework/security/access/expression/method/ExpressionBasedPreInvocationAdviceTests.java

@@ -0,0 +1,162 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.security.access.expression.method;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+import org.springframework.security.access.intercept.method.MockMethodInvocation;
+import org.springframework.security.access.prepost.PreInvocationAttribute;
+import org.springframework.security.core.Authentication;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests {@link ExpressionBasedPreInvocationAdvice}
+ *
+ * @author Maksim Vinogradov
+ * @since 5.2
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ExpressionBasedPreInvocationAdviceTests {
+
+	@Mock
+	private Authentication authentication;
+
+	private ExpressionBasedPreInvocationAdvice expressionBasedPreInvocationAdvice;
+
+	@Before
+	public void setUp() throws Exception {
+		expressionBasedPreInvocationAdvice = new ExpressionBasedPreInvocationAdvice();
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void findFilterTargetNameProvidedButNotMatch() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true",
+																				"filterTargetDoesNotMatch",
+																				null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingCollection",
+																		new Class[]{List.class},
+																		new Object[]{new ArrayList<>()});
+		//when - then
+		expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void findFilterTargetNameProvidedArrayUnsupported() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true",
+																					"param", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingArray",
+																		new Class[]{String[].class},
+																		new Object[]{new String[0]});
+		//when - then
+		expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+	}
+
+	@Test
+	public void findFilterTargetNameProvided() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true", "param", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingCollection",
+																		new Class[]{List.class},
+																		new Object[]{new ArrayList<>()});
+
+		//when
+		boolean result = expressionBasedPreInvocationAdvice
+				.before(authentication, methodInvocation, attribute);
+		//then
+		assertThat(result).isTrue();
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void findFilterTargetNameNotProvidedArrayUnsupported() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true", "", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingArray",
+																		new Class[]{String[].class},
+																		new Object[]{new String[0]});
+		//when - then
+		expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+	}
+
+	@Test
+	public void findFilterTargetNameNotProvided() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true", "", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingCollection",
+																		new Class[]{List.class},
+																		new Object[]{new ArrayList<>()});
+		//when
+		boolean result = expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+		//then
+		assertThat(result).isTrue();
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void findFilterTargetNameNotProvidedTypeNotSupported() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true", "", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingString",
+																		new Class[]{String.class},
+																		new Object[]{"param"});
+		//when - then
+		expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void findFilterTargetNameNotProvidedMethodAcceptMoreThenOneArgument() throws Exception {
+		//given
+		PreInvocationAttribute attribute = new PreInvocationExpressionAttribute("true", "", null);
+		MockMethodInvocation methodInvocation = new MockMethodInvocation(new TestClass(), TestClass.class,
+																		"doSomethingTwoArgs",
+																		new Class[]{String.class, List.class},
+																		new Object[]{"param", new ArrayList<>()});
+		//when - then
+		expressionBasedPreInvocationAdvice.before(authentication, methodInvocation, attribute);
+	}
+
+	private class TestClass {
+
+		public Boolean doSomethingCollection(List<?> param) {
+			return Boolean.TRUE;
+		}
+
+		public Boolean doSomethingArray(String[] param) {
+			return Boolean.TRUE;
+		}
+
+		public Boolean doSomethingString(String param) {
+			return Boolean.TRUE;
+		}
+
+		public Boolean doSomethingTwoArgs(String param, List<?> list) {
+			return Boolean.TRUE;
+		}
+	}
+}

core/src/test/java/org/springframework/security/access/intercept/method/MockMethodInvocation.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,15 +15,22 @@
  */
 package org.springframework.security.access.intercept.method;
 
+import org.aopalliance.intercept.MethodInvocation;
+
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Method;
 
-import org.aopalliance.intercept.MethodInvocation;
-
 @SuppressWarnings("unchecked")
 public class MockMethodInvocation implements MethodInvocation {
 	private Method method;
 	private Object targetObject;
+	private Object[] arguments = new Object[0];
+
+	public MockMethodInvocation(Object targetObject, Class clazz, String methodName, Class[] parameterTypes,
+								Object[] arguments) throws NoSuchMethodException {
+		this(targetObject, clazz, methodName, parameterTypes);
+		this.arguments = arguments;
+	}
 
 	public MockMethodInvocation(Object targetObject, Class clazz, String methodName,
 			Class... parameterTypes) throws NoSuchMethodException {
@@ -32,7 +39,7 @@ public class MockMethodInvocation implements MethodInvocation {
 	}
 
 	public Object[] getArguments() {
-		return null;
+		return arguments;
 	}
 
 	public Method getMethod() {