From 12c3f4129dffdc9a120419cb51dff7f7a511174c Mon Sep 17 00:00:00 2001
From: sbrannen
Date: Tue, 1 Nov 2022 19:58:40 +0800
Subject: [PATCH] Improve diagnostics in SpEL for large array creation
Attempting to create a large array in a SpEL expression can result in
an OutOfMemoryError. Although the JVM recovers from that, the error
message is not very helpful to the user.
 
This commit improves the diagnostics in SpEL for large array creation
by throwing a SpelEvaluationException with a meaningful error message
in order to improve diagnostics for the user.
 
---
 .../expression/spel/SpelMessage.java          | 16 +++++++++++--
 .../spel/ast/ConstructorReference.java        | 24 +++++++++++++++++--
 .../spel/ArrayConstructorTests.java           |  4 ++++
 3 files changed, 40 insertions(+), 4 deletions(-)
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java b/spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java
index 9a42cedb..0cf93915 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -34,6 +34,7 @@ import java.text.MessageFormat;
  * if it is known.
  *
  * @author Andy Clement
+ * @author Sam Brannen
  * @since 3.0
  */
 public enum SpelMessage {
@@ -108,8 +109,19 @@ public enum SpelMessage {
 	NOT_ASSIGNABLE(Kind.ERROR,1068,"the expression component ''{0}'' is not assignable"),
 	MISSING_CHARACTER(Kind.ERROR,1069,"missing expected character ''{0}''"),
 	LEFT_OPERAND_PROBLEM(Kind.ERROR,1070, "Problem parsing left operand"),
-	MISSING_SELECTION_EXPRESSION(Kind.ERROR, 1071, "A required selection expression has not been specified");
+	MISSING_SELECTION_EXPRESSION(Kind.ERROR, 1071, "A required selection expression has not been specified"),
 
+        /** @since 4.1 */
+	EXCEPTION_RUNNING_COMPILED_EXPRESSION(Kind.ERROR, 1072,
+			"An exception occurred whilst evaluating a compiled expression"),
+
+	/** @since 4.3.17 */
+	FLAWED_PATTERN(Kind.ERROR, 1073,
+			"Failed to efficiently evaluate pattern ''{0}'': consider redesigning it"),
+
+	/** @since 5.2.20 */
+	MAX_ARRAY_ELEMENTS_THRESHOLD_EXCEEDED(Kind.ERROR, 1075,
+			"Array declares too many elements, exceeding the threshold of ''{0}''");
 
 	private final Kind kind;
 
diff --git a/spring-expression/src/main/java/org/springframework/expression/spel/ast/ConstructorReference.java b/spring-expression/src/main/java/org/springframework/expression/spel/ast/ConstructorReference.java
index c6a25931..4ede5ac3 100644
--- a/spring-expression/src/main/java/org/springframework/expression/spel/ast/ConstructorReference.java
+++ b/spring-expression/src/main/java/org/springframework/expression/spel/ast/ConstructorReference.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -47,12 +47,20 @@ import org.springframework.expression.spel.SpelNode;
  *
  * @author Andy Clement
  * @author Juergen Hoeller
+ * @author Sam Brannen
  * @since 3.0
  */
 public class ConstructorReference extends SpelNodeImpl {
 
 	private boolean isArrayConstructor = false;
 
+	/**
+	 * Maximum number of elements permitted in an array declaration, applying
+	 * to one-dimensional as well as multi-dimensional arrays.
+	 * @since 5.2.20
+	 */
+	private static final int MAX_ARRAY_ELEMENTS = 256 * 1024; // 256K
+
 	private SpelNodeImpl[] dimensions;
 
 	// TODO is this caching safe - passing the expression around will mean this executor is also being passed around
@@ -247,14 +255,19 @@ public class ConstructorReference extends SpelNodeImpl {
 			if (this.dimensions.length == 1) {
 				TypedValue o = this.dimensions[0].getTypedValue(state);
 				int arraySize = ExpressionUtils.toInt(typeConverter, o);
+				checkNumElements(arraySize);
 				newArray = Array.newInstance(componentType, arraySize);
 			}
 			else {
 				// Multi-dimensional - hold onto your hat!
 				int[] dims = new int[this.dimensions.length];
+				long numElements = 1;
 				for (int d = 0; d < this.dimensions.length; d++) {
 					TypedValue o = this.dimensions[d].getTypedValue(state);
-					dims[d] = ExpressionUtils.toInt(typeConverter, o);
+					int arraySize = ExpressionUtils.toInt(typeConverter, o);
+					dims[d] = arraySize;
+					numElements *= arraySize;
+					checkNumElements(numElements);
 				}
 				newArray = Array.newInstance(componentType, dims);
 			}
@@ -314,6 +327,13 @@ public class ConstructorReference extends SpelNodeImpl {
 		return new TypedValue(newArray);
 	}
 
+	private void checkNumElements(long numElements) {
+		if (numElements >= MAX_ARRAY_ELEMENTS) {
+			throw new SpelEvaluationException(getStartPosition(),
+					SpelMessage.MAX_ARRAY_ELEMENTS_THRESHOLD_EXCEEDED, MAX_ARRAY_ELEMENTS);
+		}
+	}
+
 	private void populateReferenceTypeArray(ExpressionState state, Object newArray, TypeConverter typeConverter,
 			InlineList initializer, Class<?> componentType) {
 		TypeDescriptor toTypeDescriptor = TypeDescriptor.valueOf(componentType);
diff --git a/spring-expression/src/test/java/org/springframework/expression/spel/ArrayConstructorTests.java b/spring-expression/src/test/java/org/springframework/expression/spel/ArrayConstructorTests.java
index 16671155..d1ce52f8 100644
--- a/spring-expression/src/test/java/org/springframework/expression/spel/ArrayConstructorTests.java
+++ b/spring-expression/src/test/java/org/springframework/expression/spel/ArrayConstructorTests.java
@@ -80,6 +80,10 @@ public class ArrayConstructorTests extends ExpressionTestCase {
 		evaluateAndCheckError("new char[3]{'a','c','d','e'}", SpelMessage.INITIALIZER_LENGTH_INCORRECT);
 		evaluateAndCheckError("new char[2]{'hello','world'}", SpelMessage.TYPE_CONVERSION_ERROR);
 		evaluateAndCheckError("new String('a','c','d')", SpelMessage.CONSTRUCTOR_INVOCATION_PROBLEM);
+
+		int threshold = 256 * 1024; // ConstructorReference.MAX_ARRAY_ELEMENTS
+		evaluateAndCheckError("new int[T(java.lang.Integer).MAX_VALUE]", SpelMessage.MAX_ARRAY_ELEMENTS_THRESHOLD_EXCEEDED, 0, threshold);
+		evaluateAndCheckError("new int[1024 * 1024][1024 * 1024]", SpelMessage.MAX_ARRAY_ELEMENTS_THRESHOLD_EXCEEDED, 0, threshold);
 	}
 
 	@Test
-- 
2.27.0
