Make use of PatternMatchUtils ignoreCase option

Closes spring-projectsgh-34801

Author: rstoyanchev

spring-context/src/main/java/org/springframework/validation/DataBinder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 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.
@@ -23,7 +23,6 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
-import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 
@@ -53,18 +52,20 @@
 import org.springframework.util.StringUtils;
 
 /**
- * Binder that allows for setting property values onto a target object,
- * including support for validation and binding result analysis.
- * The binding process can be customized through specifying allowed fields,
+ * Binder that allows for setting property values on a target object, including
+ * support for validation and binding result analysis.
+ *
+ * <p>The binding process can be customized by specifying allowed field patterns,
  * required fields, custom editors, etc.
  *
- * <p>Note that there are potential security implications in failing to set an array
- * of allowed fields. In the case of HTTP form POST data for example, malicious clients
- * can attempt to subvert an application by supplying values for fields or properties
- * that do not exist on the form. In some cases this could lead to illegal data being
- * set on command objects <i>or their nested objects</i>. For this reason, it is
- * <b>highly recommended to specify the {@link #setAllowedFields allowedFields} property</b>
- * on the DataBinder.
+ * <p><strong>WARNING</strong>: Data binding can lead to security issues by exposing
+ * parts of the object graph that are not meant to be accessed or modified by
+ * external clients. Therefore, the design and use of data binding should be considered
+ * carefully with regard to security. For more details, please refer to the dedicated
+ * sections on data binding for
+ * <a href="https://docs.spring.io/spring-framework/docs/current/reference/html/web.html#mvc-ann-initbinder-model-design">Spring Web MVC</a> and
+ * <a href="https://docs.spring.io/spring-framework/docs/current/reference/html/web-reactive.html#webflux-ann-initbinder-model-design">Spring WebFlux</a>
+ * in the reference manual.
  *
  * <p>The binding results can be examined via the {@link BindingResult} interface,
  * extending the {@link Errors} interface: see the {@link #getBindingResult()} method.
@@ -174,7 +175,7 @@ public class DataBinder implements PropertyEditorRegistry, TypeConverter {
 	 * if the binder is just used to convert a plain parameter value)
 	 * @see #DEFAULT_OBJECT_NAME
 	 */
-	public DataBinder(Object target) {
+    public DataBinder(Object target) {
 		this(target, DEFAULT_OBJECT_NAME);
 	}
 
@@ -292,7 +293,7 @@ protected AbstractPropertyBindingResult createBeanPropertyBindingResult() {
 	public void initDirectFieldAccess() {
 		Assert.state(this.bindingResult == null,
 				"DataBinder is already initialized - call initDirectFieldAccess before other configuration methods");
-		this.bindingResult = createDirectFieldBindingResult();
+		this.directFieldAccess = true;
 	}
 
 	/**
@@ -427,13 +428,21 @@ public boolean isIgnoreInvalidFields() {
 	}
 
 	/**
-	 * Register fields that should be allowed for binding. Default is all
-	 * fields. Restrict this for example to avoid unwanted modifications
-	 * by malicious users when binding HTTP request parameters.
-	 * <p>Supports "xxx*", "*xxx" and "*xxx*" patterns. More sophisticated matching
-	 * can be implemented by overriding the {@code isAllowed} method.
-	 * <p>Alternatively, specify a list of <i>disallowed</i> fields.
-	 * @param allowedFields array of field names
+	 * Register field patterns that should be allowed for binding.
+	 * <p>Default is all fields.
+	 * <p>Restrict this for example to avoid unwanted modifications by malicious
+	 * users when binding HTTP request parameters.
+	 * <p>Supports {@code "xxx*"}, {@code "*xxx"}, {@code "*xxx*"}, and
+	 * {@code "xxx*yyy"} matches (with an arbitrary number of pattern parts), as
+	 * well as direct equality.
+	 * <p>The default implementation of this method stores allowed field patterns
+	 * in {@linkplain PropertyAccessorUtils#canonicalPropertyName(String) canonical}
+	 * form. Subclasses which override this method must therefore take this into
+	 * account.
+	 * <p>More sophisticated matching can be implemented by overriding the
+	 * {@link #isAllowed} method.
+	 * <p>Alternatively, specify a list of <i>disallowed</i> field patterns.
+	 * @param allowedFields array of allowed field patterns
 	 * @see #setDisallowedFields
 	 * @see #isAllowed(String)
 	 * @see org.springframework.web.bind.ServletRequestDataBinder
@@ -479,8 +488,7 @@ public void setDisallowedFields(String... disallowedFields) {
 		else {
 			String[] fieldPatterns = new String[disallowedFields.length];
 			for (int i = 0; i < fieldPatterns.length; i++) {
-				String field = PropertyAccessorUtils.canonicalPropertyName(disallowedFields[i]);
-				fieldPatterns[i] = field.toLowerCase(Locale.ROOT);
+				fieldPatterns[i] = PropertyAccessorUtils.canonicalPropertyName(disallowedFields[i]);
 			}
 			this.disallowedFields = fieldPatterns;
 		}
@@ -577,6 +585,7 @@ public void setValidator(Validator validator) {
 		this.validators.clear();
 		this.validators.add(validator);
 	}
+		}
 
 	private void assertValidators(Validator... validators) {
 		Assert.notNull(validators, "Validators required");
@@ -813,8 +822,13 @@ protected void checkAllowedFields(MutablePropertyValues mpvs) {
 	protected boolean isAllowed(String field) {
 		String[] allowed = getAllowedFields();
 		String[] disallowed = getDisallowedFields();
-		return ((ObjectUtils.isEmpty(allowed) || PatternMatchUtils.simpleMatch(allowed, field)) &&
-				(ObjectUtils.isEmpty(disallowed) || !PatternMatchUtils.simpleMatch(disallowed, field.toLowerCase(Locale.ROOT))));
+		if (!ObjectUtils.isEmpty(allowed) && !PatternMatchUtils.simpleMatch(allowed, field)) {
+			return false;
+		}
+		if (!ObjectUtils.isEmpty(disallowed)) {
+			return !PatternMatchUtils.simpleMatchIgnoreCase(disallowed, field);
+		}
+		return true;
 	}
 
 	/**