Potential NPE from `MethodParameter.getMethod()` check in `KotlinDelegate.hasDefaultValue()`

[openrefactorymunawar]

Summary

In your repository (MAVENorg.springframework:spring-web @ 6.1.12), we have found a bug that may require your attention.

In file: AbstractNamedValueArgumentResolver.java, class: KotlinDelegate, method: hasDefaultValue, there is a potential Null pointer dereference at:

spring-framework/spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractNamedValueArgumentResolver.java

Line 341 in 3476425

Method method = Objects.requireNonNull(parameter.getMethod());

In other places of the code (e.g.,

spring-framework/spring-core/src/main/java/org/springframework/core/MethodParameter.java

Line 513 in d79258a

Method method = getMethod();

or

spring-framework/spring-core/src/main/java/org/springframework/core/MethodParameter.java

Line 774 in d79258a

Method method = getMethod();

), the return value of the getMethod method was checked for null value. But if we put it directly inside Objects.requireNonNull, we may have an exception.

A potential fix will be to replace the following line

Method method = Objects.requireNonNull(parameter.getMethod());

with

Method method = parameter.getMethod();
if (method == null) {
    return false;
}

Another option could be to use Objects.requireNonNullElse.

Sponsorship and Support

This work is done by the security researchers from OpenRefactory and is supported by the Open Source Security Foundation (OpenSSF): Project Alpha-Omega. Alpha-Omega is a project partnering with open source software project maintainers to systematically find new, as-yet-undiscovered vulnerabilities in open source code - and get them fixed – to improve global software supply chain security.

The bug is found by running the Intelligent Code Repair (iCR) tool by OpenRefactory and then manually triaging the results.

[jhoeller]

Good catch, this is worth turning into a more defensive check within that local delegate (also in the equivalent code in AbstractNamedValueMethodArgumentResolver for Spring MVC). That said, in practice it is not an actual bug since all current invocation scenarios are method-based anyway.