RFR: 8346094: Harden X509CertImpl.getExtensionValue for NPE cases

[Konanki Sreenath]

On Wed, 5 Feb 2025 03:55:18 GMT, Nibedita Jena <duke at openjdk.org> wrote:

>> Earlier code will trigger NPE if the certificate does not contain the extensions or if the requested extensions does not exist. The better approach for hardening **getExtensionValue** here is to to check for NULL explicitly before calling **getExtensionValue()** and avoding try-catch block which ensures the readability and maintainability.
>> 
>> After scanning in multiple places where invokng getExtensions on the X509CertInfo reference, the check for NULL is added in the **getKeyUsage()** as well while calling before **getExtensionValue()**
>> 
>> The associated tests are written and added in test class **CertificateExtensions**. Which will ensure to validate the 
>> **getExtensionValue()** and **getKeyUsage()** methods in **X509CertImpl** class.
>
> test/jdk/java/security/cert/X509Certificate/CertificateExtensions.java line 136:
> 
>> 134:     public static sun.security.x509.CertificateExtensions createCertificateExtensions(PublicKey publicKey) throws IOException, NoSuchAlgorithmException {
>> 135:         // Create Extensions
>> 136:         sun.security.x509.CertificateExtensions certificateExtensions = new sun.security.x509.CertificateExtensions();
> 
> Same comment

addressed indentation

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PR Review Comment: https://git.openjdk.org/jdk/pull/23315#discussion_r1944142275