On Tue, 22 Nov 2022 17:42:06 GMT, Weijun Wang <wei...@openjdk.org> wrote:

>> Inside JDK we support a lot of X.509 certificate extensions. Almost every 
>> extension has a rule about what is legal or not. For example, the names in 
>> `SubjectAlternativeNameExtension` cannot be missing or empty. Usually, a 
>> rule is enforced in the `encode()` method, where the extension value is 
>> assigned null for illegal extension and the method throws an `IOException`. 
>> However, before the `encode()` method is called, the illegal extension can 
>> always be created successfully, whether from a constructor using extension 
>> components (For example, `new SubjectAlternativeNameExtension(names)`) or 
>> using the encoded value (for example, `new 
>> SubjectAlternativeNameExtension(derEncoding)`).
>> 
>> This code change tries to prevent illegal extensions from being created 
>> right from the beginning but the solution is not complete. Precisely, for 
>> constructors using extension components, new checks are added to ensure the 
>> correct components are provided and the extension can be encoded correctly. 
>> Fortunately, most of these conditions are already met inside JDK calls to 
>> them. The only exception is inside the `keytool -gencrl` command where the 
>> reason code of a revoked certificate could be zero. This has been fixed in 
>> this code change. There are some constructors having no arguments at all. 
>> These are useless and also removed.
>> 
>> On the other hand, constructors using the encoded value are complicated. 
>> Some of them check for legal values, some do not. However, since the 
>> encoding is read from the argument and already stored inside the object, 
>> there is no need to calculate the encoding in the `encode()` method and this 
>> method always succeed.
>> 
>> In short, while we cannot ensure the extensions created are perfectly legal, 
>> we ensure their `encode()` methods are always able to find a non-null 
>> extension value to write out.
>> 
>> More fine comments in the code change.
>
> Weijun Wang has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   IssuerAlternativeNameExtension names

More comments.

src/java.base/share/classes/sun/security/x509/CertificatePoliciesExtension.java 
line 113:

> 111:     public CertificatePoliciesExtension(Boolean critical,
> 112:             List<PolicyInformation> certPolicies) throws IOException {
> 113:         if (certPolicies == null || certPolicies.isEmpty()) {

You should probably also change `PolicyInformation(CertificatePolicyId 
policyIdentifier,            Set<PolicyQualifierInfo> policyQualifiers)` to 
check for a null policyIdentifier and an empty policyQualifiers set.

src/java.base/share/classes/sun/security/x509/Extension.java line 178:

> 176: 
> 177:         Objects.requireNonNull(extensionId,
> 178:                 "Null OID to encode for the extension!");

I would probably drop the exclamation points. And change "Null OID" to "No OID".

src/java.base/share/classes/sun/security/x509/NameConstraintsExtension.java 
line 142:

> 140:         if (permitted == null && excluded == null) {
> 141:             throw new IllegalArgumentException(
> 142:                     "permitted and exclude cannot both be null");

s/exclude/excluded/

src/java.base/share/classes/sun/security/x509/PolicyMappingsExtension.java line 
78:

> 76:      * Create a PolicyMappings with the List of CertificatePolicyMap.
> 77:      *
> 78:      * @param maps the List of CertificatePolicyMap, cannot be null or 
> empty.

Do you want to add similar null checks to the `CertificatePolicyMap` ctor?

src/java.base/share/classes/sun/security/x509/SubjectAlternativeNameExtension.java
 line 91:

> 89:      */
> 90:     public SubjectAlternativeNameExtension(Boolean critical, GeneralNames 
> names)
> 91:             throws IOException {

`GeneralNames` should probably also be modified so that it cannot contain an 
empty or null List.

src/java.base/share/classes/sun/security/x509/SubjectInfoAccessExtension.java 
line 89:

> 87:         if (accessDescriptions == null || accessDescriptions.isEmpty()) {
> 88:             throw new IllegalArgumentException(
> 89:                     "AccessDescription cannot be null or empty");

s/AccessDescription/accessDescriptions/

src/java.base/share/classes/sun/security/x509/SubjectKeyIdentifierExtension.java
 line 76:

> 74:      */
> 75:     public SubjectKeyIdentifierExtension(byte[] octetString)
> 76:             throws IOException {

Do you want to change the `KeyIdentifer` ctor to check for null instead of 
letting it throw NPE?

-------------

PR: https://git.openjdk.org/jdk/pull/11137

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