oddbjornkvalsund / wcsa

Windows Certificate Store Aggregator

Windows Certificate Store Aggregator

Tooling to read certificate stores in Windows for Java versions < 19 (2022)

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The JDK-6782021 issue that was reported in 2008 was finally fixed with Java 19, so this is no longer an issue for modern Java versions 🥳

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Problem

The SunMSCAPI JCA provider¹ used by both Oracle JDK/JRE and OpenJDK only provides access to certificates and private keys stored in the Current User certificate store. The reason for this is that it uses the CertOpenSystemStore WinCrypt API call that explicitly states²:

Only current user certificates are accessible using this method, not the local machine store.

So if you need access to certificates and/or private keys stored in the Windows Local Computer certificate store from a Java program, you are out of luck.

Solution

This software uses the Microsoft Detours³ library to intercept CertOpenSystemStore function calls and instead returns a handle to a collection type certificate store that aggregates both the Current User and Local Computer certificate stores. In addition, it intercepts calls to CryptAcquireContext and adds CRYPT_MACHINE_KEYSET to dwFlags if the original call fails with an NTE_BAD_KEYSET ("Keyset does not exist") error. This is required to use keys that are stored in the Local Computer certificate store.

Get

Download prebuild binaries in the release section of this repo or clone this repo and build with nmake (requires a working Win32 build environment).

Usage

Instead of starting your application with java -jar myapp.jar, you bootstrap it with the Windows Detours³ withdll utility: withdll.exe /d:wcsa.dll java -jar myapp.jar

Note that you might need to explicitly grant certificate key read permissions to the Windows user that runs the process.

Limitations

• The returned collection certificate store is read-only, so adding, updating or removing certificates/private keys will fail.
• This software intercepts all calls to CertOpenSystemStore, so make sure this is what you really want before proceeding to use this in production.

Licence

MIT Open Source Licence.

References

1. SunMSCAPI
2. WinCrypt remarks
3. Microsoft Detours
4. JDK-6782021