prbprbprb
commented
2 years ago I guess it's a bug... The authType parameter to checkServerTrusted() isn't well defined for TLS 1.3 due to the authentication changes.
BoringSSL and thus Conscrypt went with GENERIC but OpenJDK went with UNKNOWN (which to my mind is even less descriptive) (tested on OpenJDK 11 & 16). Unfortunately it matters when using a SunJSSE TrustManager as it uses this parameter to determine which key usage bits need to be set on the server certificate based on hard coded lists.
Changing Conscrypt is an option but with limitations... Once Android shipped with TLS1.3 as default, we got a number of bugs from apps with custom trust managers which didn't handle GENERIC as an authType, so if we change it to UNKNOWN we'll break those apps all over again.
On the plus side, this call is abstracted through platform-specific code, so we could rewrite GENERIC to UNKNOWN for OpenJDK only with hopefully less breakage or make it configurable.
In the meantime, you could achieve the same thing yourself with a delegating trust manager, e.g.
TrustManagerFactory tmf = TrustManagerFactory.getInstance(tmftype, trustProvider);
tmf.init(ks);
TrustManager[] tm = tmf.getTrustManagers();
TrustManager[] delegateTm = new TrustManager[] {
// You should deal with the case where there's more than 1 ;)
new DelegatingTrustManager((X509ExtendedTrustManager) tm[0])
};
[...]
private static class DelegatingTrustManager extends X509ExtendedTrustManager {
private final X509ExtendedTrustManager delegate;
public DelegatingTrustManager(X509ExtendedTrustManager delegate) {
this.delegate = delegate;
}
public void checkServerTrusted(X509Certificate[] chain, String authType, Socket socket) throws CertificateException {
if ("GENERIC".equals(authType)) {
authType = "UNKNOWN";
}
delegate.checkServerTrusted(chain, authType, socket);
}
// etc - don't forget to delegate all methods
}
davidben
hessjcg
mperktold
The following tests fails:
To be exact, only the testMixed fails, with the exception:
The problem is a
SSLContextfrom the Conscrypt provider is used, with aTrustManagerfrom SunJSSE, the default provider used.But when I explicitly ensure than the
TrustManageris comming fromSSLContext, everything is OK.The problem only arise withe the
SSLContextis using theTLSv1.3. WithTLSv1.2, everything is fine.I tested that with Java 16 and Conscrypt 2.5.2.
Is that a bug or a feature ?