RFR: 8263404: RsaPrivateKeySpec is always recognized as RSAPrivateCrtKeySpec in RSAKeyFactory.engineGetKeySpec [v4]

[SalusaSecondus]

On Sat, 20 Mar 2021 17:52:00 GMT, SalusaSecondus <github.com+829871+SalusaSecondus at openjdk.org> wrote:

>> @valeriepeng Sorry for the delay. There were unknown Windows build failure during the pre-submit tests that I have to rebase my commits on top of the  master tip. This new revision should cover all comments you left before. Thank you!
>
> Mike,
> 
> From what I can find, if you try to get a spec from a non-extractable key you'll get an `InvalidKeySpecException`.
> 1. `C_GetAttributeValue`will throw a `PKCS11Exception`
> 2. The `PKCS11Exception` gets caught in [P11KeyFactory](https://github.com/openjdk/jdk/blob/master/src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11KeyFactory.java#L98-L99) which rethrows it as an `InvalidKeySpecException`.

We seem to have a choice and I'm not sure the best way to approach this.

1. We trust the properties in `P11Key` and just ask it if the values are both sensitive and extractable. [1]
2. But if we already trust P11Key, why not also trust that it properly implements the RSAPrivateKey interfaces [2]. This is the strategy used by the snippet I posted earlier (delegating to `implGetSoftwareFactory()`)
3. We don't trust P11Key except to use getKeyId(), this yields the current design where we pull the attributes every time the factory needs them.

We should probably reduce calls to `C_GetAttributeValue` as they may be very slow. At the least they cross the JNI boundary and at worst they interact with a slow piece of hardware (possibly over a network). The current design will have two calls in a worst case, but is likely to have only one call the vast majority of the time.

[1] https://github.com/openjdk/jdk/blob/master/src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11Key.java#L92
[2] https://github.com/openjdk/jdk/blob/master/src/jdk.crypto.cryptoki/share/classes/sun/security/pkcs11/P11Key.java#L375-L406

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PR: https://git.openjdk.java.net/jdk/pull/2949