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

[Michael StJohns]

On 3/20/2021 2:46 PM, SalusaSecondus wrote:
> 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
>
> -------------
>
> PR: https://git.openjdk.java.net/jdk/pull/2949

Actually, the important lines are 63-66 and 365-373:

  * If the components are not accessible, we use a generic class that
  * only implements PrivateKey (or SecretKey). Whether the components of a
  * key are extractable is automatically determined when the key object is
  * created.

> attributes = getAttributes(session, keyID, attributes, new 
> CK_ATTRIBUTE[] {
>             new CK_ATTRIBUTE(CKA_TOKEN),
>             new CK_ATTRIBUTE(CKA_SENSITIVE),
>             new CK_ATTRIBUTE(CKA_EXTRACTABLE),
>         });
>         if (attributes[1].getBoolean() || (attributes[2].getBoolean() 
> == false)) {
>             return new P11PrivateKey
>                 (session, keyID, algorithm, keyLength, attributes);
>         }

If the key is non-extractable, then the only attributes will be these 
three and the underlying type will be P11Key.P11PrivateKey rather than 
one of the RSA variants.

Simple check at the top.

Mike