RFR: 8336499: Failure when creating non-CRT RSA private keys in SunPKCS11 [v2]

[Martin Balao]

> Hi,
> 
> I'd like to make a proposal to fix [JDK-8336499](https://bugs.openjdk.org/browse/JDK-8336499).
> 
> With the proposed change, a non-sensitive RSA private key is first interpreted as a CRT key. If that fails (e.g. one of the attributes is not available), a second attempt is made to interpret the key as a non-CRT key. In this second attempt, only the required attributes (`CKA_MODULUS` and `CKA_PRIVATE_EXPONENT`) are queried. If this still fails, the key is handled as an opaque key. Most non-sensitive key cases will require a single query, retaining the performance improvement made in [8271566](https://bugs.openjdk.org/browse/JDK-8271566). No changes were made to sensitive keys: they are still handled as opaque keys.
> 
> No regressions observed in `jdk/sun/security/pkcs11`.
> 
> As explained in a [JBS comment](https://bugs.openjdk.org/browse/JDK-8336499?focusedId=14690278&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14690278), a regression test for this fix is not easy because the NSS Software Token cannot create non-CRT RSA private keys without a `CKA_PUBLIC_EXPONENT` (as required by the PKCS 11 standard v2.40 and above). A call to `P11RSAKeyFactory::generatePrivate` would fail and the key is never wrapped in a `P11Key` object. A PKCS 11 library implementing a standard previous to 2.40 would be required. With that said, I manually exercised the `asNonCRT` path in the proposed change by using a CRT key and forcing `asCRT` to fail with the debugger.
> 
> Thanks,
> Martin.-

Martin Balao has updated the pull request incrementally with one additional commit since the last revision:

  Refactoring and simplification. Session for operations is not needed.
  
  Co-authored-by: Martin Balao <mbalao at redhat.com>
  Co-authored-by: Francisco Ferrari Bihurriet <fferrari at redhat.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/20204/files
  - new: https://git.openjdk.org/jdk/pull/20204/files/dc005819..27e66d7e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20204&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20204&range=00-01

  Stats: 66 lines in 1 file changed: 18 ins; 26 del; 22 mod
  Patch: https://git.openjdk.org/jdk/pull/20204.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20204/head:pull/20204

PR: https://git.openjdk.org/jdk/pull/20204