RFR: 8331008: KDF Implementation

[Kevin Driver]

On Wed, 8 May 2024 20:46:57 GMT, Jamil Nimeh <jnimeh at openjdk.org> wrote:

>> Introduce an API for Key Derivation Functions (KDFs), which are cryptographic algorithms for deriving additional keys from a secret key and other data. See [JEP 478](https://openjdk.org/jeps/478).
>
> src/java.base/share/classes/com/sun/crypto/provider/HkdfKeyDerivation.java line 370:
> 
>> 368:         }
>> 369:         int rounds = (outLen + hmacLen - 1) / hmacLen;
>> 370:         kdfOutput = new byte[rounds * hmacLen];
> 
> Are we missing a check to ensure that the `outLen` parameter is less than or equal to 255 * HashLen?  See RFC 5869 sec. 2.3.

Yes! I intended to. Thanks for catching it.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18924#discussion_r1594639470