This bug was initially created as a copy of Bug #2007331

I am copying this bug because: 

We need to fix this for RHEL 8 - OpenJDK 11 too.

Mac keys generated by KeyGenerator do not work with the corresponding Mac in FIPS mode. The same failure is obtained with keys imported from plain bytes (through the Bug 1991003 work). This second case had already been identified and fixed in Bug 2020290 (and reported upstream [5]).

The Mac service initialization fails with CKR_KEY_TYPE_INCONSISTENT because the generated key doesn't have the CKA_SIGN attribute: see how NSC_SignInit() calls sftk_InitGeneric(..., CKA_SIGN) to verify the attribute [1], this ends up calling sftk_isTrue(key, operation) with operation=CKA_SIGN [2].


Reproducer, for the 'generate' operation:
/////////////////////////////////////////
import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import java.security.Key;

public class MacTest {
    public static void main(String[] args) throws Exception {
        Mac mac = Mac.getInstance("HmacSHA256");
        KeyGenerator kg = KeyGenerator.getInstance("HmacSHA256");
        Key key = kg.generateKey();
        System.out.println("key: " + key);
        mac.init(key);
    }
}


Reproducer, for the 'import' operation (adapted from bug 2007331, comment 2):
/////////////////////////////////////////////////////////////////////////////
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.Mac;
import java.security.Key;

public class MacTest {
    public static void main(String[] args) throws Exception {
        Mac mac = Mac.getInstance("HmacSHA256");
        final byte keyBytes[] = "ThisIsAPlainKey!".getBytes();
        Key key = new SecretKeySpec(keyBytes, "HmacSHA256");
        System.out.println("key: " + key);
        mac.init(key);
    }
}


Failure (the same for both reproducers):
////////////////////////////////////////
Exception in thread "main" java.security.InvalidKeyException: init() failed
	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Mac.engineInit(P11Mac.java:214)
	at java.base/javax.crypto.Mac.chooseProvider(Mac.java:365)
	at java.base/javax.crypto.Mac.init(Mac.java:434)
	at MacTest.main(MacTest.java:11)
Caused by: sun.security.pkcs11.wrapper.PKCS11Exception: CKR_KEY_TYPE_INCONSISTENT
	at jdk.crypto.cryptoki/sun.security.pkcs11.wrapper.PKCS11.C_SignInit(Native Method)
	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Mac.initialize(P11Mac.java:183)
	at jdk.crypto.cryptoki/sun.security.pkcs11.P11Mac.engineInit(P11Mac.java:212)
	... 3 more


Additional info:
////////////////
Mac however works with key obtained from "SunTls12KeyMaterial" (internal class) following way: [3]. Note that SunPKCS11 provider in earlier JDKs did not provide Mac key generators and this was the only way (I am aware of) to obtain Mac key. Mac key generators were added to SunPKCS11 together with SHA3 support [4].

This means that the 'generate' operation isn't available in earlier JDKs, however the issue for the 'import' operation is reproducible in 8 & 11.

[1] https://github.com/nss-dev/nss/blob/NSS_3_67_RTM/lib/softoken/pkcs11c.c#L2777-L2778
[2] https://github.com/nss-dev/nss/blob/NSS_3_67_RTM/lib/softoken/pkcs11c.c#L444
[3] https://github.com/judovana/CryptoTest/blob/a4bb593d6faa2052606fffb0554141c63468efbb/cryptotest/utils/KeysNaiveGenerator.java#L144
[4] https://bugs.openjdk.java.net/browse/JDK-8242332
[5] https://bugs.openjdk.java.net/browse/JDK-8278640