FIPS HmacSHA512 with small key

[tomjshore]

Hello I'm not sure if this a bug or not. But it feels like something the should be investigated.

The second test in the following test case fails. This is because when doing Mac.getInstance(HMAC_SHA_512) it makes an Mac object with no spi. So when doing mac.init(SMALL_KEY) It will check if there is a spi if there is not it will iterate over all the providers of Mac which does not throw an exception when doing engineInit

So ideally to fix this when doing Mac.getInstance(HMAC_SHA_512) it would populate the spi.

import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
import java.security.Security;

import static org.junit.jupiter.api.Assertions.assertThrows;

class MacTest
{
    private static final String HMAC_SHA_512 = "HmacSHA512";
    private static final Key SMALL_KEY = new SecretKeySpec("0".getBytes(), HMAC_SHA_512);

    @BeforeAll
    static void setup() {
        System.setProperty("org.bouncycastle.fips.approved_only", "true");
        Security.insertProviderAt(new BouncyCastleFipsProvider(), 1);
    }

    @Test
    void testMacWithBCFIPSProvider() throws Exception {
        Mac mac = Mac.getInstance(HMAC_SHA_512, "BCFIPS");
        assertThrows(Exception.class, () -> mac.init(SMALL_KEY));
    }

    @Test
    void testMacWithDefaultProvider() throws Exception {
        Mac mac = Mac.getInstance(HMAC_SHA_512);
        assertThrows(Exception.class, () -> mac.init(SMALL_KEY));
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.fips.fipsmac</groupId>
  <artifactId>FipsMac</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <maven.compiler.source>21</maven.compiler.source>
    <maven.compiler.target>21</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.bouncycastle</groupId>
      <artifactId>bctls-fips</artifactId>
      <version>2.1.23</version>
    </dependency>

    <dependency>
      <groupId>org.junit.jupiter</groupId>
      <artifactId>junit-jupiter</artifactId>
      <version>5.11.4</version>
      <scope>test</scope>
    </dependency>

  </dependencies>

</project>