Add tests

Author: tanya732

README.md

@@ -45,7 +45,7 @@ This library is supported for Java LTS versions 8, 11, 17 and 21. For issues on
 
 > Note - Support for ECDSA with curve secp256k1 and SHA-256 (ES256K) has been dropped since it has been [disabled in Java 15](https://www.oracle.com/java/technologies/javase/15-relnote-issues.html#JDK-8237219)
 
-> Note - The RSASSA-PSS algorithms (PS256, PS384, PS512) rely on the JVM for RSASSA-PSS support, which is available natively from Java 11 onwards. On Java 8, a security provider that implements `RSASSA-PSS` (such as [BouncyCastle](https://www.bouncycastle.org/)) must be registered on the classpath; no additional provider is bundled by this library.
+> Note - The RSASSA-PSS algorithms (PS256, PS384, PS512) rely on the JVM for RSASSA-PSS support, which is available natively from Java 11 onwards via the `SunRsaSign` provider ([JDK-8146293](https://bugs.openjdk.org/browse/JDK-8146293)). On Java 8, a security provider that implements `RSASSA-PSS` (such as [BouncyCastle](https://www.bouncycastle.org/)) must be registered on the classpath; no additional provider is bundled by this library.
 
 > :warning:  **Important security note:** JVM has a critical vulnerability for ECDSA Algorithms - [CVE-2022-21449](https://nvd.nist.gov/vuln/detail/CVE-2022-21449). Please review the details of the vulnerability and update your environment.
 ### Installation

lib/src/main/java/com/auth0/jwt/algorithms/Algorithm.java

@@ -250,6 +250,8 @@ public static Algorithm RSA512PSS(RSAKey key) throws IllegalArgumentException {
     }
 
     private static PSSParameterSpec pssParams(String hashAlgorithm, MGF1ParameterSpec mgf1Spec, int saltLength) {
+        // JWA (RFC 7518 §3.5) mandates MGF1 with the same hash as the digest and a salt length equal to
+        // the hash output size (32/48/64 bytes for SHA-256/384/512). Trailer field is the fixed value 1.
         return new PSSParameterSpec(hashAlgorithm, "MGF1", mgf1Spec, saltLength, 1);
     }
 

lib/src/main/java/com/auth0/jwt/algorithms/CryptoHelper.java

@@ -312,6 +312,9 @@ private static void setParameterIfPresent(Signature s, AlgorithmParameterSpec pa
             try {
                 s.setParameter(params);
             } catch (InvalidAlgorithmParameterException e) {
+                // Remapped to NoSuchAlgorithmException to keep the throws clause unchanged. The params
+                // are library-controlled (see Algorithm#pssParams), so this branch is effectively
+                // unreachable; it only fires if a provider rejects the fixed PSS spec entirely.
                 throw new NoSuchAlgorithmException(
                         "The algorithm parameters are invalid for the signature algorithm.", e);
             }

lib/src/test/java/com/auth0/jwt/algorithms/RSAPSSAlgorithmTest.java

@@ -4,6 +4,7 @@
 import com.auth0.jwt.exceptions.SignatureVerificationException;
 import org.bouncycastle.jce.provider.BouncyCastleProvider;
 import org.junit.AfterClass;
+import org.junit.Assume;
 import org.junit.BeforeClass;
 import org.junit.Rule;
 import org.junit.Test;
@@ -128,4 +129,53 @@ public void shouldFailPS256VerificationWithInvalidPublicKey() throws Exception {
         Algorithm verifier = Algorithm.RSA256PSS((RSAKey) readPublicKeyFromFile(INVALID_PUBLIC_KEY_FILE, "RSA"));
         verifier.verify(JWT.decode(jwt));
     }
+
+    @Test
+    public void shouldRejectPS256TokenWhenVerifiedWithPS384() throws Exception {
+        exception.expect(SignatureVerificationException.class);
+        exception.expectMessage("The Token's Signature resulted invalid when verified using the Algorithm: RSASSA-PSS");
+
+        Algorithm signer = Algorithm.RSA256PSS((RSAKey) readPrivateKeyFromFile(PRIVATE_KEY_FILE, "RSA"));
+        String jwt = asJWT(signer, PS256Header, auth0IssPayload);
+
+        Algorithm verifier = Algorithm.RSA384PSS((RSAKey) readPublicKeyFromFile(PUBLIC_KEY_FILE, "RSA"));
+        verifier.verify(JWT.decode(jwt));
+    }
+
+    @Test
+    public void shouldRejectPS256TokenWhenVerifiedWithPS512() throws Exception {
+        exception.expect(SignatureVerificationException.class);
+        exception.expectMessage("The Token's Signature resulted invalid when verified using the Algorithm: RSASSA-PSS");
+
+        Algorithm signer = Algorithm.RSA256PSS((RSAKey) readPrivateKeyFromFile(PRIVATE_KEY_FILE, "RSA"));
+        String jwt = asJWT(signer, PS256Header, auth0IssPayload);
+
+        Algorithm verifier = Algorithm.RSA512PSS((RSAKey) readPublicKeyFromFile(PUBLIC_KEY_FILE, "RSA"));
+        verifier.verify(JWT.decode(jwt));
+    }
+
+    /**
+     * Exercises the JDK-native RSASSA-PSS implementation (SunRsaSign, Java 11+) rather than the
+     * BouncyCastle provider the rest of this class relies on. Skipped on Java 8, whose built-in
+     * providers do not implement RSASSA-PSS.
+     */
+    @Test
+    public void shouldSignAndVerifyPS256WithJdkNativeProvider() throws Exception {
+        Assume.assumeFalse("Requires JDK-native RSASSA-PSS (Java 11+)",
+                System.getProperty("java.specification.version").equals("1.8"));
+
+        Security.removeProvider(bcProvider.getName());
+        try {
+            Algorithm algorithm = Algorithm.RSA256PSS(
+                    (RSAPublicKey) readPublicKeyFromFile(PUBLIC_KEY_FILE, "RSA"),
+                    (RSAPrivateKey) readPrivateKeyFromFile(PRIVATE_KEY_FILE, "RSA"));
+
+            String jwt = asJWT(algorithm, PS256Header, auth0IssPayload);
+
+            assertSignaturePresent(jwt);
+            algorithm.verify(JWT.decode(jwt));
+        } finally {
+            Security.insertProviderAt(bcProvider, 1);
+        }
+    }
 }