* Note that this method is only apply to DHPublicKey at present. * * @param key the key object, cannot be null * * @throws NullPointerException if {@code key} is null * @throws InvalidKeyException if {@code key} is invalid */ public static final void validate(Key key) throws InvalidKeyException { if (key == null) { throw new NullPointerException( "The key to be validated cannot be null"); } if (key instanceof DHPublicKey) { validateDHPublicKey((DHPublicKey)key); } } /** * Returns whether the key spec is valid or not. *
* Note that this method is only apply to DHPublicKeySpec at present. * * @param keySpec * the key spec object, cannot be null * * @throws NullPointerException if {@code keySpec} is null * @throws InvalidKeyException if {@code keySpec} is invalid */ public static final void validate(KeySpec keySpec) throws InvalidKeyException { if (keySpec == null) { throw new NullPointerException( "The key spec to be validated cannot be null"); } if (keySpec instanceof DHPublicKeySpec) { validateDHPublicKey((DHPublicKeySpec)keySpec); } } /** * Returns whether the specified provider is Oracle provider or not. * * @param providerName * the provider name * @return true if, and only if, the provider of the specified * {@code providerName} is Oracle provider */ public static final boolean isOracleJCEProvider(String providerName) { return providerName != null && (providerName.equals("SunJCE") || providerName.equals("SunMSCAPI") || providerName.startsWith("SunPKCS11")); } /** * Check the format of TLS PreMasterSecret. *
* To avoid vulnerabilities described by section 7.4.7.1, RFC 5246, * treating incorrectly formatted message blocks and/or mismatched * version numbers in a manner indistinguishable from correctly * formatted RSA blocks. * * RFC 5246 describes the approach as: *
{@literal
*
* 1. Generate a string R of 48 random bytes
*
* 2. Decrypt the message to recover the plaintext M
*
* 3. If the PKCS#1 padding is not correct, or the length of message
* M is not exactly 48 bytes:
* pre_master_secret = R
* else If ClientHello.client_version <= TLS 1.0, and version
* number check is explicitly disabled:
* premaster secret = M
* else If M[0..1] != ClientHello.client_version:
* premaster secret = R
* else:
* premaster secret = M
*
* Note that #2 should have completed before the call to this method.
* }
*
* @param clientVersion the version of the TLS protocol by which the
* client wishes to communicate during this session
* @param serverVersion the negotiated version of the TLS protocol which
* contains the lower of that suggested by the client in the client
* hello and the highest supported by the server.
* @param encoded the encoded key in its "RAW" encoding format
* @param isFailOver whether or not the previous decryption of the
* encrypted PreMasterSecret message run into problem
* @return the polished PreMasterSecret key in its "RAW" encoding format
*/
public static byte[] checkTlsPreMasterSecretKey(
int clientVersion, int serverVersion, SecureRandom random,
byte[] encoded, boolean isFailOver) {
if (random == null) {
random = JCAUtil.getSecureRandom();
}
byte[] replacer = new byte[48];
random.nextBytes(replacer);
if (!isFailOver && (encoded != null)) {
// check the length
if (encoded.length != 48) {
// private, don't need to clone the byte array.
return replacer;
}
int encodedVersion =
((encoded[0] & 0xFF) << 8) | (encoded[1] & 0xFF);
if (clientVersion != encodedVersion) {
if (clientVersion > 0x0301 || // 0x0301: TLSv1
serverVersion != encodedVersion) {
encoded = replacer;
} // Otherwise, For compatibility, we maintain the behavior
// that the version in pre_master_secret can be the
// negotiated version for TLS v1.0 and SSL v3.0.
}
// private, don't need to clone the byte array.
return encoded;
}
// private, don't need to clone the byte array.
return replacer;
}
/**
* Returns whether the Diffie-Hellman public key is valid or not.
*
* Per RFC 2631 and NIST SP800-56A, the following algorithm is used to
* validate Diffie-Hellman public keys:
* 1. Verify that y lies within the interval [2,p-1]. If it does not,
* the key is invalid.
* 2. Compute y^q mod p. If the result == 1, the key is valid.
* Otherwise the key is invalid.
*/
private static void validateDHPublicKey(DHPublicKey publicKey)
throws InvalidKeyException {
DHParameterSpec paramSpec = publicKey.getParams();
BigInteger p = paramSpec.getP();
BigInteger g = paramSpec.getG();
BigInteger y = publicKey.getY();
validateDHPublicKey(p, g, y);
}
private static void validateDHPublicKey(DHPublicKeySpec publicKeySpec)
throws InvalidKeyException {
validateDHPublicKey(publicKeySpec.getP(),
publicKeySpec.getG(), publicKeySpec.getY());
}
private static void validateDHPublicKey(BigInteger p,
BigInteger g, BigInteger y) throws InvalidKeyException {
// For better interoperability, the interval is limited to [2, p-2].
BigInteger leftOpen = BigInteger.ONE;
BigInteger rightOpen = p.subtract(BigInteger.ONE);
if (y.compareTo(leftOpen) <= 0) {
throw new InvalidKeyException(
"Diffie-Hellman public key is too small");
}
if (y.compareTo(rightOpen) >= 0) {
throw new InvalidKeyException(
"Diffie-Hellman public key is too large");
}
// y^q mod p == 1?
// Unable to perform this check as q is unknown in this circumstance.
// p is expected to be prime. However, it is too expensive to check
// that p is prime. Instead, in order to mitigate the impact of
// non-prime values, we check that y is not a factor of p.
BigInteger r = p.remainder(y);
if (r.equals(BigInteger.ZERO)) {
throw new InvalidKeyException("Invalid Diffie-Hellman parameters");
}
}
/**
* Trim leading (most significant) zeroes from the result.
*
* @throws NullPointerException if {@code b} is null
*/
public static byte[] trimZeroes(byte[] b) {
int i = 0;
while ((i < b.length - 1) && (b[i] == 0)) {
i++;
}
if (i == 0) {
return b;
}
byte[] t = new byte[b.length - i];
System.arraycopy(b, i, t, 0, t.length);
return t;
}
}