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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package sun.security.rsa;
import java.math.BigInteger;
import java.security.*;
import java.security.interfaces.*;
import java.security.spec.*;
import sun.security.action.GetPropertyAction;
/**
* KeyFactory for RSA keys. Keys must be instances of PublicKey or PrivateKey
* and getAlgorithm() must return "RSA". For such keys, it supports conversion
* between the following:
*
* For public keys:
* . PublicKey with an X.509 encoding
* . RSAPublicKey
* . RSAPublicKeySpec
* . X509EncodedKeySpec
*
* For private keys:
* . PrivateKey with a PKCS#8 encoding
* . RSAPrivateKey
* . RSAPrivateCrtKey
* . RSAPrivateKeySpec
* . RSAPrivateCrtKeySpec
* . PKCS8EncodedKeySpec
* (of course, CRT variants only for CRT keys)
*
* Note: as always, RSA keys should be at least 512 bits long
*
* @since 1.5
* @author Andreas Sterbenz
*/
public final class RSAKeyFactory extends KeyFactorySpi {
private final static Class<?> rsaPublicKeySpecClass =
RSAPublicKeySpec.class;
private final static Class<?> rsaPrivateKeySpecClass =
RSAPrivateKeySpec.class;
private final static Class<?> rsaPrivateCrtKeySpecClass =
RSAPrivateCrtKeySpec.class;
private final static Class<?> x509KeySpecClass = X509EncodedKeySpec.class;
private final static Class<?> pkcs8KeySpecClass = PKCS8EncodedKeySpec.class;
public final static int MIN_MODLEN = 512;
public final static int MAX_MODLEN = 16384;
/*
* If the modulus length is above this value, restrict the size of
* the exponent to something that can be reasonably computed. We
* could simply hardcode the exp len to something like 64 bits, but
* this approach allows flexibility in case impls would like to use
* larger module and exponent values.
*/
public final static int MAX_MODLEN_RESTRICT_EXP = 3072;
public final static int MAX_RESTRICTED_EXPLEN = 64;
private static final boolean restrictExpLen =
"true".equalsIgnoreCase(AccessController.doPrivileged(
new GetPropertyAction(
"sun.security.rsa.restrictRSAExponent", "true")));
// instance used for static translateKey();
private final static RSAKeyFactory INSTANCE = new RSAKeyFactory();
public RSAKeyFactory() {
// empty
}
/**
* Static method to convert Key into an instance of RSAPublicKeyImpl
* or RSAPrivate(Crt)KeyImpl. If the key is not an RSA key or cannot be
* used, throw an InvalidKeyException.
*
* Used by RSASignature and RSACipher.
*/
public static RSAKey toRSAKey(Key key) throws InvalidKeyException {
if ((key instanceof RSAPrivateKeyImpl) ||
(key instanceof RSAPrivateCrtKeyImpl) ||
(key instanceof RSAPublicKeyImpl)) {
return (RSAKey)key;
} else {
return (RSAKey)INSTANCE.engineTranslateKey(key);
}
}
/*
* Single test entry point for all of the mechanisms in the SunRsaSign
* provider (RSA*KeyImpls). All of the tests are the same.
*
* For compatibility, we round up to the nearest byte here:
* some Key impls might pass in a value within a byte of the
* real value.
*/
static void checkRSAProviderKeyLengths(int modulusLen, BigInteger exponent)
throws InvalidKeyException {
checkKeyLengths(((modulusLen + 7) & ~7), exponent,
RSAKeyFactory.MIN_MODLEN, Integer.MAX_VALUE);
}
/**
* Check the length of an RSA key modulus/exponent to make sure it
* is not too short or long. Some impls have their own min and
* max key sizes that may or may not match with a system defined value.
*
* @param modulusLen the bit length of the RSA modulus.
* @param exponent the RSA exponent
* @param minModulusLen if > 0, check to see if modulusLen is at
* least this long, otherwise unused.
* @param maxModulusLen caller will allow this max number of bits.
* Allow the smaller of the system-defined maximum and this param.
*
* @throws InvalidKeyException if any of the values are unacceptable.
*/
public static void checkKeyLengths(int modulusLen, BigInteger exponent,
int minModulusLen, int maxModulusLen) throws InvalidKeyException {
if ((minModulusLen > 0) && (modulusLen < (minModulusLen))) {
throw new InvalidKeyException( "RSA keys must be at least " +
minModulusLen + " bits long");
}
// Even though our policy file may allow this, we don't want
// either value (mod/exp) to be too big.
int maxLen = Math.min(maxModulusLen, MAX_MODLEN);
// If a RSAPrivateKey/RSAPublicKey, make sure the
// modulus len isn't too big.
if (modulusLen > maxLen) {
throw new InvalidKeyException(
"RSA keys must be no longer than " + maxLen + " bits");
}
// If a RSAPublicKey, make sure the exponent isn't too big.
if (restrictExpLen && (exponent != null) &&
(modulusLen > MAX_MODLEN_RESTRICT_EXP) &&
(exponent.bitLength() > MAX_RESTRICTED_EXPLEN)) {
throw new InvalidKeyException(
"RSA exponents can be no longer than " +
MAX_RESTRICTED_EXPLEN + " bits " +
" if modulus is greater than " +
MAX_MODLEN_RESTRICT_EXP + " bits");
}
}
/**
* Translate an RSA key into a SunRsaSign RSA key. If conversion is
* not possible, throw an InvalidKeyException.
* See also JCA doc.
*/
protected Key engineTranslateKey(Key key) throws InvalidKeyException {
if (key == null) {
throw new InvalidKeyException("Key must not be null");
}
String keyAlg = key.getAlgorithm();
if (keyAlg.equals("RSA") == false) {
throw new InvalidKeyException("Not an RSA key: " + keyAlg);
}
if (key instanceof PublicKey) {
return translatePublicKey((PublicKey)key);
} else if (key instanceof PrivateKey) {
return translatePrivateKey((PrivateKey)key);
} else {
throw new InvalidKeyException("Neither a public nor a private key");
}
}
// see JCA doc
protected PublicKey engineGeneratePublic(KeySpec keySpec)
throws InvalidKeySpecException {
try {
return generatePublic(keySpec);
} catch (InvalidKeySpecException e) {
throw e;
} catch (GeneralSecurityException e) {
throw new InvalidKeySpecException(e);
}
}
// see JCA doc
protected PrivateKey engineGeneratePrivate(KeySpec keySpec)
throws InvalidKeySpecException {
try {
return generatePrivate(keySpec);
} catch (InvalidKeySpecException e) {
throw e;
} catch (GeneralSecurityException e) {
throw new InvalidKeySpecException(e);
}
}
// internal implementation of translateKey() for public keys. See JCA doc
private PublicKey translatePublicKey(PublicKey key)
throws InvalidKeyException {
if (key instanceof RSAPublicKey) {
if (key instanceof RSAPublicKeyImpl) {
return key;
}
RSAPublicKey rsaKey = (RSAPublicKey)key;
try {
return new RSAPublicKeyImpl(
rsaKey.getModulus(),
rsaKey.getPublicExponent()
);
} catch (RuntimeException e) {
// catch providers that incorrectly implement RSAPublicKey
throw new InvalidKeyException("Invalid key", e);
}
} else if ("X.509".equals(key.getFormat())) {
byte[] encoded = key.getEncoded();
return new RSAPublicKeyImpl(encoded);
} else {
throw new InvalidKeyException("Public keys must be instance "
+ "of RSAPublicKey or have X.509 encoding");
}
}
// internal implementation of translateKey() for private keys. See JCA doc
private PrivateKey translatePrivateKey(PrivateKey key)
throws InvalidKeyException {
if (key instanceof RSAPrivateCrtKey) {
if (key instanceof RSAPrivateCrtKeyImpl) {
return key;
}
RSAPrivateCrtKey rsaKey = (RSAPrivateCrtKey)key;
try {
return new RSAPrivateCrtKeyImpl(
rsaKey.getModulus(),
rsaKey.getPublicExponent(),
rsaKey.getPrivateExponent(),
rsaKey.getPrimeP(),
rsaKey.getPrimeQ(),
rsaKey.getPrimeExponentP(),
rsaKey.getPrimeExponentQ(),
rsaKey.getCrtCoefficient()
);
} catch (RuntimeException e) {
// catch providers that incorrectly implement RSAPrivateCrtKey
throw new InvalidKeyException("Invalid key", e);
}
} else if (key instanceof RSAPrivateKey) {
if (key instanceof RSAPrivateKeyImpl) {
return key;
}
RSAPrivateKey rsaKey = (RSAPrivateKey)key;
try {
return new RSAPrivateKeyImpl(
rsaKey.getModulus(),
rsaKey.getPrivateExponent()
);
} catch (RuntimeException e) {
// catch providers that incorrectly implement RSAPrivateKey
throw new InvalidKeyException("Invalid key", e);
}
} else if ("PKCS#8".equals(key.getFormat())) {
byte[] encoded = key.getEncoded();
return RSAPrivateCrtKeyImpl.newKey(encoded);
} else {
throw new InvalidKeyException("Private keys must be instance "
+ "of RSAPrivate(Crt)Key or have PKCS#8 encoding");
}
}
// internal implementation of generatePublic. See JCA doc
private PublicKey generatePublic(KeySpec keySpec)
throws GeneralSecurityException {
if (keySpec instanceof X509EncodedKeySpec) {
X509EncodedKeySpec x509Spec = (X509EncodedKeySpec)keySpec;
return new RSAPublicKeyImpl(x509Spec.getEncoded());
} else if (keySpec instanceof RSAPublicKeySpec) {
RSAPublicKeySpec rsaSpec = (RSAPublicKeySpec)keySpec;
return new RSAPublicKeyImpl(
rsaSpec.getModulus(),
rsaSpec.getPublicExponent()
);
} else {
throw new InvalidKeySpecException("Only RSAPublicKeySpec "
+ "and X509EncodedKeySpec supported for RSA public keys");
}
}
// internal implementation of generatePrivate. See JCA doc
private PrivateKey generatePrivate(KeySpec keySpec)
throws GeneralSecurityException {
if (keySpec instanceof PKCS8EncodedKeySpec) {
PKCS8EncodedKeySpec pkcsSpec = (PKCS8EncodedKeySpec)keySpec;
return RSAPrivateCrtKeyImpl.newKey(pkcsSpec.getEncoded());
} else if (keySpec instanceof RSAPrivateCrtKeySpec) {
RSAPrivateCrtKeySpec rsaSpec = (RSAPrivateCrtKeySpec)keySpec;
return new RSAPrivateCrtKeyImpl(
rsaSpec.getModulus(),
rsaSpec.getPublicExponent(),
rsaSpec.getPrivateExponent(),
rsaSpec.getPrimeP(),
rsaSpec.getPrimeQ(),
rsaSpec.getPrimeExponentP(),
rsaSpec.getPrimeExponentQ(),
rsaSpec.getCrtCoefficient()
);
} else if (keySpec instanceof RSAPrivateKeySpec) {
RSAPrivateKeySpec rsaSpec = (RSAPrivateKeySpec)keySpec;
return new RSAPrivateKeyImpl(
rsaSpec.getModulus(),
rsaSpec.getPrivateExponent()
);
} else {
throw new InvalidKeySpecException("Only RSAPrivate(Crt)KeySpec "
+ "and PKCS8EncodedKeySpec supported for RSA private keys");
}
}
protected <T extends KeySpec> T engineGetKeySpec(Key key, Class<T> keySpec)
throws InvalidKeySpecException {
try {
// convert key to one of our keys
// this also verifies that the key is a valid RSA key and ensures
// that the encoding is X.509/PKCS#8 for public/private keys
key = engineTranslateKey(key);
} catch (InvalidKeyException e) {
throw new InvalidKeySpecException(e);
}
if (key instanceof RSAPublicKey) {
RSAPublicKey rsaKey = (RSAPublicKey)key;
if (rsaPublicKeySpecClass.isAssignableFrom(keySpec)) {
return (T) new RSAPublicKeySpec(
rsaKey.getModulus(),
rsaKey.getPublicExponent()
);
} else if (x509KeySpecClass.isAssignableFrom(keySpec)) {
return (T) new X509EncodedKeySpec(key.getEncoded());
} else {
throw new InvalidKeySpecException
("KeySpec must be RSAPublicKeySpec or "
+ "X509EncodedKeySpec for RSA public keys");
}
} else if (key instanceof RSAPrivateKey) {
if (pkcs8KeySpecClass.isAssignableFrom(keySpec)) {
return (T) new PKCS8EncodedKeySpec(key.getEncoded());
} else if (rsaPrivateCrtKeySpecClass.isAssignableFrom(keySpec)) {
if (key instanceof RSAPrivateCrtKey) {
RSAPrivateCrtKey crtKey = (RSAPrivateCrtKey)key;
return (T) new RSAPrivateCrtKeySpec(
crtKey.getModulus(),
crtKey.getPublicExponent(),
crtKey.getPrivateExponent(),
crtKey.getPrimeP(),
crtKey.getPrimeQ(),
crtKey.getPrimeExponentP(),
crtKey.getPrimeExponentQ(),
crtKey.getCrtCoefficient()
);
} else {
throw new InvalidKeySpecException
("RSAPrivateCrtKeySpec can only be used with CRT keys");
}
} else if (rsaPrivateKeySpecClass.isAssignableFrom(keySpec)) {
RSAPrivateKey rsaKey = (RSAPrivateKey)key;
return (T) new RSAPrivateKeySpec(
rsaKey.getModulus(),
rsaKey.getPrivateExponent()
);
} else {
throw new InvalidKeySpecException
("KeySpec must be RSAPrivate(Crt)KeySpec or "
+ "PKCS8EncodedKeySpec for RSA private keys");
}
} else {
// should not occur, caught in engineTranslateKey()
throw new InvalidKeySpecException("Neither public nor private key");
}
}
}