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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* 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,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package com.sun.crypto.provider;
import java.util.Arrays;
import java.util.Locale;
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.BadPaddingException;
/**
* This class represents the symmetric algorithms in its various modes
* (<code>ECB</code>, <code>CFB</code>, <code>OFB</code>, <code>CBC</code>,
* <code>PCBC</code>, <code>CTR</code>, and <code>CTS</code>) and
* padding schemes (<code>PKCS5Padding</code>, <code>NoPadding</code>,
* <code>ISO10126Padding</code>).
*
* @author Gigi Ankeny
* @author Jan Luehe
* @see ElectronicCodeBook
* @see CipherFeedback
* @see OutputFeedback
* @see CipherBlockChaining
* @see PCBC
* @see CounterMode
* @see CipherTextStealing
*/
final class CipherCore {
/*
* internal buffer
*/
private byte[] buffer = null;
/*
* block size of cipher in bytes
*/
private int blockSize = 0;
/*
* unit size (number of input bytes that can be processed at a time)
*/
private int unitBytes = 0;
/*
* index of the content size left in the buffer
*/
private int buffered = 0;
/*
* minimum number of bytes in the buffer required for
* FeedbackCipher.encryptFinal()/decryptFinal() call.
* update() must buffer this many bytes before starting
* to encrypt/decrypt data.
* currently, only the following cases have non-zero values:
* 1) CTS mode - due to its special handling on the last two blocks
* (the last one may be incomplete).
* 2) GCM mode + decryption - due to its trailing tag bytes
*/
private int minBytes = 0;
/*
* number of bytes needed to make the total input length a multiple
* of the blocksize (this is used in feedback mode, when the number of
* input bytes that are processed at a time is different from the block
* size)
*/
private int diffBlocksize = 0;
/*
* padding class
*/
private Padding padding = null;
/*
* internal cipher engine
*/
private FeedbackCipher cipher = null;
/*
* the cipher mode
*/
private int cipherMode = ECB_MODE;
/*
* are we encrypting or decrypting?
*/
private boolean decrypting = false;
/*
* Block Mode constants
*/
private static final int ECB_MODE = 0;
private static final int CBC_MODE = 1;
private static final int CFB_MODE = 2;
private static final int OFB_MODE = 3;
private static final int PCBC_MODE = 4;
private static final int CTR_MODE = 5;
private static final int CTS_MODE = 6;
private static final int GCM_MODE = 7;
/*
* variables used for performing the GCM (key+iv) uniqueness check.
* To use GCM mode safely, the cipher object must be re-initialized
* with a different combination of key + iv values for each
* encryption operation. However, checking all past key + iv values
* isn't feasible. Thus, we only do a per-instance check of the
* key + iv values used in previous encryption.
* For decryption operations, no checking is necessary.
* NOTE: this key+iv check have to be done inside CipherCore class
* since CipherCore class buffers potential tag bytes in GCM mode
* and may not call GaloisCounterMode when there isn't sufficient
* input to process.
*/
private boolean requireReinit = false;
private byte[] lastEncKey = null;
private byte[] lastEncIv = null;
/**
* Creates an instance of CipherCore with default ECB mode and
* PKCS5Padding.
*/
CipherCore(SymmetricCipher impl, int blkSize) {
blockSize = blkSize;
unitBytes = blkSize;
diffBlocksize = blkSize;
/*
* The buffer should be usable for all cipher mode and padding
* schemes. Thus, it has to be at least (blockSize+1) for CTS.
* In decryption mode, it also hold the possible padding block.
*/
buffer = new byte[blockSize*2];
// set mode and padding
cipher = new ElectronicCodeBook(impl);
padding = new PKCS5Padding(blockSize);
}
/**
* Sets the mode of this cipher.
*
* @param mode the cipher mode
*
* @exception NoSuchAlgorithmException if the requested cipher mode does
* not exist for this cipher
*/
void setMode(String mode) throws NoSuchAlgorithmException {
if (mode == null)
throw new NoSuchAlgorithmException("null mode");
String modeUpperCase = mode.toUpperCase(Locale.ENGLISH);
if (modeUpperCase.equals("ECB")) {
return;
}
SymmetricCipher rawImpl = cipher.getEmbeddedCipher();
if (modeUpperCase.equals("CBC")) {
cipherMode = CBC_MODE;
cipher = new CipherBlockChaining(rawImpl);
} else if (modeUpperCase.equals("CTS")) {
cipherMode = CTS_MODE;
cipher = new CipherTextStealing(rawImpl);
minBytes = blockSize+1;
padding = null;
} else if (modeUpperCase.equals("CTR")) {
cipherMode = CTR_MODE;
cipher = new CounterMode(rawImpl);
unitBytes = 1;
padding = null;
} else if (modeUpperCase.startsWith("GCM")) {
// can only be used for block ciphers w/ 128-bit block size
if (blockSize != 16) {
throw new NoSuchAlgorithmException
("GCM mode can only be used for AES cipher");
}
cipherMode = GCM_MODE;
cipher = new GaloisCounterMode(rawImpl);
padding = null;
} else if (modeUpperCase.startsWith("CFB")) {
cipherMode = CFB_MODE;
unitBytes = getNumOfUnit(mode, "CFB".length(), blockSize);
cipher = new CipherFeedback(rawImpl, unitBytes);
} else if (modeUpperCase.startsWith("OFB")) {
cipherMode = OFB_MODE;
unitBytes = getNumOfUnit(mode, "OFB".length(), blockSize);
cipher = new OutputFeedback(rawImpl, unitBytes);
} else if (modeUpperCase.equals("PCBC")) {
cipherMode = PCBC_MODE;
cipher = new PCBC(rawImpl);
}
else {
throw new NoSuchAlgorithmException("Cipher mode: " + mode
+ " not found");
}
}
private static int getNumOfUnit(String mode, int offset, int blockSize)
throws NoSuchAlgorithmException {
int result = blockSize; // use blockSize as default value
if (mode.length() > offset) {
int numInt;
try {
Integer num = Integer.valueOf(mode.substring(offset));
numInt = num.intValue();
result = numInt >> 3;
} catch (NumberFormatException e) {
throw new NoSuchAlgorithmException
("Algorithm mode: " + mode + " not implemented");
}
if ((numInt % 8 != 0) || (result > blockSize)) {
throw new NoSuchAlgorithmException
("Invalid algorithm mode: " + mode);
}
}
return result;
}
/**
* Sets the padding mechanism of this cipher.
*
* @param padding the padding mechanism
*
* @exception NoSuchPaddingException if the requested padding mechanism
* does not exist
*/
void setPadding(String paddingScheme)
throws NoSuchPaddingException
{
if (paddingScheme == null) {
throw new NoSuchPaddingException("null padding");
}
if (paddingScheme.equalsIgnoreCase("NoPadding")) {
padding = null;
} else if (paddingScheme.equalsIgnoreCase("ISO10126Padding")) {
padding = new ISO10126Padding(blockSize);
} else if (!paddingScheme.equalsIgnoreCase("PKCS5Padding")) {
throw new NoSuchPaddingException("Padding: " + paddingScheme
+ " not implemented");
}
if ((padding != null) &&
((cipherMode == CTR_MODE) || (cipherMode == CTS_MODE)
|| (cipherMode == GCM_MODE))) {
padding = null;
String modeStr = null;
switch (cipherMode) {
case CTR_MODE:
modeStr = "CTR";
break;
case GCM_MODE:
modeStr = "GCM";
break;
case CTS_MODE:
modeStr = "CTS";
break;
default:
// should never happen
}
if (modeStr != null) {
throw new NoSuchPaddingException
(modeStr + " mode must be used with NoPadding");
}
}
}
/**
* Returns the length in bytes that an output buffer would need to be in
* order to hold the result of the next <code>update</code> or
* <code>doFinal</code> operation, given the input length
* <code>inputLen</code> (in bytes).
*
* <p>This call takes into account any unprocessed (buffered) data from a
* previous <code>update</code> call, padding, and AEAD tagging.
*
* <p>The actual output length of the next <code>update</code> or
* <code>doFinal</code> call may be smaller than the length returned by
* this method.
*
* @param inputLen the input length (in bytes)
*
* @return the required output buffer size (in bytes)
*/
int getOutputSize(int inputLen) {
// estimate based on the maximum
return getOutputSizeByOperation(inputLen, true);
}
private int getOutputSizeByOperation(int inputLen, boolean isDoFinal) {
int totalLen = buffered + inputLen + cipher.getBufferedLength();
switch (cipherMode) {
case GCM_MODE:
if (isDoFinal) {
int tagLen = ((GaloisCounterMode) cipher).getTagLen();
if (!decrypting) {
totalLen += tagLen;
} else {
totalLen -= tagLen;
}
}
if (totalLen < 0) {
totalLen = 0;
}
break;
default:
if (padding != null && !decrypting) {
if (unitBytes != blockSize) {
if (totalLen < diffBlocksize) {
totalLen = diffBlocksize;
} else {
int residue = (totalLen - diffBlocksize) % blockSize;
totalLen += (blockSize - residue);
}
} else {
totalLen += padding.padLength(totalLen);
}
}
break;
}
return totalLen;
}
/**
* Returns the initialization vector (IV) in a new buffer.
*
* <p>This is useful in the case where a random IV has been created
* (see <a href = "#init">init</a>),
* or in the context of password-based encryption or
* decryption, where the IV is derived from a user-provided password.
*
* @return the initialization vector in a new buffer, or null if the
* underlying algorithm does not use an IV, or if the IV has not yet
* been set.
*/
byte[] getIV() {
byte[] iv = cipher.getIV();
return (iv == null) ? null : iv.clone();
}
/**
* Returns the parameters used with this cipher.
*
* <p>The returned parameters may be the same that were used to initialize
* this cipher, or may contain the default set of parameters or a set of
* randomly generated parameters used by the underlying cipher
* implementation (provided that the underlying cipher implementation
* uses a default set of parameters or creates new parameters if it needs
* parameters but was not initialized with any).
*
* @return the parameters used with this cipher, or null if this cipher
* does not use any parameters.
*/
AlgorithmParameters getParameters(String algName) {
if (cipherMode == ECB_MODE) {
return null;
}
AlgorithmParameters params = null;
AlgorithmParameterSpec spec;
byte[] iv = getIV();
if (iv == null) {
// generate spec using default value
if (cipherMode == GCM_MODE) {
iv = new byte[GaloisCounterMode.DEFAULT_IV_LEN];
} else {
iv = new byte[blockSize];
}
SunJCE.getRandom().nextBytes(iv);
}
if (cipherMode == GCM_MODE) {
algName = "GCM";
spec = new GCMParameterSpec
(((GaloisCounterMode) cipher).getTagLen()*8, iv);
} else {
if (algName.equals("RC2")) {
RC2Crypt rawImpl = (RC2Crypt) cipher.getEmbeddedCipher();
spec = new RC2ParameterSpec
(rawImpl.getEffectiveKeyBits(), iv);
} else {
spec = new IvParameterSpec(iv);
}
}
try {
params = AlgorithmParameters.getInstance(algName,
SunJCE.getInstance());
params.init(spec);
} catch (NoSuchAlgorithmException nsae) {
// should never happen
throw new RuntimeException("Cannot find " + algName +
" AlgorithmParameters implementation in SunJCE provider");
} catch (InvalidParameterSpecException ipse) {
// should never happen
throw new RuntimeException(spec.getClass() + " not supported");
}
return params;
}
/**
* Initializes this cipher with a key and a source of randomness.
*
* <p>The cipher is initialized for one of the following four operations:
* encryption, decryption, key wrapping or key unwrapping, depending on
* the value of <code>opmode</code>.
*
* <p>If this cipher requires an initialization vector (IV), it will get
* it from <code>random</code>.
* This behaviour should only be used in encryption or key wrapping
* mode, however.
* When initializing a cipher that requires an IV for decryption or
* key unwrapping, the IV
* (same IV that was used for encryption or key wrapping) must be provided
* explicitly as a
* parameter, in order to get the correct result.
*
* <p>This method also cleans existing buffer and other related state
* information.
*
* @param opmode the operation mode of this cipher (this is one of
* the following:
* <code>ENCRYPT_MODE</code>, <code>DECRYPT_MODE</code>,
* <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>)
* @param key the secret key
* @param random the source of randomness
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher
*/
void init(int opmode, Key key, SecureRandom random)
throws InvalidKeyException {
try {
init(opmode, key, (AlgorithmParameterSpec)null, random);
} catch (InvalidAlgorithmParameterException e) {
throw new InvalidKeyException(e.getMessage());
}
}
/**
* Initializes this cipher with a key, a set of
* algorithm parameters, and a source of randomness.
*
* <p>The cipher is initialized for one of the following four operations:
* encryption, decryption, key wrapping or key unwrapping, depending on
* the value of <code>opmode</code>.
*
* <p>If this cipher (including its underlying feedback or padding scheme)
* requires any random bytes, it will get them from <code>random</code>.
*
* @param opmode the operation mode of this cipher (this is one of
* the following:
* <code>ENCRYPT_MODE</code>, <code>DECRYPT_MODE</code>,
* <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>)
* @param key the encryption key
* @param params the algorithm parameters
* @param random the source of randomness
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this cipher
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this cipher
*/
void init(int opmode, Key key, AlgorithmParameterSpec params,
SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException {
decrypting = (opmode == Cipher.DECRYPT_MODE)
|| (opmode == Cipher.UNWRAP_MODE);
byte[] keyBytes = getKeyBytes(key);
int tagLen = -1;
byte[] ivBytes = null;
if (params != null) {
if (cipherMode == GCM_MODE) {
if (params instanceof GCMParameterSpec) {
tagLen = ((GCMParameterSpec)params).getTLen();
if (tagLen < 96 || tagLen > 128 || ((tagLen & 0x07) != 0)) {
throw new InvalidAlgorithmParameterException
("Unsupported TLen value; must be one of " +
"{128, 120, 112, 104, 96}");
}
tagLen = tagLen >> 3;
ivBytes = ((GCMParameterSpec)params).getIV();
} else {
throw new InvalidAlgorithmParameterException
("Unsupported parameter: " + params);
}
} else {
if (params instanceof IvParameterSpec) {
ivBytes = ((IvParameterSpec)params).getIV();
if ((ivBytes == null) || (ivBytes.length != blockSize)) {
throw new InvalidAlgorithmParameterException
("Wrong IV length: must be " + blockSize +
" bytes long");
}
} else if (params instanceof RC2ParameterSpec) {
ivBytes = ((RC2ParameterSpec)params).getIV();
if ((ivBytes != null) && (ivBytes.length != blockSize)) {
throw new InvalidAlgorithmParameterException
("Wrong IV length: must be " + blockSize +
" bytes long");
}
} else {
throw new InvalidAlgorithmParameterException
("Unsupported parameter: " + params);
}
}
}
if (cipherMode == ECB_MODE) {
if (ivBytes != null) {
throw new InvalidAlgorithmParameterException
("ECB mode cannot use IV");
}
} else if (ivBytes == null) {
if (decrypting) {
throw new InvalidAlgorithmParameterException("Parameters "
+ "missing");
}
if (random == null) {
random = SunJCE.getRandom();
}
if (cipherMode == GCM_MODE) {
ivBytes = new byte[GaloisCounterMode.DEFAULT_IV_LEN];
} else {
ivBytes = new byte[blockSize];
}
random.nextBytes(ivBytes);
}
buffered = 0;
diffBlocksize = blockSize;
String algorithm = key.getAlgorithm();
// GCM mode needs additional handling
if (cipherMode == GCM_MODE) {
if(tagLen == -1) {
tagLen = GaloisCounterMode.DEFAULT_TAG_LEN;
}
if (decrypting) {
minBytes = tagLen;
} else {
// check key+iv for encryption in GCM mode
requireReinit =
Arrays.equals(ivBytes, lastEncIv) &&
Arrays.equals(keyBytes, lastEncKey);
if (requireReinit) {
throw new InvalidAlgorithmParameterException
("Cannot reuse iv for GCM encryption");
}
lastEncIv = ivBytes;
lastEncKey = keyBytes;
}
((GaloisCounterMode) cipher).init
(decrypting, algorithm, keyBytes, ivBytes, tagLen);
} else {
cipher.init(decrypting, algorithm, keyBytes, ivBytes);
}
// skip checking key+iv from now on until after doFinal()
requireReinit = false;
}
void init(int opmode, Key key, AlgorithmParameters params,
SecureRandom random)
throws InvalidKeyException, InvalidAlgorithmParameterException {
AlgorithmParameterSpec spec = null;
String paramType = null;
if (params != null) {
try {
if (cipherMode == GCM_MODE) {
paramType = "GCM";
spec = params.getParameterSpec(GCMParameterSpec.class);
} else {
// NOTE: RC2 parameters are always handled through
// init(..., AlgorithmParameterSpec,...) method, so
// we can assume IvParameterSpec type here.
paramType = "IV";
spec = params.getParameterSpec(IvParameterSpec.class);
}
} catch (InvalidParameterSpecException ipse) {
throw new InvalidAlgorithmParameterException
("Wrong parameter type: " + paramType + " expected");
}
}
init(opmode, key, spec, random);
}
/**
* Return the key bytes of the specified key. Throw an InvalidKeyException
* if the key is not usable.
*/
static byte[] getKeyBytes(Key key) throws InvalidKeyException {
if (key == null) {
throw new InvalidKeyException("No key given");
}
// note: key.getFormat() may return null
if (!"RAW".equalsIgnoreCase(key.getFormat())) {
throw new InvalidKeyException("Wrong format: RAW bytes needed");
}
byte[] keyBytes = key.getEncoded();
if (keyBytes == null) {
throw new InvalidKeyException("RAW key bytes missing");
}
return keyBytes;
}
/**
* Continues a multiple-part encryption or decryption operation
* (depending on how this cipher was initialized), processing another data
* part.
*
* <p>The first <code>inputLen</code> bytes in the <code>input</code>
* buffer, starting at <code>inputOffset</code>, are processed, and the
* result is stored in a new buffer.
*
* @param input the input buffer
* @param inputOffset the offset in <code>input</code> where the input
* starts
* @param inputLen the input length
*
* @return the new buffer with the result
*
* @exception IllegalStateException if this cipher is in a wrong state
* (e.g., has not been initialized)
*/
byte[] update(byte[] input, int inputOffset, int inputLen) {
if (requireReinit) {
throw new IllegalStateException
("Must use either different key or iv for GCM encryption");
}
byte[] output = null;
try {
output = new byte[getOutputSizeByOperation(inputLen, false)];
int len = update(input, inputOffset, inputLen, output,
0);
if (len == output.length) {
return output;
} else {
return Arrays.copyOf(output, len);
}
} catch (ShortBufferException e) {
// should never happen
throw new ProviderException("Unexpected exception", e);
}
}
/**
* Continues a multiple-part encryption or decryption operation
* (depending on how this cipher was initialized), processing another data
* part.
*
* <p>The first <code>inputLen</code> bytes in the <code>input</code>
* buffer, starting at <code>inputOffset</code>, are processed, and the
* result is stored in the <code>output</code> buffer, starting at
* <code>outputOffset</code>.
*
* @param input the input buffer
* @param inputOffset the offset in <code>input</code> where the input
* starts
* @param inputLen the input length
* @param output the buffer for the result
* @param outputOffset the offset in <code>output</code> where the result
* is stored
*
* @return the number of bytes stored in <code>output</code>
*
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
*/
int update(byte[] input, int inputOffset, int inputLen, byte[] output,
int outputOffset) throws ShortBufferException {
if (requireReinit) {
throw new IllegalStateException
("Must use either different key or iv for GCM encryption");
}
// figure out how much can be sent to crypto function
int len = buffered + inputLen - minBytes;
if (padding != null && decrypting) {
// do not include the padding bytes when decrypting
len -= blockSize;
}
// do not count the trailing bytes which do not make up a unit
len = (len > 0 ? (len - (len%unitBytes)) : 0);
// check output buffer capacity
if ((output == null) ||
((output.length - outputOffset) < len)) {
throw new ShortBufferException("Output buffer must be "
+ "(at least) " + len
+ " bytes long");
}
int outLen = 0;
if (len != 0) { // there is some work to do
if (len <= buffered) {
// all to-be-processed data are from 'buffer'
if (decrypting) {
outLen = cipher.decrypt(buffer, 0, len, output, outputOffset);
} else {
outLen = cipher.encrypt(buffer, 0, len, output, outputOffset);
}
buffered -= len;
if (buffered != 0) {
System.arraycopy(buffer, len, buffer, 0, buffered);
}
} else { // len > buffered
if ((input != output) && (buffered == 0)) {
// all to-be-processed data are from 'input'
// however, note that if 'input' and 'output' are the same,
// then they can't be passed directly to the underlying cipher
// engine operations as data may be overwritten before they
// are read.
if (decrypting) {
outLen = cipher.decrypt(input, inputOffset, len, output, outputOffset);
} else {
outLen = cipher.encrypt(input, inputOffset, len, output, outputOffset);
}
inputOffset += len;
inputLen -= len;
} else {
// assemble the data using both 'buffer' and 'input'
byte[] in = new byte[len];
int inConsumed = len - buffered;
if (buffered != 0) {
System.arraycopy(buffer, 0, in, 0, buffered);
buffered = 0;
}
if (inConsumed != 0) {
System.arraycopy(input, inputOffset, in, len - inConsumed, inConsumed);
inputOffset += inConsumed;
inputLen -= inConsumed;
}
if (decrypting) {
outLen = cipher.decrypt(in, 0, len, output, outputOffset);
} else {
outLen = cipher.encrypt(in, 0, len, output, outputOffset);
}
}
}
// Let's keep track of how many bytes are needed to make
// the total input length a multiple of blocksize when
// padding is applied
if (unitBytes != blockSize) {
if (len < diffBlocksize) {
diffBlocksize -= len;
} else {
diffBlocksize = blockSize -
((len - diffBlocksize) % blockSize);
}
}
}
// Store remaining input into 'buffer' again
if (inputLen > 0) {
System.arraycopy(input, inputOffset, buffer, buffered,
inputLen);
buffered += inputLen;
}
return outLen;
}
/**
* Encrypts or decrypts data in a single-part operation,
* or finishes a multiple-part operation.
* The data is encrypted or decrypted, depending on how this cipher was
* initialized.
*
* <p>The first <code>inputLen</code> bytes in the <code>input</code>
* buffer, starting at <code>inputOffset</code>, and any input bytes that
* may have been buffered during a previous <code>update</code> operation,
* are processed, with padding (if requested) being applied.
* The result is stored in a new buffer.
*
* <p>The cipher is reset to its initial state (uninitialized) after this
* call.
*
* @param input the input buffer
* @param inputOffset the offset in <code>input</code> where the input
* starts
* @param inputLen the input length
*
* @return the new buffer with the result
*
* @exception IllegalBlockSizeException if this cipher is a block cipher,
* no padding has been requested (only in encryption mode), and the total
* input length of the data processed by this cipher is not a multiple of
* block size
* @exception BadPaddingException if this cipher is in decryption mode,
* and (un)padding has been requested, but the decrypted data is not
* bounded by the appropriate padding bytes
*/
byte[] doFinal(byte[] input, int inputOffset, int inputLen)
throws IllegalBlockSizeException, BadPaddingException {
byte[] output = null;
try {
output = new byte[getOutputSizeByOperation(inputLen, true)];
int len = doFinal(input, inputOffset, inputLen, output, 0);
if (len < output.length) {
return Arrays.copyOf(output, len);
} else {
return output;
}
} catch (ShortBufferException e) {
// never thrown
throw new ProviderException("Unexpected exception", e);
}
}
/**
* Encrypts or decrypts data in a single-part operation,
* or finishes a multiple-part operation.
* The data is encrypted or decrypted, depending on how this cipher was
* initialized.
*
* <p>The first <code>inputLen</code> bytes in the <code>input</code>
* buffer, starting at <code>inputOffset</code>, and any input bytes that
* may have been buffered during a previous <code>update</code> operation,
* are processed, with padding (if requested) being applied.
* The result is stored in the <code>output</code> buffer, starting at
* <code>outputOffset</code>.
*
* <p>The cipher is reset to its initial state (uninitialized) after this
* call.
*
* @param input the input buffer
* @param inputOffset the offset in <code>input</code> where the input
* starts
* @param inputLen the input length
* @param output the buffer for the result
* @param outputOffset the offset in <code>output</code> where the result
* is stored
*
* @return the number of bytes stored in <code>output</code>
*
* @exception IllegalBlockSizeException if this cipher is a block cipher,
* no padding has been requested (only in encryption mode), and the total
* input length of the data processed by this cipher is not a multiple of
* block size
* @exception ShortBufferException if the given output buffer is too small
* to hold the result
* @exception BadPaddingException if this cipher is in decryption mode,
* and (un)padding has been requested, but the decrypted data is not
* bounded by the appropriate padding bytes
*/
int doFinal(byte[] input, int inputOffset, int inputLen, byte[] output,
int outputOffset)
throws IllegalBlockSizeException, ShortBufferException,
BadPaddingException {
if (requireReinit) {
throw new IllegalStateException
("Must use either different key or iv for GCM encryption");
}
int estOutSize = getOutputSizeByOperation(inputLen, true);
// check output buffer capacity.
// if we are decrypting with padding applied, we can perform this
// check only after we have determined how many padding bytes there
// are.
int outputCapacity = output.length - outputOffset;
int minOutSize = (decrypting? (estOutSize - blockSize):estOutSize);
if ((output == null) || (outputCapacity < minOutSize)) {
throw new ShortBufferException("Output buffer must be "
+ "(at least) " + minOutSize + " bytes long");
}
// calculate total input length
int len = buffered + inputLen;
// calculate padding length
int totalLen = len + cipher.getBufferedLength();
int paddingLen = 0;
// will the total input length be a multiple of blockSize?
if (unitBytes != blockSize) {
if (totalLen < diffBlocksize) {
paddingLen = diffBlocksize - totalLen;
} else {
paddingLen = blockSize -
((totalLen - diffBlocksize) % blockSize);
}
} else if (padding != null) {
paddingLen = padding.padLength(totalLen);
}
if (decrypting && (padding != null) &&
(paddingLen > 0) && (paddingLen != blockSize)) {
throw new IllegalBlockSizeException
("Input length must be multiple of " + blockSize +
" when decrypting with padded cipher");
}
/*
* prepare the final input, assemble a new buffer if any
* of the following is true:
* - 'input' and 'output' are the same buffer
* - there are internally buffered bytes
* - doing encryption and padding is needed
*/
byte[] finalBuf = input;
int finalOffset = inputOffset;
int finalBufLen = inputLen;
if ((input == output) || (buffered != 0) ||
(!decrypting && padding != null)) {
if (decrypting || padding == null) {
paddingLen = 0;
}
finalBuf = new byte[len + paddingLen];
finalOffset = 0;
if (buffered != 0) {
System.arraycopy(buffer, 0, finalBuf, 0, buffered);
}
if (inputLen != 0) {
System.arraycopy(input, inputOffset, finalBuf,
buffered, inputLen);
}
if (paddingLen != 0) {
padding.padWithLen(finalBuf, (buffered+inputLen), paddingLen);
}
finalBufLen = finalBuf.length;
}
int outLen = 0;
if (decrypting) {
// if the size of specified output buffer is less than
// the length of the cipher text, then the current
// content of cipher has to be preserved in order for
// users to retry the call with a larger buffer in the
// case of ShortBufferException.
if (outputCapacity < estOutSize) {
cipher.save();
}
// create temporary output buffer so that only "real"
// data bytes are passed to user's output buffer.
byte[] outWithPadding = new byte[estOutSize];
outLen = finalNoPadding(finalBuf, finalOffset, outWithPadding,
0, finalBufLen);
if (padding != null) {
int padStart = padding.unpad(outWithPadding, 0, outLen);
if (padStart < 0) {
throw new BadPaddingException("Given final block not "
+ "properly padded");
}
outLen = padStart;
}
if (outputCapacity < outLen) {
// restore so users can retry with a larger buffer
cipher.restore();
throw new ShortBufferException("Output buffer too short: "
+ (outputCapacity)
+ " bytes given, " + outLen
+ " bytes needed");
}
// copy the result into user-supplied output buffer
System.arraycopy(outWithPadding, 0, output, outputOffset, outLen);
} else { // encrypting
try {
outLen = finalNoPadding(finalBuf, finalOffset, output,
outputOffset, finalBufLen);
} finally {
// reset after doFinal() for GCM encryption
requireReinit = (cipherMode == GCM_MODE);
}
}
buffered = 0;
diffBlocksize = blockSize;
if (cipherMode != ECB_MODE) {
cipher.reset();
}
return outLen;
}
private int finalNoPadding(byte[] in, int inOfs, byte[] out, int outOfs,
int len)
throws IllegalBlockSizeException, AEADBadTagException,
ShortBufferException {
if ((cipherMode != GCM_MODE) && (in == null || len == 0)) {
return 0;
}
if ((cipherMode != CFB_MODE) && (cipherMode != OFB_MODE) &&
(cipherMode != GCM_MODE) &&
((len % unitBytes) != 0) && (cipherMode != CTS_MODE)) {
if (padding != null) {
throw new IllegalBlockSizeException
("Input length (with padding) not multiple of " +
unitBytes + " bytes");
} else {
throw new IllegalBlockSizeException
("Input length not multiple of " + unitBytes
+ " bytes");
}
}
int outLen = 0;
if (decrypting) {
outLen = cipher.decryptFinal(in, inOfs, len, out, outOfs);
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