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Support for receiving arbitrary attachment types
// FREEBIE
This commit is contained in:
Moxie Marlinspike
@@ -16,213 +16,100 @@
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*/
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package org.thoughtcrime.securesms.crypto;
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import org.thoughtcrime.securesms.util.LimitedInputStream;
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import java.io.File;
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import java.io.FileInputStream;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.io.InputStream;
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import java.security.InvalidAlgorithmParameterException;
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import java.security.InvalidKeyException;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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import java.util.Arrays;
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import java.lang.System;
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import javax.crypto.BadPaddingException;
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import javax.crypto.Cipher;
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import javax.crypto.IllegalBlockSizeException;
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import javax.crypto.CipherInputStream;
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import javax.crypto.Mac;
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import javax.crypto.NoSuchPaddingException;
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import javax.crypto.ShortBufferException;
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import javax.crypto.spec.IvParameterSpec;
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import javax.crypto.spec.SecretKeySpec;
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import android.util.Log;
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/**
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* Class for streaming an encrypted MMS "part" off the disk.
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*
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* @author Moxie Marlinspike
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*/
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public class DecryptingPartInputStream extends FileInputStream {
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public class DecryptingPartInputStream {
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private static final String TAG = DecryptingPartInputStream.class.getSimpleName();
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private static final int IV_LENGTH = 16;
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private static final int MAC_LENGTH = 20;
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private Cipher cipher;
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private Mac mac;
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private boolean done;
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private long totalDataSize;
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private long totalRead;
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private byte[] overflowBuffer;
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public DecryptingPartInputStream(File file, MasterSecret masterSecret) throws FileNotFoundException {
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super(file);
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try {
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if (file.length() <= IV_LENGTH + MAC_LENGTH)
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throw new FileNotFoundException("Part shorter than crypto overhead!");
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done = false;
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mac = initializeMac(masterSecret.getMacKey());
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cipher = initializeCipher(masterSecret.getEncryptionKey());
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totalDataSize = file.length() - cipher.getBlockSize() - mac.getMacLength();
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totalRead = 0;
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} catch (InvalidKeyException ike) {
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Log.w(TAG, ike);
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throw new FileNotFoundException("Invalid key!");
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} catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException | NoSuchPaddingException e) {
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throw new AssertionError(e);
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} catch (IOException e) {
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Log.w(TAG, e);
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throw new FileNotFoundException("IOException while reading IV!");
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}
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}
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@Override
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public int read(byte[] buffer) throws IOException {
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return read(buffer, 0, buffer.length);
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}
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@Override
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public int read(byte[] buffer, int offset, int length) throws IOException {
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if (totalRead != totalDataSize)
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return readIncremental(buffer, offset, length);
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else if (!done)
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return readFinal(buffer, offset, length);
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else
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return -1;
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}
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@Override
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public boolean markSupported() {
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return false;
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}
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@Override
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public long skip(long byteCount) throws IOException {
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long skipped = 0L;
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while (skipped < byteCount) {
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byte[] buf = new byte[Math.min(4096, (int)(byteCount-skipped))];
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int read = read(buf);
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skipped += read;
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}
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return skipped;
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}
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private int readFinal(byte[] buffer, int offset, int length) throws IOException {
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try {
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int flourish = cipher.doFinal(buffer, offset);
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//mac.update(buffer, offset, flourish);
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byte[] ourMac = mac.doFinal();
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byte[] theirMac = new byte[mac.getMacLength()];
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readFully(theirMac);
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if (!Arrays.equals(ourMac, theirMac))
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throw new IOException("MAC doesn't match! Potential tampering?");
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done = true;
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return flourish;
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} catch (IllegalBlockSizeException e) {
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Log.w(TAG, e);
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throw new IOException("Illegal block size exception!");
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} catch (ShortBufferException e) {
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Log.w(TAG, e);
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throw new IOException("Short buffer exception!");
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} catch (BadPaddingException e) {
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Log.w(TAG, e);
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throw new IOException("Bad padding exception!");
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}
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}
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private int readIncremental(byte[] buffer, int offset, int length) throws IOException {
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int readLength = 0;
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if (null != overflowBuffer) {
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if (overflowBuffer.length > length) {
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System.arraycopy(overflowBuffer, 0, buffer, offset, length);
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overflowBuffer = Arrays.copyOfRange(overflowBuffer, length, overflowBuffer.length);
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return length;
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} else if (overflowBuffer.length == length) {
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System.arraycopy(overflowBuffer, 0, buffer, offset, length);
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overflowBuffer = null;
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return length;
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} else {
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System.arraycopy(overflowBuffer, 0, buffer, offset, overflowBuffer.length);
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readLength += overflowBuffer.length;
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offset += readLength;
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length -= readLength;
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overflowBuffer = null;
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}
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}
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if (length + totalRead > totalDataSize)
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length = (int)(totalDataSize - totalRead);
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byte[] internalBuffer = new byte[length];
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int read = super.read(internalBuffer, 0, internalBuffer.length <= cipher.getBlockSize() ? internalBuffer.length : internalBuffer.length - cipher.getBlockSize());
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totalRead += read;
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try {
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mac.update(internalBuffer, 0, read);
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int outputLen = cipher.getOutputSize(read);
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if (outputLen <= length) {
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readLength += cipher.update(internalBuffer, 0, read, buffer, offset);
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return readLength;
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}
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byte[] transientBuffer = new byte[outputLen];
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outputLen = cipher.update(internalBuffer, 0, read, transientBuffer, 0);
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if (outputLen <= length) {
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System.arraycopy(transientBuffer, 0, buffer, offset, outputLen);
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readLength += outputLen;
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} else {
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System.arraycopy(transientBuffer, 0, buffer, offset, length);
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overflowBuffer = Arrays.copyOfRange(transientBuffer, length, outputLen);
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readLength += length;
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}
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return readLength;
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} catch (ShortBufferException e) {
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throw new AssertionError(e);
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}
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}
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private Mac initializeMac(SecretKeySpec key) throws NoSuchAlgorithmException, InvalidKeyException {
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Mac hmac = Mac.getInstance("HmacSHA1");
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hmac.init(key);
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return hmac;
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}
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private Cipher initializeCipher(SecretKeySpec key)
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throws InvalidKeyException, InvalidAlgorithmParameterException,
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NoSuchAlgorithmException, NoSuchPaddingException, IOException
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public static InputStream createFor(MasterSecret masterSecret, File file)
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throws IOException
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{
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Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
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IvParameterSpec iv = readIv(cipher.getBlockSize());
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cipher.init(Cipher.DECRYPT_MODE, key, iv);
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try {
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if (file.length() <= IV_LENGTH + MAC_LENGTH) {
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throw new IOException("File too short");
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}
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return cipher;
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verifyMac(masterSecret, file);
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FileInputStream fileStream = new FileInputStream(file);
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byte[] ivBytes = new byte[IV_LENGTH];
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readFully(fileStream, ivBytes);
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Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
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IvParameterSpec iv = new IvParameterSpec(ivBytes);
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cipher.init(Cipher.DECRYPT_MODE, masterSecret.getEncryptionKey(), iv);
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return new CipherInputStream(new LimitedInputStream(fileStream, file.length() - MAC_LENGTH - IV_LENGTH), cipher);
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} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException | InvalidAlgorithmParameterException e) {
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throw new AssertionError(e);
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}
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}
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private IvParameterSpec readIv(int size) throws IOException {
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byte[] iv = new byte[size];
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readFully(iv);
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private static void verifyMac(MasterSecret masterSecret, File file) throws IOException {
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Mac mac = initializeMac(masterSecret.getMacKey());
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FileInputStream macStream = new FileInputStream(file);
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InputStream dataStream = new LimitedInputStream(new FileInputStream(file), file.length() - MAC_LENGTH);
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byte[] theirMac = new byte[MAC_LENGTH];
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mac.update(iv);
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return new IvParameterSpec(iv);
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if (macStream.skip(file.length() - MAC_LENGTH) != file.length() - MAC_LENGTH) {
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throw new IOException("Unable to seek");
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}
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readFully(macStream, theirMac);
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byte[] buffer = new byte[4096];
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int read;
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while ((read = dataStream.read(buffer)) != -1) {
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mac.update(buffer, 0, read);
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}
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byte[] ourMac = mac.doFinal();
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if (!MessageDigest.isEqual(ourMac, theirMac)) {
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throw new IOException("Bad MAC");
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}
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macStream.close();
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dataStream.close();
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}
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private void readFully(byte[] buffer) throws IOException {
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private static Mac initializeMac(SecretKeySpec key) {
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try {
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Mac hmac = Mac.getInstance("HmacSHA1");
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hmac.init(key);
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return hmac;
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} catch (NoSuchAlgorithmException | InvalidKeyException e) {
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throw new AssertionError(e);
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}
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}
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private static void readFully(InputStream in, byte[] buffer) throws IOException {
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int offset = 0;
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for (;;) {
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int read = super.read(buffer, offset, buffer.length-offset);
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int read = in.read(buffer, offset, buffer.length-offset);
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if (read + offset < buffer.length) offset += read;
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else return;
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