Include the frame number in the header.

This ensures the frame number is covered by the MAC, cleanly
separating encryption from authentication (previously we depended on
the encryption layer to garble frames if they were reordered).
This commit is contained in:
akwizgran
2011-12-02 13:37:44 +00:00
parent 14d5e6fe64
commit 51d58fadad
9 changed files with 144 additions and 80 deletions

View File

@@ -7,6 +7,9 @@ public interface TransportConstants {
*/ */
static final int MAX_FRAME_LENGTH = 65536; // 2^16, 64 KiB static final int MAX_FRAME_LENGTH = 65536; // 2^16, 64 KiB
/** The length of the frame header in bytes. */
static final int FRAME_HEADER_LENGTH = 8;
/** /**
* The length in bytes of the pseudo-random tag that uniquely identifies a * The length in bytes of the pseudo-random tag that uniquely identifies a
* connection. * connection.

View File

@@ -1,5 +1,6 @@
package net.sf.briar.transport; package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH; import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED; import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
@@ -11,11 +12,10 @@ import java.security.InvalidKeyException;
import java.util.Arrays; import java.util.Arrays;
import javax.crypto.Mac; import javax.crypto.Mac;
import net.sf.briar.api.crypto.ErasableKey;
import net.sf.briar.api.FormatException; import net.sf.briar.api.FormatException;
import net.sf.briar.api.crypto.ErasableKey;
import net.sf.briar.api.transport.ConnectionReader; import net.sf.briar.api.transport.ConnectionReader;
import net.sf.briar.util.ByteUtils;
class ConnectionReaderImpl extends FilterInputStream class ConnectionReaderImpl extends FilterInputStream
implements ConnectionReader { implements ConnectionReader {
@@ -41,8 +41,9 @@ implements ConnectionReader {
throw new IllegalArgumentException(e); throw new IllegalArgumentException(e);
} }
macKey.erase(); macKey.erase();
maxPayloadLength = MAX_FRAME_LENGTH - 4 - mac.getMacLength(); maxPayloadLength =
header = new byte[4]; MAX_FRAME_LENGTH - FRAME_HEADER_LENGTH - mac.getMacLength();
header = new byte[FRAME_HEADER_LENGTH];
payload = new byte[maxPayloadLength]; payload = new byte[maxPayloadLength];
footer = new byte[mac.getMacLength()]; footer = new byte[mac.getMacLength()];
} }
@@ -81,7 +82,6 @@ implements ConnectionReader {
assert betweenFrames; assert betweenFrames;
// Don't allow more than 2^32 frames to be read // Don't allow more than 2^32 frames to be read
if(frame > MAX_32_BIT_UNSIGNED) throw new IllegalStateException(); if(frame > MAX_32_BIT_UNSIGNED) throw new IllegalStateException();
frame++;
// Read the header // Read the header
int offset = 0; int offset = 0;
while(offset < header.length) { while(offset < header.length) {
@@ -91,13 +91,12 @@ implements ConnectionReader {
} }
if(offset == 0) return false; // EOF between frames if(offset == 0) return false; // EOF between frames
if(offset < header.length) throw new EOFException(); // Unexpected EOF if(offset < header.length) throw new EOFException(); // Unexpected EOF
mac.update(header); // Check that the frame number is correct and the length is legal
// Check that the payload and padding lengths are legal if(!HeaderEncoder.validateHeader(header, frame, maxPayloadLength))
payloadLen = ByteUtils.readUint16(header, 0);
int paddingLen = ByteUtils.readUint16(header, 2);
if(payloadLen + paddingLen == 0) throw new FormatException();
if(payloadLen + paddingLen > maxPayloadLength)
throw new FormatException(); throw new FormatException();
payloadLen = HeaderEncoder.getPayloadLength(header);
int paddingLen = HeaderEncoder.getPaddingLength(header);
mac.update(header);
// Read the payload // Read the payload
offset = 0; offset = 0;
while(offset < payloadLen) { while(offset < payloadLen) {
@@ -124,6 +123,7 @@ implements ConnectionReader {
decrypter.readMac(footer); decrypter.readMac(footer);
if(!Arrays.equals(expectedMac, footer)) throw new FormatException(); if(!Arrays.equals(expectedMac, footer)) throw new FormatException();
betweenFrames = false; betweenFrames = false;
frame++;
return true; return true;
} }
} }

View File

@@ -1,5 +1,6 @@
package net.sf.briar.transport; package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH; import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED; import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
@@ -10,14 +11,15 @@ import java.io.OutputStream;
import java.security.InvalidKeyException; import java.security.InvalidKeyException;
import javax.crypto.Mac; import javax.crypto.Mac;
import net.sf.briar.api.crypto.ErasableKey;
import net.sf.briar.api.crypto.ErasableKey;
import net.sf.briar.api.transport.ConnectionWriter; import net.sf.briar.api.transport.ConnectionWriter;
import net.sf.briar.util.ByteUtils;
/** /**
* A ConnectionWriter that buffers its input and writes a frame whenever there * A ConnectionWriter that buffers its input and writes a frame whenever there
* is a full-size frame to write or the flush() method is called. * is a full-size frame to write or the flush() method is called.
* <p>
* This class is not thread-safe.
*/ */
class ConnectionWriterImpl extends FilterOutputStream class ConnectionWriterImpl extends FilterOutputStream
implements ConnectionWriter { implements ConnectionWriter {
@@ -42,9 +44,10 @@ implements ConnectionWriter {
throw new IllegalArgumentException(badKey); throw new IllegalArgumentException(badKey);
} }
macKey.erase(); macKey.erase();
maxPayloadLength = MAX_FRAME_LENGTH - 4 - mac.getMacLength(); maxPayloadLength =
MAX_FRAME_LENGTH - FRAME_HEADER_LENGTH - mac.getMacLength();
buf = new ByteArrayOutputStream(maxPayloadLength); buf = new ByteArrayOutputStream(maxPayloadLength);
header = new byte[4]; header = new byte[FRAME_HEADER_LENGTH];
} }
public OutputStream getOutputStream() { public OutputStream getOutputStream() {
@@ -95,7 +98,7 @@ implements ConnectionWriter {
if(frame > MAX_32_BIT_UNSIGNED) throw new IllegalStateException(); if(frame > MAX_32_BIT_UNSIGNED) throw new IllegalStateException();
byte[] payload = buf.toByteArray(); byte[] payload = buf.toByteArray();
if(payload.length > maxPayloadLength) throw new IllegalStateException(); if(payload.length > maxPayloadLength) throw new IllegalStateException();
ByteUtils.writeUint16(payload.length, header, 0); HeaderEncoder.encodeHeader(header, frame, payload.length, 0);
out.write(header); out.write(header);
mac.update(header); mac.update(header);
out.write(payload); out.write(payload);

View File

@@ -0,0 +1,45 @@
package net.sf.briar.transport;
import net.sf.briar.api.transport.TransportConstants;
import net.sf.briar.util.ByteUtils;
class HeaderEncoder {
static void encodeHeader(byte[] header, long frame, int payload,
int padding) {
if(header.length < TransportConstants.FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
if(frame < 0 || frame > ByteUtils.MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
if(payload < 0 || payload > ByteUtils.MAX_16_BIT_UNSIGNED)
throw new IllegalArgumentException();
if(padding < 0 || padding > ByteUtils.MAX_16_BIT_UNSIGNED)
throw new IllegalArgumentException();
ByteUtils.writeUint32(frame, header, 0);
ByteUtils.writeUint16(payload, header, 4);
ByteUtils.writeUint16(padding, header, 6);
}
static boolean validateHeader(byte[] header, long frame, int max) {
if(header.length < TransportConstants.FRAME_HEADER_LENGTH)
return false;
if(ByteUtils.readUint32(header, 0) != frame) return false;
int payload = ByteUtils.readUint16(header, 4);
int padding = ByteUtils.readUint16(header, 6);
if(payload + padding == 0) return false;
if(payload + padding > max) return false;
return true;
}
static int getPayloadLength(byte[] header) {
if(header.length < TransportConstants.FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
return ByteUtils.readUint16(header, 4);
}
static int getPaddingLength(byte[] header) {
if(header.length < TransportConstants.FRAME_HEADER_LENGTH)
throw new IllegalArgumentException();
return ByteUtils.readUint16(header, 6);
}
}

View File

@@ -5,7 +5,7 @@ import net.sf.briar.util.ByteUtils;
class IvEncoder { class IvEncoder {
static byte[] encodeIv(long frame, int blockSize) { static byte[] encodeIv(long frame, int blockSize) {
if(frame > ByteUtils.MAX_32_BIT_UNSIGNED) if(frame < 0 || frame > ByteUtils.MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException(); throw new IllegalArgumentException();
byte[] iv = new byte[blockSize]; byte[] iv = new byte[blockSize];
updateIv(iv, frame); updateIv(iv, frame);

View File

@@ -12,7 +12,7 @@ import net.sf.briar.util.ByteUtils;
class TagEncoder { class TagEncoder {
static byte[] encodeTag(long frame, Cipher tagCipher, ErasableKey tagKey) { static byte[] encodeTag(long frame, Cipher tagCipher, ErasableKey tagKey) {
if(frame > ByteUtils.MAX_32_BIT_UNSIGNED) if(frame < 0 || frame > ByteUtils.MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException(); throw new IllegalArgumentException();
// The plaintext is blank // The plaintext is blank
byte[] plaintext = new byte[TransportConstants.TAG_LENGTH]; byte[] plaintext = new byte[TransportConstants.TAG_LENGTH];
@@ -32,6 +32,8 @@ class TagEncoder {
static boolean validateTag(byte[] tag, long frame, Cipher tagCipher, static boolean validateTag(byte[] tag, long frame, Cipher tagCipher,
ErasableKey tagKey) { ErasableKey tagKey) {
if(frame < 0 || frame > ByteUtils.MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
if(tag.length != TransportConstants.TAG_LENGTH) return false; if(tag.length != TransportConstants.TAG_LENGTH) return false;
// Encode the frame number as a uint32 at the end of the IV // Encode the frame number as a uint32 at the end of the IV
byte[] iv = new byte[tagCipher.getBlockSize()]; byte[] iv = new byte[tagCipher.getBlockSize()];

View File

@@ -1,5 +1,6 @@
package net.sf.briar.transport; package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH; import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static org.junit.Assert.assertArrayEquals; import static org.junit.Assert.assertArrayEquals;
@@ -21,12 +22,13 @@ public class ConnectionReaderImplTest extends TransportTest {
@Test @Test
public void testLengthZero() throws Exception { public void testLengthZero() throws Exception {
int payloadLength = 0; int payloadLength = 0;
byte[] frame = new byte[headerLength + payloadLength + macLength]; byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
writeHeader(frame, payloadLength, 0); + macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
// Calculate the MAC // Calculate the MAC
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + payloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + payloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Read the frame // Read the frame
ByteArrayInputStream in = new ByteArrayInputStream(frame); ByteArrayInputStream in = new ByteArrayInputStream(frame);
ConnectionDecrypter d = new NullConnectionDecrypter(in); ConnectionDecrypter d = new NullConnectionDecrypter(in);
@@ -40,12 +42,13 @@ public class ConnectionReaderImplTest extends TransportTest {
@Test @Test
public void testLengthOne() throws Exception { public void testLengthOne() throws Exception {
int payloadLength = 1; int payloadLength = 1;
byte[] frame = new byte[headerLength + payloadLength + macLength]; byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
writeHeader(frame, payloadLength, 0); + macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
// Calculate the MAC // Calculate the MAC
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + payloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + payloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Read the frame // Read the frame
ByteArrayInputStream in = new ByteArrayInputStream(frame); ByteArrayInputStream in = new ByteArrayInputStream(frame);
ConnectionDecrypter d = new NullConnectionDecrypter(in); ConnectionDecrypter d = new NullConnectionDecrypter(in);
@@ -59,15 +62,15 @@ public class ConnectionReaderImplTest extends TransportTest {
public void testMaxLength() throws Exception { public void testMaxLength() throws Exception {
// First frame: max payload length // First frame: max payload length
byte[] frame = new byte[MAX_FRAME_LENGTH]; byte[] frame = new byte[MAX_FRAME_LENGTH];
writeHeader(frame, maxPayloadLength, 0); HeaderEncoder.encodeHeader(frame, 0, maxPayloadLength, 0);
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + maxPayloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + maxPayloadLength);
mac.doFinal(frame, headerLength + maxPayloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + maxPayloadLength);
// Second frame: max payload length plus one // Second frame: max payload length plus one
byte[] frame1 = new byte[MAX_FRAME_LENGTH + 1]; byte[] frame1 = new byte[MAX_FRAME_LENGTH + 1];
writeHeader(frame1, maxPayloadLength + 1, 0); HeaderEncoder.encodeHeader(frame1, 1, maxPayloadLength + 1, 0);
mac.update(frame1, 0, headerLength + maxPayloadLength + 1); mac.update(frame1, 0, FRAME_HEADER_LENGTH + maxPayloadLength + 1);
mac.doFinal(frame1, headerLength + maxPayloadLength + 1); mac.doFinal(frame1, FRAME_HEADER_LENGTH + maxPayloadLength + 1);
// Concatenate the frames // Concatenate the frames
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write(frame); out.write(frame);
@@ -91,16 +94,17 @@ public class ConnectionReaderImplTest extends TransportTest {
int paddingLength = 10; int paddingLength = 10;
// First frame: max payload length, including padding // First frame: max payload length, including padding
byte[] frame = new byte[MAX_FRAME_LENGTH]; byte[] frame = new byte[MAX_FRAME_LENGTH];
writeHeader(frame, maxPayloadLength - paddingLength, paddingLength); HeaderEncoder.encodeHeader(frame, 0, maxPayloadLength - paddingLength,
paddingLength);
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + maxPayloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + maxPayloadLength);
mac.doFinal(frame, headerLength + maxPayloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + maxPayloadLength);
// Second frame: max payload length plus one, including padding // Second frame: max payload length plus one, including padding
byte[] frame1 = new byte[MAX_FRAME_LENGTH + 1]; byte[] frame1 = new byte[MAX_FRAME_LENGTH + 1];
writeHeader(frame1, maxPayloadLength + 1 - paddingLength, HeaderEncoder.encodeHeader(frame1, 1,
paddingLength); maxPayloadLength + 1 - paddingLength, paddingLength);
mac.update(frame1, 0, headerLength + maxPayloadLength + 1); mac.update(frame1, 0, FRAME_HEADER_LENGTH + maxPayloadLength + 1);
mac.doFinal(frame1, headerLength + maxPayloadLength + 1); mac.doFinal(frame1, FRAME_HEADER_LENGTH + maxPayloadLength + 1);
// Concatenate the frames // Concatenate the frames
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write(frame); out.write(frame);
@@ -122,16 +126,20 @@ public class ConnectionReaderImplTest extends TransportTest {
@Test @Test
public void testMultipleFrames() throws Exception { public void testMultipleFrames() throws Exception {
// First frame: 123-byte payload // First frame: 123-byte payload
byte[] frame = new byte[headerLength + 123 + mac.getMacLength()]; int payloadLength = 123;
writeHeader(frame, 123, 0); byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
+ macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + 123); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + 123); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Second frame: 1234-byte payload // Second frame: 1234-byte payload
byte[] frame1 = new byte[headerLength + 1234 + mac.getMacLength()]; int payloadLength1 = 1234;
writeHeader(frame1, 1234, 0); byte[] frame1 = new byte[FRAME_HEADER_LENGTH + payloadLength1
mac.update(frame1, 0, headerLength + 1234); + macLength];
mac.doFinal(frame1, headerLength + 1234); HeaderEncoder.encodeHeader(frame1, 1, payloadLength1, 0);
mac.update(frame1, 0, FRAME_HEADER_LENGTH + payloadLength1);
mac.doFinal(frame1, FRAME_HEADER_LENGTH + payloadLength1);
// Concatenate the frames // Concatenate the frames
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write(frame); out.write(frame);
@@ -140,23 +148,24 @@ public class ConnectionReaderImplTest extends TransportTest {
ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray()); ByteArrayInputStream in = new ByteArrayInputStream(out.toByteArray());
ConnectionDecrypter d = new NullConnectionDecrypter(in); ConnectionDecrypter d = new NullConnectionDecrypter(in);
ConnectionReader r = new ConnectionReaderImpl(d, mac, macKey); ConnectionReader r = new ConnectionReaderImpl(d, mac, macKey);
byte[] read = new byte[123]; byte[] read = new byte[payloadLength];
TestUtils.readFully(r.getInputStream(), read); TestUtils.readFully(r.getInputStream(), read);
assertArrayEquals(new byte[123], read); assertArrayEquals(new byte[payloadLength], read);
byte[] read1 = new byte[1234]; byte[] read1 = new byte[payloadLength1];
TestUtils.readFully(r.getInputStream(), read1); TestUtils.readFully(r.getInputStream(), read1);
assertArrayEquals(new byte[1234], read1); assertArrayEquals(new byte[payloadLength1], read1);
} }
@Test @Test
public void testCorruptPayload() throws Exception { public void testCorruptPayload() throws Exception {
int payloadLength = 8; int payloadLength = 8;
byte[] frame = new byte[headerLength + payloadLength + macLength]; byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
writeHeader(frame, payloadLength, 0); + macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
// Calculate the MAC // Calculate the MAC
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + payloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + payloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Modify the payload // Modify the payload
frame[12] ^= 1; frame[12] ^= 1;
// Try to read the frame - not a single byte should be read // Try to read the frame - not a single byte should be read
@@ -172,12 +181,13 @@ public class ConnectionReaderImplTest extends TransportTest {
@Test @Test
public void testCorruptMac() throws Exception { public void testCorruptMac() throws Exception {
int payloadLength = 8; int payloadLength = 8;
byte[] frame = new byte[headerLength + payloadLength + macLength]; byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
writeHeader(frame, payloadLength, 0); + macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
// Calculate the MAC // Calculate the MAC
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + payloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + payloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Modify the MAC // Modify the MAC
frame[17] ^= 1; frame[17] ^= 1;
// Try to read the frame - not a single byte should be read // Try to read the frame - not a single byte should be read

View File

@@ -1,5 +1,6 @@
package net.sf.briar.transport; package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH; import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import static org.junit.Assert.assertArrayEquals; import static org.junit.Assert.assertArrayEquals;
@@ -30,12 +31,13 @@ public class ConnectionWriterImplTest extends TransportTest {
@Test @Test
public void testSingleByteFrame() throws Exception { public void testSingleByteFrame() throws Exception {
int payloadLength = 1; int payloadLength = 1;
byte[] frame = new byte[headerLength + payloadLength + macLength]; byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
writeHeader(frame, payloadLength, 0); + macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
// Calculate the MAC // Calculate the MAC
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + payloadLength); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + payloadLength); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Check that the ConnectionWriter gets the same results // Check that the ConnectionWriter gets the same results
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
ConnectionEncrypter e = new NullConnectionEncrypter(out); ConnectionEncrypter e = new NullConnectionEncrypter(out);
@@ -76,16 +78,20 @@ public class ConnectionWriterImplTest extends TransportTest {
@Test @Test
public void testMultipleFrames() throws Exception { public void testMultipleFrames() throws Exception {
// First frame: 123-byte payload // First frame: 123-byte payload
byte[] frame = new byte[headerLength + 123 + macLength]; int payloadLength = 123;
writeHeader(frame, 123, 0); byte[] frame = new byte[FRAME_HEADER_LENGTH + payloadLength
+ macLength];
HeaderEncoder.encodeHeader(frame, 0, payloadLength, 0);
mac.init(macKey); mac.init(macKey);
mac.update(frame, 0, headerLength + 123); mac.update(frame, 0, FRAME_HEADER_LENGTH + payloadLength);
mac.doFinal(frame, headerLength + 123); mac.doFinal(frame, FRAME_HEADER_LENGTH + payloadLength);
// Second frame: 1234-byte payload // Second frame: 1234-byte payload
byte[] frame1 = new byte[headerLength + 1234 + macLength]; int payloadLength1 = 1234;
writeHeader(frame1, 1234, 0); byte[] frame1 = new byte[FRAME_HEADER_LENGTH + payloadLength1
mac.update(frame1, 0, headerLength + 1234); + macLength];
mac.doFinal(frame1, headerLength + 1234); HeaderEncoder.encodeHeader(frame1, 1, payloadLength1, 0);
mac.update(frame1, 0, FRAME_HEADER_LENGTH + 1234);
mac.doFinal(frame1, FRAME_HEADER_LENGTH + 1234);
// Concatenate the frames // Concatenate the frames
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
out.write(frame); out.write(frame);

View File

@@ -1,14 +1,14 @@
package net.sf.briar.transport; package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.FRAME_HEADER_LENGTH;
import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH; import static net.sf.briar.api.transport.TransportConstants.MAX_FRAME_LENGTH;
import javax.crypto.Mac; import javax.crypto.Mac;
import net.sf.briar.api.crypto.ErasableKey;
import junit.framework.TestCase; import junit.framework.TestCase;
import net.sf.briar.api.crypto.CryptoComponent; import net.sf.briar.api.crypto.CryptoComponent;
import net.sf.briar.api.crypto.ErasableKey;
import net.sf.briar.crypto.CryptoModule; import net.sf.briar.crypto.CryptoModule;
import net.sf.briar.util.ByteUtils;
import com.google.inject.Guice; import com.google.inject.Guice;
import com.google.inject.Injector; import com.google.inject.Injector;
@@ -17,7 +17,7 @@ public abstract class TransportTest extends TestCase {
protected final Mac mac; protected final Mac mac;
protected final ErasableKey macKey; protected final ErasableKey macKey;
protected final int headerLength = 4, macLength, maxPayloadLength; protected final int macLength, maxPayloadLength;
public TransportTest() throws Exception { public TransportTest() throws Exception {
super(); super();
@@ -26,11 +26,6 @@ public abstract class TransportTest extends TestCase {
mac = crypto.getMac(); mac = crypto.getMac();
macKey = crypto.generateTestKey(); macKey = crypto.generateTestKey();
macLength = mac.getMacLength(); macLength = mac.getMacLength();
maxPayloadLength = MAX_FRAME_LENGTH - headerLength - macLength; maxPayloadLength = MAX_FRAME_LENGTH - FRAME_HEADER_LENGTH - macLength;
}
static void writeHeader(byte[] b, int payload, int padding) {
ByteUtils.writeUint16(payload, b, 0);
ByteUtils.writeUint16(padding, b, 2);
} }
} }