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Code Issues Projects Releases Wiki Activity

Use a constant for the tag size.

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This commit is contained in:
akwizgran
2011-08-12 14:26:56 +02:00
parent f0cf825ca9
commit 68b4760dfa
11 changed files with 43 additions and 33 deletions
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4
api/net/sf/briar/api/transport/PacketReader.java
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@@ -10,8 +10,8 @@ import net.sf.briar.api.protocol.SubscriptionUpdate;
import net.sf.briar.api.protocol.TransportUpdate; import net.sf.briar.api.protocol.TransportUpdate;
/** /**
* Reads unencrypted packets from an underlying input stream and authenticates * Reads encrypted packets from an underlying input stream, decrypts and
* them. * authenticates them.
*/ */
public interface PacketReader { public interface PacketReader {

2
components/net/sf/briar/crypto/SharedSecret.java
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@@ -16,7 +16,7 @@ import javax.crypto.spec.IvParameterSpec;
*/ */
class SharedSecret { class SharedSecret {
private static final int IV_BYTES = 16; static final int IV_BYTES = 16;
private final IvParameterSpec iv; private final IvParameterSpec iv;
private final boolean alice; private final boolean alice;

3
components/net/sf/briar/transport/ConnectionRecogniserImpl.java
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@@ -92,7 +92,8 @@ DatabaseListener {
public synchronized ContactId acceptConnection(byte[] tag) public synchronized ContactId acceptConnection(byte[] tag)
throws DbException { throws DbException {
if(tag.length != 16) throw new IllegalArgumentException(); if(tag.length != Constants.TAG_BYTES)
throw new IllegalArgumentException();
if(!initialised) initialise(); if(!initialised) initialise();
Bytes b = new Bytes(tag); Bytes b = new Bytes(tag);
ContactId contactId = tagToContact.remove(b); ContactId contactId = tagToContact.remove(b);

2
components/net/sf/briar/transport/Constants.java
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@@ -2,7 +2,7 @@ package net.sf.briar.transport;
interface Constants { interface Constants {
static final int TAG_BYTES = 16;
static final int MAX_16_BIT_UNSIGNED = 65535; // 2^16 - 1 static final int MAX_16_BIT_UNSIGNED = 65535; // 2^16 - 1
static final long MAX_32_BIT_UNSIGNED = 4294967295L; // 2^32 - 1 static final long MAX_32_BIT_UNSIGNED = 4294967295L; // 2^32 - 1
} }

3
components/net/sf/briar/transport/PacketEncrypter.java
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@@ -5,9 +5,12 @@ import java.io.OutputStream;
interface PacketEncrypter { interface PacketEncrypter {
/** Returns the output stream to which packets should be written. */
OutputStream getOutputStream(); OutputStream getOutputStream();
/** Encrypts the given tag and writes it to the underlying output stream. */
void writeTag(byte[] tag) throws IOException; void writeTag(byte[] tag) throws IOException;
/** Finishes writing the current packet. */
void finishPacket() throws IOException; void finishPacket() throws IOException;
} }

7
components/net/sf/briar/transport/PacketEncrypterImpl.java
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@@ -15,14 +15,12 @@ import javax.crypto.spec.IvParameterSpec;
class PacketEncrypterImpl extends FilterOutputStream class PacketEncrypterImpl extends FilterOutputStream
implements PacketEncrypter { implements PacketEncrypter {
private final OutputStream out;
private final Cipher tagCipher, packetCipher; private final Cipher tagCipher, packetCipher;
private final SecretKey packetKey; private final SecretKey packetKey;
PacketEncrypterImpl(OutputStream out, Cipher tagCipher, PacketEncrypterImpl(OutputStream out, Cipher tagCipher,
Cipher packetCipher, SecretKey tagKey, SecretKey packetKey) { Cipher packetCipher, SecretKey tagKey, SecretKey packetKey) {
super(out); super(out);
this.out = out;
this.tagCipher = tagCipher; this.tagCipher = tagCipher;
this.packetCipher = packetCipher; this.packetCipher = packetCipher;
this.packetKey = packetKey; this.packetKey = packetKey;
@@ -31,7 +29,7 @@ implements PacketEncrypter {
} catch(InvalidKeyException e) { } catch(InvalidKeyException e) {
throw new IllegalArgumentException(e); throw new IllegalArgumentException(e);
} }
if(tagCipher.getOutputSize(16) != 16) if(tagCipher.getOutputSize(Constants.TAG_BYTES) != Constants.TAG_BYTES)
throw new IllegalArgumentException(); throw new IllegalArgumentException();
} }
@@ -40,7 +38,8 @@ implements PacketEncrypter {
} }
public void writeTag(byte[] tag) throws IOException { public void writeTag(byte[] tag) throws IOException {
if(tag.length != 16) throw new IllegalArgumentException(); if(tag.length != Constants.TAG_BYTES)
throw new IllegalArgumentException();
IvParameterSpec iv = new IvParameterSpec(tag); IvParameterSpec iv = new IvParameterSpec(tag);
try { try {
out.write(tagCipher.doFinal(tag)); out.write(tagCipher.doFinal(tag));

2
components/net/sf/briar/transport/TagEncoder.java
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@@ -4,7 +4,7 @@ public class TagEncoder {
static byte[] encodeTag(int transportIdentifier, long connectionNumber, static byte[] encodeTag(int transportIdentifier, long connectionNumber,
long packetNumber) { long packetNumber) {
byte[] tag = new byte[16]; byte[] tag = new byte[Constants.TAG_BYTES];
// Encode the transport identifier as an unsigned 16-bit integer // Encode the transport identifier as an unsigned 16-bit integer
writeUint16(transportIdentifier, tag, 2); writeUint16(transportIdentifier, tag, 2);
// Encode the connection number as an unsigned 32-bit integer // Encode the connection number as an unsigned 32-bit integer

12
test/net/sf/briar/crypto/SharedSecretTest.java
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@@ -14,22 +14,22 @@ public class SharedSecretTest extends TestCase {
Random random = new Random(); Random random = new Random();
byte[] secret = new byte[40]; byte[] secret = new byte[40];
random.nextBytes(secret); random.nextBytes(secret);
secret[16] = (byte) 0; secret[SharedSecret.IV_BYTES] = (byte) 0;
SharedSecret s = new SharedSecret(secret); SharedSecret s = new SharedSecret(secret);
assertTrue(Arrays.equals(secret, s.getBytes())); assertTrue(Arrays.equals(secret, s.getBytes()));
secret[16] = (byte) 1; secret[SharedSecret.IV_BYTES] = (byte) 1;
s = new SharedSecret(secret); s = new SharedSecret(secret);
assertTrue(Arrays.equals(secret, s.getBytes())); assertTrue(Arrays.equals(secret, s.getBytes()));
// The Alice flag must be either 0 or 1 // The Alice flag must be either 0 or 1
secret[16] = (byte) 2; secret[SharedSecret.IV_BYTES] = (byte) 2;
try { try {
s = new SharedSecret(secret); s = new SharedSecret(secret);
fail(); fail();
} catch(IllegalArgumentException expected) {} } catch(IllegalArgumentException expected) {}
// The secret must be at least 18 bytes long // The ciphertext must be at least 1 byte long
secret = new byte[17]; secret = new byte[SharedSecret.IV_BYTES + 1];
random.nextBytes(secret); random.nextBytes(secret);
secret[16] = (byte) 0; secret[SharedSecret.IV_BYTES] = (byte) 0;
try { try {
s = new SharedSecret(secret); s = new SharedSecret(secret);
fail(); fail();

2
test/net/sf/briar/transport/ConnectionRecogniserImplTest.java
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@@ -53,7 +53,7 @@ public class ConnectionRecogniserImplTest extends TestCase {
}}); }});
final ConnectionRecogniserImpl c = final ConnectionRecogniserImpl c =
new ConnectionRecogniserImpl(transportId, crypto, db); new ConnectionRecogniserImpl(transportId, crypto, db);
assertNull(c.acceptConnection(new byte[16])); assertNull(c.acceptConnection(new byte[Constants.TAG_BYTES]));
context.assertIsSatisfied(); context.assertIsSatisfied();
} }

13
test/net/sf/briar/transport/PacketEncrypterImplTest.java
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@@ -36,7 +36,7 @@ public class PacketEncrypterImplTest extends TestCase {
ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayOutputStream out = new ByteArrayOutputStream();
PacketEncrypter p = new PacketEncrypterImpl(out, tagCipher, PacketEncrypter p = new PacketEncrypterImpl(out, tagCipher,
packetCipher, tagKey, packetKey); packetCipher, tagKey, packetKey);
p.writeTag(new byte[16]); p.writeTag(new byte[Constants.TAG_BYTES]);
p.getOutputStream().write((byte) 0); p.getOutputStream().write((byte) 0);
p.finishPacket(); p.finishPacket();
assertEquals(17, out.toByteArray().length); assertEquals(17, out.toByteArray().length);
@@ -44,7 +44,7 @@ public class PacketEncrypterImplTest extends TestCase {
@Test @Test
public void testEncryption() throws Exception { public void testEncryption() throws Exception {
byte[] tag = new byte[16]; byte[] tag = new byte[Constants.TAG_BYTES];
byte[] packet = new byte[123]; byte[] packet = new byte[123];
// Calculate the expected encrypted tag // Calculate the expected encrypted tag
tagCipher.init(Cipher.ENCRYPT_MODE, tagKey); tagCipher.init(Cipher.ENCRYPT_MODE, tagKey);
@@ -63,14 +63,15 @@ public class PacketEncrypterImplTest extends TestCase {
p.getOutputStream().write(packet); p.getOutputStream().write(packet);
p.finishPacket(); p.finishPacket();
byte[] ciphertext = out.toByteArray(); byte[] ciphertext = out.toByteArray();
assertEquals(16 + packet.length, ciphertext.length); assertEquals(Constants.TAG_BYTES + packet.length, ciphertext.length);
// Check the tag // Check the tag
byte[] actualTag = new byte[16]; byte[] actualTag = new byte[Constants.TAG_BYTES];
System.arraycopy(ciphertext, 0, actualTag, 0, 16); System.arraycopy(ciphertext, 0, actualTag, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag, actualTag)); assertTrue(Arrays.equals(expectedTag, actualTag));
// Check the packet // Check the packet
byte[] actualPacket = new byte[packet.length]; byte[] actualPacket = new byte[packet.length];
System.arraycopy(ciphertext, 16, actualPacket, 0, actualPacket.length); System.arraycopy(ciphertext, Constants.TAG_BYTES, actualPacket, 0,
actualPacket.length);
assertTrue(Arrays.equals(expectedPacket, actualPacket)); assertTrue(Arrays.equals(expectedPacket, actualPacket));
} }
} }

26
test/net/sf/briar/transport/PacketWriterImplTest.java
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@@ -36,8 +36,9 @@ public class PacketWriterImplTest extends TestCase {
PacketEncrypter e = new NullPacketEncrypter(out); PacketEncrypter e = new NullPacketEncrypter(out);
PacketWriter p = new PacketWriterImpl(e, mac, 0, 0L); PacketWriter p = new PacketWriterImpl(e, mac, 0, 0L);
p.getOutputStream().write(0); p.getOutputStream().write(0);
// There should be 16 zero bytes for the tag, 1 for the byte written // There should be TAG_BYTES bytes for the tag, 1 byte for the write
assertTrue(Arrays.equals(new byte[17], out.toByteArray())); assertTrue(Arrays.equals(new byte[Constants.TAG_BYTES + 1],
out.toByteArray()));
} }
@Test @Test
@@ -93,6 +94,7 @@ public class PacketWriterImplTest extends TestCase {
+ "00000000" // 32 bits for the packet number + "00000000" // 32 bits for the packet number
+ "00000000" // 32 bits for the block number + "00000000" // 32 bits for the block number
); );
assertEquals(Constants.TAG_BYTES, expectedTag.length);
byte[] expectedTag1 = StringUtils.fromHexString( byte[] expectedTag1 = StringUtils.fromHexString(
"0000" // 16 bits reserved "0000" // 16 bits reserved
+ "F00D" // 16 bits for the transport ID + "F00D" // 16 bits for the transport ID
@@ -100,6 +102,7 @@ public class PacketWriterImplTest extends TestCase {
+ "00000001" // 32 bits for the packet number + "00000001" // 32 bits for the packet number
+ "00000000" // 32 bits for the block number + "00000000" // 32 bits for the block number
); );
assertEquals(Constants.TAG_BYTES, expectedTag1.length);
// Calculate what the MAC on the first packet should be // Calculate what the MAC on the first packet should be
mac.update(expectedTag); mac.update(expectedTag);
mac.update((byte) 0); mac.update((byte) 0);
@@ -119,24 +122,27 @@ public class PacketWriterImplTest extends TestCase {
p.getOutputStream().write(0); p.getOutputStream().write(0);
p.nextPacket(); p.nextPacket();
byte[] written = out.toByteArray(); byte[] written = out.toByteArray();
assertEquals(17 + expectedMac.length + 17 + expectedMac1.length, assertEquals(Constants.TAG_BYTES + 1 + expectedMac.length
+ Constants.TAG_BYTES + 1 + expectedMac1.length,
written.length); written.length);
// Check the first packet's tag // Check the first packet's tag
byte[] actualTag = new byte[16]; byte[] actualTag = new byte[Constants.TAG_BYTES];
System.arraycopy(written, 0, actualTag, 0, 16); System.arraycopy(written, 0, actualTag, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag, actualTag)); assertTrue(Arrays.equals(expectedTag, actualTag));
// Check the first packet's MAC // Check the first packet's MAC
byte[] actualMac = new byte[expectedMac.length]; byte[] actualMac = new byte[expectedMac.length];
System.arraycopy(written, 17, actualMac, 0, actualMac.length); System.arraycopy(written, Constants.TAG_BYTES + 1, actualMac, 0,
actualMac.length);
assertTrue(Arrays.equals(expectedMac, actualMac)); assertTrue(Arrays.equals(expectedMac, actualMac));
// Check the second packet's tag // Check the second packet's tag
byte[] actualTag1 = new byte[16]; byte[] actualTag1 = new byte[Constants.TAG_BYTES];
System.arraycopy(written, 17 + expectedMac.length, actualTag1, 0, 16); System.arraycopy(written, Constants.TAG_BYTES + 1 + expectedMac.length,
actualTag1, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag1, actualTag1)); assertTrue(Arrays.equals(expectedTag1, actualTag1));
// Check the second packet's MAC // Check the second packet's MAC
byte[] actualMac1 = new byte[expectedMac1.length]; byte[] actualMac1 = new byte[expectedMac1.length];
System.arraycopy(written, 17 + expectedMac.length + 17, actualMac1, 0, System.arraycopy(written, Constants.TAG_BYTES + 1 + expectedMac.length
actualMac1.length); + Constants.TAG_BYTES + 1, actualMac1, 0, actualMac1.length);
assertTrue(Arrays.equals(expectedMac1, actualMac1)); assertTrue(Arrays.equals(expectedMac1, actualMac1));
} }