From 68b4760dfadd645f649ddf5dff1edd9b04ce5e46 Mon Sep 17 00:00:00 2001
From: akwizgran <akwizgran@users.sourceforge.net>
Date: Fri, 12 Aug 2011 14:26:56 +0200
Subject: [PATCH] Use a constant for the tag size.
---
.../sf/briar/api/transport/PacketReader.java | 4 +--
.../net/sf/briar/crypto/SharedSecret.java | 2 +-
.../transport/ConnectionRecogniserImpl.java | 3 ++-
.../net/sf/briar/transport/Constants.java | 2 +-
.../sf/briar/transport/PacketEncrypter.java | 3 +++
.../briar/transport/PacketEncrypterImpl.java | 7 +++--
.../net/sf/briar/transport/TagEncoder.java | 2 +-
.../net/sf/briar/crypto/SharedSecretTest.java | 12 ++++-----
.../ConnectionRecogniserImplTest.java | 2 +-
.../transport/PacketEncrypterImplTest.java | 13 +++++-----
.../briar/transport/PacketWriterImplTest.java | 26 ++++++++++++-------
11 files changed, 43 insertions(+), 33 deletions(-)
diff --git a/api/net/sf/briar/api/transport/PacketReader.java b/api/net/sf/briar/api/transport/PacketReader.java
index 7094bb025f..0dde50d327 100644
--- a/api/net/sf/briar/api/transport/PacketReader.java
+++ b/api/net/sf/briar/api/transport/PacketReader.java
@@ -10,8 +10,8 @@ import net.sf.briar.api.protocol.SubscriptionUpdate;
import net.sf.briar.api.protocol.TransportUpdate;
/**
- * Reads unencrypted packets from an underlying input stream and authenticates
- * them.
+ * Reads encrypted packets from an underlying input stream, decrypts and
+ * authenticates them.
*/
public interface PacketReader {
diff --git a/components/net/sf/briar/crypto/SharedSecret.java b/components/net/sf/briar/crypto/SharedSecret.java
index 5c144dcc56..2240164517 100644
--- a/components/net/sf/briar/crypto/SharedSecret.java
+++ b/components/net/sf/briar/crypto/SharedSecret.java
@@ -16,7 +16,7 @@ import javax.crypto.spec.IvParameterSpec;
*/
class SharedSecret {
- private static final int IV_BYTES = 16;
+ static final int IV_BYTES = 16;
private final IvParameterSpec iv;
private final boolean alice;
diff --git a/components/net/sf/briar/transport/ConnectionRecogniserImpl.java b/components/net/sf/briar/transport/ConnectionRecogniserImpl.java
index 6779c6ad72..605a0ffbe1 100644
--- a/components/net/sf/briar/transport/ConnectionRecogniserImpl.java
+++ b/components/net/sf/briar/transport/ConnectionRecogniserImpl.java
@@ -92,7 +92,8 @@ DatabaseListener {
public synchronized ContactId acceptConnection(byte[] tag)
throws DbException {
- if(tag.length != 16) throw new IllegalArgumentException();
+ if(tag.length != Constants.TAG_BYTES)
+ throw new IllegalArgumentException();
if(!initialised) initialise();
Bytes b = new Bytes(tag);
ContactId contactId = tagToContact.remove(b);
diff --git a/components/net/sf/briar/transport/Constants.java b/components/net/sf/briar/transport/Constants.java
index 07c96eaa06..07d8a1fd23 100644
--- a/components/net/sf/briar/transport/Constants.java
+++ b/components/net/sf/briar/transport/Constants.java
@@ -2,7 +2,7 @@ package net.sf.briar.transport;
interface Constants {
+ static final int TAG_BYTES = 16;
static final int MAX_16_BIT_UNSIGNED = 65535; // 2^16 - 1
static final long MAX_32_BIT_UNSIGNED = 4294967295L; // 2^32 - 1
-
}
diff --git a/components/net/sf/briar/transport/PacketEncrypter.java b/components/net/sf/briar/transport/PacketEncrypter.java
index 17543dacee..7652753b26 100644
--- a/components/net/sf/briar/transport/PacketEncrypter.java
+++ b/components/net/sf/briar/transport/PacketEncrypter.java
@@ -5,9 +5,12 @@ import java.io.OutputStream;
interface PacketEncrypter {
+ /** Returns the output stream to which packets should be written. */
OutputStream getOutputStream();
+ /** Encrypts the given tag and writes it to the underlying output stream. */
void writeTag(byte[] tag) throws IOException;
+ /** Finishes writing the current packet. */
void finishPacket() throws IOException;
}
diff --git a/components/net/sf/briar/transport/PacketEncrypterImpl.java b/components/net/sf/briar/transport/PacketEncrypterImpl.java
index ebde477130..69ca0c9ca3 100644
--- a/components/net/sf/briar/transport/PacketEncrypterImpl.java
+++ b/components/net/sf/briar/transport/PacketEncrypterImpl.java
@@ -15,14 +15,12 @@ import javax.crypto.spec.IvParameterSpec;
class PacketEncrypterImpl extends FilterOutputStream
implements PacketEncrypter {
- private final OutputStream out;
private final Cipher tagCipher, packetCipher;
private final SecretKey packetKey;
PacketEncrypterImpl(OutputStream out, Cipher tagCipher,
Cipher packetCipher, SecretKey tagKey, SecretKey packetKey) {
super(out);
- this.out = out;
this.tagCipher = tagCipher;
this.packetCipher = packetCipher;
this.packetKey = packetKey;
@@ -31,7 +29,7 @@ implements PacketEncrypter {
} catch(InvalidKeyException e) {
throw new IllegalArgumentException(e);
}
- if(tagCipher.getOutputSize(16) != 16)
+ if(tagCipher.getOutputSize(Constants.TAG_BYTES) != Constants.TAG_BYTES)
throw new IllegalArgumentException();
}
@@ -40,7 +38,8 @@ implements PacketEncrypter {
}
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);
try {
out.write(tagCipher.doFinal(tag));
diff --git a/components/net/sf/briar/transport/TagEncoder.java b/components/net/sf/briar/transport/TagEncoder.java
index aead6debbf..98c0b1fe87 100644
--- a/components/net/sf/briar/transport/TagEncoder.java
+++ b/components/net/sf/briar/transport/TagEncoder.java
@@ -4,7 +4,7 @@ public class TagEncoder {
static byte[] encodeTag(int transportIdentifier, long connectionNumber,
long packetNumber) {
- byte[] tag = new byte[16];
+ byte[] tag = new byte[Constants.TAG_BYTES];
// Encode the transport identifier as an unsigned 16-bit integer
writeUint16(transportIdentifier, tag, 2);
// Encode the connection number as an unsigned 32-bit integer
diff --git a/test/net/sf/briar/crypto/SharedSecretTest.java b/test/net/sf/briar/crypto/SharedSecretTest.java
index ebaa879976..7de0c80b35 100644
--- a/test/net/sf/briar/crypto/SharedSecretTest.java
+++ b/test/net/sf/briar/crypto/SharedSecretTest.java
@@ -14,22 +14,22 @@ public class SharedSecretTest extends TestCase {
Random random = new Random();
byte[] secret = new byte[40];
random.nextBytes(secret);
- secret[16] = (byte) 0;
+ secret[SharedSecret.IV_BYTES] = (byte) 0;
SharedSecret s = new SharedSecret(secret);
assertTrue(Arrays.equals(secret, s.getBytes()));
- secret[16] = (byte) 1;
+ secret[SharedSecret.IV_BYTES] = (byte) 1;
s = new SharedSecret(secret);
assertTrue(Arrays.equals(secret, s.getBytes()));
// The Alice flag must be either 0 or 1
- secret[16] = (byte) 2;
+ secret[SharedSecret.IV_BYTES] = (byte) 2;
try {
s = new SharedSecret(secret);
fail();
} catch(IllegalArgumentException expected) {}
- // The secret must be at least 18 bytes long
- secret = new byte[17];
+ // The ciphertext must be at least 1 byte long
+ secret = new byte[SharedSecret.IV_BYTES + 1];
random.nextBytes(secret);
- secret[16] = (byte) 0;
+ secret[SharedSecret.IV_BYTES] = (byte) 0;
try {
s = new SharedSecret(secret);
fail();
diff --git a/test/net/sf/briar/transport/ConnectionRecogniserImplTest.java b/test/net/sf/briar/transport/ConnectionRecogniserImplTest.java
index 7ec47deb53..948a7872ae 100644
--- a/test/net/sf/briar/transport/ConnectionRecogniserImplTest.java
+++ b/test/net/sf/briar/transport/ConnectionRecogniserImplTest.java
@@ -53,7 +53,7 @@ public class ConnectionRecogniserImplTest extends TestCase {
}});
final ConnectionRecogniserImpl c =
new ConnectionRecogniserImpl(transportId, crypto, db);
- assertNull(c.acceptConnection(new byte[16]));
+ assertNull(c.acceptConnection(new byte[Constants.TAG_BYTES]));
context.assertIsSatisfied();
}
diff --git a/test/net/sf/briar/transport/PacketEncrypterImplTest.java b/test/net/sf/briar/transport/PacketEncrypterImplTest.java
index 8cd64954eb..2132223f2c 100644
--- a/test/net/sf/briar/transport/PacketEncrypterImplTest.java
+++ b/test/net/sf/briar/transport/PacketEncrypterImplTest.java
@@ -36,7 +36,7 @@ public class PacketEncrypterImplTest extends TestCase {
ByteArrayOutputStream out = new ByteArrayOutputStream();
PacketEncrypter p = new PacketEncrypterImpl(out, tagCipher,
packetCipher, tagKey, packetKey);
- p.writeTag(new byte[16]);
+ p.writeTag(new byte[Constants.TAG_BYTES]);
p.getOutputStream().write((byte) 0);
p.finishPacket();
assertEquals(17, out.toByteArray().length);
@@ -44,7 +44,7 @@ public class PacketEncrypterImplTest extends TestCase {
@Test
public void testEncryption() throws Exception {
- byte[] tag = new byte[16];
+ byte[] tag = new byte[Constants.TAG_BYTES];
byte[] packet = new byte[123];
// Calculate the expected encrypted tag
tagCipher.init(Cipher.ENCRYPT_MODE, tagKey);
@@ -63,14 +63,15 @@ public class PacketEncrypterImplTest extends TestCase {
p.getOutputStream().write(packet);
p.finishPacket();
byte[] ciphertext = out.toByteArray();
- assertEquals(16 + packet.length, ciphertext.length);
+ assertEquals(Constants.TAG_BYTES + packet.length, ciphertext.length);
// Check the tag
- byte[] actualTag = new byte[16];
- System.arraycopy(ciphertext, 0, actualTag, 0, 16);
+ byte[] actualTag = new byte[Constants.TAG_BYTES];
+ System.arraycopy(ciphertext, 0, actualTag, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag, actualTag));
// Check the packet
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));
}
}
diff --git a/test/net/sf/briar/transport/PacketWriterImplTest.java b/test/net/sf/briar/transport/PacketWriterImplTest.java
index 94783c7a28..c79234b364 100644
--- a/test/net/sf/briar/transport/PacketWriterImplTest.java
+++ b/test/net/sf/briar/transport/PacketWriterImplTest.java
@@ -36,8 +36,9 @@ public class PacketWriterImplTest extends TestCase {
PacketEncrypter e = new NullPacketEncrypter(out);
PacketWriter p = new PacketWriterImpl(e, mac, 0, 0L);
p.getOutputStream().write(0);
- // There should be 16 zero bytes for the tag, 1 for the byte written
- assertTrue(Arrays.equals(new byte[17], out.toByteArray()));
+ // There should be TAG_BYTES bytes for the tag, 1 byte for the write
+ assertTrue(Arrays.equals(new byte[Constants.TAG_BYTES + 1],
+ out.toByteArray()));
}
@Test
@@ -93,6 +94,7 @@ public class PacketWriterImplTest extends TestCase {
+ "00000000" // 32 bits for the packet number
+ "00000000" // 32 bits for the block number
);
+ assertEquals(Constants.TAG_BYTES, expectedTag.length);
byte[] expectedTag1 = StringUtils.fromHexString(
"0000" // 16 bits reserved
+ "F00D" // 16 bits for the transport ID
@@ -100,6 +102,7 @@ public class PacketWriterImplTest extends TestCase {
+ "00000001" // 32 bits for the packet number
+ "00000000" // 32 bits for the block number
);
+ assertEquals(Constants.TAG_BYTES, expectedTag1.length);
// Calculate what the MAC on the first packet should be
mac.update(expectedTag);
mac.update((byte) 0);
@@ -119,24 +122,27 @@ public class PacketWriterImplTest extends TestCase {
p.getOutputStream().write(0);
p.nextPacket();
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);
// Check the first packet's tag
- byte[] actualTag = new byte[16];
- System.arraycopy(written, 0, actualTag, 0, 16);
+ byte[] actualTag = new byte[Constants.TAG_BYTES];
+ System.arraycopy(written, 0, actualTag, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag, actualTag));
// Check the first packet's MAC
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));
// Check the second packet's tag
- byte[] actualTag1 = new byte[16];
- System.arraycopy(written, 17 + expectedMac.length, actualTag1, 0, 16);
+ byte[] actualTag1 = new byte[Constants.TAG_BYTES];
+ System.arraycopy(written, Constants.TAG_BYTES + 1 + expectedMac.length,
+ actualTag1, 0, Constants.TAG_BYTES);
assertTrue(Arrays.equals(expectedTag1, actualTag1));
// Check the second packet's MAC
byte[] actualMac1 = new byte[expectedMac1.length];
- System.arraycopy(written, 17 + expectedMac.length + 17, actualMac1, 0,
- actualMac1.length);
+ System.arraycopy(written, Constants.TAG_BYTES + 1 + expectedMac.length
+ + Constants.TAG_BYTES + 1, actualMac1, 0, actualMac1.length);
assertTrue(Arrays.equals(expectedMac1, actualMac1));
}
--
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