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Derive and store secrets when a contact transport is added.

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This commit is contained in:
akwizgran
2012-10-24 23:34:46 +01:00
parent 79a8d1c19d
commit 1b8478df84
4 changed files with 88 additions and 38 deletions
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12
api/net/sf/briar/api/crypto/KeyManager.java
View File

@@ -1,15 +1,15 @@
package net.sf.briar.api.crypto;
import net.sf.briar.api.ContactId;
import net.sf.briar.api.db.ContactTransport;
import net.sf.briar.api.protocol.TransportId;
import net.sf.briar.api.transport.ConnectionContext;
public interface KeyManager {
/**
* Starts the key manager and returns true if the manager started
* successfully. This method must be called after the database has been
* opened.
* Starts the key manager and returns true if it started successfully. This
* method must be called after the database has been opened.
*/
boolean start();
@@ -22,4 +22,10 @@ public interface KeyManager {
* support the transport.
*/
ConnectionContext getConnectionContext(ContactId c, TransportId t);
/**
* Called whenever a contact transport has been added. The initial secret
* is erased before returning.
*/
void contactTransportAdded(ContactTransport ct, byte[] initialSecret);
}

8
api/net/sf/briar/api/db/TemporarySecret.java
View File

@@ -30,10 +30,10 @@ public class TemporarySecret extends ContactTransport {
secret, 0L, 0L, new byte[CONNECTION_WINDOW_SIZE / 8]);
}
/** Creates a temporary secret derived from the given temporary secret. */
public TemporarySecret(TemporarySecret old, long period, byte[] secret) {
this(old.getContactId(), old.getTransportId(), old.getEpoch(),
old.getClockDifference(), old.getLatency(), old.getAlice(),
/** Creates a temporary secret derived from the given contact transport. */
public TemporarySecret(ContactTransport ct, long period, byte[] secret) {
this(ct.getContactId(), ct.getTransportId(), ct.getEpoch(),
ct.getClockDifference(), ct.getLatency(), ct.getAlice(),
period, secret);
}

65
components/net/sf/briar/transport/KeyManagerImpl.java
View File

@@ -1,6 +1,7 @@
package net.sf.briar.transport;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
@@ -13,6 +14,7 @@ import java.util.logging.Logger;
import net.sf.briar.api.ContactId;
import net.sf.briar.api.crypto.CryptoComponent;
import net.sf.briar.api.crypto.KeyManager;
import net.sf.briar.api.db.ContactTransport;
import net.sf.briar.api.db.DatabaseComponent;
import net.sf.briar.api.db.DbException;
import net.sf.briar.api.db.TemporarySecret;
@@ -26,8 +28,6 @@ import net.sf.briar.util.ByteUtils;
import com.google.inject.Inject;
// FIXME: When a contact transport is added we need to load its secrets
class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
private static final int MS_BETWEEN_CHECKS = 60 * 1000;
@@ -94,9 +94,7 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
Collection<TemporarySecret> secrets) {
Collection<TemporarySecret> dead = new ArrayList<TemporarySecret>();
for(TemporarySecret s : secrets) {
ContactId c = s.getContactId();
TransportId t = s.getTransportId();
ContactTransportKey k = new ContactTransportKey(c, t);
ContactTransportKey k = new ContactTransportKey(s);
long rotationPeriod = getRotationPeriod(s);
long creationTime = getCreationTime(s);
long activationTime = creationTime + s.getClockDifference();
@@ -128,9 +126,7 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
Collection<TemporarySecret> dead) {
Collection<TemporarySecret> created = new ArrayList<TemporarySecret>();
for(TemporarySecret s : dead) {
ContactId c = s.getContactId();
TransportId t = s.getTransportId();
ContactTransportKey k = new ContactTransportKey(c, t);
ContactTransportKey k = new ContactTransportKey(s);
if(incomingNew.containsKey(k)) throw new IllegalStateException();
byte[] secret = s.getSecret();
long period = s.getPeriod();
@@ -153,8 +149,8 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
// Derive the two current incoming secrets
byte[] secret1, secret2;
secret1 = secret;
for(long l = period; l < currentPeriod; l++) {
byte[] temp = crypto.deriveNextSecret(secret1, l);
for(long p = period; p < currentPeriod; p++) {
byte[] temp = crypto.deriveNextSecret(secret1, p);
ByteUtils.erase(secret1);
secret1 = temp;
}
@@ -181,7 +177,7 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
return created;
}
private long getRotationPeriod(TemporarySecret s) {
private long getRotationPeriod(ContactTransport s) {
return 2 * s.getClockDifference() + s.getLatency();
}
@@ -219,6 +215,49 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
return new ConnectionContext(c, t, secret, connection, s.getAlice());
}
public synchronized void contactTransportAdded(ContactTransport ct,
byte[] initialSecret) {
long now = System.currentTimeMillis();
long rotationPeriod = getRotationPeriod(ct);
long elapsed = now - ct.getEpoch();
long currentPeriod = elapsed / rotationPeriod;
if(currentPeriod < 1) throw new IllegalArgumentException();
// Derive the two current incoming secrets
byte[] secret1, secret2;
secret1 = initialSecret;
for(long p = 0; p < currentPeriod; p++) {
byte[] temp = crypto.deriveNextSecret(secret1, p);
ByteUtils.erase(secret1);
secret1 = temp;
}
secret2 = crypto.deriveNextSecret(secret1, currentPeriod);
// One of the incoming secrets is the current outgoing secret
ContactTransportKey k = new ContactTransportKey(ct);
TemporarySecret s1, s2;
s1 = new TemporarySecret(ct, currentPeriod - 1, secret1);
incomingOld.put(k, s1);
s2 = new TemporarySecret(ct, currentPeriod, secret2);
incomingNew.put(k, s2);
if(elapsed % rotationPeriod < ct.getClockDifference()) {
// The outgoing secret is the newer incoming secret
outgoing.put(k, s2);
} else {
// The outgoing secret is the older incoming secret
outgoing.put(k, s1);
}
// Store the new secrets
try {
db.addSecrets(Arrays.asList(s1, s2));
} catch(DbException e) {
if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.toString());
}
// Pass the new secrets to the recogniser
recogniser.addSecret(s1);
recogniser.addSecret(s2);
// Erase the initial secret
ByteUtils.erase(initialSecret);
}
@Override
public synchronized void run() {
// Rebuild the maps because we may be running a whole period late
@@ -287,6 +326,10 @@ class KeyManagerImpl extends TimerTask implements KeyManager, DatabaseListener {
this.transportId = transportId;
}
private ContactTransportKey(ContactTransport ct) {
this(ct.getContactId(), ct.getTransportId());
}
@Override
public int hashCode() {
return contactId.hashCode() + transportId.hashCode();

41
test/net/sf/briar/protocol/simplex/SimplexProtocolIntegrationTest.java
View File

@@ -14,8 +14,8 @@ import net.sf.briar.TestDatabaseModule;
import net.sf.briar.TestUtils;
import net.sf.briar.api.ContactId;
import net.sf.briar.api.crypto.KeyManager;
import net.sf.briar.api.db.ContactTransport;
import net.sf.briar.api.db.DatabaseComponent;
import net.sf.briar.api.db.TemporarySecret;
import net.sf.briar.api.db.event.DatabaseEvent;
import net.sf.briar.api.db.event.DatabaseListener;
import net.sf.briar.api.db.event.MessagesAddedEvent;
@@ -57,7 +57,7 @@ public class SimplexProtocolIntegrationTest extends BriarTestCase {
private final File aliceDir = new File(testDir, "alice");
private final File bobDir = new File(testDir, "bob");
private final TransportId transportId;
private final byte[] secret;
private final byte[] initialSecret;
private final long epoch;
private Injector alice, bob;
@@ -66,8 +66,8 @@ public class SimplexProtocolIntegrationTest extends BriarTestCase {
super();
transportId = new TransportId(TestUtils.getRandomId());
// Create matching secrets for Alice and Bob
secret = new byte[32];
new Random().nextBytes(secret);
initialSecret = new byte[32];
new Random().nextBytes(initialSecret);
long rotationPeriod = 2 * CLOCK_DIFFERENCE + LATENCY;
epoch = System.currentTimeMillis() - 2 * rotationPeriod;
}
@@ -103,15 +103,15 @@ public class SimplexProtocolIntegrationTest extends BriarTestCase {
// Open Alice's database
DatabaseComponent db = alice.getInstance(DatabaseComponent.class);
db.open(false);
// Add Bob as a contact
ContactId contactId = db.addContact();
TemporarySecret s = new TemporarySecret(contactId, transportId, epoch,
CLOCK_DIFFERENCE, LATENCY, true, 0L, secret);
db.addContactTransport(s);
db.addSecrets(Collections.singletonList(s));
// Start Alice's key manager
KeyManager km = alice.getInstance(KeyManager.class);
km.start();
// Add Bob as a contact
ContactId contactId = db.addContact();
ContactTransport ct = new ContactTransport(contactId, transportId,
epoch, CLOCK_DIFFERENCE, LATENCY, true);
db.addContactTransport(ct);
km.contactTransportAdded(ct, initialSecret.clone());
// Send Bob a message
String subject = "Hello";
byte[] body = "Hi Bob!".getBytes("UTF-8");
@@ -147,18 +147,18 @@ public class SimplexProtocolIntegrationTest extends BriarTestCase {
// Open Bob's database
DatabaseComponent db = bob.getInstance(DatabaseComponent.class);
db.open(false);
// Set up a database listener
MessageListener listener = new MessageListener();
db.addListener(listener);
// Add Alice as a contact
ContactId contactId = db.addContact();
TemporarySecret s = new TemporarySecret(contactId, transportId, epoch,
CLOCK_DIFFERENCE, LATENCY, false, 0L, secret);
db.addContactTransport(s);
db.addSecrets(Collections.singletonList(s));
// Start Bob's key manager
KeyManager km = bob.getInstance(KeyManager.class);
km.start();
// Add Alice as a contact
ContactId contactId = db.addContact();
ContactTransport ct = new ContactTransport(contactId, transportId,
epoch, CLOCK_DIFFERENCE, LATENCY, false);
db.addContactTransport(ct);
km.contactTransportAdded(ct, initialSecret.clone());
// Set up a database listener
MessageListener listener = new MessageListener();
db.addListener(listener);
// Fake a transport update from Alice
TransportUpdate transportUpdate = new TransportUpdate() {
@@ -216,7 +216,8 @@ public class SimplexProtocolIntegrationTest extends BriarTestCase {
private boolean messagesAdded = false;
public void eventOccurred(DatabaseEvent e) {
if(e instanceof MessagesAddedEvent) messagesAdded = true;
if(e instanceof MessagesAddedEvent)
messagesAdded = true;
}
}
}