From 7739bcdd068a40ab7c6e64487871f63645f73fb5 Mon Sep 17 00:00:00 2001
From: akwizgran <michael@briarproject.org>
Date: Mon, 8 Oct 2012 18:15:25 +0100
Subject: [PATCH] Second part of key rotation implementation. Work in progress.
---
.../api/transport/ConnectionRecogniser.java | 10 +-
.../briar/api/transport/ConnectionWindow.java | 12 --
.../transport/ConnectionRecogniserImpl.java | 67 ++++++++
...nWindowImpl.java => ConnectionWindow.java} | 60 ++++---
.../net/sf/briar/transport/TagEncoder.java | 25 +--
.../TransportConnectionRecogniser.java | 160 ++++++++++++++++++
test/build.xml | 2 +-
...mplTest.java => ConnectionWindowTest.java} | 31 +---
8 files changed, 291 insertions(+), 76 deletions(-)
delete mode 100644 api/net/sf/briar/api/transport/ConnectionWindow.java
create mode 100644 components/net/sf/briar/transport/ConnectionRecogniserImpl.java
rename components/net/sf/briar/transport/{ConnectionWindowImpl.java => ConnectionWindow.java} (53%)
create mode 100644 components/net/sf/briar/transport/TransportConnectionRecogniser.java
rename test/net/sf/briar/transport/{ConnectionWindowImplTest.java => ConnectionWindowTest.java} (74%)
diff --git a/api/net/sf/briar/api/transport/ConnectionRecogniser.java b/api/net/sf/briar/api/transport/ConnectionRecogniser.java
index 6bcf2f3bd1..61ca17daff 100644
--- a/api/net/sf/briar/api/transport/ConnectionRecogniser.java
+++ b/api/net/sf/briar/api/transport/ConnectionRecogniser.java
@@ -1,5 +1,6 @@
package net.sf.briar.api.transport;
+import net.sf.briar.api.ContactId;
import net.sf.briar.api.db.DbException;
import net.sf.briar.api.protocol.TransportId;
@@ -14,5 +15,12 @@ public interface ConnectionRecogniser {
* expected, or null if the connection was not expected.
*/
ConnectionContext acceptConnection(TransportId t, byte[] tag)
- throws DbException;
+ throws DbException;
+
+ void addWindow(ContactId c, TransportId t, long period, boolean alice,
+ byte[] secret, long centre, byte[] bitmap) throws DbException;
+
+ void removeWindow(ContactId c, TransportId t, long period);
+
+ void removeWindows(ContactId c);
}
diff --git a/api/net/sf/briar/api/transport/ConnectionWindow.java b/api/net/sf/briar/api/transport/ConnectionWindow.java
deleted file mode 100644
index e2ecd94903..0000000000
--- a/api/net/sf/briar/api/transport/ConnectionWindow.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package net.sf.briar.api.transport;
-
-import java.util.Set;
-
-public interface ConnectionWindow {
-
- boolean isSeen(long connection);
-
- void setSeen(long connection);
-
- Set<Long> getUnseen();
-}
diff --git a/components/net/sf/briar/transport/ConnectionRecogniserImpl.java b/components/net/sf/briar/transport/ConnectionRecogniserImpl.java
new file mode 100644
index 0000000000..3917b0c48f
--- /dev/null
+++ b/components/net/sf/briar/transport/ConnectionRecogniserImpl.java
@@ -0,0 +1,67 @@
+package net.sf.briar.transport;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.protocol.TransportId;
+import net.sf.briar.api.transport.ConnectionContext;
+import net.sf.briar.api.transport.ConnectionRecogniser;
+
+import com.google.inject.Inject;
+
+class ConnectionRecogniserImpl implements ConnectionRecogniser {
+
+ private final CryptoComponent crypto;
+ private final DatabaseComponent db;
+ // Locking: this
+ private final Map<TransportId, TransportConnectionRecogniser> recognisers;
+
+ @Inject
+ ConnectionRecogniserImpl(CryptoComponent crypto, DatabaseComponent db) {
+ this.crypto = crypto;
+ this.db = db;
+ recognisers = new HashMap<TransportId, TransportConnectionRecogniser>();
+ }
+
+ public ConnectionContext acceptConnection(TransportId t, byte[] tag)
+ throws DbException {
+ TransportConnectionRecogniser r;
+ synchronized(this) {
+ r = recognisers.get(t);
+ }
+ if(r == null) return null;
+ return r.acceptConnection(tag);
+ }
+
+ public void addWindow(ContactId c, TransportId t, long period,
+ boolean alice, byte[] secret, long centre, byte[] bitmap)
+ throws DbException {
+ TransportConnectionRecogniser r;
+ synchronized(this) {
+ r = recognisers.get(t);
+ if(r == null) {
+ r = new TransportConnectionRecogniser(crypto, db, t);
+ recognisers.put(t, r);
+ }
+ }
+ r.addWindow(c, period, alice, secret, centre, bitmap);
+ }
+
+ public void removeWindow(ContactId c, TransportId t, long period) {
+ TransportConnectionRecogniser r;
+ synchronized(this) {
+ r = recognisers.get(t);
+ }
+ if(r != null) r.removeWindow(c, period);
+ }
+
+ public synchronized void removeWindows(ContactId c) {
+ for(TransportConnectionRecogniser r : recognisers.values()) {
+ r.removeWindows(c);
+ }
+ }
+}
diff --git a/components/net/sf/briar/transport/ConnectionWindowImpl.java b/components/net/sf/briar/transport/ConnectionWindow.java
similarity index 53%
rename from components/net/sf/briar/transport/ConnectionWindowImpl.java
rename to components/net/sf/briar/transport/ConnectionWindow.java
index 057cd9335a..3a2ced3163 100644
--- a/components/net/sf/briar/transport/ConnectionWindowImpl.java
+++ b/components/net/sf/briar/transport/ConnectionWindow.java
@@ -3,59 +3,75 @@ package net.sf.briar.transport;
import static net.sf.briar.api.transport.TransportConstants.CONNECTION_WINDOW_SIZE;
import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
+import java.util.ArrayList;
+import java.util.Collection;
import java.util.HashSet;
import java.util.Set;
-import net.sf.briar.api.transport.ConnectionWindow;
-
// This class is not thread-safe
-class ConnectionWindowImpl implements ConnectionWindow {
+class ConnectionWindow {
private final Set<Long> unseen;
private long centre;
- ConnectionWindowImpl() {
+ ConnectionWindow() {
unseen = new HashSet<Long>();
for(long l = 0; l < CONNECTION_WINDOW_SIZE / 2; l++) unseen.add(l);
centre = 0;
}
- ConnectionWindowImpl(Set<Long> unseen) {
- long min = Long.MAX_VALUE, max = Long.MIN_VALUE;
- for(long l : unseen) {
- if(l < 0 || l > MAX_32_BIT_UNSIGNED)
- throw new IllegalArgumentException();
- if(l < min) min = l;
- if(l > max) max = l;
- }
- if(max - min > CONNECTION_WINDOW_SIZE)
+ ConnectionWindow(long centre, byte[] bitmap) {
+ if(centre < 0 || centre > MAX_32_BIT_UNSIGNED)
+ throw new IllegalArgumentException();
+ if(bitmap.length != CONNECTION_WINDOW_SIZE / 8)
throw new IllegalArgumentException();
- centre = max - CONNECTION_WINDOW_SIZE / 2 + 1;
- for(long l = centre; l <= max; l++) {
- if(!unseen.contains(l)) throw new IllegalArgumentException();
+ unseen = new HashSet<Long>();
+ long bottom = getBottom(centre);
+ long top = getTop(centre);
+ for(long l = bottom; l < top; l++) {
+ int offset = (int) (l - bottom);
+ int bytes = offset / 8;
+ int bits = offset % 8;
+ if((bitmap[bytes] & (128 >> bits)) == 0) unseen.add(l);
}
- this.unseen = unseen;
+ this.centre = centre;
}
- public boolean isSeen(long connection) {
+ boolean isSeen(long connection) {
return !unseen.contains(connection);
}
- public void setSeen(long connection) {
+ Collection<Long> setSeen(long connection) {
long bottom = getBottom(centre);
long top = getTop(centre);
if(connection < bottom || connection > top)
throw new IllegalArgumentException();
if(!unseen.remove(connection))
throw new IllegalArgumentException();
+ Collection<Long> changed = new ArrayList<Long>();
if(connection >= centre) {
centre = connection + 1;
long newBottom = getBottom(centre);
long newTop = getTop(centre);
- for(long l = bottom; l < newBottom; l++) unseen.remove(l);
- for(long l = top + 1; l <= newTop; l++) unseen.add(l);
+ for(long l = bottom; l < newBottom; l++) {
+ if(unseen.remove(l)) changed.add(l);
+ }
+ for(long l = top + 1; l <= newTop; l++) {
+ if(unseen.add(l)) changed.add(l);
+ }
}
+ return changed;
+ }
+
+ long getCentre() {
+ return centre;
+ }
+
+ byte[] getBitmap() {
+ byte[] bitmap = new byte[CONNECTION_WINDOW_SIZE / 8];
+ // FIXME
+ return bitmap;
}
// Returns the lowest value contained in a window with the given centre
@@ -69,7 +85,7 @@ class ConnectionWindowImpl implements ConnectionWindow {
centre + CONNECTION_WINDOW_SIZE / 2 - 1);
}
- public Set<Long> getUnseen() {
+ public Collection<Long> getUnseen() {
return unseen;
}
}
diff --git a/components/net/sf/briar/transport/TagEncoder.java b/components/net/sf/briar/transport/TagEncoder.java
index 404870e1f5..fc0e1a85fc 100644
--- a/components/net/sf/briar/transport/TagEncoder.java
+++ b/components/net/sf/briar/transport/TagEncoder.java
@@ -1,21 +1,25 @@
package net.sf.briar.transport;
-import static javax.crypto.Cipher.DECRYPT_MODE;
import static javax.crypto.Cipher.ENCRYPT_MODE;
import static net.sf.briar.api.transport.TransportConstants.TAG_LENGTH;
+import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
import java.security.GeneralSecurityException;
import javax.crypto.Cipher;
import net.sf.briar.api.crypto.ErasableKey;
+import net.sf.briar.util.ByteUtils;
class TagEncoder {
- static void encodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey) {
+ static void encodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey,
+ long connection) {
if(tag.length < TAG_LENGTH) throw new IllegalArgumentException();
- // Blank plaintext
+ if(connection < 0 || connection > MAX_32_BIT_UNSIGNED)
+ throw new IllegalArgumentException();
for(int i = 0; i < TAG_LENGTH; i++) tag[i] = 0;
+ ByteUtils.writeUint32(connection, tag, 0);
try {
tagCipher.init(ENCRYPT_MODE, tagKey);
int encrypted = tagCipher.doFinal(tag, 0, TAG_LENGTH, tag);
@@ -25,19 +29,4 @@ class TagEncoder {
throw new IllegalArgumentException(e);
}
}
-
- static boolean decodeTag(byte[] tag, Cipher tagCipher, ErasableKey tagKey) {
- if(tag.length < TAG_LENGTH) throw new IllegalArgumentException();
- try {
- tagCipher.init(DECRYPT_MODE, tagKey);
- int decrypted = tagCipher.doFinal(tag, 0, TAG_LENGTH, tag);
- if(decrypted != TAG_LENGTH) throw new IllegalArgumentException();
- //The plaintext should be blank
- for(int i = 0; i < TAG_LENGTH; i++) if(tag[i] != 0) return false;
- return true;
- } catch(GeneralSecurityException e) {
- // Unsuitable cipher or key
- throw new IllegalArgumentException(e);
- }
- }
}
diff --git a/components/net/sf/briar/transport/TransportConnectionRecogniser.java b/components/net/sf/briar/transport/TransportConnectionRecogniser.java
new file mode 100644
index 0000000000..9ddaacfc28
--- /dev/null
+++ b/components/net/sf/briar/transport/TransportConnectionRecogniser.java
@@ -0,0 +1,160 @@
+package net.sf.briar.transport;
+
+import static net.sf.briar.api.transport.TransportConstants.TAG_LENGTH;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.crypto.Cipher;
+
+import net.sf.briar.api.Bytes;
+import net.sf.briar.api.ContactId;
+import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.ErasableKey;
+import net.sf.briar.api.db.DatabaseComponent;
+import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.protocol.TransportId;
+import net.sf.briar.api.transport.ConnectionContext;
+import net.sf.briar.util.ByteUtils;
+
+/** A connection recogniser for a specific transport. */
+class TransportConnectionRecogniser {
+
+ private final CryptoComponent crypto;
+ private final DatabaseComponent db;
+ private final TransportId transportId;
+ private final Map<Bytes, WindowContext> tagMap; // Locking: this
+ private final Map<RemovalKey, RemovalContext> windowMap; // Locking: this
+
+ TransportConnectionRecogniser(CryptoComponent crypto, DatabaseComponent db,
+ TransportId transportId) {
+ this.crypto = crypto;
+ this.db = db;
+ this.transportId = transportId;
+ tagMap = new HashMap<Bytes, WindowContext>();
+ windowMap = new HashMap<RemovalKey, RemovalContext>();
+ }
+
+ synchronized ConnectionContext acceptConnection(byte[] tag)
+ throws DbException {
+ WindowContext wctx = tagMap.remove(new Bytes(tag));
+ if(wctx == null) return null;
+ ConnectionWindow w = wctx.window;
+ ConnectionContext ctx = wctx.context;
+ long connection = ctx.getConnectionNumber();
+ Cipher cipher = crypto.getTagCipher();
+ ErasableKey key = crypto.deriveTagKey(ctx.getSecret(), ctx.getAlice());
+ byte[] changedTag = new byte[TAG_LENGTH];
+ Bytes changedTagWrapper = new Bytes(changedTag);
+ for(long conn : w.setSeen(connection)) {
+ TagEncoder.encodeTag(changedTag, cipher, key, conn);
+ WindowContext old;
+ if(conn <= connection) old = tagMap.remove(changedTagWrapper);
+ else old = tagMap.put(changedTagWrapper, wctx);
+ assert old == null;
+ }
+ key.erase();
+ ContactId c = ctx.getContactId();
+ long centre = w.getCentre();
+ byte[] bitmap = w.getBitmap();
+ db.setConnectionWindow(c, transportId, wctx.period, centre, bitmap);
+ return wctx.context;
+ }
+
+ synchronized void addWindow(ContactId c, long period, boolean alice,
+ byte[] secret, long centre, byte[] bitmap) throws DbException {
+ Cipher cipher = crypto.getTagCipher();
+ ErasableKey key = crypto.deriveTagKey(secret, alice);
+ ConnectionWindow w = new ConnectionWindow(centre, bitmap);
+ for(long conn : w.getUnseen()) {
+ byte[] tag = new byte[TAG_LENGTH];
+ TagEncoder.encodeTag(tag, cipher, key, conn);
+ ConnectionContext ctx = new ConnectionContext(c, transportId, tag,
+ secret, conn, alice);
+ WindowContext wctx = new WindowContext(w, ctx, period);
+ tagMap.put(new Bytes(tag), wctx);
+ }
+ db.setConnectionWindow(c, transportId, period, centre, bitmap);
+ RemovalContext ctx = new RemovalContext(w, secret, alice);
+ windowMap.put(new RemovalKey(c, period), ctx);
+ }
+
+ synchronized void removeWindow(ContactId c, long period) {
+ RemovalContext ctx = windowMap.remove(new RemovalKey(c, period));
+ if(ctx == null) throw new IllegalArgumentException();
+ Cipher cipher = crypto.getTagCipher();
+ ErasableKey key = crypto.deriveTagKey(ctx.secret, ctx.alice);
+ byte[] removedTag = new byte[TAG_LENGTH];
+ Bytes removedTagWrapper = new Bytes(removedTag);
+ for(long conn : ctx.window.getUnseen()) {
+ TagEncoder.encodeTag(removedTag, cipher, key, conn);
+ WindowContext old = tagMap.remove(removedTagWrapper);
+ assert old != null;
+ }
+ key.erase();
+ ByteUtils.erase(ctx.secret);
+ }
+
+ synchronized void removeWindows(ContactId c) {
+ Collection<RemovalKey> keysToRemove = new ArrayList<RemovalKey>();
+ for(RemovalKey k : windowMap.keySet()) {
+ if(k.contactId.equals(c)) keysToRemove.add(k);
+ }
+ for(RemovalKey k : keysToRemove) removeWindow(k.contactId, k.period);
+ }
+
+ private static class WindowContext {
+
+ private final ConnectionWindow window;
+ private final ConnectionContext context;
+ private final long period;
+
+ private WindowContext(ConnectionWindow window,
+ ConnectionContext context, long period) {
+ this.window = window;
+ this.context = context;
+ this.period = period;
+ }
+ }
+
+ private static class RemovalKey {
+
+ private final ContactId contactId;
+ private final long period;
+
+ private RemovalKey(ContactId contactId, long period) {
+ this.contactId = contactId;
+ this.period = period;
+ }
+
+ @Override
+ public int hashCode() {
+ return contactId.hashCode()+ (int) period;
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if(o instanceof RemovalKey) {
+ RemovalKey w = (RemovalKey) o;
+ return contactId.equals(w.contactId) && period == w.period;
+ }
+ return false;
+ }
+ }
+
+ private static class RemovalContext {
+
+ private final ConnectionWindow window;
+ private final byte[] secret;
+ private final boolean alice;
+
+ private RemovalContext(ConnectionWindow window, byte[] secret,
+ boolean alice) {
+ this.window = window;
+ this.secret = secret;
+ this.alice = alice;
+ }
+ }
+}
diff --git a/test/build.xml b/test/build.xml
index 3b86a959e8..a83fab2ee6 100644
--- a/test/build.xml
+++ b/test/build.xml
@@ -49,7 +49,7 @@
<test name='net.sf.briar.serial.WriterImplTest'/>
<test name='net.sf.briar.transport.ConnectionReaderImplTest'/>
<test name='net.sf.briar.transport.ConnectionRegistryImplTest'/>
- <test name='net.sf.briar.transport.ConnectionWindowImplTest'/>
+ <test name='net.sf.briar.transport.ConnectionWindowTest'/>
<test name='net.sf.briar.transport.ConnectionWriterImplTest'/>
<test name='net.sf.briar.transport.IncomingEncryptionLayerTest'/>
<test name='net.sf.briar.transport.OutgoingEncryptionLayerTest'/>
diff --git a/test/net/sf/briar/transport/ConnectionWindowImplTest.java b/test/net/sf/briar/transport/ConnectionWindowTest.java
similarity index 74%
rename from test/net/sf/briar/transport/ConnectionWindowImplTest.java
rename to test/net/sf/briar/transport/ConnectionWindowTest.java
index 0db1d33684..74de234cf9 100644
--- a/test/net/sf/briar/transport/ConnectionWindowImplTest.java
+++ b/test/net/sf/briar/transport/ConnectionWindowTest.java
@@ -1,20 +1,16 @@
package net.sf.briar.transport;
-import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
-
-import java.util.HashSet;
-import java.util.Set;
+import java.util.Collection;
import net.sf.briar.BriarTestCase;
-import net.sf.briar.api.transport.ConnectionWindow;
import org.junit.Test;
-public class ConnectionWindowImplTest extends BriarTestCase {
+public class ConnectionWindowTest extends BriarTestCase {
@Test
public void testWindowSliding() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
for(int i = 0; i < 100; i++) {
assertFalse(w.isSeen(i));
w.setSeen(i);
@@ -24,7 +20,7 @@ public class ConnectionWindowImplTest extends BriarTestCase {
@Test
public void testWindowJumping() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
for(int i = 0; i < 100; i += 13) {
assertFalse(w.isSeen(i));
w.setSeen(i);
@@ -34,7 +30,7 @@ public class ConnectionWindowImplTest extends BriarTestCase {
@Test
public void testWindowUpperLimit() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
// Centre is 0, highest value in window is 15
w.setSeen(15);
// Centre is 16, highest value in window is 31
@@ -44,20 +40,11 @@ public class ConnectionWindowImplTest extends BriarTestCase {
w.setSeen(48);
fail();
} catch(IllegalArgumentException expected) {}
- // Values greater than 2^32 - 1 should never be allowed
- Set<Long> unseen = new HashSet<Long>();
- for(int i = 0; i < 32; i++) unseen.add(MAX_32_BIT_UNSIGNED - i);
- w = new ConnectionWindowImpl(unseen);
- w.setSeen(MAX_32_BIT_UNSIGNED);
- try {
- w.setSeen(MAX_32_BIT_UNSIGNED + 1);
- fail();
- } catch(IllegalArgumentException expected) {}
}
@Test
public void testWindowLowerLimit() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
// Centre is 0, negative values should never be allowed
try {
w.setSeen(-1);
@@ -87,7 +74,7 @@ public class ConnectionWindowImplTest extends BriarTestCase {
@Test
public void testCannotSetSeenTwice() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
w.setSeen(15);
try {
w.setSeen(15);
@@ -97,9 +84,9 @@ public class ConnectionWindowImplTest extends BriarTestCase {
@Test
public void testGetUnseenConnectionNumbers() {
- ConnectionWindow w = new ConnectionWindowImpl();
+ ConnectionWindow w = new ConnectionWindow();
// Centre is 0; window should cover 0 to 15, inclusive, with none seen
- Set<Long> unseen = w.getUnseen();
+ Collection<Long> unseen = w.getUnseen();
assertEquals(16, unseen.size());
for(int i = 0; i < 16; i++) {
assertTrue(unseen.contains(Long.valueOf(i)));
--
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