Make sure senderkeys encrypt is correctly initialized.

libaxolotl/src/androidTest/java/org/whispersystems/test/groups/GroupCipherTest.java

@@ -6,6 +6,7 @@ import android.util.Log;
 import org.whispersystems.libaxolotl.DuplicateMessageException;
 import org.whispersystems.libaxolotl.InvalidMessageException;
 import org.whispersystems.libaxolotl.LegacyMessageException;
+import org.whispersystems.libaxolotl.NoSessionException;
 import org.whispersystems.libaxolotl.ecc.ECKeyPair;
 import org.whispersystems.libaxolotl.groups.GroupCipher;
 import org.whispersystems.libaxolotl.groups.GroupSessionBuilder;
@@ -21,7 +22,7 @@ import java.util.List;
 public class GroupCipherTest extends AndroidTestCase {
 
   public void testBasicEncryptDecrypt()
-      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException
+      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException, NoSessionException
   {
     InMemorySenderKeyStore aliceStore = new InMemorySenderKeyStore();
     InMemorySenderKeyStore bobStore   = new InMemorySenderKeyStore();
@@ -49,7 +50,7 @@ public class GroupCipherTest extends AndroidTestCase {
   }
 
   public void testBasicRatchet()
-      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException
+      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException, NoSessionException
   {
     InMemorySenderKeyStore aliceStore = new InMemorySenderKeyStore();
     InMemorySenderKeyStore bobStore   = new InMemorySenderKeyStore();
@@ -92,7 +93,7 @@ public class GroupCipherTest extends AndroidTestCase {
   }
 
   public void testOutOfOrder()
-      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException
+      throws LegacyMessageException, DuplicateMessageException, InvalidMessageException, NoSessionException
   {
     InMemorySenderKeyStore aliceStore = new InMemorySenderKeyStore();
     InMemorySenderKeyStore bobStore   = new InMemorySenderKeyStore();
@@ -129,6 +130,17 @@ public class GroupCipherTest extends AndroidTestCase {
     }
   }
 
+  public void testEncryptNoSession() {
+    InMemorySenderKeyStore aliceStore = new InMemorySenderKeyStore();
+    GroupCipher aliceGroupCipher = new GroupCipher(aliceStore, "groupWithBobInIt");
+    try {
+      aliceGroupCipher.encrypt("up the punks".getBytes());
+      throw new AssertionError("Should have failed!");
+    } catch (NoSessionException nse) {
+      // good
+    }
+  }
+
   private int randomInt() {
     try {
       return SecureRandom.getInstance("SHA1PRNG").nextInt(Integer.MAX_VALUE);

libaxolotl/src/main/java/org/whispersystems/libaxolotl/NoSessionException.java

@@ -4,4 +4,8 @@ public class NoSessionException extends Exception {
   public NoSessionException(String s) {
     super(s);
   }
+
+  public NoSessionException(Exception nested) {
+    super(nested);
+  }
 }

libaxolotl/src/main/java/org/whispersystems/libaxolotl/groups/GroupCipher.java

@@ -1,18 +1,16 @@
 package org.whispersystems.libaxolotl.groups;
 
-import android.util.Log;
-
 import org.whispersystems.libaxolotl.DuplicateMessageException;
 import org.whispersystems.libaxolotl.InvalidKeyIdException;
 import org.whispersystems.libaxolotl.InvalidMessageException;
 import org.whispersystems.libaxolotl.LegacyMessageException;
+import org.whispersystems.libaxolotl.NoSessionException;
 import org.whispersystems.libaxolotl.groups.ratchet.SenderChainKey;
 import org.whispersystems.libaxolotl.groups.ratchet.SenderMessageKey;
 import org.whispersystems.libaxolotl.groups.state.SenderKeyRecord;
 import org.whispersystems.libaxolotl.groups.state.SenderKeyState;
-import org.whispersystems.libaxolotl.protocol.SenderKeyMessage;
 import org.whispersystems.libaxolotl.groups.state.SenderKeyStore;
-
+import org.whispersystems.libaxolotl.protocol.SenderKeyMessage;
 
 import java.security.InvalidAlgorithmParameterException;
 import java.security.NoSuchAlgorithmException;
@@ -36,23 +34,27 @@ public class GroupCipher {
     this.senderKeyId    = senderKeyId;
   }
 
-  public byte[] encrypt(byte[] paddedPlaintext) {
+  public byte[] encrypt(byte[] paddedPlaintext) throws NoSessionException {
     synchronized (LOCK) {
-      SenderKeyRecord  record         = senderKeyStore.loadSenderKey(senderKeyId);
+      try {
-      SenderKeyState   senderKeyState = record.getSenderKeyState();
+        SenderKeyRecord  record         = senderKeyStore.loadSenderKey(senderKeyId);
-      SenderMessageKey senderKey      = senderKeyState.getSenderChainKey().getSenderMessageKey();
+        SenderKeyState   senderKeyState = record.getSenderKeyState();
-      byte[]           ciphertext     = getCipherText(senderKey.getIv(), senderKey.getCipherKey(), paddedPlaintext);
+        SenderMessageKey senderKey      = senderKeyState.getSenderChainKey().getSenderMessageKey();
+        byte[]           ciphertext     = getCipherText(senderKey.getIv(), senderKey.getCipherKey(), paddedPlaintext);
 
-      SenderKeyMessage senderKeyMessage = new SenderKeyMessage(senderKeyState.getKeyId(),
+        SenderKeyMessage senderKeyMessage = new SenderKeyMessage(senderKeyState.getKeyId(),
-                                                               senderKey.getIteration(),
+                                                                 senderKey.getIteration(),
-                                                               ciphertext,
+                                                                 ciphertext,
-                                                               senderKeyState.getSigningKeyPrivate());
+                                                                 senderKeyState.getSigningKeyPrivate());
 
-      senderKeyState.setSenderChainKey(senderKeyState.getSenderChainKey().getNext());
+        senderKeyState.setSenderChainKey(senderKeyState.getSenderChainKey().getNext());
 
-      senderKeyStore.storeSenderKey(senderKeyId, record);
+        senderKeyStore.storeSenderKey(senderKeyId, record);
 
-      return senderKeyMessage.serialize();
+        return senderKeyMessage.serialize();
+      } catch (InvalidKeyIdException e) {
+        throw new NoSessionException(e);
+      }
     }
   }
 

libaxolotl/src/main/java/org/whispersystems/libaxolotl/groups/state/SenderKeyRecord.java

@@ -3,7 +3,6 @@ package org.whispersystems.libaxolotl.groups.state;
 import org.whispersystems.libaxolotl.InvalidKeyIdException;
 import org.whispersystems.libaxolotl.ecc.ECKeyPair;
 import org.whispersystems.libaxolotl.ecc.ECPublicKey;
-import org.whispersystems.libaxolotl.groups.state.SenderKeyState;
 import org.whispersystems.libaxolotl.state.StorageProtos;
 
 import java.io.IOException;
@@ -26,8 +25,12 @@ public class SenderKeyRecord {
     }
   }
 
-  public SenderKeyState getSenderKeyState() {
+  public SenderKeyState getSenderKeyState() throws InvalidKeyIdException {
-    return senderKeyStates.get(0);
+    if (!senderKeyStates.isEmpty()) {
+      return senderKeyStates.get(0);
+    } else {
+      throw new InvalidKeyIdException("No key state in record!");
+    }
   }
 
   public SenderKeyState getSenderKeyState(int keyId) throws InvalidKeyIdException {

libaxolotl/src/main/java/org/whispersystems/libaxolotl/groups/state/SenderKeyState.java

@@ -1,7 +1,5 @@
 package org.whispersystems.libaxolotl.groups.state;
 
-import android.util.Log;
-
 import com.google.protobuf.ByteString;
 
 import org.whispersystems.libaxolotl.InvalidKeyException;

libaxolotl/src/main/java/org/whispersystems/libaxolotl/groups/state/SenderKeyStore.java

@@ -1,7 +1,5 @@
 package org.whispersystems.libaxolotl.groups.state;
 
-import org.whispersystems.libaxolotl.groups.state.SenderKeyRecord;
-
 public interface SenderKeyStore {
   public void storeSenderKey(String senderKeyId, SenderKeyRecord record);
   public SenderKeyRecord loadSenderKey(String senderKeyId);