Clean up integrity checking code. Try every available slot, not just the first one.

app/src/main/java/me/impy/aegis/AuthActivity.java

@@ -19,9 +19,14 @@ import android.widget.LinearLayout;
 import android.widget.TextView;
 
 import java.lang.reflect.UndeclaredThrowableException;
-import java.util.Arrays;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.security.spec.InvalidKeySpecException;
 
+import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
 import javax.crypto.SecretKey;
 
 import me.impy.aegis.crypto.CryptoUtils;
@@ -31,6 +36,7 @@ import me.impy.aegis.crypto.slots.FingerprintSlot;
 import me.impy.aegis.crypto.slots.PasswordSlot;
 import me.impy.aegis.crypto.slots.Slot;
 import me.impy.aegis.crypto.slots.SlotCollection;
+import me.impy.aegis.crypto.slots.SlotIntegrityException;
 import me.impy.aegis.finger.FingerprintUiHelper;
 import me.impy.aegis.helpers.AuthHelper;
 
@@ -84,43 +90,70 @@ public class AuthActivity extends AppCompatActivity implements FingerprintUiHelp
         button.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
-                MasterKey masterKey = null;
+                trySlots(PasswordSlot.class);
-                try {
-                    if (slots.has(PasswordSlot.class)) {
-                        PasswordSlot slot = slots.find(PasswordSlot.class);
-                        char[] password = AuthHelper.getPassword(textPassword, true);
-                        SecretKey key = slot.deriveKey(password);
-                        CryptoUtils.zero(password);
-                        Cipher cipher = Slot.createCipher(key, Cipher.DECRYPT_MODE);
-                        masterKey = MasterKey.decryptSlot(slot, cipher);
-                    } else {
-                        throw new RuntimeException();
-                    }
-                } catch (Exception e) {
-                    // TODO: feedback
-                    throw new UndeclaredThrowableException(e);
-                }
-
-                setKey(masterKey);
             }
         });
     }
 
-    private void setKey(MasterKey key) {
+    private void showError() {
-        if (!Arrays.equals(slots.getMasterHash(), key.getHash())) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(this);
-            AlertDialog.Builder builder = new AlertDialog.Builder(this);
+        builder.setMessage("Master key integrity check failed for every slot. Make sure you didn't mistype your password.");
-            builder.setMessage("Unable to decrypt the master key with the given key.");
+        builder.setCancelable(false);
-            builder.setCancelable(false);
+        builder.setPositiveButton("OK",
-            builder.setPositiveButton("OK",
                 new DialogInterface.OnClickListener() {
                     public void onClick(DialogInterface dialog, int id) {
                         dialog.cancel();
                     }
                 });
-            builder.create().show();
+        builder.create().show();
-            return;
+    }
-        }
 
+    private MasterKey decryptPasswordSlot(PasswordSlot slot) throws Exception {
+        char[] password = AuthHelper.getPassword(textPassword, true);
+        SecretKey key = slot.deriveKey(password);
+        CryptoUtils.zero(password);
+        Cipher cipher = Slot.createCipher(key, Cipher.DECRYPT_MODE);
+        return slots.decrypt(slot, cipher);
+    }
+
+    private MasterKey decryptFingerSlot(FingerprintSlot slot) throws Exception {
+        return slots.decrypt(slot, fingerCipher);
+    }
+
+    private <T extends Slot> void trySlots(Class<T> type) {
+        try {
+            if (!slots.has(type)) {
+                throw new RuntimeException();
+            }
+
+            MasterKey masterKey = null;
+            for (Slot slot : slots.findAll(type)) {
+                try {
+                    if (slot instanceof PasswordSlot) {
+                        masterKey = decryptPasswordSlot((PasswordSlot) slot);
+                    } else if (slot instanceof FingerprintSlot) {
+                        masterKey = decryptFingerSlot((FingerprintSlot) slot);
+                    } else {
+                        throw new RuntimeException();
+                    }
+                    break;
+                } catch (SlotIntegrityException e) {
+                }
+            }
+
+            if (masterKey == null) {
+                throw new SlotIntegrityException();
+            }
+
+            setKey(masterKey);
+        } catch (SlotIntegrityException e) {
+            showError();
+        } catch (Exception e) {
+            throw new UndeclaredThrowableException(e);
+        }
+    }
+
+    private void setKey(MasterKey key) {
         // send the master key back to the main activity
         Intent result = new Intent();
         result.putExtra("key", key);
@@ -153,15 +186,7 @@ public class AuthActivity extends AppCompatActivity implements FingerprintUiHelp
 
     @Override
     public void onAuthenticated() {
-        MasterKey key;
+        trySlots(FingerprintSlot.class);
-        FingerprintSlot slot = slots.find(FingerprintSlot.class);
-        try {
-            key = new MasterKey(slot.getKey(fingerCipher));
-        } catch (Exception e) {
-            throw new UndeclaredThrowableException(e);
-        }
-
-        setKey(key);
     }
 
     @Override

app/src/main/java/me/impy/aegis/IntroActivity.java

@@ -109,15 +109,13 @@ public class IntroActivity extends AppIntro {
         }
 
         SlotCollection slots = databaseFile.getSlots();
-        slots.setMasterHash(masterKey.getHash());
-
         if (cryptType != CustomAuthenticationSlide.CRYPT_TYPE_NONE) {
             try {
                 // encrypt the master key with a key derived from the user's password
                 // and add it to the list of slots
                 PasswordSlot slot = new PasswordSlot();
                 Cipher cipher = authenticatedSlide.getCipher(slot);
-                masterKey.encryptSlot(slot, cipher);
+                slots.encrypt(slot, masterKey, cipher);
                 slots.add(slot);
             } catch (Exception e) {
                 setException(e);
@@ -131,7 +129,7 @@ public class IntroActivity extends AppIntro {
                 // and add it to the list of slots
                 FingerprintSlot slot = new FingerprintSlot();
                 Cipher cipher = authenticatedSlide.getCipher(slot);
-                masterKey.encryptSlot(slot, cipher);
+                slots.encrypt(slot, masterKey, cipher);
                 slots.add(slot);
             } catch (Exception e) {
                 setException(e);

app/src/main/java/me/impy/aegis/crypto/MasterKey.java

@@ -12,8 +12,6 @@ import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.SecretKey;
 
-import me.impy.aegis.crypto.slots.Slot;
-
 public class MasterKey implements Serializable {
     private SecretKey _key;
 
@@ -28,16 +26,6 @@ public class MasterKey implements Serializable {
         return new MasterKey(CryptoUtils.generateKey());
     }
 
-    public void encryptSlot(Slot slot, Cipher cipher)
-            throws BadPaddingException, IllegalBlockSizeException {
-        slot.setKey(_key, cipher);
-    }
-
-    public static MasterKey decryptSlot(Slot slot, Cipher cipher)
-            throws BadPaddingException, IllegalBlockSizeException, NoSuchAlgorithmException {
-        return new MasterKey(slot.getKey(cipher));
-    }
-
     public CryptResult encrypt(byte[] bytes)
             throws InvalidAlgorithmParameterException, NoSuchAlgorithmException, InvalidKeyException,
             NoSuchPaddingException, BadPaddingException, IllegalBlockSizeException {
@@ -55,4 +43,8 @@ public class MasterKey implements Serializable {
     public byte[] getHash() {
         return CryptoUtils.hashKey(_key);
     }
+
+    public byte[] getBytes() {
+        return _key.getEncoded();
+    }
 }

app/src/main/java/me/impy/aegis/crypto/slots/Slot.java

@@ -14,6 +14,7 @@ import javax.crypto.SecretKey;
 import javax.crypto.spec.SecretKeySpec;
 
 import me.impy.aegis.crypto.CryptoUtils;
+import me.impy.aegis.crypto.MasterKey;
 
 public abstract class Slot implements Serializable {
     public final static byte TYPE_RAW = 0x00;
@@ -31,8 +32,8 @@ public abstract class Slot implements Serializable {
     }
 
     // setKey encrypts the given master key with the given key and stores the result in this slot.
-    public void setKey(SecretKey masterKey, Cipher cipher) throws BadPaddingException, IllegalBlockSizeException {
+    public void setKey(MasterKey masterKey, Cipher cipher) throws BadPaddingException, IllegalBlockSizeException {
-        byte[] masterKeyBytes = masterKey.getEncoded();
+        byte[] masterKeyBytes = masterKey.getBytes();
         _encryptedMasterKey = cipher.doFinal(masterKeyBytes);
         CryptoUtils.zero(masterKeyBytes);
     }

app/src/main/java/me/impy/aegis/crypto/slots/SlotCollection.java

@@ -1,13 +1,19 @@
 package me.impy.aegis.crypto.slots;
 
 import java.io.Serializable;
+import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.SecretKey;
 
 import me.impy.aegis.crypto.CryptoUtils;
+import me.impy.aegis.crypto.MasterKey;
 import me.impy.aegis.util.LittleByteBuffer;
 
 public class SlotCollection implements Iterable<Slot>, Serializable {
@@ -88,6 +94,16 @@ public class SlotCollection implements Iterable<Slot>, Serializable {
         return null;
     }
 
+    public <T extends Slot> List<T> findAll(Class<T> type) {
+        ArrayList<T> list = new ArrayList<>();
+        for (Slot slot : this) {
+            if (slot.getClass() == type) {
+                list.add(type.cast(slot));
+            }
+        }
+        return list;
+    }
+
     public <T extends Slot> boolean has(Class<T> type) {
         return find(type) != null;
     }
@@ -97,11 +113,27 @@ public class SlotCollection implements Iterable<Slot>, Serializable {
         return _slots.iterator();
     }
 
-    public void setMasterHash(byte[] masterHash) {
+    public void encrypt(Slot slot, MasterKey key, Cipher cipher)
+            throws BadPaddingException, IllegalBlockSizeException {
+        slot.setKey(key, cipher);
+        setMasterHash(key.getHash());
+    }
+
+    public MasterKey decrypt(Slot slot, Cipher cipher)
+            throws SlotIntegrityException, BadPaddingException, IllegalBlockSizeException {
+        byte[] hash = getMasterHash();
+        MasterKey key = new MasterKey(slot.getKey(cipher));
+        if (!Arrays.equals(hash, key.getHash())) {
+            throw new SlotIntegrityException();
+        }
+        return key;
+    }
+
+    private void setMasterHash(byte[] masterHash) {
         _masterHash = masterHash;
     }
 
-    public byte[] getMasterHash() {
+    private byte[] getMasterHash() {
         return _masterHash;
     }
 }

app/src/main/java/me/impy/aegis/crypto/slots/SlotIntegrityException.java

@@ -0,0 +1,5 @@
+package me.impy.aegis.crypto.slots;
+
+public class SlotIntegrityException extends Exception {
+
+}

app/src/main/java/me/impy/aegis/helpers/AuthHelper.java

@@ -34,5 +34,4 @@ public class AuthHelper {
         CryptoUtils.zero(passwordConfirm);
         return equal;
     }
-
 }