Stop regenerating secret key for each package

app/src/main/java/com/stevesoltys/backup/security/CipherUtil.java

@@ -5,7 +5,6 @@ import javax.crypto.spec.IvParameterSpec;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
-import java.security.spec.InvalidKeySpecException;
 
 /**
  * A utility class for encrypting and decrypting data using a {@link Cipher}.
@@ -19,39 +18,35 @@ public class CipherUtil {
      */
     public static final String CIPHER_ALGORITHM = "AES/CFB/PKCS5Padding";
 
-    /**
+    /**.
-     * Encrypts the given payload using a key generated from the provided password and salt.
+     * Encrypts the given payload using the provided secret key.
      *
      * @param payload  The payload.
-     * @param password The password.
+     * @param secretKey The secret key.
-     * @param salt     The salt.
+     * @param iv        The initialization vector.
      */
-    public static byte[] encrypt(byte[] payload, String password, byte[] salt) throws NoSuchPaddingException,
+    public static byte[] encrypt(byte[] payload, SecretKey secretKey, byte[] iv) throws NoSuchPaddingException,
-            NoSuchAlgorithmException, InvalidKeySpecException, BadPaddingException, IllegalBlockSizeException,
+            NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException,
             InvalidAlgorithmParameterException, InvalidKeyException {
 
-        SecretKey secretKey = KeyGenerator.generate(password, salt);
         Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
-        cipher.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(salt));
+        cipher.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(iv));
-
         return cipher.doFinal(payload);
     }
 
     /**
-     * Decrypts the given payload using a key generated from the provided password and salt.
+     * Decrypts the given payload using the provided secret key.
      *
      * @param payload   The payload.
-     * @param password The password.
+     * @param secretKey The secret key.
-     * @param salt     The salt.
+     * @param iv        The initialization vector.
      */
-    public static byte[] decrypt(byte[] payload, String password, byte[] salt) throws NoSuchPaddingException,
+    public static byte[] decrypt(byte[] payload, SecretKey secretKey, byte[] iv) throws NoSuchPaddingException,
-            NoSuchAlgorithmException, InvalidKeySpecException, BadPaddingException, IllegalBlockSizeException,
+            NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException,
             InvalidAlgorithmParameterException, InvalidKeyException {
 
-        SecretKey secretKey = KeyGenerator.generate(password, salt);
         Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
-        cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(salt));
+        cipher.init(Cipher.DECRYPT_MODE, secretKey, new IvParameterSpec(iv));
-
         return cipher.doFinal(payload);
     }
 }

app/src/main/java/com/stevesoltys/backup/transport/component/provider/ContentProviderBackupComponent.java

@@ -7,10 +7,12 @@ import android.os.ParcelFileDescriptor;
 import android.util.Base64;
 import android.util.Log;
 import com.stevesoltys.backup.security.CipherUtil;
+import com.stevesoltys.backup.security.KeyGenerator;
 import com.stevesoltys.backup.transport.component.BackupComponent;
 import libcore.io.IoUtils;
 import org.apache.commons.io.IOUtils;
 
+import javax.crypto.SecretKey;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -209,13 +211,23 @@ public class ContentProviderBackupComponent implements BackupComponent {
         clearBackupState(false);
     }
 
-    private void initializeBackupState() throws IOException {
+    private void initializeBackupState() throws Exception {
         if (backupState == null) {
             backupState = new ContentProviderBackupState();
         }
 
         if (backupState.getOutputStream() == null) {
             initializeOutputStream();
+
+            ZipEntry saltZipEntry = new ZipEntry(ContentProviderBackupConstants.SALT_FILE_PATH);
+            backupState.getOutputStream().putNextEntry(saltZipEntry);
+            backupState.getOutputStream().write(backupState.getSalt());
+            backupState.getOutputStream().closeEntry();
+
+
+            if (configuration.getPassword() != null && !configuration.getPassword().isEmpty()) {
+                backupState.setSecretKey(KeyGenerator.generate(configuration.getPassword(), backupState.getSalt()));
+            }
         }
     }
 
@@ -227,11 +239,6 @@ public class ContentProviderBackupComponent implements BackupComponent {
         FileOutputStream fileOutputStream = new FileOutputStream(outputFileDescriptor.getFileDescriptor());
         ZipOutputStream zipOutputStream = new ZipOutputStream(fileOutputStream);
         backupState.setOutputStream(zipOutputStream);
-
-        ZipEntry saltZipEntry = new ZipEntry(ContentProviderBackupConstants.SALT_FILE_PATH);
-        zipOutputStream.putNextEntry(saltZipEntry);
-        zipOutputStream.write(backupState.getSalt());
-        zipOutputStream.closeEntry();
     }
 
     private int transferIncrementalBackupData(BackupDataInput backupDataInput) throws IOException {
@@ -257,13 +264,12 @@ public class ContentProviderBackupComponent implements BackupComponent {
                 backupDataInput.readEntityData(buffer, 0, dataSize);
 
                 try {
-                    if (configuration.getPassword() != null && !configuration.getPassword().isEmpty()) {
+                    if (backupState.getSecretKey() != null) {
-
                         byte[] payload = Arrays.copyOfRange(buffer, 0, dataSize);
-                        String password = configuration.getPassword();
+                        SecretKey secretKey = backupState.getSecretKey();
                         byte[] salt = backupState.getSalt();
 
-                        outputStream.write(CipherUtil.encrypt(payload, password, salt));
+                        outputStream.write(CipherUtil.encrypt(payload, secretKey, salt));
 
                     } else {
                         outputStream.write(buffer, 0, dataSize);

app/src/main/java/com/stevesoltys/backup/transport/component/provider/ContentProviderBackupState.java

@@ -2,6 +2,7 @@ package com.stevesoltys.backup.transport.component.provider;
 
 import android.os.ParcelFileDescriptor;
 
+import javax.crypto.SecretKey;
 import java.io.InputStream;
 import java.security.SecureRandom;
 import java.util.zip.ZipOutputStream;
@@ -29,6 +30,8 @@ class ContentProviderBackupState {
 
     private byte[] salt;
 
+    private SecretKey secretKey;
+
     public ContentProviderBackupState() {
         salt = new byte[16];
         SECURE_RANDOM.nextBytes(salt);
@@ -93,4 +96,12 @@ class ContentProviderBackupState {
     byte[] getSalt() {
         return salt;
     }
+
+    public SecretKey getSecretKey() {
+        return secretKey;
+    }
+
+    public void setSecretKey(SecretKey secretKey) {
+        this.secretKey = secretKey;
+    }
 }

app/src/main/java/com/stevesoltys/backup/transport/component/provider/ContentProviderRestoreComponent.java

@@ -15,10 +15,10 @@ import com.stevesoltys.backup.transport.component.RestoreComponent;
 import libcore.io.IoUtils;
 import libcore.io.Streams;
 
-import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
-import javax.crypto.spec.IvParameterSpec;
 import java.io.*;
+import java.util.LinkedList;
+import java.util.List;
 import java.util.Optional;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
@@ -59,15 +59,37 @@ public class ContentProviderRestoreComponent implements RestoreComponent {
                 seekToEntry(inputStream, ContentProviderBackupConstants.SALT_FILE_PATH);
 
                 restoreState.setSalt(Streams.readFullyNoClose(inputStream));
+                restoreState.setSecretKey(KeyGenerator.generate(configuration.getPassword(), restoreState.getSalt()));
 
                 IoUtils.closeQuietly(inputFileDescriptor);
                 IoUtils.closeQuietly(inputStream);
 
-            } catch (IOException ex) {
+            } catch (Exception ex) {
                 Log.e(TAG, "Salt not found", ex);
             }
         }
 
+        try {
+            List<ZipEntry> zipEntries = new LinkedList<>();
+
+            ParcelFileDescriptor inputFileDescriptor = buildInputFileDescriptor();
+            ZipInputStream inputStream = buildInputStream(inputFileDescriptor);
+
+            ZipEntry zipEntry;
+            while ((zipEntry = inputStream.getNextEntry()) != null) {
+                zipEntries.add(zipEntry);
+                inputStream.closeEntry();
+            }
+
+            IoUtils.closeQuietly(inputFileDescriptor);
+            IoUtils.closeQuietly(inputStream);
+
+            restoreState.setZipEntries(zipEntries);
+
+        } catch (Exception ex) {
+            Log.e(TAG, "Salt not found", ex);
+        }
+
         return TRANSPORT_OK;
     }
 
@@ -82,7 +104,6 @@ public class ContentProviderRestoreComponent implements RestoreComponent {
             restoreState.setPackageIndex(packageIndex);
             String name = packages[packageIndex].packageName;
 
-            try {
             if (containsPackageFile(configuration.getIncrementalBackupDirectory() + name)) {
                 restoreState.setRestoreType(TYPE_KEY_VALUE);
                 return new RestoreDescription(name, restoreState.getRestoreType());
@@ -91,45 +112,13 @@ public class ContentProviderRestoreComponent implements RestoreComponent {
                 restoreState.setRestoreType(TYPE_FULL_STREAM);
                 return new RestoreDescription(name, restoreState.getRestoreType());
             }
-
-            } catch (IOException ex) {
-                Log.e(TAG, "Error choosing package  " + name + "  at index " + packageIndex + "failed selection:", ex);
-            }
         }
         return RestoreDescription.NO_MORE_PACKAGES;
     }
 
-    private boolean containsPackageFile(String fileName) throws IOException {
+    private boolean containsPackageFile(String fileName) {
-        ParcelFileDescriptor inputFileDescriptor = buildInputFileDescriptor();
+        return restoreState.getZipEntries().stream()
-        ZipInputStream inputStream = buildInputStream(inputFileDescriptor);
+                .anyMatch(zipEntry -> zipEntry.getName().startsWith(fileName));
-
-        Optional<ZipEntry> zipEntry = seekToEntry(inputStream, fileName);
-        IoUtils.closeQuietly(inputFileDescriptor);
-        IoUtils.closeQuietly(inputStream);
-        return zipEntry.isPresent();
-    }
-
-    private ParcelFileDescriptor buildInputFileDescriptor() throws FileNotFoundException {
-        ContentResolver contentResolver = configuration.getContext().getContentResolver();
-        return contentResolver.openFileDescriptor(configuration.getUri(), "r");
-    }
-
-    private ZipInputStream buildInputStream(ParcelFileDescriptor inputFileDescriptor) throws FileNotFoundException {
-        FileInputStream fileInputStream = new FileInputStream(inputFileDescriptor.getFileDescriptor());
-        return new ZipInputStream(fileInputStream);
-    }
-
-    private Optional<ZipEntry> seekToEntry(ZipInputStream inputStream, String entryPath) throws IOException {
-        ZipEntry zipEntry;
-        while ((zipEntry = inputStream.getNextEntry()) != null) {
-
-            if (zipEntry.getName().startsWith(entryPath)) {
-                return Optional.of(zipEntry);
-            }
-            inputStream.closeEntry();
-        }
-
-        return Optional.empty();
     }
 
     @Override
@@ -177,14 +166,36 @@ public class ContentProviderRestoreComponent implements RestoreComponent {
         return TRANSPORT_OK;
     }
 
+    private ParcelFileDescriptor buildInputFileDescriptor() throws FileNotFoundException {
+        ContentResolver contentResolver = configuration.getContext().getContentResolver();
+        return contentResolver.openFileDescriptor(configuration.getUri(), "r");
+    }
+
+    private ZipInputStream buildInputStream(ParcelFileDescriptor inputFileDescriptor) throws FileNotFoundException {
+        FileInputStream fileInputStream = new FileInputStream(inputFileDescriptor.getFileDescriptor());
+        return new ZipInputStream(fileInputStream);
+    }
+
+    private Optional<ZipEntry> seekToEntry(ZipInputStream inputStream, String entryPath) throws IOException {
+        ZipEntry zipEntry;
+        while ((zipEntry = inputStream.getNextEntry()) != null) {
+
+            if (zipEntry.getName().startsWith(entryPath)) {
+                return Optional.of(zipEntry);
+            }
+            inputStream.closeEntry();
+        }
+
+        return Optional.empty();
+    }
+
     private byte[] readBackupData(ZipInputStream inputStream) throws Exception {
         byte[] backupData = Streams.readFullyNoClose(inputStream);
+        SecretKey secretKey = restoreState.getSecretKey();
+        byte[] initializationVector = restoreState.getSalt();
 
-        String password = configuration.getPassword();
+        if (secretKey != null) {
-        byte[] salt = restoreState.getSalt();
+            backupData = CipherUtil.decrypt(backupData, secretKey, initializationVector);
-
-        if (password != null && !password.isEmpty() && salt != null) {
-            backupData = CipherUtil.decrypt(backupData, password, salt);
         }
 
         return backupData;

app/src/main/java/com/stevesoltys/backup/transport/component/provider/ContentProviderRestoreState.java

@@ -3,6 +3,9 @@ package com.stevesoltys.backup.transport.component.provider;
 import android.content.pm.PackageInfo;
 import android.os.ParcelFileDescriptor;
 
+import javax.crypto.SecretKey;
+import java.util.List;
+import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
 /**
@@ -22,6 +25,10 @@ class ContentProviderRestoreState {
 
     private byte[] salt;
 
+    private SecretKey secretKey;
+
+    private List<ZipEntry> zipEntries;
+
     ParcelFileDescriptor getInputFileDescriptor() {
         return inputFileDescriptor;
     }
@@ -69,4 +76,20 @@ class ContentProviderRestoreState {
     void setSalt(byte[] salt) {
         this.salt = salt;
     }
+
+    public SecretKey getSecretKey() {
+        return secretKey;
+    }
+
+    public void setSecretKey(SecretKey secretKey) {
+        this.secretKey = secretKey;
+    }
+
+    public List<ZipEntry> getZipEntries() {
+        return zipEntries;
+    }
+
+    public void setZipEntries(List<ZipEntry> zipEntries) {
+        this.zipEntries = zipEntries;
+    }
 }