Add temp repository encryption (#131)

2018-12-13 10:27:07 +01:00
parent fa30beb9d5
commit f3d51f0cb9
9 changed files with 160 additions and 6 deletions
@@ -88,4 +88,5 @@ dependencies {
    implementation 'com.github.apl-devs:appintro:v4.2.3'

    implementation project(':syncthing-repository-android')
+    implementation project(':syncthing-temp-repository-encryption')
 }
@@ -8,6 +8,7 @@ import kotlinx.coroutines.launch
 import net.syncthing.java.client.SyncthingClient
 import net.syncthing.java.core.configuration.Configuration
 import net.syncthing.java.core.exception.ExceptionReport
+import net.syncthing.java.repository.EncryptedTempRepository
 import net.syncthing.repository.android.SqliteIndexRepository
 import net.syncthing.repository.android.TempDirectoryLocalRepository
 import net.syncthing.repository.android.database.RepositoryDatabase
@@ -49,7 +50,11 @@ class LibraryInstance (
        }
    }

-    private val tempRepository = TempDirectoryLocalRepository(File(context.filesDir, "temp_repository"))
+    private val tempRepository = EncryptedTempRepository(
+            TempDirectoryLocalRepository(
+                    File(context.filesDir, "temp_repository")
+            )
+    )

    val isListeningPortTaken = checkIsListeningPortTaken()  // this must come first to work correctly
    val configuration = Configuration(configFolder = context.filesDir)
@@ -58,7 +63,7 @@ class LibraryInstance (
            repository = SqliteIndexRepository(
                    database = RepositoryDatabase.with(context),
                    closeDatabaseOnClose = false,
-                    clearTempStorageHook = { tempRepository.deleteAllData() }
+                    clearTempStorageHook = { tempRepository.deleteAllTempData() }
            ),
            tempRepository = tempRepository,
            exceptionReportHandler = { ex ->
@@ -1 +1 @@
-include ':app', ':syncthing-repository-android', ':syncthing-repository-default', ':syncthing-relay-client', ':syncthing-bep', ':syncthing-core', ':syncthing-client', ':syncthing-discovery', ':syncthing-client-cli'
+include ':app', ':syncthing-repository-android', ':syncthing-repository-default', ':syncthing-relay-client', ':syncthing-bep', ':syncthing-core', ':syncthing-client', ':syncthing-discovery', ':syncthing-client-cli', ':syncthing-temp-repository-encryption'
@@ -1,5 +1,6 @@
 /* 
 * Copyright (C) 2016 Davide Imbriaco
+ * Copyright (C) 2018 Jonas Lochmann
 *
 * This Java file is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -22,4 +23,6 @@ interface TempRepository: Closeable {
    fun popTempData(key: String): ByteArray

    fun deleteTempData(keys: List<String>)
+
+    fun deleteAllTempData()
 }
@@ -1,3 +1,16 @@
+/*
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package net.syncthing.repository.android

 import net.syncthing.java.core.interfaces.TempRepository
@@ -14,7 +27,7 @@ class TempDirectoryLocalRepository(private val directory: File): TempRepository
        directory.mkdirs()

        // there could be garbage from the previous session which we don't need anymore
-        deleteAllData()
+        deleteAllTempData()
    }

    override fun pushTempData(data: ByteArray): String {
@@ -59,10 +72,10 @@ class TempDirectoryLocalRepository(private val directory: File): TempRepository
    }

    override fun close() {
-        deleteAllData()
+        deleteAllTempData()
    }

-    fun deleteAllData() {
+    override fun deleteAllTempData() {
        directory.listFiles().forEach { file ->
            if (file.isFile) {
                file.delete()
@@ -1,5 +1,6 @@
 /* 
 * Copyright (C) 2016 Davide Imbriaco
+ * Copyright (C) 2018 Jonas Lochmann
 *
 * This Java file is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -227,6 +228,14 @@ class SqlRepository(databaseFolder: File) : Closeable, IndexRepository, TempRepo
        }
    }

+    override fun deleteAllTempData() {
+        getConnection().use { connection ->
+            connection.prepareStatement("DELETE FROM temporary_data").use { statement ->
+                statement.executeUpdate()
+            }
+        }
+    }
+
    companion object {
        private const val VERSION = 13
    }
@@ -0,0 +1,10 @@
+apply plugin: 'java-library'
+apply plugin: 'kotlin'
+
+dependencies {
+    implementation (project(':syncthing-core')) {
+        exclude group: 'commons-logging', module:'commons-logging'
+        exclude group: 'org.slf4j'
+        exclude group: 'ch.qos.logback'
+    }
+}
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.repository
+
+import net.syncthing.java.core.interfaces.TempRepository
+import java.io.IOException
+import java.security.MessageDigest
+import java.security.SecureRandom
+import java.util.*
+import javax.crypto.Cipher
+import javax.crypto.spec.GCMParameterSpec
+import javax.crypto.spec.SecretKeySpec
+
+class EncryptedTempRepository(private val otherRepository: TempRepository): TempRepository {
+    companion object {
+        private val secureRandom = SecureRandom()
+    }
+
+    private val keyStorage = Collections.synchronizedMap(mutableMapOf<String, EncryptedTempRepositoryItem>())
+
+    override fun pushTempData(data: ByteArray): String {
+        val (encrypted, config) = encrypt(data)
+        val key = otherRepository.pushTempData(encrypted)
+
+        keyStorage[key] = config
+
+        return key
+    }
+
+    override fun popTempData(key: String) = decrypt(otherRepository.popTempData(key), keyStorage.remove(key)!!)
+
+    override fun deleteTempData(keys: List<String>) {
+        keys.forEach { keyStorage.remove(it) }
+        otherRepository.deleteTempData(keys)
+    }
+
+    override fun deleteAllTempData() {
+        keyStorage.clear()
+        otherRepository.deleteAllTempData()
+    }
+
+    override fun close() {
+        keyStorage.clear()
+        otherRepository.close()
+    }
+
+    private fun encrypt(input: ByteArray): Pair<ByteArray, EncryptedTempRepositoryItem> {
+        val cryptoSpec = EncryptedTempRepositoryItem(
+                key = ByteArray(16).apply { secureRandom.nextBytes(this) },
+                iv = ByteArray(16).apply { secureRandom.nextBytes(this) },
+                sha512 = sha512(input)
+        )
+
+        val output = Cipher.getInstance("AES/GCM/NoPadding").apply {
+            init(
+                    Cipher.ENCRYPT_MODE,
+                    SecretKeySpec(cryptoSpec.key, "AES"),
+                    GCMParameterSpec(128, cryptoSpec.iv)
+            )
+        }.doFinal(input)
+
+        return output to cryptoSpec
+    }
+
+    private fun decrypt(input: ByteArray, config: EncryptedTempRepositoryItem): ByteArray {
+        val output = Cipher.getInstance("AES/GCM/NoPadding").apply {
+            init(
+                    Cipher.DECRYPT_MODE,
+                    SecretKeySpec(config.key, "AES"),
+                    GCMParameterSpec(128, config.iv)
+            )
+        }.doFinal(input)
+
+        if (!sha512(output).contentEquals(config.sha512)) {
+            throw IOException("temporarily file was modified")
+        }
+
+        return output
+    }
+
+    private fun sha512(data: ByteArray): ByteArray = MessageDigest.getInstance("SHA-512").digest(data)
+}
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2018 Jonas Lochmann
+ *
+ * This Java file is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.syncthing.java.repository
+
+internal class EncryptedTempRepositoryItem(
+        val iv: ByteArray,
+        val key: ByteArray,
+        val sha512: ByteArray
+)