Journal: use journal keys if available.

If a journal has a key set to it (usually used for shared journals), use
it instead of the symmetric key. The key of the journal is asymmetrically
encrypted using our keypair.

app/src/main/java/com/etesync/syncadapter/journalmanager/Crypto.java

@@ -123,8 +123,21 @@ public class Crypto {
         private SecureRandom _random = null;
         @Getter
         private final byte version;
-        private final byte[] cipherKey;
+        private byte[] cipherKey;
-        private final byte[] hmacKey;
+        private byte[] hmacKey;
+
+        private void setDerivedKey(byte[] derivedKey) {
+            cipherKey = hmac256("aes".getBytes(Charsets.UTF_8), derivedKey);
+            hmacKey = hmac256("hmac".getBytes(Charsets.UTF_8), derivedKey);
+        }
+
+        public CryptoManager(int version, AsymmetricKeyPair keyPair, byte[] encryptedKey) {
+            Crypto.AsymmetricCryptoManager cryptoManager = new Crypto.AsymmetricCryptoManager(keyPair);
+            byte[] derivedKey = cryptoManager.decrypt(encryptedKey);
+
+            this.version = (byte) version;
+            setDerivedKey(derivedKey);
+        }
 
         public CryptoManager(int version, @NonNull String keyBase64, @NonNull String salt) throws Exceptions.IntegrityException, Exceptions.VersionTooNewException {
             byte[] derivedKey;
@@ -139,8 +152,7 @@ public class Crypto {
             }
 
             this.version = (byte) version;
-            cipherKey = hmac256("aes".getBytes(Charsets.UTF_8), derivedKey);
+            setDerivedKey(derivedKey);
-            hmacKey = hmac256("hmac".getBytes(Charsets.UTF_8), derivedKey);
         }
 
         private static final int blockSize = 16; // AES's block size in bytes

app/src/main/java/com/etesync/syncadapter/journalmanager/JournalManager.java

@@ -40,7 +40,7 @@ public class JournalManager extends BaseManager {
         this.client = httpClient;
     }
 
-    public List<Journal> getJournals(String keyBase64) throws Exceptions.HttpException, Exceptions.IntegrityException, Exceptions.GenericCryptoException {
+    public List<Journal> getJournals() throws Exceptions.HttpException {
         Request request = new Request.Builder()
                 .get()
                 .url(remote)
@@ -51,9 +51,7 @@ public class JournalManager extends BaseManager {
         List<Journal> ret = GsonHelper.gson.fromJson(body.charStream(), journalType);
 
         for (Journal journal : ret) {
-            Crypto.CryptoManager crypto = new Crypto.CryptoManager(journal.getVersion(), keyBase64, journal.getUid());
             journal.processFromJson();
-            journal.verify(crypto);
         }
 
         return ret;
@@ -157,7 +155,7 @@ public class JournalManager extends BaseManager {
             setContent(Arrays.copyOfRange(getContent(), HMAC_SIZE, getContent().length));
         }
 
-        void verify(Crypto.CryptoManager crypto) throws Exceptions.IntegrityException {
+        public void verify(Crypto.CryptoManager crypto) throws Exceptions.IntegrityException {
             if (hmac == null) {
                 throw new Exceptions.IntegrityException("HMAC is null!");
             }

app/src/main/java/com/etesync/syncadapter/syncadapter/SyncAdapterService.java

@@ -158,8 +158,16 @@ public abstract class SyncAdapterService extends Service {
 
                     List<Pair<JournalManager.Journal, CollectionInfo>> journals = new LinkedList<>();
 
-                    for (JournalManager.Journal journal : journalsManager.getJournals(settings.password())) {
+                    for (JournalManager.Journal journal : journalsManager.getJournals()) {
-                        Crypto.CryptoManager crypto = new Crypto.CryptoManager(journal.getVersion(), settings.password(), journal.getUid());
+                        Crypto.CryptoManager crypto;
+                        if (journal.getKey() != null) {
+                            crypto = new Crypto.CryptoManager(journal.getVersion(), settings.getKeyPair(), journal.getKey());
+                        } else {
+                            crypto = new Crypto.CryptoManager(journal.getVersion(), settings.password(), journal.getUid());
+                        }
+
+                        journal.verify(crypto);
+
                         CollectionInfo info = CollectionInfo.fromJson(journal.getContent(crypto));
                         info.updateFromJournal(journal);
 

app/src/main/java/com/etesync/syncadapter/syncadapter/SyncManager.java

@@ -33,6 +33,7 @@ import com.etesync.syncadapter.model.SyncEntry;
 import com.etesync.syncadapter.resource.LocalCollection;
 import com.etesync.syncadapter.resource.LocalResource;
 import com.etesync.syncadapter.ui.DebugInfoActivity;
+import com.etesync.syncadapter.utils.Base64;
 
 import org.apache.commons.collections4.ListUtils;
 
@@ -118,7 +119,12 @@ abstract public class SyncManager {
         notificationManager.cancel();
 
         App.log.info(String.format(Locale.getDefault(), "Syncing collection %s (version: %d)", journalUid, info.version));
-        crypto = new Crypto.CryptoManager(info.version, settings.password(), journalUid);
+
+        if (getJournalEntity().getEncryptedKey() != null) {
+            crypto = new Crypto.CryptoManager(info.version, settings.getKeyPair(), getJournalEntity().getEncryptedKey());
+        } else {
+            crypto = new Crypto.CryptoManager(info.version, settings.password(), info.uid);
+        }
     }
 
     protected abstract int notificationId();
@@ -235,7 +241,7 @@ abstract public class SyncManager {
 
     private JournalEntity getJournalEntity() {
         if (_journalEntity == null)
-            _journalEntity = JournalModel.Journal.fetch(data, info.getServiceEntity(data), journal.getUid());
+            _journalEntity = JournalModel.Journal.fetch(data, info.getServiceEntity(data), info.uid);
         return _journalEntity;
     }
 

app/src/test/java/com/etesync/syncadapter/journalmanager/ServiceTest.java

@@ -93,7 +93,7 @@ public class ServiceTest {
         }
         assertNotNull(caught);
 
-        List<JournalManager.Journal> journals = journalManager.getJournals(Helpers.keyBase64);
+        List<JournalManager.Journal> journals = journalManager.getJournals();
         assertEquals(journals.size(), 1);
         CollectionInfo info2 = CollectionInfo.fromJson(journals.get(0).getContent(crypto));
         assertEquals(info2.displayName, info.displayName);
@@ -103,7 +103,7 @@ public class ServiceTest {
         journal = new JournalManager.Journal(crypto, info.toJson(), info.uid);
         journalManager.updateJournal(journal);
 
-        journals = journalManager.getJournals(Helpers.keyBase64);
+        journals = journalManager.getJournals();
         assertEquals(journals.size(), 1);
         info2 = CollectionInfo.fromJson(journals.get(0).getContent(crypto));
         assertEquals(info2.displayName, info.displayName);
@@ -111,7 +111,7 @@ public class ServiceTest {
         // Delete journal
         journalManager.deleteJournal(journal);
 
-        journals = journalManager.getJournals(Helpers.keyBase64);
+        journals = journalManager.getJournals();
         assertEquals(journals.size(), 0);
 
         // Bad HMAC
@@ -124,7 +124,10 @@ public class ServiceTest {
 
         try {
             caught = null;
-            journalManager.getJournals(Helpers.keyBase64);
+            for (JournalManager.Journal journal1 : journalManager.getJournals()) {
+                Crypto.CryptoManager crypto1 = new Crypto.CryptoManager(info.version, Helpers.keyBase64, journal1.getUid());
+                journal1.verify(crypto1);
+            }
         } catch (Exceptions.IntegrityException e) {
             caught = e;
         }