Merge "Ensure backup doesn't reuse ack tokens nearby in time" into oc-dr1-dev
am: 672f578fd1
Change-Id: I110ab6b96ac3fd866ace40fbe47614e2ad73a787
diff --git a/services/backup/java/com/android/server/backup/BackupManagerService.java b/services/backup/java/com/android/server/backup/BackupManagerService.java
index a028028..41de97c 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerService.java
@@ -698,6 +698,7 @@
final SparseArray<Operation> mCurrentOperations = new SparseArray<Operation>();
final Object mCurrentOpLock = new Object();
final Random mTokenGenerator = new Random();
+ final AtomicInteger mNextToken = new AtomicInteger();
final SparseArray<AdbParams> mAdbBackupRestoreConfirmations = new SparseArray<AdbParams>();
@@ -770,15 +771,13 @@
@GuardedBy("mQueueLock")
ArrayList<FullBackupEntry> mFullBackupQueue;
- // Utility: build a new random integer token
+ // Utility: build a new random integer token. The low bits are the ordinal of the
+ // operation for near-time uniqueness, and the upper bits are random for app-
+ // side unpredictability.
@Override
public int generateRandomIntegerToken() {
- int token;
- do {
- synchronized (mTokenGenerator) {
- token = mTokenGenerator.nextInt();
- }
- } while (token < 0);
+ int token = mTokenGenerator.nextInt() & ~0xFF;
+ token |= (mNextToken.incrementAndGet() & 0xFF);
return token;
}