From 96ad5160e59719b870826e93fa7d17898a0e6dfc Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Tue, 10 Jan 2023 19:38:51 +0000
Subject: [PATCH] LockSettingsStorage: gracefully handle null keys in database

Bug: 261860102
Test: com.android.server.locksettings
Change-Id: I7606dad85826d82d663a701e9e7bccb9d908da98
---
 .../server/locksettings/LockSettingsStorage.java   |  8 ++++++--
 .../locksettings/LockSettingsStorageTests.java     | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/locksettings/LockSettingsStorage.java b/services/core/java/com/android/server/locksettings/LockSettingsStorage.java
index 2c28af1cc6183..434c0d7f955ae 100644
--- a/services/core/java/com/android/server/locksettings/LockSettingsStorage.java
+++ b/services/core/java/com/android/server/locksettings/LockSettingsStorage.java
@@ -62,6 +62,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 /**
  * Storage for the lock settings service.
@@ -886,12 +887,15 @@ class LockSettingsStorage {
                 if (!(obj instanceof CacheKey))
                     return false;
                 CacheKey o = (CacheKey) obj;
-                return userId == o.userId && type == o.type && key.equals(o.key);
+                return userId == o.userId && type == o.type && Objects.equals(key, o.key);
             }
 
             @Override
             public int hashCode() {
-                return key.hashCode() ^ userId ^ type;
+                int hashCode = Objects.hashCode(key);
+                hashCode = 31 * hashCode + userId;
+                hashCode = 31 * hashCode + type;
+                return hashCode;
             }
         }
     }
diff --git a/services/tests/servicestests/src/com/android/server/locksettings/LockSettingsStorageTests.java b/services/tests/servicestests/src/com/android/server/locksettings/LockSettingsStorageTests.java
index 03d5b17d7fa85..05208441e3f2c 100644
--- a/services/tests/servicestests/src/com/android/server/locksettings/LockSettingsStorageTests.java
+++ b/services/tests/servicestests/src/com/android/server/locksettings/LockSettingsStorageTests.java
@@ -265,6 +265,20 @@ public class LockSettingsStorageTests {
         assertEquals("Cached value didn't match stored value", storage, cached);
     }
 
+    @Test
+    public void testNullKey() {
+        mStorage.setString(null, "value", 0);
+
+        // Verify that this doesn't throw an exception.
+        assertEquals("value", mStorage.readKeyValue(null, null, 0));
+
+        // The read that happens as part of prefetchUser shouldn't throw an exception either.
+        mStorage.clearCache();
+        mStorage.prefetchUser(0);
+
+        assertEquals("value", mStorage.readKeyValue(null, null, 0));
+    }
+
     @Test
     public void testRemoveUser() {
         mStorage.writeKeyValue("key", "value", 0);