Use ConnectivityBlobStore as the main storage

mechanism in WifiKeystore.

See aosp/2859045 as an example of using
ConnectivityBlobStore.

The expected behavior per-API is:

 - put: Always write to ConnectivityBlobStore.
 - get: Attempt to get from ConnectivityBlobStore.
        If alias is not found there, try checking
        in LegacyKeystore.
 - remove: Remove alias from both ConnectivityBlobStore
           and LegacyKeystore.
 - list: List aliases from both ConnectivityBlobStore
         and LegacyKeystore. Deduplicate before returning.

Bug: 304553176
Test: atest WifiKeyStoreTest
Test: Manual test - Added test commands to WifiShellCommand
       to test all of the APIs.
Change-Id: I30b7553bf0ca6a76f81f52aa06f67126fffc4127

2 files changed, 90 insertions, 13 deletions

diff --git a/wifi/java/src/android/net/wifi/WifiBlobStore.java b/wifi/java/src/android/net/wifi/WifiBlobStore.java
new file mode 100644
index 000000000000..8bfaae72f932
--- /dev/null
+++ b/wifi/java/src/android/net/wifi/WifiBlobStore.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-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 android.net.wifi;
+
+import com.android.internal.net.ConnectivityBlobStore;
+
+/**
+ * Database blob store for Wifi.
+ * @hide
+ */
+public class WifiBlobStore extends ConnectivityBlobStore {
+    private static final String DB_NAME = "WifiBlobStore.db";
+    private static WifiBlobStore sInstance;
+    private WifiBlobStore() {
+        super(DB_NAME);
+    }
+
+    /** Returns an instance of WifiBlobStore. */
+    public static WifiBlobStore getInstance() {
+        if (sInstance == null) {
+            sInstance = new WifiBlobStore();
+        }
+        return sInstance;
+    }
+}
diff --git a/wifi/java/src/android/net/wifi/WifiKeystore.java b/wifi/java/src/android/net/wifi/WifiKeystore.java
index 1cda0326bf6c..a06d0eeade72 100644
--- a/wifi/java/src/android/net/wifi/WifiKeystore.java
+++ b/wifi/java/src/android/net/wifi/WifiKeystore.java
@@ -18,12 +18,17 @@ package android.net.wifi;
 import android.annotation.NonNull;
 import android.annotation.SuppressLint;
 import android.annotation.SystemApi;
+import android.os.Binder;
 import android.os.Process;
 import android.os.ServiceManager;
 import android.os.ServiceSpecificException;
 import android.security.legacykeystore.ILegacyKeystore;
 import android.util.Log;
 
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
 /**
  * This class allows the storage and retrieval of non-standard Wifi certificate blobs.
  * @hide
@@ -34,7 +39,7 @@ public final class WifiKeystore {
     private static final String TAG = "WifiKeystore";
     private static final String LEGACY_KEYSTORE_SERVICE_NAME = "android.security.legacykeystore";
 
-    private static ILegacyKeystore getService() {
+    private static ILegacyKeystore getLegacyKeystore() {
         return ILegacyKeystore.Stub.asInterface(
                 ServiceManager.checkService(LEGACY_KEYSTORE_SERVICE_NAME));
     }
@@ -54,13 +59,18 @@ public final class WifiKeystore {
     @SystemApi
     @SuppressLint("UnflaggedApi")
     public static boolean put(@NonNull String alias, @NonNull byte[] blob) {
+        // ConnectivityBlobStore uses the calling uid as a key into the DB.
+        // Clear identity to ensure that callers from system apps and the Wifi framework
+        // are able to access the same values.
+        final long identity = Binder.clearCallingIdentity();
         try {
             Log.i(TAG, "put blob. alias " + alias);
-            getService().put(alias, Process.WIFI_UID, blob);
-            return true;
+            return WifiBlobStore.getInstance().put(alias, blob);
         } catch (Exception e) {
             Log.e(TAG, "Failed to put blob.", e);
             return false;
+        } finally {
+            Binder.restoreCallingIdentity(identity);
         }
     }
 
@@ -69,23 +79,31 @@ public final class WifiKeystore {
      * @param alias Name of the blob to retrieve.
      * @return The unstructured blob, that is the blob that was stored using
      *         {@link android.net.wifi.WifiKeystore#put}.
-     *         Returns null if no blob was found.
+     *         Returns empty byte[] if no blob was found.
      * @hide
      */
     @SystemApi
     @SuppressLint("UnflaggedApi")
     public static @NonNull byte[] get(@NonNull String alias) {
+        final long identity = Binder.clearCallingIdentity();
         try {
             Log.i(TAG, "get blob. alias " + alias);
-            return getService().get(alias, Process.WIFI_UID);
+            byte[] blob = WifiBlobStore.getInstance().get(alias);
+            if (blob != null) {
+                return blob;
+            }
+            Log.i(TAG, "Searching for blob in Legacy Keystore");
+            return getLegacyKeystore().get(alias, Process.WIFI_UID);
         } catch (ServiceSpecificException e) {
             if (e.errorCode != ILegacyKeystore.ERROR_ENTRY_NOT_FOUND) {
                 Log.e(TAG, "Failed to get blob.", e);
             }
         } catch (Exception e) {
             Log.e(TAG, "Failed to get blob.", e);
+        } finally {
+            Binder.restoreCallingIdentity(identity);
         }
-        return null;
+        return new byte[0];
     }
 
     /**
@@ -97,17 +115,27 @@ public final class WifiKeystore {
     @SystemApi
     @SuppressLint("UnflaggedApi")
     public static boolean remove(@NonNull String alias) {
+        boolean blobStoreSuccess = false;
+        boolean legacyKsSuccess = false;
+        final long identity = Binder.clearCallingIdentity();
         try {
-            getService().remove(alias, Process.WIFI_UID);
-            return true;
+            Log.i(TAG, "remove blob. alias " + alias);
+            blobStoreSuccess = WifiBlobStore.getInstance().remove(alias);
+            // Legacy Keystore will throw an exception if the alias is not found.
+            getLegacyKeystore().remove(alias, Process.WIFI_UID);
+            legacyKsSuccess = true;
         } catch (ServiceSpecificException e) {
             if (e.errorCode != ILegacyKeystore.ERROR_ENTRY_NOT_FOUND) {
                 Log.e(TAG, "Failed to remove blob.", e);
             }
         } catch (Exception e) {
             Log.e(TAG, "Failed to remove blob.", e);
+        } finally {
+            Binder.restoreCallingIdentity(identity);
         }
-        return false;
+        Log.i(TAG, "Removal status: wifiBlobStore=" + blobStoreSuccess
+                + ", legacyKeystore=" + legacyKsSuccess);
+        return blobStoreSuccess || legacyKsSuccess;
     }
 
     /**
@@ -119,14 +147,24 @@ public final class WifiKeystore {
     @SystemApi
     @SuppressLint("UnflaggedApi")
     public static @NonNull String[] list(@NonNull String prefix) {
+        final long identity = Binder.clearCallingIdentity();
         try {
-            final String[] aliases = getService().list(prefix, Process.WIFI_UID);
-            for (int i = 0; i < aliases.length; ++i) {
-                aliases[i] = aliases[i].substring(prefix.length());
+            // Aliases from WifiBlobStore will be pre-trimmed.
+            final String[] blobStoreAliases = WifiBlobStore.getInstance().list(prefix);
+            final String[] legacyAliases = getLegacyKeystore().list(prefix, Process.WIFI_UID);
+            for (int i = 0; i < legacyAliases.length; ++i) {
+                legacyAliases[i] = legacyAliases[i].substring(prefix.length());
             }
-            return aliases;
+            // Deduplicate aliases before returning.
+            Set<String> uniqueAliases = new HashSet<>();
+            uniqueAliases.addAll(Arrays.asList(blobStoreAliases));
+            uniqueAliases.addAll(Arrays.asList(legacyAliases));
+            String[] uniqueAliasArray = new String[uniqueAliases.size()];
+            return uniqueAliases.toArray(uniqueAliasArray);
         } catch (Exception e) {
             Log.e(TAG, "Failed to list blobs.", e);
+        } finally {
+            Binder.restoreCallingIdentity(identity);
         }
         return new String[0];
     }