Make OP_LEGACY_STORAGE stickiness configurable

OP_LEGACY_STORAGE is sticky for apps targeting <= Q.
This change makes this behaviour configurable via DeviceConfig, by
introducing a new property "legacy_storage_op_sticky" to existing
namespace "storage_native_boot". If the property is set to true, then
we get the default behaviour (app-op sticky for SDK<=Q). If it's set to
true, then the app-op is not sticky for SDK<=Q.

Apps targeting > Q remain unaffected: always not sticky.

Test: manual:
    * adb shell dumpsys appops --package com.android.vending
    * Observe LEGACY_STORAGE mode=allowed
    * adb shell device_config put storage_native_boot legacy_storage_op_sticky false
    * adb reboot
    * adb shell dumpsys appops --package com.android.vending
    * Observe LEGACY_STORAGE mode=ignored
Bug: 151735608
Change-Id: I06d115a0c85c44b5a6d1054f74a00d8fa674dfa7

3 files changed, 25 insertions, 3 deletions

diff --git a/core/java/android/os/storage/StorageManager.java b/core/java/android/os/storage/StorageManager.java
index 1454aac66d21..88ff2b36dbfa 100644
--- a/core/java/android/os/storage/StorageManager.java
+++ b/core/java/android/os/storage/StorageManager.java
@@ -162,7 +162,12 @@ public class StorageManager {
     /** {@hide} */
     public static final String PROP_SETTINGS_FUSE = FeatureFlagUtils.PERSIST_PREFIX
             + FeatureFlagUtils.SETTINGS_FUSE_FLAG;
-
+    /**
+     * Property that determines whether {@link OP_LEGACY_STORAGE} is sticky for
+     * legacy apps.
+     * @hide
+     */
+    public static final String PROP_LEGACY_OP_STICKY = "persist.sys.legacy_storage_sticky";
 
     /** {@hide} */
     public static final String UUID_PRIVATE_INTERNAL = null;
diff --git a/services/core/java/com/android/server/StorageManagerService.java b/services/core/java/com/android/server/StorageManagerService.java
index 2c220d3f8861..095484f9786c 100644
--- a/services/core/java/com/android/server/StorageManagerService.java
+++ b/services/core/java/com/android/server/StorageManagerService.java
@@ -43,6 +43,7 @@ import static android.os.storage.OnObbStateChangeListener.ERROR_PERMISSION_DENIE
 import static android.os.storage.OnObbStateChangeListener.MOUNTED;
 import static android.os.storage.OnObbStateChangeListener.UNMOUNTED;
 import static android.os.storage.StorageManager.PROP_FUSE;
+import static android.os.storage.StorageManager.PROP_LEGACY_OP_STICKY;
 import static android.os.storage.StorageManager.PROP_SETTINGS_FUSE;
 
 import static com.android.internal.util.XmlUtils.readIntAttribute;
@@ -896,6 +897,7 @@ class StorageManagerService extends IStorageManager.Stub
                     refreshIsolatedStorageSettings();
                 }
             });
+        updateLegacyStorageOpSticky();
         // For now, simply clone property when it changes
         DeviceConfig.addOnPropertiesChangedListener(DeviceConfig.NAMESPACE_STORAGE_NATIVE_BOOT,
                 mContext.getMainExecutor(), (properties) -> {
@@ -1757,6 +1759,13 @@ class StorageManagerService extends IStorageManager.Stub
         }
     }
 
+    private void updateLegacyStorageOpSticky() {
+        final boolean propertyValue = DeviceConfig.getBoolean(
+                DeviceConfig.NAMESPACE_STORAGE_NATIVE_BOOT,
+                "legacy_storage_op_sticky", true);
+        SystemProperties.set(PROP_LEGACY_OP_STICKY, propertyValue ? "true" : "false");
+    }
+
     private void start() {
         connectStoraged();
         connectVold();
diff --git a/services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java b/services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java
index 6c18c8d04363..40919d4a0845 100644
--- a/services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java
+++ b/services/core/java/com/android/server/policy/SoftRestrictedPermissionPolicy.java
@@ -26,6 +26,7 @@ import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_INST
 import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_SYSTEM_EXEMPT;
 import static android.content.pm.PackageManager.FLAG_PERMISSION_RESTRICTION_UPGRADE_EXEMPT;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
+import static android.os.storage.StorageManager.PROP_LEGACY_OP_STICKY;
 
 import static java.lang.Integer.min;
 
@@ -36,6 +37,7 @@ import android.content.Context;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
 import android.os.Build;
+import android.os.SystemProperties;
 import android.os.UserHandle;
 import android.os.storage.StorageManagerInternal;
 
@@ -63,6 +65,9 @@ public abstract class SoftRestrictedPermissionPolicy {
                 }
             };
 
+    private static final boolean isLegacyStorageAppOpStickyGlobal = SystemProperties.getBoolean(
+            PROP_LEGACY_OP_STICKY, /*defaultValue*/true);
+
     /**
      * TargetSDK is per package. To make sure two apps int the same shared UID do not fight over
      * what to set, always compute the combined targetSDK.
@@ -136,9 +141,12 @@ public abstract class SoftRestrictedPermissionPolicy {
                     shouldPreserveLegacyExternalStorage = pkg.hasPreserveLegacyExternalStorage()
                             && smInternal.hasLegacyExternalStorage(appInfo.uid);
                     targetSDK = getMinimumTargetSDK(context, appInfo, user);
+                    // LEGACY_STORAGE op is normally sticky for apps targetig <= Q.
+                    // However, this device can be configured to make it non-sticky.
+                    boolean isLegacyAppOpSticky = isLegacyStorageAppOpStickyGlobal
+                            && targetSDK <= Build.VERSION_CODES.Q;
                     shouldApplyRestriction = (flags & FLAG_PERMISSION_APPLY_RESTRICTION) != 0
-                            || (targetSDK > Build.VERSION_CODES.Q
-                            && !shouldPreserveLegacyExternalStorage);
+                            || (!isLegacyAppOpSticky && !shouldPreserveLegacyExternalStorage);
                 } else {
                     isWhiteListed = false;
                     shouldApplyRestriction = false;