Update preference migration implementation

Only try to read preference through content provider when the app
is fresh install and a previous package ID is set. Also catch all
Exceptions to prevent crashing the app.

This prevents malicious settings injection and crashes when multiple
manager is installed.

Fix #3542

app/src/main/AndroidManifest.xml

@@ -12,7 +12,7 @@
     <application
         android:icon="@drawable/ic_launcher"
         android:name="a.e"
-        android:allowBackup="true"
+        android:allowBackup="false"
         tools:ignore="UnusedAttribute,GoogleAppIndexingWarning">
 
         <!-- Splash -->

app/src/main/java/com/topjohnwu/magisk/core/Config.kt

@@ -18,7 +18,6 @@ import com.topjohnwu.magisk.ktx.inject
 import com.topjohnwu.magisk.ui.theme.Theme
 import org.xmlpull.v1.XmlPullParser
 import java.io.File
-import java.io.IOException
 import java.io.InputStream
 
 object Config : PreferenceModel, DBConfig {
@@ -159,12 +158,13 @@ object Config : PreferenceModel, DBConfig {
 
     private const val SU_FINGERPRINT = "su_fingerprint"
 
-    fun load(pkg: String) {
+    fun load(pkg: String?) {
-        try {
+        // Only try to load prefs when fresh install and a previous package name is set
+        if (pkg != null && prefs.all.isEmpty()) runCatching {
             context.contentResolver.openInputStream(Provider.PREFS_URI(pkg))?.use {
                 prefs.edit { parsePrefs(it) }
             }
-        } catch (e: IOException) {}
+        }
 
         prefs.edit {
             // Settings migration

app/src/main/java/com/topjohnwu/magisk/core/Const.kt

@@ -58,7 +58,7 @@ object Const {
     object Key {
         // intents
         const val OPEN_SECTION = "section"
-        const val HIDDEN_PKG = "hidden_pkg"
+        const val PREV_PKG = "prev_pkg"
     }
 
     object Value {

app/src/main/java/com/topjohnwu/magisk/core/SplashActivity.kt

@@ -48,10 +48,10 @@ open class SplashActivity : Activity() {
         // Pre-initialize root shell
         Shell.getShell()
 
-        val hiddenPackage = intent.getStringExtra(Const.Key.HIDDEN_PKG)
+        val prevPkg = intent.getStringExtra(Const.Key.PREV_PKG)
 
-        Config.load(hiddenPackage ?: APPLICATION_ID)
+        Config.load(prevPkg)
-        handleRepackage(hiddenPackage)
+        handleRepackage(prevPkg)
         Notifications.setup(this)
         UpdateCheckService.schedule(this)
         Shortcuts.setupDynamic(this)

app/src/main/java/com/topjohnwu/magisk/core/tasks/HideAPK.kt

@@ -123,6 +123,7 @@ object HideAPK {
             Config.suManager = pkg
             grantUriPermission(pkg, APK_URI, Intent.FLAG_GRANT_READ_URI_PERMISSION)
             grantUriPermission(pkg, PREFS_URI, Intent.FLAG_GRANT_READ_URI_PERMISSION)
+            intent.putExtra(Const.Key.PREV_PKG, packageName)
             startActivity(intent)
         }
 
@@ -167,7 +168,7 @@ object HideAPK {
             Config.suManager = ""
             grantUriPermission(APPLICATION_ID, APK_URI, Intent.FLAG_GRANT_READ_URI_PERMISSION)
             grantUriPermission(APPLICATION_ID, PREFS_URI, Intent.FLAG_GRANT_READ_URI_PERMISSION)
-            intent.putExtra(Const.Key.HIDDEN_PKG, packageName)
+            intent.putExtra(Const.Key.PREV_PKG, packageName)
             startActivity(intent)
         }