Q Preview 1 compatiblity

Chainfire · Chainfire · commit e7ea8c2fe242 · 2019-03-21T17:57:21.000+01:00
On several older Android versions we needed to relocate app_process to prevent it from being executed in a restricted SELinux context, but this causes the "Error finding namespace of apex: no namespace called runtime" linker error on Q Preview 1. Running app_process straight from /system/bin (and daemonizer from /data/.../lib) works fine however on QP1, so we just skip relocating altogher for now. Closes Chainfire#4
diff --git a/librootjava/src/main/java/eu/chainfire/librootjava/AppProcess.java b/librootjava/src/main/java/eu/chainfire/librootjava/AppProcess.java
@@ -283,13 +283,37 @@ public static boolean guessIfAppProcessIs64Bits(String app_process) {
         return !isRunningAs32BitOn64BitArch();
     }
 
+    /**
+     * Should app_process be relocated ?<br>
+     * <br>
+     * On older Android versions we must relocate the app_process binary to prevent it from
+     * running in a restricted SELinux context. On Q this presents us with the linker error:
+     * "<i>Error finding namespace of apex: no namespace called runtime</i>". However, at least
+     * on the first preview release of Q, running straight from /system/bin works and does
+     * <i>not</i> give us a restricted SELinux context, so we skip relocation.
+     *
+     * TODO: Revisit on new Q preview and production releases. Maybe spend some time figuring out what causes the namespace error and if we can fix it.
+     *
+     * @see #getAppProcessRelocate(Context, String, List, List, String)
+     *
+     * @return should app_process be relocated ?
+     */
+    @TargetApi(Build.VERSION_CODES.M)
+    public static boolean shouldAppProcessBeRelocated() {
+        return !(
+            (Build.VERSION.SDK_INT >= 29) ||
+            ((Build.VERSION.SDK_INT == 28) && (Build.VERSION.PREVIEW_SDK_INT != 0))
+        );
+    }
+
     /**
      * Create script to relocate specified app_process binary to a different location.<br>
      * <br>
      * On many Android versions and roots, executing app_process directly will force an
      * SELinux context that we do not want. Relocating it bypasses that.<br>
      *
      * @see #getAppProcess()
+     * @see #shouldAppProcessBeRelocated()
      *
      * @param context Application or activity context
      * @param appProcessBase Path to original app_process or null for default
@@ -301,6 +325,10 @@ public static boolean guessIfAppProcessIs64Bits(String app_process) {
     public static String getAppProcessRelocate(Context context, String appProcessBase, List<String> preLaunch, List<String> postExecution, String path) {
         if (appProcessBase == null) appProcessBase = getAppProcess();
         if (path == null) {
+            if (!shouldAppProcessBeRelocated()) {
+                return appProcessBase;
+            }
+
             path = "/dev";
             if ((context.getApplicationInfo().flags & ApplicationInfo.FLAG_EXTERNAL_STORAGE) == 0) {
                 File cacheDir = context.getCacheDir();
diff --git a/librootjavadaemon/src/main/java/eu/chainfire/librootjavadaemon/RootDaemon.java b/librootjavadaemon/src/main/java/eu/chainfire/librootjavadaemon/RootDaemon.java
@@ -73,18 +73,27 @@ public static List<String> patchLaunchScript(Context context, List<String> scrip
                 // patch the main script line
                 String app_process_path = app_process.substring(0, app_process.lastIndexOf('/'));
 
-                // copy our executable
-                String libSrc = RootJava.getLibraryPath(context, "daemonize");
-                String libDest = app_process_path + "/.daemonize_" + AppProcess.UUID;
-                boolean onData = libDest.startsWith("/data/");
+                // our executable
+                String libSource = RootJava.getLibraryPath(context, "daemonize");
+                String libExec;
+
+                if (app_process_path.startsWith("/system/bin")) {
+                    // app_process was not relocated, assume caller knows what he's doing, and
+                    // run our executable from its library location
+                    libExec = libSource;
+                } else {
+                    // copy our executable
+                    libExec = app_process_path + "/.daemonize_" + AppProcess.UUID;
+                    boolean onData = libExec.startsWith("/data/");
 
-                ret.add(String.format(Locale.ENGLISH, "%s cp %s %s >/dev/null 2>/dev/null", AppProcess.BOX, libSrc, libDest));
-                ret.add(String.format(Locale.ENGLISH, "%s chmod %s %s >/dev/null 2>/dev/null", AppProcess.BOX, onData ? "0766" : "0700", libDest));
-                if (onData) ret.add(String.format(Locale.ENGLISH, "restorecon %s >/dev/null 2>/dev/null", libDest));
+                    ret.add(String.format(Locale.ENGLISH, "%s cp %s %s >/dev/null 2>/dev/null", AppProcess.BOX, libSource, libExec));
+                    ret.add(String.format(Locale.ENGLISH, "%s chmod %s %s >/dev/null 2>/dev/null", AppProcess.BOX, onData ? "0766" : "0700", libExec));
+                    if (onData) ret.add(String.format(Locale.ENGLISH, "restorecon %s >/dev/null 2>/dev/null", libExec));
+                }
 
                 // inject executable into command
                 int idx = line.indexOf(app_process);
-                ret.add(line.substring(0, idx) + libDest + " " + line.substring(idx));
+                ret.add(line.substring(0, idx) + libExec + " " + line.substring(idx));
 
                 in_post = true;
             } else if (in_post && line.contains("box rm")) {
