permission is denied using Android Q ffmpeg": error=13, Permission denied

Question

I want to get the frames from the RTSP video using ffmpeg. But for android 10 above I am getting error as below.

 E/FFmpeg: Exception while trying to run: [Ljava.lang.String;@55e447f
java.io.IOException: Cannot run program "/data/user/0/com.example.downloadimagefromurl/files/ffmpeg": error=13, Permission denied
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1050)
    at java.lang.Runtime.exec(Runtime.java:698)
    at java.lang.Runtime.exec(Runtime.java:563)
    at com.github.hiteshsondhi88.libffmpeg.ShellCommand.run(ShellCommand.java:10)
    at com.github.hiteshsondhi88.libffmpeg.FFmpegExecuteAsyncTask.doInBackground(FFmpegExecuteAsyncTask.java:38)
    at com.github.hiteshsondhi88.libffmpeg.FFmpegExecuteAsyncTask.doInBackground(FFmpegExecuteAsyncTask.java:10)
    at android.os.AsyncTask$3.call(AsyncTask.java:378)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:289)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
    at java.lang.Thread.run(Thread.java:919)
 Caused by: java.io.IOException: error=13, Permission denied
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:133)

As the answer provided by @Saurabh Thorat, Google doesn't allow apps to run binary files from /data/user directory.

One bad solution that I know is to change compileSdkVersion and targetSdkVersion to 28 or below and re-release my application which is not recommended.

Hence, I am looking for more viable solutions for future releases as well.

Any hint, links or suggestion would be highly appreciated. Thanks in advance.

Answer 1

From Android Q onwards, you cannot execute binaries in your app's private data directory.

From the issuetracker: https://issuetracker.google.com/issues/128554619

The change to block exec() on application data files for targetAPI >= Q is working-as-intended. Please see https://android-review.googlesource.com/c/platform/system/sepolicy/+/804149 for background on this change. Calling exec() on writable application files is a W^X (https://en.wikipedia.org/wiki/W%5EX) violation and represents an unsafe application practice. Executable code should always be loaded from the application APK.

While exec() no longer works on files within the application home directory, it continues to be supported for files within the read-only /data/app directory. In particular, it should be possible to package the binaries into your application's native libs directory and enable android:extractNativeLibs=true, and then call exec() on the /data/app artifacts. A similar approach is done with the wrap.sh functionality, documented at https://developer.android.com/ndk/guides/wrap-script#packaging_wrapsh .

Additionally, please be aware that executables executed via exec() are not managed according to the Android process lifecycle, and generally speaking, exec() is discouraged from Android applications. While not Android documentation, Using "exec()" with NDK covers this in some detail. Relying on exec() may be problematic in future Android versions.