adb - How can run native executables compiled for ARM on unrooted Android devices?

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Closed 10 months ago.

Following this tutorial I have compiled a Hello World! ARM binary from C source using gcc. I want to run this program on my unrooted Android phone but I can't figure out an easy way to do it.

What I've tried:

1. 
   

   Copying hello to /sdcard and trying to run it from there. This doesn't work because the internal storage is mounted with the noexec flag.

   
   


2. 
   

   Copying hello to /data/local/ using cp hello /data/local/ or cat hello > /data/local/hello as explained here. This also doesn't work and I get a "permission denied" error.

   
   


3. 
   
   

   Installing a terminal emulator program such as Termux and using the Termux app to copy hello from /sdcard/hello to /data/data/com.termux/files/home, running chmod +x hello and then running ./hello from the Termux home directory within the Termux app. This works but is not a feasible solution.

   
   

Is there a better/easier way to run native ELF executables on an unrooted Android phone directly through ADB and doesn't involve installing any apps?

Answer

1. In addition to noexec mount option, /sdcard is emulated filesystem with fixed file permissions. So files can't be set executable. But some file explorers like MiXplorer support executing binaries/scripts from /sdcard through /system/bin/sh.


2. /data/local has permissions 0751, owner root.root ¹, so normal apps can't access it. However from adb shell use /data/local/tmp which has user/group owner 2000 (aid_shell) ² and selinux is also allowed ³. So you won't get permission denied.


3. If you don't want to use PC, terminal emulator is the only option. On Termux you can also add /data/local/tmp (or a subdirectory) to $PATH by editing ~/.profile if you want to avoid placing binaries on multiple locations. But the directory should be world-readable and selinux must not be denying the access or execution of binaries.