Awesome

Android/Linux vmlinux loader

vmlinux.py is a python script which can load vmlinux image in both IDA Pro and radare2.

vmlinux

vmlinux is a decompressed kernel image, personally I prefer to extract it from boot.img by binwalk. However, imgtool is another good choice.

./imgtool pixel_boot.img extract
lz4 -d extracted/kernel ./pixel_vmlinux

is this file a valid vmlinux image?

Droidimg is designed for modern Linux kernels on Android devices. Since then, it support 3.4+ kernel in arm or arm64 architecture. To quickly determine if you have a valid vmlinux image:

Try strings and grep:

strings vmlinux | grep "Linux version "

If there is no output like this linux banner string, then you don't have a valid vmlinux file. Extracting vmlinux can be complex on some devices, search XDA for guidance.

Linux version 4.9.17-g8ab68b3b (ubuntu@A7Linux) (gcc version 4.9.x 20150123 (prerelease) (GCC) ) #1 SMP PREEMPT Sat Jan 12 15:51:20 CST 2019

If the script failed to determine the architecture, most likely the architecture is unsupported.
Some boot image with UNCOMPRESSED kernel has a 20 bytes header in front of kernel text. Strip it and try again.

usage

IDA Pro

vmlinux.py		->		C:\Program Files\IDA x.x\loaders\

radare2

r2 -i ./vmlinux.py ./test/pixel_vmlinux

Command Line

python ./vmlinux.py ./test/pixel_vmlinux

Use -j/--json to produce json output, which can be consumed by other components

Use -m/--miasm to enable miasm simulation engine in case some symbols are not exported (experimental). Note that only Python 2 is supported by miasm for now.

Miasm: https://github.com/cea-sec/miasm

KASLR

In some cases, kernel image with KASLR enabled will populate relocation entries upon boot and leave them as 0 in image. fix_kaslr_arm64.c and fix_kaslr_samsung.c can fix these images by re-populating relocation entries with their original addresses.