PongoOS : A Pre-Boot Execution Environment For Apple Boards

PongoOS is a pre-boot execution environment for Apple boards built on top of checkra1n.

Building On macOS

• Install Xcode + command-line utilities
• Run make all

Building On Linux

• Install clang (if in doubt, from apt.llvm.org)
• Install ld64 and cctools’ strip.
  • On Debian/Ubuntu these can be installed from the checkra1n repo:

echo ‘deb https://assets.checkra.in/debian /’ | sudo tee /etc/apt/sources.list.d/checkra1n.list
sudo apt-key adv –fetch-keys https://assets.checkra.in/debian/archive.key
sudo apt-get update
sudo apt-get install -y ld64 cctools-strip

• On other Linux flavours you’ll likely have to build them yourself. Maybe this repo will help you.

If clang, ld64 or cctools-strip don’t have their default names/paths, you’ll want to change their invocation. For reference, the default variables are equivalent to:

EMBEDDED_CC=clang EMBEDDED_LDFLAGS=-fuse-ld=/usr/bin/ld64 STRIP=cctools-strip make all

Build Artifacts

The Makefile will create four binaries in build/:

• Pongo – A Mach-O of the main PongoOS
• Pongo.bin – Same as the above, but as a bare metal binary that can be jumped to
• checkra1n-kpf-pongo – The checkra1n kernel patchfinder, as a Pongo module (Mach-O/kext)
• PongoConsolidated.bin – PongoOS and the KPF merged into a single binary

Usage

checkra1n -k Pongo.bin                  # Boots to Pongo shell, KPF not available
checkra1n -k PongoConsolidated.bin      # Auto-runs KPF and boots to XNU
checkra1n -k PongoConsolidated.bin -p   # Loads KPF, but boots to Pongo shell

Structure

• The core PongoOS and drivers are in src/.
  • Build-time helper tools are in tools/.
• The stdlib used by PongoOS (Newlib) is in aarch64-none-darwin.
  • This includes a custom patch for Newlib to work with the Darwin ABI.
• An example module exists in example/.
• Scripts to communicate with the PongoOS shell are in scripts/.
  • This includes pongoterm, an interactive shell client for macOS.
• The checkra1n kernel patchfinder (KPF) is in checkra1n/kpf.
  • This currently includes the SEP exploit, though that is to be moved into mainline PongoOS in the future.
• A userland version of the KPF can be built from checkra1n/kpf-test (can only be run on arm64).