PigPEI is a simple UEFI bootkit which can intercept DxeMain by running as PEIM
during the PEI phase. As a consequence, PigPEI is able to fully control DxeMain
initialisation and later stages of boot. The Python FFS injector does not work
with the current build of PigPEI because FFS relocations were too tedious to
implement so you will need to use UEFITool to inject PigPEI into firmware.

PigPEI does not do anything exciting. The bootkit installs a single persistent
hook to write to UART when ExitBootServices() is called.  However, it is very
straightforward to add additional hooks to manipulate the OS (e.g. intercepting
GetVariable attempting to read SecureBoot) or privileged DXE modules in SMRAM.

PigPEI is limited to OvmfPkg so it will not work out of the box for real
firmware images. If you want to make it work on real devices then you are free
to modify the old FFS injector and play around with the code.

There are two ways to setup PigPEI:
1) Download the files in the GitHub releases tab, extract at repository root.
2) First, compile OVMF from EDK-2 then put the compiled files in ./fv. Then
    build PigPEI with 'cargo build' before building an FFS file using
    ./toolchain/prepare_ffs_file.py. Finally use UEFITool to manually insert.

Dependencies:
- Rust
- QEMU
- Python (optional)
- UEFITool (optional)

To build and run PigPEI in an emulator:
$ ./run.sh
...
[OK] loaded PigPEI
[??] hooking InstallPpi in EFI_PEI_SERVICES
[OK] trapped DxeLoadCore before DxeCore is called
[??] searching for d6a2cb7f-6a18-4e2f-b43b-9920a733700a HOB
[OK] found DxeCore HOB at 0x1bf58d48
[??] scanning address range 0x1fe89000-0x1feb7000
[OK] found EFI_SYSTEM_TABLE at 0x1feaee00
[OK] found EFI_BOOT_SERVICES at 0x1feae820
[OK] found EFI_RUNTIME_SERVICES at 0x1feadd80
[??] verifying table contents are as expected
[??] gRT->GetTime       = 0x1fe98c72
[??] gRT->SetTime       = 0x1fe98c67
[??] gRT->SetWakeupTime = 0x1fe98c72
[OK] table contents have been successfully validated
[OK] hooking gBS->RegisterProtocolNotify
[OK] intercepted DxeMain after initialisation
[??] searching pages for table signatures
[??] cr3 = 1fc01000
[??] PML4 = 0x1fc01000
[OK] found EFI_SYSTEM_TABLE at 0x1f9ee018
[OK] found EFI_RUNTIME_SERVICES at 0x1f9eeb98
[OK] found referential pair of UEFI tables, all tables found
[??] gST                  = 0x1f9ee018
[??] gST->RuntimeServices = 0x1f9eeb98
[??] gST->BootServices    = 0x1feae820
[OK] installing gBS->ExitBootServices hook
[OK] removing gBS->RegisterProtocolNotify hook