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196 | import argparse
import os
from ofrak_patch_maker.toolchain.llvm_12 import LLVM_12_0_1_Toolchain
import ofrak_ghidra
from ofrak import OFRAK, OFRAKContext, Resource, ResourceFilter, ResourceAttributeValueFilter
from ofrak.core import (
Allocatable,
CodeRegion,
ComplexBlock,
Instruction,
LiefAddSegmentConfig,
LiefAddSegmentModifier,
ElfProgramHeader,
)
from ofrak.core.patch_maker.modifiers import (
PatchFromSourceModifier,
PatchFromSourceModifierConfig,
SourceBundle,
)
from ofrak_patch_maker.toolchain.model import (
ToolchainConfig,
BinFileType,
CompilerOptimizationLevel,
Segment,
)
from ofrak_patch_maker.toolchain.utils import get_file_format
from ofrak_type import Range
from ofrak_type.memory_permissions import MemoryPermissions
ASSETS_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__), "assets"))
BINARY_FILE = os.path.join(ASSETS_DIR, "example_program")
PAGE_ALIGN = 0x1000
GHIDRA_PIE_OFFSET = 0x100000 # Ghidra bases PIE executables at 0x100000
async def add_and_return_segment(elf_resource: Resource, vaddr: int, size: int) -> ElfProgramHeader:
"""Add a segment to `elf_resource`, of size `size` at virtual address `vaddr`,
returning this new segment resource after unpacking."""
config = LiefAddSegmentConfig(vaddr, PAGE_ALIGN, [0 for _ in range(size)], "rx")
await elf_resource.run(LiefAddSegmentModifier, config)
await elf_resource.unpack_recursively()
# Get our newly added segment. First get all ElfProgramHeaders, then return the one
# with our virtual address.
file_segments = await elf_resource.get_descendants_as_view(
ElfProgramHeader, r_filter=ResourceFilter(tags=(ElfProgramHeader,))
)
segment = [seg for seg in file_segments if seg.p_vaddr == vaddr].pop()
# Carve out a child of the new segment where we can store the code for our new function.
code_region = CodeRegion(segment.p_vaddr + GHIDRA_PIE_OFFSET, segment.p_filesz)
code_region.resource = await elf_resource.create_child_from_view(
code_region, data_range=Range(segment.p_offset, segment.p_offset + segment.p_filesz)
)
elf_resource.add_tag(Allocatable)
await elf_resource.save()
return segment
async def call_new_segment_instead(resource: Resource, new_segment: ElfProgramHeader):
"""Replace the original `call` instruction in main with a call to the start of `new_segment`."""
main_cb = await resource.get_only_descendant_as_view(
v_type=ComplexBlock,
r_filter=ResourceFilter(
attribute_filters=(ResourceAttributeValueFilter(ComplexBlock.Symbol, "main"),)
),
)
call_instruction = await main_cb.resource.get_only_descendant_as_view(
v_type=Instruction,
r_filter=ResourceFilter(
attribute_filters=(ResourceAttributeValueFilter(Instruction.Mnemonic, "call"),)
),
)
ghidra_new_segment_vaddr = new_segment.p_vaddr + GHIDRA_PIE_OFFSET
await call_instruction.modify_assembly("call", f"0x{ghidra_new_segment_vaddr:x}")
async def patch_uppercase(resource: Resource, source_dir: str, new_segment: ElfProgramHeader):
# The PatchMaker will need to know how to configure the build toolchain.
tc_config = ToolchainConfig(
file_format=BinFileType.ELF,
force_inlines=True,
relocatable=True,
no_std_lib=True,
no_jump_tables=True,
no_bss_section=True,
create_map_files=True,
compiler_optimization_level=CompilerOptimizationLevel.SPACE,
debug_info=False,
check_overlap=False,
)
# Tell the PatchMaker about the segment we added in the binary...
text_segment_uppercase = Segment(
segment_name=".text",
vm_address=new_segment.p_vaddr + GHIDRA_PIE_OFFSET,
offset=0,
is_entry=False,
length=new_segment.p_filesz,
access_perms=MemoryPermissions.RX,
)
# ... And that we want to put the compiled C patch there.
uppercase_source: str = os.path.join(source_dir, "uppercase.c")
segment_dict = {
uppercase_source: (text_segment_uppercase,),
}
# Tell PatcherFromSourceModifier about the source files, toolchain, and patch name.
patch_from_source_config = PatchFromSourceModifierConfig(
SourceBundle.slurp(source_dir),
segment_dict,
tc_config,
LLVM_12_0_1_Toolchain,
patch_name="HELLO_WORLD",
)
# Run PatchFromSourceModifier, which will analyze the target binary, run PatchMaker on our
# patch, create a Batch of Objects and Metadata (BOM) for the patch, create a BOM from the
# target binary for all unresolved symbols in the patch, make a Final Executable and Metadata
# (FEM), and then inject our patch into the binary.
await resource.run(PatchFromSourceModifier, patch_from_source_config)
async def main(ofrak_context: OFRAKContext, file_path: str, output_file_name: str):
try:
root_resource = await ofrak_context.create_root_resource_from_file(file_path)
except FileNotFoundError:
raise RuntimeError(
f"Cannot find the file {file_path}. Did you run the Makefile to build it?"
)
new_segment = await add_and_return_segment(root_resource, 0x108000, 0x2000)
source_dir = os.path.abspath(os.path.join(os.path.dirname(__file__), "src", "example_7"))
await patch_uppercase(root_resource, source_dir, new_segment)
await call_new_segment_instead(root_resource, new_segment)
await root_resource.pack()
await root_resource.flush_data_to_disk(output_file_name)
assert os.path.exists(output_file_name)
assert get_file_format(output_file_name) == BinFileType.ELF
print(f"Done! Output file written to {output_file_name}")
if __name__ == "__main__":
parser = argparse.ArgumentParser()
parser.add_argument("--hello-world-file", default=BINARY_FILE)
parser.add_argument("--output-file-name", default="./example_7_uppercase")
args = parser.parse_args()
ofrak = OFRAK()
ofrak.discover(ofrak_ghidra)
ofrak.run(main, args.hello_world_file, args.output_file_name)
|
