[python] support cromfs extraction

This commit is contained in:
nganhkhoa 2024-09-19 09:32:02 +07:00
parent 558deed4c8
commit ad4857317f
4 changed files with 66 additions and 25 deletions

View File

@ -2,6 +2,8 @@ import argparse
import os
import io
from pathlib import Path
import matcher
signatures = [
@ -28,13 +30,22 @@ def detect(args):
print("detected", filetype.name)
for m in filetype.matches:
print(">", m)
filetype.view(m)
filetype.view(m, None)
return matches
def extract(args):
pass
file = Path(args.file)
folder = file.parent / (file.name + "_extracted")
folder.mkdir(exist_ok=True)
matches = detect(args)
for filetype in matches:
print("detected", filetype.name)
for m in filetype.matches:
print(">", m)
filetype.view(m, folder)
def main():
parser = argparse.ArgumentParser(description='Program for detecting or extracting data.')
@ -68,19 +79,8 @@ def main():
if args.command == 'detect':
detect(args)
# if args.isa:
# # Perform ISA detection on the file
# print('Performing ISA detection on:', args.file)
# else:
# parser.print_help()
elif args.command == 'extract':
extract(args)
# if args.dry:
# # Perform a dry run without extracting
# print('Dry run extraction from:', args.file)
# else:
# # Extract data from the file
# print('Extracting data from:', args.file)
else:
parser.print_help()

View File

@ -1,6 +1,10 @@
import os
import io
from pathlib import Path
import lzf
from .matcher import SignatureMatcher, Match
class CromFS(SignatureMatcher):
@ -50,7 +54,19 @@ class CromFS(SignatureMatcher):
return len(self.matches) != 0
def view(self, match):
def view(self, match, root_folder):
def extract(path, is_folder):
if root_folder is None:
return
p = root_folder / ('_' + hex(match.offset))
p.mkdir(exist_ok=True)
p = p / path
if is_folder:
p.mkdir(exist_ok=True)
else:
p.touch(exist_ok=True)
return open(p, 'wb')
as_num = lambda x: int.from_bytes(x, 'little')
root = match.data['root']
@ -77,6 +93,31 @@ class CromFS(SignatureMatcher):
buffer.seek(old, os.SEEK_SET)
return s.decode()
def read_file_contents(buffer, at=None, recover=False, file=None, total_size=0):
old = buffer.tell()
if at:
buffer.seek(at, os.SEEK_SET)
file_contents = b''
while total_size > 0:
magic = buffer.read(2)
typ = as_num(buffer.read(1))
if typ == 0:
len = as_num(buffer.read(1)) << 8 | as_num(buffer.read(1))
uncompress = buffer.read(len)
file_contents += uncompress
total_size -= len
if typ == 1:
clen = as_num(buffer.read(1)) << 8 | as_num(buffer.read(1))
ulen = as_num(buffer.read(1)) << 8 | as_num(buffer.read(1))
compressed = buffer.read(clen)
file_contents += lzf.decompress(compressed, ulen)
total_size -= ulen
if file:
file.write(file_contents)
if recover:
buffer.seek(old, os.SEEK_SET)
def read_nodes(buffer, current):
mode = as_num(buffer.read(2))
buffer.read(2)
@ -89,23 +130,24 @@ class CromFS(SignatureMatcher):
is_reg = lambda mode: mode & (8 << 12) != 0
is_link = lambda mode: mode & (10 << 12) != 0
path = current + '/' + name
print(path)
path = current / name
if is_link(mode):
pass
if is_dir(mode):
extract(path, True)
# traverse the directory children
buffer.seek(extra, os.SEEK_SET)
read_nodes(buffer, current + '/' + name)
if is_reg(mode):
for block in range(extra):
# decrypt each block
pass
read_nodes(buffer, path)
if is_reg(mode) and name != '.' and name != '..':
f = extract(path, False)
read_file_contents(buffer, at=extra, recover=True, total_size=size, file=f)
if f:
f.close()
# traverse its peer
if peer != 0:
buffer.seek(peer, os.SEEK_SET)
read_nodes(buffer, current)
read_nodes(region, '')
read_nodes(region, Path(''))

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@ -27,5 +27,5 @@ class SignatureMatcher:
def is_valid(self):
return False
def view(self, match):
def view(self, match, root_folder=None):
pass

View File

@ -27,8 +27,7 @@ class RomFS(SignatureMatcher):
return len(self.matches) != 0
def view(self, match):
def view(self, match, root_folder):
start = match.offset
length = match.length
raw = io.BytesIO(self.file[start:start+length])