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Script to search offset of the LUKS header on a device file
#!/usr/bin/env python3
import threading
import queue
import argparse
import os.path
import sys
NUM_WORKER_THREADS = 16
LUKS_HEADER = b'LUKS\xba\xbe'
BLOCK_SIZE = 1024
# globals
q = queue.Queue()
found = False
def look_for_header(item):
global found
f, offset = item
f.seek(offset)
b = f.read(BLOCK_SIZE)
indx = b.find(LUKS_HEADER)
if indx != -1:
found = True
print(f'Found LUKS header at offset {offset+indx} (in bytes)')
def worker():
global q
while True:
item = q.get()
if not found:
look_for_header(item)
q.task_done()
def main(args):
for i in range(NUM_WORKER_THREADS):
t = threading.Thread(target=worker)
t.daemon = True
t.start()
for offset in range(0, args.limit*1024*1024, BLOCK_SIZE):
item = (args.f, offset)
q.put(item)
q.join() # block until all tasks are done
if __name__ == '__main__':
parser = argparse.ArgumentParser(description='Look for LUKS header in device file')
parser.add_argument('-l', '--limit', default=2, type=int, help='limit in MB where to look for the header (default=2)')
parser.add_argument('device', help='the device where to look for LUKS header')
args = parser.parse_args()
if not os.path.isfile(args.device):
print(f'Error: device {args.device} not found or not readable', file=sys.stderr)
sys.exit(-1)
try:
args.f = open(args.device, 'rb')
main(args)
args.f.close()
except KeyboardInterrupt as k:
print('Aborted by user')
finally:
args.f.close()
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