tor-browser-build/projects/browser/pe_checksum_fix.py

#!/usr/bin/env python3

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"""
NSIS is neither padding nor calculating the PE-file checksum. But the tool
we use for signing and the tools for stripping the signature do which leads to a
SHA256 mismatch if one tries to check that the binary we offer is actually the
the one we got from our reproducible builds.

This small Python snippet does both things: It pads the .exe if necessary and it
recalculates the PE-file checksum. Details of the discussion can be found in bug
15339: https://bugs.torproject.org/15539.

Thanks to a cypherpunk for this workaround idea.
"""

import pefile;

f = open('browser-install-tmp.exe', 'rb')
exe = f.read()
f.close()
remainder = len(exe) % 8
if remainder > 0:
    exe += bytes('\0' * (8 - remainder), 'utf-8')
pef = pefile.PE(data=exe, fast_load=True)
pef.OPTIONAL_HEADER.CheckSum = pef.generate_checksum()
pef.write(filename='browser-install-tmp2.exe')