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| -rwxr-xr-x | util/tpm_hash_gen.py | 114 |
1 files changed, 0 insertions, 114 deletions
diff --git a/util/tpm_hash_gen.py b/util/tpm_hash_gen.py deleted file mode 100755 index bf1c661cf2..0000000000 --- a/util/tpm_hash_gen.py +++ /dev/null @@ -1,114 +0,0 @@ -#!/usr/bin/python -# Copyright 2020 The ChromiumOS Authors -# Use of this source code is governed by a BSD-style license that can be -# found in the LICENSE file. -"""A program for calculating Cr50 TPM image identifier used in UMA. - -The code of this program is a Python equivalent of the code of function -GetFingerprint() defined in - -https://chromium.googlesource.com/chromiumos/platform2/+/16911186/cryptohome/tpm.cc#78 - -""" - -import hashlib -import re -import sys - -class MyError(Exception): - """Local Exception wrapper.""" - pass - - -def get_git_versions(cr50_file): - """Find git versions in a Cr50 binary image. - - The Cr50 version string is generated at build time by the - ./util/getversion.sh script. The version string is built based on the - following template: - - cr50_v<vers>-<git sha> tpm2:<vers>-<git sha> ... <year>-<month>-<day> - - Since the Cr50 image includes sections for RW_A and RW_B, the same version - string is supposed to be present in the image twice. - - This function reads the passed in file name, looks for the version, makes - sure that the version is present twice and both instances are identical, - then extracts git hashes of the ec and tpm2 trees from the version string - and returns them as a list of two integers. - - Args: - cr50_file: A string, name of the Cr50 image file. - - Returns: - A list of two integers, hashes of ec and tpm2 trees at build time. - - Raises: - MyError: if consistent version string was not found in the file. - - """ - git_vers_regexp = re.compile(b'cr50_v[1-4].* tpm2.* 20[12][0-9]') - text = open(cr50_file, 'rb').read() - strings = git_vers_regexp.findall(text) - hashes = [] - - if len(strings) != 2 or strings[0] != strings[1]: - raise MyError('Could not find git version string in %s' % cr50_file) - - for piece in strings[0].decode().split(): - if piece.startswith('cr50_') or piece.startswith('tpm2'): - hashes.append(piece.split('-')[1]) - - return [int(x, 16) for x in hashes] - - -def hash_cr50_file(cr50_file): - """Calculate UMA key of a Cr50 image. - - Find out git hashes of the ec and tpm2 components of the passed in Cr50 - image and then generate a file hash following the same pattern which is - used by - https://chromium.googlesource.com/chromiumos/platform2/+/16911186/cryptohome/tpm.cc#78 - - Args: - cr50_file: A string, name of the Cr50 image file. - - Returns: - An int, cr50 image hash calculated following the fixed template. - """ - git_versions = get_git_versions(cr50_file) - hash_const = '322e3000000000000000007443524f5300000001' - tpm_hash_template = '%s%8.8x%8.8x%16.16x%s' - vendor_specific = 'xCG fTPM' - - hash_input = tpm_hash_template % (hash_const, git_versions[0], - git_versions[1], len(vendor_specific), - vendor_specific) - - h = hashlib.sha256() - h.update(bytes(hash_input, 'ascii')) - - hex_digest = h.hexdigest() - uma_digest_list = [hex_digest[2*x:2*x + 2] for x in range(4)] - hex_uma_key = ''.join(uma_digest_list[::-1]) - uma_key = int(hex_uma_key, 16) & 0x7fffffff - return uma_key - - -def main(cr50_files): - """Calculate and report UMA keys for passed in Cr50 images. - - Args: - cr50_files: A list of strings, names of Cr50 files to hash. - """ - for cr50_file in cr50_files: - key = hash_cr50_file(cr50_file) - print('%08x %-9d %s' % (key, key, cr50_file)) - -if __name__ == '__main__': - try: - main(sys.argv[1:]) - except MyError as e: - print('Error:', e) - sys.exit(1) - sys.exit(0) |