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112 lines
4.2 KiB
112 lines
4.2 KiB
#! /usr/bin/env python |
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# |
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# Copyright (C) 2013 The Android Open Source Project |
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# |
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# Licensed under the Apache License, Version 2.0 (the "License"); |
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# you may not use this file except in compliance with the License. |
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# You may obtain a copy of the License at |
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# |
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# http://www.apache.org/licenses/LICENSE-2.0 |
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# |
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# Unless required by applicable law or agreed to in writing, software |
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# distributed under the License is distributed on an "AS IS" BASIS, |
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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# See the License for the specific language governing permissions and |
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# limitations under the License. |
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import argparse |
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import os |
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import sys |
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import struct |
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import shlex |
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import subprocess |
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import tempfile |
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VERSION = 0 |
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MAGIC_NUMBER = 0xb001b001 |
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BLOCK_SIZE = 4096 |
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METADATA_SIZE = BLOCK_SIZE * 8 |
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def run(cmd): |
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p = subprocess.Popen(cmd, stdout=subprocess.PIPE) |
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output, _ = p.communicate() |
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print output |
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if p.returncode: |
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exit(-1) |
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def get_verity_metadata_size(data_size): |
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return METADATA_SIZE |
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def build_metadata_block(verity_table, signature): |
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table_len = len(verity_table) |
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block = struct.pack("II256sI", MAGIC_NUMBER, VERSION, signature, table_len) |
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block += verity_table |
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block = block.ljust(METADATA_SIZE, '\x00') |
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return block |
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def sign_verity_table(table, signer_path, key_path, signer_args=None): |
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with tempfile.NamedTemporaryFile(suffix='.table') as table_file: |
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with tempfile.NamedTemporaryFile(suffix='.sig') as signature_file: |
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table_file.write(table) |
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table_file.flush() |
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if signer_args is None: |
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cmd = [signer_path, table_file.name, key_path, signature_file.name] |
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else: |
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args_list = shlex.split(signer_args) |
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cmd = [signer_path] + args_list + [table_file.name, key_path, signature_file.name] |
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print cmd |
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run(cmd) |
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return signature_file.read() |
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def build_verity_table(block_device, data_blocks, root_hash, salt): |
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table = "1 %s %s %s %s %s %s sha256 %s %s" |
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table %= ( block_device, |
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block_device, |
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BLOCK_SIZE, |
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BLOCK_SIZE, |
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data_blocks, |
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data_blocks, |
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root_hash, |
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salt) |
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return table |
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def build_verity_metadata(data_blocks, metadata_image, root_hash, salt, |
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block_device, signer_path, signing_key, signer_args=None): |
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# build the verity table |
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verity_table = build_verity_table(block_device, data_blocks, root_hash, salt) |
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# build the verity table signature |
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signature = sign_verity_table(verity_table, signer_path, signing_key, signer_args) |
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# build the metadata block |
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metadata_block = build_metadata_block(verity_table, signature) |
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# write it to the outfile |
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with open(metadata_image, "wb") as f: |
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f.write(metadata_block) |
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if __name__ == "__main__": |
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parser = argparse.ArgumentParser() |
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subparsers = parser.add_subparsers() |
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parser_size = subparsers.add_parser('size') |
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parser_size.add_argument('partition_size', type=int, action='store', help='partition size') |
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parser_size.set_defaults(dest='size') |
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parser_build = subparsers.add_parser('build') |
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parser_build.add_argument('blocks', type=int, help='data image blocks') |
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parser_build.add_argument('metadata_image', action='store', help='metadata image') |
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parser_build.add_argument('root_hash', action='store', help='root hash') |
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parser_build.add_argument('salt', action='store', help='salt') |
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parser_build.add_argument('block_device', action='store', help='block device') |
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parser_build.add_argument('signer_path', action='store', help='verity signer path') |
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parser_build.add_argument('signing_key', action='store', help='verity signing key') |
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parser_build.add_argument('--signer_args', action='store', help='verity signer args') |
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parser_build.set_defaults(dest='build') |
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args = parser.parse_args() |
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if args.dest == 'size': |
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print get_verity_metadata_size(args.partition_size) |
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else: |
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build_verity_metadata(args.blocks / 4096, args.metadata_image, |
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args.root_hash, args.salt, args.block_device, |
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args.signer_path, args.signing_key, |
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args.signer_args)
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