f6fe0a9c9c
brillo_update_payload is thin bash wrapper for delta_generator, and OTA tools are wrappers around brillo_update_payload. This is inconveinent, as adding a new flag requires changing 3 places. Since brillo_update_payload is really thin, skip it and invoke delta_generator directly. Test: th Bug: 293313353 Change-Id: I2fd5af95c571ea45aea62f9eec475f0f4e864953
126 lines
5.3 KiB
Python
126 lines
5.3 KiB
Python
#!/usr/bin/env python3
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#
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# Copyright (C) 2022 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 common
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import logging
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from common import OPTIONS
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logger = logging.getLogger(__name__)
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class PayloadSigner(object):
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"""A class that wraps the payload signing works.
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When generating a Payload, hashes of the payload and metadata files will be
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signed with the device key, either by calling an external payload signer or
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by calling openssl with the package key. This class provides a unified
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interface, so that callers can just call PayloadSigner.Sign().
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If an external payload signer has been specified (OPTIONS.payload_signer), it
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calls the signer with the provided args (OPTIONS.payload_signer_args). Note
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that the signing key should be provided as part of the payload_signer_args.
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Otherwise without an external signer, it uses the package key
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(OPTIONS.package_key) and calls openssl for the signing works.
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"""
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def __init__(self, package_key=None, private_key_suffix=None, pw=None, payload_signer=None,
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payload_signer_args=None, payload_signer_maximum_signature_size=None):
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if package_key is None:
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package_key = OPTIONS.package_key
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if private_key_suffix is None:
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private_key_suffix = OPTIONS.private_key_suffix
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if payload_signer_args is None:
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payload_signer_args = OPTIONS.payload_signer_args
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if payload_signer_maximum_signature_size is None:
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payload_signer_maximum_signature_size = OPTIONS.payload_signer_maximum_signature_size
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if payload_signer is None:
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# Prepare the payload signing key.
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private_key = package_key + private_key_suffix
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cmd = ["openssl", "pkcs8", "-in", private_key, "-inform", "DER"]
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cmd.extend(["-passin", "pass:" + pw] if pw else ["-nocrypt"])
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signing_key = common.MakeTempFile(prefix="key-", suffix=".key")
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cmd.extend(["-out", signing_key])
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common.RunAndCheckOutput(cmd, verbose=True)
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self.signer = "openssl"
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self.signer_args = ["pkeyutl", "-sign", "-inkey", signing_key,
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"-pkeyopt", "digest:sha256"]
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self.maximum_signature_size = self._GetMaximumSignatureSizeInBytes(
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signing_key)
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else:
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self.signer = payload_signer
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self.signer_args = payload_signer_args
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if payload_signer_maximum_signature_size:
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self.maximum_signature_size = int(
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payload_signer_maximum_signature_size)
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else:
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# The legacy config uses RSA2048 keys.
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logger.warning("The maximum signature size for payload signer is not"
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" set, default to 256 bytes.")
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self.maximum_signature_size = 256
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@staticmethod
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def _GetMaximumSignatureSizeInBytes(signing_key):
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out_signature_size_file = common.MakeTempFile("signature_size")
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cmd = ["delta_generator", "--out_maximum_signature_size_file={}".format(
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out_signature_size_file), "--private_key={}".format(signing_key)]
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common.RunAndCheckOutput(cmd, verbose=True)
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with open(out_signature_size_file) as f:
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signature_size = f.read().rstrip()
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logger.info("%s outputs the maximum signature size: %s", cmd[0],
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signature_size)
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return int(signature_size)
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@staticmethod
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def _Run(cmd):
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common.RunAndCheckOutput(cmd, stdout=None, stderr=None)
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def SignPayload(self, unsigned_payload):
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# 1. Generate hashes of the payload and metadata files.
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payload_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
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metadata_sig_file = common.MakeTempFile(prefix="sig-", suffix=".bin")
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cmd = ["delta_generator",
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"--in_file=" + unsigned_payload,
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"--signature_size=" + str(self.maximum_signature_size),
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"--out_metadata_hash_file=" + metadata_sig_file,
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"--out_hash_file=" + payload_sig_file]
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self._Run(cmd)
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# 2. Sign the hashes.
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signed_payload_sig_file = self.SignHashFile(payload_sig_file)
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signed_metadata_sig_file = self.SignHashFile(metadata_sig_file)
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# 3. Insert the signatures back into the payload file.
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signed_payload_file = common.MakeTempFile(prefix="signed-payload-",
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suffix=".bin")
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cmd = ["delta_generator",
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"--in_file=" + unsigned_payload,
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"--out_file=" + signed_payload_file,
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"--signature_size=" + str(self.maximum_signature_size),
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"--metadata_signature_file=" + signed_metadata_sig_file,
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"--payload_signature_file=" + signed_payload_sig_file]
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self._Run(cmd)
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return signed_payload_file
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def SignHashFile(self, in_file):
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"""Signs the given input file. Returns the output filename."""
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out_file = common.MakeTempFile(prefix="signed-", suffix=".bin")
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cmd = [self.signer] + self.signer_args + ['-in', in_file, '-out', out_file]
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common.RunAndCheckOutput(cmd)
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return out_file
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