//
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// Copyright (C) 2011 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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//
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#include "update_engine/payload_generator/payload_signer.h"
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#include <endian.h>
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#include <utility>
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#include <base/logging.h>
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#include <base/strings/string_number_conversions.h>
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#include <base/strings/string_split.h>
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#include <base/strings/string_util.h>
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#include <brillo/data_encoding.h>
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#include <openssl/err.h>
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#include <openssl/pem.h>
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#include "update_engine/common/constants.h"
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#include "update_engine/common/hash_calculator.h"
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#include "update_engine/common/subprocess.h"
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#include "update_engine/common/utils.h"
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#include "update_engine/payload_consumer/delta_performer.h"
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#include "update_engine/payload_consumer/payload_constants.h"
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#include "update_engine/payload_consumer/payload_metadata.h"
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#include "update_engine/payload_consumer/payload_verifier.h"
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#include "update_engine/payload_generator/delta_diff_generator.h"
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#include "update_engine/payload_generator/payload_file.h"
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#include "update_engine/update_metadata.pb.h"
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using std::string;
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using std::vector;
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namespace chromeos_update_engine {
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namespace {
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// The payload verifier will check all the signatures included in the payload
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// regardless of the version field. Old version of the verifier require the
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// version field to be included and be 1.
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const uint32_t kSignatureMessageLegacyVersion = 1;
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// Given raw |signatures|, packs them into a protobuf and serializes it into a
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// string. Returns true on success, false otherwise.
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bool ConvertSignaturesToProtobuf(const vector<brillo::Blob>& signatures,
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string* out_serialized_signature) {
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// Pack it into a protobuf
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Signatures out_message;
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for (const brillo::Blob& signature : signatures) {
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Signatures::Signature* sig_message = out_message.add_signatures();
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// Set all the signatures with the same version number.
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sig_message->set_version(kSignatureMessageLegacyVersion);
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sig_message->set_data(signature.data(), signature.size());
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}
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// Serialize protobuf
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TEST_AND_RETURN_FALSE(
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out_message.SerializeToString(out_serialized_signature));
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LOG(INFO) << "Signature blob size: " << out_serialized_signature->size();
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return true;
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}
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// Given an unsigned payload under |payload_path| and the |payload_signature|
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// and |metadata_signature| generates an updated payload that includes the
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// signatures. It populates |out_metadata_size| with the size of the final
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// manifest after adding the dummy signature operation, and
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// |out_signatures_offset| with the expected offset for the new blob, and
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// |out_metadata_signature_size| which will be size of |metadata_signature|
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// if the payload major version supports metadata signature, 0 otherwise.
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// Returns true on success, false otherwise.
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bool AddSignatureBlobToPayload(const string& payload_path,
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const string& payload_signature,
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const string& metadata_signature,
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brillo::Blob* out_payload,
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uint64_t* out_metadata_size,
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uint32_t* out_metadata_signature_size,
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uint64_t* out_signatures_offset) {
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uint64_t manifest_offset = 20;
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const int kProtobufSizeOffset = 12;
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brillo::Blob payload;
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TEST_AND_RETURN_FALSE(utils::ReadFile(payload_path, &payload));
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PayloadMetadata payload_metadata;
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TEST_AND_RETURN_FALSE(payload_metadata.ParsePayloadHeader(payload));
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uint64_t metadata_size = payload_metadata.GetMetadataSize();
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uint32_t metadata_signature_size =
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payload_metadata.GetMetadataSignatureSize();
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if (payload_metadata.GetMajorVersion() == kBrilloMajorPayloadVersion) {
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// Write metadata signature size in header.
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uint32_t metadata_signature_size_be = htobe32(metadata_signature.size());
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memcpy(payload.data() + manifest_offset,
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&metadata_signature_size_be,
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sizeof(metadata_signature_size_be));
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manifest_offset += sizeof(metadata_signature_size_be);
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// Replace metadata signature.
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payload.erase(payload.begin() + metadata_size,
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payload.begin() + metadata_size + metadata_signature_size);
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payload.insert(payload.begin() + metadata_size,
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metadata_signature.begin(),
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metadata_signature.end());
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metadata_signature_size = metadata_signature.size();
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LOG(INFO) << "Metadata signature size: " << metadata_signature_size;
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}
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DeltaArchiveManifest manifest;
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TEST_AND_RETURN_FALSE(payload_metadata.GetManifest(payload, &manifest));
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// Is there already a signature op in place?
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if (manifest.has_signatures_size()) {
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// The signature op is tied to the size of the signature blob, but not it's
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// contents. We don't allow the manifest to change if there is already an op
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// present, because that might invalidate previously generated
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// hashes/signatures.
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if (manifest.signatures_size() != payload_signature.size()) {
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LOG(ERROR) << "Attempt to insert different signature sized blob. "
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<< "(current:" << manifest.signatures_size()
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<< "new:" << payload_signature.size() << ")";
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return false;
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}
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LOG(INFO) << "Matching signature sizes already present.";
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} else {
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// Updates the manifest to include the signature operation.
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PayloadSigner::AddSignatureToManifest(
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payload.size() - metadata_size - metadata_signature_size,
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payload_signature.size(),
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payload_metadata.GetMajorVersion() == kChromeOSMajorPayloadVersion,
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&manifest);
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// Updates the payload to include the new manifest.
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string serialized_manifest;
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TEST_AND_RETURN_FALSE(manifest.AppendToString(&serialized_manifest));
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LOG(INFO) << "Updated protobuf size: " << serialized_manifest.size();
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payload.erase(payload.begin() + manifest_offset,
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payload.begin() + metadata_size);
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payload.insert(payload.begin() + manifest_offset,
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serialized_manifest.begin(),
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serialized_manifest.end());
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// Updates the protobuf size.
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uint64_t size_be = htobe64(serialized_manifest.size());
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memcpy(&payload[kProtobufSizeOffset], &size_be, sizeof(size_be));
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metadata_size = serialized_manifest.size() + manifest_offset;
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LOG(INFO) << "Updated payload size: " << payload.size();
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LOG(INFO) << "Updated metadata size: " << metadata_size;
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}
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uint64_t signatures_offset =
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metadata_size + metadata_signature_size + manifest.signatures_offset();
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LOG(INFO) << "Signature Blob Offset: " << signatures_offset;
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payload.resize(signatures_offset);
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payload.insert(payload.begin() + signatures_offset,
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payload_signature.begin(),
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payload_signature.end());
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*out_payload = std::move(payload);
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*out_metadata_size = metadata_size;
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*out_metadata_signature_size = metadata_signature_size;
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*out_signatures_offset = signatures_offset;
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return true;
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}
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// Given a |payload| with correct signature op and metadata signature size in
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// header and |metadata_size|, |metadata_signature_size|, |signatures_offset|,
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// calculate hash for payload and metadata, save it to |out_hash_data| and
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// |out_metadata_hash|.
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bool CalculateHashFromPayload(const brillo::Blob& payload,
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const uint64_t metadata_size,
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const uint32_t metadata_signature_size,
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const uint64_t signatures_offset,
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brillo::Blob* out_hash_data,
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brillo::Blob* out_metadata_hash) {
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if (out_metadata_hash) {
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// Calculates the hash on the manifest.
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TEST_AND_RETURN_FALSE(HashCalculator::RawHashOfBytes(
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payload.data(), metadata_size, out_metadata_hash));
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}
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if (out_hash_data) {
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// Calculates the hash on the updated payload. Note that we skip metadata
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// signature and payload signature.
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HashCalculator calc;
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TEST_AND_RETURN_FALSE(calc.Update(payload.data(), metadata_size));
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TEST_AND_RETURN_FALSE(signatures_offset >=
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metadata_size + metadata_signature_size);
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TEST_AND_RETURN_FALSE(calc.Update(
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payload.data() + metadata_size + metadata_signature_size,
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signatures_offset - metadata_size - metadata_signature_size));
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TEST_AND_RETURN_FALSE(calc.Finalize());
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*out_hash_data = calc.raw_hash();
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}
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return true;
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}
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} // namespace
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void PayloadSigner::AddSignatureToManifest(uint64_t signature_blob_offset,
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uint64_t signature_blob_length,
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bool add_dummy_op,
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DeltaArchiveManifest* manifest) {
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LOG(INFO) << "Making room for signature in file";
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manifest->set_signatures_offset(signature_blob_offset);
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LOG(INFO) << "set? " << manifest->has_signatures_offset();
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manifest->set_signatures_offset(signature_blob_offset);
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manifest->set_signatures_size(signature_blob_length);
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// Add a dummy op at the end to appease older clients
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if (add_dummy_op) {
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InstallOperation* dummy_op = manifest->add_kernel_install_operations();
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dummy_op->set_type(InstallOperation::REPLACE);
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dummy_op->set_data_offset(signature_blob_offset);
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dummy_op->set_data_length(signature_blob_length);
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Extent* dummy_extent = dummy_op->add_dst_extents();
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// Tell the dummy op to write this data to a big sparse hole
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dummy_extent->set_start_block(kSparseHole);
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dummy_extent->set_num_blocks(
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utils::DivRoundUp(signature_blob_length, kBlockSize));
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}
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}
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bool PayloadSigner::VerifySignedPayload(const string& payload_path,
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const string& public_key_path) {
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brillo::Blob payload;
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TEST_AND_RETURN_FALSE(utils::ReadFile(payload_path, &payload));
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PayloadMetadata payload_metadata;
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TEST_AND_RETURN_FALSE(payload_metadata.ParsePayloadHeader(payload));
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DeltaArchiveManifest manifest;
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TEST_AND_RETURN_FALSE(payload_metadata.GetManifest(payload, &manifest));
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TEST_AND_RETURN_FALSE(manifest.has_signatures_offset() &&
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manifest.has_signatures_size());
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uint64_t metadata_size = payload_metadata.GetMetadataSize();
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uint32_t metadata_signature_size =
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payload_metadata.GetMetadataSignatureSize();
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uint64_t signatures_offset =
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metadata_size + metadata_signature_size + manifest.signatures_offset();
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CHECK_EQ(payload.size(), signatures_offset + manifest.signatures_size());
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brillo::Blob payload_hash, metadata_hash;
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TEST_AND_RETURN_FALSE(CalculateHashFromPayload(payload,
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metadata_size,
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metadata_signature_size,
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signatures_offset,
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&payload_hash,
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&metadata_hash));
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string signature(payload.begin() + signatures_offset, payload.end());
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string public_key;
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TEST_AND_RETURN_FALSE(utils::ReadFile(public_key_path, &public_key));
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TEST_AND_RETURN_FALSE(payload_hash.size() == kSHA256Size);
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TEST_AND_RETURN_FALSE(
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PayloadVerifier::VerifySignature(signature, public_key, payload_hash));
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if (metadata_signature_size) {
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signature.assign(payload.begin() + metadata_size,
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payload.begin() + metadata_size + metadata_signature_size);
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TEST_AND_RETURN_FALSE(metadata_hash.size() == kSHA256Size);
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TEST_AND_RETURN_FALSE(
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PayloadVerifier::VerifySignature(signature, public_key, metadata_hash));
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}
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return true;
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}
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bool PayloadSigner::SignHash(const brillo::Blob& hash,
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const string& private_key_path,
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brillo::Blob* out_signature) {
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LOG(INFO) << "Signing hash with private key: " << private_key_path;
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// We expect unpadded SHA256 hash coming in
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TEST_AND_RETURN_FALSE(hash.size() == kSHA256Size);
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// The code below executes the equivalent of:
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//
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// openssl rsautl -raw -sign -inkey |private_key_path|
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// -in |padded_hash| -out |out_signature|
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FILE* fprikey = fopen(private_key_path.c_str(), "rb");
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TEST_AND_RETURN_FALSE(fprikey != nullptr);
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RSA* rsa = PEM_read_RSAPrivateKey(fprikey, nullptr, nullptr, nullptr);
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fclose(fprikey);
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TEST_AND_RETURN_FALSE(rsa != nullptr);
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brillo::Blob padded_hash = hash;
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PayloadVerifier::PadRSASHA256Hash(&padded_hash, RSA_size(rsa));
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brillo::Blob signature(RSA_size(rsa));
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ssize_t signature_size = RSA_private_encrypt(padded_hash.size(),
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padded_hash.data(),
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signature.data(),
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rsa,
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RSA_NO_PADDING);
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RSA_free(rsa);
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if (signature_size < 0) {
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LOG(ERROR) << "Signing hash failed: "
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<< ERR_error_string(ERR_get_error(), nullptr);
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return false;
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}
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TEST_AND_RETURN_FALSE(static_cast<size_t>(signature_size) ==
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signature.size());
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out_signature->swap(signature);
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return true;
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}
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bool PayloadSigner::SignHashWithKeys(const brillo::Blob& hash_data,
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const vector<string>& private_key_paths,
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string* out_serialized_signature) {
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vector<brillo::Blob> signatures;
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for (const string& path : private_key_paths) {
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brillo::Blob signature;
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TEST_AND_RETURN_FALSE(SignHash(hash_data, path, &signature));
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signatures.push_back(signature);
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}
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TEST_AND_RETURN_FALSE(
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ConvertSignaturesToProtobuf(signatures, out_serialized_signature));
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return true;
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}
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bool PayloadSigner::SignPayload(const string& unsigned_payload_path,
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const vector<string>& private_key_paths,
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const uint64_t metadata_size,
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const uint32_t metadata_signature_size,
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const uint64_t signatures_offset,
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string* out_serialized_signature) {
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brillo::Blob payload;
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TEST_AND_RETURN_FALSE(utils::ReadFile(unsigned_payload_path, &payload));
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brillo::Blob hash_data;
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TEST_AND_RETURN_FALSE(CalculateHashFromPayload(payload,
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metadata_size,
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metadata_signature_size,
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signatures_offset,
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&hash_data,
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nullptr));
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TEST_AND_RETURN_FALSE(
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SignHashWithKeys(hash_data, private_key_paths, out_serialized_signature));
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return true;
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}
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bool PayloadSigner::SignatureBlobLength(const vector<string>& private_key_paths,
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uint64_t* out_length) {
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DCHECK(out_length);
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brillo::Blob hash_blob;
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TEST_AND_RETURN_FALSE(HashCalculator::RawHashOfData({'x'}, &hash_blob));
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string sig_blob;
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TEST_AND_RETURN_FALSE(
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SignHashWithKeys(hash_blob, private_key_paths, &sig_blob));
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*out_length = sig_blob.size();
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return true;
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}
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bool PayloadSigner::HashPayloadForSigning(const string& payload_path,
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const vector<int>& signature_sizes,
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brillo::Blob* out_payload_hash_data,
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brillo::Blob* out_metadata_hash) {
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// Create a signature blob with signatures filled with 0.
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// Will be used for both payload signature and metadata signature.
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vector<brillo::Blob> signatures;
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for (int signature_size : signature_sizes) {
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signatures.emplace_back(signature_size, 0);
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}
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string signature;
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TEST_AND_RETURN_FALSE(ConvertSignaturesToProtobuf(signatures, &signature));
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brillo::Blob payload;
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uint64_t metadata_size, signatures_offset;
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uint32_t metadata_signature_size;
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// Prepare payload for hashing.
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TEST_AND_RETURN_FALSE(AddSignatureBlobToPayload(payload_path,
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signature,
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signature,
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&payload,
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&metadata_size,
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&metadata_signature_size,
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&signatures_offset));
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TEST_AND_RETURN_FALSE(CalculateHashFromPayload(payload,
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metadata_size,
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metadata_signature_size,
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signatures_offset,
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out_payload_hash_data,
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out_metadata_hash));
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return true;
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}
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bool PayloadSigner::AddSignatureToPayload(
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const string& payload_path,
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const vector<brillo::Blob>& payload_signatures,
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const vector<brillo::Blob>& metadata_signatures,
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const string& signed_payload_path,
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uint64_t* out_metadata_size) {
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// TODO(petkov): Reduce memory usage -- the payload is manipulated in memory.
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// Loads the payload and adds the signature op to it.
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string payload_signature, metadata_signature;
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TEST_AND_RETURN_FALSE(
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ConvertSignaturesToProtobuf(payload_signatures, &payload_signature));
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if (!metadata_signatures.empty()) {
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TEST_AND_RETURN_FALSE(
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ConvertSignaturesToProtobuf(metadata_signatures, &metadata_signature));
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}
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brillo::Blob payload;
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uint64_t signatures_offset;
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uint32_t metadata_signature_size;
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TEST_AND_RETURN_FALSE(AddSignatureBlobToPayload(payload_path,
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payload_signature,
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metadata_signature,
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&payload,
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out_metadata_size,
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&metadata_signature_size,
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&signatures_offset));
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LOG(INFO) << "Signed payload size: " << payload.size();
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TEST_AND_RETURN_FALSE(utils::WriteFile(
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signed_payload_path.c_str(), payload.data(), payload.size()));
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return true;
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}
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bool PayloadSigner::GetMetadataSignature(const void* const metadata,
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size_t metadata_size,
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const string& private_key_path,
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string* out_signature) {
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// Calculates the hash on the updated payload. Note that the payload includes
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// the signature op but doesn't include the signature blob at the end.
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brillo::Blob metadata_hash;
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TEST_AND_RETURN_FALSE(
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HashCalculator::RawHashOfBytes(metadata, metadata_size, &metadata_hash));
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brillo::Blob signature;
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TEST_AND_RETURN_FALSE(SignHash(metadata_hash, private_key_path, &signature));
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*out_signature = brillo::data_encoding::Base64Encode(signature);
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return true;
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}
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bool PayloadSigner::ExtractPayloadProperties(
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const string& payload_path, brillo::KeyValueStore* properties) {
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brillo::Blob payload;
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TEST_AND_RETURN_FALSE(
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utils::ReadFileChunk(payload_path, 0, kMaxPayloadHeaderSize, &payload));
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PayloadMetadata payload_metadata;
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TEST_AND_RETURN_FALSE(payload_metadata.ParsePayloadHeader(payload));
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uint64_t metadata_size = payload_metadata.GetMetadataSize();
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uint64_t file_size = utils::FileSize(payload_path);
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properties->SetString(kPayloadPropertyFileSize, std::to_string(file_size));
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properties->SetString(kPayloadPropertyMetadataSize,
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std::to_string(metadata_size));
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brillo::Blob file_hash, metadata_hash;
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TEST_AND_RETURN_FALSE(
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HashCalculator::RawHashOfFile(payload_path, file_size, &file_hash) ==
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static_cast<off_t>(file_size));
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TEST_AND_RETURN_FALSE(HashCalculator::RawHashOfFile(
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payload_path, metadata_size, &metadata_hash) ==
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static_cast<off_t>(metadata_size));
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properties->SetString(kPayloadPropertyFileHash,
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brillo::data_encoding::Base64Encode(file_hash));
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properties->SetString(kPayloadPropertyMetadataHash,
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brillo::data_encoding::Base64Encode(metadata_hash));
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return true;
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}
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} // namespace chromeos_update_engine
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