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//
// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "update_engine/payload_consumer/payload_metadata.h"
#include <endian.h>
#include <base/strings/stringprintf.h>
#include <brillo/data_encoding.h>
#include "update_engine/common/constants.h"
#include "update_engine/common/hash_calculator.h"
#include "update_engine/common/utils.h"
#include "update_engine/payload_consumer/payload_constants.h"
#include "update_engine/payload_consumer/payload_verifier.h"
using std::string;
namespace chromeos_update_engine {
const uint64_t PayloadMetadata::kDeltaVersionOffset = sizeof(kDeltaMagic);
const uint64_t PayloadMetadata::kDeltaVersionSize = 8;
const uint64_t PayloadMetadata::kDeltaManifestSizeOffset =
kDeltaVersionOffset + kDeltaVersionSize;
const uint64_t PayloadMetadata::kDeltaManifestSizeSize = 8;
const uint64_t PayloadMetadata::kDeltaMetadataSignatureSizeSize = 4;
uint64_t PayloadMetadata::GetMetadataSignatureSizeOffset() const {
return kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
}
uint64_t PayloadMetadata::GetManifestOffset() const {
// Actual manifest begins right after the metadata signature size field.
return kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
kDeltaMetadataSignatureSizeSize;
}
MetadataParseResult PayloadMetadata::ParsePayloadHeader(
const brillo::Blob& payload, ErrorCode* error) {
return ParsePayloadHeader(payload.data(), payload.size(), error);
}
MetadataParseResult PayloadMetadata::ParsePayloadHeader(
const unsigned char* payload, size_t size, ErrorCode* error) {
// Ensure we have data to cover the major payload version.
if (size < kDeltaManifestSizeOffset)
return MetadataParseResult::kInsufficientData;
// Validate the magic string.
if (memcmp(payload, kDeltaMagic, sizeof(kDeltaMagic)) != 0) {
LOG(ERROR) << "Bad payload format -- invalid delta magic: "
<< base::StringPrintf("%02x%02x%02x%02x",
payload[0],
payload[1],
payload[2],
payload[3])
<< " Expected: "
<< base::StringPrintf("%02x%02x%02x%02x",
kDeltaMagic[0],
kDeltaMagic[1],
kDeltaMagic[2],
kDeltaMagic[3]);
*error = ErrorCode::kDownloadInvalidMetadataMagicString;
return MetadataParseResult::kError;
}
uint64_t manifest_offset = GetManifestOffset();
// Check again with the manifest offset.
if (size < manifest_offset)
return MetadataParseResult::kInsufficientData;
// Extract the payload version from the metadata.
static_assert(sizeof(major_payload_version_) == kDeltaVersionSize,
"Major payload version size mismatch");
memcpy(&major_payload_version_,
&payload[kDeltaVersionOffset],
kDeltaVersionSize);
// Switch big endian to host.
major_payload_version_ = be64toh(major_payload_version_);
if (major_payload_version_ < kMinSupportedMajorPayloadVersion ||
major_payload_version_ > kMaxSupportedMajorPayloadVersion) {
LOG(ERROR) << "Bad payload format -- unsupported payload version: "
<< major_payload_version_;
*error = ErrorCode::kUnsupportedMajorPayloadVersion;
return MetadataParseResult::kError;
}
// Next, parse the manifest size.
static_assert(sizeof(manifest_size_) == kDeltaManifestSizeSize,
"manifest_size size mismatch");
memcpy(&manifest_size_,
&payload[kDeltaManifestSizeOffset],
kDeltaManifestSizeSize);
manifest_size_ = be64toh(manifest_size_); // switch big endian to host
metadata_size_ = manifest_offset + manifest_size_;
if (metadata_size_ < manifest_size_) {
// Overflow detected.
LOG(ERROR) << "Overflow detected on manifest size.";
*error = ErrorCode::kDownloadInvalidMetadataSize;
return MetadataParseResult::kError;
}
// Parse the metadata signature size.
static_assert(
sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
"metadata_signature_size size mismatch");
uint64_t metadata_signature_size_offset = GetMetadataSignatureSizeOffset();
memcpy(&metadata_signature_size_,
&payload[metadata_signature_size_offset],
kDeltaMetadataSignatureSizeSize);
metadata_signature_size_ = be32toh(metadata_signature_size_);
if (metadata_size_ + metadata_signature_size_ < metadata_size_) {
// Overflow detected.
LOG(ERROR) << "Overflow detected on metadata and signature size.";
*error = ErrorCode::kDownloadInvalidMetadataSize;
return MetadataParseResult::kError;
}
return MetadataParseResult::kSuccess;
}
bool PayloadMetadata::ParsePayloadHeader(const brillo::Blob& payload) {
ErrorCode error;
return ParsePayloadHeader(payload, &error) == MetadataParseResult::kSuccess;
}
bool PayloadMetadata::GetManifest(const brillo::Blob& payload,
DeltaArchiveManifest* out_manifest) const {
return GetManifest(payload.data(), payload.size(), out_manifest);
}
bool PayloadMetadata::GetManifest(const unsigned char* payload,
size_t size,
DeltaArchiveManifest* out_manifest) const {
uint64_t manifest_offset = GetManifestOffset();
CHECK_GE(size, manifest_offset + manifest_size_);
return out_manifest->ParseFromArray(&payload[manifest_offset],
manifest_size_);
}
ErrorCode PayloadMetadata::ValidateMetadataSignature(
const brillo::Blob& payload,
const string& metadata_signature,
const PayloadVerifier& payload_verifier) const {
if (payload.size() < metadata_size_ + metadata_signature_size_)
return ErrorCode::kDownloadMetadataSignatureError;
// A single signature in raw bytes.
brillo::Blob metadata_signature_blob;
// The serialized Signatures protobuf message stored in major version >=2
// payload, it may contain multiple signatures.
string metadata_signature_protobuf;
if (!metadata_signature.empty()) {
// Convert base64-encoded signature to raw bytes.
if (!brillo::data_encoding::Base64Decode(metadata_signature,
&metadata_signature_blob)) {
LOG(ERROR) << "Unable to decode base64 metadata signature: "
<< metadata_signature;
return ErrorCode::kDownloadMetadataSignatureError;
}
} else {
metadata_signature_protobuf.assign(
payload.begin() + metadata_size_,
payload.begin() + metadata_size_ + metadata_signature_size_);
}
if (metadata_signature_blob.empty() && metadata_signature_protobuf.empty()) {
LOG(ERROR) << "Missing mandatory metadata signature in both Omaha "
<< "response and payload.";
return ErrorCode::kDownloadMetadataSignatureMissingError;
}
brillo::Blob metadata_hash;
if (!HashCalculator::RawHashOfBytes(
payload.data(), metadata_size_, &metadata_hash)) {
LOG(ERROR) << "Unable to compute actual hash of manifest";
return ErrorCode::kDownloadMetadataSignatureVerificationError;
}
if (metadata_hash.size() != kSHA256Size) {
LOG(ERROR) << "Computed actual hash of metadata has incorrect size: "
<< metadata_hash.size();
return ErrorCode::kDownloadMetadataSignatureVerificationError;
}
if (!metadata_signature_blob.empty()) {
brillo::Blob decrypted_signature;
if (!payload_verifier.VerifyRawSignature(
metadata_signature_blob, metadata_hash, &decrypted_signature)) {
LOG(ERROR) << "Manifest hash verification failed. Decrypted hash = ";
utils::HexDumpVector(decrypted_signature);
LOG(ERROR) << "Calculated hash before padding = ";
utils::HexDumpVector(metadata_hash);
return ErrorCode::kDownloadMetadataSignatureMismatch;
}
} else {
if (!payload_verifier.VerifySignature(metadata_signature_protobuf,
metadata_hash)) {
LOG(ERROR) << "Manifest hash verification failed.";
return ErrorCode::kDownloadMetadataSignatureMismatch;
}
}
// The autoupdate_CatchBadSignatures test checks for this string in
// log-files. Keep in sync.
LOG(INFO) << "Metadata hash signature matches value in Omaha response.";
return ErrorCode::kSuccess;
}
bool PayloadMetadata::ParsePayloadFile(const string& payload_path,
DeltaArchiveManifest* manifest,
Signatures* metadata_signatures) {
brillo::Blob payload;
TEST_AND_RETURN_FALSE(
utils::ReadFileChunk(payload_path, 0, kMaxPayloadHeaderSize, &payload));
TEST_AND_RETURN_FALSE(ParsePayloadHeader(payload));
if (manifest != nullptr) {
TEST_AND_RETURN_FALSE(
utils::ReadFileChunk(payload_path,
kMaxPayloadHeaderSize,
GetMetadataSize() - kMaxPayloadHeaderSize,
&payload));
TEST_AND_RETURN_FALSE(GetManifest(payload, manifest));
}
if (metadata_signatures != nullptr) {
payload.clear();
TEST_AND_RETURN_FALSE(utils::ReadFileChunk(
payload_path, GetMetadataSize(), GetMetadataSignatureSize(), &payload));
TEST_AND_RETURN_FALSE(
metadata_signatures->ParseFromArray(payload.data(), payload.size()));
}
return true;
}
} // namespace chromeos_update_engine