payload_consumer/payload_metadata.cc - android_system_update_engine - Gitiles

 //
 // 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 <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;

 bool PayloadMetadata::GetMetadataSignatureSizeOffset(
     uint64_t* out_offset) const {
   if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
     *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
     return true;
   }
   return false;
 }

 bool PayloadMetadata::GetManifestOffset(uint64_t* out_offset) const {
   // Actual manifest begins right after the manifest size field or
   // metadata signature size field if major version >= 2.
   if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
     *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
     return true;
   }
   if (major_payload_version_ == kBrilloMajorPayloadVersion) {
     *out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
                   kDeltaMetadataSignatureSizeSize;
     return true;
   }
   LOG(ERROR) << "Unknown major payload version: " << major_payload_version_;
   return false;
 }

 MetadataParseResult PayloadMetadata::ParsePayloadHeader(
     const brillo::Blob& payload, ErrorCode* error) {
   uint64_t manifest_offset;
   // Ensure we have data to cover the major payload version.
   if (payload.size() < kDeltaManifestSizeOffset)
     return MetadataParseResult::kInsufficientData;

   // Validate the magic string.
   if (memcmp(payload.data(), kDeltaMagic, sizeof(kDeltaMagic)) != 0) {
     LOG(ERROR) << "Bad payload format -- invalid delta magic.";
     *error = ErrorCode::kDownloadInvalidMetadataMagicString;
     return MetadataParseResult::kError;
   }

   // 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;
   }

   // Get the manifest offset now that we have payload version.
   if (!GetManifestOffset(&manifest_offset)) {
     *error = ErrorCode::kUnsupportedMajorPayloadVersion;
     return MetadataParseResult::kError;
   }
   // Check again with the manifest offset.
   if (payload.size() < manifest_offset)
     return MetadataParseResult::kInsufficientData;

   // 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.
     *error = ErrorCode::kDownloadInvalidMetadataSize;
     return MetadataParseResult::kError;
   }

   if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
     // Parse the metadata signature size.
     static_assert(
         sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
         "metadata_signature_size size mismatch");
     uint64_t metadata_signature_size_offset;
     if (!GetMetadataSignatureSizeOffset(&metadata_signature_size_offset)) {
       *error = ErrorCode::kError;
       return MetadataParseResult::kError;
     }
     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.
       *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 {
   uint64_t manifest_offset;
   if (!GetManifestOffset(&manifest_offset))
     return false;
   CHECK_GE(payload.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 if (major_payload_version_ == kBrilloMajorPayloadVersion) {
     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;
 }

 }  // namespace chromeos_update_engine
	//
	// 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 <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;

	bool PayloadMetadata::GetMetadataSignatureSizeOffset(
	uint64_t* out_offset) const {
	if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
	*out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
	return true;
	}
	return false;
	}

	bool PayloadMetadata::GetManifestOffset(uint64_t* out_offset) const {
	// Actual manifest begins right after the manifest size field or
	// metadata signature size field if major version >= 2.
	if (major_payload_version_ == kChromeOSMajorPayloadVersion) {
	*out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize;
	return true;
	}
	if (major_payload_version_ == kBrilloMajorPayloadVersion) {
	*out_offset = kDeltaManifestSizeOffset + kDeltaManifestSizeSize +
	kDeltaMetadataSignatureSizeSize;
	return true;
	}
	LOG(ERROR) << "Unknown major payload version: " << major_payload_version_;
	return false;
	}

	MetadataParseResult PayloadMetadata::ParsePayloadHeader(
	const brillo::Blob& payload, ErrorCode* error) {
	uint64_t manifest_offset;
	// Ensure we have data to cover the major payload version.
	if (payload.size() < kDeltaManifestSizeOffset)
	return MetadataParseResult::kInsufficientData;

	// Validate the magic string.
	if (memcmp(payload.data(), kDeltaMagic, sizeof(kDeltaMagic)) != 0) {
	LOG(ERROR) << "Bad payload format -- invalid delta magic.";
	*error = ErrorCode::kDownloadInvalidMetadataMagicString;
	return MetadataParseResult::kError;
	}

	// 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;
	}

	// Get the manifest offset now that we have payload version.
	if (!GetManifestOffset(&manifest_offset)) {
	*error = ErrorCode::kUnsupportedMajorPayloadVersion;
	return MetadataParseResult::kError;
	}
	// Check again with the manifest offset.
	if (payload.size() < manifest_offset)
	return MetadataParseResult::kInsufficientData;

	// 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.
	*error = ErrorCode::kDownloadInvalidMetadataSize;
	return MetadataParseResult::kError;
	}

	if (GetMajorVersion() == kBrilloMajorPayloadVersion) {
	// Parse the metadata signature size.
	static_assert(
	sizeof(metadata_signature_size_) == kDeltaMetadataSignatureSizeSize,
	"metadata_signature_size size mismatch");
	uint64_t metadata_signature_size_offset;
	if (!GetMetadataSignatureSizeOffset(&metadata_signature_size_offset)) {
	*error = ErrorCode::kError;
	return MetadataParseResult::kError;
	}
	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.
	*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 {
	uint64_t manifest_offset;
	if (!GetManifestOffset(&manifest_offset))
	return false;
	CHECK_GE(payload.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 if (major_payload_version_ == kBrilloMajorPayloadVersion) {
	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;
	}

	} // namespace chromeos_update_engine