| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "components/variations/variations_seed_store.h" |
| |
| #include <stdint.h> |
| #include <utility> |
| |
| #include "base/base64.h" |
| #include "base/callback_helpers.h" |
| #include "base/logging.h" |
| #include "base/metrics/histogram_macros.h" |
| #include "base/numerics/safe_math.h" |
| #include "base/strings/string_number_conversions.h" |
| #include "build/build_config.h" |
| #include "components/prefs/pref_registry_simple.h" |
| #include "components/prefs/pref_service.h" |
| #include "components/variations/client_filterable_state.h" |
| #include "components/variations/pref_names.h" |
| #include "components/variations/proto/variations_seed.pb.h" |
| #include "components/version_info/version_info.h" |
| #include "crypto/signature_verifier.h" |
| #include "third_party/protobuf/src/google/protobuf/io/coded_stream.h" |
| #include "third_party/zlib/google/compression_utils.h" |
| |
| #if BUILDFLAG(IS_ANDROID) |
| #include "components/variations/android/variations_seed_bridge.h" |
| #include "components/variations/metrics.h" |
| #endif // BUILDFLAG(IS_ANDROID) |
| |
| namespace variations { |
| namespace { |
| |
| // The ECDSA public key of the variations server for verifying variations seed |
| // signatures. |
| const uint8_t kPublicKey[] = { |
| 0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02, |
| 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03, |
| 0x42, 0x00, 0x04, 0x51, 0x7c, 0x31, 0x4b, 0x50, 0x42, 0xdd, 0x59, 0xda, |
| 0x0b, 0xfa, 0x43, 0x44, 0x33, 0x7c, 0x5f, 0xa1, 0x0b, 0xd5, 0x82, 0xf6, |
| 0xac, 0x04, 0x19, 0x72, 0x6c, 0x40, 0xd4, 0x3e, 0x56, 0xe2, 0xa0, 0x80, |
| 0xa0, 0x41, 0xb3, 0x23, 0x7b, 0x71, 0xc9, 0x80, 0x87, 0xde, 0x35, 0x0d, |
| 0x25, 0x71, 0x09, 0x7f, 0xb4, 0x15, 0x2b, 0xff, 0x82, 0x4d, 0xd3, 0xfe, |
| 0xc5, 0xef, 0x20, 0xc6, 0xa3, 0x10, 0xbf, |
| }; |
| |
| // A sentinel value that may be stored as the latest variations seed value in |
| // prefs to indicate that the latest seed is identical to the safe seed. Used to |
| // avoid duplicating storage space. |
| constexpr char kIdenticalToSafeSeedSentinel[] = "safe_seed_content"; |
| |
| // Verifies a variations seed (the serialized proto bytes) with the specified |
| // base-64 encoded signature that was received from the server and returns the |
| // result. The signature is assumed to be an "ECDSA with SHA-256" signature |
| // (see kECDSAWithSHA256AlgorithmID in the .cc file). Returns the result of |
| // signature verification. |
| VerifySignatureResult VerifySeedSignature( |
| const std::string& seed_bytes, |
| const std::string& base64_seed_signature) { |
| if (base64_seed_signature.empty()) |
| return VerifySignatureResult::MISSING_SIGNATURE; |
| |
| std::string signature; |
| if (!base::Base64Decode(base64_seed_signature, &signature)) |
| return VerifySignatureResult::DECODE_FAILED; |
| |
| crypto::SignatureVerifier verifier; |
| if (!verifier.VerifyInit(crypto::SignatureVerifier::ECDSA_SHA256, |
| base::as_bytes(base::make_span(signature)), |
| kPublicKey)) { |
| return VerifySignatureResult::INVALID_SIGNATURE; |
| } |
| |
| verifier.VerifyUpdate(base::as_bytes(base::make_span(seed_bytes))); |
| if (!verifier.VerifyFinal()) |
| return VerifySignatureResult::INVALID_SEED; |
| |
| return VerifySignatureResult::VALID_SIGNATURE; |
| } |
| |
| // Truncates a time to the start of the day in UTC. If given a time representing |
| // 2014-03-11 10:18:03.1 UTC, it will return a time representing |
| // 2014-03-11 00:00:00.0 UTC. |
| base::Time TruncateToUTCDay(const base::Time& time) { |
| base::Time::Exploded exploded; |
| time.UTCExplode(&exploded); |
| exploded.hour = 0; |
| exploded.minute = 0; |
| exploded.second = 0; |
| exploded.millisecond = 0; |
| |
| base::Time out_time; |
| bool conversion_success = base::Time::FromUTCExploded(exploded, &out_time); |
| DCHECK(conversion_success); |
| return out_time; |
| } |
| |
| UpdateSeedDateResult GetSeedDateChangeState( |
| const base::Time& server_seed_date, |
| const base::Time& stored_seed_date) { |
| if (server_seed_date < stored_seed_date) |
| return UpdateSeedDateResult::NEW_DATE_IS_OLDER; |
| |
| if (TruncateToUTCDay(server_seed_date) != |
| TruncateToUTCDay(stored_seed_date)) { |
| // The server date is later than the stored date, and they are from |
| // different UTC days, so |server_seed_date| is a valid new day. |
| return UpdateSeedDateResult::NEW_DAY; |
| } |
| return UpdateSeedDateResult::SAME_DAY; |
| } |
| |
| // Remove gzip compression from |data|. |
| // Returns success or error, populating result on success. |
| StoreSeedResult Uncompress(const std::string& compressed, std::string* result) { |
| DCHECK(result); |
| if (!compression::GzipUncompress(compressed, result)) |
| return StoreSeedResult::kFailedUngzip; |
| if (result->empty()) |
| return StoreSeedResult::kFailedEmptyGzipContents; |
| return StoreSeedResult::kSuccess; |
| } |
| |
| } // namespace |
| |
| VariationsSeedStore::VariationsSeedStore(PrefService* local_state) |
| : VariationsSeedStore(local_state, nullptr, true) {} |
| |
| VariationsSeedStore::VariationsSeedStore( |
| PrefService* local_state, |
| std::unique_ptr<SeedResponse> initial_seed, |
| bool signature_verification_enabled, |
| bool use_first_run_prefs) |
| : local_state_(local_state), |
| signature_verification_enabled_(signature_verification_enabled), |
| use_first_run_prefs_(use_first_run_prefs) { |
| #if BUILDFLAG(IS_ANDROID) |
| if (initial_seed) |
| ImportInitialSeed(std::move(initial_seed)); |
| #endif // BUILDFLAG(IS_ANDROID) |
| } |
| |
| VariationsSeedStore::~VariationsSeedStore() = default; |
| |
| bool VariationsSeedStore::LoadSeed(VariationsSeed* seed, |
| std::string* seed_data, |
| std::string* base64_seed_signature) { |
| LoadSeedResult result = |
| LoadSeedImpl(SeedType::LATEST, seed, seed_data, base64_seed_signature); |
| RecordLoadSeedResult(result); |
| if (result != LoadSeedResult::kSuccess) |
| return false; |
| |
| latest_serial_number_ = seed->serial_number(); |
| return true; |
| } |
| |
| bool VariationsSeedStore::StoreSeedData( |
| const std::string& data, |
| const std::string& base64_seed_signature, |
| const std::string& country_code, |
| const base::Time& date_fetched, |
| bool is_delta_compressed, |
| bool is_gzip_compressed, |
| VariationsSeed* parsed_seed) { |
| UMA_HISTOGRAM_COUNTS_1000("Variations.StoreSeed.DataSize", |
| data.length() / 1024); |
| InstanceManipulations im = { |
| .gzip_compressed = is_gzip_compressed, |
| .delta_compressed = is_delta_compressed, |
| }; |
| RecordSeedInstanceManipulations(im); |
| std::string seed_bytes; |
| StoreSeedResult im_result = |
| ResolveInstanceManipulations(data, im, &seed_bytes); |
| if (im_result != StoreSeedResult::kSuccess) { |
| RecordStoreSeedResult(im_result); |
| return false; |
| }; |
| |
| ValidatedSeed validated; |
| StoreSeedResult validate_result = ValidateSeedBytes( |
| seed_bytes, base64_seed_signature, SeedType::LATEST, &validated); |
| if (validate_result != StoreSeedResult::kSuccess) { |
| RecordStoreSeedResult(validate_result); |
| if (im.delta_compressed) |
| RecordStoreSeedResult(StoreSeedResult::kFailedDeltaStore); |
| return false; |
| } |
| |
| StoreSeedResult result = |
| StoreValidatedSeed(validated, country_code, date_fetched); |
| RecordStoreSeedResult(result); |
| if (result != StoreSeedResult::kSuccess) { |
| if (im.delta_compressed) |
| RecordStoreSeedResult(StoreSeedResult::kFailedDeltaStore); |
| return false; |
| } |
| if (parsed_seed) |
| parsed_seed->Swap(&validated.parsed); |
| return true; |
| } |
| |
| bool VariationsSeedStore::LoadSafeSeed(VariationsSeed* seed, |
| ClientFilterableState* client_state) { |
| std::string unused_seed_data; |
| std::string unused_base64_seed_signature; |
| LoadSeedResult result = LoadSeedImpl(SeedType::SAFE, seed, &unused_seed_data, |
| &unused_base64_seed_signature); |
| RecordLoadSafeSeedResult(result); |
| if (result != LoadSeedResult::kSuccess) |
| return false; |
| |
| // TODO(crbug/1261685): While it's not immediately obvious, |client_state| is |
| // not used for successfully loaded safe seeds that are rejected after |
| // additional validation (expiry and future milestone). |
| client_state->reference_date = |
| local_state_->GetTime(prefs::kVariationsSafeSeedDate); |
| client_state->locale = |
| local_state_->GetString(prefs::kVariationsSafeSeedLocale); |
| client_state->permanent_consistency_country = local_state_->GetString( |
| prefs::kVariationsSafeSeedPermanentConsistencyCountry); |
| client_state->session_consistency_country = local_state_->GetString( |
| prefs::kVariationsSafeSeedSessionConsistencyCountry); |
| return true; |
| } |
| |
| bool VariationsSeedStore::StoreSafeSeed( |
| const std::string& seed_data, |
| const std::string& base64_seed_signature, |
| int seed_milestone, |
| const ClientFilterableState& client_state, |
| base::Time seed_fetch_time) { |
| std::string base64_seed_data; |
| ValidatedSeed seed; |
| StoreSeedResult validation_result = ValidateSeedBytes( |
| seed_data, base64_seed_signature, SeedType::SAFE, &seed); |
| if (validation_result != StoreSeedResult::kSuccess) { |
| RecordStoreSafeSeedResult(validation_result); |
| return false; |
| } |
| |
| StoreSeedResult result = StoreValidatedSafeSeed( |
| seed, seed_milestone, client_state, seed_fetch_time); |
| RecordStoreSafeSeedResult(result); |
| return result == StoreSeedResult::kSuccess; |
| } |
| |
| base::Time VariationsSeedStore::GetLastFetchTime() const { |
| return local_state_->GetTime(prefs::kVariationsLastFetchTime); |
| } |
| |
| base::Time VariationsSeedStore::GetSafeSeedFetchTime() const { |
| return local_state_->GetTime(prefs::kVariationsSafeSeedFetchTime); |
| } |
| |
| void VariationsSeedStore::RecordLastFetchTime(base::Time fetch_time) { |
| local_state_->SetTime(prefs::kVariationsLastFetchTime, fetch_time); |
| |
| // If the latest and safe seeds are identical, update the fetch time for the |
| // safe seed as well. |
| if (local_state_->GetString(prefs::kVariationsCompressedSeed) == |
| kIdenticalToSafeSeedSentinel) { |
| local_state_->SetTime(prefs::kVariationsSafeSeedFetchTime, fetch_time); |
| } |
| } |
| |
| void VariationsSeedStore::UpdateSeedDateAndLogDayChange( |
| const base::Time& server_date_fetched) { |
| UpdateSeedDateResult result = UpdateSeedDateResult::NO_OLD_DATE; |
| |
| if (local_state_->HasPrefPath(prefs::kVariationsSeedDate)) { |
| const base::Time stored_date = |
| local_state_->GetTime(prefs::kVariationsSeedDate); |
| result = GetSeedDateChangeState(server_date_fetched, stored_date); |
| } |
| |
| UMA_HISTOGRAM_ENUMERATION("Variations.SeedDateChange", result, |
| UpdateSeedDateResult::ENUM_SIZE); |
| |
| local_state_->SetTime(prefs::kVariationsSeedDate, server_date_fetched); |
| } |
| |
| const std::string& VariationsSeedStore::GetLatestSerialNumber() { |
| if (latest_serial_number_.empty()) { |
| // Efficiency note: This code should rarely be reached; typically, the |
| // latest serial number should be cached via the call to LoadSeed(). The |
| // call to ParseFromString() can be expensive, so it's best to only perform |
| // it once, if possible: [ https://crbug.com/761684#c2 ]. At the time of |
| // this writing, the only expected code path that should reach this code is |
| // when running in safe mode. |
| std::string seed_data; |
| VariationsSeed seed; |
| if (ReadSeedData(SeedType::LATEST, &seed_data) == |
| LoadSeedResult::kSuccess && |
| seed.ParseFromString(seed_data)) { |
| latest_serial_number_ = seed.serial_number(); |
| } |
| } |
| return latest_serial_number_; |
| } |
| |
| // static |
| void VariationsSeedStore::RegisterPrefs(PrefRegistrySimple* registry) { |
| // Regular seed prefs: |
| registry->RegisterStringPref(prefs::kVariationsCompressedSeed, std::string()); |
| registry->RegisterStringPref(prefs::kVariationsCountry, std::string()); |
| registry->RegisterTimePref(prefs::kVariationsLastFetchTime, base::Time()); |
| registry->RegisterIntegerPref(prefs::kVariationsSeedMilestone, 0); |
| registry->RegisterTimePref(prefs::kVariationsSeedDate, base::Time()); |
| registry->RegisterStringPref(prefs::kVariationsSeedSignature, std::string()); |
| |
| // Safe seed prefs: |
| registry->RegisterStringPref(prefs::kVariationsSafeCompressedSeed, |
| std::string()); |
| registry->RegisterTimePref(prefs::kVariationsSafeSeedDate, base::Time()); |
| registry->RegisterTimePref(prefs::kVariationsSafeSeedFetchTime, base::Time()); |
| registry->RegisterStringPref(prefs::kVariationsSafeSeedLocale, std::string()); |
| registry->RegisterIntegerPref(prefs::kVariationsSafeSeedMilestone, 0); |
| registry->RegisterStringPref( |
| prefs::kVariationsSafeSeedPermanentConsistencyCountry, std::string()); |
| registry->RegisterStringPref( |
| prefs::kVariationsSafeSeedSessionConsistencyCountry, std::string()); |
| registry->RegisterStringPref(prefs::kVariationsSafeSeedSignature, |
| std::string()); |
| } |
| |
| // static |
| VerifySignatureResult VariationsSeedStore::VerifySeedSignatureForTesting( |
| const std::string& seed_bytes, |
| const std::string& base64_seed_signature) { |
| return VerifySeedSignature(seed_bytes, base64_seed_signature); |
| } |
| |
| // It is intentional that country-related prefs are retained for regular seeds |
| // and cleared for safe seeds. |
| // |
| // For regular seeds, the prefs are kept for two reasons. First, it's better to |
| // have some idea of a country recently associated with the device. Second, some |
| // past, country-gated launches started relying on the VariationsService- |
| // provided country when they retired server-side configs. |
| // |
| // The safe seed prefs are needed to correctly apply a safe seed, so if the safe |
| // seed is cleared, there's no reason to retain them as they may be incorrect |
| // for the next safe seed. |
| void VariationsSeedStore::ClearPrefs(SeedType seed_type) { |
| if (seed_type == SeedType::LATEST) { |
| local_state_->ClearPref(prefs::kVariationsCompressedSeed); |
| local_state_->ClearPref(prefs::kVariationsLastFetchTime); |
| local_state_->ClearPref(prefs::kVariationsSeedDate); |
| local_state_->ClearPref(prefs::kVariationsSeedSignature); |
| return; |
| } |
| |
| DCHECK_EQ(seed_type, SeedType::SAFE); |
| local_state_->ClearPref(prefs::kVariationsSafeCompressedSeed); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedDate); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedFetchTime); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedLocale); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedMilestone); |
| local_state_->ClearPref( |
| prefs::kVariationsSafeSeedPermanentConsistencyCountry); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedSessionConsistencyCountry); |
| local_state_->ClearPref(prefs::kVariationsSafeSeedSignature); |
| } |
| |
| #if BUILDFLAG(IS_ANDROID) |
| void VariationsSeedStore::ImportInitialSeed( |
| std::unique_ptr<SeedResponse> initial_seed) { |
| if (initial_seed->data.empty()) { |
| // Note: This is an expected case on non-first run starts. |
| RecordFirstRunSeedImportResult( |
| FirstRunSeedImportResult::FAIL_NO_FIRST_RUN_SEED); |
| return; |
| } |
| |
| // Clear the Java-side seed prefs. At this point, the seed has |
| // already been fetched from the Java side, so it's no longer |
| // needed there. This is done regardless if we fail or succeed |
| // below - since if we succeed, we're good to go and if we fail, |
| // we probably don't want to keep around the bad content anyway. |
| if (use_first_run_prefs_) { |
| android::ClearJavaFirstRunPrefs(); |
| } |
| |
| if (initial_seed->date == 0) { |
| RecordFirstRunSeedImportResult( |
| FirstRunSeedImportResult::FAIL_INVALID_RESPONSE_DATE); |
| LOG(WARNING) << "Missing response date"; |
| return; |
| } |
| base::Time date = base::Time::FromJavaTime(initial_seed->date); |
| |
| if (!StoreSeedData(initial_seed->data, initial_seed->signature, |
| initial_seed->country, date, false, |
| initial_seed->is_gzip_compressed, nullptr)) { |
| RecordFirstRunSeedImportResult(FirstRunSeedImportResult::FAIL_STORE_FAILED); |
| LOG(WARNING) << "First run variations seed is invalid."; |
| return; |
| } |
| RecordFirstRunSeedImportResult(FirstRunSeedImportResult::SUCCESS); |
| } |
| #endif // BUILDFLAG(IS_ANDROID) |
| |
| LoadSeedResult VariationsSeedStore::LoadSeedImpl( |
| SeedType seed_type, |
| VariationsSeed* seed, |
| std::string* seed_data, |
| std::string* base64_seed_signature) { |
| LoadSeedResult read_result = ReadSeedData(seed_type, seed_data); |
| if (read_result != LoadSeedResult::kSuccess) |
| return read_result; |
| |
| *base64_seed_signature = local_state_->GetString( |
| seed_type == SeedType::LATEST ? prefs::kVariationsSeedSignature |
| : prefs::kVariationsSafeSeedSignature); |
| if (signature_verification_enabled_) { |
| const VerifySignatureResult result = |
| VerifySeedSignature(*seed_data, *base64_seed_signature); |
| if (seed_type == SeedType::LATEST) { |
| UMA_HISTOGRAM_ENUMERATION("Variations.LoadSeedSignature", result, |
| VerifySignatureResult::ENUM_SIZE); |
| } else { |
| UMA_HISTOGRAM_ENUMERATION( |
| "Variations.SafeMode.LoadSafeSeed.SignatureValidity", result, |
| VerifySignatureResult::ENUM_SIZE); |
| } |
| if (result != VerifySignatureResult::VALID_SIGNATURE) { |
| ClearPrefs(seed_type); |
| return LoadSeedResult::kInvalidSignature; |
| } |
| } |
| |
| if (!seed->ParseFromString(*seed_data)) { |
| ClearPrefs(seed_type); |
| return LoadSeedResult::kCorruptProtobuf; |
| } |
| |
| return LoadSeedResult::kSuccess; |
| } |
| |
| LoadSeedResult VariationsSeedStore::ReadSeedData(SeedType seed_type, |
| std::string* seed_data) { |
| std::string base64_seed_data = local_state_->GetString( |
| seed_type == SeedType::LATEST ? prefs::kVariationsCompressedSeed |
| : prefs::kVariationsSafeCompressedSeed); |
| if (base64_seed_data.empty()) |
| return LoadSeedResult::kEmpty; |
| |
| // As a space optimization, the latest seed might not be stored directly, but |
| // rather aliased to the safe seed. |
| if (seed_type == SeedType::LATEST && |
| base64_seed_data == kIdenticalToSafeSeedSentinel) { |
| return ReadSeedData(SeedType::SAFE, seed_data); |
| } |
| |
| // If the decode process fails, assume the pref value is corrupt and clear it. |
| std::string decoded_data; |
| if (!base::Base64Decode(base64_seed_data, &decoded_data)) { |
| ClearPrefs(seed_type); |
| return LoadSeedResult::kCorruptBase64; |
| } |
| |
| if (!compression::GzipUncompress(decoded_data, seed_data)) { |
| ClearPrefs(seed_type); |
| return LoadSeedResult::kCorruptGzip; |
| } |
| |
| return LoadSeedResult::kSuccess; |
| } |
| |
| StoreSeedResult VariationsSeedStore::ResolveDelta( |
| const std::string& delta_bytes, |
| std::string* seed_bytes) { |
| DCHECK(seed_bytes); |
| std::string existing_seed_bytes; |
| LoadSeedResult read_result = |
| ReadSeedData(SeedType::LATEST, &existing_seed_bytes); |
| if (read_result != LoadSeedResult::kSuccess) |
| return StoreSeedResult::kFailedDeltaReadSeed; |
| if (!ApplyDeltaPatch(existing_seed_bytes, delta_bytes, seed_bytes)) |
| return StoreSeedResult::kFailedDeltaApply; |
| return StoreSeedResult::kSuccess; |
| } |
| |
| StoreSeedResult VariationsSeedStore::ResolveInstanceManipulations( |
| const std::string& data, |
| const InstanceManipulations& im, |
| std::string* seed_bytes) { |
| DCHECK(seed_bytes); |
| // If the data is gzip compressed, first uncompress it. |
| std::string ungzipped_data; |
| if (im.gzip_compressed) { |
| StoreSeedResult result = Uncompress(data, &ungzipped_data); |
| if (result != StoreSeedResult::kSuccess) |
| return result; |
| } else { |
| ungzipped_data = data; |
| } |
| |
| if (!im.delta_compressed) { |
| seed_bytes->swap(ungzipped_data); |
| return StoreSeedResult::kSuccess; |
| } |
| |
| return ResolveDelta(ungzipped_data, seed_bytes); |
| } |
| |
| StoreSeedResult VariationsSeedStore::ValidateSeedBytes( |
| const std::string& seed_bytes, |
| const std::string& base64_seed_signature, |
| SeedType seed_type, |
| ValidatedSeed* result) { |
| DCHECK(result); |
| if (seed_bytes.empty()) |
| return StoreSeedResult::kFailedEmptyGzipContents; |
| |
| // Only store the seed data if it parses correctly. |
| VariationsSeed seed; |
| if (!seed.ParseFromString(seed_bytes)) |
| return StoreSeedResult::kFailedParse; |
| |
| if (signature_verification_enabled_) { |
| const VerifySignatureResult verify_result = |
| VerifySeedSignature(seed_bytes, base64_seed_signature); |
| switch (seed_type) { |
| case SeedType::LATEST: |
| UMA_HISTOGRAM_ENUMERATION("Variations.StoreSeedSignature", |
| verify_result, |
| VerifySignatureResult::ENUM_SIZE); |
| break; |
| case SeedType::SAFE: |
| UMA_HISTOGRAM_ENUMERATION( |
| "Variations.SafeMode.StoreSafeSeed.SignatureValidity", |
| verify_result, VerifySignatureResult::ENUM_SIZE); |
| break; |
| } |
| |
| if (verify_result != VerifySignatureResult::VALID_SIGNATURE) |
| return StoreSeedResult::kFailedSignature; |
| } |
| result->bytes = seed_bytes; |
| result->base64_seed_signature = base64_seed_signature; |
| result->parsed.Swap(&seed); |
| return StoreSeedResult::kSuccess; |
| } |
| |
| StoreSeedResult VariationsSeedStore::CompressSeedBytes( |
| const ValidatedSeed& seed, |
| std::string* base64_seed_data) { |
| // Compress the seed before base64-encoding and storing. |
| std::string compressed_seed_data; |
| if (!compression::GzipCompress(seed.bytes, &compressed_seed_data)) |
| return StoreSeedResult::kFailedGzip; |
| |
| base::Base64Encode(compressed_seed_data, base64_seed_data); |
| return StoreSeedResult::kSuccess; |
| } |
| |
| StoreSeedResult VariationsSeedStore::StoreValidatedSeed( |
| const ValidatedSeed& seed, |
| const std::string& country_code, |
| const base::Time& date_fetched) { |
| std::string base64_seed_data; |
| StoreSeedResult result = CompressSeedBytes(seed, &base64_seed_data); |
| if (result != StoreSeedResult::kSuccess) |
| return result; |
| #if BUILDFLAG(IS_ANDROID) |
| // If currently we do not have any stored pref then we mark seed storing as |
| // successful on the Java side to avoid repeated seed fetches. |
| if (local_state_->GetString(prefs::kVariationsCompressedSeed).empty() && |
| use_first_run_prefs_) { |
| android::MarkVariationsSeedAsStored(); |
| } |
| #endif |
| |
| // Update the saved country code only if one was returned from the server. |
| if (!country_code.empty()) |
| local_state_->SetString(prefs::kVariationsCountry, country_code); |
| |
| int milestone; |
| if (base::StringToInt(version_info::GetMajorVersionNumber(), &milestone)) |
| local_state_->SetInteger(prefs::kVariationsSeedMilestone, milestone); |
| |
| // As a space optimization, store an alias to the safe seed if the contents |
| // are identical. |
| bool matches_safe_seed = |
| (base64_seed_data == |
| local_state_->GetString(prefs::kVariationsSafeCompressedSeed)); |
| local_state_->SetString( |
| prefs::kVariationsCompressedSeed, |
| matches_safe_seed ? kIdenticalToSafeSeedSentinel : base64_seed_data); |
| |
| UpdateSeedDateAndLogDayChange(date_fetched); |
| local_state_->SetString(prefs::kVariationsSeedSignature, |
| seed.base64_seed_signature); |
| latest_serial_number_ = seed.parsed.serial_number(); |
| return StoreSeedResult::kSuccess; |
| } |
| |
| StoreSeedResult VariationsSeedStore::StoreValidatedSafeSeed( |
| const ValidatedSeed& seed, |
| int seed_milestone, |
| const ClientFilterableState& client_state, |
| base::Time seed_fetch_time) { |
| std::string base64_seed_data; |
| StoreSeedResult result = CompressSeedBytes(seed, &base64_seed_data); |
| if (result != StoreSeedResult::kSuccess) |
| return result; |
| // As a performance optimization, avoid an expensive no-op of overwriting |
| // the previous safe seed with an identical copy. |
| std::string previous_safe_seed = |
| local_state_->GetString(prefs::kVariationsSafeCompressedSeed); |
| if (base64_seed_data != previous_safe_seed) { |
| // It's theoretically possible to overwrite an existing safe seed value, |
| // which was identical to the latest seed, with a new value. This could |
| // happen, for example, if: |
| // (1) Seed A is received from the server and saved as both the safe and |
| // latest seed value. |
| // (2) Seed B is received from the server and saved as the latest seed |
| // value. |
| // (3) The user restarts Chrome, which is now running with the |
| // configuration from seed B. |
| // (4) Seed A is received again from the server, perhaps due to a |
| // rollback. |
| // In this situation, seed A should be saved as the latest seed, while |
| // seed B should be saved as the safe seed, i.e. the previously saved |
| // values should be swapped. Indeed, it is guaranteed that the latest seed |
| // value should be overwritten in this case, as a seed should not be |
| // considered safe unless a new seed can be both received *and saved* from |
| // the server. |
| std::string latest_seed = |
| local_state_->GetString(prefs::kVariationsCompressedSeed); |
| if (latest_seed == kIdenticalToSafeSeedSentinel) { |
| local_state_->SetString(prefs::kVariationsCompressedSeed, |
| previous_safe_seed); |
| } |
| local_state_->SetString(prefs::kVariationsSafeCompressedSeed, |
| base64_seed_data); |
| } |
| |
| local_state_->SetString(prefs::kVariationsSafeSeedSignature, |
| seed.base64_seed_signature); |
| local_state_->SetTime(prefs::kVariationsSafeSeedDate, |
| client_state.reference_date); |
| local_state_->SetString(prefs::kVariationsSafeSeedLocale, |
| client_state.locale); |
| local_state_->SetInteger(prefs::kVariationsSafeSeedMilestone, seed_milestone); |
| local_state_->SetString(prefs::kVariationsSafeSeedPermanentConsistencyCountry, |
| client_state.permanent_consistency_country); |
| local_state_->SetString(prefs::kVariationsSafeSeedSessionConsistencyCountry, |
| client_state.session_consistency_country); |
| |
| // As a space optimization, overwrite the stored latest seed data with an |
| // alias to the safe seed, if they are identical. |
| if (base64_seed_data == |
| local_state_->GetString(prefs::kVariationsCompressedSeed)) { |
| local_state_->SetString(prefs::kVariationsCompressedSeed, |
| kIdenticalToSafeSeedSentinel); |
| |
| // Moreover, in this case, the last fetch time for the safe seed should |
| // match the latest seed's. |
| seed_fetch_time = GetLastFetchTime(); |
| } |
| local_state_->SetTime(prefs::kVariationsSafeSeedFetchTime, seed_fetch_time); |
| |
| return StoreSeedResult::kSuccess; |
| } |
| |
| // static |
| bool VariationsSeedStore::ApplyDeltaPatch(const std::string& existing_data, |
| const std::string& patch, |
| std::string* output) { |
| output->clear(); |
| |
| google::protobuf::io::CodedInputStream in( |
| reinterpret_cast<const uint8_t*>(patch.data()), patch.length()); |
| // Temporary string declared outside the loop so it can be re-used between |
| // different iterations (rather than allocating new ones). |
| std::string temp; |
| |
| const uint32_t existing_data_size = |
| static_cast<uint32_t>(existing_data.size()); |
| while (in.CurrentPosition() != static_cast<int>(patch.length())) { |
| uint32_t value; |
| if (!in.ReadVarint32(&value)) |
| return false; |
| |
| if (value != 0) { |
| // A non-zero value indicates the number of bytes to copy from the patch |
| // stream to the output. |
| |
| // No need to guard against bad data (i.e. very large |value|) because the |
| // call below will fail if |value| is greater than the size of the patch. |
| if (!in.ReadString(&temp, value)) |
| return false; |
| output->append(temp); |
| } else { |
| // Otherwise, when it's zero, it indicates that it's followed by a pair of |
| // numbers - |offset| and |length| that specify a range of data to copy |
| // from |existing_data|. |
| uint32_t offset; |
| uint32_t length; |
| if (!in.ReadVarint32(&offset) || !in.ReadVarint32(&length)) |
| return false; |
| |
| // Check for |offset + length| being out of range and for overflow. |
| base::CheckedNumeric<uint32_t> end_offset(offset); |
| end_offset += length; |
| if (!end_offset.IsValid() || end_offset.ValueOrDie() > existing_data_size) |
| return false; |
| output->append(existing_data, offset, length); |
| } |
| } |
| return true; |
| } |
| |
| } // namespace variations |
