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//* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "LookupCacheV4.h"
#include "HashStore.h"
#include "mozilla/Unused.h"
#include "nsCheckSummedOutputStream.h"
#include "crc32c.h"
#include <string>
// MOZ_LOG=UrlClassifierDbService:5
extern mozilla::LazyLogModule gUrlClassifierDbServiceLog;
#define LOG(args) \
MOZ_LOG(gUrlClassifierDbServiceLog, mozilla::LogLevel::Debug, args)
#define LOG_ENABLED() \
MOZ_LOG_TEST(gUrlClassifierDbServiceLog, mozilla::LogLevel::Debug)
#define METADATA_SUFFIX ".metadata"_ns
namespace mozilla {
namespace safebrowsing {
const int LookupCacheV4::VER = 4;
const uint32_t LookupCacheV4::VLPSET_MAGIC = 0x36044a35;
const uint32_t LookupCacheV4::VLPSET_VERSION = 1;
const uint32_t LookupCacheV4::MAX_METADATA_VALUE_LENGTH = 256;
////////////////////////////////////////////////////////////////////////
// Prefixes coming from updates and VLPrefixSet are both stored in the HashTable
// where the (key, value) pair is a prefix size and a lexicographic-sorted
// string. The difference is prefixes from updates use std:string(to avoid
// additional copies) and prefixes from VLPrefixSet use nsCString. This class
// provides a common interface for the partial update algorithm to make it
// easier to operate on two different kind prefix string map..
class VLPrefixSet {
public:
explicit VLPrefixSet(const PrefixStringMap& aMap);
// This function will merge the prefix map in VLPrefixSet to aPrefixMap.
void Merge(PrefixStringMap& aPrefixMap);
// Find the smallest string from the map in VLPrefixSet.
bool GetSmallestPrefix(nsACString& aOutString) const;
// Return the number of prefixes in the map
uint32_t Count() const { return mCount; }
private:
// PrefixString structure contains a lexicographic-sorted string with
// a |pos| variable to indicate which substring we are pointing to right now.
// |pos| increases each time GetSmallestPrefix finds the smallest string.
struct PrefixString {
PrefixString(const nsACString& aStr, uint32_t aSize)
: data(aStr), pos(0), size(aSize) {
MOZ_ASSERT(data.Length() % size == 0,
"PrefixString length must be a multiple of the prefix size.");
}
void getRemainingString(nsACString& out) {
MOZ_ASSERT(out.IsEmpty());
if (remaining() > 0) {
out = Substring(data, pos);
}
}
void getPrefix(nsACString& out) {
MOZ_ASSERT(out.IsEmpty());
if (remaining() >= size) {
out = Substring(data, pos, size);
} else {
MOZ_ASSERT(remaining() == 0,
"Remaining bytes but not enough for a (size)-byte prefix.");
}
}
void next() {
pos += size;
MOZ_ASSERT(pos <= data.Length());
}
uint32_t remaining() {
return data.Length() - pos;
MOZ_ASSERT(pos <= data.Length());
}
nsCString data;
uint32_t pos;
uint32_t size;
};
nsClassHashtable<nsUint32HashKey, PrefixString> mMap;
uint32_t mCount;
};
nsresult LookupCacheV4::Has(const Completion& aCompletion, bool* aHas,
uint32_t* aMatchLength, bool* aConfirmed) {
*aHas = *aConfirmed = false;
*aMatchLength = 0;
uint32_t length = 0;
nsDependentCSubstring fullhash;
fullhash.Rebind((const char*)aCompletion.buf, COMPLETE_SIZE);
// It is tricky that we use BigEndian read for V4 while use
// Completion.ToUint32 for V2. This is because in V2, prefixes are converted
// to integers and then sorted internally. In V4, prefixes recieved are
// already lexicographical order sorted, so when we manipulate these prefixes
// with integer form, we always use big endian so prefixes remain the same
// order.
uint32_t prefix = BigEndian::readUint32(
reinterpret_cast<const uint32_t*>(fullhash.BeginReading()));
nsresult rv = mVLPrefixSet->Matches(prefix, fullhash, &length);
NS_ENSURE_SUCCESS(rv, rv);
if (length == 0) {
return NS_OK;
}
MOZ_ASSERT(length >= PREFIX_SIZE && length <= COMPLETE_SIZE);
// For V4, We don't set |aConfirmed| to true even if we found a match
// for 32-bytes prefix. |aConfirmed| is only set if a match is found in cache.
*aHas = true;
*aMatchLength = length;
// Even though V4 supports variable-length prefix, we always send 4-bytes for
// completion (Bug 1323953). This means cached prefix length is also 4-bytes.
return CheckCache(aCompletion, aHas, aConfirmed);
}
nsresult LookupCacheV4::Build(PrefixStringMap& aPrefixMap) {
Telemetry::AutoTimer<Telemetry::URLCLASSIFIER_VLPS_CONSTRUCT_TIME> timer;
nsresult rv = mVLPrefixSet->SetPrefixes(aPrefixMap);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
mPrimed = true;
return NS_OK;
}
nsresult LookupCacheV4::GetPrefixes(PrefixStringMap& aPrefixMap) {
if (!mPrimed) {
// This can happen if its a new table, so no error.
LOG(("GetPrefixes from empty LookupCache"));
return NS_OK;
}
return mVLPrefixSet->GetPrefixes(aPrefixMap);
}
nsresult LookupCacheV4::GetFixedLengthPrefixes(
FallibleTArray<uint32_t>& aPrefixes) {
return mVLPrefixSet->GetFixedLengthPrefixes(&aPrefixes, nullptr);
}
nsresult LookupCacheV4::ClearLegacyFile() {
nsCOMPtr<nsIFile> file;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(file));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
rv = file->AppendNative(mTableName + ".pset"_ns);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
bool exists;
rv = file->Exists(&exists);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
if (exists) {
rv = file->Remove(false);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
LOG(("[%s] Old PrefixSet is successfully removed!", mTableName.get()));
}
return NS_OK;
}
nsresult LookupCacheV4::LoadLegacyFile() {
nsCOMPtr<nsIFile> file;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(file));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
rv = file->AppendNative(mTableName + ".pset"_ns);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
bool exists;
rv = file->Exists(&exists);
NS_ENSURE_SUCCESS(rv, rv);
if (!exists) {
return NS_ERROR_FAILURE;
}
nsCOMPtr<nsIInputStream> localInFile;
rv = NS_NewLocalFileInputStream(getter_AddRefs(localInFile), file,
PR_RDONLY | nsIFile::OS_READAHEAD);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
// Calculate how big the file is, make sure our read buffer isn't bigger
// than the file itself which is just wasting memory.
int64_t fileSize;
rv = file->GetFileSize(&fileSize);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
if (fileSize < 0 || fileSize > UINT32_MAX) {
return NS_ERROR_FAILURE;
}
uint32_t bufferSize =
std::min<uint32_t>(static_cast<uint32_t>(fileSize), MAX_BUFFER_SIZE);
// Convert to buffered stream
nsCOMPtr<nsIInputStream> in;
rv = NS_NewBufferedInputStream(getter_AddRefs(in), localInFile.forget(),
bufferSize);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
// Load data
rv = mVLPrefixSet->LoadPrefixes(in);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
mPrimed = true;
LOG(("[%s] Loading Legacy PrefixSet successful", mTableName.get()));
return NS_OK;
}
void LookupCacheV4::GetHeader(Header& aHeader) {
aHeader.magic = LookupCacheV4::VLPSET_MAGIC;
aHeader.version = LookupCacheV4::VLPSET_VERSION;
}
nsresult LookupCacheV4::SanityCheck(const Header& aHeader) {
if (aHeader.magic != LookupCacheV4::VLPSET_MAGIC) {
return NS_ERROR_FILE_CORRUPTED;
}
if (aHeader.version != LookupCacheV4::VLPSET_VERSION) {
return NS_ERROR_FAILURE;
}
return NS_OK;
}
nsCString LookupCacheV4::GetPrefixSetSuffix() const { return ".vlpset"_ns; }
static nsresult AppendPrefixToMap(PrefixStringMap& prefixes,
const nsACString& prefix) {
uint32_t len = prefix.Length();
MOZ_ASSERT(len >= PREFIX_SIZE && len <= COMPLETE_SIZE);
if (!len) {
return NS_OK;
}
nsCString* prefixString = prefixes.GetOrInsertNew(len);
if (!prefixString->Append(prefix, fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
return NS_OK;
}
static nsresult InitCrypto(nsCOMPtr<nsICryptoHash>& aCrypto) {
nsresult rv;
aCrypto = do_CreateInstance(NS_CRYPTO_HASH_CONTRACTID, &rv);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
rv = aCrypto->Init(nsICryptoHash::SHA256);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "InitCrypto failed");
return rv;
}
// Read prefix into a buffer and also update the hash which
// keeps track of the sha256 hash
static void UpdateSHA256(nsICryptoHash* aCrypto, const nsACString& aPrefix) {
MOZ_ASSERT(aCrypto);
aCrypto->Update(
reinterpret_cast<uint8_t*>(const_cast<char*>(aPrefix.BeginReading())),
aPrefix.Length());
}
// Please see https://bug1287058.bmoattachments.org/attachment.cgi?id=8795366
// for detail about partial update algorithm.
nsresult LookupCacheV4::ApplyUpdate(RefPtr<TableUpdateV4> aTableUpdate,
PrefixStringMap& aInputMap,
PrefixStringMap& aOutputMap) {
MOZ_ASSERT(aOutputMap.IsEmpty());
nsCOMPtr<nsICryptoHash> crypto;
nsresult rv = InitCrypto(crypto);
if (NS_FAILED(rv)) {
return rv;
}
// oldPSet contains prefixes we already have or we just merged last round.
// addPSet contains prefixes stored in tableUpdate which should be merged with
// oldPSet.
VLPrefixSet oldPSet(aInputMap);
VLPrefixSet addPSet(aTableUpdate->Prefixes());
// RemovalIndiceArray is a sorted integer array indicating the index of prefix
// we should remove from the old prefix set(according to lexigraphic order).
// |removalIndex| is the current index of RemovalIndiceArray.
// |numOldPrefixPicked| is used to record how many prefixes we picked from the
// old map.
const TableUpdateV4::RemovalIndiceArray& removalArray =
aTableUpdate->RemovalIndices();
uint32_t removalIndex = 0;
int32_t numOldPrefixPicked = -1;
nsAutoCString smallestOldPrefix;
nsAutoCString smallestAddPrefix;
bool isOldMapEmpty = false, isAddMapEmpty = false;
// This is used to avoid infinite loop for partial update algorithm.
// The maximum loops will be the number of old prefixes plus the number of add
// prefixes.
int32_t index = oldPSet.Count() + addPSet.Count() + 1;
for (; index > 0; index--) {
// Get smallest prefix from the old prefix set if we don't have one
if (smallestOldPrefix.IsEmpty() && !isOldMapEmpty) {
isOldMapEmpty = !oldPSet.GetSmallestPrefix(smallestOldPrefix);
}
// Get smallest prefix from add prefix set if we don't have one
if (smallestAddPrefix.IsEmpty() && !isAddMapEmpty) {
isAddMapEmpty = !addPSet.GetSmallestPrefix(smallestAddPrefix);
}
bool pickOld;
// If both prefix sets are not empty, then compare to find the smaller one.
if (!isOldMapEmpty && !isAddMapEmpty) {
if (smallestOldPrefix == smallestAddPrefix) {
LOG(("Add prefix should not exist in the original prefix set."));
return NS_ERROR_UC_UPDATE_DUPLICATE_PREFIX;
}
// Compare the smallest string in old prefix set and add prefix set,
// merge the smaller one into new map to ensure merged string still
// follows lexigraphic order.
pickOld = smallestOldPrefix < smallestAddPrefix;
} else if (!isOldMapEmpty && isAddMapEmpty) {
pickOld = true;
} else if (isOldMapEmpty && !isAddMapEmpty) {
pickOld = false;
// If both maps are empty, then partial update is complete.
} else {
break;
}
if (pickOld) {
numOldPrefixPicked++;
// If the number of picks from old map matches the removalIndex, then this
// prefix will be removed by not merging it to new map.
if (removalIndex < removalArray.Length() &&
numOldPrefixPicked == removalArray[removalIndex]) {
removalIndex++;
} else {
rv = AppendPrefixToMap(aOutputMap, smallestOldPrefix);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
UpdateSHA256(crypto, smallestOldPrefix);
}
smallestOldPrefix.SetLength(0);
} else {
rv = AppendPrefixToMap(aOutputMap, smallestAddPrefix);
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
UpdateSHA256(crypto, smallestAddPrefix);
smallestAddPrefix.SetLength(0);
}
}
// We expect index will be greater to 0 because max number of runs will be
// the number of original prefix plus add prefix.
if (index <= 0) {
LOG(("There are still prefixes remaining after reaching maximum runs."));
return NS_ERROR_UC_UPDATE_INFINITE_LOOP;
}
if (removalIndex < removalArray.Length()) {
LOG(
("There are still prefixes to remove after exhausting the old "
"PrefixSet."));
return NS_ERROR_UC_UPDATE_WRONG_REMOVAL_INDICES;
}
// Prefixes and removal indice from update is no longer required
// after merging the data with local prefixes.
aTableUpdate->Clear();
nsAutoCString sha256;
crypto->Finish(false, sha256);
if (aTableUpdate->SHA256().IsEmpty()) {
LOG(("Update sha256 hash missing."));
Telemetry::Accumulate(
Telemetry::URLCLASSIFIER_UPDATE_ERROR, mProvider,
NS_ERROR_GET_CODE(NS_ERROR_UC_UPDATE_MISSING_CHECKSUM));
// Generate our own sha256 to tableUpdate to ensure there is always
// checksum in .metadata
std::string stdSha256(sha256.BeginReading(), sha256.Length());
aTableUpdate->SetSHA256(stdSha256);
} else if (aTableUpdate->SHA256() != sha256) {
LOG(("SHA256 hash mismatch after applying partial update"));
return NS_ERROR_UC_UPDATE_CHECKSUM_MISMATCH;
}
return NS_OK;
}
nsresult LookupCacheV4::AddFullHashResponseToCache(
const FullHashResponseMap& aResponseMap) {
CopyClassHashTable<FullHashResponseMap>(aResponseMap, mFullHashCache);
return NS_OK;
}
nsresult LookupCacheV4::WriteMetadata(
RefPtr<const TableUpdateV4> aTableUpdate) {
NS_ENSURE_ARG_POINTER(aTableUpdate);
if (nsUrlClassifierDBService::ShutdownHasStarted()) {
return NS_ERROR_ABORT;
}
nsCOMPtr<nsIFile> metaFile;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(metaFile));
NS_ENSURE_SUCCESS(rv, rv);
rv = metaFile->AppendNative(mTableName + METADATA_SUFFIX);
NS_ENSURE_SUCCESS(rv, rv);
nsCOMPtr<nsIOutputStream> outputStream;
rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), metaFile,
PR_WRONLY | PR_TRUNCATE | PR_CREATE_FILE);
NS_ENSURE_SUCCESS(rv, rv);
// Write the state.
rv = WriteValue(outputStream, aTableUpdate->ClientState());
NS_ENSURE_SUCCESS(rv, rv);
// Write the SHA256 hash.
rv = WriteValue(outputStream, aTableUpdate->SHA256());
NS_ENSURE_SUCCESS(rv, rv);
return rv;
}
nsresult LookupCacheV4::LoadMetadata(nsACString& aState, nsACString& aSHA256) {
nsCOMPtr<nsIFile> metaFile;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(metaFile));
NS_ENSURE_SUCCESS(rv, rv);
rv = metaFile->AppendNative(mTableName + METADATA_SUFFIX);
NS_ENSURE_SUCCESS(rv, rv);
nsCOMPtr<nsIInputStream> localInFile;
rv = NS_NewLocalFileInputStream(getter_AddRefs(localInFile), metaFile,
PR_RDONLY | nsIFile::OS_READAHEAD);
if (NS_FAILED(rv)) {
LOG(("Unable to open metadata file."));
return rv;
}
// Read the list state.
rv = ReadValue(localInFile, aState);
if (NS_FAILED(rv)) {
LOG(("Failed to read state."));
return rv;
}
// Read the SHA256 hash.
rv = ReadValue(localInFile, aSHA256);
if (NS_FAILED(rv)) {
LOG(("Failed to read SHA256 hash."));
return rv;
}
return rv;
}
VLPrefixSet::VLPrefixSet(const PrefixStringMap& aMap) : mCount(0) {
for (const auto& entry : aMap) {
uint32_t size = entry.GetKey();
MOZ_ASSERT(entry.GetData()->Length() % size == 0,
"PrefixString must be a multiple of the prefix size.");
mMap.InsertOrUpdate(size, MakeUnique<PrefixString>(*entry.GetData(), size));
mCount += entry.GetData()->Length() / size;
}
}
void VLPrefixSet::Merge(PrefixStringMap& aPrefixMap) {
for (const auto& entry : mMap) {
nsCString* prefixString = aPrefixMap.GetOrInsertNew(entry.GetKey());
PrefixString* str = entry.GetWeak();
nsAutoCString remainingString;
str->getRemainingString(remainingString);
if (!remainingString.IsEmpty()) {
MOZ_ASSERT(remainingString.Length() == str->remaining());
prefixString->Append(remainingString);
}
}
}
bool VLPrefixSet::GetSmallestPrefix(nsACString& aOutString) const {
PrefixString* pick = nullptr;
for (const auto& entry : mMap) {
PrefixString* str = entry.GetWeak();
if (str->remaining() <= 0) {
continue;
}
if (aOutString.IsEmpty()) {
str->getPrefix(aOutString);
MOZ_ASSERT(aOutString.Length() == entry.GetKey());
pick = str;
continue;
}
nsAutoCString cur;
str->getPrefix(cur);
if (!cur.IsEmpty() && cur < aOutString) {
aOutString.Assign(cur);
MOZ_ASSERT(aOutString.Length() == entry.GetKey());
pick = str;
}
}
if (pick) {
pick->next();
}
return pick != nullptr;
}
nsresult LookupCacheV4::LoadMozEntries() { return NS_ERROR_NOT_IMPLEMENTED; }
} // namespace safebrowsing
} // namespace mozilla