gecko-dev/toolkit/components/url-classifier/LookupCache.cpp

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C++

//* -*- 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 "LookupCache.h"
#include "HashStore.h"
#include "nsISeekableStream.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Logging.h"
#include "nsNetUtil.h"
#include "prprf.h"
#include "Classifier.h"
#include "nsUrlClassifierInfo.h"
// We act as the main entry point for all the real lookups,
// so note that those are not done to the actual HashStore.
// The latter solely exists to store the data needed to handle
// the updates from the protocol.
// This module provides a front for PrefixSet, mUpdateCompletions,
// and mGetHashCache, which together contain everything needed to
// provide a classification as long as the data is up to date.
// PrefixSet stores and provides lookups for 4-byte prefixes.
// mUpdateCompletions contains 32-byte completions which were
// contained in updates. They are retrieved from HashStore/.sbtore
// on startup.
// mGetHashCache contains 32-byte completions which were
// returned from the gethash server. They are not serialized,
// only cached until the next update.
// Name of the persistent PrefixSet storage
#define PREFIXSET_SUFFIX ".pset"
#define V2_CACHE_DURATION_SEC (15 * 60)
// 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)
namespace mozilla {
namespace safebrowsing {
const int CacheResultV2::VER = CacheResult::V2;
const int CacheResultV4::VER = CacheResult::V4;
const int LookupCacheV2::VER = 2;
static
void CStringToHexString(const nsACString& aIn, nsACString& aOut)
{
static const char* const lut = "0123456789ABCDEF";
size_t len = aIn.Length();
MOZ_ASSERT(len <= COMPLETE_SIZE);
aOut.SetCapacity(2 * len);
for (size_t i = 0; i < aIn.Length(); ++i) {
const char c = static_cast<char>(aIn[i]);
aOut.Append(lut[(c >> 4) & 0x0F]);
aOut.Append(lut[c & 15]);
}
}
LookupCache::LookupCache(const nsACString& aTableName,
const nsACString& aProvider,
nsIFile* aRootStoreDir)
: mPrimed(false)
, mTableName(aTableName)
, mProvider(aProvider)
, mRootStoreDirectory(aRootStoreDir)
{
UpdateRootDirHandle(mRootStoreDirectory);
}
nsresult
LookupCache::Open()
{
LOG(("Loading PrefixSet for %s", mTableName.get()));
nsresult rv = LoadPrefixSet();
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult
LookupCache::UpdateRootDirHandle(nsIFile* aNewRootStoreDirectory)
{
nsresult rv;
if (aNewRootStoreDirectory != mRootStoreDirectory) {
rv = aNewRootStoreDirectory->Clone(getter_AddRefs(mRootStoreDirectory));
NS_ENSURE_SUCCESS(rv, rv);
}
rv = Classifier::GetPrivateStoreDirectory(mRootStoreDirectory,
mTableName,
mProvider,
getter_AddRefs(mStoreDirectory));
if (NS_FAILED(rv)) {
LOG(("Failed to get private store directory for %s", mTableName.get()));
mStoreDirectory = mRootStoreDirectory;
}
if (LOG_ENABLED()) {
nsString path;
mStoreDirectory->GetPath(path);
LOG(("Private store directory for %s is %s", mTableName.get(),
NS_ConvertUTF16toUTF8(path).get()));
}
return rv;
}
nsresult
LookupCache::WriteFile()
{
if (nsUrlClassifierDBService::ShutdownHasStarted()) {
return NS_ERROR_ABORT;
}
nsCOMPtr<nsIFile> psFile;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(psFile));
NS_ENSURE_SUCCESS(rv, rv);
rv = psFile->AppendNative(mTableName + NS_LITERAL_CSTRING(PREFIXSET_SUFFIX));
NS_ENSURE_SUCCESS(rv, rv);
rv = StoreToFile(psFile);
NS_WARNING_ASSERTION(NS_SUCCEEDED(rv), "failed to store the prefixset");
return NS_OK;
}
nsresult
LookupCache::CheckCache(const Completion& aCompletion,
bool* aHas,
bool* aConfirmed)
{
// Shouldn't call this function if prefix is not in the database.
MOZ_ASSERT(*aHas);
*aConfirmed = false;
uint32_t prefix = aCompletion.ToUint32();
CachedFullHashResponse* fullHashResponse = mFullHashCache.Get(prefix);
if (!fullHashResponse) {
return NS_OK;
}
int64_t nowSec = PR_Now() / PR_USEC_PER_SEC;
int64_t expiryTimeSec;
FullHashExpiryCache& fullHashes = fullHashResponse->fullHashes;
nsDependentCSubstring completion(
reinterpret_cast<const char*>(aCompletion.buf), COMPLETE_SIZE);
// Check if we can find the fullhash in positive cache
if (fullHashes.Get(completion, &expiryTimeSec)) {
if (nowSec <= expiryTimeSec) {
// Url is NOT safe.
*aConfirmed = true;
LOG(("Found a valid fullhash in the positive cache"));
} else {
// Trigger a gethash request in this case(aConfirmed is false).
LOG(("Found an expired fullhash in the positive cache"));
// Remove fullhash entry from the cache when the negative cache
// is also expired because whether or not the fullhash is cached
// locally, we will need to consult the server next time we
// lookup this hash. We may as well remove it from our cache.
if (fullHashResponse->negativeCacheExpirySec < expiryTimeSec) {
fullHashes.Remove(completion);
if (fullHashes.Count() == 0 &&
fullHashResponse->negativeCacheExpirySec < nowSec) {
mFullHashCache.Remove(prefix);
}
}
}
return NS_OK;
}
// Check negative cache.
if (fullHashResponse->negativeCacheExpirySec >= nowSec) {
// Url is safe.
LOG(("Found a valid prefix in the negative cache"));
*aHas = false;
} else {
LOG(("Found an expired prefix in the negative cache"));
if (fullHashes.Count() == 0) {
mFullHashCache.Remove(prefix);
}
}
return NS_OK;
}
// This function remove cache entries whose negative cache time is expired.
// It is possible that a cache entry whose positive cache time is not yet
// expired but still being removed after calling this API. Right now we call
// this on every update.
void
LookupCache::InvalidateExpiredCacheEntries()
{
int64_t nowSec = PR_Now() / PR_USEC_PER_SEC;
for (auto iter = mFullHashCache.Iter(); !iter.Done(); iter.Next()) {
CachedFullHashResponse* response = iter.Data();
if (response->negativeCacheExpirySec < nowSec) {
iter.Remove();
}
}
}
void
LookupCache::CopyFullHashCache(const LookupCache* aSource)
{
if (!aSource) {
return;
}
CopyClassHashTable<FullHashResponseMap>(aSource->mFullHashCache,
mFullHashCache);
}
void
LookupCache::ClearCache()
{
mFullHashCache.Clear();
}
void
LookupCache::ClearAll()
{
ClearCache();
ClearPrefixes();
mPrimed = false;
}
void
LookupCache::GetCacheInfo(nsIUrlClassifierCacheInfo** aCache)
{
MOZ_ASSERT(aCache);
RefPtr<nsUrlClassifierCacheInfo> info = new nsUrlClassifierCacheInfo;
info->table = mTableName;
for (auto iter = mFullHashCache.ConstIter(); !iter.Done(); iter.Next()) {
RefPtr<nsUrlClassifierCacheEntry> entry = new nsUrlClassifierCacheEntry;
// Set prefix of the cache entry.
nsAutoCString prefix(reinterpret_cast<const char*>(&iter.Key()), PREFIX_SIZE);
CStringToHexString(prefix, entry->prefix);
// Set expiry of the cache entry.
CachedFullHashResponse* response = iter.Data();
entry->expirySec = response->negativeCacheExpirySec;
// Set positive cache.
FullHashExpiryCache& fullHashes = response->fullHashes;
for (auto iter2 = fullHashes.ConstIter(); !iter2.Done(); iter2.Next()) {
RefPtr<nsUrlClassifierPositiveCacheEntry> match =
new nsUrlClassifierPositiveCacheEntry;
// Set fullhash of positive cache entry.
CStringToHexString(iter2.Key(), match->fullhash);
// Set expiry of positive cache entry.
match->expirySec = iter2.Data();
entry->matches.AppendElement(
static_cast<nsIUrlClassifierPositiveCacheEntry*>(match));
}
info->entries.AppendElement(static_cast<nsIUrlClassifierCacheEntry*>(entry));
}
NS_ADDREF(*aCache = info);
}
/* static */ bool
LookupCache::IsCanonicalizedIP(const nsACString& aHost)
{
// The canonicalization process will have left IP addresses in dotted
// decimal with no surprises.
uint32_t i1, i2, i3, i4;
char c;
if (PR_sscanf(PromiseFlatCString(aHost).get(), "%u.%u.%u.%u%c",
&i1, &i2, &i3, &i4, &c) == 4) {
return (i1 <= 0xFF && i2 <= 0xFF && i3 <= 0xFF && i4 <= 0xFF);
}
return false;
}
/* static */ nsresult
LookupCache::GetLookupFragments(const nsACString& aSpec,
nsTArray<nsCString>* aFragments)
{
aFragments->Clear();
nsACString::const_iterator begin, end, iter;
aSpec.BeginReading(begin);
aSpec.EndReading(end);
iter = begin;
if (!FindCharInReadable('/', iter, end)) {
return NS_OK;
}
const nsACString& host = Substring(begin, iter++);
nsAutoCString path;
path.Assign(Substring(iter, end));
/**
* From the protocol doc:
* For the hostname, the client will try at most 5 different strings. They
* are:
* a) The exact hostname of the url
* b) The 4 hostnames formed by starting with the last 5 components and
* successivly removing the leading component. The top-level component
* can be skipped. This is not done if the hostname is a numerical IP.
*/
nsTArray<nsCString> hosts;
hosts.AppendElement(host);
if (!IsCanonicalizedIP(host)) {
host.BeginReading(begin);
host.EndReading(end);
int numHostComponents = 0;
while (RFindInReadable(NS_LITERAL_CSTRING("."), begin, end) &&
numHostComponents < MAX_HOST_COMPONENTS) {
// don't bother checking toplevel domains
if (++numHostComponents >= 2) {
host.EndReading(iter);
hosts.AppendElement(Substring(end, iter));
}
end = begin;
host.BeginReading(begin);
}
}
/**
* From the protocol doc:
* For the path, the client will also try at most 6 different strings.
* They are:
* a) the exact path of the url, including query parameters
* b) the exact path of the url, without query parameters
* c) the 4 paths formed by starting at the root (/) and
* successively appending path components, including a trailing
* slash. This behavior should only extend up to the next-to-last
* path component, that is, a trailing slash should never be
* appended that was not present in the original url.
*/
nsTArray<nsCString> paths;
nsAutoCString pathToAdd;
path.BeginReading(begin);
path.EndReading(end);
iter = begin;
if (FindCharInReadable('?', iter, end)) {
pathToAdd = Substring(begin, iter);
paths.AppendElement(pathToAdd);
end = iter;
}
int numPathComponents = 1;
iter = begin;
while (FindCharInReadable('/', iter, end) &&
numPathComponents < MAX_PATH_COMPONENTS) {
iter++;
pathToAdd.Assign(Substring(begin, iter));
paths.AppendElement(pathToAdd);
numPathComponents++;
}
// If we haven't already done so, add the full path
if (!pathToAdd.Equals(path)) {
paths.AppendElement(path);
}
// Check an empty path (for whole-domain blacklist entries)
paths.AppendElement(EmptyCString());
for (uint32_t hostIndex = 0; hostIndex < hosts.Length(); hostIndex++) {
for (uint32_t pathIndex = 0; pathIndex < paths.Length(); pathIndex++) {
nsCString key;
key.Assign(hosts[hostIndex]);
key.Append('/');
key.Append(paths[pathIndex]);
LOG(("Checking fragment %s", key.get()));
aFragments->AppendElement(key);
}
}
return NS_OK;
}
/* static */ nsresult
LookupCache::GetHostKeys(const nsACString& aSpec,
nsTArray<nsCString>* aHostKeys)
{
nsACString::const_iterator begin, end, iter;
aSpec.BeginReading(begin);
aSpec.EndReading(end);
iter = begin;
if (!FindCharInReadable('/', iter, end)) {
return NS_OK;
}
const nsACString& host = Substring(begin, iter);
if (IsCanonicalizedIP(host)) {
nsCString *key = aHostKeys->AppendElement();
if (!key)
return NS_ERROR_OUT_OF_MEMORY;
key->Assign(host);
key->AppendLiteral("/");
return NS_OK;
}
nsTArray<nsCString> hostComponents;
ParseString(PromiseFlatCString(host), '.', hostComponents);
if (hostComponents.Length() < 2) {
// no host or toplevel host, this won't match anything in the db
return NS_OK;
}
// First check with two domain components
int32_t last = int32_t(hostComponents.Length()) - 1;
nsCString *lookupHost = aHostKeys->AppendElement();
if (!lookupHost)
return NS_ERROR_OUT_OF_MEMORY;
lookupHost->Assign(hostComponents[last - 1]);
lookupHost->AppendLiteral(".");
lookupHost->Append(hostComponents[last]);
lookupHost->AppendLiteral("/");
// Now check with three domain components
if (hostComponents.Length() > 2) {
nsCString *lookupHost2 = aHostKeys->AppendElement();
if (!lookupHost2)
return NS_ERROR_OUT_OF_MEMORY;
lookupHost2->Assign(hostComponents[last - 2]);
lookupHost2->AppendLiteral(".");
lookupHost2->Append(*lookupHost);
}
return NS_OK;
}
nsresult
LookupCache::LoadPrefixSet()
{
nsCOMPtr<nsIFile> psFile;
nsresult rv = mStoreDirectory->Clone(getter_AddRefs(psFile));
NS_ENSURE_SUCCESS(rv, rv);
rv = psFile->AppendNative(mTableName + NS_LITERAL_CSTRING(PREFIXSET_SUFFIX));
NS_ENSURE_SUCCESS(rv, rv);
bool exists;
rv = psFile->Exists(&exists);
NS_ENSURE_SUCCESS(rv, rv);
if (exists) {
LOG(("stored PrefixSet exists, loading from disk"));
rv = LoadFromFile(psFile);
if (NS_FAILED(rv)) {
return rv;
}
mPrimed = true;
} else {
LOG(("no (usable) stored PrefixSet found"));
}
#ifdef DEBUG
if (mPrimed) {
uint32_t size = SizeOfPrefixSet();
LOG(("SB tree done, size = %d bytes\n", size));
}
#endif
return NS_OK;
}
#if defined(DEBUG)
static
nsCString GetFormattedTimeString(int64_t aCurTimeSec)
{
PRExplodedTime pret;
PR_ExplodeTime(aCurTimeSec * PR_USEC_PER_SEC, PR_GMTParameters, &pret);
return nsPrintfCString(
"%04d-%02d-%02d %02d:%02d:%02d UTC",
pret.tm_year, pret.tm_month + 1, pret.tm_mday,
pret.tm_hour, pret.tm_min, pret.tm_sec);
}
void
LookupCache::DumpCache()
{
if (!LOG_ENABLED()) {
return;
}
for (auto iter = mFullHashCache.ConstIter(); !iter.Done(); iter.Next()) {
CachedFullHashResponse* response = iter.Data();
nsAutoCString prefix;
CStringToHexString(
nsCString(reinterpret_cast<const char*>(&iter.Key()), PREFIX_SIZE), prefix);
LOG(("Cache prefix(%s): %s, Expiry: %s", mTableName.get(), prefix.get(),
GetFormattedTimeString(response->negativeCacheExpirySec).get()));
FullHashExpiryCache& fullHashes = response->fullHashes;
for (auto iter2 = fullHashes.ConstIter(); !iter2.Done(); iter2.Next()) {
nsAutoCString fullhash;
CStringToHexString(iter2.Key(), fullhash);
LOG((" - %s, Expiry: %s", fullhash.get(),
GetFormattedTimeString(iter2.Data()).get()));
}
}
}
#endif
nsresult
LookupCacheV2::Init()
{
mPrefixSet = new nsUrlClassifierPrefixSet();
nsresult rv = mPrefixSet->Init(mTableName);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult
LookupCacheV2::Open()
{
nsresult rv = LookupCache::Open();
NS_ENSURE_SUCCESS(rv, rv);
LOG(("Reading Completions"));
rv = ReadCompletions();
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
void
LookupCacheV2::ClearAll()
{
LookupCache::ClearAll();
mUpdateCompletions.Clear();
}
nsresult
LookupCacheV2::Has(const Completion& aCompletion,
bool* aHas,
uint32_t* aMatchLength,
bool* aConfirmed)
{
*aHas = *aConfirmed = false;
*aMatchLength = 0;
uint32_t prefix = aCompletion.ToUint32();
bool found;
nsresult rv = mPrefixSet->Contains(prefix, &found);
NS_ENSURE_SUCCESS(rv, rv);
if (found) {
*aHas = true;
*aMatchLength = PREFIX_SIZE;
} else if (mUpdateCompletions.ContainsSorted(aCompletion)) {
// Completions is found in database, confirm the result
*aHas = true;
*aMatchLength = COMPLETE_SIZE;
*aConfirmed = true;
}
if (*aHas && !(*aConfirmed)) {
rv = CheckCache(aCompletion, aHas, aConfirmed);
}
LOG(("Probe in %s: %X, has %d, confirmed %d",
mTableName.get(), prefix, *aHas, *aConfirmed));
return rv;
}
bool
LookupCacheV2::IsEmpty()
{
bool isEmpty;
mPrefixSet->IsEmpty(&isEmpty);
return isEmpty;
}
nsresult
LookupCacheV2::Build(AddPrefixArray& aAddPrefixes,
AddCompleteArray& aAddCompletes)
{
Telemetry::Accumulate(Telemetry::URLCLASSIFIER_LC_COMPLETIONS,
static_cast<uint32_t>(aAddCompletes.Length()));
mUpdateCompletions.Clear();
if (!mUpdateCompletions.SetCapacity(aAddCompletes.Length(), fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
for (uint32_t i = 0; i < aAddCompletes.Length(); i++) {
mUpdateCompletions.AppendElement(aAddCompletes[i].CompleteHash());
}
aAddCompletes.Clear();
mUpdateCompletions.Sort();
Telemetry::Accumulate(Telemetry::URLCLASSIFIER_LC_PREFIXES,
static_cast<uint32_t>(aAddPrefixes.Length()));
nsresult rv = ConstructPrefixSet(aAddPrefixes);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult
LookupCacheV2::GetPrefixes(FallibleTArray<uint32_t>& aAddPrefixes)
{
if (!mPrimed) {
// This can happen if its a new table, so no error.
LOG(("GetPrefixes from empty LookupCache"));
return NS_OK;
}
return mPrefixSet->GetPrefixesNative(aAddPrefixes);
}
void
LookupCacheV2::AddGethashResultToCache(AddCompleteArray& aAddCompletes,
MissPrefixArray& aMissPrefixes,
int64_t aExpirySec)
{
int64_t defaultExpirySec = PR_Now() / PR_USEC_PER_SEC + V2_CACHE_DURATION_SEC;
if (aExpirySec != 0) {
defaultExpirySec = aExpirySec;
}
for (const AddComplete& add : aAddCompletes) {
nsDependentCSubstring fullhash(
reinterpret_cast<const char*>(add.CompleteHash().buf), COMPLETE_SIZE);
CachedFullHashResponse* response =
mFullHashCache.LookupOrAdd(add.ToUint32());
response->negativeCacheExpirySec = defaultExpirySec;
FullHashExpiryCache& fullHashes = response->fullHashes;
fullHashes.Put(fullhash, defaultExpirySec);
}
for (const Prefix& prefix : aMissPrefixes) {
CachedFullHashResponse* response =
mFullHashCache.LookupOrAdd(prefix.ToUint32());
response->negativeCacheExpirySec = defaultExpirySec;
}
}
nsresult
LookupCacheV2::ReadCompletions()
{
HashStore store(mTableName, mProvider, mRootStoreDirectory);
nsresult rv = store.Open();
NS_ENSURE_SUCCESS(rv, rv);
mUpdateCompletions.Clear();
const AddCompleteArray& addComplete = store.AddCompletes();
if (!mUpdateCompletions.SetCapacity(addComplete.Length(), fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
for (uint32_t i = 0; i < addComplete.Length(); i++) {
mUpdateCompletions.AppendElement(addComplete[i].complete);
}
return NS_OK;
}
nsresult
LookupCacheV2::ClearPrefixes()
{
return mPrefixSet->SetPrefixes(nullptr, 0);
}
nsresult
LookupCacheV2::StoreToFile(nsIFile* aFile)
{
return mPrefixSet->StoreToFile(aFile);
}
nsresult
LookupCacheV2::LoadFromFile(nsIFile* aFile)
{
return mPrefixSet->LoadFromFile(aFile);
}
size_t
LookupCacheV2::SizeOfPrefixSet()
{
return mPrefixSet->SizeOfIncludingThis(moz_malloc_size_of);
}
#ifdef DEBUG
template <class T>
static void EnsureSorted(T* aArray)
{
typename T::elem_type* start = aArray->Elements();
typename T::elem_type* end = aArray->Elements() + aArray->Length();
typename T::elem_type* iter = start;
typename T::elem_type* previous = start;
while (iter != end) {
previous = iter;
++iter;
if (iter != end) {
MOZ_ASSERT(*previous <= *iter);
}
}
return;
}
#endif
nsresult
LookupCacheV2::ConstructPrefixSet(AddPrefixArray& aAddPrefixes)
{
Telemetry::AutoTimer<Telemetry::URLCLASSIFIER_PS_CONSTRUCT_TIME> timer;
nsTArray<uint32_t> array;
if (!array.SetCapacity(aAddPrefixes.Length(), fallible)) {
return NS_ERROR_OUT_OF_MEMORY;
}
for (uint32_t i = 0; i < aAddPrefixes.Length(); i++) {
array.AppendElement(aAddPrefixes[i].PrefixHash().ToUint32());
}
aAddPrefixes.Clear();
#ifdef DEBUG
// PrefixSet requires sorted order
EnsureSorted(&array);
#endif
// construct new one, replace old entries
nsresult rv = mPrefixSet->SetPrefixes(array.Elements(), array.Length());
NS_ENSURE_SUCCESS(rv, rv);
#ifdef DEBUG
uint32_t size;
size = mPrefixSet->SizeOfIncludingThis(moz_malloc_size_of);
LOG(("SB tree done, size = %d bytes\n", size));
#endif
mPrimed = true;
return NS_OK;
}
#if defined(DEBUG)
void
LookupCacheV2::DumpCompletions()
{
if (!LOG_ENABLED())
return;
for (uint32_t i = 0; i < mUpdateCompletions.Length(); i++) {
nsAutoCString str;
mUpdateCompletions[i].ToHexString(str);
LOG(("Update: %s", str.get()));
}
}
#endif
} // namespace safebrowsing
} // namespace mozilla