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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/ssl/ssl_client_session_cache.h"
#include <tuple>
#include <utility>
#include "base/containers/flat_set.h"
#include "base/time/clock.h"
#include "base/time/default_clock.h"
#include "third_party/boringssl/src/include/openssl/ssl.h"
namespace net {
namespace {
// Returns a tuple of references to fields of |key|, for comparison purposes.
auto TieKeyFields(const SSLClientSessionCache::Key& key) {
return std::tie(key.server, key.dest_ip_addr, key.network_anonymization_key,
key.privacy_mode, key.disable_legacy_crypto);
}
} // namespace
SSLClientSessionCache::Key::Key() = default;
SSLClientSessionCache::Key::Key(const Key& other) = default;
SSLClientSessionCache::Key::Key(Key&& other) = default;
SSLClientSessionCache::Key::~Key() = default;
SSLClientSessionCache::Key& SSLClientSessionCache::Key::operator=(
const Key& other) = default;
SSLClientSessionCache::Key& SSLClientSessionCache::Key::operator=(Key&& other) =
default;
bool SSLClientSessionCache::Key::operator==(const Key& other) const {
return TieKeyFields(*this) == TieKeyFields(other);
}
bool SSLClientSessionCache::Key::operator<(const Key& other) const {
return TieKeyFields(*this) < TieKeyFields(other);
}
SSLClientSessionCache::SSLClientSessionCache(const Config& config)
: clock_(base::DefaultClock::GetInstance()),
config_(config),
cache_(config.max_entries) {
memory_pressure_listener_ = std::make_unique<base::MemoryPressureListener>(
FROM_HERE, base::BindRepeating(&SSLClientSessionCache::OnMemoryPressure,
base::Unretained(this)));
}
SSLClientSessionCache::~SSLClientSessionCache() {
Flush();
}
size_t SSLClientSessionCache::size() const {
return cache_.size();
}
bssl::UniquePtr<SSL_SESSION> SSLClientSessionCache::Lookup(
const Key& cache_key) {
// Expire stale sessions.
lookups_since_flush_++;
if (lookups_since_flush_ >= config_.expiration_check_count) {
lookups_since_flush_ = 0;
FlushExpiredSessions();
}
auto iter = cache_.Get(cache_key);
if (iter == cache_.end())
return nullptr;
time_t now = clock_->Now().ToTimeT();
bssl::UniquePtr<SSL_SESSION> session = iter->second.Pop();
if (iter->second.ExpireSessions(now))
cache_.Erase(iter);
if (IsExpired(session.get(), now))
session = nullptr;
return session;
}
void SSLClientSessionCache::Insert(const Key& cache_key,
bssl::UniquePtr<SSL_SESSION> session) {
auto iter = cache_.Get(cache_key);
if (iter == cache_.end())
iter = cache_.Put(cache_key, Entry());
iter->second.Push(std::move(session));
}
void SSLClientSessionCache::ClearEarlyData(const Key& cache_key) {
auto iter = cache_.Get(cache_key);
if (iter != cache_.end()) {
for (auto& session : iter->second.sessions) {
if (session) {
session.reset(SSL_SESSION_copy_without_early_data(session.get()));
}
}
}
}
void SSLClientSessionCache::FlushForServers(
const base::flat_set<HostPortPair>& servers) {
auto iter = cache_.begin();
while (iter != cache_.end()) {
if (servers.contains(iter->first.server)) {
iter = cache_.Erase(iter);
} else {
++iter;
}
}
}
void SSLClientSessionCache::Flush() {
cache_.Clear();
}
void SSLClientSessionCache::SetClockForTesting(base::Clock* clock) {
clock_ = clock;
}
bool SSLClientSessionCache::IsExpired(SSL_SESSION* session, time_t now) {
if (now < 0)
return true;
uint64_t now_u64 = static_cast<uint64_t>(now);
// now_u64 may be slightly behind because of differences in how
// time is calculated at this layer versus BoringSSL.
// Add a second of wiggle room to account for this.
return now_u64 < SSL_SESSION_get_time(session) - 1 ||
now_u64 >=
SSL_SESSION_get_time(session) + SSL_SESSION_get_timeout(session);
}
SSLClientSessionCache::Entry::Entry() = default;
SSLClientSessionCache::Entry::Entry(Entry&&) = default;
SSLClientSessionCache::Entry::~Entry() = default;
void SSLClientSessionCache::Entry::Push(bssl::UniquePtr<SSL_SESSION> session) {
if (sessions[0] != nullptr &&
SSL_SESSION_should_be_single_use(sessions[0].get())) {
sessions[1] = std::move(sessions[0]);
}
sessions[0] = std::move(session);
}
bssl::UniquePtr<SSL_SESSION> SSLClientSessionCache::Entry::Pop() {
if (sessions[0] == nullptr)
return nullptr;
bssl::UniquePtr<SSL_SESSION> session = bssl::UpRef(sessions[0]);
if (SSL_SESSION_should_be_single_use(session.get())) {
sessions[0] = std::move(sessions[1]);
sessions[1] = nullptr;
}
return session;
}
bool SSLClientSessionCache::Entry::ExpireSessions(time_t now) {
if (sessions[0] == nullptr)
return true;
if (SSLClientSessionCache::IsExpired(sessions[0].get(), now)) {
return true;
}
if (sessions[1] != nullptr &&
SSLClientSessionCache::IsExpired(sessions[1].get(), now)) {
sessions[1] = nullptr;
}
return false;
}
void SSLClientSessionCache::FlushExpiredSessions() {
time_t now = clock_->Now().ToTimeT();
auto iter = cache_.begin();
while (iter != cache_.end()) {
if (iter->second.ExpireSessions(now)) {
iter = cache_.Erase(iter);
} else {
++iter;
}
}
}
void SSLClientSessionCache::OnMemoryPressure(
base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level) {
switch (memory_pressure_level) {
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE:
break;
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE:
FlushExpiredSessions();
break;
case base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL:
Flush();
break;
}
}
} // namespace net
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