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/**
* TLS Stateless Session Manager for stateless servers
* (C) 2023 Jack Lloyd
* 2023 René Meusel - Rohde & Schwarz Cybersecurity
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/tls_session_manager_stateless.h>
#include <botan/credentials_manager.h>
#include <botan/exceptn.h>
#include <botan/rng.h>
#include <botan/internal/stl_util.h>
namespace Botan::TLS {
Session_Manager_Stateless::Session_Manager_Stateless(const std::shared_ptr<Credentials_Manager>& creds,
const std::shared_ptr<RandomNumberGenerator>& rng) :
Session_Manager(rng), m_credentials_manager(creds) {
BOTAN_ASSERT_NONNULL(m_credentials_manager);
}
std::optional<Session_Handle> Session_Manager_Stateless::establish(const Session& session,
const std::optional<Session_ID>&,
bool tls12_no_ticket) {
BOTAN_ASSERT(session.side() == Connection_Side::Server, "Client tried to establish a session");
if(tls12_no_ticket) {
return std::nullopt;
}
const auto key = get_ticket_key();
if(!key.has_value()) {
return std::nullopt;
}
return Session_Ticket{session.encrypt(key.value(), *m_rng)};
}
void Session_Manager_Stateless::store(const Session&, const Session_Handle&) {
throw Invalid_Argument("A stateless Session Manager cannot store Sessions with their handle");
}
std::optional<Session> Session_Manager_Stateless::retrieve_one(const Session_Handle& handle) {
auto ticket = handle.ticket();
if(!ticket.has_value()) {
return std::nullopt;
}
const auto key = get_ticket_key();
if(!key.has_value()) {
return std::nullopt;
}
try {
return Session::decrypt(ticket.value(), key.value());
} catch(const std::exception&) {
// RFC 8446 4.2.11
// Any unknown PSKs (e.g., ones not in the PSK database or encrypted
// with an unknown key) SHOULD simply be ignored.
return std::nullopt;
}
}
bool Session_Manager_Stateless::emits_session_tickets() {
return get_ticket_key().has_value();
}
std::optional<SymmetricKey> Session_Manager_Stateless::get_ticket_key() noexcept {
try {
auto key = m_credentials_manager->psk("tls-server", "session-ticket", "");
if(key.empty()) {
return std::nullopt;
}
return key;
} catch(...) {
return std::nullopt;
}
}
} // namespace Botan::TLS