21742894084

Committed 06 Feb 2026 07:47AM UTC coverage: 90.073% (+0.003%) from 90.07%

Build # 21742894084

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Commit Message

Merge pull request #5288 from Rohde-Schwarz/feature/disentangle_tls12_from_tls13

Refactor: Organize most TLS handshake messages into TLS 1.2 and TLS 1.3 modules

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94.8

/src/lib/tls/tls_session.cpp

/*
* TLS Session State
* (C) 2011-2012,2015,2019 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/tls_session.h>

#include <botan/aead.h>
#include <botan/asn1_obj.h>
#include <botan/ber_dec.h>
#include <botan/der_enc.h>
#include <botan/mac.h>
#include <botan/pem.h>
#include <botan/rng.h>
#include <botan/tls_callbacks.h>
#include <botan/x509_key.h>
#include <botan/internal/ct_utils.h>
#include <botan/internal/loadstor.h>
#include <botan/internal/stl_util.h>

#if defined(BOTAN_HAS_TLS_13)
   #include <botan/tls_messages_13.h>
#endif

#include <utility>

namespace Botan::TLS {

void Session_Handle::validate_constraints() const {
   std::visit(overloaded{
                 [](const Session_ID& id) {
                    // RFC 5246 7.4.1.2
                    //    opaque SessionID<0..32>;
                    BOTAN_ARG_CHECK(!id.empty(), "Session ID must not be empty");
                    BOTAN_ARG_CHECK(id.size() <= 32, "Session ID cannot be longer than 32 bytes");
                 },
                 [](const Session_Ticket& ticket) {
                    BOTAN_ARG_CHECK(!ticket.empty(), "Ticket most not be empty");
                    BOTAN_ARG_CHECK(ticket.size() <= std::numeric_limits<uint16_t>::max(),
                                    "Ticket cannot be longer than 64kB");
                 },
                 [](const Opaque_Session_Handle& handle) {
                    // RFC 8446 4.6.1
                    //    opaque ticket<1..2^16-1>;
                    BOTAN_ARG_CHECK(!handle.empty(), "Opaque session handle must not be empty");
                    BOTAN_ARG_CHECK(handle.size() <= std::numeric_limits<uint16_t>::max(),
                                    "Opaque session handle cannot be longer than 64kB");
                 },
              },
              m_handle);
}

Opaque_Session_Handle Session_Handle::opaque_handle() const {
   // both a Session_ID and a Session_Ticket could be an Opaque_Session_Handle
   return Opaque_Session_Handle(std::visit([](const auto& handle) { return handle.get(); }, m_handle));
}

std::optional<Session_ID> Session_Handle::id() const {
   if(is_id()) {
      return std::get<Session_ID>(m_handle);
   }

   // Opaque handles can mimic as a Session_ID if they are short enough
   if(is_opaque_handle()) {
      const auto& handle = std::get<Opaque_Session_Handle>(m_handle);
      if(handle.size() <= 32) {
         return Session_ID(handle.get());
      }
   }

   return std::nullopt;
}

std::optional<Session_Ticket> Session_Handle::ticket() const {
   if(is_ticket()) {
      return std::get<Session_Ticket>(m_handle);
   }

   // Opaque handles can mimic 'normal' Session_Tickets at any time
   if(is_opaque_handle()) {
      return Session_Ticket(std::get<Opaque_Session_Handle>(m_handle).get());
   }

   return std::nullopt;
}

Ciphersuite Session_Base::ciphersuite() const {
   auto suite = Ciphersuite::by_id(m_ciphersuite);
   if(!suite.has_value()) {
      throw Decoding_Error("Failed to find cipher suite for ID " + std::to_string(m_ciphersuite));
   }
   return suite.value();
}

Session_Summary::Session_Summary(const Session_Base& base,
                                 bool was_resumption,
                                 std::optional<std::string> psk_identity) :
      Session_Base(base), m_external_psk_identity(std::move(psk_identity)), m_was_resumption(was_resumption) {
   BOTAN_ARG_CHECK(version().is_pre_tls_13(), "Instantiated a TLS 1.2 session summary with an newer TLS version");

   const auto cs = ciphersuite();
   m_kex_algo = cs.kex_algo();
}

#if defined(BOTAN_HAS_TLS_13)

namespace {

std::string tls13_kex_to_string(bool psk, std::optional<Named_Group> group) {
   if(psk && group) {
      if(group->is_dh_named_group()) {
         return kex_method_to_string(Kex_Algo::DHE_PSK);
      } else if(group->is_ecdh_named_curve() || group->is_x25519() || group->is_x448()) {
         return kex_method_to_string(Kex_Algo::ECDHE_PSK);
      } else if(group->is_pure_ml_kem() || group->is_pure_frodokem()) {
         return kex_method_to_string(Kex_Algo::KEM_PSK);
      } else if(group->is_pqc_hybrid()) {
         return kex_method_to_string(Kex_Algo::HYBRID_PSK);
      } else if(auto s = group->to_string()) {
         return *s;
      }
   } else if(psk) {
      return kex_method_to_string(Kex_Algo::PSK);
   } else {
      BOTAN_ASSERT_NOMSG(group.has_value());
      if(group->is_dh_named_group()) {
         return kex_method_to_string(Kex_Algo::DH);
      } else if(group->is_ecdh_named_curve() || group->is_x25519() || group->is_x448()) {
         return kex_method_to_string(Kex_Algo::ECDH);
      } else if(group->is_pure_ml_kem() || group->is_pure_frodokem()) {
         return kex_method_to_string(Kex_Algo::KEM);
      } else if(group->is_pqc_hybrid()) {
         return kex_method_to_string(Kex_Algo::HYBRID);
      } else if(auto s = group->to_string()) {
         return *s;
      }
   }

   return kex_method_to_string(Kex_Algo::UNDEFINED);
}

}  // namespace

Session_Summary::Session_Summary(const Server_Hello_13& server_hello,
                                 Connection_Side side,
                                 std::vector<X509_Certificate> peer_certs,
                                 std::shared_ptr<const Public_Key> peer_raw_public_key,
                                 std::optional<std::string> psk_identity,
                                 bool session_was_resumed,
                                 Server_Information server_info,
                                 std::chrono::system_clock::time_point current_timestamp) :
      Session_Base(current_timestamp,
                   server_hello.selected_version(),
                   server_hello.ciphersuite(),
                   side,

                   // TODO: SRTP might become necessary when DTLS 1.3 is being implemented
                   0,

                   // RFC 8446 Appendix D
                   //    Because TLS 1.3 always hashes in the transcript up to the server
                   //    Finished, implementations which support both TLS 1.3 and earlier
                   //    versions SHOULD indicate the use of the Extended Master Secret
                   //    extension in their APIs whenever TLS 1.3 is used.
                   true,

                   // TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
                   false,
                   std::move(peer_certs),
                   std::move(peer_raw_public_key),
                   std::move(server_info)),
      m_external_psk_identity(std::move(psk_identity)),
      m_was_resumption(session_was_resumed) {
   BOTAN_ARG_CHECK(version().is_tls_13_or_later(), "Instantiated a TLS 1.3 session summary with an older TLS version");
   set_session_id(server_hello.session_id());

   // In TLS 1.3 the key exchange algorithm is not negotiated in the ciphersuite
   // anymore. This provides a compatible identifier for applications to use.

   std::optional<Named_Group> group = [&]() -> std::optional<Named_Group> {
      if(psk_used() || was_resumption()) {
         if(auto* const keyshare = server_hello.extensions().get<Key_Share>()) {
            return keyshare->selected_group();
         } else {
            return {};
         }
      } else {
         auto* const keyshare = server_hello.extensions().get<Key_Share>();
         BOTAN_ASSERT_NONNULL(keyshare);
         return keyshare->selected_group();
      }
   }();

   if(group.has_value()) {
      m_kex_parameters = group->to_string();
   }

   m_kex_algo = tls13_kex_to_string(psk_used() || was_resumption(), group);
}

#endif

Session::Session(const secure_vector<uint8_t>& master_secret,
                 Protocol_Version version,
                 uint16_t ciphersuite,
                 Connection_Side side,
                 bool extended_master_secret,
                 bool encrypt_then_mac,
                 const std::vector<X509_Certificate>& certs,
                 const Server_Information& server_info,
                 uint16_t srtp_profile,
                 std::chrono::system_clock::time_point current_timestamp,
                 std::chrono::seconds lifetime_hint) :
      Session_Base(current_timestamp,
                   version,
                   ciphersuite,
                   side,
                   srtp_profile,
                   extended_master_secret,
                   encrypt_then_mac,
                   certs,
                   nullptr,  // RFC 7250 (raw public keys) is NYI for TLS 1.2
                   server_info),
      m_master_secret(master_secret),
      m_early_data_allowed(false),
      m_max_early_data_bytes(0),
      m_ticket_age_add(0),
      m_lifetime_hint(lifetime_hint) {
   BOTAN_ARG_CHECK(version.is_pre_tls_13(), "Instantiated a TLS 1.2 session object with a TLS version newer than 1.2");
}

#if defined(BOTAN_HAS_TLS_13)

Session::Session(const secure_vector<uint8_t>& session_psk,
                 const std::optional<uint32_t>& max_early_data_bytes,
                 uint32_t ticket_age_add,
                 std::chrono::seconds lifetime_hint,
                 Protocol_Version version,
                 uint16_t ciphersuite,
                 Connection_Side side,
                 const std::vector<X509_Certificate>& peer_certs,
                 std::shared_ptr<const Public_Key> peer_raw_public_key,
                 const Server_Information& server_info,
                 std::chrono::system_clock::time_point current_timestamp) :
      Session_Base(current_timestamp,
                   version,
                   ciphersuite,
                   side,

                   // TODO: SRTP might become necessary when DTLS 1.3 is being implemented
                   0,

                   // RFC 8446 Appendix D
                   //    Because TLS 1.3 always hashes in the transcript up to the server
                   //    Finished, implementations which support both TLS 1.3 and earlier
                   //    versions SHOULD indicate the use of the Extended Master Secret
                   //    extension in their APIs whenever TLS 1.3 is used.
                   true,

                   // TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
                   false,
                   peer_certs,
                   std::move(peer_raw_public_key),
                   server_info),
      m_master_secret(session_psk),
      m_early_data_allowed(max_early_data_bytes.has_value()),
      m_max_early_data_bytes(max_early_data_bytes.value_or(0)),
      m_ticket_age_add(ticket_age_add),
      m_lifetime_hint(lifetime_hint) {
   BOTAN_ARG_CHECK(!version.is_pre_tls_13(), "Instantiated a TLS 1.3 session object with a TLS version older than 1.3");
}

Session::Session(secure_vector<uint8_t>&& session_psk,
                 const std::optional<uint32_t>& max_early_data_bytes,
                 std::chrono::seconds lifetime_hint,
                 const std::vector<X509_Certificate>& peer_certs,
                 std::shared_ptr<const Public_Key> peer_raw_public_key,
                 const Client_Hello_13& client_hello,
                 const Server_Hello_13& server_hello,
                 Callbacks& callbacks,
                 RandomNumberGenerator& rng) :
      Session_Base(callbacks.tls_current_timestamp(),
                   server_hello.selected_version(),
                   server_hello.ciphersuite(),
                   Connection_Side::Server,
                   0,
                   true,
                   false,  // see constructor above for rationales
                   peer_certs,
                   std::move(peer_raw_public_key),
                   Server_Information(client_hello.sni_hostname())),
      m_master_secret(std::move(session_psk)),
      m_early_data_allowed(max_early_data_bytes.has_value()),
      m_max_early_data_bytes(max_early_data_bytes.value_or(0)),
      m_ticket_age_add(load_be<uint32_t>(rng.random_vec(4).data(), 0)),
      m_lifetime_hint(lifetime_hint) {
   BOTAN_ARG_CHECK(!m_version.is_pre_tls_13(),
                   "Instantiated a TLS 1.3 session object with a TLS version older than 1.3");
}

#endif

Session::Session(std::string_view pem) : Session(PEM_Code::decode_check_label(pem, "TLS SESSION")) {}

Session::Session(std::span<const uint8_t> ber_data) /* NOLINT(*-member-init) */ {
   uint8_t side_code = 0;

   std::vector<uint8_t> raw_pubkey_or_empty;

   ASN1_String server_hostname;
   ASN1_String server_service;
   size_t server_port = 0;

   uint8_t major_version = 0;
   uint8_t minor_version = 0;

   size_t start_time = 0;
   size_t srtp_profile = 0;
   uint16_t ciphersuite_code = 0;
   uint64_t lifetime_hint = 0;

   BER_Decoder(ber_data.data(), ber_data.size())
      .start_sequence()
      .decode_and_check(TLS_SESSION_PARAM_STRUCT_VERSION, "Unknown version in serialized TLS session")
      .decode_integer_type(start_time)
      .decode_integer_type(major_version)
      .decode_integer_type(minor_version)
      .decode_integer_type(ciphersuite_code)
      .decode_integer_type(side_code)
      .decode(m_extended_master_secret)
      .decode(m_encrypt_then_mac)
      .decode(m_master_secret, ASN1_Type::OctetString)
      .decode_list<X509_Certificate>(m_peer_certs)
      .decode(raw_pubkey_or_empty, ASN1_Type::OctetString)
      .decode(server_hostname)
      .decode(server_service)
      .decode(server_port)
      .decode(srtp_profile)
      .decode(m_early_data_allowed)
      .decode_integer_type(m_max_early_data_bytes)
      .decode_integer_type(m_ticket_age_add)
      .decode_integer_type(lifetime_hint)
      .end_cons()
      .verify_end();

   if(!Ciphersuite::by_id(ciphersuite_code)) {
      throw Decoding_Error(
         "Serialized TLS session contains unknown cipher suite "
         "(" +
         std::to_string(ciphersuite_code) + ")");
   }

   m_ciphersuite = ciphersuite_code;
   m_version = Protocol_Version(major_version, minor_version);
   m_start_time = std::chrono::system_clock::from_time_t(start_time);
   m_connection_side = static_cast<Connection_Side>(side_code);
   m_srtp_profile = static_cast<uint16_t>(srtp_profile);

   m_server_info =
      Server_Information(server_hostname.value(), server_service.value(), static_cast<uint16_t>(server_port));

   if(!raw_pubkey_or_empty.empty()) {
      m_peer_raw_public_key = X509::load_key(raw_pubkey_or_empty);
   }

   m_lifetime_hint = std::chrono::seconds(lifetime_hint);
}

secure_vector<uint8_t> Session::DER_encode() const {
   const auto raw_pubkey_or_empty =
      m_peer_raw_public_key ? m_peer_raw_public_key->subject_public_key() : std::vector<uint8_t>{};

   return DER_Encoder()
      .start_sequence()
      .encode(TLS_SESSION_PARAM_STRUCT_VERSION)
      .encode(static_cast<size_t>(std::chrono::system_clock::to_time_t(m_start_time)))
      .encode(static_cast<size_t>(m_version.major_version()))
      .encode(static_cast<size_t>(m_version.minor_version()))
      .encode(static_cast<size_t>(m_ciphersuite))
      .encode(static_cast<size_t>(m_connection_side))
      .encode(m_extended_master_secret)
      .encode(m_encrypt_then_mac)
      .encode(m_master_secret, ASN1_Type::OctetString)
      .start_sequence()
      .encode_list(m_peer_certs)
      .end_cons()
      .encode(raw_pubkey_or_empty, ASN1_Type::OctetString)
      .encode(ASN1_String(m_server_info.hostname(), ASN1_Type::Utf8String))
      .encode(ASN1_String(m_server_info.service(), ASN1_Type::Utf8String))
      .encode(static_cast<size_t>(m_server_info.port()))
      .encode(static_cast<size_t>(m_srtp_profile))

      // the fields below were introduced for TLS 1.3 session tickets
      .encode(m_early_data_allowed)
      .encode(static_cast<size_t>(m_max_early_data_bytes))
      .encode(static_cast<size_t>(m_ticket_age_add))
      .encode(static_cast<size_t>(m_lifetime_hint.count()))
      .end_cons()
      .get_contents();
}

std::string Session::PEM_encode() const {
   return PEM_Code::encode(this->DER_encode(), "TLS SESSION");
}

secure_vector<uint8_t> Session::extract_master_secret() {
   BOTAN_STATE_CHECK(!m_master_secret.empty());
   return std::exchange(m_master_secret, {});
}

namespace {

// The output length of the HMAC must be a valid keylength for the AEAD
const char* const TLS_SESSION_CRYPT_HMAC = "HMAC(SHA-512-256)";
// SIV would be better, but we can't assume it is available
const char* const TLS_SESSION_CRYPT_AEAD = "AES-256/GCM";
const char* const TLS_SESSION_CRYPT_KEY_NAME = "BOTAN TLS SESSION KEY NAME";
const uint64_t TLS_SESSION_CRYPT_MAGIC = 0x068B5A9D396C0000;
const size_t TLS_SESSION_CRYPT_MAGIC_LEN = 8;
const size_t TLS_SESSION_CRYPT_KEY_NAME_LEN = 4;
const size_t TLS_SESSION_CRYPT_AEAD_NONCE_LEN = 12;
const size_t TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN = 16;
const size_t TLS_SESSION_CRYPT_AEAD_TAG_SIZE = 16;

const size_t TLS_SESSION_CRYPT_HDR_LEN = TLS_SESSION_CRYPT_MAGIC_LEN + TLS_SESSION_CRYPT_KEY_NAME_LEN +
                                         TLS_SESSION_CRYPT_AEAD_NONCE_LEN + TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN;

const size_t TLS_SESSION_CRYPT_OVERHEAD = TLS_SESSION_CRYPT_HDR_LEN + TLS_SESSION_CRYPT_AEAD_TAG_SIZE;

}  // namespace

std::vector<uint8_t> Session::encrypt(const SymmetricKey& key, RandomNumberGenerator& rng) const {
   auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);
   hmac->set_key(key);

   // First derive the "key name"
   std::vector<uint8_t> key_name(hmac->output_length());
   hmac->update(TLS_SESSION_CRYPT_KEY_NAME);
   hmac->final(key_name.data());
   key_name.resize(TLS_SESSION_CRYPT_KEY_NAME_LEN);

   std::vector<uint8_t> aead_nonce;
   std::vector<uint8_t> key_seed;

   rng.random_vec(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);
   rng.random_vec(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);

   hmac->update(key_seed);
   const secure_vector<uint8_t> aead_key = hmac->final();

   secure_vector<uint8_t> bits = this->DER_encode();

   // create the header
   std::vector<uint8_t> buf;
   buf.reserve(TLS_SESSION_CRYPT_OVERHEAD + bits.size());
   buf.resize(TLS_SESSION_CRYPT_MAGIC_LEN);
   store_be(TLS_SESSION_CRYPT_MAGIC, &buf[0]);  // NOLINT(*container-data-pointer)
   buf += key_name;
   buf += key_seed;
   buf += aead_nonce;

   auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Encryption);
   BOTAN_ASSERT_NOMSG(aead->valid_nonce_length(TLS_SESSION_CRYPT_AEAD_NONCE_LEN));
   BOTAN_ASSERT_NOMSG(aead->tag_size() == TLS_SESSION_CRYPT_AEAD_TAG_SIZE);
   aead->set_key(aead_key);
   aead->set_associated_data(buf);
   aead->start(aead_nonce);
   aead->finish(bits, 0);

   // append the ciphertext
   buf += bits;
   return buf;
}

Session Session::decrypt(std::span<const uint8_t> in, const SymmetricKey& key) {
   try {
      const size_t min_session_size = 48 + 4;  // serious under-estimate
      if(in.size() < TLS_SESSION_CRYPT_OVERHEAD + min_session_size) {
         throw Decoding_Error("Encrypted session too short to be valid");
      }

      BufferSlicer sub(in);
      const auto* const magic = sub.take(TLS_SESSION_CRYPT_MAGIC_LEN).data();
      const auto* const key_name = sub.take(TLS_SESSION_CRYPT_KEY_NAME_LEN).data();
      const auto* const key_seed = sub.take(TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN).data();
      const auto* const aead_nonce = sub.take(TLS_SESSION_CRYPT_AEAD_NONCE_LEN).data();
      auto ctext = sub.copy_as_secure_vector(sub.remaining());

      if(load_be<uint64_t>(magic, 0) != TLS_SESSION_CRYPT_MAGIC) {
         throw Decoding_Error("Missing expected magic numbers");
      }

      auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);
      hmac->set_key(key);

      // First derive and check the "key name"
      std::vector<uint8_t> cmp_key_name(hmac->output_length());
      hmac->update(TLS_SESSION_CRYPT_KEY_NAME);
      hmac->final(cmp_key_name.data());

      if(CT::is_equal(cmp_key_name.data(), key_name, TLS_SESSION_CRYPT_KEY_NAME_LEN).as_bool() == false) {
         throw Decoding_Error("Wrong key name for encrypted session");
      }

      hmac->update(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);
      const secure_vector<uint8_t> aead_key = hmac->final();

      auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Decryption);
      aead->set_key(aead_key);
      aead->set_associated_data(in.data(), TLS_SESSION_CRYPT_HDR_LEN);
      aead->start(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);
      aead->finish(ctext, 0);
      return Session(ctext);
   } catch(std::exception& e) {
      throw Decoding_Error("Failed to decrypt serialized TLS session: " + std::string(e.what()));
   }
}

}  // namespace Botan::TLS

1	/*
2	* TLS Session State
3	* (C) 2011-2012,2015,2019 Jack Lloyd
4	*
5	* Botan is released under the Simplified BSD License (see license.txt)
6	*/
7
8	#include <botan/tls_session.h>
9
10	#include <botan/aead.h>
11	#include <botan/asn1_obj.h>
12	#include <botan/ber_dec.h>
13	#include <botan/der_enc.h>
14	#include <botan/mac.h>
15	#include <botan/pem.h>
16	#include <botan/rng.h>
17	#include <botan/tls_callbacks.h>
18	#include <botan/x509_key.h>
19	#include <botan/internal/ct_utils.h>
20	#include <botan/internal/loadstor.h>
21	#include <botan/internal/stl_util.h>
22
23	#if defined(BOTAN_HAS_TLS_13)
24	#include <botan/tls_messages_13.h>
25	#endif
26
27	#include <utility>
28
29	namespace Botan::TLS {
30
31	void Session_Handle::validate_constraints() const {	3,551✔
32	std::visit(overloaded{	7,102✔
33	[](const Session_ID& id) {	695✔
34	// RFC 5246 7.4.1.2
35	// opaque SessionID<0..32>;
36	BOTAN_ARG_CHECK(!id.empty(), "Session ID must not be empty");	695✔
37	BOTAN_ARG_CHECK(id.size() <= 32, "Session ID cannot be longer than 32 bytes");	695✔
38	},	695✔
39	[](const Session_Ticket& ticket) {	2,167✔
40	BOTAN_ARG_CHECK(!ticket.empty(), "Ticket most not be empty");	2,167✔
41	BOTAN_ARG_CHECK(ticket.size() <= std::numeric_limits<uint16_t>::max(),	2,167✔
42	"Ticket cannot be longer than 64kB");
43	},	2,167✔
44	[](const Opaque_Session_Handle& handle) {	689✔
45	// RFC 8446 4.6.1
46	// opaque ticket<1..2^16-1>;
47	BOTAN_ARG_CHECK(!handle.empty(), "Opaque session handle must not be empty");	689✔
48	BOTAN_ARG_CHECK(handle.size() <= std::numeric_limits<uint16_t>::max(),	689✔
49	"Opaque session handle cannot be longer than 64kB");
50	},	689✔
51	},
52	m_handle);	3,551✔
53	}	3,551✔
54
55	Opaque_Session_Handle Session_Handle::opaque_handle() const {	367✔
56	// both a Session_ID and a Session_Ticket could be an Opaque_Session_Handle
57	return Opaque_Session_Handle(std::visit([](const auto& handle) { return handle.get(); }, m_handle));	734✔
58	}
59
60	std::optional<Session_ID> Session_Handle::id() const {	2,466✔
61	if(is_id()) {	2,466✔
62	return std::get<Session_ID>(m_handle);	632✔
63	}
64
65	// Opaque handles can mimic as a Session_ID if they are short enough
66	if(is_opaque_handle()) {	1,834✔
67	const auto& handle = std::get<Opaque_Session_Handle>(m_handle);	680✔
68	if(handle.size() <= 32) {	680✔
69	return Session_ID(handle.get());	27✔
70	}
71	}
72
73	return std::nullopt;	1,807✔
74	}
75
76	std::optional<Session_Ticket> Session_Handle::ticket() const {	1,769✔
77	if(is_ticket()) {	1,769✔
78	return std::get<Session_Ticket>(m_handle);	1,220✔
79	}
80
81	// Opaque handles can mimic 'normal' Session_Tickets at any time
82	if(is_opaque_handle()) {	549✔
83	return Session_Ticket(std::get<Opaque_Session_Handle>(m_handle).get());	210✔
84	}
85
86	return std::nullopt;	339✔
87	}
88
89	Ciphersuite Session_Base::ciphersuite() const {	4,908✔
90	auto suite = Ciphersuite::by_id(m_ciphersuite);	4,908✔
91	if(!suite.has_value()) {	4,908✔
92	throw Decoding_Error("Failed to find cipher suite for ID " + std::to_string(m_ciphersuite));	×
93	}
94	return suite.value();	4,908✔
95	}
96
97	Session_Summary::Session_Summary(const Session_Base& base,	1,785✔
98	bool was_resumption,
99	std::optional<std::string> psk_identity) :	1,785✔
100	Session_Base(base), m_external_psk_identity(std::move(psk_identity)), m_was_resumption(was_resumption) {	1,906✔
101	BOTAN_ARG_CHECK(version().is_pre_tls_13(), "Instantiated a TLS 1.2 session summary with an newer TLS version");	1,785✔
102
103	const auto cs = ciphersuite();	1,785✔
104	m_kex_algo = cs.kex_algo();	1,785✔
105	}	1,785✔
106
107	#if defined(BOTAN_HAS_TLS_13)
108
109	namespace {
110
111	std::string tls13_kex_to_string(bool psk, std::optional<Named_Group> group) {	610✔
112	if(psk && group) {	610✔
113	if(group->is_dh_named_group()) {	159✔
114	return kex_method_to_string(Kex_Algo::DHE_PSK);	×
115	} else if(group->is_ecdh_named_curve() \|\| group->is_x25519() \|\| group->is_x448()) {	159✔
116	return kex_method_to_string(Kex_Algo::ECDHE_PSK);	157✔
117	} else if(group->is_pure_ml_kem() \|\| group->is_pure_frodokem()) {	2✔
118	return kex_method_to_string(Kex_Algo::KEM_PSK);	×
119	} else if(group->is_pqc_hybrid()) {	2✔
120	return kex_method_to_string(Kex_Algo::HYBRID_PSK);	2✔
121	} else if(auto s = group->to_string()) {	×
122	return *s;	×
123	}	×
124	} else if(psk) {	451✔
125	return kex_method_to_string(Kex_Algo::PSK);	×
126	} else {
127	BOTAN_ASSERT_NOMSG(group.has_value());	451✔
128	if(group->is_dh_named_group()) {	451✔
129	return kex_method_to_string(Kex_Algo::DH);	×
130	} else if(group->is_ecdh_named_curve() \|\| group->is_x25519() \|\| group->is_x448()) {	451✔
131	return kex_method_to_string(Kex_Algo::ECDH);	419✔
132	} else if(group->is_pure_ml_kem() \|\| group->is_pure_frodokem()) {	32✔
133	return kex_method_to_string(Kex_Algo::KEM);	2✔
134	} else if(group->is_pqc_hybrid()) {	30✔
135	return kex_method_to_string(Kex_Algo::HYBRID);	30✔
136	} else if(auto s = group->to_string()) {	×
137	return *s;	×
138	}	×
139	}
140
141	return kex_method_to_string(Kex_Algo::UNDEFINED);	×
142	}
143
144	} // namespace
145
146	Session_Summary::Session_Summary(const Server_Hello_13& server_hello,	610✔
147	Connection_Side side,
148	std::vector<X509_Certificate> peer_certs,
149	std::shared_ptr<const Public_Key> peer_raw_public_key,
150	std::optional<std::string> psk_identity,
151	bool session_was_resumed,
152	Server_Information server_info,
153	std::chrono::system_clock::time_point current_timestamp) :	610✔
154	Session_Base(current_timestamp,
155	server_hello.selected_version(),
156	server_hello.ciphersuite(),	610✔
157	side,
158
159	// TODO: SRTP might become necessary when DTLS 1.3 is being implemented
160	0,
161
162	// RFC 8446 Appendix D
163	// Because TLS 1.3 always hashes in the transcript up to the server
164	// Finished, implementations which support both TLS 1.3 and earlier
165	// versions SHOULD indicate the use of the Extended Master Secret
166	// extension in their APIs whenever TLS 1.3 is used.
167	true,
168
169	// TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
170	false,
171	std::move(peer_certs),
172	std::move(peer_raw_public_key),
173	std::move(server_info)),
174	m_external_psk_identity(std::move(psk_identity)),	610✔
175	m_was_resumption(session_was_resumed) {	1,834✔
176	BOTAN_ARG_CHECK(version().is_tls_13_or_later(), "Instantiated a TLS 1.3 session summary with an older TLS version");	610✔
177	set_session_id(server_hello.session_id());	1,220✔
178
179	// In TLS 1.3 the key exchange algorithm is not negotiated in the ciphersuite
180	// anymore. This provides a compatible identifier for applications to use.
181
182	std::optional<Named_Group> group = [&]() -> std::optional<Named_Group> {	1,830✔
183	if(psk_used() \|\| was_resumption()) {	610✔
184	if(auto* const keyshare = server_hello.extensions().get<Key_Share>()) {	159✔
185	return keyshare->selected_group();	159✔
186	} else {
187	return {};	×
188	}
189	} else {
190	auto* const keyshare = server_hello.extensions().get<Key_Share>();	451✔
191	BOTAN_ASSERT_NONNULL(keyshare);	451✔
192	return keyshare->selected_group();	451✔
193	}
194	}();	610✔
195
196	if(group.has_value()) {	610✔
197	m_kex_parameters = group->to_string();	1,220✔
198	}
199
200	m_kex_algo = tls13_kex_to_string(psk_used() \|\| was_resumption(), group);	610✔
201	}	610✔
202
203	#endif
204
205	Session::Session(const secure_vector<uint8_t>& master_secret,	1,668✔
206	Protocol_Version version,
207	uint16_t ciphersuite,
208	Connection_Side side,
209	bool extended_master_secret,
210	bool encrypt_then_mac,
211	const std::vector<X509_Certificate>& certs,
212	const Server_Information& server_info,
213	uint16_t srtp_profile,
214	std::chrono::system_clock::time_point current_timestamp,
215	std::chrono::seconds lifetime_hint) :	1,668✔
216	Session_Base(current_timestamp,
217	version,
218	ciphersuite,
219	side,
220	srtp_profile,
221	extended_master_secret,
222	encrypt_then_mac,
223	certs,
224	nullptr, // RFC 7250 (raw public keys) is NYI for TLS 1.2
225	server_info),
226	m_master_secret(master_secret),	1,668✔
227	m_early_data_allowed(false),	1,668✔
228	m_max_early_data_bytes(0),	1,668✔
229	m_ticket_age_add(0),	1,668✔
230	m_lifetime_hint(lifetime_hint) {	3,336✔
231	BOTAN_ARG_CHECK(version.is_pre_tls_13(), "Instantiated a TLS 1.2 session object with a TLS version newer than 1.2");	1,668✔
232	}	1,668✔
233
234	#if defined(BOTAN_HAS_TLS_13)
235
236	Session::Session(const secure_vector<uint8_t>& session_psk,	578✔
237	const std::optional<uint32_t>& max_early_data_bytes,
238	uint32_t ticket_age_add,
239	std::chrono::seconds lifetime_hint,
240	Protocol_Version version,
241	uint16_t ciphersuite,
242	Connection_Side side,
243	const std::vector<X509_Certificate>& peer_certs,
244	std::shared_ptr<const Public_Key> peer_raw_public_key,
245	const Server_Information& server_info,
246	std::chrono::system_clock::time_point current_timestamp) :	578✔
247	Session_Base(current_timestamp,
248	version,
249	ciphersuite,
250	side,
251
252	// TODO: SRTP might become necessary when DTLS 1.3 is being implemented
253	0,
254
255	// RFC 8446 Appendix D
256	// Because TLS 1.3 always hashes in the transcript up to the server
257	// Finished, implementations which support both TLS 1.3 and earlier
258	// versions SHOULD indicate the use of the Extended Master Secret
259	// extension in their APIs whenever TLS 1.3 is used.
260	true,
261
262	// TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
263	false,
264	peer_certs,
265	std::move(peer_raw_public_key),
266	server_info),
267	m_master_secret(session_psk),	578✔
268	m_early_data_allowed(max_early_data_bytes.has_value()),	578✔
269	m_max_early_data_bytes(max_early_data_bytes.value_or(0)),	578✔
270	m_ticket_age_add(ticket_age_add),	578✔
271	m_lifetime_hint(lifetime_hint) {	1,156✔
272	BOTAN_ARG_CHECK(!version.is_pre_tls_13(), "Instantiated a TLS 1.3 session object with a TLS version older than 1.3");	578✔
273	}	578✔
274
275	Session::Session(secure_vector<uint8_t>&& session_psk,	284✔
276	const std::optional<uint32_t>& max_early_data_bytes,
277	std::chrono::seconds lifetime_hint,
278	const std::vector<X509_Certificate>& peer_certs,
279	std::shared_ptr<const Public_Key> peer_raw_public_key,
280	const Client_Hello_13& client_hello,
281	const Server_Hello_13& server_hello,
282	Callbacks& callbacks,
283	RandomNumberGenerator& rng) :	284✔
284	Session_Base(callbacks.tls_current_timestamp(),	284✔
285	server_hello.selected_version(),
286	server_hello.ciphersuite(),	284✔
287	Connection_Side::Server,
288	0,
289	true,
290	false, // see constructor above for rationales
291	peer_certs,
292	std::move(peer_raw_public_key),
293	Server_Information(client_hello.sni_hostname())),	568✔
294	m_master_secret(std::move(session_psk)),	284✔
295	m_early_data_allowed(max_early_data_bytes.has_value()),	284✔
296	m_max_early_data_bytes(max_early_data_bytes.value_or(0)),	284✔
297	m_ticket_age_add(load_be<uint32_t>(rng.random_vec(4).data(), 0)),	284✔
298	m_lifetime_hint(lifetime_hint) {	852✔
299	BOTAN_ARG_CHECK(!m_version.is_pre_tls_13(),	284✔
300	"Instantiated a TLS 1.3 session object with a TLS version older than 1.3");
301	}	284✔
302
303	#endif
304
305	Session::Session(std::string_view pem) : Session(PEM_Code::decode_check_label(pem, "TLS SESSION")) {}	3✔
306
307	Session::Session(std::span<const uint8_t> ber_data) /* NOLINT(-member-init) / {	452✔
308	uint8_t side_code = 0;	452✔
309
310	std::vector<uint8_t> raw_pubkey_or_empty;	452✔
311
312	ASN1_String server_hostname;	452✔
313	ASN1_String server_service;	453✔
314	size_t server_port = 0;	452✔
315
316	uint8_t major_version = 0;	452✔
317	uint8_t minor_version = 0;	452✔
318
319	size_t start_time = 0;	452✔
320	size_t srtp_profile = 0;	452✔
321	uint16_t ciphersuite_code = 0;	452✔
322	uint64_t lifetime_hint = 0;	452✔
323
324	BER_Decoder(ber_data.data(), ber_data.size())	904✔
325	.start_sequence()	452✔
326	.decode_and_check(TLS_SESSION_PARAM_STRUCT_VERSION, "Unknown version in serialized TLS session")	904✔
327	.decode_integer_type(start_time)	452✔
328	.decode_integer_type(major_version)	452✔
329	.decode_integer_type(minor_version)	452✔
330	.decode_integer_type(ciphersuite_code)	452✔
331	.decode_integer_type(side_code)	452✔
332	.decode(m_extended_master_secret)	452✔
333	.decode(m_encrypt_then_mac)	452✔
334	.decode(m_master_secret, ASN1_Type::OctetString)	452✔
335	.decode_list<X509_Certificate>(m_peer_certs)	452✔
336	.decode(raw_pubkey_or_empty, ASN1_Type::OctetString)	452✔
337	.decode(server_hostname)	452✔
338	.decode(server_service)	452✔
339	.decode(server_port)	452✔
340	.decode(srtp_profile)	452✔
341	.decode(m_early_data_allowed)	452✔
342	.decode_integer_type(m_max_early_data_bytes)	452✔
343	.decode_integer_type(m_ticket_age_add)	452✔
344	.decode_integer_type(lifetime_hint)	452✔
345	.end_cons()	452✔
346	.verify_end();	452✔
347
348	if(!Ciphersuite::by_id(ciphersuite_code)) {	452✔
349	throw Decoding_Error(	1✔
350	"Serialized TLS session contains unknown cipher suite "
351	"(" +	2✔
352	std::to_string(ciphersuite_code) + ")");	4✔
353	}
354
355	m_ciphersuite = ciphersuite_code;	451✔
356	m_version = Protocol_Version(major_version, minor_version);	451✔
357	m_start_time = std::chrono::system_clock::from_time_t(start_time);	451✔
358	m_connection_side = static_cast<Connection_Side>(side_code);	451✔
359	m_srtp_profile = static_cast<uint16_t>(srtp_profile);	451✔
360
361	m_server_info =	451✔
362	Server_Information(server_hostname.value(), server_service.value(), static_cast<uint16_t>(server_port));	902✔
363
364	if(!raw_pubkey_or_empty.empty()) {	451✔
365	m_peer_raw_public_key = X509::load_key(raw_pubkey_or_empty);	1✔
366	}
367
368	m_lifetime_hint = std::chrono::seconds(lifetime_hint);	451✔
369	}	906✔
370
371	secure_vector<uint8_t> Session::DER_encode() const {	1,156✔
372	const auto raw_pubkey_or_empty =	1,156✔
373	m_peer_raw_public_key ? m_peer_raw_public_key->subject_public_key() : std::vector<uint8_t>{};	1,156✔
374
375	return DER_Encoder()	1,156✔
376	.start_sequence()	1,156✔
377	.encode(TLS_SESSION_PARAM_STRUCT_VERSION)	1,156✔
378	.encode(static_cast<size_t>(std::chrono::system_clock::to_time_t(m_start_time)))	1,156✔
379	.encode(static_cast<size_t>(m_version.major_version()))	1,156✔
380	.encode(static_cast<size_t>(m_version.minor_version()))	1,156✔
381	.encode(static_cast<size_t>(m_ciphersuite))	1,156✔
382	.encode(static_cast<size_t>(m_connection_side))	1,156✔
383	.encode(m_extended_master_secret)	1,156✔
384	.encode(m_encrypt_then_mac)	1,156✔
385	.encode(m_master_secret, ASN1_Type::OctetString)	1,156✔
386	.start_sequence()	1,576✔
387	.encode_list(m_peer_certs)	1,156✔
388	.end_cons()	1,156✔
389	.encode(raw_pubkey_or_empty, ASN1_Type::OctetString)	1,156✔
390	.encode(ASN1_String(m_server_info.hostname(), ASN1_Type::Utf8String))	3,468✔
391	.encode(ASN1_String(m_server_info.service(), ASN1_Type::Utf8String))	3,468✔
392	.encode(static_cast<size_t>(m_server_info.port()))	1,156✔
393	.encode(static_cast<size_t>(m_srtp_profile))	1,156✔
394
395	// the fields below were introduced for TLS 1.3 session tickets
396	.encode(m_early_data_allowed)	1,156✔
397	.encode(static_cast<size_t>(m_max_early_data_bytes))	1,156✔
398	.encode(static_cast<size_t>(m_ticket_age_add))	1,156✔
399	.encode(static_cast<size_t>(m_lifetime_hint.count()))	1,156✔
400	.end_cons()	1,156✔
401	.get_contents();	2,312✔
402	}	1,156✔
403
404	std::string Session::PEM_encode() const {	2✔
405	return PEM_Code::encode(this->DER_encode(), "TLS SESSION");	6✔
406	}
407
408	secure_vector<uint8_t> Session::extract_master_secret() {	171✔
409	BOTAN_STATE_CHECK(!m_master_secret.empty());	171✔
410	return std::exchange(m_master_secret, {});	171✔
411	}
412
413	namespace {
414
415	// The output length of the HMAC must be a valid keylength for the AEAD
416	const char* const TLS_SESSION_CRYPT_HMAC = "HMAC(SHA-512-256)";
417	// SIV would be better, but we can't assume it is available
418	const char* const TLS_SESSION_CRYPT_AEAD = "AES-256/GCM";
419	const char* const TLS_SESSION_CRYPT_KEY_NAME = "BOTAN TLS SESSION KEY NAME";
420	const uint64_t TLS_SESSION_CRYPT_MAGIC = 0x068B5A9D396C0000;
421	const size_t TLS_SESSION_CRYPT_MAGIC_LEN = 8;
422	const size_t TLS_SESSION_CRYPT_KEY_NAME_LEN = 4;
423	const size_t TLS_SESSION_CRYPT_AEAD_NONCE_LEN = 12;
424	const size_t TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN = 16;
425	const size_t TLS_SESSION_CRYPT_AEAD_TAG_SIZE = 16;
426
427	const size_t TLS_SESSION_CRYPT_HDR_LEN = TLS_SESSION_CRYPT_MAGIC_LEN + TLS_SESSION_CRYPT_KEY_NAME_LEN +
428	TLS_SESSION_CRYPT_AEAD_NONCE_LEN + TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN;
429
430	const size_t TLS_SESSION_CRYPT_OVERHEAD = TLS_SESSION_CRYPT_HDR_LEN + TLS_SESSION_CRYPT_AEAD_TAG_SIZE;
431
432	} // namespace
433
434	std::vector<uint8_t> Session::encrypt(const SymmetricKey& key, RandomNumberGenerator& rng) const {	1,148✔
435	auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);	1,148✔
436	hmac->set_key(key);	1,148✔
437
438	// First derive the "key name"
439	std::vector<uint8_t> key_name(hmac->output_length());	1,148✔
440	hmac->update(TLS_SESSION_CRYPT_KEY_NAME);	1,148✔
441	hmac->final(key_name.data());	1,148✔
442	key_name.resize(TLS_SESSION_CRYPT_KEY_NAME_LEN);	1,148✔
443
444	std::vector<uint8_t> aead_nonce;	1,148✔
445	std::vector<uint8_t> key_seed;	1,148✔
446
447	rng.random_vec(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);	1,148✔
448	rng.random_vec(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);	1,148✔
449
450	hmac->update(key_seed);	1,148✔
451	const secure_vector<uint8_t> aead_key = hmac->final();	1,148✔
452
453	secure_vector<uint8_t> bits = this->DER_encode();	1,148✔
454
455	// create the header
456	std::vector<uint8_t> buf;	1,148✔
457	buf.reserve(TLS_SESSION_CRYPT_OVERHEAD + bits.size());	1,148✔
458	buf.resize(TLS_SESSION_CRYPT_MAGIC_LEN);	1,148✔
459	store_be(TLS_SESSION_CRYPT_MAGIC, &buf[0]); // NOLINT(*container-data-pointer)	1,148✔
460	buf += key_name;	1,148✔
461	buf += key_seed;	1,148✔
462	buf += aead_nonce;	1,148✔
463
464	auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Encryption);	1,148✔
465	BOTAN_ASSERT_NOMSG(aead->valid_nonce_length(TLS_SESSION_CRYPT_AEAD_NONCE_LEN));	1,148✔
466	BOTAN_ASSERT_NOMSG(aead->tag_size() == TLS_SESSION_CRYPT_AEAD_TAG_SIZE);	1,148✔
467	aead->set_key(aead_key);	1,148✔
468	aead->set_associated_data(buf);	1,148✔
469	aead->start(aead_nonce);	1,148✔
470	aead->finish(bits, 0);	1,148✔
471
472	// append the ciphertext
473	buf += bits;	1,148✔
474	return buf;	1,148✔
475	}	4,592✔
476
477	Session Session::decrypt(std::span<const uint8_t> in, const SymmetricKey& key) {	453✔
478	try {	453✔
479	const size_t min_session_size = 48 + 4; // serious under-estimate	453✔
480	if(in.size() < TLS_SESSION_CRYPT_OVERHEAD + min_session_size) {	453✔
481	throw Decoding_Error("Encrypted session too short to be valid");	3✔
482	}
483
484	BufferSlicer sub(in);	450✔
485	const auto* const magic = sub.take(TLS_SESSION_CRYPT_MAGIC_LEN).data();	450✔
486	const auto* const key_name = sub.take(TLS_SESSION_CRYPT_KEY_NAME_LEN).data();	450✔
487	const auto* const key_seed = sub.take(TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN).data();	450✔
488	const auto* const aead_nonce = sub.take(TLS_SESSION_CRYPT_AEAD_NONCE_LEN).data();	450✔
489	auto ctext = sub.copy_as_secure_vector(sub.remaining());	450✔
490
491	if(load_be<uint64_t>(magic, 0) != TLS_SESSION_CRYPT_MAGIC) {	450✔
492	throw Decoding_Error("Missing expected magic numbers");	×
493	}
494
495	auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);	454✔
496	hmac->set_key(key);	450✔
497
498	// First derive and check the "key name"
499	std::vector<uint8_t> cmp_key_name(hmac->output_length());	454✔
500	hmac->update(TLS_SESSION_CRYPT_KEY_NAME);	450✔
501	hmac->final(cmp_key_name.data());	450✔
502
503	if(CT::is_equal(cmp_key_name.data(), key_name, TLS_SESSION_CRYPT_KEY_NAME_LEN).as_bool() == false) {	450✔
504	throw Decoding_Error("Wrong key name for encrypted session");	1✔
505	}
506
507	hmac->update(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);	449✔
508	const secure_vector<uint8_t> aead_key = hmac->final();	449✔
509
510	auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Decryption);	452✔
511	aead->set_key(aead_key);	449✔
512	aead->set_associated_data(in.data(), TLS_SESSION_CRYPT_HDR_LEN);	449✔
513	aead->start(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);	449✔
514	aead->finish(ctext, 0);	449✔
515	return Session(ctext);	449✔
516	} catch(std::exception& e) {	1,802✔
517	throw Decoding_Error("Failed to decrypt serialized TLS session: " + std::string(e.what()));	21✔
518	}	7✔
519	}
520
521	} // namespace Botan::TLS

randombit / botan / 21742894084

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