21712952425

Committed 05 Feb 2026 01:16PM UTC coverage: 90.076% (+0.005%) from 90.071%

Build # 21712952425

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Pull #5287

github

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web-flow

Commit Message

Merge 1b320c06e into 8c9623340

Pull Request Pull Request #5287: Split out BufferSlicer and BufferStuffer to their own headers

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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/tls_messages.h>
#include <botan/x509_key.h>
#include <botan/internal/buffer_slicer.h>
#include <botan/internal/ct_utils.h>
#include <botan/internal/loadstor.h>
#include <botan/internal/stl_util.h>

#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/tls_messages.h>
19	#include <botan/x509_key.h>
20	#include <botan/internal/buffer_slicer.h>
21	#include <botan/internal/ct_utils.h>
22	#include <botan/internal/loadstor.h>
23	#include <botan/internal/stl_util.h>
24
25	#include <utility>
26
27	namespace Botan::TLS {
28
29	void Session_Handle::validate_constraints() const {	3,552✔
30	std::visit(overloaded{	7,104✔
31	[](const Session_ID& id) {	696✔
32	// RFC 5246 7.4.1.2
33	// opaque SessionID<0..32>;
34	BOTAN_ARG_CHECK(!id.empty(), "Session ID must not be empty");	696✔
35	BOTAN_ARG_CHECK(id.size() <= 32, "Session ID cannot be longer than 32 bytes");	696✔
36	},	696✔
37	[](const Session_Ticket& ticket) {	2,167✔
38	BOTAN_ARG_CHECK(!ticket.empty(), "Ticket most not be empty");	2,167✔
39	BOTAN_ARG_CHECK(ticket.size() <= std::numeric_limits<uint16_t>::max(),	2,167✔
40	"Ticket cannot be longer than 64kB");
41	},	2,167✔
42	[](const Opaque_Session_Handle& handle) {	689✔
43	// RFC 8446 4.6.1
44	// opaque ticket<1..2^16-1>;
45	BOTAN_ARG_CHECK(!handle.empty(), "Opaque session handle must not be empty");	689✔
46	BOTAN_ARG_CHECK(handle.size() <= std::numeric_limits<uint16_t>::max(),	689✔
47	"Opaque session handle cannot be longer than 64kB");
48	},	689✔
49	},
50	m_handle);	3,552✔
51	}	3,552✔
52
53	Opaque_Session_Handle Session_Handle::opaque_handle() const {	367✔
54	// both a Session_ID and a Session_Ticket could be an Opaque_Session_Handle
55	return Opaque_Session_Handle(std::visit([](const auto& handle) { return handle.get(); }, m_handle));	734✔
56	}
57
58	std::optional<Session_ID> Session_Handle::id() const {	2,468✔
59	if(is_id()) {	2,468✔
60	return std::get<Session_ID>(m_handle);	634✔
61	}
62
63	// Opaque handles can mimic as a Session_ID if they are short enough
64	if(is_opaque_handle()) {	1,834✔
65	const auto& handle = std::get<Opaque_Session_Handle>(m_handle);	680✔
66	if(handle.size() <= 32) {	680✔
67	return Session_ID(handle.get());	27✔
68	}
69	}
70
71	return std::nullopt;	1,807✔
72	}
73
74	std::optional<Session_Ticket> Session_Handle::ticket() const {	1,771✔
75	if(is_ticket()) {	1,771✔
76	return std::get<Session_Ticket>(m_handle);	1,220✔
77	}
78
79	// Opaque handles can mimic 'normal' Session_Tickets at any time
80	if(is_opaque_handle()) {	551✔
81	return Session_Ticket(std::get<Opaque_Session_Handle>(m_handle).get());	210✔
82	}
83
84	return std::nullopt;	341✔
85	}
86
87	Ciphersuite Session_Base::ciphersuite() const {	4,908✔
88	auto suite = Ciphersuite::by_id(m_ciphersuite);	4,908✔
89	if(!suite.has_value()) {	4,908✔
90	throw Decoding_Error("Failed to find cipher suite for ID " + std::to_string(m_ciphersuite));	×
91	}
92	return suite.value();	4,908✔
93	}
94
95	Session_Summary::Session_Summary(const Session_Base& base,	1,785✔
96	bool was_resumption,
97	std::optional<std::string> psk_identity) :	1,785✔
98	Session_Base(base), m_external_psk_identity(std::move(psk_identity)), m_was_resumption(was_resumption) {	1,904✔
99	BOTAN_ARG_CHECK(version().is_pre_tls_13(), "Instantiated a TLS 1.2 session summary with an newer TLS version");	1,785✔
100
101	const auto cs = ciphersuite();	1,785✔
102	m_kex_algo = cs.kex_algo();	1,785✔
103	}	1,785✔
104
105	#if defined(BOTAN_HAS_TLS_13)
106
107	namespace {
108
109	std::string tls13_kex_to_string(bool psk, std::optional<Named_Group> group) {	610✔
110	if(psk && group) {	610✔
111	if(group->is_dh_named_group()) {	159✔
112	return kex_method_to_string(Kex_Algo::DHE_PSK);	×
113	} else if(group->is_ecdh_named_curve() \|\| group->is_x25519() \|\| group->is_x448()) {	159✔
114	return kex_method_to_string(Kex_Algo::ECDHE_PSK);	157✔
115	} else if(group->is_pure_ml_kem() \|\| group->is_pure_frodokem()) {	2✔
116	return kex_method_to_string(Kex_Algo::KEM_PSK);	×
117	} else if(group->is_pqc_hybrid()) {	2✔
118	return kex_method_to_string(Kex_Algo::HYBRID_PSK);	2✔
119	} else if(auto s = group->to_string()) {	×
120	return *s;	×
121	}	×
122	} else if(psk) {	451✔
123	return kex_method_to_string(Kex_Algo::PSK);	×
124	} else {
125	BOTAN_ASSERT_NOMSG(group.has_value());	451✔
126	if(group->is_dh_named_group()) {	451✔
127	return kex_method_to_string(Kex_Algo::DH);	×
128	} else if(group->is_ecdh_named_curve() \|\| group->is_x25519() \|\| group->is_x448()) {	451✔
129	return kex_method_to_string(Kex_Algo::ECDH);	419✔
130	} else if(group->is_pure_ml_kem() \|\| group->is_pure_frodokem()) {	32✔
131	return kex_method_to_string(Kex_Algo::KEM);	2✔
132	} else if(group->is_pqc_hybrid()) {	30✔
133	return kex_method_to_string(Kex_Algo::HYBRID);	30✔
134	} else if(auto s = group->to_string()) {	×
135	return *s;	×
136	}	×
137	}
138
139	return kex_method_to_string(Kex_Algo::UNDEFINED);	×
140	}
141
142	} // namespace
143
144	Session_Summary::Session_Summary(const Server_Hello_13& server_hello,	610✔
145	Connection_Side side,
146	std::vector<X509_Certificate> peer_certs,
147	std::shared_ptr<const Public_Key> peer_raw_public_key,
148	std::optional<std::string> psk_identity,
149	bool session_was_resumed,
150	Server_Information server_info,
151	std::chrono::system_clock::time_point current_timestamp) :	610✔
152	Session_Base(current_timestamp,
153	server_hello.selected_version(),
154	server_hello.ciphersuite(),	610✔
155	side,
156
157	// TODO: SRTP might become necessary when DTLS 1.3 is being implemented
158	0,
159
160	// RFC 8446 Appendix D
161	// Because TLS 1.3 always hashes in the transcript up to the server
162	// Finished, implementations which support both TLS 1.3 and earlier
163	// versions SHOULD indicate the use of the Extended Master Secret
164	// extension in their APIs whenever TLS 1.3 is used.
165	true,
166
167	// TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
168	false,
169	std::move(peer_certs),
170	std::move(peer_raw_public_key),
171	std::move(server_info)),
172	m_external_psk_identity(std::move(psk_identity)),	610✔
173	m_was_resumption(session_was_resumed) {	1,834✔
174	BOTAN_ARG_CHECK(version().is_tls_13_or_later(), "Instantiated a TLS 1.3 session summary with an older TLS version");	610✔
175	set_session_id(server_hello.session_id());	1,220✔
176
177	// In TLS 1.3 the key exchange algorithm is not negotiated in the ciphersuite
178	// anymore. This provides a compatible identifier for applications to use.
179
180	std::optional<Named_Group> group = [&]() -> std::optional<Named_Group> {	1,830✔
181	if(psk_used() \|\| was_resumption()) {	610✔
182	if(auto* const keyshare = server_hello.extensions().get<Key_Share>()) {	159✔
183	return keyshare->selected_group();	159✔
184	} else {
185	return {};	×
186	}
187	} else {
188	auto* const keyshare = server_hello.extensions().get<Key_Share>();	451✔
189	BOTAN_ASSERT_NONNULL(keyshare);	451✔
190	return keyshare->selected_group();	451✔
191	}
192	}();	610✔
193
194	if(group.has_value()) {	610✔
195	m_kex_parameters = group->to_string();	1,220✔
196	}
197
198	m_kex_algo = tls13_kex_to_string(psk_used() \|\| was_resumption(), group);	610✔
199	}	610✔
200
201	#endif
202
203	Session::Session(const secure_vector<uint8_t>& master_secret,	1,667✔
204	Protocol_Version version,
205	uint16_t ciphersuite,
206	Connection_Side side,
207	bool extended_master_secret,
208	bool encrypt_then_mac,
209	const std::vector<X509_Certificate>& certs,
210	const Server_Information& server_info,
211	uint16_t srtp_profile,
212	std::chrono::system_clock::time_point current_timestamp,
213	std::chrono::seconds lifetime_hint) :	1,667✔
214	Session_Base(current_timestamp,
215	version,
216	ciphersuite,
217	side,
218	srtp_profile,
219	extended_master_secret,
220	encrypt_then_mac,
221	certs,
222	nullptr, // RFC 7250 (raw public keys) is NYI for TLS 1.2
223	server_info),
224	m_master_secret(master_secret),	1,667✔
225	m_early_data_allowed(false),	1,667✔
226	m_max_early_data_bytes(0),	1,667✔
227	m_ticket_age_add(0),	1,667✔
228	m_lifetime_hint(lifetime_hint) {	3,334✔
229	BOTAN_ARG_CHECK(version.is_pre_tls_13(), "Instantiated a TLS 1.2 session object with a TLS version newer than 1.2");	1,667✔
230	}	1,667✔
231
232	#if defined(BOTAN_HAS_TLS_13)
233
234	Session::Session(const secure_vector<uint8_t>& session_psk,	578✔
235	const std::optional<uint32_t>& max_early_data_bytes,
236	uint32_t ticket_age_add,
237	std::chrono::seconds lifetime_hint,
238	Protocol_Version version,
239	uint16_t ciphersuite,
240	Connection_Side side,
241	const std::vector<X509_Certificate>& peer_certs,
242	std::shared_ptr<const Public_Key> peer_raw_public_key,
243	const Server_Information& server_info,
244	std::chrono::system_clock::time_point current_timestamp) :	578✔
245	Session_Base(current_timestamp,
246	version,
247	ciphersuite,
248	side,
249
250	// TODO: SRTP might become necessary when DTLS 1.3 is being implemented
251	0,
252
253	// RFC 8446 Appendix D
254	// Because TLS 1.3 always hashes in the transcript up to the server
255	// Finished, implementations which support both TLS 1.3 and earlier
256	// versions SHOULD indicate the use of the Extended Master Secret
257	// extension in their APIs whenever TLS 1.3 is used.
258	true,
259
260	// TLS 1.3 uses AEADs, so technically encrypt-then-MAC is not applicable.
261	false,
262	peer_certs,
263	std::move(peer_raw_public_key),
264	server_info),
265	m_master_secret(session_psk),	578✔
266	m_early_data_allowed(max_early_data_bytes.has_value()),	578✔
267	m_max_early_data_bytes(max_early_data_bytes.value_or(0)),	578✔
268	m_ticket_age_add(ticket_age_add),	578✔
269	m_lifetime_hint(lifetime_hint) {	1,156✔
270	BOTAN_ARG_CHECK(!version.is_pre_tls_13(), "Instantiated a TLS 1.3 session object with a TLS version older than 1.3");	578✔
271	}	578✔
272
273	Session::Session(secure_vector<uint8_t>&& session_psk,	284✔
274	const std::optional<uint32_t>& max_early_data_bytes,
275	std::chrono::seconds lifetime_hint,
276	const std::vector<X509_Certificate>& peer_certs,
277	std::shared_ptr<const Public_Key> peer_raw_public_key,
278	const Client_Hello_13& client_hello,
279	const Server_Hello_13& server_hello,
280	Callbacks& callbacks,
281	RandomNumberGenerator& rng) :	284✔
282	Session_Base(callbacks.tls_current_timestamp(),	284✔
283	server_hello.selected_version(),
284	server_hello.ciphersuite(),	284✔
285	Connection_Side::Server,
286	0,
287	true,
288	false, // see constructor above for rationales
289	peer_certs,
290	std::move(peer_raw_public_key),
291	Server_Information(client_hello.sni_hostname())),	568✔
292	m_master_secret(std::move(session_psk)),	284✔
293	m_early_data_allowed(max_early_data_bytes.has_value()),	284✔
294	m_max_early_data_bytes(max_early_data_bytes.value_or(0)),	284✔
295	m_ticket_age_add(load_be<uint32_t>(rng.random_vec(4).data(), 0)),	284✔
296	m_lifetime_hint(lifetime_hint) {	852✔
297	BOTAN_ARG_CHECK(!m_version.is_pre_tls_13(),	284✔
298	"Instantiated a TLS 1.3 session object with a TLS version older than 1.3");
299	}	284✔
300
301	#endif
302
303	Session::Session(std::string_view pem) : Session(PEM_Code::decode_check_label(pem, "TLS SESSION")) {}	3✔
304
305	Session::Session(std::span<const uint8_t> ber_data) /* NOLINT(-member-init) / {	451✔
306	uint8_t side_code = 0;	451✔
307
308	std::vector<uint8_t> raw_pubkey_or_empty;	451✔
309
310	ASN1_String server_hostname;	451✔
311	ASN1_String server_service;	452✔
312	size_t server_port = 0;	451✔
313
314	uint8_t major_version = 0;	451✔
315	uint8_t minor_version = 0;	451✔
316
317	size_t start_time = 0;	451✔
318	size_t srtp_profile = 0;	451✔
319	uint16_t ciphersuite_code = 0;	451✔
320	uint64_t lifetime_hint = 0;	451✔
321
322	BER_Decoder(ber_data.data(), ber_data.size())	902✔
323	.start_sequence()	451✔
324	.decode_and_check(TLS_SESSION_PARAM_STRUCT_VERSION, "Unknown version in serialized TLS session")	902✔
325	.decode_integer_type(start_time)	451✔
326	.decode_integer_type(major_version)	451✔
327	.decode_integer_type(minor_version)	451✔
328	.decode_integer_type(ciphersuite_code)	451✔
329	.decode_integer_type(side_code)	451✔
330	.decode(m_extended_master_secret)	451✔
331	.decode(m_encrypt_then_mac)	451✔
332	.decode(m_master_secret, ASN1_Type::OctetString)	451✔
333	.decode_list<X509_Certificate>(m_peer_certs)	451✔
334	.decode(raw_pubkey_or_empty, ASN1_Type::OctetString)	451✔
335	.decode(server_hostname)	451✔
336	.decode(server_service)	451✔
337	.decode(server_port)	451✔
338	.decode(srtp_profile)	451✔
339	.decode(m_early_data_allowed)	451✔
340	.decode_integer_type(m_max_early_data_bytes)	451✔
341	.decode_integer_type(m_ticket_age_add)	451✔
342	.decode_integer_type(lifetime_hint)	451✔
343	.end_cons()	451✔
344	.verify_end();	451✔
345
346	if(!Ciphersuite::by_id(ciphersuite_code)) {	451✔
347	throw Decoding_Error(	1✔
348	"Serialized TLS session contains unknown cipher suite "
349	"(" +	2✔
350	std::to_string(ciphersuite_code) + ")");	4✔
351	}
352
353	m_ciphersuite = ciphersuite_code;	450✔
354	m_version = Protocol_Version(major_version, minor_version);	450✔
355	m_start_time = std::chrono::system_clock::from_time_t(start_time);	450✔
356	m_connection_side = static_cast<Connection_Side>(side_code);	450✔
357	m_srtp_profile = static_cast<uint16_t>(srtp_profile);	450✔
358
359	m_server_info =	450✔
360	Server_Information(server_hostname.value(), server_service.value(), static_cast<uint16_t>(server_port));	900✔
361
362	if(!raw_pubkey_or_empty.empty()) {	450✔
363	m_peer_raw_public_key = X509::load_key(raw_pubkey_or_empty);	1✔
364	}
365
366	m_lifetime_hint = std::chrono::seconds(lifetime_hint);	450✔
367	}	904✔
368
369	secure_vector<uint8_t> Session::DER_encode() const {	1,157✔
370	const auto raw_pubkey_or_empty =	1,157✔
371	m_peer_raw_public_key ? m_peer_raw_public_key->subject_public_key() : std::vector<uint8_t>{};	1,157✔
372
373	return DER_Encoder()	1,157✔
374	.start_sequence()	1,157✔
375	.encode(TLS_SESSION_PARAM_STRUCT_VERSION)	1,157✔
376	.encode(static_cast<size_t>(std::chrono::system_clock::to_time_t(m_start_time)))	1,157✔
377	.encode(static_cast<size_t>(m_version.major_version()))	1,157✔
378	.encode(static_cast<size_t>(m_version.minor_version()))	1,157✔
379	.encode(static_cast<size_t>(m_ciphersuite))	1,157✔
380	.encode(static_cast<size_t>(m_connection_side))	1,157✔
381	.encode(m_extended_master_secret)	1,157✔
382	.encode(m_encrypt_then_mac)	1,157✔
383	.encode(m_master_secret, ASN1_Type::OctetString)	1,157✔
384	.start_sequence()	1,579✔
385	.encode_list(m_peer_certs)	1,157✔
386	.end_cons()	1,157✔
387	.encode(raw_pubkey_or_empty, ASN1_Type::OctetString)	1,157✔
388	.encode(ASN1_String(m_server_info.hostname(), ASN1_Type::Utf8String))	3,471✔
389	.encode(ASN1_String(m_server_info.service(), ASN1_Type::Utf8String))	3,471✔
390	.encode(static_cast<size_t>(m_server_info.port()))	1,157✔
391	.encode(static_cast<size_t>(m_srtp_profile))	1,157✔
392
393	// the fields below were introduced for TLS 1.3 session tickets
394	.encode(m_early_data_allowed)	1,157✔
395	.encode(static_cast<size_t>(m_max_early_data_bytes))	1,157✔
396	.encode(static_cast<size_t>(m_ticket_age_add))	1,157✔
397	.encode(static_cast<size_t>(m_lifetime_hint.count()))	1,157✔
398	.end_cons()	1,157✔
399	.get_contents();	2,314✔
400	}	1,157✔
401
402	std::string Session::PEM_encode() const {	2✔
403	return PEM_Code::encode(this->DER_encode(), "TLS SESSION");	6✔
404	}
405
406	secure_vector<uint8_t> Session::extract_master_secret() {	171✔
407	BOTAN_STATE_CHECK(!m_master_secret.empty());	171✔
408	return std::exchange(m_master_secret, {});	171✔
409	}
410
411	namespace {
412
413	// The output length of the HMAC must be a valid keylength for the AEAD
414	const char* const TLS_SESSION_CRYPT_HMAC = "HMAC(SHA-512-256)";
415	// SIV would be better, but we can't assume it is available
416	const char* const TLS_SESSION_CRYPT_AEAD = "AES-256/GCM";
417	const char* const TLS_SESSION_CRYPT_KEY_NAME = "BOTAN TLS SESSION KEY NAME";
418	const uint64_t TLS_SESSION_CRYPT_MAGIC = 0x068B5A9D396C0000;
419	const size_t TLS_SESSION_CRYPT_MAGIC_LEN = 8;
420	const size_t TLS_SESSION_CRYPT_KEY_NAME_LEN = 4;
421	const size_t TLS_SESSION_CRYPT_AEAD_NONCE_LEN = 12;
422	const size_t TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN = 16;
423	const size_t TLS_SESSION_CRYPT_AEAD_TAG_SIZE = 16;
424
425	const size_t TLS_SESSION_CRYPT_HDR_LEN = TLS_SESSION_CRYPT_MAGIC_LEN + TLS_SESSION_CRYPT_KEY_NAME_LEN +
426	TLS_SESSION_CRYPT_AEAD_NONCE_LEN + TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN;
427
428	const size_t TLS_SESSION_CRYPT_OVERHEAD = TLS_SESSION_CRYPT_HDR_LEN + TLS_SESSION_CRYPT_AEAD_TAG_SIZE;
429
430	} // namespace
431
432	std::vector<uint8_t> Session::encrypt(const SymmetricKey& key, RandomNumberGenerator& rng) const {	1,149✔
433	auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);	1,149✔
434	hmac->set_key(key);	1,149✔
435
436	// First derive the "key name"
437	std::vector<uint8_t> key_name(hmac->output_length());	1,149✔
438	hmac->update(TLS_SESSION_CRYPT_KEY_NAME);	1,149✔
439	hmac->final(key_name.data());	1,149✔
440	key_name.resize(TLS_SESSION_CRYPT_KEY_NAME_LEN);	1,149✔
441
442	std::vector<uint8_t> aead_nonce;	1,149✔
443	std::vector<uint8_t> key_seed;	1,149✔
444
445	rng.random_vec(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);	1,149✔
446	rng.random_vec(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);	1,149✔
447
448	hmac->update(key_seed);	1,149✔
449	const secure_vector<uint8_t> aead_key = hmac->final();	1,149✔
450
451	secure_vector<uint8_t> bits = this->DER_encode();	1,149✔
452
453	// create the header
454	std::vector<uint8_t> buf;	1,149✔
455	buf.reserve(TLS_SESSION_CRYPT_OVERHEAD + bits.size());	1,149✔
456	buf.resize(TLS_SESSION_CRYPT_MAGIC_LEN);	1,149✔
457	store_be(TLS_SESSION_CRYPT_MAGIC, &buf[0]); // NOLINT(*container-data-pointer)	1,149✔
458	buf += key_name;	1,149✔
459	buf += key_seed;	1,149✔
460	buf += aead_nonce;	1,149✔
461
462	auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Encryption);	1,149✔
463	BOTAN_ASSERT_NOMSG(aead->valid_nonce_length(TLS_SESSION_CRYPT_AEAD_NONCE_LEN));	1,149✔
464	BOTAN_ASSERT_NOMSG(aead->tag_size() == TLS_SESSION_CRYPT_AEAD_TAG_SIZE);	1,149✔
465	aead->set_key(aead_key);	1,149✔
466	aead->set_associated_data(buf);	1,149✔
467	aead->start(aead_nonce);	1,149✔
468	aead->finish(bits, 0);	1,149✔
469
470	// append the ciphertext
471	buf += bits;	1,149✔
472	return buf;	1,149✔
473	}	4,596✔
474
475	Session Session::decrypt(std::span<const uint8_t> in, const SymmetricKey& key) {	452✔
476	try {	452✔
477	const size_t min_session_size = 48 + 4; // serious under-estimate	452✔
478	if(in.size() < TLS_SESSION_CRYPT_OVERHEAD + min_session_size) {	452✔
479	throw Decoding_Error("Encrypted session too short to be valid");	3✔
480	}
481
482	BufferSlicer sub(in);	449✔
483	const auto* const magic = sub.take(TLS_SESSION_CRYPT_MAGIC_LEN).data();	449✔
484	const auto* const key_name = sub.take(TLS_SESSION_CRYPT_KEY_NAME_LEN).data();	449✔
485	const auto* const key_seed = sub.take(TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN).data();	449✔
486	const auto* const aead_nonce = sub.take(TLS_SESSION_CRYPT_AEAD_NONCE_LEN).data();	449✔
487	auto ctext = sub.copy_as_secure_vector(sub.remaining());	449✔
488
489	if(load_be<uint64_t>(magic, 0) != TLS_SESSION_CRYPT_MAGIC) {	449✔
490	throw Decoding_Error("Missing expected magic numbers");	×
491	}
492
493	auto hmac = MessageAuthenticationCode::create_or_throw(TLS_SESSION_CRYPT_HMAC);	453✔
494	hmac->set_key(key);	449✔
495
496	// First derive and check the "key name"
497	std::vector<uint8_t> cmp_key_name(hmac->output_length());	453✔
498	hmac->update(TLS_SESSION_CRYPT_KEY_NAME);	449✔
499	hmac->final(cmp_key_name.data());	449✔
500
501	if(CT::is_equal(cmp_key_name.data(), key_name, TLS_SESSION_CRYPT_KEY_NAME_LEN).as_bool() == false) {	449✔
502	throw Decoding_Error("Wrong key name for encrypted session");	1✔
503	}
504
505	hmac->update(key_seed, TLS_SESSION_CRYPT_AEAD_KEY_SEED_LEN);	448✔
506	const secure_vector<uint8_t> aead_key = hmac->final();	448✔
507
508	auto aead = AEAD_Mode::create_or_throw(TLS_SESSION_CRYPT_AEAD, Cipher_Dir::Decryption);	451✔
509	aead->set_key(aead_key);	448✔
510	aead->set_associated_data(in.data(), TLS_SESSION_CRYPT_HDR_LEN);	448✔
511	aead->start(aead_nonce, TLS_SESSION_CRYPT_AEAD_NONCE_LEN);	448✔
512	aead->finish(ctext, 0);	448✔
513	return Session(ctext);	448✔
514	} catch(std::exception& e) {	1,798✔
515	throw Decoding_Error("Failed to decrypt serialized TLS session: " + std::string(e.what()));	21✔
516	}	7✔
517	}
518
519	} // namespace Botan::TLS

randombit / botan / 21712952425

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