Botan 3.5.0
Crypto and TLS for C&
Botan::TLS::Hello_Retry_Request Class Referencefinal

#include <tls_messages.h>

Inheritance diagram for Botan::TLS::Hello_Retry_Request:
Botan::TLS::Server_Hello_13 Botan::TLS::Server_Hello Botan::TLS::Handshake_Message

Public Member Functions

uint16_t ciphersuite () const
 
const Extensionsextensions () const
 
std::optional< Protocol_Versionrandom_signals_downgrade () const
 
Protocol_Version selected_version () const final
 
std::vector< uint8_t > serialize () const override
 
const Session_IDsession_id () const
 
Handshake_Type type () const override
 
std::string type_string () const
 
Handshake_Type wire_type () const override
 

Static Public Member Functions

static std::variant< Hello_Retry_Request, Server_Hello_13create (const Client_Hello_13 &ch, bool hello_retry_request_allowed, Session_Manager &session_mgr, Credentials_Manager &credentials_mgr, RandomNumberGenerator &rng, const Policy &policy, Callbacks &cb)
 
static std::variant< Hello_Retry_Request, Server_Hello_13, Server_Hello_12parse (const std::vector< uint8_t > &buf)
 

Protected Member Functions

void basic_validation () const
 
uint8_t compression_method () const
 
std::set< Extension_Codeextension_types () const
 
 Hello_Retry_Request (const Client_Hello_13 &ch, Named_Group selected_group, const Policy &policy, Callbacks &cb)
 
 Hello_Retry_Request (std::unique_ptr< Server_Hello_Internal > data)
 
Protocol_Version legacy_version () const
 
const std::vector< uint8_t > & random () const
 

Protected Attributes

std::unique_ptr< Server_Hello_Internal > m_data
 

Static Protected Attributes

static const struct Botan::TLS::Server_Hello_13::Hello_Retry_Request_Tag as_hello_retry_request
 
static const struct Botan::TLS::Server_Hello_13::Hello_Retry_Request_Creation_Tag as_new_hello_retry_request
 
static const struct Botan::TLS::Server_Hello_13::Server_Hello_Tag as_server_hello
 

Friends

class Server_Hello_13
 

Detailed Description

Definition at line 453 of file tls_messages.h.

Constructor & Destructor Documentation

◆ Hello_Retry_Request() [1/2]

Botan::TLS::Hello_Retry_Request::Hello_Retry_Request ( std::unique_ptr< Server_Hello_Internal > data)
explicitprotected

Definition at line 785 of file msg_server_hello.cpp.

785 :
static const struct Botan::TLS::Server_Hello_13::Hello_Retry_Request_Tag as_hello_retry_request

◆ Hello_Retry_Request() [2/2]

Botan::TLS::Hello_Retry_Request::Hello_Retry_Request ( const Client_Hello_13 & ch,
Named_Group selected_group,
const Policy & policy,
Callbacks & cb )
protected

Definition at line 788 of file msg_server_hello.cpp.

791 :
792 Server_Hello_13(std::make_unique<Server_Hello_Internal>(Protocol_Version::TLS_V12 /* legacy_version */,
793 ch.session_id(),
794 HELLO_RETRY_REQUEST_MARKER,
795 choose_ciphersuite(ch, policy),
796 uint8_t(0) /* compression method */,
797 true /* is Hello Retry Request */
798 ),
800 // RFC 8446 4.1.4
801 // As with the ServerHello, a HelloRetryRequest MUST NOT contain any
802 // extensions that were not first offered by the client in its
803 // ClientHello, with the exception of optionally the "cookie" [...]
804 // extension.
805 BOTAN_STATE_CHECK(ch.extensions().has<Supported_Groups>());
806 BOTAN_STATE_CHECK(ch.extensions().has<Key_Share>());
807
808 BOTAN_STATE_CHECK(!value_exists(ch.extensions().get<Key_Share>()->offered_groups(), selected_group));
809
810 // RFC 8446 4.1.4
811 // The server's extensions MUST contain "supported_versions".
812 //
813 // RFC 8446 4.2.1
814 // A server which negotiates TLS 1.3 MUST respond by sending a
815 // "supported_versions" extension containing the selected version
816 // value (0x0304). It MUST set the ServerHello.legacy_version field to
817 // 0x0303 (TLS 1.2).
818 //
819 // Note that the legacy version (TLS 1.2) is set in this constructor's
820 // initializer list, accordingly.
821 m_data->extensions().add(new Supported_Versions(Protocol_Version::TLS_V13));
822
823 m_data->extensions().add(new Key_Share(selected_group));
824
825 cb.tls_modify_extensions(m_data->extensions(), Connection_Side::Server, type());
826}
#define BOTAN_STATE_CHECK(expr)
Definition assert.h:41
Handshake_Type type() const override
static const struct Botan::TLS::Server_Hello_13::Hello_Retry_Request_Creation_Tag as_new_hello_retry_request
std::unique_ptr< Server_Hello_Internal > m_data
bool value_exists(const std::vector< T > &vec, const OT &val)
Definition stl_util.h:60

References BOTAN_STATE_CHECK, Botan::TLS::Client_Hello::extensions(), Botan::TLS::Extensions::get(), Botan::TLS::Extensions::has(), Botan::TLS::Server_Hello::m_data, Botan::TLS::Key_Share::offered_groups(), Botan::TLS::Server, Botan::TLS::Callbacks::tls_modify_extensions(), type(), and Botan::value_exists().

Member Function Documentation

◆ basic_validation()

void Botan::TLS::Server_Hello_13::basic_validation ( ) const
protectedinherited

Validation that applies to both Server Hello and Hello Retry Request

Definition at line 540 of file msg_server_hello.cpp.

540 {
541 BOTAN_ASSERT_NOMSG(m_data->version() == Protocol_Version::TLS_V13);
542
543 // Note: checks that cannot be performed without contextual information
544 // are done in the specific TLS client implementation.
545 // Note: The Supported_Version extension makes sure internally that
546 // exactly one entry is provided.
547
548 // Note: Hello Retry Request basic validation is equivalent with the
549 // basic validations required for Server Hello
550 //
551 // RFC 8446 4.1.4
552 // Upon receipt of a HelloRetryRequest, the client MUST check the
553 // legacy_version, [...], and legacy_compression_method as specified in
554 // Section 4.1.3 and then process the extensions, starting with determining
555 // the version using "supported_versions".
556
557 // RFC 8446 4.1.3
558 // In TLS 1.3, [...] the legacy_version field MUST be set to 0x0303
559 if(legacy_version() != Protocol_Version::TLS_V12) {
560 throw TLS_Exception(Alert::ProtocolVersion,
561 "legacy_version '" + legacy_version().to_string() + "' is not allowed");
562 }
563
564 // RFC 8446 4.1.3
565 // legacy_compression_method: A single byte which MUST have the value 0.
566 if(compression_method() != 0x00) {
567 throw TLS_Exception(Alert::DecodeError, "compression is not supported in TLS 1.3");
568 }
569
570 // RFC 8446 4.1.3
571 // All TLS 1.3 ServerHello messages MUST contain the "supported_versions" extension.
572 if(!extensions().has<Supported_Versions>()) {
573 throw TLS_Exception(Alert::MissingExtension, "server hello did not contain 'supported version' extension");
574 }
575
576 // RFC 8446 4.2.1
577 // A server which negotiates TLS 1.3 MUST respond by sending
578 // a "supported_versions" extension containing the selected version
579 // value (0x0304).
580 if(selected_version() != Protocol_Version::TLS_V13) {
581 throw TLS_Exception(Alert::IllegalParameter, "TLS 1.3 Server Hello selected a different version");
582 }
583}
#define BOTAN_ASSERT_NOMSG(expr)
Definition assert.h:59
Protocol_Version selected_version() const final
const Extensions & extensions() const
Protocol_Version legacy_version() const
std::string to_string(ErrorType type)
Convert an ErrorType to string.
Definition exceptn.cpp:13

References BOTAN_ASSERT_NOMSG, Botan::TLS::Server_Hello::compression_method(), Botan::TLS::Server_Hello::extensions(), Botan::TLS::Server_Hello::legacy_version(), Botan::TLS::Server_Hello::m_data, Botan::TLS::Server_Hello_13::selected_version(), and Botan::to_string().

Referenced by Botan::TLS::Server_Hello_13::Server_Hello_13(), and Botan::TLS::Server_Hello_13::Server_Hello_13().

◆ ciphersuite()

uint16_t Botan::TLS::Server_Hello::ciphersuite ( ) const
inherited

Definition at line 218 of file msg_server_hello.cpp.

218 {
219 return m_data->ciphersuite();
220}

References Botan::TLS::Server_Hello::m_data.

Referenced by Botan::TLS::Client_Hello_13::retry().

◆ compression_method()

uint8_t Botan::TLS::Server_Hello::compression_method ( ) const
protectedinherited

Definition at line 210 of file msg_server_hello.cpp.

210 {
211 return m_data->comp_method();
212}

References Botan::TLS::Server_Hello::m_data.

Referenced by Botan::TLS::Server_Hello_13::basic_validation().

◆ create()

std::variant< Hello_Retry_Request, Server_Hello_13 > Botan::TLS::Server_Hello_13::create ( const Client_Hello_13 & ch,
bool hello_retry_request_allowed,
Session_Manager & session_mgr,
Credentials_Manager & credentials_mgr,
RandomNumberGenerator & rng,
const Policy & policy,
Callbacks & cb )
staticinherited

Definition at line 459 of file msg_server_hello.cpp.

465 {
466 const auto& exts = ch.extensions();
467
468 // RFC 8446 4.2.9
469 // [With PSK with (EC)DHE key establishment], the client and server MUST
470 // supply "key_share" values [...].
471 //
472 // Note: We currently do not support PSK without (EC)DHE, hence, we can
473 // assume that those extensions are available.
474 BOTAN_ASSERT_NOMSG(exts.has<Supported_Groups>() && exts.has<Key_Share>());
475 const auto& supported_by_client = exts.get<Supported_Groups>()->groups();
476 const auto& offered_by_client = exts.get<Key_Share>()->offered_groups();
477 const auto selected_group = policy.choose_key_exchange_group(supported_by_client, offered_by_client);
478
479 // RFC 8446 4.1.1
480 // If there is no overlap between the received "supported_groups" and the
481 // groups supported by the server, then the server MUST abort the
482 // handshake with a "handshake_failure" or an "insufficient_security" alert.
483 if(selected_group == Named_Group::NONE) {
484 throw TLS_Exception(Alert::HandshakeFailure, "Client did not offer any acceptable group");
485 }
486
487 // RFC 8446 4.2.8:
488 // Servers MUST NOT send a KeyShareEntry for any group not indicated in the
489 // client's "supported_groups" extension [...]
490 if(!value_exists(supported_by_client, selected_group)) {
491 throw TLS_Exception(Alert::InternalError, "Application selected a group that is not supported by the client");
492 }
493
494 // RFC 8446 4.1.4
495 // The server will send this message in response to a ClientHello
496 // message if it is able to find an acceptable set of parameters but the
497 // ClientHello does not contain sufficient information to proceed with
498 // the handshake.
499 //
500 // In this case, the Client Hello did not contain a key share offer for
501 // the group selected by the application.
502 if(!value_exists(offered_by_client, selected_group)) {
503 // RFC 8446 4.1.4
504 // If a client receives a second HelloRetryRequest in the same
505 // connection (i.e., where the ClientHello was itself in response to a
506 // HelloRetryRequest), it MUST abort the handshake with an
507 // "unexpected_message" alert.
508 BOTAN_STATE_CHECK(hello_retry_request_allowed);
509 return Hello_Retry_Request(ch, selected_group, policy, cb);
510 } else {
511 return Server_Hello_13(ch, selected_group, session_mgr, credentials_mgr, rng, cb, policy);
512 }
513}
Server_Hello_13(std::unique_ptr< Server_Hello_Internal > data, Server_Hello_Tag tag=as_server_hello)

References BOTAN_ASSERT_NOMSG, BOTAN_STATE_CHECK, Botan::TLS::Policy::choose_key_exchange_group(), Botan::TLS::Client_Hello::extensions(), Botan::TLS::Server_Hello_13::Server_Hello_13(), and Botan::value_exists().

◆ extension_types()

std::set< Extension_Code > Botan::TLS::Server_Hello::extension_types ( ) const
protectedinherited

Definition at line 222 of file msg_server_hello.cpp.

222 {
223 return m_data->extensions().extension_types();
224}

References Botan::TLS::Server_Hello::m_data.

◆ extensions()

◆ legacy_version()

Protocol_Version Botan::TLS::Server_Hello::legacy_version ( ) const
protectedinherited

Definition at line 202 of file msg_server_hello.cpp.

202 {
203 return m_data->legacy_version();
204}

References Botan::TLS::Server_Hello::m_data.

Referenced by Botan::TLS::Server_Hello_13::basic_validation().

◆ parse()

std::variant< Hello_Retry_Request, Server_Hello_13, Server_Hello_12 > Botan::TLS::Server_Hello_13::parse ( const std::vector< uint8_t > & buf)
staticinherited

Definition at line 515 of file msg_server_hello.cpp.

516 {
517 auto data = std::make_unique<Server_Hello_Internal>(buf);
518 const auto version = data->version();
519
520 // server hello that appears to be pre-TLS 1.3, takes precedence over...
521 if(version.is_pre_tls_13()) {
522 return Server_Hello_12(std::move(data));
523 }
524
525 // ... the TLS 1.3 "special case" aka. Hello_Retry_Request
526 if(version == Protocol_Version::TLS_V13) {
527 if(data->is_hello_retry_request()) {
528 return Hello_Retry_Request(std::move(data));
529 }
530
531 return Server_Hello_13(std::move(data));
532 }
533
534 throw TLS_Exception(Alert::ProtocolVersion, "unexpected server hello version: " + version.to_string());
535}

References Botan::TLS::Server_Hello_13::Server_Hello_13().

◆ random()

const std::vector< uint8_t > & Botan::TLS::Server_Hello::random ( ) const
protectedinherited

Definition at line 206 of file msg_server_hello.cpp.

206 {
207 return m_data->random();
208}

References Botan::TLS::Server_Hello::m_data.

Referenced by Botan::TLS::Server_Hello::serialize().

◆ random_signals_downgrade()

std::optional< Protocol_Version > Botan::TLS::Server_Hello_13::random_signals_downgrade ( ) const
inherited

Return desired downgrade version indicated by hello random, if any.

Definition at line 765 of file msg_server_hello.cpp.

765 {
766 const uint64_t last8 = load_be<uint64_t>(m_data->random().data(), 3);
767 if(last8 == DOWNGRADE_TLS11) {
768 return Protocol_Version::TLS_V11;
769 }
770 if(last8 == DOWNGRADE_TLS12) {
771 return Protocol_Version::TLS_V12;
772 }
773
774 return std::nullopt;
775}
constexpr auto load_be(ParamTs &&... params)
Definition loadstor.h:467

References Botan::load_be(), and Botan::TLS::Server_Hello::m_data.

◆ selected_version()

Protocol_Version Botan::TLS::Server_Hello_13::selected_version ( ) const
finalvirtualinherited
Returns
the selected version as indicated by the supported_versions extension

Implements Botan::TLS::Server_Hello.

Definition at line 777 of file msg_server_hello.cpp.

777 {
778 const auto versions_ext = m_data->extensions().get<Supported_Versions>();
779 BOTAN_ASSERT_NOMSG(versions_ext);
780 const auto& versions = versions_ext->versions();
781 BOTAN_ASSERT_NOMSG(versions.size() == 1);
782 return versions.front();
783}

References BOTAN_ASSERT_NOMSG, and Botan::TLS::Server_Hello::m_data.

Referenced by Botan::TLS::Server_Hello_13::basic_validation().

◆ serialize()

std::vector< uint8_t > Botan::TLS::Server_Hello::serialize ( ) const
overridevirtualinherited
Returns
DER representation of this message

Implements Botan::TLS::Handshake_Message.

Definition at line 178 of file msg_server_hello.cpp.

178 {
179 std::vector<uint8_t> buf;
180 buf.reserve(1024); // working around GCC warning
181
182 buf.push_back(m_data->legacy_version().major_version());
183 buf.push_back(m_data->legacy_version().minor_version());
184 buf += m_data->random();
185
186 append_tls_length_value(buf, m_data->session_id().get(), 1);
187
188 buf.push_back(get_byte<0>(m_data->ciphersuite()));
189 buf.push_back(get_byte<1>(m_data->ciphersuite()));
190
191 buf.push_back(m_data->comp_method());
192
193 buf += m_data->extensions().serialize(Connection_Side::Server);
194
195 return buf;
196}
void append_tls_length_value(std::vector< uint8_t, Alloc > &buf, const T *vals, size_t vals_size, size_t tag_size)
Definition tls_reader.h:180
constexpr uint8_t get_byte(T input)
Definition loadstor.h:75

References Botan::TLS::append_tls_length_value(), Botan::get_byte(), Botan::TLS::Server_Hello::random(), and Botan::TLS::Server.

◆ session_id()

const Session_ID & Botan::TLS::Server_Hello::session_id ( ) const
inherited

Definition at line 214 of file msg_server_hello.cpp.

214 {
215 return m_data->session_id();
216}

References Botan::TLS::Server_Hello::m_data.

◆ type()

Handshake_Type Botan::TLS::Hello_Retry_Request::type ( ) const
inlineoverridevirtual
Returns
the message type

Implements Botan::TLS::Handshake_Message.

Definition at line 460 of file tls_messages.h.

Referenced by Hello_Retry_Request().

◆ type_string()

std::string Botan::TLS::Handshake_Message::type_string ( ) const
inherited
Returns
string representation of this message type

Definition at line 19 of file tls_handshake_state.cpp.

19 {
21}
virtual Handshake_Type type() const =0
const char * handshake_type_to_string(Handshake_Type type)

References Botan::TLS::handshake_type_to_string(), and Botan::TLS::Handshake_Message::type().

◆ wire_type()

Handshake_Type Botan::TLS::Hello_Retry_Request::wire_type ( ) const
inlineoverridevirtual
Returns
the wire representation of the message's type

Reimplemented from Botan::TLS::Handshake_Message.

Definition at line 462 of file tls_messages.h.

Friends And Related Symbol Documentation

◆ Server_Hello_13

friend class Server_Hello_13
friend

Definition at line 455 of file tls_messages.h.

Member Data Documentation

◆ as_hello_retry_request

const Server_Hello_13::Hello_Retry_Request_Tag Botan::TLS::Server_Hello_13::as_hello_retry_request
staticprotectedinherited

Definition at line 456 of file msg_server_hello.cpp.

◆ as_new_hello_retry_request

const Server_Hello_13::Hello_Retry_Request_Creation_Tag Botan::TLS::Server_Hello_13::as_new_hello_retry_request
staticprotectedinherited

Definition at line 457 of file msg_server_hello.cpp.

◆ as_server_hello

const Server_Hello_13::Server_Hello_Tag Botan::TLS::Server_Hello_13::as_server_hello
staticprotectedinherited

Definition at line 455 of file msg_server_hello.cpp.

◆ m_data


The documentation for this class was generated from the following files: