20300409060

Committed 17 Dec 2025 10:55AM UTC coverage: 90.526% (+0.2%) from 90.36%

Build # 20300409060

Build Type

Pull #5167

github

Committed by

web-flow

Commit Message

Merge b37a2cfb3 into 3d96b675e

Pull Request Pull Request #5167: Changes to reduce unnecessary inclusions

Run Details

101175 of 111763 relevant lines covered (90.53%)

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94.59

/src/lib/tls/tls13/msg_encrypted_extensions.cpp

/*
* TLS Hello Request and Client Hello Messages
* (C) 2022 Jack Lloyd
*     2022 René Meusel, Hannes Rantzsch - neXenio GmbH
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/tls_messages.h>

#include <botan/tls_callbacks.h>
#include <botan/tls_exceptn.h>
#include <botan/tls_policy.h>
#include <botan/internal/tls_reader.h>

namespace Botan::TLS {

Encrypted_Extensions::Encrypted_Extensions(const Client_Hello_13& client_hello, const Policy& policy, Callbacks& cb) {
   const auto& exts = client_hello.extensions();

   // NOLINTBEGIN(*-owning-memory)

   // RFC 8446 4.2.7
   //    As of TLS 1.3, servers are permitted to send the "supported_groups"
   //    extension to the client.  Clients [...] MAY use the information
   //    learned from a successfully completed handshake to change what groups
   //    they use in their "key_share" extension in subsequent connections.
   if(exts.has<Supported_Groups>()) {
      m_extensions.add(new Supported_Groups(policy.key_exchange_groups()));
   }

   const auto record_size_limit = policy.record_size_limit();
   const auto max_record_size = MAX_PLAINTEXT_SIZE + 1 /* encrypted content type byte */;
   if(exts.has<Record_Size_Limit>()) {
      // RFC 8449 4
      //    Endpoints SHOULD advertise the "record_size_limit" extension, even
      //    if they have no need to limit the size of records. [...]  For
      //    servers, this allows clients to know that their limit will be
      //    respected.
      m_extensions.add(new Record_Size_Limit(record_size_limit.value_or(max_record_size)));
   } else if(record_size_limit.has_value() && record_size_limit.value() < max_record_size) {
      // RFC 8449 4
      //    Endpoints SHOULD advertise the "record_size_limit" extension, even if
      //    they have no need to limit the size of records. For clients, this
      //    allows servers to advertise a limit at their discretion.
      throw TLS_Exception(Alert::MissingExtension,
                          "Server cannot enforce record size limit without the client supporting it");
   }

   // RFC 7250 4.2
   //    If the TLS server wants to request a certificate from the client
   //    (via the certificate_request message), it MUST include the
   //    client_certificate_type extension in the server hello.
   //    [...]
   //    If the server does not send a certificate_request payload [...],
   //    then the client_certificate_type payload in the server hello MUST be
   //    omitted.
   if(auto* ch_client_cert_types = exts.get<Client_Certificate_Type>();
      ch_client_cert_types != nullptr && policy.request_client_certificate_authentication()) {
      m_extensions.add(new Client_Certificate_Type(*ch_client_cert_types, policy));
   }

   // RFC 7250 4.2
   //    The server_certificate_type extension in the client hello indicates the
   //    types of certificates the client is able to process when provided by
   //    the server in a subsequent certificate payload. [...] With the
   //    server_certificate_type extension in the server hello, the TLS server
   //    indicates the certificate type carried in the Certificate payload.
   if(auto* ch_server_cert_types = exts.get<Server_Certificate_Type>()) {
      m_extensions.add(new Server_Certificate_Type(*ch_server_cert_types, policy));
   }

   // RFC 6066 3
   //    A server that receives a client hello containing the "server_name"
   //    extension [...] SHALL include an extension of type "server_name" in the
   //    (extended) server hello. The "extension_data" field of this extension
   //    SHALL be empty.
   if(exts.has<Server_Name_Indicator>()) {
      m_extensions.add(new Server_Name_Indicator(""));
   }

   if(auto* alpn_ext = exts.get<Application_Layer_Protocol_Notification>()) {
      const auto next_protocol = cb.tls_server_choose_app_protocol(alpn_ext->protocols());
      if(!next_protocol.empty()) {
         m_extensions.add(new Application_Layer_Protocol_Notification(next_protocol));
      }
   }

   // NOLINTEND(*-owning-memory)

   // TODO: Implement handling for (at least)
   //       * SRTP

   cb.tls_modify_extensions(m_extensions, Connection_Side::Server, type());
}

Encrypted_Extensions::Encrypted_Extensions(const std::vector<uint8_t>& buf) {
   TLS_Data_Reader reader("encrypted extensions reader", buf);

   // Encrypted Extensions contains a list of extensions. This list may legally
   // be empty. However, in that case we should at least see a two-byte length
   // field that reads 0x00 0x00.
   if(buf.size() < 2) {
      throw TLS_Exception(Alert::DecodeError, "Server sent an empty Encrypted Extensions message");
   }

   m_extensions.deserialize(reader, Connection_Side::Server, type());

   // RFC 8446 4.2
   //    If an implementation receives an extension which it recognizes and
   //    which is not specified for the message in which it appears, it MUST
   //    abort the handshake with an "illegal_parameter" alert.
   //
   // Note that we cannot encounter any extensions that we don't recognize here,
   // since only extensions we previously offered are allowed in EE.
   const auto allowed_exts = std::set<Extension_Code>{
      // Allowed extensions listed in RFC 8446 and implemented in Botan
      Extension_Code::ServerNameIndication,
      // MAX_FRAGMENT_LENGTH
      Extension_Code::SupportedGroups,
      Extension_Code::UseSrtp,
      // HEARTBEAT
      Extension_Code::ApplicationLayerProtocolNegotiation,
      // RFC 7250
      Extension_Code::ClientCertificateType,
      Extension_Code::ServerCertificateType,
      // EARLY_DATA

      // Allowed extensions not listed in RFC 8446 but acceptable as Botan implements them
      Extension_Code::RecordSizeLimit,
   };
   if(m_extensions.contains_implemented_extensions_other_than(allowed_exts)) {
      throw TLS_Exception(Alert::IllegalParameter, "Encrypted Extensions contained an extension that is not allowed");
   }
}

std::vector<uint8_t> Encrypted_Extensions::serialize() const {
   return m_extensions.serialize(Connection_Side::Server);
}

}  // namespace Botan::TLS

1	/*
2	* TLS Hello Request and Client Hello Messages
3	* (C) 2022 Jack Lloyd
4	* 2022 René Meusel, Hannes Rantzsch - neXenio GmbH
5	*
6	* Botan is released under the Simplified BSD License (see license.txt)
7	*/
8
9	#include <botan/tls_messages.h>
10
11	#include <botan/tls_callbacks.h>
12	#include <botan/tls_exceptn.h>
13	#include <botan/tls_policy.h>
14	#include <botan/internal/tls_reader.h>
15
16	namespace Botan::TLS {
17
18	Encrypted_Extensions::Encrypted_Extensions(const Client_Hello_13& client_hello, const Policy& policy, Callbacks& cb) {	363✔
19	const auto& exts = client_hello.extensions();	363✔
20
21	// NOLINTBEGIN(*-owning-memory)
22
23	// RFC 8446 4.2.7
24	// As of TLS 1.3, servers are permitted to send the "supported_groups"
25	// extension to the client. Clients [...] MAY use the information
26	// learned from a successfully completed handshake to change what groups
27	// they use in their "key_share" extension in subsequent connections.
28	if(exts.has<Supported_Groups>()) {	363✔
29	m_extensions.add(new Supported_Groups(policy.key_exchange_groups()));	726✔
30	}
31
32	const auto record_size_limit = policy.record_size_limit();	363✔
33	const auto max_record_size = MAX_PLAINTEXT_SIZE + 1 /* encrypted content type byte */;	363✔
34	if(exts.has<Record_Size_Limit>()) {	363✔
35	// RFC 8449 4
36	// Endpoints SHOULD advertise the "record_size_limit" extension, even
37	// if they have no need to limit the size of records. [...] For
38	// servers, this allows clients to know that their limit will be
39	// respected.
40	m_extensions.add(new Record_Size_Limit(record_size_limit.value_or(max_record_size)));	15✔
41	} else if(record_size_limit.has_value() && record_size_limit.value() < max_record_size) {	355✔
42	// RFC 8449 4
43	// Endpoints SHOULD advertise the "record_size_limit" extension, even if
44	// they have no need to limit the size of records. For clients, this
45	// allows servers to advertise a limit at their discretion.
46	throw TLS_Exception(Alert::MissingExtension,	×
47	"Server cannot enforce record size limit without the client supporting it");	×
48	}
49
50	// RFC 7250 4.2
51	// If the TLS server wants to request a certificate from the client
52	// (via the certificate_request message), it MUST include the
53	// client_certificate_type extension in the server hello.
54	// [...]
55	// If the server does not send a certificate_request payload [...],
56	// then the client_certificate_type payload in the server hello MUST be
57	// omitted.
58	if(auto* ch_client_cert_types = exts.get<Client_Certificate_Type>();	363✔
59	ch_client_cert_types != nullptr && policy.request_client_certificate_authentication()) {	363✔
60	m_extensions.add(new Client_Certificate_Type(*ch_client_cert_types, policy));	1✔
61	}
62
63	// RFC 7250 4.2
64	// The server_certificate_type extension in the client hello indicates the
65	// types of certificates the client is able to process when provided by
66	// the server in a subsequent certificate payload. [...] With the
67	// server_certificate_type extension in the server hello, the TLS server
68	// indicates the certificate type carried in the Certificate payload.
69	if(auto* ch_server_cert_types = exts.get<Server_Certificate_Type>()) {	363✔
70	m_extensions.add(new Server_Certificate_Type(*ch_server_cert_types, policy));	1✔
71	}
72
73	// RFC 6066 3
74	// A server that receives a client hello containing the "server_name"
75	// extension [...] SHALL include an extension of type "server_name" in the
76	// (extended) server hello. The "extension_data" field of this extension
77	// SHALL be empty.
78	if(exts.has<Server_Name_Indicator>()) {	363✔
79	m_extensions.add(new Server_Name_Indicator(""));	354✔
80	}
81
82	if(auto* alpn_ext = exts.get<Application_Layer_Protocol_Notification>()) {	363✔
83	const auto next_protocol = cb.tls_server_choose_app_protocol(alpn_ext->protocols());	7✔
84	if(!next_protocol.empty()) {	6✔
85	m_extensions.add(new Application_Layer_Protocol_Notification(next_protocol));	4✔
86	}
87	}	6✔
88
89	// NOLINTEND(*-owning-memory)
90
91	// TODO: Implement handling for (at least)
92	// * SRTP
93
94	cb.tls_modify_extensions(m_extensions, Connection_Side::Server, type());	362✔
95	}	363✔
96
97	Encrypted_Extensions::Encrypted_Extensions(const std::vector<uint8_t>& buf) {	431✔
98	TLS_Data_Reader reader("encrypted extensions reader", buf);	431✔
99
100	// Encrypted Extensions contains a list of extensions. This list may legally
101	// be empty. However, in that case we should at least see a two-byte length
102	// field that reads 0x00 0x00.
103	if(buf.size() < 2) {	431✔
104	throw TLS_Exception(Alert::DecodeError, "Server sent an empty Encrypted Extensions message");	1✔
105	}
106
107	m_extensions.deserialize(reader, Connection_Side::Server, type());	430✔
108
109	// RFC 8446 4.2
110	// If an implementation receives an extension which it recognizes and
111	// which is not specified for the message in which it appears, it MUST
112	// abort the handshake with an "illegal_parameter" alert.
113	//
114	// Note that we cannot encounter any extensions that we don't recognize here,
115	// since only extensions we previously offered are allowed in EE.
116	const auto allowed_exts = std::set<Extension_Code>{	426✔
117	// Allowed extensions listed in RFC 8446 and implemented in Botan
118	Extension_Code::ServerNameIndication,
119	// MAX_FRAGMENT_LENGTH
120	Extension_Code::SupportedGroups,
121	Extension_Code::UseSrtp,
122	// HEARTBEAT
123	Extension_Code::ApplicationLayerProtocolNegotiation,
124	// RFC 7250
125	Extension_Code::ClientCertificateType,
126	Extension_Code::ServerCertificateType,
127	// EARLY_DATA
128
129	// Allowed extensions not listed in RFC 8446 but acceptable as Botan implements them
130	Extension_Code::RecordSizeLimit,
131	};	426✔
132	if(m_extensions.contains_implemented_extensions_other_than(allowed_exts)) {	426✔
133	throw TLS_Exception(Alert::IllegalParameter, "Encrypted Extensions contained an extension that is not allowed");	5✔
134	}
135	}	431✔
136
137	std::vector<uint8_t> Encrypted_Extensions::serialize() const {	375✔
138	return m_extensions.serialize(Connection_Side::Server);	375✔
139	}
140
141	} // namespace Botan::TLS

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