Botan 3.3.0
Crypto and TLS for C&
msg_hello_verify.cpp
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1/*
2* DTLS Hello Verify Request
3* (C) 2012 Jack Lloyd
4*
5* Botan is released under the Simplified BSD License (see license.txt)
6*/
7
8#include <botan/tls_messages.h>
9
10#include <botan/mac.h>
11
12namespace Botan::TLS {
13
14Hello_Verify_Request::Hello_Verify_Request(const std::vector<uint8_t>& buf) {
15 if(buf.size() < 3) {
16 throw Decoding_Error("Hello verify request too small");
17 }
18
19 Protocol_Version version(buf[0], buf[1]);
20
21 if(!version.is_datagram_protocol()) {
22 throw Decoding_Error("Unknown version from server in hello verify request");
23 }
24
25 if(static_cast<size_t>(buf[2]) + 3 != buf.size()) {
26 throw Decoding_Error("Bad length in hello verify request");
27 }
28
29 m_cookie.assign(buf.begin() + 3, buf.end());
30}
31
32Hello_Verify_Request::Hello_Verify_Request(const std::vector<uint8_t>& client_hello_bits,
33 std::string_view client_identity,
34 const SymmetricKey& secret_key) {
35 auto hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
36 hmac->set_key(secret_key);
37
38 hmac->update_be(static_cast<uint64_t>(client_hello_bits.size()));
39 hmac->update(client_hello_bits);
40 hmac->update_be(static_cast<uint64_t>(client_identity.size()));
41 hmac->update(client_identity);
42
43 m_cookie.resize(hmac->output_length());
44 hmac->final(m_cookie.data());
45}
46
47std::vector<uint8_t> Hello_Verify_Request::serialize() const {
48 /* DTLS 1.2 server implementations SHOULD use DTLS version 1.0
49 regardless of the version of TLS that is expected to be
50 negotiated (RFC 6347, section 4.2.1)
51 */
52
53 Protocol_Version format_version(254, 255); // DTLS 1.0
54
55 std::vector<uint8_t> bits;
56 bits.push_back(format_version.major_version());
57 bits.push_back(format_version.minor_version());
58 bits.push_back(static_cast<uint8_t>(m_cookie.size()));
59 bits += m_cookie;
60 return bits;
61}
62
63} // namespace Botan::TLS
static std::unique_ptr< MessageAuthenticationCode > create_or_throw(std::string_view algo_spec, std::string_view provider="")
Definition mac.cpp:148
Hello_Verify_Request(const std::vector< uint8_t > &buf)
std::vector< uint8_t > serialize() const override
uint8_t major_version() const
Definition tls_version.h:78
uint8_t minor_version() const
Definition tls_version.h:83