Botan 2.19.3
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#include <botan/mac.h>
10
11namespace Botan {
12
13namespace TLS {
14
15Hello_Verify_Request::Hello_Verify_Request(const std::vector<uint8_t>& buf)
16 {
17 if(buf.size() < 3)
18 throw Decoding_Error("Hello verify request too small");
19
20 Protocol_Version version(buf[0], buf[1]);
21
22 if(version != Protocol_Version::DTLS_V10 &&
24 {
25 throw Decoding_Error("Unknown version from server in hello verify request");
26 }
27
28 if(static_cast<size_t>(buf[2]) + 3 != buf.size())
29 throw Decoding_Error("Bad length in hello verify request");
30
31 m_cookie.assign(buf.begin() + 3, buf.end());
32 }
33
34Hello_Verify_Request::Hello_Verify_Request(const std::vector<uint8_t>& client_hello_bits,
35 const std::string& client_identity,
36 const SymmetricKey& secret_key)
37 {
38 std::unique_ptr<MessageAuthenticationCode> hmac = MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
39 hmac->set_key(secret_key);
40
41 hmac->update_be(static_cast<uint64_t>(client_hello_bits.size()));
42 hmac->update(client_hello_bits);
43 hmac->update_be(static_cast<uint64_t>(client_identity.size()));
44 hmac->update(client_identity);
45
46 m_cookie.resize(hmac->output_length());
47 hmac->final(m_cookie.data());
48 }
49
50std::vector<uint8_t> Hello_Verify_Request::serialize() const
51 {
52 /* DTLS 1.2 server implementations SHOULD use DTLS version 1.0
53 regardless of the version of TLS that is expected to be
54 negotiated (RFC 6347, section 4.2.1)
55 */
56
58
59 std::vector<uint8_t> bits;
60 bits.push_back(format_version.major_version());
61 bits.push_back(format_version.minor_version());
62 bits.push_back(static_cast<uint8_t>(m_cookie.size()));
63 bits += m_cookie;
64 return bits;
65 }
66
67}
68
69}
static std::unique_ptr< MessageAuthenticationCode > create_or_throw(const std::string &algo_spec, const std::string &provider="")
Definition mac.cpp:139
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:79
uint8_t minor_version() const
Definition tls_version.h:84