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/*
* TLS Cipher Suite
* (C) 2004-2010,2012,2013 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/tls_ciphersuite.h>
#include <botan/exceptn.h>
#include <botan/parsing.h>
#include <botan/block_cipher.h>
#include <botan/stream_cipher.h>
#include <botan/hash.h>
#include <algorithm>
namespace Botan {
namespace TLS {
size_t Ciphersuite::nonce_bytes_from_handshake() const
{
switch(m_nonce_format)
{
case Nonce_Format::CBC_MODE:
{
if(cipher_algo() == "3DES")
return 8;
else
return 16;
}
case Nonce_Format::AEAD_IMPLICIT_4:
return 4;
case Nonce_Format::AEAD_XOR_12:
return 12;
}
throw Invalid_State("In Ciphersuite::nonce_bytes_from_handshake invalid enum value");
}
size_t Ciphersuite::nonce_bytes_from_record(Protocol_Version version) const
{
switch(m_nonce_format)
{
case Nonce_Format::CBC_MODE:
{
if(version.supports_explicit_cbc_ivs())
{
return cipher_algo() == "3DES" ? 8 : 16;
}
else
{
return 0;
}
}
case Nonce_Format::AEAD_IMPLICIT_4:
return 8;
case Nonce_Format::AEAD_XOR_12:
return 0;
}
throw Invalid_State("In Ciphersuite::nonce_bytes_from_handshake invalid enum value");
}
bool Ciphersuite::is_scsv(uint16_t suite)
{
// TODO: derive from IANA file in script
return (suite == 0x00FF || suite == 0x5600);
}
bool Ciphersuite::psk_ciphersuite() const
{
return kex_method() == Kex_Algo::PSK ||
kex_method() == Kex_Algo::DHE_PSK ||
kex_method() == Kex_Algo::ECDHE_PSK;
}
bool Ciphersuite::ecc_ciphersuite() const
{
return kex_method() == Kex_Algo::ECDH ||
kex_method() == Kex_Algo::ECDHE_PSK ||
auth_method() == Auth_Method::ECDSA;
}
bool Ciphersuite::usable_in_version(Protocol_Version version) const
{
if(!version.supports_aead_modes())
{
// Old versions do not support AEAD, or any MAC but SHA-1
if(mac_algo() != "SHA-1")
return false;
}
return true;
}
bool Ciphersuite::cbc_ciphersuite() const
{
return (mac_algo() != "AEAD");
}
bool Ciphersuite::signature_used() const
{
return auth_method() != Auth_Method::ANONYMOUS &&
auth_method() != Auth_Method::IMPLICIT;
}
Ciphersuite Ciphersuite::by_id(uint16_t suite)
{
const std::vector<Ciphersuite>& all_suites = all_known_ciphersuites();
auto s = std::lower_bound(all_suites.begin(), all_suites.end(), suite);
if(s != all_suites.end() && s->ciphersuite_code() == suite)
{
return *s;
}
return Ciphersuite(); // some unknown ciphersuite
}
Ciphersuite Ciphersuite::from_name(const std::string& name)
{
const std::vector<Ciphersuite>& all_suites = all_known_ciphersuites();
for(auto suite : all_suites)
{
if(suite.to_string() == name)
return suite;
}
return Ciphersuite(); // some unknown ciphersuite
}
namespace {
bool have_hash(const std::string& prf)
{
return (HashFunction::providers(prf).size() > 0);
}
bool have_cipher(const std::string& cipher)
{
return (BlockCipher::providers(cipher).size() > 0) ||
(StreamCipher::providers(cipher).size() > 0);
}
}
bool Ciphersuite::is_usable() const
{
if(!m_cipher_keylen) // uninitialized object
return false;
if(!have_hash(prf_algo()))
return false;
#if !defined(BOTAN_HAS_TLS_CBC)
if(cbc_ciphersuite())
return false;
#endif
if(mac_algo() == "AEAD")
{
if(cipher_algo() == "ChaCha20Poly1305")
{
#if !defined(BOTAN_HAS_AEAD_CHACHA20_POLY1305)
return false;
#endif
}
else
{
auto cipher_and_mode = split_on(cipher_algo(), '/');
BOTAN_ASSERT(cipher_and_mode.size() == 2, "Expected format for AEAD algo");
if(!have_cipher(cipher_and_mode[0]))
return false;
const auto mode = cipher_and_mode[1];
#if !defined(BOTAN_HAS_AEAD_CCM)
if(mode == "CCM" || mode == "CCM-8")
return false;
#endif
#if !defined(BOTAN_HAS_AEAD_GCM)
if(mode == "GCM")
return false;
#endif
#if !defined(BOTAN_HAS_AEAD_OCB)
if(mode == "OCB(12)" || mode == "OCB")
return false;
#endif
}
}
else
{
// Old non-AEAD schemes
if(!have_cipher(cipher_algo()))
return false;
if(!have_hash(mac_algo())) // HMAC
return false;
}
if(kex_method() == Kex_Algo::SRP_SHA)
{
#if !defined(BOTAN_HAS_SRP6)
return false;
#endif
}
else if(kex_method() == Kex_Algo::ECDH || kex_method() == Kex_Algo::ECDHE_PSK)
{
#if !defined(BOTAN_HAS_ECDH)
return false;
#endif
}
else if(kex_method() == Kex_Algo::DH || kex_method() == Kex_Algo::DHE_PSK)
{
#if !defined(BOTAN_HAS_DIFFIE_HELLMAN)
return false;
#endif
}
else if(kex_method() == Kex_Algo::CECPQ1)
{
#if !defined(BOTAN_HAS_CECPQ1)
return false;
#endif
}
if(auth_method() == Auth_Method::DSA)
{
#if !defined(BOTAN_HAS_DSA)
return false;
#endif
}
else if(auth_method() == Auth_Method::ECDSA)
{
#if !defined(BOTAN_HAS_ECDSA)
return false;
#endif
}
else if(auth_method() == Auth_Method::RSA)
{
#if !defined(BOTAN_HAS_RSA)
return false;
#endif
}
return true;
}
}
}