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/*
* Policies for TLS
* (C) 2004-2010,2012 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/tls_policy.h>
#include <botan/tls_ciphersuite.h>
#include <botan/tls_magic.h>
#include <botan/tls_exceptn.h>
#include <botan/internal/stl_util.h>
namespace Botan {
namespace TLS {
std::vector<std::string> Policy::allowed_ciphers() const
{
return std::vector<std::string>({
//"AES-256/OCB(12)",
//"AES-128/OCB(12)",
"ChaCha20Poly1305",
"AES-256/GCM",
"AES-128/GCM",
"AES-256/CCM",
"AES-128/CCM",
"AES-256/CCM-8",
"AES-128/CCM-8",
//"Camellia-256/GCM",
//"Camellia-128/GCM",
"AES-256",
"AES-128",
//"Camellia-256",
//"Camellia-128",
//"SEED"
//"3DES",
//"RC4",
});
}
std::vector<std::string> Policy::allowed_signature_hashes() const
{
return std::vector<std::string>({
"SHA-512",
"SHA-384",
"SHA-256",
"SHA-224",
//"SHA-1",
//"MD5",
});
}
std::vector<std::string> Policy::allowed_macs() const
{
return std::vector<std::string>({
"AEAD",
"SHA-384",
"SHA-256",
"SHA-1",
//"MD5",
});
}
std::vector<std::string> Policy::allowed_key_exchange_methods() const
{
return std::vector<std::string>({
"SRP_SHA",
//"ECDHE_PSK",
//"DHE_PSK",
//"PSK",
"ECDH",
"DH",
"RSA",
});
}
std::vector<std::string> Policy::allowed_signature_methods() const
{
return std::vector<std::string>({
"ECDSA",
"RSA",
"DSA",
//""
});
}
std::vector<std::string> Policy::allowed_ecc_curves() const
{
return std::vector<std::string>({
"brainpool512r1",
"secp521r1",
"brainpool384r1",
"secp384r1",
"brainpool256r1",
"secp256r1",
//"secp256k1",
//"secp224r1",
//"secp224k1",
//"secp192r1",
//"secp192k1",
//"secp160r2",
//"secp160r1",
//"secp160k1",
});
}
/*
* Choose an ECC curve to use
*/
std::string Policy::choose_curve(const std::vector<std::string>& curve_names) const
{
const std::vector<std::string> our_curves = allowed_ecc_curves();
for(size_t i = 0; i != our_curves.size(); ++i)
if(value_exists(curve_names, our_curves[i]))
return our_curves[i];
return ""; // no shared curve
}
DL_Group Policy::dh_group() const
{
return DL_Group("modp/ietf/2048");
}
size_t Policy::minimum_dh_group_size() const
{
return 1024;
}
/*
* Return allowed compression algorithms
*/
std::vector<byte> Policy::compression() const
{
return std::vector<byte>{ NO_COMPRESSION };
}
u32bit Policy::session_ticket_lifetime() const
{
return 86400; // ~1 day
}
bool Policy::send_fallback_scsv(Protocol_Version version) const
{
return version != latest_supported_version(version.is_datagram_protocol());
}
bool Policy::acceptable_protocol_version(Protocol_Version version) const
{
if(version.is_datagram_protocol())
return (version >= Protocol_Version::DTLS_V12);
else
return (version >= Protocol_Version::TLS_V10);
}
Protocol_Version Policy::latest_supported_version(bool datagram) const
{
if(datagram)
return Protocol_Version::latest_dtls_version();
else
return Protocol_Version::latest_tls_version();
}
bool Policy::acceptable_ciphersuite(const Ciphersuite&) const
{
return true;
}
bool Policy::negotiate_heartbeat_support() const
{
return false;
}
bool Policy::allow_server_initiated_renegotiation() const
{
return true;
}
std::vector<u16bit> Policy::srtp_profiles() const
{
return std::vector<u16bit>();
}
namespace {
class Ciphersuite_Preference_Ordering
{
public:
Ciphersuite_Preference_Ordering(const std::vector<std::string>& ciphers,
const std::vector<std::string>& macs,
const std::vector<std::string>& kex,
const std::vector<std::string>& sigs) :
m_ciphers(ciphers), m_macs(macs), m_kex(kex), m_sigs(sigs) {}
bool operator()(const Ciphersuite& a, const Ciphersuite& b) const
{
if(a.kex_algo() != b.kex_algo())
{
for(size_t i = 0; i != m_kex.size(); ++i)
{
if(a.kex_algo() == m_kex[i])
return true;
if(b.kex_algo() == m_kex[i])
return false;
}
}
if(a.cipher_algo() != b.cipher_algo())
{
for(size_t i = 0; i != m_ciphers.size(); ++i)
{
if(a.cipher_algo() == m_ciphers[i])
return true;
if(b.cipher_algo() == m_ciphers[i])
return false;
}
}
if(a.cipher_keylen() != b.cipher_keylen())
{
if(a.cipher_keylen() < b.cipher_keylen())
return false;
if(a.cipher_keylen() > b.cipher_keylen())
return true;
}
if(a.sig_algo() != b.sig_algo())
{
for(size_t i = 0; i != m_sigs.size(); ++i)
{
if(a.sig_algo() == m_sigs[i])
return true;
if(b.sig_algo() == m_sigs[i])
return false;
}
}
if(a.mac_algo() != b.mac_algo())
{
for(size_t i = 0; i != m_macs.size(); ++i)
{
if(a.mac_algo() == m_macs[i])
return true;
if(b.mac_algo() == m_macs[i])
return false;
}
}
return false; // equal (?!?)
}
private:
std::vector<std::string> m_ciphers, m_macs, m_kex, m_sigs;
};
}
std::vector<u16bit> Policy::ciphersuite_list(Protocol_Version version,
bool have_srp) const
{
const std::vector<std::string> ciphers = allowed_ciphers();
const std::vector<std::string> macs = allowed_macs();
const std::vector<std::string> kex = allowed_key_exchange_methods();
const std::vector<std::string> sigs = allowed_signature_methods();
Ciphersuite_Preference_Ordering order(ciphers, macs, kex, sigs);
std::set<Ciphersuite, Ciphersuite_Preference_Ordering> ciphersuites(order);
for(auto&& suite : Ciphersuite::all_known_ciphersuites())
{
if(!acceptable_ciphersuite(suite))
continue;
if(!have_srp && suite.kex_algo() == "SRP_SHA")
continue;
if(version.is_datagram_protocol() && suite.cipher_algo() == "RC4")
continue;
if(!version.supports_aead_modes() && suite.mac_algo() == "AEAD")
continue;
if(!value_exists(kex, suite.kex_algo()))
continue; // unsupported key exchange
if(!value_exists(ciphers, suite.cipher_algo()))
continue; // unsupported cipher
if(!value_exists(macs, suite.mac_algo()))
continue; // unsupported MAC algo
if(!value_exists(sigs, suite.sig_algo()))
{
// allow if it's an empty sig algo and we want to use PSK
if(suite.sig_algo() != "" || !suite.psk_ciphersuite())
continue;
}
// OK, allow it:
ciphersuites.insert(suite);
}
if(ciphersuites.empty())
throw std::logic_error("Policy does not allow any available cipher suite");
std::vector<u16bit> ciphersuite_codes;
for(auto i : ciphersuites)
ciphersuite_codes.push_back(i.ciphersuite_code());
return ciphersuite_codes;
}
}
}
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