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/*
* Policies for TLS
* (C) 2004-2010,2012 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#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>
#include <set>
namespace Botan {
namespace TLS {
std::vector<std::string> Policy::allowed_ciphers() const
{
return std::vector<std::string>({
"ARC4",
"AES-128",
"AES-256",
//"3DES",
//"Camellia-256",
//"Camellia-128",
//"SEED"
});
}
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>({
"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>({
"secp521r1",
"secp384r1",
"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::acceptable_protocol_version(Protocol_Version version) const
{
return version.known_version(); // accept any version we know about
// maybe someday...
//return version >= Protocol_Version::TLS_V11;
}
bool Policy::server_uses_own_ciphersuite_preferences() const
{
return true;
}
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> ciphersuite_list(const Policy& policy,
Protocol_Version version,
bool have_srp)
{
const std::vector<std::string> ciphers = policy.allowed_ciphers();
const std::vector<std::string> macs = policy.allowed_macs();
const std::vector<std::string> kex = policy.allowed_key_exchange_methods();
const std::vector<std::string> sigs = policy.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(!have_srp && suite.kex_algo() == "SRP_SHA")
continue;
if(version.is_datagram_protocol() && suite.cipher_algo() == "ARC4")
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);
}
std::vector<u16bit> ciphersuite_codes;
for(auto i : ciphersuites)
ciphersuite_codes.push_back(i.ciphersuite_code());
return ciphersuite_codes;
}
}
}
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