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/*
* Policies for TLS
* (C) 2004-2010,2012,2015,2016 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 {
//"AES-256/OCB(12)",
//"AES-128/OCB(12)",
"AES-256/GCM",
"AES-128/GCM",
"ChaCha20Poly1305",
"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",
};
}
std::vector<std::string> Policy::allowed_signature_hashes() const
{
return {
"SHA-512",
"SHA-384",
"SHA-256",
//"SHA-1",
};
}
std::vector<std::string> Policy::allowed_macs() const
{
return {
"AEAD",
"SHA-384",
"SHA-256",
"SHA-1",
};
}
std::vector<std::string> Policy::allowed_key_exchange_methods() const
{
return {
//"SRP_SHA",
//"ECDHE_PSK",
//"DHE_PSK",
//"PSK",
"ECDH",
"DH",
"RSA",
};
}
std::vector<std::string> Policy::allowed_signature_methods() const
{
return {
"ECDSA",
"RSA",
"DSA",
//"" (anon)
};
}
bool Policy::allowed_signature_method(const std::string& sig_method) const
{
return value_exists(allowed_signature_methods(), sig_method);
}
std::vector<std::string> Policy::allowed_ecc_curves() const
{
return {
"brainpool512r1",
"secp521r1",
"brainpool384r1",
"secp384r1",
"brainpool256r1",
"secp256r1",
};
}
bool Policy::allowed_ecc_curve(const std::string& curve) const
{
return value_exists(allowed_ecc_curves(), curve);
}
/*
* 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
}
std::string Policy::dh_group() const
{
return "modp/ietf/2048";
}
size_t Policy::minimum_dh_group_size() const
{
return 1024;
}
size_t Policy::minimum_ecdh_group_size() const
{
return 159;
}
size_t Policy::minimum_rsa_bits() const
{
return 1000; // Not 1024, since some certificates use, e.g., only 1023 bits
}
/*
* 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
{
// Uses boolean optimization:
// First check the current version (left part), then if it is allowed
// (right part)
// checks are ordered according to their probability
return (
( ( version == Protocol_Version::TLS_V10) && allow_tls10() ) ||
( ( version == Protocol_Version::TLS_V12) && allow_tls12() ) ||
( ( version == Protocol_Version::TLS_V11) && allow_tls11() ) ||
( ( version == Protocol_Version::DTLS_V12) && allow_dtls12() ) ||
( ( version == Protocol_Version::DTLS_V10) && allow_dtls10() )
);
}
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::allow_server_initiated_renegotiation() const { return false; }
bool Policy::allow_insecure_renegotiation() const { return false; }
bool Policy::allow_tls10() const { return true; }
bool Policy::allow_tls11() const { return true; }
bool Policy::allow_tls12() const { return true; }
bool Policy::allow_dtls10() const { return false; }
bool Policy::allow_dtls12() const { return true; }
bool Policy::include_time_in_hello_random() const { return true; }
bool Policy::hide_unknown_users() const { return false; }
bool Policy::server_uses_own_ciphersuite_preferences() const { return true; }
bool Policy::negotiate_encrypt_then_mac() const { return true; }
// 1 second initial timeout, 60 second max - see RFC 6347 sec 4.2.4.1
size_t Policy::dtls_initial_timeout() const { return 1*1000; }
size_t Policy::dtls_maximum_timeout() const { return 60*1000; }
size_t Policy::dtls_default_mtu() const
{
// default MTU is IPv6 min MTU minus UDP/IP headers
return 1280 - 40 - 8;
}
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();
std::vector<Ciphersuite> ciphersuites;
for(auto&& suite : Ciphersuite::all_known_ciphersuites())
{
if(!acceptable_ciphersuite(suite))
continue;
if(!have_srp && suite.kex_algo() == "SRP_SHA")
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, consider it
ciphersuites.push_back(suite);
}
if(ciphersuites.empty())
throw Exception("Policy does not allow any available cipher suite");
Ciphersuite_Preference_Ordering order(ciphers, macs, kex, sigs);
std::sort(ciphersuites.begin(), ciphersuites.end(), order);
std::vector<u16bit> ciphersuite_codes;
for(auto i : ciphersuites)
ciphersuite_codes.push_back(i.ciphersuite_code());
return ciphersuite_codes;
}
namespace {
void print_vec(std::ostream& o,
const char* key,
const std::vector<std::string>& v)
{
o << key << " = ";
for(size_t i = 0; i != v.size(); ++i)
{
o << v[i];
if(i != v.size() - 1)
o << ' ';
}
o << '\n';
}
void print_bool(std::ostream& o,
const char* key, bool b)
{
o << key << " = " << (b ? "true" : "false") << '\n';
}
}
void Policy::print(std::ostream& o) const
{
print_bool(o, "allow_tls10", allow_tls10());
print_bool(o, "allow_tls11", allow_tls11());
print_bool(o, "allow_tls12", allow_tls12());
print_bool(o, "allow_dtls10", allow_dtls10());
print_bool(o, "allow_dtls12", allow_dtls12());
print_vec(o, "ciphers", allowed_ciphers());
print_vec(o, "macs", allowed_macs());
print_vec(o, "signature_hashes", allowed_signature_hashes());
print_vec(o, "signature_methods", allowed_signature_methods());
print_vec(o, "key_exchange_methods", allowed_key_exchange_methods());
print_vec(o, "ecc_curves", allowed_ecc_curves());
print_bool(o, "allow_insecure_renegotiation", allow_insecure_renegotiation());
print_bool(o, "include_time_in_hello_random", include_time_in_hello_random());
print_bool(o, "allow_server_initiated_renegotiation", allow_server_initiated_renegotiation());
print_bool(o, "hide_unknown_users", hide_unknown_users());
print_bool(o, "server_uses_own_ciphersuite_preferences", server_uses_own_ciphersuite_preferences());
print_bool(o, "negotiate_encrypt_then_mac", negotiate_encrypt_then_mac());
o << "session_ticket_lifetime = " << session_ticket_lifetime() << '\n';
o << "dh_group = " << dh_group() << '\n';
o << "minimum_dh_group_size = " << minimum_dh_group_size() << '\n';
o << "minimum_ecdh_group_size = " << minimum_ecdh_group_size() << '\n';
o << "minimum_rsa_bits = " << minimum_rsa_bits() << '\n';
}
std::vector<std::string> Strict_Policy::allowed_ciphers() const
{
return { "ChaCha20Poly1305", "AES-256/GCM", "AES-128/GCM" };
}
std::vector<std::string> Strict_Policy::allowed_signature_hashes() const
{
return { "SHA-512", "SHA-384"};
}
std::vector<std::string> Strict_Policy::allowed_macs() const
{
return { "AEAD" };
}
std::vector<std::string> Strict_Policy::allowed_key_exchange_methods() const
{
return { "ECDH" };
}
bool Strict_Policy::allow_tls10() const { return false; }
bool Strict_Policy::allow_tls11() const { return false; }
bool Strict_Policy::allow_tls12() const { return true; }
bool Strict_Policy::allow_dtls10() const { return false; }
bool Strict_Policy::allow_dtls12() const { return true; }
}
}
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