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/*
* ECDSA and ECDH via OpenSSL
* (C) 2015,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/openssl.h>
#if defined(BOTAN_HAS_ECC_PUBLIC_KEY_CRYPTO)
#include <botan/der_enc.h>
#include <botan/pkcs8.h>
#include <botan/oids.h>
#include <botan/internal/pk_ops_impl.h>
#endif
#if defined(BOTAN_HAS_ECDSA)
#include <botan/ecdsa.h>
#endif
#if defined(BOTAN_HAS_ECDH)
#include <botan/ecdh.h>
#endif
#include <openssl/x509.h>
#include <openssl/objects.h>
#if !defined(OPENSSL_NO_EC)
#include <openssl/ec.h>
#endif
#if !defined(OPENSSL_NO_ECDSA)
#include <openssl/ecdsa.h>
#endif
#if !defined(OPENSSL_NO_ECDH)
#include <openssl/ecdh.h>
#endif
namespace Botan {
#if defined(BOTAN_HAS_ECC_PUBLIC_KEY_CRYPTO)
namespace {
secure_vector<uint8_t> PKCS8_for_openssl(const EC_PrivateKey& ec)
{
const PointGFp& pub_key = ec.public_point();
const BigInt& priv_key = ec.private_value();
return DER_Encoder()
.start_cons(SEQUENCE)
.encode(static_cast<size_t>(1))
.encode(BigInt::encode_1363(priv_key, priv_key.bytes()), OCTET_STRING)
.start_cons(ASN1_Tag(0), PRIVATE)
.raw_bytes(ec.domain().DER_encode(EC_DOMPAR_ENC_OID))
.end_cons()
.start_cons(ASN1_Tag(1), PRIVATE)
.encode(EC2OSP(pub_key, PointGFp::UNCOMPRESSED), BIT_STRING)
.end_cons()
.end_cons()
.get_contents();
}
int OpenSSL_EC_nid_for(const EC_Group& group)
{
if(group == EC_Group("secp192r1"))
return NID_X9_62_prime192v1;
if(group == EC_Group("secp224r1"))
return NID_secp224r1;
if(group == EC_Group("secp256r1"))
return NID_X9_62_prime256v1;
if(group == EC_Group("secp384r1"))
return NID_secp384r1;
if(group == EC_Group("secp521r1"))
return NID_secp521r1;
// OpenSSL 1.0.2 added brainpool curves
#if OPENSSL_VERSION_NUMBER >= 0x1000200fL
if(group == EC_Group("brainpool160r1"))
return NID_brainpoolP160r1;
if(group == EC_Group("brainpool192r1"))
return NID_brainpoolP192r1;
if(group == EC_Group("brainpool224r1"))
return NID_brainpoolP224r1;
if(group == EC_Group("brainpool256r1"))
return NID_brainpoolP256r1;
if(group == EC_Group("brainpool320r1"))
return NID_brainpoolP320r1;
if(group == EC_Group("brainpool384r1"))
return NID_brainpoolP384r1;
if(group == EC_Group("brainpool512r1"))
return NID_brainpoolP512r1;
#endif
return -1;
}
}
#endif
#if defined(BOTAN_HAS_ECDSA) && !defined(OPENSSL_NO_ECDSA)
namespace {
class OpenSSL_ECDSA_Verification_Operation : public PK_Ops::Verification_with_EMSA
{
public:
OpenSSL_ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, const std::string& emsa, int nid) :
PK_Ops::Verification_with_EMSA(emsa), m_ossl_ec(::EC_KEY_new(), ::EC_KEY_free)
{
std::unique_ptr<::EC_GROUP, std::function<void (::EC_GROUP*)>> grp(::EC_GROUP_new_by_curve_name(nid),
::EC_GROUP_free);
if(!grp)
throw OpenSSL_Error("EC_GROUP_new_by_curve_name");
if(!::EC_KEY_set_group(m_ossl_ec.get(), grp.get()))
throw OpenSSL_Error("EC_KEY_set_group");
const secure_vector<uint8_t> enc = EC2OSP(ecdsa.public_point(), PointGFp::UNCOMPRESSED);
const uint8_t* enc_ptr = enc.data();
EC_KEY* key_ptr = m_ossl_ec.get();
if(!::o2i_ECPublicKey(&key_ptr, &enc_ptr, enc.size()))
throw OpenSSL_Error("o2i_ECPublicKey");
const EC_GROUP* group = ::EC_KEY_get0_group(m_ossl_ec.get());
m_order_bits = ::EC_GROUP_get_degree(group);
}
size_t max_input_bits() const override { return m_order_bits; }
bool with_recovery() const override { return false; }
bool verify(const uint8_t msg[], size_t msg_len,
const uint8_t sig_bytes[], size_t sig_len) override
{
const size_t order_bytes = (m_order_bits + 7) / 8;
if(sig_len != 2 * order_bytes)
return false;
std::unique_ptr<ECDSA_SIG, std::function<void (ECDSA_SIG*)>> sig(nullptr, ECDSA_SIG_free);
sig.reset(::ECDSA_SIG_new());
BIGNUM* r = BN_bin2bn(sig_bytes , sig_len / 2, nullptr);
BIGNUM* s = BN_bin2bn(sig_bytes + sig_len / 2, sig_len / 2, nullptr);
if(r == nullptr || s == nullptr)
throw OpenSSL_Error("BN_bin2bn sig s");
#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
sig->r = r;
sig->s = s;
#else
ECDSA_SIG_set0(sig.get(), r, s);
#endif
const int res = ECDSA_do_verify(msg, msg_len, sig.get(), m_ossl_ec.get());
if(res < 0)
throw OpenSSL_Error("ECDSA_do_verify");
return (res == 1);
}
private:
std::unique_ptr<EC_KEY, std::function<void (EC_KEY*)>> m_ossl_ec;
size_t m_order_bits = 0;
};
class OpenSSL_ECDSA_Signing_Operation : public PK_Ops::Signature_with_EMSA
{
public:
OpenSSL_ECDSA_Signing_Operation(const ECDSA_PrivateKey& ecdsa, const std::string& emsa) :
PK_Ops::Signature_with_EMSA(emsa),
m_ossl_ec(nullptr, ::EC_KEY_free)
{
const secure_vector<uint8_t> der = PKCS8_for_openssl(ecdsa);
const uint8_t* der_ptr = der.data();
m_ossl_ec.reset(d2i_ECPrivateKey(nullptr, &der_ptr, der.size()));
if(!m_ossl_ec)
throw OpenSSL_Error("d2i_ECPrivateKey");
const EC_GROUP* group = ::EC_KEY_get0_group(m_ossl_ec.get());
m_order_bits = ::EC_GROUP_get_degree(group);
}
secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len,
RandomNumberGenerator&) override
{
std::unique_ptr<ECDSA_SIG, std::function<void (ECDSA_SIG*)>> sig(nullptr, ECDSA_SIG_free);
sig.reset(::ECDSA_do_sign(msg, msg_len, m_ossl_ec.get()));
if(!sig)
throw OpenSSL_Error("ECDSA_do_sign");
const size_t order_bytes = (m_order_bits + 7) / 8;
#if OPENSSL_VERSION_NUMBER < 0x10100000L || defined(LIBRESSL_VERSION_NUMBER)
const BIGNUM* r = sig->r;
const BIGNUM* s = sig->s;
#else
const BIGNUM* r;
const BIGNUM* s;
ECDSA_SIG_get0(sig.get(), &r, &s);
#endif
const size_t r_bytes = BN_num_bytes(r);
const size_t s_bytes = BN_num_bytes(s);
secure_vector<uint8_t> sigval(2*order_bytes);
BN_bn2bin(r, &sigval[order_bytes - r_bytes]);
BN_bn2bin(s, &sigval[2*order_bytes - s_bytes]);
return sigval;
}
size_t max_input_bits() const override { return m_order_bits; }
private:
std::unique_ptr<EC_KEY, std::function<void (EC_KEY*)>> m_ossl_ec;
size_t m_order_bits = 0;
};
}
std::unique_ptr<PK_Ops::Verification>
make_openssl_ecdsa_ver_op(const ECDSA_PublicKey& key, const std::string& params)
{
const int nid = OpenSSL_EC_nid_for(key.domain());
if(nid < 0)
{
throw Lookup_Error("OpenSSL ECDSA does not support this curve");
}
return std::unique_ptr<PK_Ops::Verification>(new OpenSSL_ECDSA_Verification_Operation(key, params, nid));
}
std::unique_ptr<PK_Ops::Signature>
make_openssl_ecdsa_sig_op(const ECDSA_PrivateKey& key, const std::string& params)
{
const int nid = OpenSSL_EC_nid_for(key.domain());
if(nid < 0)
{
throw Lookup_Error("OpenSSL ECDSA does not support this curve");
}
return std::unique_ptr<PK_Ops::Signature>(new OpenSSL_ECDSA_Signing_Operation(key, params));
}
#endif
#if defined(BOTAN_HAS_ECDH) && !defined(OPENSSL_NO_ECDH)
namespace {
class OpenSSL_ECDH_KA_Operation : public PK_Ops::Key_Agreement_with_KDF
{
public:
OpenSSL_ECDH_KA_Operation(const ECDH_PrivateKey& ecdh, const std::string& kdf) :
PK_Ops::Key_Agreement_with_KDF(kdf), m_ossl_ec(::EC_KEY_new(), ::EC_KEY_free)
{
const secure_vector<uint8_t> der = PKCS8_for_openssl(ecdh);
const uint8_t* der_ptr = der.data();
m_ossl_ec.reset(d2i_ECPrivateKey(nullptr, &der_ptr, der.size()));
if(!m_ossl_ec)
throw OpenSSL_Error("d2i_ECPrivateKey");
}
secure_vector<uint8_t> raw_agree(const uint8_t w[], size_t w_len) override
{
const EC_GROUP* group = ::EC_KEY_get0_group(m_ossl_ec.get());
const size_t out_len = (::EC_GROUP_get_degree(group) + 7) / 8;
secure_vector<uint8_t> out(out_len);
EC_POINT* pub_key = ::EC_POINT_new(group);
if(!pub_key)
throw OpenSSL_Error("EC_POINT_new");
const int os2ecp_rc =
::EC_POINT_oct2point(group, pub_key, w, w_len, nullptr);
if(os2ecp_rc != 1)
throw OpenSSL_Error("EC_POINT_oct2point");
const int ecdh_rc = ::ECDH_compute_key(out.data(),
out.size(),
pub_key,
m_ossl_ec.get(),
/*KDF*/nullptr);
if(ecdh_rc <= 0)
throw OpenSSL_Error("ECDH_compute_key");
const size_t ecdh_sz = static_cast<size_t>(ecdh_rc);
if(ecdh_sz > out.size())
throw Internal_Error("OpenSSL ECDH returned more than requested");
out.resize(ecdh_sz);
return out;
}
private:
std::unique_ptr<EC_KEY, std::function<void (EC_KEY*)>> m_ossl_ec;
};
}
std::unique_ptr<PK_Ops::Key_Agreement>
make_openssl_ecdh_ka_op(const ECDH_PrivateKey& key, const std::string& params)
{
const int nid = OpenSSL_EC_nid_for(key.domain());
if(nid < 0)
{
throw Lookup_Error("OpenSSL ECDH does not support this curve");
}
return std::unique_ptr<PK_Ops::Key_Agreement>(new OpenSSL_ECDH_KA_Operation(key, params));
}
#endif
}
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