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/*
* OpenSSL RSA interface
* (C) 2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/openssl.h>
#if defined(BOTAN_HAS_RSA)
#include <botan/rsa.h>
#include <botan/internal/pk_utils.h>
#include <functional>
#include <memory>
#include <openssl/rsa.h>
#include <openssl/x509.h>
#include <openssl/err.h>
namespace Botan {
namespace {
std::pair<int, size_t> get_openssl_enc_pad(const std::string& eme)
{
ERR_load_crypto_strings();
if(eme == "Raw")
return std::make_pair(RSA_NO_PADDING, 0);
else if(eme == "EME-PKCS1-v1_5")
return std::make_pair(RSA_PKCS1_PADDING, 11);
else if(eme == "OAEP(SHA-1)")
return std::make_pair(RSA_PKCS1_OAEP_PADDING, 41);
else
throw Lookup_Error("OpenSSL RSA does not support EME " + eme);
}
class OpenSSL_RSA_Encryption_Operation : public PK_Ops::Encryption
{
public:
typedef RSA_PublicKey Key_Type;
static OpenSSL_RSA_Encryption_Operation* make(const Spec& spec)
{
try
{
if(auto* key = dynamic_cast<const RSA_PublicKey*>(&spec.key()))
{
auto pad_info = get_openssl_enc_pad(spec.padding());
return new OpenSSL_RSA_Encryption_Operation(*key, pad_info.first, pad_info.second);
}
}
catch(...) {}
return nullptr;
}
OpenSSL_RSA_Encryption_Operation(const RSA_PublicKey& rsa, int pad, size_t pad_overhead) :
m_openssl_rsa(nullptr, ::RSA_free), m_padding(pad)
{
const std::vector<byte> der = rsa.x509_subject_public_key();
const byte* der_ptr = der.data();
m_openssl_rsa.reset(::d2i_RSAPublicKey(nullptr, &der_ptr, der.size()));
if(!m_openssl_rsa)
throw OpenSSL_Error("d2i_RSAPublicKey");
m_bits = 8 * (n_size() - pad_overhead);
}
size_t max_input_bits() const override { return m_bits - 1; };
secure_vector<byte> encrypt(const byte msg[], size_t msg_len,
RandomNumberGenerator&) override
{
const size_t mod_sz = n_size();
if(msg_len > mod_sz)
throw Invalid_Argument("Input too large for RSA key");
secure_vector<byte> outbuf(mod_sz);
secure_vector<byte> inbuf;
if(m_padding == RSA_NO_PADDING)
{
inbuf.resize(mod_sz);
copy_mem(&inbuf[mod_sz - msg_len], msg, msg_len);
}
else
{
inbuf.assign(msg, msg + msg_len);
}
int rc = ::RSA_public_encrypt(inbuf.size(), inbuf.data(), outbuf.data(),
m_openssl_rsa.get(), m_padding);
if(rc < 0)
throw OpenSSL_Error("RSA_public_encrypt");
return outbuf;
}
private:
size_t n_size() const { return ::RSA_size(m_openssl_rsa.get()); }
std::unique_ptr<RSA, std::function<void (RSA*)>> m_openssl_rsa;
size_t m_bits = 0;
int m_padding = 0;
};
class OpenSSL_RSA_Decryption_Operation : public PK_Ops::Decryption
{
public:
typedef RSA_PrivateKey Key_Type;
static OpenSSL_RSA_Decryption_Operation* make(const Spec& spec)
{
try
{
if(auto* key = dynamic_cast<const RSA_PrivateKey*>(&spec.key()))
{
auto pad_info = get_openssl_enc_pad(spec.padding());
return new OpenSSL_RSA_Decryption_Operation(*key, pad_info.first);
}
}
catch(...) {}
return nullptr;
}
OpenSSL_RSA_Decryption_Operation(const RSA_PrivateKey& rsa, int pad) :
m_openssl_rsa(nullptr, ::RSA_free), m_padding(pad)
{
const secure_vector<byte> der = rsa.pkcs8_private_key();
const byte* der_ptr = der.data();
m_openssl_rsa.reset(d2i_RSAPrivateKey(nullptr, &der_ptr, der.size()));
if(!m_openssl_rsa)
throw OpenSSL_Error("d2i_RSAPrivateKey");
m_bits = 8 * ::RSA_size(m_openssl_rsa.get());
}
size_t max_input_bits() const override { return m_bits - 1; }
secure_vector<byte> decrypt(const byte msg[], size_t msg_len) override
{
secure_vector<byte> buf(::RSA_size(m_openssl_rsa.get()));
int rc = ::RSA_private_decrypt(msg_len, msg, buf.data(), m_openssl_rsa.get(), m_padding);
if(rc < 0 || static_cast<size_t>(rc) > buf.size())
throw OpenSSL_Error("RSA_private_decrypt");
buf.resize(rc);
if(m_padding == RSA_NO_PADDING)
{
size_t leading_0s = 0;
while(leading_0s < buf.size() && buf[leading_0s] == 0)
leading_0s++;
if(leading_0s)
return secure_vector<byte>(&buf[leading_0s], &buf[buf.size()]);
}
return buf;
}
private:
std::unique_ptr<RSA, std::function<void (RSA*)>> m_openssl_rsa;
size_t m_bits = 0;
int m_padding = 0;
};
BOTAN_REGISTER_TYPE(PK_Ops::Encryption, OpenSSL_RSA_Encryption_Operation, "RSA",
OpenSSL_RSA_Encryption_Operation::make, "openssl", BOTAN_OPENSSL_RSA_PRIO);
BOTAN_REGISTER_TYPE(PK_Ops::Decryption, OpenSSL_RSA_Decryption_Operation, "RSA",
OpenSSL_RSA_Decryption_Operation::make, "openssl", BOTAN_OPENSSL_RSA_PRIO);
}
}
#endif // BOTAN_HAS_RSA
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