cpp-jwt/include/jwt/impl/algorithm.ipp
2017-12-27 15:39:38 +05:30

321 lines
7.9 KiB
C++

/*
Copyright (c) 2017 Arun Muralidharan
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
*/
#ifndef CPP_JWT_ALGORITHM_IPP
#define CPP_JWT_ALGORITHM_IPP
namespace jwt {
template <typename Hasher>
verify_result_t HMACSign<Hasher>::verify(
const string_view key,
const string_view head,
const string_view jwt_sign)
{
std::error_code ec{};
BIO_uptr b64{BIO_new(BIO_f_base64()), bio_deletor};
if (!b64) {
throw MemoryAllocationException("BIO_new failed");
}
BIO* bmem = BIO_new(BIO_s_mem());
if (!bmem) {
throw MemoryAllocationException("BIO_new failed");
}
BIO_push(b64.get(), bmem);
BIO_set_flags(b64.get(), BIO_FLAGS_BASE64_NO_NL);
unsigned char enc_buf[EVP_MAX_MD_SIZE];
uint32_t enc_buf_len = 0;
unsigned char* res = HMAC(Hasher{}(),
key.data(),
key.length(),
reinterpret_cast<const unsigned char*>(head.data()),
head.length(),
enc_buf,
&enc_buf_len);
if (!res) {
ec = AlgorithmErrc::VerificationErr;
return {false, ec};
}
BIO_write(b64.get(), enc_buf, enc_buf_len);
(void)BIO_flush(b64.get());
int len = BIO_pending(bmem);
if (len < 0) {
ec = AlgorithmErrc::VerificationErr;
return {false, ec};
}
std::string cbuf;
cbuf.resize(len + 1);
len = BIO_read(bmem, &cbuf[0], len);
cbuf.resize(len);
//Make the base64 string url safe
auto new_len = jwt::base64_uri_encode(&cbuf[0], cbuf.length());
cbuf.resize(new_len);
bool ret = (string_view{cbuf} == jwt_sign);
return { ret, ec };
}
template <typename Hasher>
verify_result_t PEMSign<Hasher>::verify(
const string_view key,
const string_view head,
const string_view jwt_sign)
{
std::error_code ec{};
std::string dec_sig = base64_uri_decode(jwt_sign.data(), jwt_sign.length());
BIO_uptr bufkey{
BIO_new_mem_buf((void*)key.data(), key.length()),
bio_deletor};
if (!bufkey) {
throw MemoryAllocationException("BIO_new_mem_buf failed");
}
EC_PKEY_uptr pkey{
PEM_read_bio_PUBKEY(bufkey.get(), nullptr, nullptr, nullptr),
ev_pkey_deletor};
if (!pkey) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
int pkey_type = EVP_PKEY_id(pkey.get());
if (pkey_type != Hasher::type) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
//Convert EC signature back to ASN1
if (Hasher::type == EVP_PKEY_EC) {
EC_SIG_uptr ec_sig{ECDSA_SIG_new(), ec_sig_deletor};
if (!ec_sig) {
throw MemoryAllocationException("ECDSA_SIG_new failed");
}
//Get the actual ec_key
EC_KEY_uptr ec_key{EVP_PKEY_get1_EC_KEY(pkey.get()), ec_key_deletor};
if (!ec_key) {
throw MemoryAllocationException("EVP_PKEY_get1_EC_KEY failed");
}
unsigned int degree = EC_GROUP_get_degree(
EC_KEY_get0_group(ec_key.get()));
unsigned int bn_len = (degree + 7) / 8;
if ((bn_len * 2) != dec_sig.length()) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
BIGNUM* ec_sig_r = BN_bin2bn((unsigned char*)dec_sig.data(), bn_len, nullptr);
BIGNUM* ec_sig_s = BN_bin2bn((unsigned char*)dec_sig.data() + bn_len, bn_len, nullptr);
if (!ec_sig_r || !ec_sig_s) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
ECDSA_SIG_set0(ec_sig.get(), ec_sig_r, ec_sig_s);
size_t nlen = i2d_ECDSA_SIG(ec_sig.get(), nullptr);
dec_sig.resize(nlen);
auto data = reinterpret_cast<unsigned char*>(&dec_sig[0]);
nlen = i2d_ECDSA_SIG(ec_sig.get(), &data);
if (nlen == 0) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
}
EVP_MDCTX_uptr mdctx_ptr{EVP_MD_CTX_create(), evp_md_ctx_deletor};
if (!mdctx_ptr) {
throw MemoryAllocationException("EVP_MD_CTX_create failed");
}
if (EVP_DigestVerifyInit(
mdctx_ptr.get(), nullptr, Hasher{}(), nullptr, pkey.get()) != 1) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
if (EVP_DigestVerifyUpdate(mdctx_ptr.get(), head.data(), head.length()) != 1) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
if (EVP_DigestVerifyFinal(
mdctx_ptr.get(), (unsigned char*)&dec_sig[0], dec_sig.length()) != 1) {
ec = AlgorithmErrc::VerificationErr;
return { false, ec };
}
return { true, ec };
}
template <typename Hasher>
EVP_PKEY* PEMSign<Hasher>::load_key(
const string_view key,
std::error_code& ec)
{
ec.clear();
BIO_uptr bio_ptr{
BIO_new_mem_buf((void*)key.data(), key.length()),
bio_deletor};
if (!bio_ptr) {
throw MemoryAllocationException("BIO_new_mem_buf failed");
}
EVP_PKEY* pkey = PEM_read_bio_PrivateKey(
bio_ptr.get(), nullptr, nullptr, nullptr);
if (!pkey) {
ec = AlgorithmErrc::SigningErr;
return nullptr;
}
auto pkey_type = EVP_PKEY_id(pkey);
if (pkey_type != Hasher::type) {
ec = AlgorithmErrc::SigningErr;
return nullptr;
}
return pkey;
}
template <typename Hasher>
std::string PEMSign<Hasher>::evp_digest(
EVP_PKEY* pkey,
const string_view data,
std::error_code& ec)
{
ec.clear();
EVP_MDCTX_uptr mdctx_ptr{EVP_MD_CTX_create(), evp_md_ctx_deletor};
if (!mdctx_ptr) {
throw MemoryAllocationException("EVP_MD_CTX_create failed");
}
//Initialiaze the digest algorithm
if (EVP_DigestSignInit(
mdctx_ptr.get(), nullptr, Hasher{}(), nullptr, pkey) != 1) {
ec = AlgorithmErrc::SigningErr;
return {};
}
//Update the digest with the input data
if (EVP_DigestSignUpdate(mdctx_ptr.get(), data.data(), data.length()) != 1) {
ec = AlgorithmErrc::SigningErr;
return {};
}
unsigned long len = 0;
if (EVP_DigestSignFinal(mdctx_ptr.get(), nullptr, &len) != 1) {
ec = AlgorithmErrc::SigningErr;
return {};
}
std::string sign;
sign.resize(len);
//Get the signature
if (EVP_DigestSignFinal(mdctx_ptr.get(), (unsigned char*)&sign[0], &len) != 1) {
ec = AlgorithmErrc::SigningErr;
return {};
}
return sign;
}
template <typename Hasher>
std::string PEMSign<Hasher>::public_key_ser(
EVP_PKEY* pkey,
string_view sign,
std::error_code& ec)
{
// Get the EC_KEY representing a public key and
// (optionaly) an associated private key
std::string new_sign;
ec.clear();
EC_KEY_uptr ec_key{EVP_PKEY_get1_EC_KEY(pkey), ec_key_deletor};
if (!ec_key) {
ec = AlgorithmErrc::SigningErr;
return {};
}
uint32_t degree = EC_GROUP_get_degree(EC_KEY_get0_group(ec_key.get()));
ec_key.reset(nullptr);
auto char_ptr = &sign[0];
EC_SIG_uptr ec_sig{d2i_ECDSA_SIG(nullptr,
(const unsigned char**)&char_ptr,
sign.length()),
ec_sig_deletor};
if (!ec_sig) {
ec = AlgorithmErrc::SigningErr;
return {};
}
const BIGNUM* ec_sig_r = nullptr;
const BIGNUM* ec_sig_s = nullptr;
ECDSA_SIG_get0(ec_sig.get(), &ec_sig_r, &ec_sig_s);
auto r_len = BN_num_bytes(ec_sig_r);
auto s_len = BN_num_bytes(ec_sig_s);
auto bn_len = (degree + 7) / 8;
if ((r_len > bn_len) || (s_len > bn_len)) {
ec = AlgorithmErrc::SigningErr;
return {};
}
auto buf_len = 2 * bn_len;
new_sign.resize(buf_len);
BN_bn2bin(ec_sig_r, (unsigned char*)&new_sign[0] + bn_len - r_len);
BN_bn2bin(ec_sig_s, (unsigned char*)&new_sign[0] + buf_len - s_len);
return new_sign;
}
} // END namespace jwt
#endif