int GCMContext::authDecrypt(State & state, mbedtls_gcm_context * context){
Stack * stack = state.stack;
if (stack->is<LUA_TSTRING>(1) && stack->is<LUA_TSTRING>(2) && stack->is<LUA_TSTRING>(3)){
std::string ivStr = stack->toLString(1);
std::string input = stack->toLString(2);
std::string tagStr = stack->toLString(3);
size_t ivLength = ivStr.length();
size_t length = input.length();
size_t tagLength = tagStr.length();
unsigned char * additionalData = nullptr;
size_t addLength = 0;
if ((tagLength >= 4) && (tagLength <= 16)){
if (stack->is<LUA_TSTRING>(4)){
std::string additional = stack->toLString(4);
addLength = additional.length();
additionalData = new unsigned char[addLength];
memcpy(additionalData, additional.c_str(), addLength);
}
unsigned char * output = new unsigned char[length + 8];
int result = mbedtls_gcm_auth_decrypt(context, length,
reinterpret_cast<const unsigned char*>(ivStr.c_str()), ivLength,
additionalData, addLength,
reinterpret_cast<const unsigned char *>(tagStr.c_str()), tagLength,
reinterpret_cast<const unsigned char *>(input.c_str()), output
);
if (additionalData){
delete[] additionalData;
}
if (result == 0){
stack->pushLString(std::string(reinterpret_cast<char*>(output), length));
delete[] output;
}
else{
delete[] output;
stack->push<int>(result);
}
return 1;
}
}
return 0;
}
/*
* Packet-oriented decryption for AEAD modes
*/
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
const unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
tag, tag_len, input, output );
if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
input, output, tag, tag_len );
if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CCM_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
/*
* Packet-oriented decryption for AEAD modes
*/
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
const unsigned char *iv, size_t iv_len,
const unsigned char *ad, size_t ad_len,
const unsigned char *input, size_t ilen,
unsigned char *output, size_t *olen,
const unsigned char *tag, size_t tag_len )
{
#if defined(MBEDTLS_GCM_C)
if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_gcm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
tag, tag_len, input, output );
if( ret == MBEDTLS_ERR_GCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_GCM_C */
#if defined(MBEDTLS_CCM_C)
if( MBEDTLS_MODE_CCM == ctx->cipher_info->mode )
{
int ret;
*olen = ilen;
ret = mbedtls_ccm_auth_decrypt( ctx->cipher_ctx, ilen,
iv, iv_len, ad, ad_len,
input, output, tag, tag_len );
if( ret == MBEDTLS_ERR_CCM_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CCM_C */
#if defined(MBEDTLS_CHACHAPOLY_C)
if ( MBEDTLS_CIPHER_CHACHA20_POLY1305 == ctx->cipher_info->type )
{
int ret;
/* ChachaPoly has fixed length nonce and MAC (tag) */
if ( ( iv_len != ctx->cipher_info->iv_size ) ||
( tag_len != 16U ) )
{
return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
}
*olen = ilen;
ret = mbedtls_chachapoly_auth_decrypt( ctx->cipher_ctx, ilen,
iv, ad, ad_len, tag, input, output );
if( ret == MBEDTLS_ERR_CHACHAPOLY_AUTH_FAILED )
ret = MBEDTLS_ERR_CIPHER_AUTH_FAILED;
return( ret );
}
#endif /* MBEDTLS_CHACHAPOLY_C */
return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
}
