/*
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* verifier.cpp
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*
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* Created on: Nov 16, 2019
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* Author: devel
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*/
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#include "../os.h"
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#include <stdio.h>
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#include <sstream>
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#include <iostream>
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#include <fstream>
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#include <vector>
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#include <bcrypt.h>
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#include <wincrypt.h>
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#include <iphlpapi.h>
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#include <windows.h>
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#pragma comment(lib, "bcrypt.lib")
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#include <public_key.h>
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#include "../../base/logger.h"
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#include "../../base/base64.h"
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#include "../signature_verifier.h"
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#define RSA_KEY_BITLEN 1024
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namespace license {
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using namespace std;
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#define NT_SUCCESS(Status) (((NTSTATUS)(Status)) >= 0)
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static const void formatError(DWORD status, const char* description) {
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char msgBuffer[256];
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FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, status, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), &msgBuffer[0],
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sizeof(msgBuffer) - 1, nullptr);
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LOG_DEBUG("error %s : %s %h", description, msgBuffer, status);
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}
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#pragma pack(push, 1)
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typedef struct {
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BCRYPT_RSAKEY_BLOB rsakey;
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BYTE pkExp[3];
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BYTE modulus[RSA_KEY_BITLEN / 8];
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} PUBKEY_BLOB, *P_PUBKEY_BLOB;
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#pragma pack(pop)
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static BCRYPT_ALG_HANDLE openSignatureProvider() {
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DWORD status;
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BCRYPT_ALG_HANDLE hSignAlg = nullptr;
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return hSignAlg;
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}
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static BCRYPT_ALG_HANDLE openHashProvider() {
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DWORD status;
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BCRYPT_ALG_HANDLE hHashAlg = nullptr;
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if (!NT_SUCCESS(status = BCryptOpenAlgorithmProvider(&hHashAlg, BCRYPT_SHA256_ALGORITHM, NULL, 0))) {
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throw logic_error("Error opening hash provider");
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}
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return hHashAlg;
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}
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static DWORD hashData(BCRYPT_HASH_HANDLE& hHash, const string& data, PBYTE pbHash, DWORD hashDataLenght) {
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DWORD status;
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bool success = false;
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if (NT_SUCCESS(status = BCryptHashData(hHash, (BYTE*)data.c_str(), (ULONG)data.length(), 0))) {
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status = BCryptFinishHash(hHash, pbHash, hashDataLenght, 0);
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}
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return status;
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}
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static size_t read_length(uint8_t*& ptr) {
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uint8_t len = *ptr++;
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size_t result = 0;
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cout << (len & 0x80) << endl;
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if ((len & 0x80) > 0) {
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size_t blen = len & 0x7F;
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for (int i = 0; i < blen; i++) {
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result += (*(ptr++) << (i * 8));
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}
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} else {
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result = len;
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}
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return result;
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}
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static FUNCTION_RETURN read_sequence(uint8_t*& ptr) {
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uint8_t tag = *ptr++;
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if (tag != 0x30) {
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return FUNC_RET_ERROR;
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}
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read_length(ptr);
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return FUNC_RET_OK;
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}
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static FUNCTION_RETURN read_integer(uint8_t*& ptr, BYTE* location, const size_t expected_length) {
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uint8_t tag = *ptr++;
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if (tag != 0x02) {
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return FUNC_RET_ERROR;
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}
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size_t length = read_length(ptr);
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// skip the padding byte
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if (*ptr == 0) {
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length--;
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ptr++;
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}
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if (expected_length < length) {
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return FUNC_RET_ERROR;
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}
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for (int i = 0; i < length; i++) {
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location[i] = *(ptr++);
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}
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return FUNC_RET_OK;
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}
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static FUNCTION_RETURN readPublicKey(const BCRYPT_ALG_HANDLE sig_alg, BCRYPT_KEY_HANDLE* hKey) {
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FUNCTION_RETURN result = FUNC_RET_ERROR;
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DWORD status;
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PUBKEY_BLOB pubk;
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pubk.rsakey.Magic = BCRYPT_RSAPUBLIC_MAGIC;
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pubk.rsakey.BitLength = RSA_KEY_BITLEN;
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pubk.rsakey.cbPublicExp = 3;
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pubk.rsakey.cbModulus = RSA_KEY_BITLEN / 8;
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pubk.rsakey.cbPrime1 = 0;
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pubk.rsakey.cbPrime2 = 0;
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uint8_t pubKey[] = PUBLIC_KEY;
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uint8_t* pub_key_idx = &pubKey[0];
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read_sequence(pub_key_idx);
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read_integer(pub_key_idx, (BYTE*)&pubk.modulus, sizeof(pubk.modulus));
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read_integer(pub_key_idx, (BYTE*)&pubk.pkExp, sizeof(pubk.pkExp));
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if (NT_SUCCESS(status = BCryptImportKeyPair(sig_alg, nullptr, BCRYPT_RSAPUBLIC_BLOB, hKey, (PUCHAR)&pubk,
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sizeof(pubk), 0))) {
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result = FUNC_RET_OK;
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} else {
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#ifdef _DEBUG
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formatError(status, "error importing public key");
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#endif
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}
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return result;
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}
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static FUNCTION_RETURN verifyHash(const PBYTE pbHash, const DWORD hashDataLenght, const string& signatureBuffer) {
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BCRYPT_KEY_HANDLE phKey = nullptr;
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DWORD status;
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FUNCTION_RETURN result = FUNC_RET_ERROR;
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PBYTE pbSignature = nullptr;
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DWORD dwSigLen;
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BYTE* sigBlob = nullptr;
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BCRYPT_ALG_HANDLE hSignAlg = nullptr;
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// FIXME!!
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sigBlob = unbase64(signatureBuffer.c_str(), (int)signatureBuffer.size(), (int*)&dwSigLen);
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if (NT_SUCCESS(status = BCryptOpenAlgorithmProvider(&hSignAlg, BCRYPT_RSA_ALGORITHM, NULL, 0))) {
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if ((result = readPublicKey(hSignAlg, &phKey)) == FUNC_RET_OK) {
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BCRYPT_PKCS1_PADDING_INFO paddingInfo;
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ZeroMemory(&paddingInfo, sizeof(paddingInfo));
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paddingInfo.pszAlgId = BCRYPT_SHA256_ALGORITHM;
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if (NT_SUCCESS(status = BCryptVerifySignature(phKey, &paddingInfo, pbHash, hashDataLenght, sigBlob,
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dwSigLen, BCRYPT_PAD_PKCS1))) {
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result = FUNC_RET_OK;
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} else {
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result = FUNC_RET_ERROR;
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#ifdef _DEBUG
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formatError(status, "error verifying signature");
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#endif
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}
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} else {
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LOG_DEBUG("Error reading public key");
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}
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} else {
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result = FUNC_RET_NOT_AVAIL;
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#ifdef _DEBUG
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formatError(status, "error opening RSA provider");
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#endif
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}
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if (phKey != nullptr) {
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BCryptDestroyKey(phKey);
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}
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if (hSignAlg != nullptr) {
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BCryptCloseAlgorithmProvider(hSignAlg, 0);
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}
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if (sigBlob) {
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free(sigBlob);
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}
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return result;
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}
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FUNCTION_RETURN verify_signature(const std::string& stringToVerify, const std::string& signatureB64) {
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BCRYPT_HASH_HANDLE hHash = nullptr;
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PBYTE pbHashObject = nullptr, pbHashData = nullptr;
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FUNCTION_RETURN result = FUNC_RET_ERROR;
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const HANDLE hProcessHeap = GetProcessHeap();
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// BCRYPT_ALG_HANDLE sig_alg = openSignatureProvider();
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BCRYPT_ALG_HANDLE hash_alg = openHashProvider();
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DWORD status;
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// calculate the size of the buffer to hold the hash object
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DWORD cbData = 0, cbHashObject = 0;
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// and the size to keep the hashed data
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DWORD cbHashDataLenght = 0;
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if (NT_SUCCESS(status = BCryptGetProperty(hash_alg, BCRYPT_OBJECT_LENGTH, (PBYTE)&cbHashObject, sizeof(DWORD),
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&cbData, 0)) &&
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NT_SUCCESS(status = BCryptGetProperty(hash_alg, BCRYPT_HASH_LENGTH, (PBYTE)&cbHashDataLenght, sizeof(DWORD),
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&cbData, 0))) {
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// allocate the hash object on the heap
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pbHashObject = (PBYTE)HeapAlloc(hProcessHeap, 0, cbHashObject);
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pbHashData = (PBYTE)HeapAlloc(hProcessHeap, 0, cbHashDataLenght);
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if (NULL != pbHashObject && nullptr != pbHashData) {
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if (NT_SUCCESS(status = BCryptCreateHash(hash_alg, &hHash, pbHashObject, cbHashObject, NULL, 0, 0))) {
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if (NT_SUCCESS(status = hashData(hHash, stringToVerify, pbHashData, cbHashDataLenght))) {
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result = verifyHash(pbHashData, cbHashDataLenght, signatureB64);
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} else {
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result = FUNC_RET_NOT_AVAIL;
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#ifdef _DEBUG
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formatError(status, "error hashing data");
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#endif
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}
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} else {
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result = FUNC_RET_NOT_AVAIL;
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#ifdef _DEBUG
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formatError(status, "error creating hash");
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#endif
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}
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} else {
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result = FUNC_RET_BUFFER_TOO_SMALL;
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LOG_DEBUG("Error allocating memory");
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}
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} else {
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result = FUNC_RET_NOT_AVAIL;
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#ifdef _DEBUG
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formatError(status, "**** Error returned by BCryptGetProperty");
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#endif
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}
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if (hHash) {
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BCryptDestroyHash(hHash);
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}
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if (pbHashObject) {
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HeapFree(hProcessHeap, 0, pbHashObject);
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}
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if (pbHashData) {
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HeapFree(hProcessHeap, 0, pbHashData);
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}
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if (hash_alg != nullptr) {
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BCryptCloseAlgorithmProvider(hash_alg, 0);
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}
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return result;
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}
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} /* namespace license */
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