How to recover the effective rights of a registry key? c++ - c++

Question

I would like to retrieve the effective rights of a given registry key as a parameter. I test with an existing registry key under Windows. To do that I use the methods CreateFile, GetSecurityInfo and GetEffectiveRightsFromAclA.
I wanted to know if this is the correct method, because I have an error for the CreateFile method that returns INVALID_HANDLE_VALUE. Moreover for the method GetEffectiveRightsFromAclA, I do not understand which parameter I must put in TRUSTEE_A?
LPCWSTR lpwRegistryKey = L"HKEY_CLASSES_ROOT\\.acc\\OpenWithProgids\\WMP11.AssocFile.ADTS";
HANDLE handleKey;
handleKey = CreateFile(lpwRegistryKey, GENERIC_READ, FILE_SHARED_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
if(handleKey == INVALID_HANDLE_VALUE)
{
//qDebug()<<"error";
}
//Here is an user SID
PSID pUserSid;
QString sSid("S-4-5-12");
BOOL resultSidConvert = ConvertStringSidToSidA(sSid.toStdString().c_str(), &pUserSid);
//Here success
if(resultSidConvert != 0)
{
PACL pDacl;
PSECURITY_DESCRIPTOR pSecurityDescriptor;
DWORD dwResultSecurity = GetSecurityInfo(handleKey, SE_REGISTRY_KEY, DACL_SECURITY_INFORMATION, nullptr, &pUserSid, &pDacl, nullptr, &pSecurityDescritptor);
if(dwResultSecurity == ERROR_SUCCESS)
{
ACCESS_MASK pAccessMask;
TRUSTEE_A pTrustee; //How should I initialize pTrustee?
DWORD dwEffectiveRights = (GetEffectiveRightsFromAclA(pDacl, &pTrustee, &pAccessMask);
if(dwEffectiveRights == ERROR_SUCCESS)
{
if((pAccessMask & DELETE) == DELETE)
{
qDebug()<<"Delete";
}
if((pAccessMask & GENERIC_READ) == GENERIC_READ)
{
qDebug()<<"READ";
}
//etc ..........
}
}
}

Answer 1

A registry key is not a file!
Don't use CreateFile. Use RegOpenKeyEx instead.
First, you must run the application as admin.
Then, you can open the key successfully. After that, take a look at RegGetKeySecurity function.