NtOpenSection访问拒绝是什么原因

attributes.Length                    = sizeof(OBJECT_ATTRIBUTES);
attributes.RootDirectory            = NULL;
attributes.ObjectName                = &physmemString;
attributes.Attributes                = 0;
attributes.SecurityDescriptor        = NULL;
attributes.SecurityQualityOfService    = NULL;
VOID SetPhyscialMemorySectionCanBeWrited(HANDLE hSection) 
{ 
    PACL pDacl                    = NULL; 
    PSECURITY_DESCRIPTOR pSD    = NULL; 
    PACL pNewDacl = NULL; 
    
    DWORD dwRes = GetSecurityInfo(hSection, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, NULL,     NULL, &pDacl, NULL, &pSD);    if(ERROR_SUCCESS != dwRes)
    {    if(pSD) 
        LocalFree(pSD); 
    if(pNewDacl) 
        LocalFree(pNewDacl); 
    }    EXPLICIT_ACCESS ea; 
    RtlZeroMemory(&ea, sizeof(EXPLICIT_ACCESS)); 
    ea.grfAccessPermissions = SECTION_MAP_WRITE; 
    ea.grfAccessMode = GRANT_ACCESS; 
    ea.grfInheritance= NO_INHERITANCE; 
    ea.Trustee.TrusteeForm = TRUSTEE_IS_NAME; 
    ea.Trustee.TrusteeType = TRUSTEE_IS_USER; 
    ea.Trustee.ptstrName = "CURRENT_USER";     dwRes = SetEntriesInAcl(1,&ea,pDacl,&pNewDacl);
    
    if(ERROR_SUCCESS != dwRes)
    {    if(pSD) 
        LocalFree(pSD); 
    if(pNewDacl) 
        LocalFree(pNewDacl); 
    }
    dwRes = SetSecurityInfo(hSection,SE_KERNEL_OBJECT,DACL_SECURITY_INFORMATION,NULL,NULL,pNewDacl,NULL);
    
    if(ERROR_SUCCESS != dwRes)
    {    if(pSD) 
        LocalFree(pSD); 
    if(pNewDacl) 
        LocalFree(pNewDacl); 
    }}     status = NtOpenSection(&g_hMPM, SECTION_MAP_READ|SECTION_MAP_WRITE, &attributes);     if(status == STATUS_ACCESS_DENIED)
    { 
        status = NtOpenSection(&g_hMPM, READ_CONTROL|WRITE_DAC, &attributes); 
        SetPhyscialMemorySectionCanBeWrited(g_hMPM); 
        CloseHandle(g_hMPM);
DWORD test=GetLastError();
        status = NtOpenSection(&g_hMPM, SECTION_MAP_READ|SECTION_MAP_WRITE, &attributes); 
        //这里返回的值始终是拒绝访问，这是什么原因    }    if(!NT_SUCCESS(status)) 
        return NULL;    g_pMapPhysicalMemory = MapViewOfFile(g_hMPM, FILE_MAP_READ|FILE_MAP_WRITE, 0, PhyDirectory, 0x1000);    if( g_pMapPhysicalMemory == NULL )
        return NULL;