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In the code below, pGPOList (the GPO list) is always NULL even when the GetAppliedGPOList returns success. I have tried multiple group policy extension GUIDs, but no luck. What am I doing wrong? This also happens when I try GetAppliedGPOList with user policies, although the code is slightly different.
static DWORD DisplayAppliedMachinePolicies()
{
PGROUP_POLICY_OBJECT pGPOList = NULL;
LPGROUPPOLICYOBJECT pGPO = NULL;
UUID guid;
DWORD dwError = 0;
//{17D89FEC-5C44-4972-B12D-241CAEF74509}
//{3A0DBA37-F8B2-4356-83DE-3E90BD5C261F}
//{E47248BA-94CC-49c4-BBB5-9EB7F05183D0}
if (string_to_guid(L"E47248BA-94CC-49c4-BBB5-9EB7F05183D0", &guid) != 0)
{
return ERROR_BAD_FORMAT;
}
dwError = GetAppliedGPOList(GPO_LIST_FLAG_MACHINE, NULL, NULL, &guid, &pGPOList);
if (dwError == ERROR_SUCCESS)
{
PGROUP_POLICY_OBJECT pGPO = (PGROUP_POLICY_OBJECT)pGPOList;
while (pGPO != NULL)
{
//Display properties of each GPO
DisplayPolicyInfo((PGROUP_POLICY_OBJECT)&pGPOList);
pGPO = pGPO->pNext;
}
FreeGPOList((PGROUP_POLICY_OBJECT)pGPOList);
}
return dwError;
}
Did you also obtain ERROR_SUCCESS with any random GUID?
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(179.20000000000002, 34%, 27%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EXY%3C/text%3E%3C/svg%3E)
The GetAppliedGPOList is looked under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy\History\{GuidExtension} key. Refer to https://stackoverflow.com/questions/46305094/getappliedgpolist-and-pguidextension-value.
So I always get ERROR_SUCCESS, but the GUIDS I have tried under the reg key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy\History{GuidExtension} have not yielded any non-null pointers for pGPOList yet. Perhaps I have tried the wrong ones - I will loop through all of them to test.
Thanks for the input!
Below is what I have so far - the DisplayAppliedMachinePolicies and DisplayAppliedUserPolicies functions work provided you supply the FQDN and user id or pin. However, I have not been able to get the DisplayMachinePolicies or DisplayUserPolicies functions to work. For the DisplayMachinePolicies function, I get the "RPC Server unavailable" error after the GetGPOList API is executed. The GetGPOList API states __"__Typically, to retrieve a list of GPOs for a computer, you can call GetGPOList with the computer name and domain controller name as demonstrated, but I keep getting the "RPC Server unavailbale" error. Hopefully someone else can enlighten me on what I am doing wrong.
#include "GPInfo.h"
int main()
{
ExtensionList m_xlist;
EnumGuidExtensions(TRUE, m_xlist);
DisplayMachinePolicies(m_xlist);
//DisplayAppliedMachinePolicies(m_xlist);
//DisplayAppliedUserPolicies( m_xlist, L"MyFQDN\\MyUserPin");
//DisplayUserPolicies(m_xlist, L"MyFQDN\\MyUserPin);
}
static DWORD EnumGuidExtensions(BOOL bAll, ExtensionList& el)
{
LONG nResult;
DWORD nKeyIdx = 0;
WCHAR wsRegBuffer[MAX_PATH + 1] = L"";
HKEY hKey = NULL;
int i = 0;
wstring wRegPath;
if (bAll == TRUE)
{
wRegPath.assign(L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon\\GPExtensions");
}
else
{
wRegPath.assign(L"SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Group Policy\\History");
}
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, wRegPath.c_str(), 0, KEY_READ | KEY_WOW64_64KEY, &hKey) == ERROR_SUCCESS)
{
while (TRUE)
{
nResult = RegEnumKey(hKey, nKeyIdx, wsRegBuffer, ARRAYSIZE(wsRegBuffer));
if (nResult == ERROR_NO_MORE_ITEMS)
{
break;
}
else
{
// Add extension to the list...
el.push_back(wsRegBuffer);
i++;
}
++nKeyIdx;
}
RegCloseKey(hKey);
}
else
{
return ERROR_REGISTRY_IO_FAILED;
}
return ERROR_SUCCESS;
}
/// <summary>
/// DisplayError
/// </summary>
/// <param name="dwError"></param>
static void DisplayError(DWORD dwError)
{
LPVOID lpMsgBuf;
FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,dwError, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPWSTR)&lpMsgBuf, 0, NULL);
wprintf(L"Error: %s\n", (LPCWSTR)lpMsgBuf);
if (lpMsgBuf)
{
LocalFree(lpMsgBuf);
}
}
/// <summary>
/// DisplayMachinePolicy
///
/// Note: The GetGPOList function retrieves the list of GPOs for the specified user or computer.
///
/// LPCSTR lpFQDN: A pointer to the user or computer name, in the fully qualified distinguished name format
/// (for example, "CN=user, OU=users, DC=contoso, DC=com").
/// LPCSTR hpHost: A DNS domain name (preferred) or domain controller name. Domain controller name can be retrieved using
/// the DsGetDcName function, specifying DS_DIRECTORY_SERVICE_REQUIRED in the flags parameter.
/// If the hToken parameter is not NULL, this parameter must be NULL.
///
/// LPCSTR lpComputerName: if this is NULL, the local computer name is used
/// </summary>
/// <returns></returns>
static DWORD DisplayMachinePolicies(ExtensionList& xl)
{
HRESULT hr;
PGROUP_POLICY_OBJECT pGPOList;
LPGROUPPOLICYOBJECT pGPO = NULL;
EXTENDED_NAME_FORMAT enf = NameFullyQualifiedDN;
LPCWSTR lpDcName = NULL;
UUID guid;
PDOMAIN_CONTROLLER_INFO dci;
WCHAR buff[MAX_PATH] = { 0 };
DWORD dwSz = sizeof(WCHAR) * sizeof(buff);
DWORD dwError;
list<wstring>::iterator it;
if (!GetComputerObjectName(enf, (LPWSTR)buff, &dwSz))
{
dwError = GetLastError();
wprintf(L"GetComputerObjectName failed, reason: %d\n", dwError);
return dwError;
}
NET_API_STATUS nStatus = DsGetDcName(NULL, NULL, NULL, NULL, DS_TRY_NEXTCLOSEST_SITE, &dci);
if (nStatus != NERR_Success)
{
dwError = GetLastError();
wprintf(L"DsGetDcName failed, reason: %d\n", dwError);
goto cleanup;
}
for (it = xl.begin(); it != xl.end(); ++it)
{
wcout << L"================GUID Extension: " << it->c_str() << L" ====================" << endl;
if (string_to_guid(it->c_str(), &guid) != 0)
{
wcout << L"Error - could not convert: " << it->c_str() << L" to UUID" << endl;
continue;
}
//Enumerate through all the local machine policies...
if (GetGPOList(NULL, buff, dci->DomainControllerName, buff, GPO_LIST_FLAG_MACHINE, &pGPOList))
{
PGROUP_POLICY_OBJECT pGPO = (PGROUP_POLICY_OBJECT)pGPOList;
while (pGPO != NULL)
{
//Display properties of each GPO
DisplayPolicyInfo(pGPO);
pGPO = pGPO->pNext;
}
FreeGPOList(pGPOList);
}
else
{
dwError = GetLastError();
DisplayError(dwError);
}
}
cleanup:
NetApiBufferFree(&dci);
return dwError;
}
/// <summary>
/// DisplayAppliedMachinePolicies
///
/// This function assumes the computer we analyze is the local computer
/// from where the code runs. You can specify a remote computer by changing
/// the 2nd argument to GetAppliedGPOList which is set to NULL by default.
/// </summary>
/// <returns></returns>
static DWORD DisplayAppliedMachinePolicies(ExtensionList& xl)
{
PGROUP_POLICY_OBJECT pGPOList = NULL;
LPGROUPPOLICYOBJECT pGPO = NULL;
UUID guid;
DWORD dwError = 0;
list<wstring>::iterator it;
for (it = xl.begin(); it != xl.end(); ++it)
{
wcout << L"================GUID Extension: " << it->c_str() << L" ====================" << endl;
if (string_to_guid(it->c_str(), &guid) != 0)
{
wcout<<L"Error - could not convert: " << it->c_str() << L" to UUID" <<endl;
continue;
}
dwError = GetAppliedGPOList(GPO_LIST_FLAG_MACHINE, NULL, NULL, &guid, &pGPOList);
if (dwError == ERROR_SUCCESS)
{
PGROUP_POLICY_OBJECT pGPO = (PGROUP_POLICY_OBJECT)pGPOList;
if (pGPO == NULL)
{
wcout << L"The " << it->c_str() << L" gpo extension did not contain any applied GPOs" << endl;
}
while (pGPO != NULL)
{
//Display properties of each GPO
DisplayPolicyInfo(pGPO);
pGPO = pGPO->pNext;
}
FreeGPOList((PGROUP_POLICY_OBJECT)pGPOList);
pGPOList = NULL;
}
else
{
wcout << L"Error - GetAppliedGPOList for GUID " << it->c_str() << L" returned Win32 error code: " << dwError <<endl;
}
}
return dwError;
}
/// <summary>
/// DisplayUserPolicies
///
/// Note: The GetGPOList function retrieves the list of GPOs for the specified user or computer.
///
/// HANDLE hToken: A token for the user or computer, returned from the LogonUser, CreateRestrictedToken, DuplicateToken, OpenProcessToken,
/// or OpenThreadToken function. This token must have TOKEN_IMPERSONATE and TOKEN_QUERY access. For more information,
/// see Access Rights for Access-Token Objects and the following Remarks section.
/// LPCSTR lpFQDN: A pointer to the user or computer name, in the fully qualified distinguished name format
/// (for example, "CN=user, OU=users, DC=contoso, DC=com").
/// LPCSTR hpHost: A DNS domain name (preferred) or domain controller name. Domain controller name can be retrieved using
/// the DsGetDcName function, specifying DS_DIRECTORY_SERVICE_REQUIRED in the flags parameter.
/// If the hToken parameter is not NULL, this parameter must be NULL.
///
/// LPCSTR lpComputerName: if this is NULL, the local computer name is used
/// </summary>
/// <returns></returns>
static DWORD DisplayUserPolicies(ExtensionList& xl, LPCWSTR lpComputerName)
{
HRESULT hr;
PGROUP_POLICY_OBJECT pGPOList;
LPGROUPPOLICYOBJECT pGPO = NULL;
EXTENDED_NAME_FORMAT enf = NameFullyQualifiedDN;
LPCWSTR lpDcName = NULL;
UUID guid;
PDOMAIN_CONTROLLER_INFO dci;
WCHAR fqdnBuffer[MAX_PATH] = { 0 };
DWORD dwSz = sizeof(WCHAR) * sizeof(fqdnBuffer);
DWORD dwError = ERROR_SUCCESS;
list<wstring>::iterator it;
if (!GetUserNameEx(enf,(LPWSTR)fqdnBuffer, &dwSz))
{
dwError = GetLastError();
wprintf(L"GetUserNameEx failed, reason: %d\n", dwError);
return dwError;
}
NET_API_STATUS nStatus = DsGetDcName(NULL, NULL, NULL, NULL, DS_DIRECTORY_SERVICE_REQUIRED, &dci);
if (nStatus != NERR_Success)
{
dwError = GetLastError();
wprintf(L"DsGetDcName failed, reason: %d\n", dwError);
goto cleanup;
}
for (it = xl.begin(); it != xl.end(); ++it)
{
wcout << L"================GUID Extension: " << it->c_str() << L" ====================" << endl;
if (string_to_guid(it->c_str(), &guid) != 0)
{
wcout << L"Error - could not convert: " << it->c_str() << L" to UUID" << endl;
continue;
}
//Enumerate through all the local user policies. We do this by not specifying GPO_LIST_FLAG_MACHINE
//for the dwFlags argument (5th).
if(GetGPOList(NULL, fqdnBuffer, dci->DomainControllerName, lpComputerName, NULL, &pGPOList))
{
PGROUP_POLICY_OBJECT pGPO = pGPOList;
while (pGPO != NULL)
{
//Display properties of each GPO
DisplayPolicyInfo(pGPO);
pGPO = pGPO->pNext;
}
FreeGPOList(pGPOList);
}
else
{
dwError = GetLastError();
wcout << L"Error - GetAppliedGPOList for GUID " << it->c_str() << L" returned Win32 error code: " << dwError << endl;
}
}
cleanup:
NetApiBufferFree(&dci);
return dwError;
}
/// <summary>
/// DisplayAppliedUserPolicies
///
/// These are the applied policies objects (GPOs) for the provided trustee.
///
/// </summary>
/// <param name="xl">The list of Group Policy extensions to process</param>
/// <param name="trustee">FQDN in the domain\user format</param>
/// <returns></returns>
static DWORD DisplayAppliedUserPolicies(ExtensionList& xl, LPCWSTR trustee)
{
PGROUP_POLICY_OBJECT pGPOList = NULL;
LPGROUPPOLICYOBJECT pGPO = NULL;
UUID guid;
DWORD dwDomainNameSize = 0; //set size of domain string required
WCHAR* pwsDomain = NULL; //domain string pointer
DWORD dwError = 0;
DWORD size = MAX_PATH;
SID_NAME_USE SidType;
DWORD SidLen = 0;
BYTE* lpDC = NULL; // DC Name, if necessary
DWORD dwSidSize = 0; //set size of SID required
SID_NAME_USE sidType; //not used yet
PSID pSid = NULL;
list<wstring>::iterator it;
//We need to lookup the account name and get the SID, for this we will use a DC.
if (NetGetAnyDCName(NULL, NULL, &lpDC) == NERR_Success)
{
if (!LookupAccountName(LPCWSTR(lpDC), trustee, NULL, &dwSidSize, NULL, &dwDomainNameSize, &sidType))
{
//Specify SID and Domain Cache sizes
pSid = (PSID)LocalAlloc(LPTR, dwSidSize); //allocate mem for SID object
if (!pSid)
return ERROR_NOT_ENOUGH_MEMORY;
pwsDomain = (PWSTR) new PWSTR[dwDomainNameSize + 1]; //allocate mem for domain name string
if (!pwsDomain)
return ERROR_NOT_ENOUGH_MEMORY;
}
else
{
//should never happen...
wcout << L"Unknown error on 1st LookupAccountName API call." << endl;
return ERROR_UNIDENTIFIED_ERROR;
}
//Note: above allocations will be De-allocated in cleanUp() function.
if (!LookupAccountName(LPCWSTR(lpDC), trustee, pSid, &dwSidSize, pwsDomain, &dwDomainNameSize, &sidType))
{
dwError = GetLastError();
wcout << L"Error on 2nd LookupAccountName API call " << dwError << endl;
goto cleanup;
}
//Check that SID returned is valid
if (!IsValidSid(pSid))
{
dwError = GetLastError();
wcout << L"SID validation error: " << dwError << L" ,cannot process SID and therefore exiting function." << endl;
goto cleanup;
}
}
else
{
dwError = GetLastError();
wcout << L"NetGetAnyDCName failed with error: " << dwError << L" ,cannot process SID and therefore exiting function." << endl;
return dwError;
}
for (it = xl.begin(); it != xl.end(); ++it)
{
wcout << L"================GUID Extension: " << it->c_str() << L" ====================" << endl;
if (string_to_guid(it->c_str(), &guid) != 0)
{
wcout << L"Error - could not convert: " << it->c_str() << L" to UUID" << endl;
continue;
}
dwError = GetAppliedGPOList(0, NULL, pSid, &guid, &pGPOList);
if (dwError == ERROR_SUCCESS)
{
PGROUP_POLICY_OBJECT pGPO = (PGROUP_POLICY_OBJECT)pGPOList;
while (pGPO != NULL)
{
//Display properties of each GPO
DisplayPolicyInfo((PGROUP_POLICY_OBJECT)pGPO);
pGPO = pGPO->pNext;
}
FreeGPOList((PGROUP_POLICY_OBJECT)pGPOList);
}
else
{
wcout << L"GetAppliedGPOList API error: " << dwError << L" for GUID extension: "<< it->c_str() << endl;
}
}
cleanup:
if (pSid)
LocalFree(pSid);
if (pwsDomain != NULL)
delete []pwsDomain;
return dwError;
}
/// <summary>
/// string_to_guid
/// </summary>
/// <param name="str"></param>
/// <param name="uuid"></param>
/// <returns></returns>
static int string_to_guid(wstring s, UUID* uuid)
{
//string off leading and trailing {}'s
//removeCharsFromString(s, (wchar_t*)L"{}");
removeBraces(s);
RPC_STATUS status = UuidFromString((RPC_WSTR)s.c_str(), uuid);
return (status == RPC_S_OK) ? 0 : 1;
}
static void removeCharsFromString(wstring& str, wchar_t* charsToRemove)
{
for (unsigned int i = 0; i < wcslen(charsToRemove); ++i)
{
str.erase(remove(str.begin(), str.end(), charsToRemove[i]), str.end());
}
}
/// <summary>
/// removeBraces
/// </summary>
/// <param name="str"></param>
static void removeBraces(wstring& str)
{
wstring::iterator it;
it = str.begin();
str.erase(it);
it = str.end();
--it;
str.erase(it);
}
/// <summary>
/// DisplayPolicyInfo
/// </summary>
/// <param name="pGPO"></param>
static void DisplayPolicyInfo(PGROUP_POLICY_OBJECT pGPO)
{
// Display details of the Group Policy Object
wcout<<L" ==== Group Policy =====" <<endl;
wcout << L"GPO Display Name: " << pGPO->lpDisplayName << endl;
wcout<<L"GPO Unique Name: " << pGPO->szGPOName <<endl;
wcout<<L"GPO Path: " << pGPO->lpFileSysPath <<endl;
wcout <<L"GPO Version: " << pGPO->dwVersion << endl;;
wcout<<L"GPO DS Path: " << pGPO->lpDSPath<< endl;
wcout<<L"GPO Extensions: " << pGPO->lpExtensions<< endl;
wcout << L"GPO Link: " << pGPO->lpLink << endl;
wcout << L"GPO Options: " << pGPO->dwOptions << endl;
}
The RPC server is unavailable
Please make sure your names are correct. for example:
[in] lpNameA pointer to the user or computer name, in the fully qualified distinguished name format (for example, "CN=user, OU=users, DC=contoso, DC=com").
But it deserves a new question.
Please mark answer for completion of the question if it's resolved.
I did a loop on keys at "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\GPExtensions"(RegOpenKeyEx/RegEnumKey)
and I got some != NULL
(
{35378EAC-683F-11D2-A89A-00C04FBBCFA2}
or
{F312195E-3D9D-447A-A3F5-08DFFA24735E}
on my PC)
I'll try those GUIDs and see if they work - thanks! I will also look through the list of available GUIDs as well.
This is the quick test I did (I have put a BP on the line
FreeGPOList(pGPOList);
to check not NULL pGPOList)
=>
{
LONG nResult;
DWORD nKeyIdx = 0;
WCHAR wsRegBuffer[MAX_PATH + 1] = L"";
HKEY hKey = NULL;
BOOL(FAR STDAPICALLTYPE* pGUIDFromString)(LPCTSTR psz, LPGUID pguid) = NULL;
HMODULE hInstance = LoadLibrary(L"Shell32.dll");
if (hInstance)
{
(FARPROC&)pGUIDFromString = GetProcAddress(hInstance, (LPCSTR)MAKEINTRESOURCE(704));
FreeModule(hInstance);
}
if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, L"SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Winlogon\\GPExtensions", 0, KEY_READ | KEY_WOW64_64KEY, &hKey) == ERROR_SUCCESS)
{
while (TRUE)
{
nResult = RegEnumKey(hKey, nKeyIdx, wsRegBuffer, ARRAYSIZE(wsRegBuffer));
if (nResult == ERROR_NO_MORE_ITEMS)
{
break;
}
else
{
PGROUP_POLICY_OBJECT pGPOList = NULL;
GUID guid;
BOOL bRet = pGUIDFromString(wsRegBuffer, &guid);
// pGPOList != NULL
// {35378EAC-683F-11D2-A89A-00C04FBBCFA2}
// {F312195E-3D9D-447A-A3F5-08DFFA24735E}
DWORD nError = GetAppliedGPOList(GPO_LIST_FLAG_MACHINE, NULL, NULL, &guid, &pGPOList);
if (nError == ERROR_SUCCESS && pGPOList != NULL)
{
// Code...
FreeGPOList(pGPOList);
}
}
++nKeyIdx;
}
RegCloseKey(hKey);
}
}
Thanks Castorix31, that was very helpful. I will add that to my code. I've finally been able to look at the GPO's from the list and print out their information. When I am done I will post the code.