Windows Access Control List (ACL) Example 27

 

 

 

 

Finding the Owner of a File Object Program Example

 

The following example uses the GetSecurityInfo() and LookupAccountSid() functions to find and print the name of the owner of a file.  The file exists in C:\JohnnyDir directory on the local machine. The file own by Johnny, however the computer used to run this program logged as Mike spoon.

Create a new empty Win32 console application project. Give a suitable project name and change the project location if needed.

 

 

Then, add the source file and give it a suitable name.

 

 

Next, add the following source code.

 

// Finding the Owner of a File Object

#include <windows.h>

#include <stdio.h>

#include <aclapi.h>

 

int wmain(int argc, WCHAR *argv[])

{

      DWORD dwRtnCode = 0;

      PSID pSidOwner;

      BOOL bRtnBool = TRUE;

      // Dummy initial value, no string...

      LPTSTR AcctName = L, DomainName = L;

      DWORD dwAcctName = 1, dwDomainName = 1;

      // Dummy initial value, just use the defined one but unknown

      SID_NAME_USE eUse = SidTypeUnknown;

      HANDLE hFile;

      PSECURITY_DESCRIPTOR pSD = {0};

     

      // Get the handle of the file object.

      hFile = CreateFile(

            L\\\\?\\C:\\JohnnyDir\\ThisisJohnnyfile.txt,  // The file name and the path if any

            GENERIC_READ,                 // Access right

            FILE_SHARE_READ,        // Share mode

            NULL,                         // Security attribute for inherited or not by child

            OPEN_EXISTING,                // Open the file, fail if not exist

            FILE_ATTRIBUTE_NORMAL,  // file attribute flag, Normal

            NULL);                              // Handle to template file if GENERIC_READ right access

     

      // Verify

      if(hFile == INVALID_HANDLE_VALUE)

      {

            wprintf(LCreateFile() failed, error = %u\n, GetLastError());

            // Just exit, 0 - OK, non-zero - failed

            return -1;

      }

      else

            wprintf(LGot the handle to the file!\n);

     

      // Allocate memory for the SID structure.

      wprintf(LAllocating buffer for pSidOwner & pSD\n);

      pSidOwner = (PSID)GlobalAlloc(GMEM_FIXED, sizeof(PSID));

      // Allocate memory for the security descriptor structure.

      pSD = (PSECURITY_DESCRIPTOR)GlobalAlloc(GMEM_FIXED, sizeof(PSECURITY_DESCRIPTOR));

     

      // Get the owner SID of the file. Try for other object such as

      // SE_SERVICE, SE_PRINTER, SE_REGISTRY_KEY, SE_KERNEL_OBJECT, SE_WINDOW_OBJECT etc.

      // for 2nd parameter and 3rd parameter such as DACL_SECURITY_INFORMATION,

      // GROUP_SECURITY_INFORMATION and SACL_SECURITY_INFORMATION

      dwRtnCode = GetSecurityInfo(

            hFile,// Handle to the file

            SE_FILE_OBJECT,// Directory or file

            OWNER_SECURITY_INFORMATION, // Owner information of the (file) object

            &pSidOwner,// Pointer to the owner of the (file) object

            NULL,

            NULL,

            NULL,

            &pSD);// Pointer to the security descriptor of the (file) object

     

      // Check GetLastError for GetSecurityInfo error condition.

      if(dwRtnCode != ERROR_SUCCESS)

      {

            wprintf(LGetSecurityInfo() failed, error %u\n, GetLastError());

            return -1;

      }

      else

            wprintf(LGetSecurityInfo() - Got the SID of the file!\n);

     

      // First call to LookupAccountSid() to get the buffer size AcctName.

      bRtnBool = LookupAccountSid(

            NULL,             // Local computer

            pSidOwner,        // Pointer to the SID to lookup for

            AcctName,         // The account name of the SID (pSIDOwner)

            (LPDWORD)&dwAcctName,   // Size of the AcctName in TCHAR

            DomainName,       // Pointer to the name of the Domain where the account name was found

            (LPDWORD)&dwDomainName, // Size of the DomainName in TCHAR

            &eUse);                 // Value of the SID_NAME_USE enum type that specify the SID type

     

      // Allocate memory for the AcctName.

      AcctName = (LPTSTR)GlobalAlloc(GMEM_FIXED, dwAcctName);

      // VErify

      if(AcctName == NULL)

      {

            wprintf(LGlobalAlloc() - Failed to allocate buffer for AcctName, error %u\n, GetLastError());

            return -1;

      }

      else

            wprintf(LBuffer allocated for AcctName!\n);

     

      DomainName = (LPTSTR)GlobalAlloc(GMEM_FIXED, dwDomainName);

     

      // Check GetLastError() for GlobalAlloc() error condition.

      if(DomainName == NULL)

      {

            wprintf(LGlobalAlloc() failed to allocate buffer for DomainName, error %u\n, GetLastError());

            return -1;

      }

      else

            wprintf(LBuffer allocated for DomainName!\n);

     

      // Second call to LookupAccountSid() to get the account name.

      bRtnBool = LookupAccountSid(

            NULL,       // name of local or remote computer

            pSidOwner,  // security identifier, SID

            AcctName,   // account name buffer

            (LPDWORD)&dwAcctName,         // size of account name buffer

            DomainName, // domain name

            (LPDWORD)&dwDomainName,       // size of domain name buffer

            &eUse);           // SID type

     

      // Verify

      if(bRtnBool == FALSE)

      {

            DWORD dwErrorCode = GetLastError();

           

            if(dwErrorCode == ERROR_NONE_MAPPED)

                  wprintf(LAccount owner not found for specified SID.\n);

            else

            {

                  wprintf(LLookupAccountSid() failed, error %u\n, GetLastError());

                  return -1;

            }

      }

      else if (bRtnBool == TRUE)

            // Print the account name.

            wprintf(LThe file owner: %s\n, AcctName);

     

      if(CloseHandle(hFile) != 0)

            wprintf(LhFile handle was closed successfully!\n);

      else

            wprintf(LFailed to close hFile handle, error %u\n, GetLastError());

 

      return 0;

}

 

Build and run the project. The following screenshot is a sample output.

 

 

Then, let verify through the ThisisJohnnyfile.txt file property page and it confirmed that the owner is a local user Johnny.

 

 

 

 

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