Solved

ACCESS_MASK

Posted on 2008-10-20
4
507 Views
Last Modified: 2013-11-25
Hi,

How do I retrieve ACCESS_MASK from a file, or a file handle?
Thanks
0
Comment
Question by:mycuti08
  • 2
  • 2
4 Comments
 
LVL 41

Accepted Solution

by:
graye earned 500 total points
Comment Utility
The ACCESS_MASK is just the format for the Access Control Entries (ACE).   http://msdn.microsoft.com/en-us/library/aa374896.aspx
The ACE is inside the Discretionaly Access Control List (ACL).   You'd typically use GetNamedSecurityInfo to get the DACL, then "walk the DACL" to get each ACE.   There is an example that sets the ACE at the following link.   It not exactly what you're looking for, but it's a pretty good example of the technique required:  http://msdn.microsoft.com/en-us/library/aa379283(VS.85).aspx
0
 

Author Comment

by:mycuti08
Comment Utility
Thanks graye,

I got to the point where I can get the pointer to PDACL. But that pointer only points to the ACL header, not a list of ACEs. How do I access list of ACEs from this point.

0
 

Author Closing Comment

by:mycuti08
Comment Utility
I got it. Thanks
0
 
LVL 41

Expert Comment

by:graye
Comment Utility
I've got a VB.Net example handy...   (Sorry, I don't have C++ version, but it still might be helpful)

    Public Function GetFileACL(ByVal file As String) As ACE_Entry()

        Dim SD As System.IntPtr

        Dim SDSizeNeeded, SDSize As Integer

        Dim LastError As Integer

        Dim Dacl_Present, Dacl_Defaulted As Boolean

        Dim DACL, ACE, SID_ptr, SID_String_ptr As System.IntPtr

        Dim ACE_Header As ACE_HEADER

        Dim Access_ACE As ACCESS_ACE

        Dim ACL_size As ACL_SIZE_INFORMATION

        Dim ACL_Rev As ACL_REVISION_INFORMATION

        Dim entry As Integer

        Dim isFile As Boolean

        Dim Win32Error As Win32Exception

        Dim name_len, domain_len, dUse, num As Integer

        Dim name, domain_name, UserName, MachineName, StringSID As String

        Dim Ans(0) As ACE_Entry
 

        ' Do a quick sanity check?

        isFile = True

        If System.IO.File.Exists(file) = False Then

            If System.IO.Directory.Exists(file) = False Then

                Throw New ApplicationException("Error: file doesn't exist!")

            End If

            isFile = False

        End If
 

        ' get the Security Descriptor and DACL

        If GetNamedSecurityInfo(file, SE_FILE_OBJECT, DACL_SECURITY_INFORMATION, Nothing, Nothing, DACL, Nothing, SD) <> 0 Then

            LastError = Marshal.GetLastWin32Error()

            Win32Error = New Win32Exception(LastError)

            Throw New ApplicationException("Error: " & Win32Error.Message)

        End If
 

        ' quick sanity check...

        If IsValidSecurityDescriptor(SD) = False Then

            Throw New ApplicationException("Error: invalid SD")

        End If
 

        ' one last check...

        If IsValidAcl(DACL) = False Then

            Throw New ApplicationException("Error: invalid ACL")

        End If
 

        ' how many ACEs are in the DACL?

        GetAclInformation(DACL, ACL_size, Len(ACL_size), ACL_INFORMATION_CLASS.AclSizeInformation)

        ReDim Ans(ACL_size.AceCount - 1)

        Debug.WriteLine("AceCount=" & ACL_size.AceCount)
 

        GetAclInformation(DACL, ACL_Rev, Len(ACL_Rev), ACL_INFORMATION_CLASS.AclRevisionInformation)

        Debug.WriteLine("ACL_Rev=" & ACL_Rev.AclRevision)
 

        ' loop thru all of the ACE's in the DACL

        entry = 0

        Do While GetAce(DACL, entry, ACE) = True

            ' start by copying just the header

            ACE_Header = Marshal.PtrToStructure(ACE, GetType(ACE_HEADER))
 

            ' we're really only interested in type=0 (allow) and type=1 (deny)

            If ACE_Header.AceType = 0 Or ACE_Header.AceType = 1 Then

                ' now that we know it's type... we do the copy over again

                Access_ACE = Marshal.PtrToStructure(ACE, GetType(ACCESS_ACE))
 

                Debug.WriteLine("AceSize=" & ACE_Header.AceSize & ", AceType=" & ACE_Header.AceType & ", Mask=" & Access_ACE.Mask & ", AceFlags=" & Access_ACE.Header.AceFlags)
 

                ' translate SID to Account Name

                SID_ptr = New IntPtr(ACE.ToInt32 + 8)

                UserName = TranslateSidToName("", SID_ptr)

                Ans(entry).ACE_Name = Left(UserName, 50)
 

                ' Type of ACE

                If ACE_Header.AceType = 0 Then

                    Ans(entry).ACE_Type = "Allow"

                Else

                    Ans(entry).ACE_Type = "Deny"

                End If
 

                ' the permissions

                If isFile Then

                    Ans(entry).ACE_Permission = FileMaskToString(Access_ACE.Mask)

                Else

                    Ans(entry).ACE_Permission = DirectoryMaskToString(Access_ACE.Mask)

                End If
 

                ' Inheritance

                If Access_ACE.Header.AceFlags And AceFlags.INHERITED_ACE Then

                    Ans(entry).ACE_Inherited = True

                Else

                    Ans(entry).ACE_Inherited = False

                End If
 

                ' Scope (directories only)

                If isFile = False Then

                    Ans(entry).ACE_Scope = ACEFlagToString(Access_ACE.Header.AceFlags)

                End If

            End If

            entry = entry + 1

        Loop
 

        ' Free the memory we allocated.

        'Marshal.FreeHGlobal(SD)
 

        ' Exit the routine.

        If entry > 0 Then

            ReDim Preserve Ans(entry - 1)

        End If

        Return Ans

    End Function

Open in new window

0

Featured Post

Do You Know the 4 Main Threat Actor Types?

Do you know the main threat actor types? Most attackers fall into one of four categories, each with their own favored tactics, techniques, and procedures.

Join & Write a Comment

Introduction: Ownerdraw of the grid button.  A singleton class implentation and usage. Continuing from the fifth article about sudoku.   Open the project in visual studio. Go to the class view – CGridButton should be visible as a class.  R…
Introduction: Dialogs (1) modal - maintaining the database. Continuing from the ninth article about sudoku.   You might have heard of modal and modeless dialogs.  Here with this Sudoku application will we use one of each type: a modal dialog …
This video will show you how to get GIT to work in Eclipse.   It will walk you through how to install the EGit plugin in eclipse and how to checkout an existing repository.
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

13 Experts available now in Live!

Get 1:1 Help Now