Mega Code Archive
Converting a SID to a string
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Title: Converting a SID to a string
Question: I've seen quite a few people ask how to convert a Security Identifier (SID) into a human-readable string. Since I was not able to find much help on the subject on newsgroups/etc., I decided to post some example code..
Answer:
Here are some wrappers and helper functions to make your life easier:
...
const
SID_REVISION = 1;
FILENAME_ADVAPI32 = 'ADVAPI32.DLL';
PROC_CONVERTSIDTOSTRINGSIDA = 'ConvertSidToStringSidA';
type
TConvertSidToStringSidA = function (Sid: PSID;
var StringSid: LPSTR): BOOL; stdcall;
function WinGetSidStr (Sid : PSid) : string;
var
SidToStr : TConvertSidToStringSidA;
h : LongWord;
Buf : array [0..MAX_PATH - 1] of char;
p : PAnsiChar;
begin
h := LoadLibrary (FILENAME_ADVAPI32);
if h 0 then
try
@SidToStr := GetProcAddress (h, PROC_CONVERTSIDTOSTRINGSIDA);
if @SidToStr nil then
begin
FillChar (Buf, SizeOf(Buf), 0);
if SidToStr (Sid, p) then
Result := '[' + string(p) + ']';
LocalFree (LongWord(p));
end;
finally
FreeLibrary (h);
end;
end;
function GetSidStr (Sid : PSid) : string;
var
Psia : PSIDIdentifierAuthority;
SubAuthCount : LongWord;
i : LongWord;
begin
if IsValidSid (Sid) then
begin
//
// Win 2000+ contains ConvertSidToStringSidA() in advapi32.dll so we just
// use it if we can
//
if (Win32Platform = VER_PLATFORM_WIN32_NT) and
(Win32MajorVersion = 5) then
Result := WinGetSidStr (Sid)
else
begin
Psia := GetSidIdentifierAuthority (Sid);
SubAuthCount := GetSidSubAuthorityCount (Sid)^;
Result := Format('[S-%u-', [SID_REVISION]);
if ((Psia.Value[0] 0) or (Psia.Value[1] 0)) then
Result := Result + Format ('%.2x%.2x%.2x%.2x%.2x%.2x', [Psia.Value[0],
Psia.Value[1], Psia.Value[2], Psia.Value[3], Psia.Value[4],
Psia.Value[5]])
else
Result := Result + Format ('%u', [LongWord(Psia.Value[5]) +
LongWord(Psia.Value[4] shl 8) + LongWord(Psia.Value[3] shl 16) +
LongWord(Psia.Value[2] shl 24)]);
for i := 0 to SubAuthCount - 1 do
Result := Result + Format ('-%u', [GetSidSubAuthority(Sid, i)^]);
Result := Result + ']';
end;
end;
end;
function GetLocalUserSidStr (const UserName : string) : string;
var
RefDomain : array [0..MAX_PATH - 1] of char; // enough
RefDomainSize : LongWord;
Snu : SID_NAME_USE;
Sid : PSid;
SidSize : LongWord;
begin
SidSize := 0;
RefDomainSize := SizeOf(RefDomain);
Sid := nil;
FillChar (RefDomain, SizeOf(RefDomain), 0);
LookupAccountName (nil, PChar(UserName), Sid, SidSize, RefDomain,
RefDomainSize, Snu);
Sid := AllocMem (SidSize);
try
RefDomainSize := SizeOf(RefDomain);
if LookupAccountName (nil, PChar(UserName), Sid, SidSize, RefDomain,
RefDomainSize, Snu) then
Result := GetSidStr (Sid);
finally
FreeMem (Sid, SidSize);
end;
end;
...
To get a local users SID string simply call GetLocalUserSidStr('SomeUserName');
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