FILESEC.CXX

//+------------------------------------------------------------------ 
// 
// Copyright (C) 1995, Microsoft Corporation. 
// 
// File:        filesec.cxx 
// 
// Classes:     CFileSecurity class encapsulating SECURITY_DESCRIPTOR 
// 
// History:     Nov-93      DaveMont         Created. 
// 
//------------------------------------------------------------------- 
 
#include <filesec.hxx> 
//+--------------------------------------------------------------------------- 
// Function:    Add2Ptr 
// 
// Synopsis:    Add an unscaled increment to a ptr regardless of type. 
// 
// Arguments:   [pv]-- Initial ptr. 
//              [cb]-- Increment 
// 
// Returns:     Incremented ptr. 
// 
//---------------------------------------------------------------------------- 
VOID * Add2Ptr(VOID *pv, ULONG cb) 
{ 
    return((BYTE *) pv + cb); 
} 
//+--------------------------------------------------------------------------- 
// 
//  Member:     CFileSecurity::CFileSecurity, public 
// 
//  Synopsis:   initializes data members 
//              constructor will not throw 
// 
//  Arguments:  [filename] - name of file to apply security descriptor to 
// 
//---------------------------------------------------------------------------- 
CFileSecurity::CFileSecurity(WCHAR *filename) 
    : _psd(NULL), 
      _pwfilename(filename) 
{ 
} 
//+--------------------------------------------------------------------------- 
// 
//  Member:     CFileSecurity::Init, public 
// 
//  Synopsis:   Init must be called before any other methods - this 
//              is not enforced.  gets security descriptor from file 
// 
//  Arguments:  none 
// 
//---------------------------------------------------------------------------- 
ULONG CFileSecurity::Init() 
{ 
    ULONG ret; 
    ULONG cpsd; 
 
    // get the size of the security buffer 
 
    if (!GetFileSecurity(_pwfilename, 
                         DACL_SECURITY_INFORMATION | 
                         GROUP_SECURITY_INFORMATION | 
                         OWNER_SECURITY_INFORMATION, 
                         NULL, 
                         0, 
                         &cpsd) ) 
    { 
        if (ERROR_INSUFFICIENT_BUFFER == (ret = GetLastError())) 
        { 
            if (NULL == (_psd = (BYTE *)LocalAlloc(LMEM_FIXED, cpsd))) 
            { 
                 return(ERROR_NOT_ENOUGH_MEMORY); 
            } 
 
            // actually get the buffer this time 
 
            if ( GetFileSecurity(_pwfilename, 
                                 DACL_SECURITY_INFORMATION | 
                                 GROUP_SECURITY_INFORMATION | 
                                 OWNER_SECURITY_INFORMATION, 
                                 _psd, 
                                 cpsd, 
                                 &cpsd) ) 
                ret = ERROR_SUCCESS; 
            else 
                ret = GetLastError(); 
 
        } 
    } else 
        return(ERROR_NO_SECURITY_ON_OBJECT); 
    return(ret); 
} 
//+--------------------------------------------------------------------------- 
// 
//  Member:     Dtor, public 
// 
//  Synopsis:   frees security descriptor if allocated 
// 
//  Arguments:  none 
// 
//---------------------------------------------------------------------------- 
CFileSecurity::~CFileSecurity() 
{ 
    if (_psd) 
    { 
        LocalFree(_psd); 
    } 
} 
 
//+--------------------------------------------------------------------------- 
// 
//  Member:     CFileSecurity::SetFS, public 
// 
//  Synopsis:   sets or modifies the security descriptor DACL on the specified file 
// 
//  Arguments:  IN - [fmodify] - TRUE = modify ACL, FALSE = replace ACL 
//              IN - [pcdw]    - wrapper around new ACEs 
//              IN - [fdir]    - TRUE = directory 
// 
//  Returns:    status 
// 
//---------------------------------------------------------------------------- 
ULONG CFileSecurity::SetFS(BOOL fmodify, CDaclWrap *pcdw, BOOL fdir) 
{ 
   BOOL fdaclpresent; 
   BOOL cod; 
   ACL *pdacl; 
   ULONG ret; 
 
   // get the ACL from the security descriptor 
 
   if ( GetSecurityDescriptorDacl(_psd, 
                                  &fdaclpresent, 
                                  &pdacl, 
                                  &cod) ) 
 
   { 
       if (fdaclpresent) 
       { 
           // build the new ACL (from the new ACEs and the old ACL) 
 
           ACL *pnewdacl = NULL; 
 
           if (ERROR_SUCCESS == (ret =  pcdw->BuildAcl(&pnewdacl, fmodify ? pdacl : NULL, pdacl ? pdacl->AclRevision : ACL_REVISION, fdir))) 
           { 
               // make a new security descriptor 
 
               SECURITY_DESCRIPTOR newsd; 
               newsd.Revision = ((SECURITY_DESCRIPTOR*) _psd)->Revision; 
               newsd.Sbz1 = 0; 
               newsd.Control = SE_DACL_PRESENT; 
               newsd.Owner = _psd + (ULONG)((SECURITY_DESCRIPTOR*)_psd)->Owner; // convert to absolute 
               newsd.Group = _psd + (ULONG)((SECURITY_DESCRIPTOR*)_psd)->Group; // convert to absolute 
               newsd.Sacl  = (ACL *) (_psd + (ULONG)((SECURITY_DESCRIPTOR*)_psd)->Sacl); // convert to absolute 
               newsd.Dacl = pnewdacl; 
 
               // apply it to the file 
 
               if (!SetFileSecurity(_pwfilename, 
                                    DACL_SECURITY_INFORMATION, 
                                    &newsd)) 
               { 
                   ret = GetLastError(); 
               } 
               LocalFree(pnewdacl); 
           } 
       } 
       else 
           return(ERROR_NO_SECURITY_ON_OBJECT); 
    } else 
    { 
        ret = GetLastError(); 
    } 
 
    return(ret); 
}