Can I create a link to an inode?

Wayne Feick waf at brunz.org
Fri Aug 15 22:22:16 UTC 2008


I'd consider it a security bug to allow a user to see any bytes beyond
what was written to the file since:

     1. Some ilesystems store multiple small files in the same block.
     2. Some (most?) filesystems don't zero out blocks when they are
        reallocated.

Either of the above could allow you to see things you shouldn't.

Wayne.


On Fri, 2008-08-15 at 15:05 -0700, Konstantin Svist wrote:
> Patrick O'Callaghan wrote:
> > On Fri, 2008-08-15 at 13:42 -0500, Doug Wyatt wrote:
> >   
> >> I think I read, somewhere, that in doing that I could end up
> >> with garbage bytes at the end of the last block in the copy,
> >> and would need to use the size from the original inode to
> >> trim the copied file.  Don't know if that's fact or not.
> >>     
> >
> > I can't imagine why that would be true. A file is a file is a file.
> >   
> 
> The file doesn't occupy the entire last sector in most filesystems. 
> Maybe that's what was meant originally as garbage bytes - the whole file 
> is there, plus the (supposedly) empty remainder of the last sector.
> 
> 
> 




More information about the users mailing list