Re: Valid characters on one o/s are invalid on another

From: Craig Boston (craigat_private)
Date: Mon Jun 25 2001 - 14:06:19 PDT

  • Next message: Sander Smeenk (CistroN Medewerker): "Re: Valid characters on one o/s are invalid on another"

    That reminds me of something funny I noticed when using cyrus-imapd and having
    it store the files on a remote smbfs mount (I'm insane, I know).  Try
    something like this sometime from a *nix box:
    
    smbclient \\\\ntserver\\share
    smb: \> put deleteme
    smb: \> ren deleteme deleteme.
    smb: \> quit
    
    On the NT server you now have a file whose name ends in a single dot (pay
    close attention to the ren line with the dot at the end).  Apparently this is
    an illegal filename as far as Windows is concerned and you won't be able to do
    anything with the file from Windows.  You can't open it, delete it, rename it,
    or do anything to it from either the shell or command-line.  The only way I
    know of to get rid of the file is to use smbclient again, or use rd /s to nuke
    the entire directory (deleting the folder from the GUI won't work).
    
    I know this works against NT/2k servers on NTFS volumes.  I didn't think much
    of it at the time and have not done any testing with 9x file sharing or FAT
    volumes, so YMMV.
    
    The funny thing is that even though virtually no file system tool is able to
    so much as print the contents of the file, ntbackup has no problem backing up
    and restoring it.
    
    Craig
    
    ----- Original Message -----
    From: "Kayne Ian (Softlab)" <Ian.Kayneat_private>
    To: "Vuln-Dev" <VULN-DEVat_private>
    Sent: Monday, June 25, 2001 3:15 AM
    Subject: Valid characters on one o/s are invalid on another
    
    
    Hey all,
    This recent thread about antivirus scanners & DOS archives got me
    thinking. Years ago (before *zip introduced the non-absolute paths option),
    it was possible to create a zip archive with some files in, hex edit the
    archive and change the locations of some of these files, thus making it
    extremely easy to transparently replace files on a system that the archive
    is extracted on. This used to be a particularly nasty trick on amiga bbs's -
    the amiga version of zip was pretty pathetic to say the least. Anyway, this
    got me wondering about seeing whether this was still possible (albeit in a
    different manner). After playing around, I noticed something strange.
    
    We all know Windows (well the FS really) doesn't allow certain ascii
    characters to be used for filenames - ?, " etc... But, other o/s's
    filesystems do - in this case Amiga O/S 3.0 & the FFS (fast file system).
    So, when I got a CD on the amiga containing some files with legal characters
    under workbench but illegal under windows, then tried to access the CD on a
    windows machine (specifically the badly named files), some dodgy behaviour
    happened. Files started "dissapearing" from the CD etc... Didn't go much
    further than this...
    
    Just wondering if anyone else has any thoughts/opinions on this ...
    Is it even any use or worth looking into?
    
    Ian Kayne
    Technical Specialist - IT Solutions
    Softlab Ltd - A BMW Company
    
    
    
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