Security issue with .desktop files revisited

[Joerg Barfurth]

Thiago Macieira wrote:
> We could abuse the sticky bit for that. What's also interesting, it would 
> show a "t" or "T" in the output of ls -l.
> 
> It has no effect on text files on Linux, nor on executables. However, the 
> man page for "chmod" says that, on some systems, only the superuser can 
> set the sticky bit. Does anyone know what such systems might be?
> 

 From Solaris man-pages:

chmod(1):
      [...] Only  the  super-user  may
      set  the sticky bit on a non-directory file.
      If you are not super-user, chmod  will  mask
      the sticky-bit but will not return an error.

chmod(2):
      If the process is not a privileged process and the  file  is
      not  a  directory, mode bit 01000 (save text image on execu-
      tion) is cleared.
      [...]
      If a regular file is not executable and has S_ISVTX set, the
      file  is  assumed  to  be  a  swap  file.  In this case, the
      system's page cache will not be  used  to  hold  the  file's
      data.  If  the  S_ISVTX  bit  is  set on any other file, the
      results are unspecified.

So neither does this bit have no effect, nor can it be set by ordinary 
users.

I'd assume other Unixes with a common ancestor would behave similarly.


- Jörg


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Joerg Barfurth           phone: +49 40 23646662 / x66662
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