Re: /proc filesystem allows bypassing directory permissions on Linux

[Dan Yefimov <dan () lightwave net ru>]

On 26.10.2009 18:14, nomail () nomail com wrote:
> > > I do not think mounting /proc should change access control semantics.
> > It didn't in fact change anything. If the guest created hardlink to that file in
>> a unrestricted location, what would you say?
> Do your homework and test it. You can't create the hardlink - the link(oldpath,
> newpath) call will fail with EACCES if search permission is denied for any
> directory in oldpath or newpath. Documented in the manpage, and I just tested
> and verified it.
>
Good boy. However, there wasn't worth both citing well known facts to me and 
testing them. Remember the scenario from the original mail and try finding a 
window, during which creating a hardlink would still work thus evading directory 
permissions check.
--

Sincerely Your, Dan.