Unprivileged user?

[Ricardo Newbery]

On Apr 14, 2008, at 11:25 PM, Per Andreas Buer wrote:

> Ricardo Newbery skrev:
>
>> Hmm... maybe I'm missing something but this doesn't seem to answer  
>> the
>> main question.  If, as you seem to imply, Varnish is opening any  
>> files
>> it needs while it's still "root", then what is the purpose of the "-u
>> user" option?
>
> I'm guessing Varnish (like most Unix daemons) opens the file as root  
> and
> then drops its privileges. That way, when Varnish deals with the
> untrusted data coming from the network it runs as an unprivileged  
> user.
>
> So, I there is a buffer overflow in Varnish, the code won't run with
> root privileges.
>
> Per.


Again, this is *not* my question.  Of course dropping privileges is a  
standard practice for daemons that need temporary elevated privileges.

But this does not explain the purpose that the "-u user" option serves  
in the Varnish case... other than perhaps to provide another option in  
case the standard default "nobody" is not available for some reason.

In Apache, the less-privileged user still needs read access to the  
files it serves.  In Squid, the less-privileged user still needs write  
access to the cache directory in order to create the cache storage.   
In Varnish, does the less-privileged user need access to anything?

Ric