Unprivileged user?

Florian Engelhardt f.engelhardt at 21torr.com
Tue Apr 15 08:25:36 CEST 2008

On Mon, 14 Apr 2008 23:20:11 -0700
Ricardo Newbery <ric at digitalmarbles.com> wrote:

> On Apr 14, 2008, at 11:03 PM, Per Andreas Buer wrote:
> > Ricardo Newbery skrev:
> >> I'm trying to understand the purpose of the "-u user" option for
> >> varnishd.  It appears that even when starting up as root, and the
> >> child process dropping to "nobody", Varnish is still saving and
> >> serving from cache even though "nobody" doesn't have read/write  
> >> access
> >> to the storage file owned by root.
> >
> > In Unix, if you drop privileges, you still have access to all your  
> > open
> > files. Access control happens when you open files. That should
> > answer the rest of your questions too, I believe.
> 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?

Thats the same thing in apache, mysql, ...
Open every filehandle you need, then drop privileges. In case the
software is beeing hacked, it can not damage the system, only the
opened file pointers and everything the user can do. If the daemon
would run as root, the hacker could do everything with your computer.


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