netdev - Re: iproute2 (addr flush) infinite loop when unprivileged users

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Message-ID: <9e0cf0bf0801251506qc651075gd2fb9e21ddbe45bd@mail.gmail.com>
Date:	Sat, 26 Jan 2008 01:06:17 +0200
From:	"Alon Bar-Lev" <alon.barlev@...il.com>
To:	"Stephen Hemminger" <shemminger@...ux-foundation.org>
Cc:	netdev@...r.kernel.org
Subject: Re: iproute2 (addr flush) infinite loop when unprivileged users

Thanks for quick response!
I tried to figure out how to do this, it looks like the libnelink does
this anyway...
I must missed something.
Can you please help?

On 1/26/08, Stephen Hemminger <shemminger@...ux-foundation.org> wrote:
> On Sat, 26 Jan 2008 01:00:34 +0200
> "Alon Bar-Lev" <alon.barlev@...il.com> wrote:
>
> > Hello,
> >
> > When executing the following command using unprivileged users there is
> > an infinite loop...
> > /sbin/ip route flush dev eth1
> >
> > Execution with -s produces:
> > *** Round 28153, deleting 2 entries ***
> >
> > *** Round 28154, deleting 2 entries ***
> >
> > *** Round 28155, deleting 2 entries ***
> >
> > *** Round 28156, deleting 2 entries ***
> >
> > *** Round 28157, deleting 2 entries ***
> >
> > *** Round 28158, deleting 2 entries ***
> >
> > *** Round 28159, deleting 2 entries ***
> >
> > I do not fully understand the sequence, but it may be kernel fault, as
> > it should have returned EPERM for this request stopping the netlink
> > request.
> >
> > Anyway... A simple solution is to store the filter.flushed and fail if
> > it keeps its value during loop iteration at
> > ip/ipaddress.c::ipaddr_list_or_flush(), but this is only a
> > workaround...
> >
> > Please CC as I am not in netdev list.
> > Thanks!
> > Alon.
>
> Non privileged users can't delete routes, but command keeps trying.
> The correct way to handle it is to teach flush loop to look at error code.
>
> --
> Stephen Hemminger <stephen.hemminger@...tta.com>
>
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