Re: make ping executable by normal users?
On Mon 06 Jun 2016 at 18:11:27 (+0200), Norbert Kiszka wrote:
> Dnia 2016-06-06, pon o godzinie 11:00 -0500, David Wright pisze:
> > On Mon 06 Jun 2016 at 15:27:16 (+0000), Mark Fletcher wrote:
> > > On Mon, 6 Jun 2016 at 23:15, Santiago Vila <sanvila@unex.es> wrote:
> > >
> > > > On Mon, Jun 06, 2016 at 10:06:54AM +1200, Jan Bakuwel wrote:
> > > > > Check your firewall rules.
> > > >
> > > > It can't be firewall rules. Try this to block outgoing ping:
> > > >
> > > > iptables -A OUTPUT -p icmp --icmp-type echo-request -j REJECT
> > > >
> > > > then try to ping anywhere. You will get a different error message,
> > > > namely "Destination Port Unreachable".
> > > >
> > > > [ Why people do not read all messages in the thread before answering
> > > > is a mystery to me ].
> >
> > > No, that's not true, you definitely can get this very error due to
> > > something to do with the firewall, maybe it's not able to resolve the ping
> > > target rather than not able to reach the resulting host, I'm damned if I
> > > can remember the specifics but I've definitely seen this happen on an lfs
> > > box before and it was nothing to do with perms (as I said before, to your
> > > point about people not reading the whole thread...)
> >
> > I don't understand this argument.
> >
> > Why would ping bother to open a socket to a host it couldn't resolve?
> >
> > I know precious little about firewall rules, but AIUI the rules
> > determine whether to respond with things like Drop, Reject, Deny.
> > Now the OP didn't manage to open a socket; that's in the error message:
> > "ping: icmp open socket: Operation not permitted"
> > So how would ping find out how the firewall was going to react to its
> > ping message without opening a socket to send something?
>
> Did You change linux kernel, kernel modules or something lastly?
I now know even less about what you're talking about. I don't have a
problem. I have easily duplicated the OP's error message in the
following way:
$ cp -ip /bin/ping /tmp
$ /tmp/ping alum.local
ping: icmp open socket: Operation not permitted
$ /sbin/getcap /tmp/ping
$ /sbin/getcap /bin/ping
/bin/ping = cap_net_raw+ep
$
That's jessie. On wheezy:
$ ls -l /bin/ping /tmp/ping
-rwsr-xr-x 1 root root 31104 Apr 12 2011 /bin/ping
-rwxr-xr-x 1 david david 31104 Apr 12 2011 /tmp/ping
Cheers,
David.
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