From owner-freebsd-multimedia Tue Apr 28 09:28:54 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id JAA29336 for freebsd-multimedia-outgoing; Tue, 28 Apr 1998 09:28:54 -0700 (PDT) (envelope-from owner-freebsd-multimedia@FreeBSD.ORG) Received: from relay8.uu.net (relay8.uu.net [192.48.96.84]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id JAA29330 for ; Tue, 28 Apr 1998 09:28:50 -0700 (PDT) (envelope-from jhall@UU.NET) Received: from neserve0.uu.net by relay8.uu.net with ESMTP (peer crosschecked as: neserve0.uu.net [153.39.50.135]) id QQenbt05226; Tue, 28 Apr 1998 12:28:31 -0400 (EDT) Received: by neserve0.uu.net id QQenbt29136; Tue, 28 Apr 1998 12:28:16 -0400 (EDT) From: jhall@UU.NET (Jeremy Hall) Message-Id: Subject: Re: multiple sdr -- found the problem To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Date: Tue, 28 Apr 1998 12:28:16 -0400 (EDT) Cc: MBONE@ISI.EDU, multimedia@FreeBSD.ORG In-Reply-To: <199804280637.IAA25958@labinfo.iet.unipi.it> from "Luigi Rizzo" at Apr 28, 98 08:37:08 am X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-multimedia@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I don't think two processes can own the same group/port combination. This is so the kernel knows where to send the packets. It is annoying if you're trying to run a transcoder. _J Luigi Rizzo said: > > It appears that there is a problem with running multiple instances of > SDR -- by different users -- on FreeBSD. It is not a problem in > sdr, but rather on bind(), and I wonder if it affects: > 1) other systems; > 2) other multicast applications. > > The problem (in sdr) is as follows: when two instances of sdr are > run by different users, the second one fails to bind to the same > port, unless it is root or has the same UID as the first one. > Haven't verified if the test is made on the UID, EUID, GID or > what. Nor I have verified if it is specific of FreeBSD or it also > occurs on other systems. > > I can see a reason for checking privileges on a bind -- if multiple > processes bind to the same port, some unprivileged process might > steal packet to another, more privileged one -- especially for > unicast traffic. > > For multicast, though, my belief is that there is intrinsically no > security in the use of this type of transport, so the check should be > relaxed. > > [in sdr, the offending bind() is called for INADDR_ANY ; i have tried > to set the address to a multicast group but it seems to make no > difference]. > > Comments/suggestions ? > > cheers > luigi > -----------------------------+-------------------------------------- > Luigi Rizzo | Dip. di Ingegneria dell'Informazione > email: luigi@iet.unipi.it | Universita' di Pisa > tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) > fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ > _____________________________|______________________________________ > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message