Date: Tue, 28 Apr 1998 12:28:16 -0400 (EDT) From: jhall@UU.NET (Jeremy Hall) To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: MBONE@ISI.EDU, multimedia@FreeBSD.ORG Subject: Re: multiple sdr -- found the problem Message-ID: <QQenbt29136.199804281628@neserve0.uu.net> In-Reply-To: <199804280637.IAA25958@labinfo.iet.unipi.it> from "Luigi Rizzo" at Apr 28, 98 08:37:08 am
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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
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