Date: Tue, 28 Apr 1998 08:37:08 +0200 (MET DST) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: MBONE@isi.edu, multimedia@FreeBSD.ORG Subject: multiple sdr -- found the problem Message-ID: <199804280637.IAA25958@labinfo.iet.unipi.it> In-Reply-To: <25298.892667239@north.lcs.mit.edu> from "Mark Handley" at Apr 15, 98 03:07:00 pm
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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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