From: kuznet@ms2.inr.ac.ru
Message-Id: <200208081836.WAA03110@sex.inr.ac.ru>
Subject: Re: Unix-domain sockets - abstract addresses
To: lkml@procter-collective.ORG.UK (Michael Procter)
Date: Thu, 8 Aug 2002 22:36:38 +0400 (MSD)
Cc: linux-kernel@vger.kernel.org
In-Reply-To: <20020808171524.A2469@cad.citel.com> from "Michael Procter" at Aug 8, 2 08:45:01 pm
MIME-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1235
Lines: 39

Hello!

> According to the man page 'unix(7)':
> When a socket is connected and it doesn't already have a local address a
> unique address in the abstract namespace will be generated automatically.

This is wrong. The address is not autogenerated unless SO_PASSCRED
is requested by security&compatibility reasons.
So, if the socket is SOCK_DGRAM it is anounymous and "send-only",
it is impossible to reply to it.


> but I have seen 0x0BA5, 0x7FA8, 0x1FA8 and others).

Yes, this is bug. The fix is enclosed. It should return nil address.

> So, the question is:  which is right?  The man page, or af_unix.c?

Both of them are wrong.

Alexey


--- af_unix.c.orig	Thu Aug  8 22:23:56 2002
+++ af_unix.c	Thu Aug  8 22:34:58 2002
@@ -1432,7 +1432,7 @@
 
 static void unix_copy_addr(struct msghdr *msg, struct sock *sk)
 {
-	msg->msg_namelen = sizeof(short);
+	msg->msg_namelen = 0;
 	if (sk->protinfo.af_unix.addr) {
 		msg->msg_namelen=sk->protinfo.af_unix.addr->len;
 		memcpy(msg->msg_name,
-
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