From owner-freebsd-net@FreeBSD.ORG Sun May 16 07:17:03 2004 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 393BB16A4CE; Sun, 16 May 2004 07:17:03 -0700 (PDT) Received: from comp.chem.msu.su (comp.chem.msu.su [158.250.32.97]) by mx1.FreeBSD.org (Postfix) with ESMTP id 96E1843D53; Sun, 16 May 2004 07:17:01 -0700 (PDT) (envelope-from yar@comp.chem.msu.su) Received: from comp.chem.msu.su (localhost [127.0.0.1]) by comp.chem.msu.su (8.12.9p2/8.12.9) with ESMTP id i4GEGx3F040353; Sun, 16 May 2004 18:16:59 +0400 (MSD) (envelope-from yar@comp.chem.msu.su) Received: (from yar@localhost) by comp.chem.msu.su (8.12.9p2/8.12.9/Submit) id i4GEGwHc040352; Sun, 16 May 2004 18:16:59 +0400 (MSD) (envelope-from yar) Date: Sun, 16 May 2004 18:16:58 +0400 From: Yar Tikhiy To: arch@freebsd.org, net@freebsd.org Message-ID: <20040516141658.GA39893@comp.chem.msu.su> References: <20040508034514.GA937@grosbein.pp.ru> <20040508132354.GB44214@comp.chem.msu.su> <20040515182157.GB89625@comp.chem.msu.su> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040515182157.GB89625@comp.chem.msu.su> User-Agent: Mutt/1.5.6i cc: Eugene Grosbein Subject: TIME_WAIT sockets from other users (was Re: bin/65928: [PATCH] stock ftpd uses superuser credentials for active mode sockets) X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 May 2004 14:17:03 -0000 Note for the impatient: This message does not discuss the well-known issue of reusing local addresses through setting SO_REUSEADDR. This message is on reusing local addresses occupied by sockets belonging to other users. On Sat, May 15, 2004 at 10:21:57PM +0400, Yar Tikhiy wrote: > > Attached below is a patch addressing the issue of the inability to > reuse a local IP:port couple occupied by an established TCP connection > from another user, but by no listeners. Could anybody with fair > understanding of our TCP/IP stack review it please? Thanks. > > -- > Yar > > Index: in_pcb.c > =================================================================== > RCS file: /home/ncvs/src/sys/netinet/in_pcb.c,v > retrieving revision 1.146 > diff -u -p -r1.146 in_pcb.c > --- in_pcb.c 23 Apr 2004 23:29:49 -0000 1.146 > +++ in_pcb.c 15 May 2004 17:37:18 -0000 > @@ -340,6 +340,8 @@ in_pcbbind_setup(inp, nam, laddrp, lport > return (EADDRINUSE); > } else > if (t && > + (so->so_type != SOCK_STREAM || > + ntohl(t->inp_faddr.s_addr) == INADDR_ANY) && > (ntohl(sin->sin_addr.s_addr) != INADDR_ANY || > ntohl(t->inp_laddr.s_addr) != INADDR_ANY || > (t->inp_socket->so_options & One more detail to note: Currently if another user's socket is in the TIME_WAIT state, it still counts as occupying the local IP:port couple. I cannot see the point of such a behaviour. Restricting bind() is to disallow unprivileged port stealth, but how can one steal a connection in the TIME_WAIT state? For FreeBSD-4 the above patch would take care of this case along with established connections, but in CURRENT TIME_WAIT connections are a special case since they no longer use full-blown state. Therefore, for CURRENT the above patch mutates into the below one. Do I have a point? -- Yar Index: in_pcb.c =================================================================== RCS file: /home/ncvs/src/sys/netinet/in_pcb.c,v retrieving revision 1.146 diff -u -p -r1.146 in_pcb.c --- in_pcb.c 23 Apr 2004 23:29:49 -0000 1.146 +++ in_pcb.c 16 May 2004 13:33:33 -0000 @@ -332,14 +332,10 @@ in_pcbbind_setup(inp, nam, laddrp, lport * XXX * This entire block sorely needs a rewrite. */ - if (t && (t->inp_vflag & INP_TIMEWAIT)) { - if ((ntohl(sin->sin_addr.s_addr) != INADDR_ANY || - ntohl(t->inp_laddr.s_addr) != INADDR_ANY || - (intotw(t)->tw_so_options & SO_REUSEPORT) == 0) && - (so->so_cred->cr_uid != intotw(t)->tw_cred->cr_uid)) - return (EADDRINUSE); - } else if (t && + ((t->inp_vflag & INP_TIMEWAIT) == 0) && + (so->so_type != SOCK_STREAM || + ntohl(t->inp_faddr.s_addr) == INADDR_ANY) && (ntohl(sin->sin_addr.s_addr) != INADDR_ANY || ntohl(t->inp_laddr.s_addr) != INADDR_ANY || (t->inp_socket->so_options &