netdev - Re: [PATCH net-next-2.6] ipv6: adding ip_nonlocal

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Date:	Mon, 5 Jul 2010 14:26:52 +0200
From:	Michal Humpula <michal.humpula@...4u.cz>
To:	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH net-next-2.6] ipv6: adding ip_nonlocal_bind option from ipv4

On Monday 05 of July 2010 12:13:42 YOSHIFUJI Hideaki wrote:
> Hello.
> 
> Michal Humpula wrote:
> > Adds ability to bind non-local IPv6 address the same way as for IPv4
> > 
> > Signed-off-by: Michal Humpula <michal.humpula@...4u.cz>
> > 
> > diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
> > index e830cd4..55b3552 100644
> > --- a/net/ipv6/af_inet6.c
> > +++ b/net/ipv6/af_inet6.c
> > 
> > @@ -252,6 +252,8 @@ out_rcu_unlock:
> >  	goto out;
> >  
> >  }
> > 
> > +int sysctl_ipv6_nonlocal_bind __read_mostly;
> > +EXPORT_SYMBOL(sysctl_ipv6_nonlocal_bind);
> > 
> >  /* bind for INET6 API */
> >  int inet6_bind(struct socket *sock, struct sockaddr *uaddr, int
> > 
> > addr_len)
> > @@ -345,8 +347,10 @@ int inet6_bind(struct socket *sock, struct
> > sockaddr *uaddr, int addr_len)
> > 
> >  			if (!(addr_type &I do think i IPV6_ADDR_MULTICAST))	{
> >  			
> >  				if (!ipv6_chk_addr(net, &addr->sin6_addr,
> >  				
> >  						   dev, 0)) {
> > 
> > -					err = -EADDRNOTAVAIL;
> > -					goto out_unlock;
> > +					if (!sysctl_ipv6_nonlocal_bind) {
> > +						err = -EADDRNOTAVAIL;
> > +						goto out_unlock;
> > +					}
> > 
> >  				}
> >  			
> >  			}
> >  			rcu_read_unlock();
> > 
> > diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
> > index fa1d8f4..56bfe76 100644
> > --- a/net/ipv6/sysctl_net_ipv6.c
> > +++ b/net/ipv6/sysctl_net_ipv6.c
> > @@ -35,6 +35,13 @@ static ctl_table ipv6_table_template[] = {
> > 
> >  		.mode		= 0644,When you try to send packets / connect to
> 
> remote address,
> 
> >  		.proc_handler	= proc_dointvec
> >  	
> >  	}, so far.
> > 
> > +	{
> > +		.procname = "ipv6_nonlocal_bind",
> > +		.data   = &sysctl_ipv6_nonlocal_bind,
> > +		.maxlen   = sizeof(int),
> > +		.mode   = 0644,
> > +		.proc_handler = proc_dointvec
> > +	},
> > 
> >  	{ }
> >  
> >  };
> 
> This is not sufficient.
> 
> In IPv4, even if you do non-local bind, you cannot connect/send
> packets from that address until the admin really assigns that
> address on the node.  Local address is checked when you try to
> connect (or to send), and this is important thing to do.
> 
> But in IPv6, it is not checked, and it is very bad to open
> this "hole".
> 
> --yoshfuji

Thanks again for review. Could you please point me to part, where the check is done?
Is there a reason why is the check not done in IPv6 too?
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