netdev - Re: [PATCH] ipv6: don't call addrconf_dst

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 2 Jan 2014 07:54:29 +0100
From:	Hannes Frederic Sowa <hannes@...essinduktion.org>
To:	chenweilong <chenweilong@...wei.com>
Cc:	David Miller <davem@...emloft.net>, gaofeng@...fujitsu.com,
	kumaran.4353@...il.com, netdev@...r.kernel.org
Subject: Re: [PATCH] ipv6: don't call addrconf_dst_alloc again when enable lo

On Thu, Jan 02, 2014 at 01:48:46PM +0800, chenweilong wrote:
> On 2013/12/31 11:57, Hannes Frederic Sowa wrote:
> > On Wed, Jun 19, 2013 at 11:05:32PM -0700, David Miller wrote:
> >> From: Gao feng <gaofeng@...fujitsu.com>
> >> Date: Sun, 16 Jun 2013 11:14:30 +0800
> >>
> >>> If we disable all of the net interfaces, and enable
> >>> un-lo interface before lo interface, we already allocated
> >>> the addrconf dst in ipv6_add_addr. So we shouldn't allocate
> >>> it again when we enable lo interface.
> >>>
> >>> Otherwise the message below will be triggered.
> >>> unregister_netdevice: waiting for sit1 to become free. Usage count = 1
> >>>
> >>> This problem is introduced by commit 25fb6ca4ed9cad72f14f61629b68dc03c0d9713f
> >>> "net IPv6 : Fix broken IPv6 routing table after loopback down-up"
> >>>
> >>> Signed-off-by: Gao feng <gaofeng@...fujitsu.com>
> >>
> >> This is the second such regression added by that commit :-/
> >>
> >> Applied and queue up for -stable, thanks.
> > 
> > Hmm, and this change also has a regression and breaks the original fix. :/
> > 
> > https://bugzilla.kernel.org/show_bug.cgi?id=67951
> > 
> > I tried to track it down but it seems pretty complicated. Maybe we have to
> > special-case the take-down of the loopback device.
> > 
> > 
> > 
> 
> When I did the tests,If 'ifconfig lo down',all IPv6 connection broken,
> but IPv4 connection were still OK.
> 
> Is it designed like that or a bug?

This seems to solve the loopback up/down problem, but there are still
some issues with up/down of interfaces and routing table interactions.

We enable routes over interfaces when interface is actually down and
kick manually specified on-link routes when we actually should try to
keep them and just disable them.

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6c16345..61d752a 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2629,8 +2629,10 @@ static void init_loopback(struct net_device *dev)
 			if (sp_ifa->flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE))
 				continue;
 
-			if (sp_ifa->rt)
+			if (sp_ifa->rt) {
+				ip6_ins_rt(sp_ifa->rt);
 				continue;
+			}
 
 			sp_rt = addrconf_dst_alloc(idev, &sp_ifa->addr, false);
 
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html