netdev - Re: [patch 1/1][NETNS][IPV6] protect addrconf from loopback registration

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:	Mon, 12 Nov 2007 09:51:58 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	"Denis V. Lunev" <den@...ru>
Cc:	Daniel Lezcano <dlezcano@...ibm.com>, davem@...emloft.net,
	netdev@...r.kernel.org, xemul@...nvz.org,
	containers@...ts.osdl.org, yoshfuji@...ux-ipv6.org,
	Benjamin Thery <benjamin.thery@...l.net>
Subject: Re: [patch 1/1][NETNS][IPV6] protect addrconf from loopback registration

"Denis V. Lunev" <den@...ru> writes:

>> Index: linux-2.6-netns/net/ipv6/addrconf.c
>> ===================================================================
>> --- linux-2.6-netns.orig/net/ipv6/addrconf.c
>> +++ linux-2.6-netns/net/ipv6/addrconf.c
>> @@ -2272,7 +2272,8 @@ static int addrconf_notify(struct notifi
>>  
>>  	switch(event) {
>>  	case NETDEV_REGISTER:
>> -		if (!idev && dev->mtu >= IPV6_MIN_MTU) {
>> +		if (!(dev->flags & IFF_LOOPBACK) &&
>> +		    !idev && dev->mtu >= IPV6_MIN_MTU) {

It is idev being true here for the loopback device that would
prevent things not missing the REGISTER event.

Hmm.  But we do call ipv6_add_dev on loopback and now the loopback
device is practically guaranteed to be the first device so we can
probably just remove the special case in addrconf_init.

Anyway Daniels patch makes increasingly less sense the more I look
at it.


> Namespaces are good to catch leakage using standard codepaths, so they
> should be preserved as much as possible. So, _all_ normal down code
> should be called for a loopback device in other than init_net context.

In any context. After the code path is aware of multiple network namespaces
init_net should not be special in any way.

I completely agree about the ability to catch weird leakage scenarios.

Eric
-
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