netdev - Re: [PATCH v2 net-next 2/2] sit: add support of x-netns

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]

Message-Id: <20130625.224810.293452557691677283.davem@davemloft.net>
Date:	Tue, 25 Jun 2013 22:48:10 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	ebiederm@...ssion.com
Cc:	nicolas.dichtel@...nd.com, netdev@...r.kernel.org, bcrl@...ck.org,
	ravi.mlists@...il.com, bhutchings@...arflare.com
Subject: Re: [PATCH v2 net-next 2/2] sit: add support of x-netns

From: ebiederm@...ssion.com (Eric W. Biederman)
Date: Tue, 25 Jun 2013 18:35:30 -0700

> David Miller <davem@...emloft.net> writes:
> 
>> From: Nicolas Dichtel <nicolas.dichtel@...nd.com>
>> Date: Tue, 25 Jun 2013 16:24:55 +0200
>>
>>> @@ -453,6 +454,8 @@ int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
>>>  	tstats->rx_bytes += skb->len;
>>>  	u64_stats_update_end(&tstats->syncp);
>>>  
>>> +	skb_scrub_packet(skb);
>>> +
>>>  	if (tunnel->dev->type == ARPHRD_ETHER) {
>>>  		skb->protocol = eth_type_trans(skb, tunnel->dev);
>>>  		skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
>>
>> I can't see how this can be ok.
>>
>> If something in netfilter depends upon the state you are clearing out
>> here, someone's packet filtering setup is going to break.
>>
>> I'm not applying these patches, sorry.
> 
> How can netfilter depend on the state of a packet inside of a tunnel?
> 
> How can it even make sense?
> 
> Or is your concern that we unintentionally allowed this in the past so
> to avoid breaking binary compatibility we should continue in case
> someone somewhere cares?
> 
> I really can't see how this could possibly be an intentional feature.

You can make all of these issues go away by only clearing the SKB
meta state when namespaces are actually changing as we go through
the tunnel.
--
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