netdev - Re: [PATCH v2] ip6tnl: do route updating for redirect in ip6_tnl

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 for Android: free password hash cracker in your pocket

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

Message-Id: <20130919.140213.417316271045370155.davem@davemloft.net>
Date:	Thu, 19 Sep 2013 14:02:13 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	djduanjiong@...il.com
Cc:	netdev@...r.kernel.org, duanj.fnst@...fujitsu.com
Subject: Re: [PATCH v2] ip6tnl: do route updating for redirect in
 ip6_tnl_err()

From: Duan Jiong <djduanjiong@...il.com>
Date: Tue, 17 Sep 2013 20:27:57 -0700

> After the ip6_tnl_err() is called, the rel_msg is assigned to
> 0, and the ip4ip6_err() will return directly, the instruction
> below will not be executed.
> 
> In rfc2473, we can know that the tunnel ICMP redirect message
> should not be reported to the source of the original packet,
> so we can handle it in ip6_tnl_err().
> 
> Signed-off-by: Duan Jiong <duanj.fnst@...fujitsu.com>

I do not think this change is correct.

> @@ -576,9 +579,6 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
>  		rel_type = ICMP_DEST_UNREACH;
>  		rel_code = ICMP_FRAG_NEEDED;
>  		break;
> -	case NDISC_REDIRECT:
> -		rel_type = ICMP_REDIRECT;
> -		rel_code = ICMP_REDIR_HOST;
>  	default:
>  		return 0;
>  	}

The bug is a missing "break;" statement for this case, and:

> @@ -637,8 +637,6 @@ ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
>  
>  		skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
>  	}
> -	if (rel_type == ICMP_REDIRECT)
> -		skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
>  

We absolutely must run the ipv4 dst_ops redirect handler here so you must
keep this code around as well.

The only change you need to make is to add the missing break;
statement to ip4ip6_err() and then also add appropriate NDISC_REDIRECT
handling to ip6ip6_err().
--
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