netdev - Re: [PATCH net] seg6: fix route leak for encap routes

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: <3394763c-c546-4c80-8157-98467c8e8698@redhat.com>
Date: Thu, 18 Dec 2025 11:35:43 +0100
From: Paolo Abeni <pabeni@...hat.com>
To: Andrea Mayer <andrea.mayer@...roma2.it>, nicolas.dichtel@...nd.com
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski
 <kuba@...nel.org>, Eric Dumazet <edumazet@...gle.com>,
 David Lebrun <david.lebrun@...ouvain.be>,
 Paolo Lungaroni <paolo.lungaroni@...roma2.it>,
 David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org,
 stefano.salsano@...roma2.it
Subject: Re: [PATCH net] seg6: fix route leak for encap routes

On 12/14/25 2:39 PM, Andrea Mayer wrote:
> On Wed, 10 Dec 2025 18:00:39 +0100
> Nicolas Dichtel <nicolas.dichtel@...nd.com> wrote:
>> Le 10/12/2025 à 11:37, Andrea Mayer a écrit :
>>> I've got your point. However, I'm still concerned about the implications of
>>> using the *dev* field in the root lookup. This field has been ignored for this
>>> purpose so far, so some existing configurations/scripts may need to be adapted
>>> to work again. The adjustments made to the self-tests below show what might
>>> happen.
>> Yes, I was wondering how users use this *dev* arg. Maybe adding a new attribute,
>> something like SEG6_IPTUNNEL_USE_NH_DEV will avoid any regressions.
>>
> 
> IMHO using a new attribute seems to be a safer approach.

Given the functional implication I suggest using a new attribute. Given
that I also suggest targeting net-next for the next revision of this patch.

>>>> diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
>>>> index 3e1b9991131a..9535aea28357 100644
>>>> --- a/net/ipv6/seg6_iptunnel.c
>>>> +++ b/net/ipv6/seg6_iptunnel.c
>>>> @@ -484,6 +484,12 @@ static int seg6_input_core(struct net *net, struct sock *sk,
>>>>  	 * now and use it later as a comparison.
>>>>  	 */
>>>>  	lwtst = orig_dst->lwtstate;
>>>> +	if (orig_dst->dev) {

Here you should probably use dst_dev_rcu(), under the rcu lock, avoiding
touching dev twice.

/P