Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] tcp: md5: Fix overlap between vrf and non-vrf keys
To:     Leonard Crestez <cdleonard@gmail.com>,
        Eric Dumazet <edumazet@google.com>,
        David Ahern <dsahern@kernel.org>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Jakub Kicinski <kuba@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
        Yonghong Song <yhs@fb.com>,
        Alexander Duyck <alexanderduyck@fb.com>,
        Florian Westphal <fw@strlen.de>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <3d8387d499f053dba5cd9184c0f7b8445c4470c6.1633542093.git.cdleonard@gmail.com>
 <209548b5-27d2-2059-f2e9-2148f5a0291b@gmail.com>
 <912670a5-8ef2-79cc-b74b-ee5c83534f2b@gmail.com>
From:   David Ahern <dsahern@gmail.com>
Message-ID: <5c77ac1a-b6af-982f-d72f-e71098df3112@gmail.com>
Date:   Thu, 7 Oct 2021 12:27:41 -0600
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0)
 Gecko/20100101 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <912670a5-8ef2-79cc-b74b-ee5c83534f2b@gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 10/7/21 12:41 AM, Leonard Crestez wrote:
> 
> 
> On 07.10.2021 04:14, David Ahern wrote:
>> On 10/6/21 11:48 AM, Leonard Crestez wrote:
>>> @@ -1103,11 +1116,11 @@ static struct tcp_md5sig_key
>>> *tcp_md5_do_lookup_exact(const struct sock *sk,
>>>   #endif
>>>       hlist_for_each_entry_rcu(key, &md5sig->head, node,
>>>                    lockdep_sock_is_held(sk)) {
>>>           if (key->family != family)
>>>               continue;
>>> -        if (key->l3index && key->l3index != l3index)
>>> +        if (key->l3index != l3index)
>>
>> That seems like the bug fix there. The L3 reference needs to match for
>> new key and existing key. I think the same change is needed in
>> __tcp_md5_do_lookup.
> 
> Current behavior is that keys added without tcpm_ifindex will match
> connections both inside and outside VRFs. Changing this might break real
> applications, is it really OK to claim that this behavior was a bug all
> along?

no.

It's been a few years. I need to refresh on the logic and that is not
going to happen before this weekend.