Messages in this thread | | | Subject | Re: [PATCH] tcp: md5: Fix overlap between vrf and non-vrf keys | From | Leonard Crestez <> | Date | Thu, 7 Oct 2021 09:41:42 +0300 |
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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?
The approach with most backward compatibility would be to add a new flag for keys that only match non-vrf connections.
Alternatively (TCP_MD5SIG_FLAG_IFINDEX && tcpm_ifindex == 0) could be defined as "only non-vrf connections" while TCP_MD5SIG_FLAG_IFINDEX missing could be "either".
-- Regards, Leonard
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