Messages in this thread | | | Date | Wed, 22 Jun 2022 20:19:08 +0200 | From | Ilya Maximets <> | Subject | Re: [PATCH net] net: ensure all external references are released in deferred skbuffs |
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On 6/22/22 19:03, Eric Dumazet wrote: > On Wed, Jun 22, 2022 at 6:47 PM Eric Dumazet <edumazet@google.com> wrote: >> >> On Wed, Jun 22, 2022 at 6:39 PM Eric Dumazet <edumazet@google.com> wrote: >>> >>> On Wed, Jun 22, 2022 at 6:29 PM Eric Dumazet <edumazet@google.com> wrote: >>>> >>>> On Wed, Jun 22, 2022 at 4:26 PM Ilya Maximets <i.maximets@ovn.org> wrote: >>>>> >>>>> On 6/22/22 13:43, Eric Dumazet wrote: >>>> >>>>> >>>>> I tested the patch below and it seems to fix the issue seen >>>>> with OVS testsuite. Though it's not obvious for me why this >>>>> happens. Can you explain a bit more? >>>> >>>> Anyway, I am not sure we can call nf_reset_ct(skb) that early. >>>> >>>> git log seems to say that xfrm check needs to be done before >>>> nf_reset_ct(skb), I have no idea why. >>> >>> Additional remark: In IPv6 side, xfrm6_policy_check() _is_ called >>> after nf_reset_ct(skb) >>> >>> Steffen, do you have some comments ? >>> >>> Some context: >>> commit b59c270104f03960069596722fea70340579244d >>> Author: Patrick McHardy <kaber@trash.net> >>> Date: Fri Jan 6 23:06:10 2006 -0800 >>> >>> [NETFILTER]: Keep conntrack reference until IPsec policy checks are done >>> >>> Keep the conntrack reference until policy checks have been performed for >>> IPsec NAT support. The reference needs to be dropped before a packet is >>> queued to avoid having the conntrack module unloadable. >>> >>> Signed-off-by: Patrick McHardy <kaber@trash.net> >>> Signed-off-by: David S. Miller <davem@davemloft.net> >>> >> >> Oh well... __xfrm_policy_check() has : >> >> nf_nat_decode_session(skb, &fl, family); >> >> This answers my questions. >> >> This means we are probably missing at least one XFRM check in TCP >> stack in some cases. >> (Only after adding this XFRM check we can call nf_reset_ct(skb)) >> > > Maybe this will help ?
I tested this patch and it seems to fix the OVS problem. I did not test the xfrm part of it.
Will you post an official patch?
> > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index fe8f23b95d32ca4a35d05166d471327bc608fa91..49c1348e40b6c7b6a98b54d716f29c948e00ba33 > 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -2019,12 +2019,19 @@ int tcp_v4_rcv(struct sk_buff *skb) > if (nsk == sk) { > reqsk_put(req); > tcp_v4_restore_cb(skb); > - } else if (tcp_child_process(sk, nsk, skb)) { > - tcp_v4_send_reset(nsk, skb); > - goto discard_and_relse; > } else { > - sock_put(sk); > - return 0; > + if (!xfrm4_policy_check(nsk, XFRM_POLICY_IN, skb)) { > + drop_reason = SKB_DROP_REASON_XFRM_POLICY; > + goto discard_and_relse; > + } > + nf_reset_ct(skb); > + if (tcp_child_process(sk, nsk, skb)) { > + tcp_v4_send_reset(nsk, skb); > + goto discard_and_relse; > + } else { > + sock_put(sk); > + return 0; > + } > } > }
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