From: "Georg Kohmann (geokohma)" <geokohma@cisco.com>
To: Hangbin Liu <liuhangbin@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
"Jakub Kicinski" <kuba@kernel.org>,
Willem de Bruijn <willemb@google.com>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCHv4 net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers
Date: Mon, 26 Oct 2020 14:49:25 +0000 [thread overview]
Message-ID: <ec2d260d-2d83-772f-9430-fee0d9d21c59@cisco.com> (raw)
In-Reply-To: <20201026125519.GO2531@dhcp-12-153.nay.redhat.com>
On 26.10.2020 13:55, Hangbin Liu wrote:
> On Mon, Oct 26, 2020 at 08:09:21AM +0000, Georg Kohmann (geokohma) wrote:
>>> + nexthdr = hdr->nexthdr;
>>> + offset = ipv6_skip_exthdr(skb, skb_transport_offset(skb), &nexthdr, &frag_off);
>>> + if (offset < 0)
>>> + goto fail_hdr;
>>> +
>>> + /* Check some common protocols' header */
>>> + if (nexthdr == IPPROTO_TCP)
>>> + offset += sizeof(struct tcphdr);
>>> + else if (nexthdr == IPPROTO_UDP)
>>> + offset += sizeof(struct udphdr);
>>> + else if (nexthdr == IPPROTO_ICMPV6)
>>> + offset += sizeof(struct icmp6hdr);
>>> + else
>>> + offset += 1;
>> Maybe also check the special case IPPROTO_NONE?
> IPPROTO_NONE defines the same with NEXTHDR_NONE. So ipv6_skip_exthdr() will
> return -1, and we will goto fail_hdr and send ICMP parameter error message.
>
> The question is if it's OK to reply a ICMP error for fragment + IPPROTO_NONE
> packet? For pure IPPROTO_NONE message, we should drop silently, but what about
> fragment message?
According to RFC8200 section 4.7: "If the Payload Length field of the IPv6
header indicates the presence of octets past the end of a header whose
Next Header field contains 59, those octets must be ignored and passed
on unchanged if the packet is forwarded." I have not found any RFC
describing different behaviour for fragmented packets.
>
>>> +
>>> + if (frag_off == htons(IP6_MF) && offset > skb->len) {
>>> + __IP6_INC_STATS(net, __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INHDRERRORS);
>>> + icmpv6_param_prob(skb, ICMPV6_HDR_INCOMP, 0);
>>> + return -1;
>>> + }
>>> +
>>> iif = skb->dev ? skb->dev->ifindex : 0;
>>> fq = fq_find(net, fhdr->identification, hdr, iif);
>>> if (fq) {
>> Are you planning to also add this fix for the fragmentation handling in the netfilter?
>>
> I have no plan to fix this on netfilter as netfilter is a module.
> It may have different behavior during defragment.
>
> Thanks
> Hangbin
I might have a look at the netfilter myself then.
Thanks
Georg
next prev parent reply other threads:[~2020-10-26 14:49 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-07 3:55 [PATCH net 0/2] IPv6: reply ICMP error with fragment doesn't contain all headers Hangbin Liu
2020-10-07 3:55 ` [PATCH net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-07 3:55 ` [PATCH net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers Hangbin Liu
2020-10-07 9:35 ` Eric Dumazet
2020-10-08 8:30 ` Hangbin Liu
2020-10-08 9:47 ` Eric Dumazet
2020-10-09 10:07 ` Hangbin Liu
2020-10-07 14:58 ` Jakub Kicinski
2020-10-08 8:36 ` Hangbin Liu
2020-10-21 4:20 ` [PATCHv2 net 0/2] IPv6: reply ICMP error with fragment doesn't contain " Hangbin Liu
2020-10-21 4:20 ` [PATCHv2 net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-21 4:20 ` [PATCHv2 net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers Hangbin Liu
2020-10-21 14:02 ` Willem de Bruijn
2020-10-22 9:12 ` Hangbin Liu
2020-10-22 15:46 ` Willem de Bruijn
2020-10-23 6:43 ` [PATCHv3 net 0/2] IPv6: reply ICMP error if fragment doesn't contain " Hangbin Liu
2020-10-23 6:43 ` [PATCHv3 net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-23 6:43 ` [PATCHv3 net 2/2] IPv6: reply ICMP error if the first fragment doesn't include all headers Hangbin Liu
2020-10-23 18:18 ` Jakub Kicinski
2020-10-26 7:29 ` [PATCHv4 net 0/2] IPv6: reply ICMP error if fragment doesn't contain " Hangbin Liu
2020-10-26 7:29 ` [PATCHv4 net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-26 7:29 ` [PATCHv4 net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers Hangbin Liu
2020-10-26 8:09 ` Georg Kohmann (geokohma)
2020-10-26 12:55 ` Hangbin Liu
2020-10-26 14:49 ` Georg Kohmann (geokohma) [this message]
2020-10-27 2:28 ` [PATCHv5 net 0/2] IPv6: reply ICMP error if fragment doesn't contain " Hangbin Liu
2020-10-27 2:28 ` [PATCHv5 net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-27 2:28 ` [PATCHv5 net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers Hangbin Liu
2020-10-27 7:57 ` Georg Kohmann (geokohma)
2020-10-27 9:57 ` Hangbin Liu
2020-10-27 10:20 ` Georg Kohmann (geokohma)
2020-10-30 15:31 ` Willem de Bruijn
2020-10-30 18:39 ` Georg Kohmann (geokohma)
2020-10-27 12:33 ` [PATCHv6 net 0/2] IPv6: reply ICMP error if fragment doesn't contain " Hangbin Liu
2020-10-27 12:33 ` [PATCHv6 net 1/2] ICMPv6: Add ICMPv6 Parameter Problem, code 3 definition Hangbin Liu
2020-10-27 12:33 ` [PATCHv6 net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers Hangbin Liu
2020-10-31 21:12 ` [PATCHv6 net 0/2] IPv6: reply ICMP error if fragment doesn't contain " Jakub Kicinski
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