netdev - [PATCH 3/7] netfilter: Drop fragmented ndisc packets assembled in netfilter

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Message-Id: <20201022172925.22770-4-pablo@netfilter.org>
Date:   Thu, 22 Oct 2020 19:29:21 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org
Subject: [PATCH 3/7] netfilter: Drop fragmented ndisc packets assembled in netfilter

From: Georg Kohmann <geokohma@...co.com>

Fragmented ndisc packets assembled in netfilter not dropped as specified
in RFC 6980, section 5. This behaviour breaks TAHI IPv6 Core Conformance
Tests v6LC.2.1.22/23, V6LC.2.2.26/27 and V6LC.2.3.18.

Setting IP6SKB_FRAGMENTED flag during reassembly.

References: commit b800c3b966bc ("ipv6: drop fragmented ndisc packets by default (RFC 6980)")
Signed-off-by: Georg Kohmann <geokohma@...co.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/ipv6/netfilter/nf_conntrack_reasm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index fed9666a2f7d..054d287eb13d 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -355,6 +355,7 @@ static int nf_ct_frag6_reasm(struct frag_queue *fq, struct sk_buff *skb,
 	ipv6_hdr(skb)->payload_len = htons(payload_len);
 	ipv6_change_dsfield(ipv6_hdr(skb), 0xff, ecn);
 	IP6CB(skb)->frag_max_size = sizeof(struct ipv6hdr) + fq->q.max_size;
+	IP6CB(skb)->flags |= IP6SKB_FRAGMENTED;
 
 	/* Yes, and fold redundant checksum back. 8) */
 	if (skb->ip_summed == CHECKSUM_COMPLETE)
-- 
2.20.1