From: zhang kai <zhangkaiheb@126.com>
To: pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de,
davem@davemloft.net, kuba@kernel.org,
netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: zhang kai <zhangkaiheb@126.com>
Subject: [PATCH] netfilter: seqadj: check seq offset before update
Date: Fri, 24 Dec 2021 10:37:13 +0800 [thread overview]
Message-ID: <20211224023713.9260-1-zhangkaiheb@126.com> (raw)
if seq/ack offset is zero, don't update
Signed-off-by: zhang kai <zhangkaiheb@126.com>
---
net/netfilter/nf_conntrack_seqadj.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/net/netfilter/nf_conntrack_seqadj.c b/net/netfilter/nf_conntrack_seqadj.c
index 3066449f8bd8..d35e272a2e36 100644
--- a/net/netfilter/nf_conntrack_seqadj.c
+++ b/net/netfilter/nf_conntrack_seqadj.c
@@ -186,11 +186,13 @@ int nf_ct_seq_adjust(struct sk_buff *skb,
else
seqoff = this_way->offset_before;
- newseq = htonl(ntohl(tcph->seq) + seqoff);
- inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, false);
- pr_debug("Adjusting sequence number from %u->%u\n",
- ntohl(tcph->seq), ntohl(newseq));
- tcph->seq = newseq;
+ if (seqoff) {
+ newseq = htonl(ntohl(tcph->seq) + seqoff);
+ inet_proto_csum_replace4(&tcph->check, skb, tcph->seq, newseq, false);
+ pr_debug("Adjusting sequence number from %u->%u\n",
+ ntohl(tcph->seq), ntohl(newseq));
+ tcph->seq = newseq;
+ }
if (!tcph->ack)
goto out;
@@ -201,6 +203,9 @@ int nf_ct_seq_adjust(struct sk_buff *skb,
else
ackoff = other_way->offset_before;
+ if (!ackoff)
+ goto out;
+
newack = htonl(ntohl(tcph->ack_seq) - ackoff);
inet_proto_csum_replace4(&tcph->check, skb, tcph->ack_seq, newack,
false);
--
2.17.1
next reply other threads:[~2021-12-24 3:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-24 2:37 zhang kai [this message]
2022-01-06 21:53 ` Pablo Neira Ayuso
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