netdev - [PATCH net-next v3] tcp: remove unnecessary update for tp->write_seq in tcp

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1728289544-4611-1-git-send-email-guoxin0309@gmail.com>
Date: Mon,  7 Oct 2024 16:25:44 +0800
From: "xin.guo" <guoxin0309@...il.com>
To: edumazet@...gle.com,
	ncardwell@...gle.com
Cc: netdev@...r.kernel.org,
	"xin.guo" <guoxin0309@...il.com>
Subject: [PATCH net-next v3] tcp: remove unnecessary update for tp->write_seq in tcp_connect()

From: "xin.guo" <guoxin0309@...il.com>

Commit 783237e8daf13 ("net-tcp: Fast Open client - sending SYN-data")
introduces tcp_connect_queue_skb() and it would overwrite tcp->write_seq,
so it is no need to update tp->write_seq before invoking
tcp_connect_queue_skb().

Signed-off-by: xin.guo <guoxin0309@...il.com>
---
v3: Fix the style issue.
v2: Add comment to explain when to update write_seq.
---
 net/ipv4/tcp_output.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 4fd746b..ab4e03a 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -4134,7 +4134,10 @@ int tcp_connect(struct sock *sk)
 	if (unlikely(!buff))
 		return -ENOBUFS;
 
-	tcp_init_nondata_skb(buff, tp->write_seq++, TCPHDR_SYN);
+	/* SYN eats a sequence byte, write_seq updated by
+	 * tcp_connect_queue_skb().
+	 */
+	tcp_init_nondata_skb(buff, tp->write_seq, TCPHDR_SYN);
 	tcp_mstamp_refresh(tp);
 	tp->retrans_stamp = tcp_time_stamp_ts(tp);
 	tcp_connect_queue_skb(sk, buff);
-- 
1.8.3.1