From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC4DCFC08 for ; Mon, 15 May 2023 17:17:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 381F8C433EF; Mon, 15 May 2023 17:17:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684171024; bh=H1FWlXP83lMIzC6FlGmja1MxJ6GgUcXSQL9G4k2Axs0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EcZ1Rl3ERrP3twqYktGDCEsXrk5JeoAtZGY8JL0NtW0Wo52gUbDUONRcD/qXJO0mZ SLu7DVVVR2yK+/qaGFAEU3FL7kv1imW5XXBhGGqgVu/lI6JNV1EeCEMJLehXx0TLNK 1ch5aPBnnMdoYVjymyi1HkRpyTYtLJaObvIPnIWA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Antoine Tenart , Eric Dumazet , "David S. Miller" , Sasha Levin Subject: [PATCH 6.2 047/242] net: ipv6: fix skb hash for some RST packets Date: Mon, 15 May 2023 18:26:13 +0200 Message-Id: <20230515161723.327672864@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161721.802179972@linuxfoundation.org> References: <20230515161721.802179972@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Antoine Tenart [ Upstream commit dc6456e938e938d64ffb6383a286b2ac9790a37f ] The skb hash comes from sk->sk_txhash when using TCP, except for some IPv6 RST packets. This is because in tcp_v6_send_reset when not in TIME_WAIT the hash is taken from sk->sk_hash, while it should come from sk->sk_txhash as those two hashes are not computed the same way. Packetdrill script to test the above, 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 +0 connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress) +0 > (flowlabel 0x1) S 0:0(0) <...> // Wrong ack seq, trigger a rst. +0 < S. 0:0(0) ack 0 win 4000 // Check the flowlabel matches prior one from SYN. +0 > (flowlabel 0x1) R 0:0(0) <...> Fixes: 9258b8b1be2e ("ipv6: tcp: send consistent autoflowlabel in RST packets") Signed-off-by: Antoine Tenart Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/ipv6/tcp_ipv6.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index e4da7267ed4bd..e0706c33e5472 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1064,7 +1064,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) if (np->repflow) label = ip6_flowlabel(ipv6h); priority = sk->sk_priority; - txhash = sk->sk_hash; + txhash = sk->sk_txhash; } if (sk->sk_state == TCP_TIME_WAIT) { label = cpu_to_be32(inet_twsk(sk)->tw_flowlabel); -- 2.39.2