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 1D9393754FA; Mon, 5 May 2025 22:59:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746485969; cv=none; b=aVSqZM6sZR03jhxxQyvFwLse5OAy5MbkWtgpeR3Y9hwsPmq7xji1n4rmbfcIoqWpH76TL6Lq9ExUO10c3tKbrJy9FanaIotyCh/TkIBgT2pDZsRV2YH/mAnvn0/vJCbNe3WdA/d+/sD9cETGozZbr67m4MdvdNINxZinaX9m2HE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746485969; c=relaxed/simple; bh=enuVCNsbhg0ZB5FyH6LJC0qyUv/5ft3hKGEjWtDxo4U=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=KgyhD3uEid8OcfVOJM7uBhTYAtqljidLrhF0lS73tFHUAGRFiGAIWjPosSACgk7ddz0jMU0BRI6pxyzU8v48WsB36rbNlaV8bx0ZUyscGRqJPJowy7LGSGpLH7w0PzzNaSAU9kC5/IWzRcIQslvFpfCxQBsopC5qMlxBzbwr2Jc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LQA1Kf96; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LQA1Kf96" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DED0CC4CEED; Mon, 5 May 2025 22:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746485968; bh=enuVCNsbhg0ZB5FyH6LJC0qyUv/5ft3hKGEjWtDxo4U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LQA1Kf96OqN5Uv7A8SeEQSWoTHfkJMRdTp2VhKuGh2GzHev2o4pfz1/y4wJAAVs42 F7oV2jOw9by90JpgOb+2tHwR8c60TpUb22WpkKUVSaDXK8OsZcwpy2h+KjzQ9aeDIW GXA21lbPh2VCeaf4uEd2nb9J8Yyn882sEwCK2/J1Wq0FsEBy1VwnO+kYsKEUNUOe4G yvt5TdE+eKdp7GCbKPG5HxsaA0tuVWLAc7+XCibaXF6warcFydv3ZrGSo6ZPFGPOr7 d0nxD+IWMhWb4lM37RdbjUhpvssUukUKUYV519/MGQItaM3OwPzkHpQOEQ7IhHmbEP SXAO8F+13BZfQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Willem de Bruijn , Eric Dumazet , Jakub Kicinski , Sasha Levin , davem@davemloft.net, dsahern@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 092/294] ipv6: save dontfrag in cork Date: Mon, 5 May 2025 18:53:12 -0400 Message-Id: <20250505225634.2688578-92-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505225634.2688578-1-sashal@kernel.org> References: <20250505225634.2688578-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.89 Content-Transfer-Encoding: 8bit From: Willem de Bruijn [ Upstream commit a18dfa9925b9ef6107ea3aa5814ca3c704d34a8a ] When spanning datagram construction over multiple send calls using MSG_MORE, per datagram settings are configured on the first send. That is when ip(6)_setup_cork stores these settings for subsequent use in __ip(6)_append_data and others. The only flag that escaped this was dontfrag. As a result, a datagram could be constructed with df=0 on the first sendmsg, but df=1 on a next. Which is what cmsg_ip.sh does in an upcoming MSG_MORE test in the "diff" scenario. Changing datagram conditions in the middle of constructing an skb makes this already complex code path even more convoluted. It is here unintentional. Bring this flag in line with expected sockopt/cmsg behavior. And stop passing ipc6 to __ip6_append_data, to avoid such issues in the future. This is already the case for __ip_append_data. inet6_cork had a 6 byte hole, so the 1B flag has no impact. Signed-off-by: Willem de Bruijn Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250307033620.411611-3-willemdebruijn.kernel@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/linux/ipv6.h | 1 + net/ipv6/ip6_output.c | 9 +++++---- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index af8a771a053c5..d79851c5fabd8 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -199,6 +199,7 @@ struct inet6_cork { struct ipv6_txoptions *opt; u8 hop_limit; u8 tclass; + u8 dontfrag:1; }; /* struct ipv6_pinfo - ipv6 private area */ diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index cd89a2b35dfb5..b840021f79e98 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1452,6 +1452,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, } v6_cork->hop_limit = ipc6->hlimit; v6_cork->tclass = ipc6->tclass; + v6_cork->dontfrag = ipc6->dontfrag; if (rt->dst.flags & DST_XFRM_TUNNEL) mtu = np->pmtudisc >= IPV6_PMTUDISC_PROBE ? READ_ONCE(rt->dst.dev->mtu) : dst_mtu(&rt->dst); @@ -1485,7 +1486,7 @@ static int __ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), void *from, size_t length, int transhdrlen, - unsigned int flags, struct ipcm6_cookie *ipc6) + unsigned int flags) { struct sk_buff *skb, *skb_prev = NULL; struct inet_cork *cork = &cork_full->base; @@ -1541,7 +1542,7 @@ static int __ip6_append_data(struct sock *sk, if (headersize + transhdrlen > mtu) goto emsgsize; - if (cork->length + length > mtu - headersize && ipc6->dontfrag && + if (cork->length + length > mtu - headersize && v6_cork->dontfrag && (sk->sk_protocol == IPPROTO_UDP || sk->sk_protocol == IPPROTO_ICMPV6 || sk->sk_protocol == IPPROTO_RAW)) { @@ -1913,7 +1914,7 @@ int ip6_append_data(struct sock *sk, return __ip6_append_data(sk, &sk->sk_write_queue, &inet->cork, &np->cork, sk_page_frag(sk), getfrag, - from, length, transhdrlen, flags, ipc6); + from, length, transhdrlen, flags); } EXPORT_SYMBOL_GPL(ip6_append_data); @@ -2118,7 +2119,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk, err = __ip6_append_data(sk, &queue, cork, &v6_cork, ¤t->task_frag, getfrag, from, length + exthdrlen, transhdrlen + exthdrlen, - flags, ipc6); + flags); if (err) { __ip6_flush_pending_frames(sk, &queue, cork, &v6_cork); return ERR_PTR(err); -- 2.39.5