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 CF088226D1D; Mon, 2 Jun 2025 14:55:48 +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=1748876148; cv=none; b=IyJqUNYkSwViVsZE87JsoODU2yKMHSZokWCn/uk8F03VRAdOKMpCyTlzq3YQ7FPt0L1+PQDLQIXlbCmQM2p+XhSxVkUGTaumxMQZbMLRzUxvpc3E7/vMWzVZ8oLqZ7bGQSinU225hhLz/9E1VMaQ9BqP45chbaJaMfRF6XTTvlE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748876148; c=relaxed/simple; bh=sH1nSFdTKzFODSKSfkjwHOlu0yRPMF4SqGtyoY/kI/M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OeMYMVK/yyPrvNcVrw+oA7fmeUjMauwBzP4gbudgKgbW1r0qUgh7laLuRp5lyil/QJU7wASV9YEjvLyrDKn706MLb+jTYVsow/tY5LK8uqAH9vqlBJUL+o9rmyF6tVi9WdZLFtUlgC+GkqxtwfiykD4aGbBXTiU7varDqBzkPE4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qDmXXYgJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qDmXXYgJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56897C4CEEB; Mon, 2 Jun 2025 14:55:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1748876148; bh=sH1nSFdTKzFODSKSfkjwHOlu0yRPMF4SqGtyoY/kI/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qDmXXYgJ9gwoncy3QuiLbWoAtyRDKF4ng7w/SvMY0KwEuykKC3Rxy3qu1mn7PRa6G Pdz0OFqcL/cBWiBhLdl2opw4bnr0awWr+fI4v5hfeLCLai/91t0vfhMtilrcZcQ9zp M54c1acUHiENHE5pv83woSf0l3MS0TKUbvgifMKY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Willem de Bruijn , Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 056/207] ipv6: save dontfrag in cork Date: Mon, 2 Jun 2025 15:47:08 +0200 Message-ID: <20250602134300.946704384@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250602134258.769974467@linuxfoundation.org> References: <20250602134258.769974467@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ 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 b6fb76568b01a..5dfd663b70a26 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -195,6 +195,7 @@ struct inet6_cork { struct ipv6_txoptions *opt; u8 hop_limit; u8 tclass; + u8 dontfrag:1; }; /** diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4fcff4fe5a98f..a71b7a1069958 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1428,6 +1428,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork, cork->fl.u.ip6 = *fl6; 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); @@ -1462,7 +1463,7 @@ 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; unsigned int maxfraglen, fragheaderlen, mtu, orig_mtu, pmtu; @@ -1519,7 +1520,7 @@ 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_RAW)) { ipv6_local_rxpmtu(sk, fl6, mtu - headersize + @@ -1836,7 +1837,7 @@ int ip6_append_data(struct sock *sk, return __ip6_append_data(sk, fl6, &sk->sk_write_queue, &inet->cork.base, &np->cork, sk_page_frag(sk), getfrag, - from, length, transhdrlen, flags, ipc6); + from, length, transhdrlen, flags); } EXPORT_SYMBOL_GPL(ip6_append_data); @@ -2031,7 +2032,7 @@ struct sk_buff *ip6_make_skb(struct sock *sk, err = __ip6_append_data(sk, fl6, &queue, &cork->base, &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