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 3F4F3301000; Tue, 6 Jan 2026 17:43:17 +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=1767721398; cv=none; b=XItABodGFkJizkJdneeqR23PkA3ODg2Fvp1nk4MXL/Smjjm2o77zC8FXYB7ZbTilArxAbwEwM+TyqGaWBRp/Gf6rwoZoNHXC7i8LFqVffClHa0zWavQU6nUX9Qi44sasw/KBQclwfhDsi0vn3xFCSW/6E0T8NqZ3mcvspu51QEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767721398; c=relaxed/simple; bh=nwOAH8UHUkKR7dT7952/NaCp5/efTm95jbxlRdk8Rdk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RWoR2KJa5WjQafnIGu+a6iXySs1TVgZawedokNpFD3YYkmM7YPQx/q2s7GxE9e7VXF/rccjTMwklEenJk0/f/aiJT24qTXGg8SLFjNvWvMw1eRjscQammHHWO3Mcc/bpgHk8cj5tFhApyDyjnTQ0fzdgAyKnXxQbcSO/FlyVg8c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iS/4T2cL; 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="iS/4T2cL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51D7DC116C6; Tue, 6 Jan 2026 17:43:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767721397; bh=nwOAH8UHUkKR7dT7952/NaCp5/efTm95jbxlRdk8Rdk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iS/4T2cLsCxdB/fhycPLPMA/5p5aeaBSNa6V20m89LsMNaXmPJVCxwggpOVeOsrrI H7cMG1zkAVNxgAkKYzeGOXZ49PuYtT99o+6ycvfULA3JXhjnUE3QQThpwm8sVZL9n6 6EbiXmeTbmKUVXPYwbmu01MwticeFl1hCOxcKPww= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Andrii Melnychenko , Florian Westphal , Harshit Mogalapalli Subject: [PATCH 6.12 523/567] netfilter: nft_ct: add seqadj extension for natted connections Date: Tue, 6 Jan 2026 18:05:05 +0100 Message-ID: <20260106170510.736726106@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260106170451.332875001@linuxfoundation.org> References: <20260106170451.332875001@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andrii Melnychenko [ Upstream commit 90918e3b6404c2a37837b8f11692471b4c512de2 ] Sequence adjustment may be required for FTP traffic with PASV/EPSV modes. due to need to re-write packet payload (IP, port) on the ftp control connection. This can require changes to the TCP length and expected seq / ack_seq. The easiest way to reproduce this issue is with PASV mode. Example ruleset: table inet ftp_nat { ct helper ftp_helper { type "ftp" protocol tcp l3proto inet } chain prerouting { type filter hook prerouting priority 0; policy accept; tcp dport 21 ct state new ct helper set "ftp_helper" } } table ip nat { chain prerouting { type nat hook prerouting priority -100; policy accept; tcp dport 21 dnat ip prefix to ip daddr map { 192.168.100.1 : 192.168.13.2/32 } } chain postrouting { type nat hook postrouting priority 100 ; policy accept; tcp sport 21 snat ip prefix to ip saddr map { 192.168.13.2 : 192.168.100.1/32 } } } Note that the ftp helper gets assigned *after* the dnat setup. The inverse (nat after helper assign) is handled by an existing check in nf_nat_setup_info() and will not show the problem. Topoloy: +-------------------+ +----------------------------------+ | FTP: 192.168.13.2 | <-> | NAT: 192.168.13.3, 192.168.100.1 | +-------------------+ +----------------------------------+ | +-----------------------+ | Client: 192.168.100.2 | +-----------------------+ ftp nat changes do not work as expected in this case: Connected to 192.168.100.1. [..] ftp> epsv EPSV/EPRT on IPv4 off. ftp> ls 227 Entering passive mode (192,168,100,1,209,129). 421 Service not available, remote server has closed connection. Kernel logs: Missing nfct_seqadj_ext_add() setup call WARNING: CPU: 1 PID: 0 at net/netfilter/nf_conntrack_seqadj.c:41 [..] __nf_nat_mangle_tcp_packet+0x100/0x160 [nf_nat] nf_nat_ftp+0x142/0x280 [nf_nat_ftp] help+0x4d1/0x880 [nf_conntrack_ftp] nf_confirm+0x122/0x2e0 [nf_conntrack] nf_hook_slow+0x3c/0xb0 .. Fix this by adding the required extension when a conntrack helper is assigned to a connection that has a nat binding. Fixes: 1a64edf54f55 ("netfilter: nft_ct: add helper set support") Signed-off-by: Andrii Melnychenko Signed-off-by: Florian Westphal [Harshit: Clean cherry-pick, apply it to stable-6.12.y] Signed-off-by: Harshit Mogalapalli Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nft_ct.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -22,6 +22,7 @@ #include #include #include +#include struct nft_ct_helper_obj { struct nf_conntrack_helper *helper4; @@ -1173,6 +1174,10 @@ static void nft_ct_helper_obj_eval(struc if (help) { rcu_assign_pointer(help->helper, to_assign); set_bit(IPS_HELPER_BIT, &ct->status); + + if ((ct->status & IPS_NAT_MASK) && !nfct_seqadj(ct)) + if (!nfct_seqadj_ext_add(ct)) + regs->verdict.code = NF_DROP; } }