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 D42F31CDFAC; Sun, 7 Sep 2025 20:10:31 +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=1757275831; cv=none; b=IPISQ4KEmK4zexirYfI/d6M6rwlTD/h4LS6SLO92VoZho3FtV4jliVtNQEVGi8Tf4yfWNZqAacnbZPr5tyy640mWvRYP2nbkv4hIyvkKraZoPMPpKOoxUWb1Dj/ppd93+1iO1dWD8pQTah44FsU5H4sRIGwbKfg0ZS/vAS00gYk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757275831; c=relaxed/simple; bh=oy5mU6bgilJuO4W+851rflwwdG1om6kecLPG5v/3yj8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=j8DfNMPaiNM4eWTrqq2h9vdRAXyM4A6wVPan8vlJmDU99nzFwyASyTkkW96CKoaysBsBrs5yrjRKhhC0VB2jdWnq7YH4nzCj+jtIK7jcnOnX9EkGfv8RKz7uLVfq15226qXPTW8g7IwCG5APMeTesXzpO47YsCW4bv86Zp521RE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=af/LKZZC; 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="af/LKZZC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59976C4CEF0; Sun, 7 Sep 2025 20:10:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1757275831; bh=oy5mU6bgilJuO4W+851rflwwdG1om6kecLPG5v/3yj8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=af/LKZZCDfBhTVcBQ0GjAo9q/dQ8x0XzkxjK7Nm0kMz1bC/Y1pCvZSyeZB9bChzwU y41PPmROSr2NULc7ISAx/lRbjF38PdIB+7UoiSYvuRHIpp5S3lU+jeR5k4E23r0HxY GPWiHIndZQTDrK55XygJ1uD/9bGpt3BORosgbbic= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Fabian=20Bl=C3=A4se?= , "Jason A. Donenfeld" , Florian Westphal , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 07/45] icmp: fix icmp_ndo_send address translation for reply direction Date: Sun, 7 Sep 2025 21:57:53 +0200 Message-ID: <20250907195601.177867484@linuxfoundation.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250907195600.953058118@linuxfoundation.org> References: <20250907195600.953058118@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore 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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fabian Bläse [ Upstream commit c6dd1aa2cbb72b33e0569f3e71d95792beab5042 ] The icmp_ndo_send function was originally introduced to ensure proper rate limiting when icmp_send is called by a network device driver, where the packet's source address may have already been transformed by SNAT. However, the original implementation only considers the IP_CT_DIR_ORIGINAL direction for SNAT and always replaced the packet's source address with that of the original-direction tuple. This causes two problems: 1. For SNAT: Reply-direction packets were incorrectly translated using the source address of the CT original direction, even though no translation is required. 2. For DNAT: Reply-direction packets were not handled at all. In DNAT, the original direction's destination is translated. Therefore, in the reply direction the source address must be set to the reply-direction source, so rate limiting works as intended. Fix this by using the connection direction to select the correct tuple for source address translation, and adjust the pre-checks to handle reply-direction packets in case of DNAT. Additionally, wrap the `ct->status` access in READ_ONCE(). This avoids possible KCSAN reports about concurrent updates to `ct->status`. Fixes: 0b41713b6066 ("icmp: introduce helper for nat'd source address in network device context") Signed-off-by: Fabian Bläse Cc: Jason A. Donenfeld Reviewed-by: Florian Westphal Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/icmp.c | 6 ++++-- net/ipv6/ip6_icmp.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index ac82a4158b86b..875424c428e66 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -790,11 +790,12 @@ void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info) struct sk_buff *cloned_skb = NULL; struct ip_options opts = { 0 }; enum ip_conntrack_info ctinfo; + enum ip_conntrack_dir dir; struct nf_conn *ct; __be32 orig_ip; ct = nf_ct_get(skb_in, &ctinfo); - if (!ct || !(ct->status & IPS_SRC_NAT)) { + if (!ct || !(READ_ONCE(ct->status) & IPS_NAT_MASK)) { __icmp_send(skb_in, type, code, info, &opts); return; } @@ -809,7 +810,8 @@ void icmp_ndo_send(struct sk_buff *skb_in, int type, int code, __be32 info) goto out; orig_ip = ip_hdr(skb_in)->saddr; - ip_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.ip; + dir = CTINFO2DIR(ctinfo); + ip_hdr(skb_in)->saddr = ct->tuplehash[dir].tuple.src.u3.ip; __icmp_send(skb_in, type, code, info, &opts); ip_hdr(skb_in)->saddr = orig_ip; out: diff --git a/net/ipv6/ip6_icmp.c b/net/ipv6/ip6_icmp.c index 9e3574880cb03..233914b63bdb8 100644 --- a/net/ipv6/ip6_icmp.c +++ b/net/ipv6/ip6_icmp.c @@ -54,11 +54,12 @@ void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info) struct inet6_skb_parm parm = { 0 }; struct sk_buff *cloned_skb = NULL; enum ip_conntrack_info ctinfo; + enum ip_conntrack_dir dir; struct in6_addr orig_ip; struct nf_conn *ct; ct = nf_ct_get(skb_in, &ctinfo); - if (!ct || !(ct->status & IPS_SRC_NAT)) { + if (!ct || !(READ_ONCE(ct->status) & IPS_NAT_MASK)) { __icmpv6_send(skb_in, type, code, info, &parm); return; } @@ -73,7 +74,8 @@ void icmpv6_ndo_send(struct sk_buff *skb_in, u8 type, u8 code, __u32 info) goto out; orig_ip = ipv6_hdr(skb_in)->saddr; - ipv6_hdr(skb_in)->saddr = ct->tuplehash[0].tuple.src.u3.in6; + dir = CTINFO2DIR(ctinfo); + ipv6_hdr(skb_in)->saddr = ct->tuplehash[dir].tuple.src.u3.in6; __icmpv6_send(skb_in, type, code, info, &parm); ipv6_hdr(skb_in)->saddr = orig_ip; out: -- 2.50.1