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 20ECA2192F2; Tue, 26 Aug 2025 14:27:22 +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=1756218442; cv=none; b=nuI4tOzxASmLhNLuPSCMJxYJ5WeY3ewLsI2fSypRDxreyUjTKj8ZlAuRjF2Saywh13MB9RmD2KYHbRPc+z/G290KdqBQmTg4tHxdhTjOulV7gEpDsZaiJn08RuQ/i+MMcycagcDMuJd+zIEvdegrQfYEcbp5ZQTELYZ2CyfdL64= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756218442; c=relaxed/simple; bh=nCRFBH3vu1h2sIn+8ofInNmtnhrItilCaMiJ9lIE92I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PgVx2tBb1g3VZyy8NEsbNeGyoNThUw1VLeKrPXIlcbo/FuU8dNuHcCoCCDV3AdowvDmcoZCOc4Q4HoKvrSluSLcVO5B6QFYIrscn8M12sY36KkERl6UIysFhkHko/zTWyZCe+uMlGsQKNCQzzU7wAZPE8ZGJ2e9CSAyh7a1G6Z8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=D0YSskjn; 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="D0YSskjn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9F1DC4CEF1; Tue, 26 Aug 2025 14:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1756218442; bh=nCRFBH3vu1h2sIn+8ofInNmtnhrItilCaMiJ9lIE92I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D0YSskjnTYziRMBV/hdcGyoa2HQrVwplv0ImksQ4zlJVHUZ8p0oiMwb+ny1nSAx7k XFoykGm6Hf7w/0VnnRWVry71n8mLloqOIGa9rZHyRAOQ9KTq6cJW8v88zWRXLd//1V A/GI6R52Bqk7zPihd0Ytq9jR1nGr0stoKh8IrFeo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 523/523] netfilter: nf_reject: dont leak dst refcount for loopback packets Date: Tue, 26 Aug 2025 13:12:13 +0200 Message-ID: <20250826110937.339124694@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250826110924.562212281@linuxfoundation.org> References: <20250826110924.562212281@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-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit 91a79b792204313153e1bdbbe5acbfc28903b3a5 ] recent patches to add a WARN() when replacing skb dst entry found an old bug: WARNING: include/linux/skbuff.h:1165 skb_dst_check_unset include/linux/skbuff.h:1164 [inline] WARNING: include/linux/skbuff.h:1165 skb_dst_set include/linux/skbuff.h:1210 [inline] WARNING: include/linux/skbuff.h:1165 nf_reject_fill_skb_dst+0x2a4/0x330 net/ipv4/netfilter/nf_reject_ipv4.c:234 [..] Call Trace: nf_send_unreach+0x17b/0x6e0 net/ipv4/netfilter/nf_reject_ipv4.c:325 nft_reject_inet_eval+0x4bc/0x690 net/netfilter/nft_reject_inet.c:27 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline] .. This is because blamed commit forgot about loopback packets. Such packets already have a dst_entry attached, even at PRE_ROUTING stage. Instead of checking hook just check if the skb already has a route attached to it. Fixes: f53b9b0bdc59 ("netfilter: introduce support for reject at prerouting stage") Signed-off-by: Florian Westphal Link: https://patch.msgid.link/20250820123707.10671-1-fw@strlen.de Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/netfilter/nf_reject_ipv4.c | 6 ++---- net/ipv6/netfilter/nf_reject_ipv6.c | 5 ++--- 2 files changed, 4 insertions(+), 7 deletions(-) diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index d232e0251142..e89a4cbd9f5d 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -125,8 +125,7 @@ void nf_send_reset(struct net *net, struct sock *sk, struct sk_buff *oldskb, if (!oth) return; - if ((hook == NF_INET_PRE_ROUTING || hook == NF_INET_INGRESS) && - nf_reject_fill_skb_dst(oldskb) < 0) + if (!skb_dst(oldskb) && nf_reject_fill_skb_dst(oldskb) < 0) return; if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST)) @@ -194,8 +193,7 @@ void nf_send_unreach(struct sk_buff *skb_in, int code, int hook) if (iph->frag_off & htons(IP_OFFSET)) return; - if ((hook == NF_INET_PRE_ROUTING || hook == NF_INET_INGRESS) && - nf_reject_fill_skb_dst(skb_in) < 0) + if (!skb_dst(skb_in) && nf_reject_fill_skb_dst(skb_in) < 0) return; if (skb_csum_unnecessary(skb_in) || !nf_reject_verify_csum(proto)) { diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c index b396559f68b4..5384b73e318e 100644 --- a/net/ipv6/netfilter/nf_reject_ipv6.c +++ b/net/ipv6/netfilter/nf_reject_ipv6.c @@ -161,7 +161,7 @@ void nf_send_reset6(struct net *net, struct sock *sk, struct sk_buff *oldskb, fl6.fl6_sport = otcph->dest; fl6.fl6_dport = otcph->source; - if (hook == NF_INET_PRE_ROUTING || hook == NF_INET_INGRESS) { + if (!skb_dst(oldskb)) { nf_ip6_route(net, &dst, flowi6_to_flowi(&fl6), false); if (!dst) return; @@ -259,8 +259,7 @@ void nf_send_unreach6(struct net *net, struct sk_buff *skb_in, if (hooknum == NF_INET_LOCAL_OUT && skb_in->dev == NULL) skb_in->dev = net->loopback_dev; - if ((hooknum == NF_INET_PRE_ROUTING || hooknum == NF_INET_INGRESS) && - nf_reject6_fill_skb_dst(skb_in) < 0) + if (!skb_dst(skb_in) && nf_reject6_fill_skb_dst(skb_in) < 0) return; icmpv6_send(skb_in, ICMPV6_DEST_UNREACH, code, 0); -- 2.50.1