From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794063544; b=xabRH6FOFa92iIPJmtnSD7UIDytyJFXSfkRJxtUSyeS0G+j3zuXKobz3FHT1MakFbLVz v5qIhoRPRPEGd2OK36lGwOB+vOIZej7TufhAEmXPA6tO31yyFqCbSLIXJK9VHpSqvfa9I V5tsJKimhWZ0bgEO1j6JiZYvoC761FrVey9RYmgmuVRamp3ZNe1X3HGVMsREQXUYDntkL auP0AsecO57EzSGULEM+TU1ZyRNEM7i2aoecVXF6cDYpNM8A4ApW2Xu0x3QDxkUEocHK7 j1b72G7D9hyi0W8ylG1mLk8DRSwc0zJCz8Vnpe5xl+yiFof9Ypf+FAzHeMrhcXv6axg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063544; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=baKXKnaKIxqHRpeZCEkztH2AZVHCHSqCyEdCPVNjU2s=; b=PE+JnQBirQzd/UGoPCvb4KnUfUdebca1H0J28ChLXwQoBUcvJjK5N6uaIQ+9s2HvkkVx 5Gv7fyGAAsiI2NGlmb65GgasTsSI9yKIjNvg7C3/wfgQ6sfN55WTbLMUK1bTnlfg7auo0 d9EWiJNuX+2sVLhb5zYWGdj1j2mGUdc87M6wyfGtYVQa14IW0MOJ7DAu+mgSUUht9gg3z fUycoYu+Z5b0ZmBxkrLVsVwo0XE+R2gwMWYjj1qoGg8kTeRTBCzGXglKotut0AKaPCLfb MCqt78mJE0bjHjaa0ioeBBHndlzqyG9/Ly7lF1ZG0FSz+TE+Y0s6gSor6nuEJWAnDkQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="mWf/wAX3"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 199C66083606; Sat, 7 Nov 2026 14:59:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=mWf/wAX3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBF691F0089F; Sat, 7 Nov 2026 14:59:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063544; bh=baKXKnaKIxqHRpeZCEkztH2AZVHCHSqCyEdCPVNjU2s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mWf/wAX34gO6EOAS34BMRBbtjBDyC6v7RbU3T206sa2MGeT7NwDICF4524IA7t4Uh QCek+Ce7NEX/ljwGdMovOiOa+bwHx7y8vGZY+MW8Aki5JehPvfkBaAkCoL58qCtBrf ifcgqMdPw4mC9BooQNx3rlvyvUWtjMmd/jFEhWYk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kyle Zeng , David Lee , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 6.18 643/869] netfilter: nf_reject: initialize IPCB at inet ingress Date: Sat, 7 Nov 2026 08:55:25 -0500 Message-ID: <20261107134914.724557505@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kyle Zeng [ Upstream commit 73a73d442f9986353fe284bd1b504d0313d0f153 ] The inet ingress hook runs before ip_rcv_core() and ip6_rcv_core(), so neither IPCB nor IP6CB has been initialized when nft_reject_inet passes a packet to nf_send_unreach() or nf_send_unreach6(). skb->cb can therefore retain metadata from an earlier protocol layer. For IPv4, icmp_send() treats IPCB(skb)->opt as parsed IPv4 options. Stale option offsets can make __ip_options_echo() copy an attacker-controlled length into its 40-byte reply option buffer and overflow the stack. On an unpatched v7.2-rc5 kernel, the IPv4 reproducer produced: BUG: KASAN: stack-out-of-bounds in __ip_options_echo() Write of size 255 For IPv6, icmpv6_send() consumes IP6CB(skb) as parsed IPv6 metadata. It always uses iif for source selection and, when MIP6 is enabled, uses dsthao as an extension-header offset. These fields must not be stale. For NF_INET_INGRESS, clear the address-family-specific control block and restore its input interface before constructing the ICMP error. This matches similar initialization normally performed by ip_rcv_core() and ip6_rcv_core(). Fixes: 117ca1f8920c ("netfilter: nft_reject_inet: allow to use reject from inet ingress") Cc: stable@vger.kernel.org Assisted-by: Codex:gpt-5.6-sol Codex:gpt-5.5-cyber Signed-off-by: Kyle Zeng Co-developed-by: David Lee Signed-off-by: David Lee Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/ipv4/netfilter/nf_reject_ipv4.c | 5 +++++ net/ipv6/netfilter/nf_reject_ipv6.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index 59ec465a9df98..7cb33af671e26 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -357,6 +357,11 @@ void nf_send_unreach(struct sk_buff *skb_in, int code, int hook) if (!skb_valid_dst(skb_in) && nf_reject_fill_skb_dst(skb_in) < 0) return; + if (hook == NF_INET_INGRESS) { + memset(IPCB(skb_in), 0, sizeof(*IPCB(skb_in))); + IPCB(skb_in)->iif = skb_in->skb_iif; + } + if (skb_csum_unnecessary(skb_in) || !nf_reject_verify_csum(skb_in, dataoff, proto)) { icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); diff --git a/net/ipv6/netfilter/nf_reject_ipv6.c b/net/ipv6/netfilter/nf_reject_ipv6.c index 07cdaa10da0d0..5e08d8529cc88 100644 --- a/net/ipv6/netfilter/nf_reject_ipv6.c +++ b/net/ipv6/netfilter/nf_reject_ipv6.c @@ -444,6 +444,11 @@ 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_INGRESS) { + memset(IP6CB(skb_in), 0, sizeof(*IP6CB(skb_in))); + IP6CB(skb_in)->iif = skb_in->skb_iif; + } + if (!skb_valid_dst(skb_in) && nf_reject6_fill_skb_dst(skb_in) < 0) return; -- 2.53.0