From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 22857320CAD; Sat, 30 May 2026 17:59:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163968; cv=none; b=XCYYT7b+l7+sdGpmxWNqdGLVmOrpZhIh3s8tXrWHb9FT9dFHvgt0Iuw14UTjedPBoCHHkDMV7YjpEbORBl0GRQx4aiuE1LVcbfsMOTLPz/qCGl16E+l3GjIrINVvNvpIBpmBi2dw+X9liq55I/lpCgGu2hvDoCvfR1RlL1mr8Wo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163968; c=relaxed/simple; bh=YlelWltdBvgpM47l8K0wV8oazfcGYaTegfnOlEbSMg4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RO4+EKAKmhpQLU5KliImCVPqJhNJvoxbAKuiE00mqcSxEvt4gVZleltGUGP64ouoWDjUEy97mxFJi0pYk7WWS6IK3axxIoL/k+5GGGbsbToszmZXE8VWDWmhNGZj9Z+S+jj5aWrrnWAeyk5ZHmb8gg9TcPtDTwIUIgy29fOnMog= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UAE0rO26; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="UAE0rO26" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 677121F00893; Sat, 30 May 2026 17:59:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780163967; bh=nkzcDhs+zu8hukBu2APrOArs1ZM1IMsUd6Ob5kkKg4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UAE0rO26sFDfrDI2yPtdU8mYYUGBt9KlwpYPkDnPvxY8LzzU5cAh2/wYZtUfX7F+q MwcV9z3l1e1im/e50h0NvwSIeMkx8sii/b0oomfTM3WmWrPcn+Kb201VhVmp6PlvZB Enm749TCojuoIKWKOu2lNSs2mb/Qnv7jEnYOByZg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Sasha Levin Subject: [PATCH 5.15 415/776] netfilter: nft_fwd_netdev: check ttl/hl before forwarding Date: Sat, 30 May 2026 18:02:09 +0200 Message-ID: <20260530160251.202959824@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit 1dfd95bdf4d18d263aa8fad06bfb9f4d9c992b18 ] Drop packets if their ttl/hl is too small for forwarding. Fixes: d32de98ea70f ("netfilter: nft_fwd_netdev: allow to forward packets via neighbour layer") Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- net/netfilter/nft_fwd_netdev.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c index 7730409f6f091..09aff403884b5 100644 --- a/net/netfilter/nft_fwd_netdev.c +++ b/net/netfilter/nft_fwd_netdev.c @@ -113,6 +113,11 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr, goto out; } iph = ip_hdr(skb); + if (iph->ttl <= 1) { + verdict = NF_DROP; + goto out; + } + ip_decrease_ttl(iph); neigh_table = NEIGH_ARP_TABLE; break; @@ -129,6 +134,11 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr, goto out; } ip6h = ipv6_hdr(skb); + if (ip6h->hop_limit <= 1) { + verdict = NF_DROP; + goto out; + } + ip6h->hop_limit--; neigh_table = NEIGH_ND_TABLE; break; -- 2.53.0