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 1488F3A4526; Wed, 20 May 2026 17:22:07 +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=1779297729; cv=none; b=Lb1j3p/hTeJ3msMAOfmSD0Pht0vfbVAFV1019sdFbBFfHXBx96oTOnSq5ZkYYyw8+24F4CJxlGswYfTskA91Urh1djc4LSXZOHlt13BFLNh1ijwAYmrIGDkAaV8YicUTliLa8vUH3HVtn+MJl+RyYz3q2cZxu7XtQfd7zNyVUpo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779297729; c=relaxed/simple; bh=3Y61Kp+CilqduWtI34GBdm/C+TP2yjWlrEA8A0uEjWA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Vcai7e/Rh1/rCu7IkUZTQvW702SHg8iyE9kaVbhrQfhKohvd6DzJ9FSAAOh53pTbDJBnNw4cvAmF1aIo9AGZurQNvJgORsyZEdcxYo9sf1kbTZR8rEeP6Ap/zfCNAUpHxDOS1FXbPHo5LOMvprv7G7goaVhcZfXfOGHDo12SiPY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NT7zWGS0; 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="NT7zWGS0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B30B1F000E9; Wed, 20 May 2026 17:22:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1779297727; bh=KqK1dnQXw60/lgbv46/49MnP53C4/sTvLr3O2bE/4xc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=NT7zWGS0SoU+ZQhQKcHYRxFnbEiSNqWmFy1flDpBCQHy3EM1VfOfURytV2lp/4gwq ZH5yMQ0yBXrxDyHEZbRmDC7py6ULeKI1xU0IWQ4XCIKSy7yHVjHF5Ggq7z3ZMTXyBo oOPSZKPLsLdugysNODl+oyOuIJZ6BJV3vHzACrQM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Sasha Levin Subject: [PATCH 6.18 142/957] netfilter: nft_fwd_netdev: check ttl/hl before forwarding Date: Wed, 20 May 2026 18:10:25 +0200 Message-ID: <20260520162137.634069573@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260520162134.554764788@linuxfoundation.org> References: <20260520162134.554764788@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 6.18-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 152a9fb4d23af..256e832f1bb99 100644 --- a/net/netfilter/nft_fwd_netdev.c +++ b/net/netfilter/nft_fwd_netdev.c @@ -116,6 +116,11 @@ 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; @@ -132,6 +137,11 @@ 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