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 0FDC127E049; Mon, 23 Mar 2026 16:14:59 +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=1774282499; cv=none; b=YZsst8EFgMiqO4QeyfTAQZjgmbBEuSZHVjqD79Jvmd0oFHGJJqYh2L8CF7c5symxmzN/gOGVHAQxkf2/WABb9HrVZoTYpOMWL+ivGxLXGGDOxSzX7IkK0jyuFgvzoh0sMHlXwET20L8zGK1TERKySo0LxRm86w77jd8XBrWlqi8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774282499; c=relaxed/simple; bh=lrZdm6V6f+TXrN8KvqSF0cicG0WQ8xEu8wuZYyUC3fM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GKEAllRPW6zq5Q3SbA8Nzsbj/SU6s5hKzopMpIzOqZWu7jEEETxzH9pB7o/PYJSMsIFbbabSSrz4ERAp5UEdJxTnkT4BNEbSpxBt9lDX289CWPCfd0phNJwAxr7GDwPSWKd70QHrRzi1nmvqb05frBFTow+Cxp3HUR3D0/hHp7I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TLomew6h; 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="TLomew6h" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A04F4C4CEF7; Mon, 23 Mar 2026 16:14:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774282499; bh=lrZdm6V6f+TXrN8KvqSF0cicG0WQ8xEu8wuZYyUC3fM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TLomew6hbxZKNGEtR8EViUwbBFVHQ6SJHIsBl3Q9UbCp8ndH1P7kDFHZey8+Q0oRe zGM5AbwAaqecHqVYtCdAU6hIIMXr/8faA9Nv5An6YC/bESFAVitIDnP84eQn6XwBKP 0osvAd6vUWziM7Qb33FQPVii51PsUv26Tl4XHq5s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Dull , Florian Westphal , Sasha Levin Subject: [PATCH 6.1 177/481] netfilter: x_tables: guard option walkers against 1-byte tail reads Date: Mon, 23 Mar 2026 14:42:39 +0100 Message-ID: <20260323134529.528252794@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134525.256603107@linuxfoundation.org> References: <20260323134525.256603107@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Dull [ Upstream commit cfe770220ac2dbd3e104c6b45094037455da81d4 ] When the last byte of options is a non-single-byte option kind, walkers that advance with i += op[i + 1] ? : 1 can read op[i + 1] past the end of the option area. Add an explicit i == optlen - 1 check before dereferencing op[i + 1] in xt_tcpudp and xt_dccp option walkers. Fixes: 2e4e6a17af35 ("[NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables") Signed-off-by: David Dull Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- net/netfilter/xt_dccp.c | 4 ++-- net/netfilter/xt_tcpudp.c | 6 ++++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/net/netfilter/xt_dccp.c b/net/netfilter/xt_dccp.c index e5a13ecbe67a0..037ab93e25d0a 100644 --- a/net/netfilter/xt_dccp.c +++ b/net/netfilter/xt_dccp.c @@ -62,10 +62,10 @@ dccp_find_option(u_int8_t option, return true; } - if (op[i] < 2) + if (op[i] < 2 || i == optlen - 1) i++; else - i += op[i+1]?:1; + i += op[i + 1] ? : 1; } spin_unlock_bh(&dccp_buflock); diff --git a/net/netfilter/xt_tcpudp.c b/net/netfilter/xt_tcpudp.c index 11ec2abf0c727..73f50dc01b19f 100644 --- a/net/netfilter/xt_tcpudp.c +++ b/net/netfilter/xt_tcpudp.c @@ -56,8 +56,10 @@ tcp_find_option(u_int8_t option, for (i = 0; i < optlen; ) { if (op[i] == option) return !invert; - if (op[i] < 2) i++; - else i += op[i+1]?:1; + if (op[i] < 2 || i == optlen - 1) + i++; + else + i += op[i + 1] ? : 1; } return invert; -- 2.51.0