From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 649CDC43334 for ; Tue, 26 Jul 2022 10:42:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232504AbiGZKmU (ORCPT ); Tue, 26 Jul 2022 06:42:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39942 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230198AbiGZKmT (ORCPT ); Tue, 26 Jul 2022 06:42:19 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B1DD1EAD7 for ; Tue, 26 Jul 2022 03:42:18 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1oGI11-0005er-De; Tue, 26 Jul 2022 12:42:15 +0200 From: Florian Westphal To: Cc: Florian Westphal , Domingo Dirutigliano Subject: [PATCH nf] netfilter: nf_queue: do not allow packet truncation below transport header offset Date: Tue, 26 Jul 2022 12:42:06 +0200 Message-Id: <20220726104206.2036-1-fw@strlen.de> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Domingo Dirutigliano and Nicola Guerrera report kernel panic when sending nf_queue verdict with 1-byte nfta_payload attribute. The IP/IPv6 stack pulls the IP(v6) header from the packet after the input hook. If user truncates the packet below the header size, this skb_pull() will result in a malformed skb (skb->len < 0). Fixes: 7af4cc3fa158 ("[NETFILTER]: Add "nfnetlink_queue" netfilter queue handler over nfnetlink") Reported-by: Domingo Dirutigliano Signed-off-by: Florian Westphal --- net/netfilter/nfnetlink_queue.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index a364f8e5e698..87a9009d5234 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -843,11 +843,16 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum) } static int -nfqnl_mangle(void *data, int data_len, struct nf_queue_entry *e, int diff) +nfqnl_mangle(void *data, unsigned int data_len, struct nf_queue_entry *e, int diff) { struct sk_buff *nskb; if (diff < 0) { + unsigned int min_len = skb_transport_offset(e->skb); + + if (data_len < min_len) + return -EINVAL; + if (pskb_trim(e->skb, data_len)) return -ENOMEM; } else if (diff > 0) { -- 2.35.1