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 D3E63C54EBC for ; Wed, 11 Jan 2023 21:23:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233101AbjAKVXE (ORCPT ); Wed, 11 Jan 2023 16:23:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229935AbjAKVXA (ORCPT ); Wed, 11 Jan 2023 16:23:00 -0500 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DFE78E53 for ; Wed, 11 Jan 2023 13:22:58 -0800 (PST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Subject: [PATCH net 3/3] netfilter: nft_payload: incorrect arithmetics when fetching VLAN header bits Date: Wed, 11 Jan 2023 22:22:51 +0100 Message-Id: <20230111212251.193032-4-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20230111212251.193032-1-pablo@netfilter.org> References: <20230111212251.193032-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org If the offset + length goes over the ethernet + vlan header, then the length is adjusted to copy the bytes that are within the boundaries of the vlan_ethhdr scratchpad area. The remaining bytes beyond ethernet + vlan header are copied directly from the skbuff data area. Fix incorrect arithmetic operator: subtract, not add, the size of the vlan header in case of double-tagged packets to adjust the length accordingly to address CVE-2023-0179. Reported-by: Davide Ornaghi Fixes: f6ae9f120dad ("netfilter: nft_payload: add C-VLAN support") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_payload.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index 17b418a5a593..3a3c7746e88f 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -63,7 +63,7 @@ nft_payload_copy_vlan(u32 *d, const struct sk_buff *skb, u8 offset, u8 len) return false; if (offset + len > VLAN_ETH_HLEN + vlan_hlen) - ethlen -= offset + len - VLAN_ETH_HLEN + vlan_hlen; + ethlen -= offset + len - VLAN_ETH_HLEN - vlan_hlen; memcpy(dst_u8, vlanh + offset - vlan_hlen, ethlen); -- 2.30.2