From patchwork Thu Aug 20 12:28:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 1348359 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=huawei.com Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4BXP9S5PXYz9sRK for ; Thu, 20 Aug 2020 22:29:48 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729867AbgHTM3r (ORCPT ); Thu, 20 Aug 2020 08:29:47 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:34814 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729347AbgHTM3h (ORCPT ); Thu, 20 Aug 2020 08:29:37 -0400 Received: from DGGEMS401-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 7A43D86F04766B046245; Thu, 20 Aug 2020 20:29:34 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS401-HUB.china.huawei.com (10.3.19.201) with Microsoft SMTP Server id 14.3.487.0; Thu, 20 Aug 2020 20:29:28 +0800 From: Miaohe Lin To: , , , , , , , , , , CC: , , Subject: [PATCH] net: Check the expect of skb->data at mac header Date: Thu, 20 Aug 2020 08:28:22 -0400 Message-ID: <20200820122822.46608-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org skb_mpls_push() and skb_mpls_pop() expect skb->data at mac header. Check this assumption or we would get wrong mac_header and network_header. Signed-off-by: Miaohe Lin --- net/core/skbuff.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e18184ffa9c3..52d2ad54aa97 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5590,6 +5590,7 @@ static void skb_mod_eth_type(struct sk_buff *skb, struct ethhdr *hdr, int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto, int mac_len, bool ethernet) { + int offset = skb->data - skb_mac_header(skb); struct mpls_shim_hdr *lse; int err; @@ -5600,6 +5601,9 @@ int skb_mpls_push(struct sk_buff *skb, __be32 mpls_lse, __be16 mpls_proto, if (skb->encapsulation) return -EINVAL; + if (WARN_ONCE(offset, "We got skb with skb->data not at mac header (offset %d)\n", offset)) + return -EINVAL; + err = skb_cow_head(skb, MPLS_HLEN); if (unlikely(err)) return err; @@ -5643,11 +5647,15 @@ EXPORT_SYMBOL_GPL(skb_mpls_push); int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto, int mac_len, bool ethernet) { + int offset = skb->data - skb_mac_header(skb); int err; if (unlikely(!eth_p_mpls(skb->protocol))) return 0; + if (WARN_ONCE(offset, "We got skb with skb->data not at mac header (offset %d)\n", offset)) + return -EINVAL; + err = skb_ensure_writable(skb, mac_len + MPLS_HLEN); if (unlikely(err)) return err;