From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Tu Subject: [net-next,v2] ip_gre: check packet length and mtu correctly in erspan tx Date: Thu, 5 Oct 2017 12:07:12 -0700 Message-ID: <1507230432-56495-1-git-send-email-u9012063@gmail.com> Cc: Xin Long , David Laight To: netdev@vger.kernel.org Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:33181 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751369AbdJEWJF (ORCPT ); Thu, 5 Oct 2017 18:09:05 -0400 Received: by mail-pf0-f194.google.com with SMTP id m28so15274399pfi.0 for ; Thu, 05 Oct 2017 15:09:05 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: Similarly to early patch for erspan_xmit(), the ARPHDR_ETHER device is the length of the whole ether packet. So skb->len should subtract the dev->hard_header_len. Fixes: 1a66a836da63 ("gre: add collect_md mode to ERSPAN tunnel") Fixes: 84e54fe0a5ea ("gre: introduce native tunnel support for ERSPAN") Signed-off-by: William Tu Cc: Xin Long Cc: David Laight --- v1->v2: use addition to avoid overflow fix pskb_trim size --- net/ipv4/ip_gre.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index b279c325c7f6..fb95f68d6e53 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -579,8 +579,8 @@ static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev, if (gre_handle_offloads(skb, false)) goto err_free_rt; - if (skb->len > dev->mtu) { - pskb_trim(skb, dev->mtu); + if (skb->len > dev->mtu + dev->hard_header_len) { + pskb_trim(skb, dev->mtu + dev->hard_header_len); truncate = true; } @@ -731,8 +731,8 @@ static netdev_tx_t erspan_xmit(struct sk_buff *skb, if (skb_cow_head(skb, dev->needed_headroom)) goto free_skb; - if (skb->len - dev->hard_header_len > dev->mtu) { - pskb_trim(skb, dev->mtu); + if (skb->len > dev->mtu + dev->hard_header_len) { + pskb_trim(skb, dev->mtu + dev->hard_header_len); truncate = true; } -- 2.7.4