From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934074AbaKSWD6 (ORCPT ); Wed, 19 Nov 2014 17:03:58 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:56468 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933406AbaKSVER (ORCPT ); Wed, 19 Nov 2014 16:04:17 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herbert Xu , "David S. Miller" Subject: [PATCH 3.14 032/122] macvtap: Fix csum_start when VLAN tags are present Date: Wed, 19 Nov 2014 12:51:22 -0800 Message-Id: <20141119205209.842017006@linuxfoundation.org> X-Mailer: git-send-email 2.1.3 In-Reply-To: <20141119205208.812884198@linuxfoundation.org> References: <20141119205208.812884198@linuxfoundation.org> User-Agent: quilt/0.63-1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu commit 3ce9b20f1971690b8b3b620e735ec99431573b39 upstream. When VLAN is in use in macvtap_put_user, we end up setting csum_start to the wrong place. The result is that the whoever ends up doing the checksum setting will corrupt the packet instead of writing the checksum to the expected location, usually this means writing the checksum with an offset of -4. This patch fixes this by adjusting csum_start when VLAN tags are detected. Fixes: f09e2249c4f5 ("macvtap: restore vlan header on user read") Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: David S. Miller --- drivers/net/macvtap.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -629,6 +629,8 @@ static void macvtap_skb_to_vnet_hdr(cons if (skb->ip_summed == CHECKSUM_PARTIAL) { vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; vnet_hdr->csum_start = skb_checksum_start_offset(skb); + if (vlan_tx_tag_present(skb)) + vnet_hdr->csum_start += VLAN_HLEN; vnet_hdr->csum_offset = skb->csum_offset; } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;