From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761672AbbA1Een (ORCPT ); Tue, 27 Jan 2015 23:34:43 -0500 Received: from mail.kernel.org ([198.145.29.136]:41103 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965202AbbA1EZ1 (ORCPT ); Tue, 27 Jan 2015 23:25:27 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Herbert Xu , "David S. Miller" , Zefan Li Subject: [PATCH 3.4 151/177] macvtap: Fix csum_start when VLAN tags are present Date: Wed, 28 Jan 2015 12:10:09 +0800 Message-Id: <1422418236-12852-242-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422418050-12581-1-git-send-email-lizf@kernel.org> References: <1422418050-12581-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Herbert Xu 3.4.106-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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 Cheers, Signed-off-by: David S. Miller Signed-off-by: Zefan Li --- drivers/net/macvtap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index f5b9de4..f0e3764 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -634,6 +634,8 @@ static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, 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; -- 1.9.1