]> git.karo-electronics.de Git - karo-tx-linux.git/commitdiff
macvtap: Fix csum_start when VLAN tags are present
authorHerbert Xu <herbert@gondor.apana.org.au>
Mon, 3 Nov 2014 06:01:25 +0000 (14:01 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 21 Nov 2014 17:23:01 +0000 (09:23 -0800)
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 <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/macvtap.c

index 9b5481c70b4c460a33a0f825418ef32fc7ca58e9..07c942b6ae011bc1d96d2e7a5e97ed2d3ffe4c24 100644 (file)
@@ -629,6 +629,8 @@ static void 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;