From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wei Liu Subject: [PATCH 2/4] xen-netfront: drop skb when skb->len > 65535 Date: Mon, 18 Mar 2013 10:35:53 +0000 Message-ID: <1363602955-24790-3-git-send-email-wei.liu2@citrix.com> References: <1363602955-24790-1-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain Cc: , , , Wei Liu To: , Return-path: Received: from smtp.citrix.com ([66.165.176.89]:23973 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751021Ab3CRKgO (ORCPT ); Mon, 18 Mar 2013 06:36:14 -0400 In-Reply-To: <1363602955-24790-1-git-send-email-wei.liu2@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: The `size' field of Xen network wire format is uint16_t, anything bigger than 65535 will cause overflow. Signed-off-by: Wei Liu --- drivers/net/xen-netfront.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 5527663..8c3d065 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -547,6 +547,18 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) unsigned int len = skb_headlen(skb); unsigned long flags; + /* + * wire format of xen_netif_tx_request only supports skb->len + * < 64K, because size field in xen_netif_tx_request is + * uint16_t. + */ + if (unlikely(skb->len > (uint16_t)(~0))) { + net_alert_ratelimited( + "xennet: skb->len = %d, too big for wire format\n", + skb->len); + goto drop; + } + slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) + xennet_count_skb_frag_slots(skb); if (unlikely(slots > MAX_SKB_FRAGS + 1)) { -- 1.7.10.4