Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753926AbaFEEYH (ORCPT ); Thu, 5 Jun 2014 00:24:07 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44615 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753781AbaFEEWm (ORCPT ); Thu, 5 Jun 2014 00:22:42 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wei Liu , Ian Campbell , "David S. Miller" , Ben Hutchings , Qiang Huang Subject: [PATCH 3.4 212/214] xen-netfront: reduce gso_max_size to account for max TCP header Date: Wed, 4 Jun 2014 21:19:35 -0700 Message-Id: <20140605041707.988595332@linuxfoundation.org> X-Mailer: git-send-email 2.0.0 In-Reply-To: <20140605041639.638675216@linuxfoundation.org> References: <20140605041639.638675216@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wei Liu commit 9ecd1a75d977e2e8c48139c7d3efed183f898d94 upstream. The maximum packet including header that can be handled by netfront / netback wire format is 65535. Reduce gso_max_size accordingly. Drop skb and print warning when skb->len > 65535. This can 1) save the effort to send malformed packet to netback, 2) help spotting misconfiguration of netfront in the future. Signed-off-by: Wei Liu Acked-by: Ian Campbell Signed-off-by: David S. Miller [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings [hq: Backported to 3.4: adjust context] Signed-off-by: Qiang Huang Signed-off-by: Greg Kroah-Hartman --- drivers/net/xen-netfront.c | 17 +++++++++++++++-- include/xen/interface/io/netif.h | 1 + 2 files changed, 16 insertions(+), 2 deletions(-) --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -36,7 +36,7 @@ #include #include #include -#include +#include #include #include #include @@ -492,6 +492,16 @@ static int xennet_start_xmit(struct sk_b unsigned int len = skb_headlen(skb); unsigned long flags; + /* If skb->len is too big for wire format, drop skb and alert + * user about misconfiguration. + */ + if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) { + net_alert_ratelimited( + "xennet: skb->len = %u, too big for wire format\n", + skb->len); + goto drop; + } + frags += DIV_ROUND_UP(offset + len, PAGE_SIZE); if (unlikely(frags > MAX_SKB_FRAGS + 1)) { printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n", @@ -1045,7 +1055,8 @@ err: static int xennet_change_mtu(struct net_device *dev, int mtu) { - int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN; + int max = xennet_can_sg(dev) ? + XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER : ETH_DATA_LEN; if (mtu > max) return -EINVAL; @@ -1349,6 +1360,8 @@ static struct net_device * __devinit xen SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops); SET_NETDEV_DEV(netdev, &dev->dev); + netif_set_gso_max_size(netdev, XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER); + np->netdev = netdev; netif_carrier_off(netdev); --- a/include/xen/interface/io/netif.h +++ b/include/xen/interface/io/netif.h @@ -65,6 +65,7 @@ #define _XEN_NETTXF_extra_info (3) #define XEN_NETTXF_extra_info (1U<<_XEN_NETTXF_extra_info) +#define XEN_NETIF_MAX_TX_SIZE 0xFFFF struct xen_netif_tx_request { grant_ref_t gref; /* Reference to buffer page */ uint16_t offset; /* Offset within buffer page */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/