This is a note to let you know that I've just added the patch titled
xen-netfront: reduce gso_max_size to account for max TCP header
to the 3.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-netfront-reduce-gso_max_size-to-account-for-max-tcp-header.patch
and it can be found in the queue-3.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 9ecd1a75d977e2e8c48139c7d3efed183f898d94 Mon Sep 17 00:00:00 2001
From: Wei Liu <[email protected]>
Date: Mon, 22 Apr 2013 02:20:41 +0000
Subject: xen-netfront: reduce gso_max_size to account for max TCP header
From: Wei Liu <[email protected]>
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 <[email protected]>
Acked-by: Ian Campbell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
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 <linux/skbuff.h>
#include <linux/ethtool.h>
#include <linux/if_ether.h>
-#include <linux/tcp.h>
+#include <net/tcp.h>
#include <linux/udp.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
@@ -548,6 +548,16 @@ 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;
+ }
+
slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
xennet_count_skb_frag_slots(skb);
if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
@@ -1064,7 +1074,8 @@ 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;
@@ -1368,6 +1379,8 @@ static struct net_device *xennet_create_
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 */
Patches currently in stable-queue which might be from [email protected] are
queue-3.9/xen-netback-coalesce-slots-in-tx-path-and-fix-regressions.patch
queue-3.9/xen-netback-remove-redundent-parameter-in-netbk_count_requests.patch
queue-3.9/xen-netback-remove-skb-in-xen_netbk_alloc_page.patch
queue-3.9/xen-netback-don-t-disconnect-frontend-when-seeing-oversize-packet.patch
queue-3.9/xen-netback-avoid-allocating-variable-size-array-on-stack.patch
queue-3.9/xen-netfront-reduce-gso_max_size-to-account-for-max-tcp-header.patch
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