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 <stable@xxxxxxxxxxxxxxx> know about it. >From 9ecd1a75d977e2e8c48139c7d3efed183f898d94 Mon Sep 17 00:00:00 2001 From: Wei Liu <wei.liu2@xxxxxxxxxx> 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 <wei.liu2@xxxxxxxxxx> 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 <wei.liu2@xxxxxxxxxx> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 wei.liu2@xxxxxxxxxx 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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html