[PATCH 3.16.y-ckt 070/170] vxlan: fix a use after free in vxlan_encap_bypass

From: Luis Henriques
Date: Tue Nov 11 2014 - 06:10:18 EST


3.16.7-ckt1 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Li RongQing <roy.qing.li@xxxxxxxxx>

commit ce6502a8f9572179f044a4d62667c4645256d6e4 upstream.

when netif_rx() is done, the netif_rx handled skb maybe be freed,
and should not be used.

Signed-off-by: Li RongQing <roy.qing.li@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/net/vxlan.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c
index 31a7ad0d7d5f..a5da8d49a824 100644
--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -1734,6 +1734,8 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,
struct pcpu_sw_netstats *tx_stats, *rx_stats;
union vxlan_addr loopback;
union vxlan_addr *remote_ip = &dst_vxlan->default_dst.remote_ip;
+ struct net_device *dev = skb->dev;
+ int len = skb->len;

tx_stats = this_cpu_ptr(src_vxlan->dev->tstats);
rx_stats = this_cpu_ptr(dst_vxlan->dev->tstats);
@@ -1757,16 +1759,16 @@ static void vxlan_encap_bypass(struct sk_buff *skb, struct vxlan_dev *src_vxlan,

u64_stats_update_begin(&tx_stats->syncp);
tx_stats->tx_packets++;
- tx_stats->tx_bytes += skb->len;
+ tx_stats->tx_bytes += len;
u64_stats_update_end(&tx_stats->syncp);

if (netif_rx(skb) == NET_RX_SUCCESS) {
u64_stats_update_begin(&rx_stats->syncp);
rx_stats->rx_packets++;
- rx_stats->rx_bytes += skb->len;
+ rx_stats->rx_bytes += len;
u64_stats_update_end(&rx_stats->syncp);
} else {
- skb->dev->stats.rx_dropped++;
+ dev->stats.rx_dropped++;
}
}

--
2.1.0

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