net: fix skb_defer_rx_timestamp()
After commit c1f19b51d1d8 (net: support time stamping in phy devices.),
kernel might crash if CONFIG_NETWORK_PHY_TIMESTAMPING=y and
skb_defer_rx_timestamp() handles a packet without an ethernet header.
Fixes kernel bugzilla #24102
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=24102
Reported-and-tested-by: Andrew Watts <akwatts@ymail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index 0ae6c22..c19bb4e 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -96,11 +96,13 @@
struct phy_device *phydev;
unsigned int type;
- skb_push(skb, ETH_HLEN);
+ if (skb_headroom(skb) < ETH_HLEN)
+ return false;
+ __skb_push(skb, ETH_HLEN);
type = classify(skb);
- skb_pull(skb, ETH_HLEN);
+ __skb_pull(skb, ETH_HLEN);
switch (type) {
case PTP_CLASS_V1_IPV4: