[077/152] net: fix skb_defer_rx_timestamp()

Greg KH
2011-01-06T00:47:23Z

From: Eric Dumazet <eric.dumazet@gmail.com>

[ Upstream commit a19faf0250e09b16cac169354126404bc8aa342b ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/core/timestamping.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -96,11 +96,13 @@ bool skb_defer_rx_timestamp(struct sk_bu
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: