From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 5 Dec 2010 18:50:32 +0000 (+0000)
Subject: net: fix skb_defer_rx_timestamp()
X-Git-Tag: firefly_0821_release~9833^2~71^2^2~75
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b1b27e4a677bc8c92b3c83541b4981c000934bc2;p=firefly-linux-kernel-4.4.55.git

net: fix skb_defer_rx_timestamp()

[ 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>
---

diff --git a/net/core/timestamping.c b/net/core/timestamping.c
index 0ae6c22da85b..c19bb4ee405e 100644
--- a/net/core/timestamping.c
+++ b/net/core/timestamping.c
@@ -96,11 +96,13 @@ bool skb_defer_rx_timestamp(struct sk_buff *skb)
 	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: