From: John Fastabend <john.fastabend@gmail.com>
Date: Mon, 11 Jan 2016 05:38:44 +0000 (-0800)
Subject: net: pktgen: fix null ptr deref in skb allocation
X-Git-Tag: v4.3.5~57
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fe8383327a1b33501be00f810a7b3397c2d20616;p=thirdparty%2Fkernel%2Fstable.git

net: pktgen: fix null ptr deref in skb allocation

[ Upstream commit 3de03596dfeee48bc803c1d1a6daf60a459929f3 ]

Fix possible null pointer dereference that may occur when calling
skb_reserve() on a null skb.

Fixes: 879c7220e82 ("net: pktgen: Observe needed_headroom of the device")
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index de8d5cc5eb240..4da4d51a2ccfd 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -2787,7 +2787,9 @@ static struct sk_buff *pktgen_alloc_skb(struct net_device *dev,
 	} else {
 		 skb = __netdev_alloc_skb(dev, size, GFP_NOWAIT);
 	}
-	skb_reserve(skb, LL_RESERVED_SPACE(dev));
+
+	if (likely(skb))
+		skb_reserve(skb, LL_RESERVED_SPACE(dev));
 
 	return skb;
 }