netdev - [net v2] net: fix double free issue of skbuff

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Message-Id: <1456756291-23950-1-git-send-email-zhangshengju@cmss.chinamobile.com>
Date:	Mon, 29 Feb 2016 14:31:31 +0000
From:	Zhang Shengju <zhangshengju@...s.chinamobile.com>
To:	davem@...emloft.net, netdev@...r.kernel.org
Subject: [net v2] net: fix double free issue of skbuff

If skb_reorder_vlan_header() failed, skb is freed and NULL is returned.
Then at skb_vlan_untag(), it will free skbuff again which cause double free.

This patch removes kfree_skb() call in function skb_reorder_vlan_header().

Signed-off-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>
---
 net/core/skbuff.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 488566b..a5f2401 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -4349,10 +4349,8 @@ EXPORT_SYMBOL_GPL(skb_gso_transport_seglen);
 
 static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb)
 {
-	if (skb_cow(skb, skb_headroom(skb)) < 0) {
-		kfree_skb(skb);
+	if (skb_cow(skb, skb_headroom(skb)) < 0)
 		return NULL;
-	}
 
 	memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len - VLAN_HLEN,
 		2 * ETH_ALEN);
-- 
1.8.3.1