From: Myungho Jung <mhjungk@gmail.com>
Date: Tue, 25 Apr 2017 18:58:15 +0000 (-0700)
Subject: net: core: Prevent from dereferencing null pointer when releasing SKB
X-Git-Tag: v4.11~14^2~3
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=9899886d5e8ec5b343b1efe44f185a0e68dc6454;p=linux.git

net: core: Prevent from dereferencing null pointer when releasing SKB

Added NULL check to make __dev_kfree_skb_irq consistent with kfree
family of functions.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=195289

Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index 533a6d6f6092..9b5875388c23 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2450,6 +2450,9 @@ void __dev_kfree_skb_irq(struct sk_buff *skb, enum skb_free_reason reason)
 {
 	unsigned long flags;
 
+	if (unlikely(!skb))
+		return;
+
 	if (likely(atomic_read(&skb->users) == 1)) {
 		smp_rmb();
 		atomic_set(&skb->users, 0);