[PATCH v3] net: core: Prevent from dereferencing null pointer when releasing SKB

[PATCH v3] net: core: Prevent from dereferencing null pointer when releasing SKB

[Myungho Jung]

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>
---
Changes in v2:
 - Correct category in subject
Changes in v3:
 - Fix typo in subject

 net/core/dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 7869ae3..22be2a6 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);
-- 
2.7.4

Re: [PATCH v3] net: core: Prevent from dereferencing null pointer when releasing SKB

[David Miller]

From: Myungho Jung <mhjungk@gmail.com>
Date: Tue, 25 Apr 2017 11:58:15 -0700

> 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>

Applied, thank you.