From: Menglong Dong <imagedong@tencent.com>
Date: Fri, 13 May 2022 03:03:37 +0000 (+0800)
Subject: net: skb: check the boundrary of drop reason in kfree_skb_reason()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=20bbcd0a94c6686c2692e6f7081163c233d7ce40;p=linux.git

net: skb: check the boundrary of drop reason in kfree_skb_reason()

Sometimes, we may forget to reset skb drop reason to NOT_SPECIFIED after
we make it the return value of the functions with return type of enum
skb_drop_reason, such as tcp_inbound_md5_hash. Therefore, its value can
be SKB_NOT_DROPPED_YET(0), which is invalid for kfree_skb_reason().

So we check the range of drop reason in kfree_skb_reason() with
DEBUG_NET_WARN_ON_ONCE().

Reviewed-by: Jiang Biao <benbjiang@tencent.com>
Reviewed-by: Hao Peng <flyingpeng@tencent.com>
Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index bd16e158b3668..2fea964f09d80 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -771,6 +771,8 @@ void kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
 	if (!skb_unref(skb))
 		return;
 
+	DEBUG_NET_WARN_ON_ONCE(reason <= 0 || reason >= SKB_DROP_REASON_MAX);
+
 	trace_kfree_skb(skb, __builtin_return_address(0), reason);
 	__kfree_skb(skb);
 }