[Devel] [PATCH 46/47] net: skb: check the boundrary of drop reason in kfree_skb_reason()

[Nikolay Borisov]

From: Menglong Dong <imagedong at tencent.com>

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 at tencent.com>
Reviewed-by: Hao Peng <flyingpeng at tencent.com>
Signed-off-by: Menglong Dong <imagedong at tencent.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Acked-by: Nikolay Borisov <nborisov at suse.com>
Signed-off-by: Nikolay Borisov <nikolay.borisov at virtuozzo.com>
---
 net/core/skbuff.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9d45ad819ea7..2e067ec51ec6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -774,6 +774,8 @@ 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);
 }
-- 
2.34.1