ping: Check return value of function 'ping_queue_rcv_skb'

stable inclusion
from linux-4.19.196
commit 1d86498c252e6b680710a31c3a003491477dd50d

--------------------------------

[ Upstream commit 9d44fa3e ]

Function 'ping_queue_rcv_skb' not always return success, which will
also return fail. If not check the wrong return value of it, lead to function
`ping_rcv` return success.
Signed-off-by: NZheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/ipv4/ping.c

@@ -968,6 +968,7 @@ bool ping_rcv(struct sk_buff *skb)
 	struct sock *sk;
 	struct net *net = dev_net(skb->dev);
 	struct icmphdr *icmph = icmp_hdr(skb);
+	bool rc = false;
 
 	/* We assume the packet has already been checked by icmp_rcv */
 
@@ -982,14 +983,15 @@ bool ping_rcv(struct sk_buff *skb)
 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
 		pr_debug("rcv on socket %p\n", sk);
-		if (skb2)
-			ping_queue_rcv_skb(sk, skb2);
+		if (skb2 && !ping_queue_rcv_skb(sk, skb2))
+			rc = true;
 		sock_put(sk);
-		return true;
 	}
-	pr_debug("no socket, dropping\n");
 
-	return false;
+	if (!rc)
+		pr_debug("no socket, dropping\n");
+
+	return rc;
 }
 EXPORT_SYMBOL_GPL(ping_rcv);