net: ipv4: fix return value check in esp_remove_trailer

In esp_remove_trailer(), to avoid an unexpected result returned by
pskb_trim, we should check the return value of pskb_trim().
Signed-off-by: Ma Ke <make_ruc2021@163.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/ipv4/esp4.c

@@ -732,7 +732,9 @@ static inline int esp_remove_trailer(struct sk_buff *skb)
 		skb->csum = csum_block_sub(skb->csum, csumdiff,
 					   skb->len - trimlen);
 	}
-	pskb_trim(skb, skb->len - trimlen);
+	ret = pskb_trim(skb, skb->len - trimlen);
+	if (unlikely(ret))
+		return ret;
 
 	ret = nexthdr[1];