releases/4.4.181/ethtool-check-the-return-value-of-get_regs_len.patch

From f9fc54d313fab2834f44f516459cdc8ac91d797f Mon Sep 17 00:00:00 2001
From: Yunsheng Lin <linyunsheng@huawei.com>
Date: Wed, 26 Dec 2018 19:51:46 +0800
Subject: ethtool: check the return value of get_regs_len

From: Yunsheng Lin <linyunsheng@huawei.com>

commit f9fc54d313fab2834f44f516459cdc8ac91d797f upstream.

The return type for get_regs_len in struct ethtool_ops is int,
the hns3 driver may return error when failing to get the regs
len by sending cmd to firmware.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/core/ethtool.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -428,8 +428,13 @@ static noinline_for_stack int ethtool_ge
 		if (rc >= 0)
 			info.n_priv_flags = rc;
 	}
-	if (ops->get_regs_len)
-		info.regdump_len = ops->get_regs_len(dev);
+	if (ops->get_regs_len) {
+		int ret = ops->get_regs_len(dev);
+
+		if (ret > 0)
+			info.regdump_len = ret;
+	}
+
 	if (ops->get_eeprom_len)
 		info.eedump_len = ops->get_eeprom_len(dev);
 
@@ -883,6 +888,9 @@ static int ethtool_get_regs(struct net_d
 		return -EFAULT;
 
 	reglen = ops->get_regs_len(dev);
+	if (reglen <= 0)
+		return reglen;
+
 	if (regs.len > reglen)
 		regs.len = reglen;