From 0667162ef0600cb452b9b07ebd1e976fa68f998e Mon Sep 17 00:00:00 2001
From: Xie He <xie.he.0141@gmail.com>
Date: Mon, 19 Oct 2020 23:34:20 -0700
Subject: [PATCH 10/11] net: hdlc_raw_eth: Clear the IFF_TX_SKB_SHARING flag
 after calling ether_setup
Git-commit: 5fce1e43e2d5bf2f7e3224d7b99b1c65ab2c26e2
Patch-mainline: v5.10-rc1
References: git-fixes

This driver calls ether_setup to set up the network device.
The ether_setup function would add the IFF_TX_SKB_SHARING flag to the
device. This flag indicates that it is safe to transmit shared skbs to
the device.

However, this is not true. This driver may pad the frame (in eth_tx)
before transmission, so the skb may be modified.

Fixes: 550fd08c2ceb ("net: Audit drivers to identify those needing IFF_TX_SKB_SHARING cleared")
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Krzysztof Halasa <khc@pm.waw.pl>
Signed-off-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201020063420.187497-1-xie.he.0141@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
 drivers/net/wan/hdlc_raw_eth.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wan/hdlc_raw_eth.c b/drivers/net/wan/hdlc_raw_eth.c
index 08e0a46501de..c70a518b8b47 100644
--- a/drivers/net/wan/hdlc_raw_eth.c
+++ b/drivers/net/wan/hdlc_raw_eth.c
@@ -99,6 +99,7 @@ static int raw_eth_ioctl(struct net_device *dev, struct ifreq *ifr)
 		old_qlen = dev->tx_queue_len;
 		ether_setup(dev);
 		dev->tx_queue_len = old_qlen;
+		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 		eth_hw_addr_random(dev);
 		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);
-- 
2.16.4