From 733326a087253be0a16c6f0e7a55ed6802af494c 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 2/4] net: hdlc_raw_eth: Clear the IFF_TX_SKB_SHARING flag
 after calling ether_setup
Git-commit: 5fce1e43e2d5bf2f7e3224d7b99b1c65ab2c26e2
References: git-fixes
Patch-mainline: v5.10-rc1

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 8bd3ed905813..676dea2918bf 100644
--- a/drivers/net/wan/hdlc_raw_eth.c
+++ b/drivers/net/wan/hdlc_raw_eth.c
@@ -102,6 +102,7 @@ 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