can: c_can: fix null-ptr-deref on ioctl()
The pdev maybe not a platform device, e.g. c_can_pci device, in this
case, calling to_platform_device() would not make sense. Also, per the
comment in drivers/net/can/c_can/c_can_ethtool.c, @bus_info should
match dev_name() string, so I am replacing this with dev_name() to fix
this issue.
[ 1.458583] BUG: unable to handle page fault for address: 0000000100000000
[ 1.460921] RIP: 0010:strnlen+0x1a/0x30
[ 1.466336] ? c_can_get_drvinfo+0x65/0xb0 [c_can]
[ 1.466597] ethtool_get_drvinfo+0xae/0x360
[ 1.466826] dev_ethtool+0x10f8/0x2970
[ 1.467880] sock_ioctl+0xef/0x300
Fixes: 2722ac986e93 ("can: c_can: add ethtool support")
Link: https://lore.kernel.org/r/20210906233704.1162666-1-ztong0001@gmail.com
Cc: stable@vger.kernel.org # 5.14+
Signed-off-by: Tong Zhang <ztong0001@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/drivers/net/can/c_can/c_can_ethtool.c b/drivers/net/can/c_can/c_can_ethtool.c
index cd5f07f..377c7d2 100644
--- a/drivers/net/can/c_can/c_can_ethtool.c
+++ b/drivers/net/can/c_can/c_can_ethtool.c
@@ -15,10 +15,8 @@
struct ethtool_drvinfo *info)
{
struct c_can_priv *priv = netdev_priv(netdev);
- struct platform_device *pdev = to_platform_device(priv->device);
-
strscpy(info->driver, "c_can", sizeof(info->driver));
- strscpy(info->bus_info, pdev->name, sizeof(info->bus_info));
+ strscpy(info->bus_info, dev_name(priv->device), sizeof(info->bus_info));
}
static void c_can_get_ringparam(struct net_device *netdev,
