[PATCH v2 05/17] can: dev: register_candev(): ensure that bittiming const are valid

[Marc Kleine-Budde <mkl@pengutronix.de>]

Implement the function can_bittiming_const_valid() to check the
validity of the specified bit timing constant. Call this function from
register_candev() to check the bit timing constants during the
registration of the CAN interface.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev/dev.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/can/dev/dev.c b/drivers/net/can/dev/dev.c
index c1956b1e9faf..3b51055be40e 100644
--- a/drivers/net/can/dev/dev.c
+++ b/drivers/net/can/dev/dev.c
@@ -498,6 +498,18 @@ static int can_get_termination(struct net_device *ndev)
 	return 0;
 }
 
+static bool
+can_bittiming_const_valid(const struct can_bittiming_const *btc)
+{
+	if (!btc)
+		return true;
+
+	if (!btc->sjw_max)
+		return false;
+
+	return true;
+}
+
 /* Register the CAN network device */
 int register_candev(struct net_device *dev)
 {
@@ -518,6 +530,10 @@ int register_candev(struct net_device *dev)
 	if (!priv->data_bitrate_const != !priv->data_bitrate_const_cnt)
 		return -EINVAL;
 
+	if (!can_bittiming_const_valid(priv->bittiming_const) ||
+	    !can_bittiming_const_valid(priv->data_bittiming_const))
+		return -EINVAL;
+
 	if (!priv->termination_const) {
 		err = can_get_termination(dev);
 		if (err)
-- 
2.39.1