[RFC,12/13] can: slcan: extend the protocol with error info
diff mbox series

Message ID 20220607094752.1029295-13-dario.binacchi@amarulasolutions.com
State New
Headers show
Series
  • can: slcan: extend supported features
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Commit Message

Dario Binacchi June 7, 2022, 9:47 a.m. UTC 
It extends the protocol to receive the adapter CAN communication errors
and forward them to the netdev upper levels.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

 drivers/net/can/slcan/slcan-core.c | 104 ++++++++++++++++++++++++++++-
 1 file changed, 103 insertions(+), 1 deletion(-)

Comments

Marc Kleine-Budde June 7, 2022, 10:56 a.m. UTC | #1 
On 07.06.2022 11:47:51, Dario Binacchi wrote:
> It extends the protocol to receive the adapter CAN communication errors
> and forward them to the netdev upper levels.
> 
> Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
> ---
> 
>  drivers/net/can/slcan/slcan-core.c | 104 ++++++++++++++++++++++++++++-
>  1 file changed, 103 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
> index b813a59534a3..02e7c14de45c 100644
> --- a/drivers/net/can/slcan/slcan-core.c
> +++ b/drivers/net/can/slcan/slcan-core.c
> @@ -182,8 +182,92 @@ int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
>    *			STANDARD SLCAN DECAPSULATION			 *
>    ************************************************************************/
>  
> +static void slc_bump_err(struct slcan *sl)
> +{
> +	struct net_device *dev = sl->dev;
> +	struct sk_buff *skb;
> +	struct can_frame *cf;
> +	char *cmd = sl->rbuff;
> +	bool rx_errors = false, tx_errors = false;
> +	int i, len;
> +
> +	if (*cmd != 'e')
> +		return;
> +
> +	cmd += SLC_CMD_LEN;
> +	/* get len from sanitized ASCII value */

What happens is a malicious device sends a wrong len value, that's
longer than the RX'ed data?

> +	len = *cmd++;
> +	if (len >= '0' && len < '9')
> +		len -= '0';
> +	else
> +		return;
> +
> +	skb = alloc_can_err_skb(dev, &cf);

Please continue error handling, even if no skb can be allocated.

> +	if (unlikely(!skb))
> +		return;
> +
> +	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
> +	for (i = 0; i < len; i++, cmd++) {
> +		switch (*cmd) {
> +		case 'a':
> +			netdev_dbg(dev, "ACK error\n");
> +			cf->can_id |= CAN_ERR_ACK;
> +			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
> +			tx_errors = true;
> +			break;
> +		case 'b':
> +			netdev_dbg(dev, "Bit0 error\n");
> +			cf->data[2] |= CAN_ERR_PROT_BIT0;
> +			tx_errors = true;
> +			break;
> +		case 'B':
> +			netdev_dbg(dev, "Bit1 error\n");
> +			cf->data[2] |= CAN_ERR_PROT_BIT1;
> +			tx_errors = true;
> +			break;
> +		case 'c':
> +			netdev_dbg(dev, "CRC error\n");
> +			cf->data[2] |= CAN_ERR_PROT_BIT;
> +			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
> +			rx_errors = true;
> +			break;
> +		case 'f':
> +			netdev_dbg(dev, "Form Error\n");
> +			cf->data[2] |= CAN_ERR_PROT_FORM;
> +			rx_errors = true;
> +			break;
> +		case 'o':
> +			netdev_dbg(dev, "Rx overrun error\n");
> +			cf->can_id |= CAN_ERR_CRTL;
> +			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
> +			dev->stats.rx_over_errors++;
> +			dev->stats.rx_errors++;
> +			break;
> +		case 'O':
> +			netdev_dbg(dev, "Tx overrun error\n");
> +			cf->can_id |= CAN_ERR_CRTL;
> +			cf->data[1] = CAN_ERR_CRTL_TX_OVERFLOW;
> +			dev->stats.tx_errors++;
> +			break;
> +		case 's':
> +			netdev_dbg(dev, "Stuff error\n");
> +			cf->data[2] |= CAN_ERR_PROT_STUFF;
> +			rx_errors = true;
> +			break;
> +		}
> +	}
> +
> +	if (rx_errors)
> +		dev->stats.rx_errors++;
> +
> +	if (tx_errors)
> +		dev->stats.tx_errors++;
> +
> +	netif_rx(skb);
> +}
> +

Marc

Patch
diff mbox series 

diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
index b813a59534a3..02e7c14de45c 100644
--- a/drivers/net/can/slcan/slcan-core.c
+++ b/drivers/net/can/slcan/slcan-core.c
@@ -182,8 +182,92 @@  int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
   *			STANDARD SLCAN DECAPSULATION			 *
   ************************************************************************/
 
+static void slc_bump_err(struct slcan *sl)
+{
+	struct net_device *dev = sl->dev;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	char *cmd = sl->rbuff;
+	bool rx_errors = false, tx_errors = false;
+	int i, len;
+
+	if (*cmd != 'e')
+		return;
+
+	cmd += SLC_CMD_LEN;
+	/* get len from sanitized ASCII value */
+	len = *cmd++;
+	if (len >= '0' && len < '9')
+		len -= '0';
+	else
+		return;
+
+	skb = alloc_can_err_skb(dev, &cf);
+	if (unlikely(!skb))
+		return;
+
+	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+	for (i = 0; i < len; i++, cmd++) {
+		switch (*cmd) {
+		case 'a':
+			netdev_dbg(dev, "ACK error\n");
+			cf->can_id |= CAN_ERR_ACK;
+			cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+			tx_errors = true;
+			break;
+		case 'b':
+			netdev_dbg(dev, "Bit0 error\n");
+			cf->data[2] |= CAN_ERR_PROT_BIT0;
+			tx_errors = true;
+			break;
+		case 'B':
+			netdev_dbg(dev, "Bit1 error\n");
+			cf->data[2] |= CAN_ERR_PROT_BIT1;
+			tx_errors = true;
+			break;
+		case 'c':
+			netdev_dbg(dev, "CRC error\n");
+			cf->data[2] |= CAN_ERR_PROT_BIT;
+			cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+			rx_errors = true;
+			break;
+		case 'f':
+			netdev_dbg(dev, "Form Error\n");
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+			rx_errors = true;
+			break;
+		case 'o':
+			netdev_dbg(dev, "Rx overrun error\n");
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+			dev->stats.rx_over_errors++;
+			dev->stats.rx_errors++;
+			break;
+		case 'O':
+			netdev_dbg(dev, "Tx overrun error\n");
+			cf->can_id |= CAN_ERR_CRTL;
+			cf->data[1] = CAN_ERR_CRTL_TX_OVERFLOW;
+			dev->stats.tx_errors++;
+			break;
+		case 's':
+			netdev_dbg(dev, "Stuff error\n");
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+			rx_errors = true;
+			break;
+		}
+	}
+
+	if (rx_errors)
+		dev->stats.rx_errors++;
+
+	if (tx_errors)
+		dev->stats.tx_errors++;
+
+	netif_rx(skb);
+}
+
 /* Send one completely decapsulated can_frame to the network layer */
-static void slc_bump(struct slcan *sl)
+static void slc_bump_frame(struct slcan *sl)
 {
 	struct sk_buff *skb;
 	struct can_frame cf, *scf;
@@ -257,6 +341,24 @@  static void slc_bump(struct slcan *sl)
 	netif_rx(skb);
 }
 
+static void slc_bump(struct slcan *sl)
+{
+	switch (sl->rbuff[0]) {
+	case 'r':
+		fallthrough;
+	case 't':
+		fallthrough;
+	case 'R':
+		fallthrough;
+	case 'T':
+		return slc_bump_frame(sl);
+	case 'e':
+		return slc_bump_err(sl);
+	default:
+		return;
+	}
+}
+
 /* parse tty input stream */
 static void slcan_unesc(struct slcan *sl, unsigned char s)
 {