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 <[email protected]>
> ---
>
> 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
--
Pengutronix e.K. | Marc Kleine-Budde |
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