If skb allocation fails, the pointer to struct can_frame is NULL. This
is actually handled everywhere inside ctucan_err_interrupt() except for
the only place.

Add the missed NULL check.

Found by Linux Verification Center (linuxtesting.org) with SVACE static
analysis tool.

Fixes: 2dcb8e8782d8 ("can: ctucanfd: add support for CTU CAN FD open-source IP core - bus independent part.")
Cc: stable@vger.kernel.org
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
---
 drivers/net/can/ctucanfd/ctucanfd_base.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/ctucanfd/ctucanfd_base.c b/drivers/net/can/ctucanfd/ctucanfd_base.c
index 64c349fd4600..f65c1a1e05cc 100644
--- a/drivers/net/can/ctucanfd/ctucanfd_base.c
+++ b/drivers/net/can/ctucanfd/ctucanfd_base.c
@@ -867,10 +867,12 @@ static void ctucan_err_interrupt(struct net_device *ndev, u32 isr)
 			}
 			break;
 		case CAN_STATE_ERROR_ACTIVE:
-			cf->can_id |= CAN_ERR_CNT;
-			cf->data[1] = CAN_ERR_CRTL_ACTIVE;
-			cf->data[6] = bec.txerr;
-			cf->data[7] = bec.rxerr;
+			if (skb) {
+				cf->can_id |= CAN_ERR_CNT;
+				cf->data[1] = CAN_ERR_CRTL_ACTIVE;
+				cf->data[6] = bec.txerr;
+				cf->data[7] = bec.rxerr;
+			}
 			break;
 		default:
 			netdev_warn(ndev, "unhandled error state (%d:%s)!\n",
-- 
2.39.5

On 15/01/2025 at 00:21, Fedor Pchelkin wrote:
> If skb allocation fails, the pointer to struct can_frame is NULL. This
> is actually handled everywhere inside ctucan_err_interrupt() except for
> the only place.
> 
> Add the missed NULL check.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE static
> analysis tool.
> 
> Fixes: 2dcb8e8782d8 ("can: ctucanfd: add support for CTU CAN FD open-source IP core - bus independent part.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>

Reviewed-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>

Yours sincerely,
Vincent Mailhol

Hello Fedor,

thanks for spotting the problem.

On Tuesday 14 of January 2025 16:21:38 Fedor Pchelkin wrote:
> If skb allocation fails, the pointer to struct can_frame is NULL. This
> is actually handled everywhere inside ctucan_err_interrupt() except for
> the only place.
>
> Add the missed NULL check.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE static
> analysis tool.
>
> Fixes: 2dcb8e8782d8 ("can: ctucanfd: add support for CTU CAN FD open-source
> IP core - bus independent part.") Cc: stable@vger.kernel.org
> Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>

Acked-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>

> ---
>  drivers/net/can/ctucanfd/ctucanfd_base.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/can/ctucanfd/ctucanfd_base.c
> b/drivers/net/can/ctucanfd/ctucanfd_base.c index 64c349fd4600..f65c1a1e05cc
> 100644
> --- a/drivers/net/can/ctucanfd/ctucanfd_base.c
> +++ b/drivers/net/can/ctucanfd/ctucanfd_base.c
> @@ -867,10 +867,12 @@ static void ctucan_err_interrupt(struct net_device
> *ndev, u32 isr) }
>  			break;
>  		case CAN_STATE_ERROR_ACTIVE:
> -			cf->can_id |= CAN_ERR_CNT;
> -			cf->data[1] = CAN_ERR_CRTL_ACTIVE;
> -			cf->data[6] = bec.txerr;
> -			cf->data[7] = bec.rxerr;
> +			if (skb) {
> +				cf->can_id |= CAN_ERR_CNT;
> +				cf->data[1] = CAN_ERR_CRTL_ACTIVE;
> +				cf->data[6] = bec.txerr;
> +				cf->data[7] = bec.rxerr;
> +			}
>  			break;
>  		default:
>  			netdev_warn(ndev, "unhandled error state (%d:%s)!\n",


-- 

                Pavel Pisa
    phone:      +420 603531357
    e-mail:     pisa@cmp.felk.cvut.cz
    Department of Control Engineering FEE CVUT
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