Re: [PATCH v3 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 24.11.21 15:50, Dan Carpenter wrote:
> If the last channel is not available then "dev" is freed.  Fortunately,
> we can just use "pdev->irq" instead.
> 
> Also we should check if at least one channel was set up.
> 
> Fixes: fd734c6f25ae ("can/sja1000: add driver for EMS PCMCIA card")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>

Thanks Dan!


> ---
> v3: add a check for if there is a channel.
> v2: fix a bug in v1.  Only one channel is required but my patch returned
>      if any channel was unavailable.
> 
>   drivers/net/can/sja1000/ems_pcmcia.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/sja1000/ems_pcmcia.c b/drivers/net/can/sja1000/ems_pcmcia.c
> index e21b169c14c0..4642b6d4aaf7 100644
> --- a/drivers/net/can/sja1000/ems_pcmcia.c
> +++ b/drivers/net/can/sja1000/ems_pcmcia.c
> @@ -234,7 +234,12 @@ static int ems_pcmcia_add_card(struct pcmcia_device *pdev, unsigned long base)
>   			free_sja1000dev(dev);
>   	}
>   
> -	err = request_irq(dev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
> +	if (!card->channels) {
> +		err = -ENODEV;
> +		goto failure_cleanup;
> +	}
> +
> +	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
>   			  DRV_NAME, card);
>   	if (!err)
>   		return 0;
>