[PATCH v2 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[PATCH v2 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[Dan Carpenter]

If the last channel is not available then "dev" is freed.  Fortunately,
we can just use "pdev->irq" instead.

Fixes: fd734c6f25ae ("can/sja1000: add driver for EMS PCMCIA card")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: In the first version, I just failed the probe.  Sorry about that.

 drivers/net/can/sja1000/ems_pcmcia.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/sja1000/ems_pcmcia.c b/drivers/net/can/sja1000/ems_pcmcia.c
index e21b169c14c0..391a8253ed6f 100644
--- a/drivers/net/can/sja1000/ems_pcmcia.c
+++ b/drivers/net/can/sja1000/ems_pcmcia.c
@@ -234,7 +234,7 @@ 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,
+	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
 			  DRV_NAME, card);
 	if (!err)
 		return 0;
-- 
2.20.1

Re: [PATCH v2 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[Oliver Hartkopp]

Hello Dan,

On 24.11.21 07:56, Dan Carpenter wrote:
> If the last channel is not available then "dev" is freed.  Fortunately,
> we can just use "pdev->irq" instead.

But in the case that we do not find any channel the irq for the card is 
still requested (via pdev->irq).

> 
> Fixes: fd734c6f25ae ("can/sja1000: add driver for EMS PCMCIA card")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: In the first version, I just failed the probe.  Sorry about that.
> 
>   drivers/net/can/sja1000/ems_pcmcia.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/can/sja1000/ems_pcmcia.c b/drivers/net/can/sja1000/ems_pcmcia.c
> index e21b169c14c0..391a8253ed6f 100644
> --- a/drivers/net/can/sja1000/ems_pcmcia.c
> +++ b/drivers/net/can/sja1000/ems_pcmcia.c
> @@ -234,7 +234,7 @@ 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,

When adding this check, we should be fine:

+	if (card->channels)

> +	err = request_irq(pdev->irq, &ems_pcmcia_interrupt, IRQF_SHARED,
>   			  DRV_NAME, card);
>   	if (!err)
>   		return 0;
> 

Thanks for checking this code after so many years!

I saved that 17 year old EMS PCMCIA Card from my former CAN hardware box 
two weeks ago and made a 5.16-rc2 run on a 2006 Samsung X20 with Pentium 
M 1.7GHz yesterday. My only machine here at home with a PCMCIA slot :-D

https://www.amazon.de/Samsung-Centrino-1-73GHz-Graphic-Accelerator/dp/B000AXSIRE

And it still works with the CAN card!

Best regards,
Oliver

Re: [PATCH v2 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[Dan Carpenter]

On Wed, Nov 24, 2021 at 08:37:27AM +0100, Oliver Hartkopp wrote:
> Hello Dan,
> 
> On 24.11.21 07:56, Dan Carpenter wrote:
> > If the last channel is not available then "dev" is freed.  Fortunately,
> > we can just use "pdev->irq" instead.
> 
> But in the case that we do not find any channel the irq for the card is
> still requested (via pdev->irq).
> 
> > 
> > Fixes: fd734c6f25ae ("can/sja1000: add driver for EMS PCMCIA card")
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > ---
> > v2: In the first version, I just failed the probe.  Sorry about that.
> > 
> >   drivers/net/can/sja1000/ems_pcmcia.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/can/sja1000/ems_pcmcia.c b/drivers/net/can/sja1000/ems_pcmcia.c
> > index e21b169c14c0..391a8253ed6f 100644
> > --- a/drivers/net/can/sja1000/ems_pcmcia.c
> > +++ b/drivers/net/can/sja1000/ems_pcmcia.c
> > @@ -234,7 +234,7 @@ 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,
> 
> When adding this check, we should be fine:
> 
> +	if (card->channels)

Sure,  I will send a v3 with that.

regards,
dan carpenter

Re: [PATCH v2 net] can: sja1000: fix use after free in ems_pcmcia_add_card()

[Oliver Hartkopp]

On 24.11.21 09:57, Dan Carpenter wrote:
> On Wed, Nov 24, 2021 at 08:37:27AM +0100, Oliver Hartkopp wrote:
>> Hello Dan,
>>
>> On 24.11.21 07:56, Dan Carpenter wrote:
>>> If the last channel is not available then "dev" is freed.  Fortunately,
>>> we can just use "pdev->irq" instead.
>>
>> But in the case that we do not find any channel the irq for the card is
>> still requested (via pdev->irq).
>>
>>>
>>> Fixes: fd734c6f25ae ("can/sja1000: add driver for EMS PCMCIA card")
>>> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
>>> ---
>>> v2: In the first version, I just failed the probe.  Sorry about that.
>>>
>>>    drivers/net/can/sja1000/ems_pcmcia.c | 2 +-
>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/can/sja1000/ems_pcmcia.c b/drivers/net/can/sja1000/ems_pcmcia.c
>>> index e21b169c14c0..391a8253ed6f 100644
>>> --- a/drivers/net/can/sja1000/ems_pcmcia.c
>>> +++ b/drivers/net/can/sja1000/ems_pcmcia.c
>>> @@ -234,7 +234,7 @@ 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,
>>
>> When adding this check, we should be fine:
>>
>> +	if (card->channels)
> 
> Sure,  I will send a v3 with that.

With these discussed changes you might directly add my

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

Thanks,
Oliver