Re: [PATCH][RESEND][ISDN] Guard against a potential NULL pointer dereference in old_capi_manufacturer()

[Karsten Keil <kkeil@suse.de>]

On Sat, Aug 04, 2007 at 08:31:54PM +0200, Jesper Juhl wrote:
> (first send: Monday 25 June 2007, resending due to no response)
> (resending again on August 8'th, 2007)
> 
> 
> In drivers/isdn/capi/kcapi.c::old_capi_manufacturer(), if the call 
> to get_capi_ctr_by_nr(ldef.contr); in line 823 returns NULL, then 
> we'll be dereferencing a NULL pointer in the very next line.
> 
> (Found by Coverity checker as bug #402)
> 
> 
> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>

Acked-by: Karsten Keil <kkeil@suse.de>

> ---
> 
>  drivers/isdn/capi/kcapi.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/isdn/capi/kcapi.c b/drivers/isdn/capi/kcapi.c
> index 3ed34f7..3f9e962 100644
> --- a/drivers/isdn/capi/kcapi.c
> +++ b/drivers/isdn/capi/kcapi.c
> @@ -821,6 +821,8 @@ static int old_capi_manufacturer(unsigned int cmd, void 
> __user *data)
>  				return -EFAULT;
>  		}
>  		card = get_capi_ctr_by_nr(ldef.contr);
> +		if (!card)
> +			return -EINVAL;
>  		card = capi_ctr_get(card);
>  		if (!card)
>  			return -ESRCH;
> 
> -
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-- 
Karsten Keil
SuSE Labs
ISDN and VOIP development
SUSE LINUX Products GmbH, Maxfeldstr.5 90409 Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg)